JP3320046B2 - Valve train for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camshaft on which a valve cam is provided, and a swinging support portion swingably supported by a support member provided on a cylinder head. A rocker arm in which the base ends of a pair of support walls facing each other at a distance in the direction along the axis are integrally connected, a support shaft supported between the support walls, and the support via a bearing. The present invention relates to a valve operating device for an internal combustion engine, comprising: a roller rotatably supported on a shaft and rollingly contacting the valve operating cam.

[0002]

2. Description of the Related Art Conventionally, such a valve train is disclosed in
It is already known in US Pat.

[0003]

The rocker arm in the above-mentioned conventional valve operating device includes a swing support portion which is swingably supported by a pivot as a support member, and a pair of swing support portions whose base ends are connected to the swing support portion. And an end valve connecting the ends of the support walls. An engine valve is interlocked and connected to the end connection, and a support shaft is supported between the support walls. A roller that is in rolling contact with the valve cam is rotatably supported. However, the surface of the rocking support portion facing the roller is formed as a flat surface along a plane intersecting a straight line connecting the rocking fulcrum by the pivot of the rocking support portion and the rotation axis of the roller. It is hard to say that the rigidity is excellent, and it is desired to further increase the rigidity of the rocker arm. Moreover, it is desirable to avoid increasing the size of the rocker arm when increasing the rigidity of the rocker arm.

The present invention has been made in view of such circumstances, and in particular, while avoiding an increase in the size of the free rocker arm.
And to provide a valve operating system for an internal combustion engine with enhanced rigidity.

[0005]

Means for Solving the Problems To achieve the above object, an invention according to claim 1 comprises a plurality of blocks arranged adjacent to each other.
A lock shaft, a camshaft provided with a plurality of valve cams for swinging each rocker arm , and each rocker arm.
Interlock switching means that can switch between interlock and interlock
The plurality of rocker arms are linked to and connected to the engine valve.
Drive rocker arm to be operated and interlocking release of the interlocking switching means
A free rocker arm that is free to the engine valve in the state
The rocker arm includes a pair of rocker arms which are opposed to a rocking support portion which is rockably supported by a support member provided on the cylinder head at a distance from each other in a direction along a rocking axis of the rocking support portion. The base end of the support wall is not
In the valve train of an internal combustion engine, a roller supported by a support shaft supported between the two support walls and rollingly contacting a valve train cam for swinging a free rocker arm is rotatably supported via a bearing . , Between the base ends of the support walls
The connecting upper connecting wall faces the upper outer peripheral surface of the roller.
While being protruded from the swing support portion in such a manner as to connect the lower portions of the base ends of the support walls and to be connected to the upper connection wall.
A lower connecting wall having a large protrusion amount is protruded from the swing support portion so as to face a lower outer peripheral surface of the roller , and
Roller freely in the direction that allows the roller to come into rolling contact with the valve cam.
A pressing means for urging the hook arm in an axial direction of the support shaft;
Connected to one end of the lower connecting wall along the two supporting wall portions
Abutting against a receiving portion protruding from one of the lower portions .

According to such a configuration, the free rocker arm
The base ends of the pair of support walls of the arm are connected by the upper connection wall and the lower connection wall, so that the support rigidity of the support shaft by both support walls is increased and the rigidity of the entire free rocker arm is improved. Will also increase. Moreover, since the lower connecting wall is opposed to and close to the lower portion of the roller, it is also possible to temporarily hold oil between the lower connecting wall and the roller, and to transfer the oil held between the lower connecting wall and the roller to the roller and the spindle. It is also possible to reduce the rotational resistance of the roller by guiding to the bearing between them. In addition, the upper connecting wall and the lower connecting wall are arranged by effectively utilizing the space between the roller and the swing support portion, and the rocker arm does not become large due to the upper connecting wall and the lower connecting wall. Also,
The hit load received from the valve cam is lower than the upper part of the spindle
Is larger, but in the present invention, especially the upper connecting wall
The lower connecting wall, which protrudes more than
Can support the lower part of both supporting walls that support
This is advantageous for improving the rigidity of both supporting walls, and
Pressing means for urging the cocker arm extends along the axis of the support shaft.
Connected to one end of the lower connecting wall
Abutting against a receiving portion projecting from the
The rigidity of the receiving part where the load acts from the lower connecting wall
Can be enhanced.

[0007] The invention according to claim 2 is the invention according to claim 1.
In addition to the configuration of the invention described, the swing support portion of said free rocker <br/> arm portion facing the spark plug insertion tube attached to shea cylinder head, recessed on the opposite side of the spark plug insertion tube A notch is provided, and at least a part of the lower connecting wall and at least a part of the notch are arranged on the same plane orthogonal to a swing axis of the free rocker arm. Features.

According to the configuration of the second aspect of the present invention, the spark plug insertion cylinder and the free rocker arm can be arranged as close as possible, and are formed in the internal combustion engine so as to accommodate the valve gear. miniaturization of the valve chamber, as well as its own
Can that help to a reduction in the weight of the reason the rocker arm. Moreover, it is possible to compensate for the lowering of the rigidity of the swing support portion due to the provision of the notch by the lower connecting wall.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

FIGS. 1 to 13 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view showing a part of a valve train, and is a sectional view taken along line 1-1 in FIG. Is a plan view of FIG.
3 is a sectional view taken along line 3-3 in FIG. 2, FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, FIG. 5 is an enlarged sectional view taken along line 5-5 in FIG. 2, and FIG. Sectional view corresponding to FIG. 5 in FIG. 7, FIG.
4 is a sectional view taken along line 7-7 of FIG. 2, FIG. 8 is a sectional view taken along line 8-8 of FIG. 4, FIG. 9 is a sectional view taken along line 9-9 of FIG.
11 is a sectional view taken along line 11-11 of FIG. 10, FIG. 12 is a plan view of the intake-side and exhaust-side valve trains, and FIG. 13 is a sectional view taken along line 13-13 of FIG.

First, referring to FIG.
The cylinder head 11 of the cylinder internal combustion engine is provided with a pair of intake valve ports 12 for each cylinder. The two intake valve ports 12 ...
The valves 13 are individually opened and closed by intake valves VI as engine valves. Stems 13 of the intake valves VI are provided with guide cylinders 14 provided on the cylinder head 11, respectively.
Is slidably fitted to. A retainer 1 provided at an upper end of a stem 13 projecting upward from each guide cylinder 14.
5 and the cylinder head 11 are provided with valve springs 16 surrounding the respective stems 13.
Are biased in a direction to close the intake valve ports 12.

Referring also to FIGS. 2 to 4, both intake valves V
An intake-side valve train 17I is connected to I and VI. The intake-side valve train 17I is connected to a camshaft 18 which is linked and connected to a crankshaft (not shown) at a reduction ratio of 1/2. , Which are linked to and connected to one of the intake valves VI.
The drive rocker arm 19, a second drive rocker arm 20 linked to and connected to the other of the two intake valves VI, and a free rocker arm 21 that can be free with respect to the two intake valves VI.
And a fixed rocker shaft 22 as a support member having an axis parallel to the camshaft 18 and supporting the rocker arms 19, 20, 21 in a common and swingable manner, and interlocking of the rocker arms 19-21. And interlocking switching means 23 capable of switching interlocking release.

The camshaft 18 includes a high-speed valve operating cam 2.
6 and low-speed valve operating cams 25, 25 arranged on both sides of the high-speed valve operating cam 26 corresponding to the two intake valves VI, respectively.

The high-speed valve operating cam 26 has a cam profile for opening and closing the intake valves VI in the high-speed operation range of the engine, and has an arc-shaped base circular portion 26a centered on the axis of the camshaft 18. And a high-order portion 26b projecting radially outward from the base circle portion 26a. The low-speed valve operating cam 25 has a cam profile for opening and closing the intake valves VI in the low-speed operation range of the engine.
A base circular portion 25a formed in an arc shape centered on the axis of the camshaft 18 and a protruding amount from the base circular portion 25a to the radial outside of the camshaft 18 are determined by a high-order portion of the high-speed valve cam 26. The upper portion 26b has a higher portion 25b which is smaller than the amount of protrusion from the base circle portion 26a and which extends from the base circle portion 25a over a central angle range narrower than that of the higher portion 26b.

The first drive rocker arm 19, the second drive rocker arm 20, and the free rocker arm 21 are arranged adjacent to each other so as to sandwich the free rocker arm 21 between the first and second drive rocker arms 19, 20. It is swingably supported.

First and second drive rocker arms 19, 2
Reference numeral 0 denotes swing support portions 19a and 20a that are swingably supported by the rocker shaft 22, and first support wall portions 31 ₁ and 32 ₁ whose base ends are respectively connected to the swing support portions 19a and 20a.
When, the first support wall 31 _1, 32 ₁ to opposed proximal and the pivot support portion 19a in a direction along the axis of the rocker shaft 22,
The second support wall portions 31 ₂ and 32 respectively connected to the 20a
₂ and two supporting wall portions 31 ₁ , 31 ₂ ;
Tip connecting portions 19b, 20 for connecting the tips of ₁ , 32 ₂
b are provided integrally with each other, and the stem 13 of each of the intake valves VI.
The tappet screws 27, 27 contacting the upper end of... The free rocker arm 21 has a rocking support portion 21a that is rockably supported by a rocker shaft 22.
When the first and support wall 33 ₁ which base is continuously provided on the pivot support portion 21a, the second in a direction along the axis of the rocker shaft 22 1
Proximal end opposite the support wall 33 ₁ is integrally provided with a ₂ second support wall portion 33 provided continuously to the swing support portion 21a.

The swing support portion 1 of the first drive rocker arm 19
Between 9a and the tip connecting portion 19b, the first and second support walls 31 _1, 31 ₂ opening 34 which is opened up and down so as to be defined on both sides with is provided, the low-speed valve operating cam 2
The first driving rocker arm 19 is arranged such that the cylindrical roller 28 that comes into rolling contact with the first driving rocker 5 is disposed in the opening 34.
It is supported rotatably. Also, the second drive rocker arm 2
0 between the rocking support portion 20a and the tip connecting portion 20b.
An opening 35 is provided which is opened up and down so that both sides are defined by the first and second support wall portions 32 ₁ and 32 ₂ .
A cylindrical roller 29 that is in rolling contact with the low-speed valve operating cam 25 is rotatably supported by the second drive rocker arm 20 so as to be disposed in the opening 35. Further, the free rocker arm 21 has the first and second support walls 3.
3 _1, 33 ₂ opening 36 which opens to the opposite side and up and down with the rocker shaft 22 so as to be defined on both sides is provided with a cylindrical roller 30 is the opening for rolling contact with the high-speed valve operating cam 26 It is rotatably supported by the free rocker arm 21 so as to be disposed on the portion 36.

[0018] The first support wall 31 ₁ of the first driving rocker arm 19, the free rocker arm 21 side first fitting hole 37 ₁ of the open bottom of the is provided parallel to the axis of the rocker shaft 22, the second the support wall portion 31 _2, the second fitting hole 37 ₂ which is open at both ends is provided with the first fitting bore 37 ₁ coaxially. First fitting hole 38 ₁ in the first support wall 32 ₁ is a free rocker arm 21 side in the second driving rocker arm 20 which is open at both ends is provided parallel to the axis of the rocker shaft 22, the second support wall portions 32 ₂ has a free rocker arm 2
Second fitting hole 38 having a bottom opening the 1 side ₂ is the first fitting hole 3
It provided ₈₁ coaxially. A first support wall portion 33 on the first drive rocker arm 19 side of the free rocker arm 21.
_{1 1} The first fitting hole 39 which opens at both ends is provided parallel to the axis of the rocker shaft 22 to, in the ₂ second support wall portion 33, the second fitting hole 39 ₂ which is open at both ends first Fitting hole 39
Provided coaxially with ₁ .

The first fitting hole 3 of the first drive rocker arm 19
7 ₁ one end of a cylindrical support shaft 41 until it abuts is fitted at its closed end to, the second fitting hole 37 ₂ the support shaft 41
Is fitted at the other end. The second drive rocker arm 20
Of the first fitting hole 38 _1, the end of the cylindrical support shaft 42 is fitted, the other end of the support shaft 42 to the second fitting hole 38 ₂ abuts on the closed end Mated. Further, the first and second fitting holes 39 ₁ and 39 ₂ of the free rocker arm 21 are provided.
The two ends of the cylindrical support shaft 43 are fitted to the respective shafts.

[0020] Referring also to FIG. 5, the second support wall 31 ₂ of the first driving rocker arm 19, the rocker shaft 2
With 2 and second fitting hole 37 ₂ of the insertion hole 44 communicating with the second fitting hole 37 ₂ of the inner surface extending linearly in a direction intersecting the straight line connecting the axis it is provided, at the upper end of the insertion hole 44 a first recess 80 which opens to the second upper surface of the support wall portion 31 ₂ through a second recess 81 which opening is provided on the lower surface lower end through to the second support wall 31 ₂ of the insertion hole 44, The first and second concave portions 80 and 81 are formed to have a larger diameter than the insertion hole 44.

Meanwhile, the outer surface of the support shaft 41 in correspondence with the opening of the insertion hole 44 into the second fitting hole 37 ₂ of the inner surface, the tangent of the virtual circle C about the axis of the support shaft 41 An engaging groove 50 extending along the direction is provided. A pin 47 extending linearly is inserted into the insertion hole 44 as shown in FIG. Engaged.

As shown in FIG. 5, both ends of the pin 47 inserted into the insertion hole 44 are caulked by flat punches 82 and 83 having outer diameters smaller than the inner diameters of the recesses 80 and 81, respectively. The swaging part 47 crushed in a disk shape
a, 47a are engaged with the step between the concave portions 80, 81 and the insertion hole 44, whereby the support shaft 41 is fixed to the first drive rocker arm 19.

[0023] The first support wall 32 ₁ of the second driving rocker arm 20, the support shaft 42 is fixed in the same structure as the fixing structure of the first driving rocker arm 19 of the support shaft 41. That is, the pin 48 having both ends caulked while being inserted into the insertion hole 45 provided in the first support wall 32 ₁ of the second driving rocker arm 20 is fitted in the first fitting hole 38 ₁ spindle 42 is engaged with an engaging groove 51 provided on the outer surface.

Furthermore in the first support wall 33 ₁ of the free rocker arm 21, the second driving rocker arm of the first fixing structure of the driving rocker arm 19 and the support shaft 42 of the supporting shaft 41 2
The support shaft 43 is fixed by a structure similar to the structure for fixing the shaft 43 to zero.
That is, the first support wall 33 ₁ of the free rocker arm 21
Engaging the engaging groove 52 which ends with being inserted into the insertion hole 46 provided with the pins 49 to be swaged is provided on the outer surface of the support shaft 43 is fitted to the first fitting hole 39 ₁ Is done.

The depth of each of the engagement grooves 50, 51, 52 is
Pins 47 and 4 corresponding to the respective engagement grooves 50 to 52
8, 49 or less of the radius, preferably each pin 47
４９49 is set to about 半径 of the radius. By doing so, not only the processing when forming the engagement grooves 50 to 52 on the support shafts 41 to 43 becomes easy but also the engagement grooves 50 to 52 are formed.
It is possible to prevent the rigidity of the support shafts 41 to 43 from being reduced as much as possible by the formation of.

The hardness of at least a portion of each of the pins 47 to 49 which engages with the engagement grooves 50 to 52, in this embodiment, the hardness of the portion of each of the pins 47 to 49 inserted into the insertion holes 44 to 46 is
Both ends of each of the pins 47 to 49, the insertion holes 44 in this embodiment.
The hardness is set to be higher than the hardness of the protruding end portion from # 46. Thus, each of the pins 47 to 49 is, for example, JIS SUJ2
By subjecting the pins 47 to 49 to intermediate portions in the axial direction, for example, by induction hardening, the hardness of a part of the outer surface of each of the pins 47 to 49 is increased. Thus,
Pin least hardness of a portion which engages the engaging groove 50 to 52 induction hardening by e.g. H _V 579 of 47 to 49
832, and pins 47 to 49 in the unhardened area.
Both end portions hardness of, for example, an H _V 180 to 260.

The roller 28 and the support shaft 41 are provided between the first and second support walls 31 ₁ and 31 _{2 of} the first drive rocker arm 19.
A needle bearing 53 is interposed between the first and second support rocker arms 20, and the first and second support wall portions 32 ₁ , 32 ₁ ,
A needle bearing 54 is interposed between the roller 29 and the support shaft 42 between the first and second support walls 32 _{1 and} 32 _{2, and} between the first and second support wall portions 33 ₁ and 33 ₂ of the free rocker arm 21.
A needle bearing 55 is interposed between and the support shaft 43.

In FIG. 7, a lost motion mechanism is provided below the free rocker arm 21 on the cylinder head 11 so as to apply a spring force to the free rocker arm 21 in a direction in which the roller 30 of the free rocker arm 21 comes into rolling contact with the high-speed valve cam 26. The lost motion mechanism 58 is provided with a bottomed cylindrical lifter 60 that is slidably fitted into a bottomed sliding hole 59 provided in the cylinder head 11 with its upper part opened. It comprises a closed end of the moving hole 59 and a spring 61 provided between the lifter 60.

On the other hand, the free rocker arm 21 receives the spring force from the lost motion mechanism 58 to lift the lifter 60.
Although it provided with a receiving portion 62 that contacts the upper end of the receiving portion 62, first and second support walls 33 _1, 33 the first support wall portion 33 of the ₂ free rocker arm 21 is provided with
₁ the pin 49 is inserted to secure the support shaft 43, whereas the fixed, is provided integrally with raised beneath the bottom of the second support wall 33 _2.

Referring to FIGS. 1 and 5, the swing support 19a of the first drive rocker arm 19 has the first and second rockers.
A lower connecting wall 85 for connecting the lower portions of the base ends of the support wall portions 31 ₁ and 31 ₂ is protruded so as to approach and face the lower outer peripheral surface of the roller 28, and the first and second support wall portions 31 are provided. _1, 31 upper connecting wall 86 for connecting the _two proximal upper
Are protruded so as to approach and face the upper outer peripheral surface of the roller 28, and the interval between the lower connecting wall 85 and the roller 28 is set smaller than the interval between the upper connecting wall 86 and the roller 28.

Further, the lower connecting wall 85 connects the support shaft 41 to the first
It is connected to the lower portion of the second support wall 31 ₂ in a position corresponding to the second recess 81 for accommodating by crimping the lower end of the pin 47 for securing to the drive rocker arm 19. In addition, the swing support portion 19 is provided between the lower connecting wall 85 and the upper connecting wall 86.
The surface of the roller a facing the roller 28 is formed in a curved shape corresponding to the outer peripheral surface of the roller 28.

The surface of the distal end connecting portion 19b facing the roller 28 has a curved surface corresponding to the outer peripheral surface of the roller 28, and is formed so that the distance from the roller 28 decreases as it goes downward. Thereby, in the portion corresponding to the lower half of the tappet screw 27 in the axial direction, the thickness of the tip connecting portion 19b in the direction orthogonal to the axis of the tappet screw 27 corresponds to the upper half of the tappet screw 27 in the axial direction. Is larger than the above thickness.

The surface of the second drive rocker arm 20 facing the roller 29 of the swing support portion 20a and the surface of the tip connecting portion 20b facing the roller 29 are the same as the swing support portion 19a and the tip of the first drive rocker arm 19. It is formed similarly to the connecting portion 19b.

Referring to FIG. 7, first and second support wall portions 3 are provided on the swing support portion 21a of the free rocker arm 21.
3 _1, 33 ₂ of the adjacent lower connecting wall 87 for connecting the base end lower portion in the lower outer peripheral surface of the roller 30, while being projected so as to face the first and second support walls 33 _1, 3
3 upper connecting wall 88 for connecting the _two proximal upper roller 3
The upper connecting wall 87 and the roller 30 are set to be smaller than the gap between the upper connecting wall 88 and the roller 30.

[0035] Moreover the lower connecting wall 87, the support shaft 43 a free pin 47 for fixing the rocker arm 21 the lower end of the second recess 81 first at a position corresponding to the support wall 33 ₁ for accommodating caulking while being connected to the lower, first at the portion corresponding to the receiving portion 62 which is protruded from the lower portion of the lost motion mechanism second in order to contact the 58 support wall 33 ₂ 2
It is connected to the support wall 33 _2. The surface of the swing support portion 21 a facing the roller 30 between the lower connecting wall 87 and the upper connecting wall 88 is formed in a curved shape corresponding to the outer peripheral surface of the roller 30.

The interlocking switching means 23 is connected to the first
Timing piston 63 capable of switching between interlocking and uncoupling of drive rocker arm 19 and free rocker arm 21
A cylindrical switching piston 64 capable of switching the interlocking and releasing of the free rocker arm 21 and the second drive rocker arm 20 adjacent to each other;
The switching member 64 includes a bottomed cylindrical regulating member 65 that contacts the switching piston 64 on the opposite side, and a return spring 66 that biases the regulating member 65 toward the switching piston 64.

The timing piston 63 is slidably fitted to the support shaft 41 of the first drive rocker arm 19, and has a first fitting hole 37 ₁ into which one end of the support shaft 41 is fitted.
A hydraulic chamber 67 is defined between the closed end of the piston and one end of the timing piston 63. In the rocker shaft 22, an oil passage 68 connected to a hydraulic pressure source via a control valve (not shown) is provided, for example, coaxially. Part 33 ₁
A communication hole 69 is provided in the rocker shaft 22 so that the communication passage 70 provided in the rocker shaft 22 is always communicated with the oil passage 68.

Referring to FIG. 8 as well, the communication path 70 is arranged in the direction in which the rocker arms 19 to 21 are arranged, that is, in this embodiment, in the direction along the axis of the rocker shaft 22 in the direction in which the rocker arms 19 to 21 are arranged. Each rocker arm 1 has a cross-sectional shape with a length in the direction orthogonal to
The first drive rocker arm 19 is provided on the first support wall portion 31 ₁ side so as to extend along a plane substantially orthogonal to the arrangement direction of 9 to 21, regardless of the swinging state of the first drive rocker arm 19. In order for the oil passage 68 to always communicate with the communication passage 70, the communication passage 70 is connected to the rocker shaft 22.
A communication hole 69 is provided in the rocker shaft 22 in a range larger in the circumferential direction of the rocker shaft 22 than in a range facing the outer surface of the rocker shaft 22. In addition, the other end of the communication passage 70 is open to the side of the first drive rocker arm 19, and an intermediate portion of the communication passage 70 is blocked by the rocker shaft 22.

Referring to FIG. 9 as well, in the first drive rocker arm 19, a bulging portion 19c bulging outward to form the communication passage 70 is formed on the outer surface on one end side in the arrangement direction of the rocker arms 19 to 21. Are provided between the side edge 19d of the outer surface of the first drive rocker arm 19 and the bulging portion 19c.
71 are provided.

The communication passage 70 has a part that extends in a direction parallel to the axis of the rocker shaft 22.
So that it is located closer to the roller 28 than one end of the first
The drive rocker arm 19 is provided with a notch 72 having a shape corresponding to the communication passage 70 at a portion corresponding to the communication passage 70 at one end of the support shaft 41.
That is, the hydraulic oil flowing through the communication passage 70 is guided to the hydraulic chamber 67 without being interrupted by the support shaft 41.

The switching piston 64 is connected to the free rocker arm 21.
And one end of the switching piston 64 is brought into contact with the other end of the timing piston 63 so as to be able to slide on each other.

The restricting member 65 is formed in a cylindrical shape with a bottom and is slidably fitted to the support shaft 42 of the second drive rocker arm 20. The other ends are allowed to contact each other, allowing them to slide. A retaining ring 73 is mounted on the inner surface of the support shaft 42 so as to abut against the control member 65 and prevent the control member 65 from dropping off the support shaft 42. Return spring 66
Corresponds to the second fitting hole 38 in the second drive rocker arm 20.
₂ between the closed end of the _second and the regulating member 65,
The closed end of the fitting hole 38 ₂ open pores 74 are drilled.

In the interlocking switching means 23, in the low-speed operation range of the engine, the hydraulic pressure in the hydraulic chamber 67 is relatively low, and the timing piston 63 and the switching piston 64
Is located at a position corresponding to between the first drive rocker arm 19 and the free rocker arm 21, and the switching piston 64
The contact surface of the regulating member 65 is located at a position corresponding to between the free rocker arm 21 and the second drive rocker arm 20. Therefore, each rocker arm 19, 20, 21 is in a state in which it can relatively swing, and both intake valves VI are driven to open and close at the timing and the lift amount corresponding to the low-speed valve cams 25, 25.

In the high-speed operation range of the engine, a relatively high hydraulic pressure is applied to the hydraulic chamber 67 so that the timing piston 6
3 is fitted to the support shaft 43 of the free rocker arm 21 while pressing the switching piston 64, and the switching piston 64 presses the regulating member 65 while supporting the support shaft 4 of the second drive rocker arm 20.
2 is fitted. Therefore, each rocker arm 19, 20,
21 are connected integrally, and the two intake valves VI ...
Is driven to open and close at a timing and a lift amount corresponding to the high-speed valve operating cam 26.

[0045] Referring also to FIGS. 10 and 11, two support walls 33 _1, 33 side receiving portion 62 of the _two is provided in the free rocker arm 21, i.e. the second support wall portions 33
The _2, provided so as lubricating oil passage 76 communicating at all times to the oil passage 68 of the rocker shaft 22 is opened to one end to the second fitting hole 39 ₂ of the inner surface, the second fitting hole 39 ₂ of the inner surface Is provided with a groove 77 having one end connected to one end of the lubricating oil passage 76 and the other end opened to the bearing 55 side.

Further, the lubricating oil passage 76 has a cross section in which the length in the direction substantially perpendicular to the arrangement direction of the rocker arms 19 to 21 is larger than the length in the direction substantially parallel to the arrangement direction of the rocker arms 19 to 21. The lubricating oil passage 76 is formed so as to be always in communication with the lubricating oil passage 76 regardless of the swinging state of the free rocker arm 21. A communication hole 78 is provided in the rocker shaft 22 in a large range in the circumferential direction of the shaft 22. The other end of the lubricating oil passage 76 is open to the side of the free rocker arm 21, and an intermediate portion of the lubricating oil passage 76 is blocked by the rocker shaft 22.

The rocker arms 19, 2
Reference numerals 0 and 21 are formed by metal injection molding. Thus, in performing metal injection molding, a step of kneading a binder such as a raw material powder and a wax, a step of granulating the compound obtained in the kneading step to obtain a pellet, and injecting the pellet in a mold. Molding and shaping, heating the shaped product to remove the binder,
The steps of performing the sintering process may be sequentially performed.

12 and 13, the cylinder head 11 is set so as to face the center of the combustion chamber 90 of each cylinder.
A mounting hole 92 for mounting the ignition plug 91 is provided in the cylinder head 11, and a spark plug insertion cylinder 93 extending upward through the mounting hole 92 is mounted on the cylinder head 11. Can be

Above the cylinder head 11, an intake-side valve train 17 for opening and closing the pair of intake valves VI, VI is provided.
An exhaust valve operating device 17E for opening and closing the pair of exhaust valves VE and VE is disposed so as to sandwich the spark plug insertion cylinder 93 therebetween. Moreover, the exhaust side valve train 1
7E has the same configuration as the intake-side valve operating device 17I.
Corresponding parts of 7I and the exhaust-side valve train 17E are denoted by the same reference numerals, and are only shown in the drawing, and detailed description of the exhaust-side valve train 17E is omitted.

The ignition plug insertion cylinder 93 is disposed between the free rocker arms 21 and 21 of the intake-side valve train 17I and the exhaust-side valve train 17E, respectively.
A notch 94 that is recessed on the opposite side of the ignition plug insertion tube 93 is provided in a portion of the swing support portion 21a of the free rocker arms 21 that faces the ignition plug insertion tube 93.

The notch 94 is formed so as to be curved in correspondence with the outer peripheral surface of the ignition plug insertion cylinder 93 having a circular cross section. The radius of curvature of the notch 94 is equal to that of the outer surface of the ignition plug insertion cylinder 93. It is set larger than the radius. Moreover, the notch 94 is provided at the center of the swing support portion 21 a in the direction along the axis of the rocker shaft 22, and has the deepest portion of the notch 94 (the center of the ignition plug insertion cylinder 93) and the free rocker arm 21. The part of the roller 30 (preferably, the axial center of the roller 30 as in this embodiment) supported by the roller 30 is disposed on the same plane orthogonal to the rotation axis of the free rocker arm 21, that is, the axis of the rocker shaft 22. You.

The notch 94 is provided in the opening 3 provided in the free rocker arm 21 for accommodating the roller 30.
6, that is, the first in the free rocker arm 21.
And a portion corresponding to the portion between the second support wall portions 33 ₁ and 33 ₂ , provided on the swing support portion 21 a, and notches 94 at both ends of the swing support portion 21 a along the axis of the rocker shaft 22. Arc-shaped bulging portions 95, 95 bulging outward so as to be sandwiched between them are formed.

The second support wall 33 of the free rocker arm 21
The _second, although the lubricating oil passage 76 communicating at all times to the oil passage 68 of the rocker shaft 22 is provided so as to open the one end to the second fitting hole 39 ₂ of the inner surface, the other of the lubricating oil passage 76 The end is opened on the outer surface of one of the bulges 95, 95 so as to be arranged at a position off the notch 94 along the axis of the rocker shaft 22.

Further, a lower connecting wall 87 connects the lower portions of the support walls 33 ₁ and 33 ₂ of the free rocker arm 21 at a lower end thereof, and an upper portion connects the upper ends of the support walls 33 ₁ and 33 _2. Although connected by a wall 88, at least a part (all in this embodiment) of the notch 94 and at least a part of the lower connecting wall 87 (in this embodiment, the center of the lower and upper connecting walls 87, 88). Is the swing axis of the free rocker arm 21, that is, the rocker shaft 22.
Are arranged on the same plane that is orthogonal to the axis.

[0055] Also on the outer surface of the two support walls 33 _1, 33 ₂ parts of the swing support portion 21a closer in the free rocker arm 21 is provided with a groove extending vertically, these grooves, the mutually adjacent 1st drive between the rocker arm 19 and the free rocker arm 21 and the second
Between the drive rocker arm 20 and the free rocker arm 21, oil grooves 96, 96 having upper ends opened at the upper portions of the respective rocker arms 19 to 21, are formed.

Next, the operation of this embodiment will be described. Each of the rocker arms 19 to 21 has a support shaft 41 to rotatably support rollers 28 to 30 for reducing a valve operating load.
While 43 is fixed, both ends of the support shafts 41 to 43, the first fitting hole 37 _1, 3 the rocker arms 19 to 21 are provided
8 _1, 39 ₁ and second fitting holes 37 _2, 38 _2, 39 ₂
Respectively. Also, the first drive rocker arm 19
The second support wall 31 ₂ pin 47 which is inserted into the insertion hole 44 provided in the is engaged with the engaging groove 50 of the support shaft 41, the second
Pin 48 which is inserted into the insertion hole 45 provided in the first support wall 32 ₁ of the driving rocker arm 20 is engaged with the engaging groove 51 of the support shaft 42, the first support wall 33 ₁ of the free rocker arm 21 The pins 49 inserted into the insertion holes 46 provided are engaged with the engagement grooves 52 of the support shafts 43 so that the shafts 41 to 43 are prevented from moving in the axial direction and rotating around the axes. Therefore, the support shafts 41 to 43 can be fixed to the respective rocker arms 19 to 21 with a simple structure.

Each pin 47 to 49 is connected to the corresponding rocker arm 1
When fixing to pins 9 to 21, both ends of each of pins 47 to 49 inserted into insertion holes 44 to 46 are caulked, so that even if pins 47 to 49 have a small diameter,
The fixing work is easier than the press-fitting, the workability is improved, and the pins 47 to 49 can be securely fixed to the rocker arms 19 to 21.

Further, each of the pins 47 to 49 is not press-fitted, but is inserted into each of the insertion holes 44 to 46. The inner diameter of each of the insertion holes 44 to 46 is smaller than the outer diameter of each of the pins 47 to 49. The width of each of the engagement grooves 50 to 52 may be set to have a relatively large margin with respect to the diameter of each of the pins 47 to 49. Then, each pin 47-49 can be inserted into each of the insertion holes 44-49 without strictly setting the circumferential position of each support shaft 41-43.
46, it is easy to engage with each of the engagement grooves 50 to 52, and each rocker arm 19 to 2 of each pin 47 to 49
1 can be easily fixed.

Both ends of each of the pins 47 to 49 are flat punches 8.
Since the diameters of the flat punches 82 and 83 are set to be larger than the diameters of the pins 47 to 49, even if the positions of the flat punches 82 and 83 with respect to the pins 47 to 49 are slightly shifted. The pins 47 to 49 can be securely caulked, and the rigidity of the caulked portion does not decrease due to the displacement of the caulking position. Moreover, the insertion holes 44 to 46
, And flat punches 82, 8 in recesses 80, 81.
Are set larger than the outer diameters of the flat punches 82, 83 so as to accommodate
By caulking the both ends of the pins 47 to 49 in the concave portions 80, 81, the caulked portions do not protrude from the outer surfaces of the rocker arms 19 to 21.
Are provided, the insertion holes 44 to 46, that is, the pins 4 are provided.
7 to 49 can be shortened, and the intermediate portion of the pins 47 to 49 is prevented from being deformed by caulking as much as possible, and the positioning accuracy of the shafts 41 to 43 by the pins 47 to 49 is improved. And rocker arm 1
Rocker arms 19-21 to reduce overall weight
The inertia weight of the internal combustion engine can be reduced, and it is possible to advantageously cope with high-speed rotation of the internal combustion engine.

[0060] By further portion which engages at least the engaging groove 50 to 52 of the pin 47 to 49 is relatively high hardness (induction hardening region) (e.g. H _V 579~832), the pins 47-49 Wear Shaft 4 to prevent deformation and
1 to 43 can be reliably positioned, and the pins 47 to 4
9 will be improved caulking accuracy becomes easy crimping the end portions is relatively low hardness (not quenched region) (e.g. H _V 180 to 260) that the.

The first drive rocker arm 19 has an oil passage 68 of the rocker shaft 22 and a hydraulic chamber 67 of the interlocking switching means 23.
Is provided so as to extend in a plane substantially orthogonal to the arrangement direction of the rocker arms 19 to 21. The communication passage 70 is connected to the rocker arms 19 to 21.
Has a cross-sectional shape in which the length in a direction substantially perpendicular to the arrangement direction of the rocker arms 19 to 21 is larger than the length in a direction substantially parallel to the arrangement direction. Accordingly, the communication path 7 is parallel to the direction in which the rocker arms 19 to 21 are arranged.
The space occupied by 0 can be reduced as much as possible, and the first drive rocker arm 19 can be reduced in size accordingly.

[0062] Moreover in the first driving rocker arm 19, the first fitting hole 37 one end portion of the support shaft 41 of the first support wall 31 _1
1 and the support shaft 41 is attached to the first drive rocker arm 1.
Although 9 than it is secured to, by the communication passage 70 is provided in the first driving rocker arm 19 in the first support wall portion 31 ₁ side, a first support for fixing the support shaft 41 supporting the rollers 28 it is possible to arrange the communication passage 70 in the first driving rocker arm 19 to avoid that the wall portion 31 ₁ of the thickness is increased. Moreover, a notch 72 having a shape corresponding to the communication passage 70 is provided at a portion corresponding to the communication passage 70 at one end of the support shaft 41, so that the first support wall portion 31 ₁ of the first drive rocker arm 19 is provided. the first support shaft 41 is sufficiently secured contact area of the support shaft 41 of the first fitting hole 37 ₁
The communication path 70 can be arranged closer to the roller 28 side while securing the support strength to the drive rocker arm 19, so that the size of the first drive rocker arm 19 can be further reduced.

As described above, the first drive rocker arm 19 can be downsized, so that in the multi-cylinder internal combustion engine as in this embodiment, the cylinder head 11 can be greatly downsized.

A communication passage 7 is provided on the outer surface of one end of the first drive rocker arm 19 along the axial direction of the rocker shaft 22.
0, and a bulging portion 19c bulging outward is provided, and ribs 71, 71 connecting the side edge portion 19d of the outer surface and the bulging portion 19 are provided. It is possible to reduce the weight of the first drive rocker arm 19 while securing the rigidity of the first drive rocker arm 19.

Further, the communication path 70 is provided on the first support wall 31 ₁ side of the first drive rocker arm 19,
The roller 28 in the second support wall 31 ₂ sandwiched between the first support wall 31 _1, since the insertion holes 44 for fixing the support shaft 41 is provided, avoiding an increase in size of the first driving rocker arm 19 As a result, a space for providing the insertion hole 44 can be secured, and the insertion hole 44 is provided at a position relatively distant from the communication passage 70 which is a cavity, which is advantageous in terms of rigidity of the first drive rocker arm 19.

In the free rocker arm 21, the second fitting hole 3
9 ₂ of the inner surface is opened at one end lubricating oil passage 76 is provided in communication with the oil passage 68 of the rocker shaft 22, the second fitting hole 3
9 ₂ of the inner surface, the groove 77 was allowed open at the other end to the needle bearing 55 side together providing communication at one end thereof to one end of the lubricating oil passage 76 is provided, via the lubricating oil passage 76 and the groove 77 from the oil passage 68 needle bearing Te lubricating oil would be oil to the needle bearing 55, a simple structure of only grooves 77 in the second fitting hole 39 ₂ of the inner surface with the lubricating oil passage 76 is provided is provided in the free rocker arm 21 55 can be refueled. Therefore, it is not necessary to perform a drilling process for guiding the lubricating oil to the support shaft 43, and there is no possibility that the rigidity of the support shaft 43 is reduced, and the number of processing steps is reduced.

The free rocker arm 21 is driven by the high-speed valve cam 26 having a cam profile for high-speed operation of the engine, and has a relatively large inertial weight and a relatively large load on the needle bearing 55. However, the needle bearing 55 has a simple structure as described above.
Lubricating oil can be supplied effectively, and the load acting on the needle bearing 55 can be reduced.

Further, the lubricating oil passage 76 has a cross-sectional shape in which the length in a direction substantially perpendicular to the arrangement direction of the rocker arms 19 to 21 is larger than the length in a direction substantially parallel to the arrangement direction of the rocker arms 19 to 21. The space occupied by the lubricating oil passage 76 in the direction parallel to the arrangement direction of the rocker arms 19 to 21 can be minimized, and the free rocker arm 21 can be reduced in size. Accordingly, the size of the cylinder head 11 of the multi-cylinder internal combustion engine can be reduced.

[0069] Also in the free rocker arm 21, the lubricating oil passage 76 is an insertion hole 46 for fixing the support shaft 43 with respect to the provided second support wall 33 ₂ side first support wall portion 33
Since it is provided on the _one side, it is possible to secure a space for providing the insertion hole 46 while avoiding an increase in the size of the free rocker arm 21, and the insertion hole 44 is provided at a position relatively far from the lubricating oil passage 76 which is a cavity. Since it is provided, the rigidity of the free rocker arm 21 is also advantageous.

The free rocker arm 21 has a receiving portion 62 which comes into contact with the lifter 60 of the lost motion mechanism 58. The receiving portion 62 is provided with the second support wall portion 33 _2.
The rocker arm 21 is provided integrally with the lower portion of the free rocker arm 21 so that the receiving portion 62 is arranged beside the roller 30.
Can be simplified, the size of the free rocker arm 21 can be prevented from being increased, and the inertial weight of the free rocker arm 21 can be reduced to advantageously cope with high-speed rotation of the internal combustion engine.

[0071] Moreover whereas the support shaft 43 is fixed by a pin 49 in the first support wall portion 33 ₁ side, receiving unit 62 second
Since it is provided on the support wall 33 _2, inserting the pin 49, without being limited by the size and arrangement receiving part 62 of the insertion hole 46 for fixing, and load from the lost motion mechanism 58 to the pin 49 The support shaft 43
Can be increased in fixing strength. In addition, since the receiving portion 62 is provided integrally with the ₂ second support wall portion 33, even though the lubricating oil passage 76 is hollow is provided in _two second support wall portion 33, the second support it is possible to avoid a decrease in rigidity of the wall portion 33 _2, a lubricating oil passage 76
Two support walls 3 but as supplement accompanied second weight loss of the support wall portion 33 ₂ to be hollow in the receiving portion 62 the
3 _1, 33 ₂ of the weight balance can be improved.

Further, the free rocker arm 21 is
3 inserted first support wall 33 with a hole 46 is provided ₁ for fixing the can is supported on the rocker shaft 22 so as to be disposed side first driving rocker arm 19, the second driving rocker arm 20, the support shaft 42 Insertion hole 45 for fixing
Are those in which the first support wall 32 ₁ provided supported on the rocker shaft 22 so as to be disposed side first driving rocker arm 19, the timing piston 63 and the switching piston 64 of the interlocking switching means 23 is inserted Since the support shafts 43 and 42 are fixed to the free rocker arm 21 and the second drive rocker arm 20 on the side of the
64 is smoothly inserted into the support shafts 43 and 42, and the interlocking switching operation of the interlocking switching means 23 is smoothed.

By the way, each of the rocker arms 19 to 21
And those formed by metal injection molding, it is possible to form the communication passage 70, both the fitting holes 37 _1, 37 ₂ and the insertion hole 44 is not a perfect circle at the same time as the formation of the first driving rocker arm 19, the second At the same time as the formation of the drive rocker arm 20, both the fitting holes 38 ₁ and 38 ₂ , the insertion hole 45 and the opening hole 74 can be formed. Holes 39 ₁ , 39 ₂
And the insertion hole 46 can be formed. Therefore, the post-processing of each of the rocker arms 19 to 21 can be minimized to improve the productivity.

In each of the rocker arms 19 to 21,
The rocker arms 19 to 21 are provided on the rocking support portions 19a to 21a which are rockably supported by the rocker shaft 22.
A pair of support wall portions 31 ₁ , 31 ₂ ; 32 ₁ , 32
₂ ; the roller 28 is connected by connecting the lower portions of the base ends of 33 ₁ and 33 _2.
Lower connecting wall 85 close to and facing the lower outer peripheral surface of
, 87 are projected, and the support wall portions 31 ₁ , 31
_2; 32 _1, 32 _2; 33 _1, 33 near the _inter-2 of the base end upper on the upper outer peripheral surface of the linked rollers 28-30, upper connecting wall 86 facing ..., since 88 is projected, a lower The surfaces of the swing support portions 19a to 21a facing the rollers 28 to 30 are formed in a curved shape between the connection walls 85 ... 87 and the upper connection walls 86 ... 88, so that both support wall portions 3 are formed.
1 _1, 31 _2; 32 _1, 32 _2; 33 _1, 33 ₂ rocker arm 19-21 can increase the rigidity of the entire it becomes possible to increase the supporting rigidity of the support shaft 41 to 43 by the rigidity increases Weight increase due to the curved surface can be avoided as much as possible.

The lower connecting walls 85 and 87 and the upper connecting walls 86 and 88 are arranged by effectively utilizing the space between the rollers 28 to 30 and the swing support portions 19a to 21a. The rockers 19 to 21 are not enlarged by the walls 85... 87 and the upper connecting walls 86.

The lower connecting walls 85...
The lower connecting wall 85
, 87 and the rollers 28 to 30 can be temporarily held, and the oil held between the lower connecting walls 85.
30 and needle bearing 53 between support shafts 41 to 43
To 55, the rotational resistance of the rollers 28 to 30 can be reduced. At this time, the distance between the lower connecting walls 85... 87 and the rollers 28 to 30 corresponds to the upper connecting walls 86.
88 and the distance between the rollers 28 to 30 are set smaller than the distance between the lower connecting wall 85 and the oil from above.
, 87 and the rollers 28 to 30 can be effectively guided. The hit load received from the valve operating cams 25..., 26 disposed above the support shafts 41 to 43 is
The lower connecting wall 8 is larger in the lower part than in the upper part of.
5, 87 support wall portions 31 ₁ , 31 ₂ ; 32 ₁ , 32 ₂ ; 33 ₁ , 3 for supporting the lower portions of the support shafts 41 to 43.
3 since ₂ reinforces the bottom, the support walls 31 _1, 3
1 _2; 32 _1, 32 _2; 33 _1, 33 ₂ which is advantageous for enhancing the rigidity.

Further, the first and second drive rocker arms 1
In FIGS. 9 and 20, the surface of the tip connecting portions 19b and 20b facing the rollers 28 and 29 has a curved shape corresponding to the outer peripheral surface of the rollers 28 and 29, and the roller 2 moves downward.
Since it is formed so that the interval between 8, 29 is small,
The oil is also effectively held in the lower portion between the rollers 28, 29 and the tip connecting portions 19b, 20b, and the rollers 28, 29
The rotational resistance can be further reduced,
At the portion corresponding to the lower half of the tappet screws 27 in the axial direction, the thickness of the distal end connecting portion 19b in the direction orthogonal to the axis of the tappet screws 27 is increased to increase the support rigidity of the tappet screws 27. it can.

Further, since the rocker arms 19 to 21 are formed by injection molding of metal, the lower connecting walls 85, 87 and the upper connecting walls 86, 88 project from the swing support portions 19a to 21a. A complicated structure can be easily formed, and rocker arms 19a to 21a having optimum shapes in consideration of an increase in rigidity and a reduction in weight can be easily formed.

Further, in each of the rocker arms 19 to 21, a second recess 81 which faces the lower ends of the pins 47 to 49 for fixing the support shafts 41 to 43 is provided with lower connecting walls 85.
The supporting wall portions 31 ₂ , 32
Since open to _1, 33 ₁ of the lower surface, a second recess 81 ...
The support wall portions 31 ₂ , 32 ₁ , 33
The rigidity reduction of ₁ can be suppressed as much as possible.

[0080] On the other hand, the receiving portion 62 provided in the free rocker arm 21 so as to abut against the lost motion mechanism 58, since it is arranged in _two second support wall portion 33 continuous with the one end of the lower connecting wall 87, lost motion The rigidity of the receiving portion 62 to which a load is applied from the mechanism 58 can be increased by the lower connecting wall 87.

The rocking support portions 21 of the free rocker arms 21.
a in the portion facing the spark plug insertion cylinder 93,
A notch 94 is provided on the side opposite to the spark plug insertion tube 93. Therefore, the spark plug insertion cylinder 93 and the free rocker arm 21 can be arranged as close as possible, and the valve operating chamber formed in the internal combustion engine to accommodate the intake-side and exhaust-side valve operating devices 17I and 17E can be downsized. In addition, it is possible to contribute to weight reduction of the free rocker arm 21. In addition, at least a part of the notch 94 (all in this embodiment) and at least a part of the lower connecting wall 87 (the center of the lower and upper connecting walls 87 and 88 in this embodiment) are aligned with the axis of the rocker shaft 22. The lower connecting wall 87 and the upper connecting wall 88 make it possible to compensate for the reduction in rigidity of the swing support portion 21a due to the provision of the notch 94 because they are arranged on the same plane orthogonal to each other.

The notch 94 is formed so as to be curved in accordance with the outer peripheral surface of the ignition plug insertion cylinder 93 having a circular cross section, so that the rigidity of the free rocker arm 21 is prevented as much as possible while preventing the free rocker arm 21 from being lowered. Can be brought closer to the spark plug insertion tube 93. Further, since the radius of curvature of the notch 94 is set to be larger than the radius of the outer surface of the spark plug insertion tube 93, the free rocker arm 21 is ignited while avoiding mutual interference between the swinging free rocker arm 21 and the spark plug insertion tube 93. Plug insertion tube 93
Accordingly, it is possible to make the free rocker arms 21 closer to each other, and it is possible to suppress a decrease in rigidity of the free rocker arm 21 due to the formation of the notch 94.

The deepest part of the notch 94 and a part of the roller 30 supported by the free rocker arm 21 (preferably, the axial center of the roller 30 as in this embodiment) are orthogonal to the axis of the rocker shaft 22. The free rocker arm 2 is located on the same plane
1 within the width of the opening 36 provided in the swing support portion 21.
a, the notch 94 is provided, so that the load from the intake valve VI or the exhaust valve VE and the high-speed valve cam 2
The notch 94 is arranged at a position deviated from a portion where the load from the load 6 acts on the free rocker arm 21, and even if the rigidity of the free rocker arm 21 is reduced by the formation of the notch 94, the entire free rocker arm 21 is formed. As a result, sufficient rigidity can be maintained.

Further, at both ends of the rocking support portion 21a along the axis of the rocker shaft 22, arc-shaped bulging portions 95, 95 bulging outward with the notches 94 interposed therebetween are formed. The swelling portion 9 reduces rigidity reduction due to the notch 94
5, 95, and the two supporting wall portions 33 ₁ , 33 _{2 on which} the load from the intake valve VI or the exhaust valve VE and the load from the high-speed valve cam 26 act the most.
Can be increased by the bulging portions 95, 95.

A lubricating oil passage 76 which always communicates with the oil passage 68 of the rocker shaft 22 is opened on the outer surface of the rocking support portion 21a, and the lubricating oil passage 76 is displaced from the notch 94 along the axis of the rocker shaft 22. Since the oil passage 76 is provided, the rigidity of the swing support portion 21a does not decrease even when the opening of the lubricating oil passage 76 and the notch 94 are formed.

Further, between the first drive rocker arm 19 and the free rocker arm 21 adjacent to each other and between the second drive rocker arm 20 and the free rocker arm 21 adjacent to each other, the oil having the upper end opened at the upper part of each rocker arm 19 to 21 is provided. Since the grooves 96 are formed, it is not necessary to provide a special oil passage, and lubrication between the rocker arms 19, 21; 20, 21 can be performed by the scattered oil in the valve operating chamber.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

For example, in the above-described embodiment, the valve gear having the rocker arm supported to be rockable by the rocker shaft 22 has been described.
As disclosed in Japanese Patent Publication No. 0916, the present invention is also applicable to a valve gear in which one end of a rocker arm is pivotally supported by a pivot. The present invention also relates to the interlocking and interlocking of a plurality of rocker arms 19 to 21. Regardless of the presence or absence of the interlock switching means 23 capable of switching the release, the present invention can be widely applied to a valve operating device of an internal combustion engine in which a rocker arm is interlocked and connected to a valve operating cam via a roller.

The present invention can also be applied to a structure in which pins 47 to 49 for fixing the support shafts 41 to 43 are pressed into the respective rocker arms 19 to 20. In this case, the pins 47 to 49 are used. By connecting the lower connecting wall to the lower fixing portion, the rigidity of the rocker arms 19 to 21 receiving the press-fitting load when the pins 47 to 49 are press-fitted can be contributed. Further, the support member 22
The support member 22 may be provided directly on the cylinder head 11 or may be supported by a holder provided on the cylinder head 11.

[0090]

As described above, according to the first aspect of the present invention,
The distance between the base ends of the pair of support walls of the free rocker arm is
Because are connected by parts connecting wall and the lower connecting wall, to increase the support rigidity of the support shaft by the two support walls, the rigidity of the entire free rocker <br/> over arm can also be increased further lower connecting wall and Ri possible and Do to reduce the rotational resistance of the roller as possible to temporarily hold the oil between the rollers, the teeth
The upper connecting wall and the lower connecting wall do not increase the size of the rocker arm.

The hit load received from the valve operating cam is
Although the lower part is larger than the upper part of the
Is particularly due to the lower connecting wall, which
To reinforce the lower part of both support walls that support the lower part of the support shaft.
This is advantageous for improving the rigidity of both support walls.
And a pressing means for urging the free rocker arm
Both ends connected to one end of the lower connecting wall along the axis of the shaft
Being in contact with the receiving part protruding from one lower part of the wall
This reduces the rigidity of the receiving part where the load acts from the pressing means.
It can be enhanced by the connecting wall.

According to the second aspect of the present invention, the spark plug insertion cylinder and the rocker arm can be arranged as close as possible to contribute to downsizing of the valve operating chamber and weight reduction of the rocker arm. It is possible to compensate for the lowering of the rigidity of the swing support portion due to the lower connecting wall.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a part of a valve train, and is a sectional view taken along line 1-1 of FIG. 2;

FIG. 2 is a plan view as viewed in the direction of arrow 2 in FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG. 2;

FIG. 6 is a cross-sectional view corresponding to FIG. 5 in a state before the pins are swaged.

FIG. 7 is a sectional view taken along line 7-7 of FIG. 2;

FIG. 8 is a sectional view taken along line 8-8 in FIG. 4;

FIG. 9 is a sectional view taken along line 9-9 of FIG. 2;

FIG. 10 is a sectional view taken along line 10-10 of FIG. 4;

FIG. 11 is a sectional view taken along line 11-11 of FIG. 10;

FIG. 12 is a plan view of the intake-side and exhaust-side valve trains.

FIG. 13 is a sectional view taken along line 13-13 of FIG. 12;

[Reference Numerals] VI ... engine intake valve as valve 17I, 17E ... valve system 18 ... cam shaft 19, 2 0 ... first, second driving rocker arm 21 ... free rocker arm 19a, 20a, 21a ... rocker shaft 25, 26 ... valve operating cam 28, 29, 30 ... roller 31 ₁ of the swing support portions 22 ... support member, 31 _2, 32 _1, 32 ₂ , 33 ₁ , 33 ₂ ...
Support wall portions 41, 42, 43 support shafts 44, 45, 46 insertion holes 47, 48, 49 pins 50, 51, 52 engagement grooves 53, 54, 55 ..Bearing 58 ... Lost motion mechanism as pressing means 87 ... Lower connecting wall 88 ... Upper connecting wall 93 ... Ignition plug insertion tube 94 ... Notch

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mamoru Kosuge 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Technical Research Institute Co., Ltd. (56) References JP-A-63-100211 (JP, A) 5-65813 (JP, A) JP-A-11-200822 (JP, A) JP-A-10-43833 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 13/00 301 H01L 1/18

Claims (2)

(57) [Claims] (1)Multiple rockers arranged adjacent to each other
(19, 20, 21) and their rocker arms (1
9, 20, 21)Valve cam (25,
A camshaft (18) provided with 26);Each rocker
Turn off and on the arms (19, 20, 21)
Switchable interlock switching means (23).
The hook arm (19, 20, 21) is connected to the engine valve (VI).
Drive rocker arms (19, 20) linked and connected,
When the interlocking switching means (23) is released from interlocking, the engine valve (V
A free rocker arm (21) that is free to I)
Including the free rocker arm (21)Cylinder head
Swingable by a support member (22) provided on the arm (11).
Supported swing support (21a) includes the swing support portion (21
a) opposing each other at intervals in the direction along the swing axis
A pair of support walls (33₁, 33_TwoThe base end of
EstablishedBecomeThe two support walls (33₁, 33_Two)Between
Supported shaft (43)Has a free rocker arm (2
Rock 1)Valve operated cam (26) Rolling contact
roller(30)Is rotatable via bearing (55)
Supported by,A valve gear for an internal combustion engine,Both support walls (33 ₁ , 33 _Two )
The upper connecting wall (88) is located outside the upper part of the roller (30).
The swing support portion (21a) is opposed to the peripheral surface.
While being protruded,Both support walls (33₁, 33_Two)of
Connect between lower basesAnd projecting beyond the upper connecting wall (88).
Large outputLower connecting wall (87) is the roller (3
0) The swing support portion is opposed to the outer peripheral surface of the lower portion.
(21a), Rolling contact of said roller (30) with valve cam (26)
Push to bias free rocker arm (21) in the direction
A pressure means (58) extends along the axial direction of the support shaft (43).
The two supporting walls are connected to one end of the lower connecting wall (87).
Part (33 ₁ , 33 _Two ) (33 _Two Protruding from the bottom)
Contacting the receiving part (62) Characterized by the following
Valve train for fuel engine. 2. A cylinder head swing support part of the at a portion facing the spark plug insertion tube attached to (11) (93) freely b <br/> Kkaamu (21) to (21a), the spark plug Notch (94) recessed on the opposite side to insertion tube (93)
It is provided, and at least a portion of said lower connecting wall (87), at least a portion of said notch (94) is, the self
The valve train of an internal combustion engine according to claim 1, characterized in that the valve train is arranged on the same plane orthogonal to the swing axis of the free rocker arm (21).