JP6187642B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine.

  2. Description of the Related Art Conventionally, as a variable valve operating apparatus for an internal combustion engine, one that uses a so-called lost motion mechanism that changes a lift amount by changing a phase of a swing cam with respect to a valve is known (see, for example, Patent Document 1). In such a variable valve system, the vicinity of the tip of the cam crest becomes a valve-driven region as the intake valve shifts from a large lift amount state to a small lift amount state. Since the tip region of the cam crest has a small lift amount with respect to the working angle, the value of the ratio between the valve lift amount and the working angle (valve lift amount / working angle) becomes small. For this reason, the valve lift amount with respect to the change of the piston position in the intake process is small, and even if the throttle is fully opened, the valve opening region (area) of the intake valve cannot be secured sufficiently, and the effect of reducing the pump loss is reduced.

  On the other hand, an internal combustion engine having a variable valve mechanism that drives a compressed fluid chamber with a cam or the like and lifts a valve with hydraulic pressure is known (for example, see Patent Document 2). In this variable valve mechanism, the ratio of the valve lift amount to the working angle (valve lift amount / working angle) can be made larger than in the case of the above-described lost motion mechanism.

JP 2001-263015 A JP 2005-201259 A

  However, in the variable motion mechanism disclosed in Patent Document 2, the engine oil or the like, which is a viscous fluid, is supplied to the hydraulic piston through the hydraulic passage, and the valve is operated by the stroke of the hydraulic piston. Sometimes pressure loss occurs due to the resistance of the hydraulic passage, and there is a problem that friction loss increases.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a variable valve operating apparatus for an internal combustion engine that reduces pump loss of the internal combustion engine and reduces friction loss when the valve is driven. .

  In order to solve the above-described problems and achieve the object, one aspect of the present invention is a rocker arm that is pivotally supported by a support shaft and that opens and closes an intake valve in accordance with the rocking motion. Fixed to a swinging arm having a first contact portion and a second contact portion at a position sandwiching the rotation shaft, and a camshaft disposed in the vicinity of the first contact portion. The cam has a cam that allows the intake valve to lift by contacting the first contact part, and a projecting / retracting part that contacts the second contact part. A hydraulic actuator that includes a hydraulic chamber to be driven, and reduces the volume of the hydraulic chamber and retracts the retracted portion while the intake valve is lifted by the cam crest of the cam, and closes the intake valve at an arbitrary timing; It is characterized by providing.

  One embodiment of the present invention includes a cylinder head that supports a camshaft, and a detected portion at a position that is provided on the cylinder head and faces a detected portion that is provided at an end portion on the support shaft side of the rocker arm. It is preferable to include a gap sensor that detects the distance of the oil pressure, an oil relief passage that communicates with the hydraulic chamber, and a solenoid valve that is controlled to open and close the oil relief passage based on an output signal of the gap sensor.

  The variable valve operating apparatus for an internal combustion engine according to the present invention can reduce the pump loss of the internal combustion engine and reduce the friction loss when the valve is driven.

FIG. 1 is a perspective view of a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of a main part of the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention. FIG. 3 is a cross-sectional view of the hydraulic actuator in the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention. FIG. 4 is a cross-sectional view of the oil reserve tank in the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention. FIG. 5 shows a non-lift state when the base circle portion of the cam is in contact with the first input roller (first contact portion) in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention. FIG. FIG. 6 is a front view showing a state where the maximum lift amount is selected and the lift amount is maximized in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention. FIG. 7 is a front view showing a state where the minimum lift amount is selected and the lift amount is minimized in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention. FIG. 8 is a front view showing a state where the minimum lift amount is selected and the intake valve is quickly closed in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention. FIG. 9 is a case where the minimum lift amount is obtained in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention, and the state when the nose portion of the cam passes through the first input roller (first contact portion). FIG. FIG. 10 is a cross-sectional view showing that the tappet (protruding portion) of the hydraulic actuator is in the protruding state in the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention. FIG. 11 is a cross-sectional view showing a state where the tappet (protruding part) of the hydraulic actuator is submerged in the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention. FIG. 12 is a cross-sectional view showing a state in which the oil relief passage is closed while the tappet (protruding part) of the hydraulic actuator is submerged in the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention. FIG. 13 is a cross-sectional view showing a state in which the tappet (protruding portion) protrudes again after the intake valve is closed in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention. FIG. 14 shows (1) valve lift characteristics when the minimum lift amount is selected, (2) valve lift characteristics indicating early closing control when the maximum lift amount is selected, and (3) maximum lift amount is selected. Valve lift characteristics (full lift curve), and (4) a valve lift characteristic diagram showing a valve lift characteristic when a minimum lift amount is selected using a conventional lost motion mechanism, and (1) to (3 2) is a diagram showing the open / closed state of the oil relief passage and the timing of the on / off state of the solenoid valve.

  Details of a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention will be described below with reference to the drawings.

<Configuration of variable valve system>
The configuration of the variable valve operating apparatus 100 according to the embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the variable valve operating apparatus 100 according to the present embodiment includes a cam shaft 1, a cam 2 fixed to the cam shaft 1, and a side of the cam shaft 1 parallel to the cam shaft 1. The support shaft 3 arranged, a rocker arm 5 that opens and closes the intake valve 4 on the other end side in accordance with the swinging operation, a swinging arm 6, a hydraulic actuator 20, an oil reserve tank 30 as an accumulator, a solenoid A valve 40 and an engine control unit (ECU) 50 are provided.

(Intake valve)
The intake valve 4 is provided so as to be able to advance and retreat in the axial direction by a valve guide on the cylinder head side (not shown), and the upper end thereof is pulled up by the valve spring 11 supported by the valve retainer 17 (the direction in which the intake port and the combustion chamber are closed). It is energized. As shown in FIG. 5, the intake valve 4 is in contact with a valve seat (valve seat) 18 provided on the cylinder head side when the valve is closed.

(cam)
The camshaft 1 is rotatably supported by a bearing portion on the cylinder head side (not shown), and is rotated in conjunction with a crankshaft (not shown) by a chain or belt (not shown). The rotational speed of the camshaft 1 is set to be ½ of the rotational speed of the crankshaft, for example. In the present embodiment, the camshaft 1 is disposed so as to extend along the front-rear direction of the engine (not shown) (the direction indicated by the arrows in FIGS. 1 and 2).

  The cam 2 has a base circle portion 2A as a base and a nose portion 2B formed so as to bulge outward from the base circle portion 2A. The cam 2 is integrally provided by press-fitting and fitting the cam shaft 1 to the center of the base circle portion 2A. Therefore, the timing of the lift start of the intake valve 4 that operates in accordance with the operation of the crankshaft (not shown) is defined by the arrangement state of the cam 2 with respect to the camshaft 1.

(Rocker arm)
One end of the rocker arm 5 is pivotally supported on the support shaft 3. At the center of the rocker arm 5, a swing arm 6 is pivotally supported. An adjustment screw 9 that contacts the upper end of the intake valve 4 is fastened to the arm tip 5A on the other end side of the rocker arm 5 with a lock nut 10 so as to protrude downward. The valve clearance of the intake valve 4 can be adjusted as appropriate by adjusting the length by which the adjustment screw 9 projects downward from the arm tip 5A. On the one end side of the rocker arm 5, a detected portion 5B is provided at a position facing a gap sensor 7 as a sensor portion provided on a cylinder head (not shown).

(Swing arm)
The middle part of the swing arm 6 is pivotally supported by a fulcrum arm pin 8 as a rotation axis with respect to the rocker arm 5. The fulcrum arm pin 8 is fixed so as not to come off with a retaining clip 8A. The swing arm 6 includes an arm plate 12 bent at a pair of intermediate portions. A cylindrical first input roller 15 as a first contact portion is interposed between one end portions of the pair of arm plates 12, and the first input roller 15 is rotatably supported by a first roller pin 16. ing. Further, a cylindrical second input roller 13 as a second contact portion is interposed between the other ends of the pair of arm plates 12. The second input roller 13 is rotatably supported by a second roller pin 14. The first input roller 15 is set so that the cam surface of the cam 2 is always in contact. The second input roller 13 is set so as to always come into contact with a tappet 23 as a protruding and retracting portion of a hydraulic actuator 20 described later.

(Hydraulic actuator)
As shown in FIG. 3, the hydraulic actuator 20 used in the present embodiment is slidably fitted into a guide cylinder 21 having a first hydraulic chamber constituting pipe 21A coaxially therein and a first hydraulic chamber constituting pipe 21A. A piston 22 having a second hydraulic chamber constituting pipe 22A, a cylindrical container-like tappet 23 that is slidably fitted to the guide cylinder 21 in a state in which the piston 22 is housed, and between the guide cylinder 21 and the piston 22 A return spring 24 that is interposed and biases the piston 22 and the tappet 23 in a direction protruding from the guide cylinder 21; an oil passage case 25 that is provided at the top of the guide cylinder 21 and communicates with the first hydraulic chamber constituting pipe 21A; A check valve 26 provided in the case 25, an oil supply passage 27 communicating with the oil passage case 25 via the check valve 26, An oil pump 28 connected to the supply passage 27, and is configured with a.

  An internal space formed by the first hydraulic chamber constituting pipe 21 </ b> A and the second hydraulic chamber constituting pipe 22 </ b> A constitutes a hydraulic chamber 29. An inlet portion 25 </ b> A communicating with the oil supply passage 27 is formed in the upper portion of the oil passage case 25. In addition, an outlet 25B is formed at the side of the oil passage case 25. An oil relief passage 31 through which hydraulic oil can flow is communicated with the outlet portion 25B.

  The check valve 26 includes a check ball 26A, a mortar-shaped holding plate 26B formed with a circulation hole in the center for holding the check ball 26A, a check ball retainer 26C disposed on the downstream side of the check ball 26A, and a check ball. A check ball return spring 26D interposed between the retainer 26C and the guide cylinder 21 and biased to push up the check ball retainer 26C.

(Oil reserve tank and solenoid valve)
As shown in FIG. 4, the oil reserve tank 30 includes a cylinder 32 having an oil relief passage 31 communicating with a lower portion thereof, a piston 33 accommodated in the cylinder 32, and an upper inner wall of the cylinder 32 and the piston 33. A spring 34 that is interposed and biases the piston 22 toward the lower inner wall of the cylinder 32 is provided. In the upper part of the cylinder 32, an air vent hole 32A is formed. An oil relief hole 32C is formed at a predetermined height position of the side wall 32B of the cylinder 32.

The oil relief passage 31 is opened and closed by the plunger 41 of the solenoid valve 40 projecting and retracting in the oil relief passage 31. The solenoid valve 40 is controlled by the ECU 50 based on a control program stored in the ECU 50 as a control unit and an output signal of the gap sensor 7 that detects the distance to the detected portion 5B provided in the rocker arm 5. It has become.
(Operation of variable valve system)
Next, the operation of the variable valve apparatus 100 according to the present embodiment will be described.

(When maximum lift amount is selected)
FIG. 5 shows that the intake valve 4 is not operating when the maximum lift amount LMAX of the intake valve 4 is selected when the engine speed is equal to or higher than the predetermined speed (when no valve lift is occurring). It is a front view which shows the state. FIG. 6 shows a state where the lift amount is maximized by operating the intake valve 4 when the setting of the maximum lift amount of the intake valve 4 is selected.

  When the setting of the maximum lift amount is selected, the volume in the hydraulic chamber 29 is in the maximum state. Further, as shown in FIG. 5, the solenoid valve 40 is in a state in which the oil relief passage 31 is closed, and the hydraulic oil is in a state in which backflow is prevented by the check valve 26. Therefore, as shown in FIG. 3, in this state, the tappet 23 that operates together with the piston 22 of the hydraulic actuator 20 is held in a protruding state.

  As shown in FIG. 5, when the intake valve 4 is not in operation, the first input roller 15 in contact with the base circle 2A of the cam 2 has the cam 2 in the direction of arrow a (clockwise direction in the figure). Even if it rotates, the 1st input roller 15 is in the state which does not receive pressing force from the cam 2 side only by rolling.

  Next, as shown in FIG. 6, when the rotation of the cam 2 in the direction of arrow a proceeds, the nose portion 2B of the cam 2 comes into contact with the first input roller 15, and the first input roller 15 is pressed and pushed down. . When the first input roller 15 is pushed down, the swing arm 6 rotates in the clockwise direction in the drawing with the second input roller 13 as a fulcrum. Since the intermediate portion of the swing arm 6 is supported by the rocker arm 5 by the fulcrum arm pin 8, the rocker arm 5 rotates in the clockwise direction in the figure with the support shaft 3 as a fulcrum. Then, the adjusting screw 9 provided at the arm tip portion 5A of the rocker arm 5 presses the upper end of the intake valve 4, and the intake valve 4 is pushed down to the maximum lift amount LMAX against the repulsive force of the valve spring 11. .

  Further, from the state shown in FIG. 6, when the cam 2 further rotates in the direction of arrow a, the nose portion 2B passes through the first input roller 15 and the base circle portion 2A comes into contact with the first input roller 15 again, the rocking The arm 6 returns to the state (position) shown in FIG. With this operation, the arm tip 5A of the rocker arm 5 rises and the intake valve 4 rises due to the urging force of the valve spring 11 and is closed. (3) shown in FIG. 14 shows the relationship (valve lift characteristics) between the lift amount and the crank angle when the maximum lift is selected.

(When the minimum lift amount is selected)
Next, when the setting of the minimum lift amount (LMIN) of the intake valve 4 is selected when the engine load and the rotational speed are within a predetermined operation range, the intake valve 4 is not in operation (the valve lift is not generated). State) is the same as the state shown in FIG. FIG. 7 shows a valve lift state when the intake valve 4 is operated to reach the minimum lift amount when the setting of the minimum lift amount of the intake valve 4 is selected. FIG. 8 shows a state where the intake valve 4 is closed based on the operation of the hydraulic actuator 20, the oil reserve tank 30, and the solenoid valve 40 when the setting of the minimum lift amount of the intake valve 4 is selected.

  As shown in FIG. 5, when the intake valve 4 is in a non-operating state (the base circle portion 2A of the cam 2 is in contact with the first input roller 15), even if the cam 2 rotates in the direction of arrow a. The first input roller 15 is in a state where it only rolls and does not receive a pressing force from the cam 2 side. At this time, as shown in FIG. 10, the volume in the hydraulic chamber 29 is in the maximum state, the plunger 41 of the solenoid valve 40 is in a state in which the oil relief passage 31 is closed, and the hydraulic oil is supplied from the check valve 26. Backflow is blocked. Therefore, the tappet 23 that operates together with the piston 22 of the hydraulic actuator 20 is held in a protruding state.

  Next, as shown in FIG. 7, when the tappet 23 protrudes and the cam 2 rotates in the direction of arrow a, the base of the nose portion 2B of the cam 2 comes into contact with the first input roller 15 and the first The input roller 15 is gradually pressed. Therefore, the swing arm 6 rotates in the clockwise direction in the drawing with the second input roller 13 as a fulcrum. Since the intermediate portion of the swing arm 6 is supported by the rocker arm 5 by the fulcrum arm pin 8, the rocker arm 5 is illustrated with the support shaft 3 as a fulcrum in the state where the second input roller 13 is supported by the tappet 23 as described above. It rotates in the clockwise direction. Then, the adjustment screw 9 provided at the arm tip 5A presses the upper end of the intake valve 4 and pushes down the intake valve 4 against the repulsive force of the valve spring 11.

  When the predetermined position on the way to the top of the nose portion 2B of the cam 2 contacts the first input roller 15, the intake valve 4 has a preset minimum lift amount LMIN (see FIG. 7). With the minimum lift amount selected, the ECU 50 outputs a control signal for releasing the oil relief passage 31 to the solenoid valve 40 on the basis of the control program stored in the ECU 50 and the output value from the gap sensor 7. It is set to turn on the valve 40. Then, as shown in FIG. 8, the plunger 41 of the solenoid valve 40 is sunk to open the oil relief passage 31.

  FIG. 11 shows a state where the solenoid valve 40 is turned on and the oil relief passage 31 is opened when the intake valve 4 reaches the minimum lift amount. When the oil relief passage 31 is thus opened, the hydraulic oil in the hydraulic chamber 29 can move to the oil reserve tank 30 via the oil relief passage 31.

  At this time, the rocker arm 5 is pressed counterclockwise in the figure by the urging force of the valve spring 11 with the support shaft 3 as a fulcrum. Accordingly, the swing arm 6 is pressed in the clockwise direction in the drawing with the first input roller 15 contacting the cam surface of the cam 2 as a fulcrum. Therefore, the second input roller 13 of the swing arm 6 presses the tappet 23 so as to push it up. As the tappet 23 rises, the second hydraulic chamber constituting pipe 22A of the piston 22 in the tappet 23 rises in a state of being fitted to the first hydraulic chamber constituting pipe 21A on the guide cylinder 21 side, and the volume of the hydraulic chamber 29 is increased. Shrink.

  Here, since the backflow is prevented by the check valve 26 at the inlet portion 25A of the oil passage case 25, the hydraulic oil is sent from the outlet portion 25B of the oil passage case 25 to the oil relief passage 31. Then, when the hydraulic oil is sent out to the oil relief passage 31, the oil reserve tank 30 pushes up the piston 33 against the urging force of the spring 34, and the hydraulic oil is supplied to the space between the cylinder 32 below the piston 33. Save up. In the oil reserve tank 30, the air in the cylinder 32 is discharged from the air vent hole 32 </ b> A as the piston 33 rises, and the space flows into the cylinder 32 from the air vent hole 32 </ b> A when the piston 33 descends. It has become.

  In the oil reserve tank 30, when the piston 33 rises above the oil relief hole 32C, the hydraulic oil is discharged and collected from the oil relief hole 32C. By opening the oil relief passage 31 in this way, the tappet 23 of the hydraulic actuator 20 can be suddenly raised. Therefore, as indicated by the line (1) in FIG. 14, the intake valve 4 can be quickly closed, and the pump loss reduction effect can be enhanced.

  In order to prevent the intake valve 4 from rapidly rising and colliding with the valve seat 18 at a high speed in this way, control as indicated by an alternate long and short dash line ellipse is performed in the timing chart of FIG. ing. That is, as shown by arrow b in FIG. 9, when the second input roller 13 of the swing arm 6 rises as the tappet 23 rises, the rocker arm 5 rotates counterclockwise in the figure with the support shaft 3 as a fulcrum. To do. When the detected portion 5 </ b> B of the rocker arm 5 approaches the gap sensor 7 to a predetermined distance, the gap sensor 7 outputs a detection signal to the ECU 50. FIG. 14 shows the valve lift position calculated as the output value of the gap sensor 7 based on the distance between the gap sensor 7 and the detected portion 5B.

  At this time, the ECU 50 outputs a control signal for turning off the solenoid valve 40 based on the output signal from the gap sensor 7. As a result, as shown in FIG. 12, the plunger 41 of the solenoid valve 40 protrudes and closes the oil relief passage 31. When the oil relief passage 31 is closed in this way, the hydraulic oil sealed in the oil pressure passage 29 and the oil relief passage 31 communicating with the hydraulic chamber 29 acts to suppress the piston 22 from rising. That is, the quick rise of the second input roller 13 is alleviated. Along with this, the rocking speed of the rocker arm 5 in the counterclockwise direction in FIG. 9 is reduced, and as a result, the rapid rise of the intake valve 4 is reduced. Therefore, the intake valve 4 can be prevented from suddenly colliding with the valve seat 18. In the present embodiment, it is possible to correct the set value of the timing for turning off the solenoid valve 40 in accordance with conditions such as the temperature of hydraulic oil, the hydraulic pressure, and the engine speed.

  As indicated by the one-dot chain line ellipse in FIG. 14 (1), when the intake valve 4 is seated on the valve seat 18, a control signal is output from the ECU 50, the solenoid valve 40 is turned on, and the plunger 41 is sunk. Thus, the oil relief passage 31 is opened. As shown in FIG. 9 from the state of FIG. 8, when the cam 2 rotates in the direction of arrow a and the nose portion 2B passes through the first input roller 15, the first input roller 15 is pushed down. Accordingly, the swing arm 6 is pressed clockwise in the figure with the fulcrum arm pin 8 as a fulcrum.

  At this time, the rocker arm 5 is pressed by the swing arm 6 so as to rotate in the clockwise direction in the drawing with the fulcrum arm pin 8 as a fulcrum. However, since the load of the valve spring 11 is set to be larger than the combined load of the return spring 24 and the spring 34, as shown in FIG. 9, the rocker arm 5 does not rotate in the clockwise direction in the figure. The swing arm 6 rotates in the clockwise direction in the figure with the fulcrum arm pin 8 as a fulcrum, and the second input roller 13 pushes up the tappet 23. Therefore, even if the nose portion 2B of the cam 2 passes through the first input roller 15, the intake valve 4 is not lifted.

  As shown in FIG. 14, after the lift operation of the minimum lift amount of (1) is completed and the cam 2 is rotated to the angle at which the lift operation of (3) ends when the cam 2 is at the maximum lift amount, 13, the return spring 24 of the hydraulic actuator 20 pushes down the tappet 23. At this time, the hydraulic chamber 29 is expanded, and the hydraulic oil in the oil reserve tank 30 flows into the hydraulic chamber through the oil relief passage 31. Thereafter, the oil relief passage 31 is closed and hydraulic oil is supplied from the oil pump 28 through the check valve 26 into the hydraulic chamber 29 so that the tappet 23 protrudes to the maximum. By projecting the tappet 23 before the next valve lift step, the intake valve 4 can be operated again with the minimum lift amount or the maximum lift amount of the intake valve 4.

  (2) in FIG. 14 shows a modified example of the valve lift using the variable valve operating apparatus 100 according to the present embodiment, and the valve lift characteristic when the valve after the lift of the maximum lift amount is quickly closed. Is shown. Moreover, (4) in FIG. 14 is a comparative example, and shows the valve lift characteristics of a variable valve operating apparatus using a lost motion mechanism.

  In the variable valve operating apparatus 100 according to the above-described embodiment, when the valve lift amount and the valve operating angle of the intake valve 4 are reduced, the intake valve is at the same time as when the valve lift amount and the valve operating angle are maximized. 4 can be opened and only the timing when the intake valve 4 is closed can be advanced. Therefore, when reducing the valve lift amount and the valve operating angle of the intake valve 4, the intake valve 4 can be closed earlier at the same intake air amount than the conventional variable valve operating system using the lost motion mechanism. Engine pump loss can be reduced.

  In the variable valve operating apparatus 100 according to the present embodiment, when the valve lift amount and the valve operating angle of the intake valve 4 are made smaller, the valve is operated at the same intake air amount than the variable valve operating apparatus using the conventional lost motion mechanism. Since the valve lift can be increased while reducing the operating angle, the pump loss of the internal combustion engine can be reduced.

  In the variable valve apparatus 100 according to the present embodiment, when the intake valve 4 is lifted, a hydraulic drive system using a hydraulic passage is not used, so that a pressure loss due to the hydraulic drive does not occur, and the variable valve apparatus 100 as a whole. Drive loss can be reduced.

  In the variable valve operating apparatus 100 according to the present embodiment, the hydraulic chamber 29 is expanded with hydraulic oil supplied from the oil pump 28 before the intake valve 4 is lifted, and the hydraulic chamber is used when the intake valve 4 is lifted. When the check valve 26 is closed by the pressure increase of 29 and the intake valve 4 is fully lifted, it can be lifted with the same valve lift characteristic.

  In the variable valve operating apparatus 100 according to the present embodiment, the intake valve 4 can be immediately closed by releasing (opening) the oil relief passage 31 at an arbitrary timing by the solenoid valve 40.

  In the variable valve apparatus 100 according to the present embodiment, the hydraulic chamber 29 is expanded by the return spring 24 after the nose portion 2B passes through the position where the first input roller 15 is pushed down to the maximum by the rotation of the cam 2, and the piston 22 Thus, the second input roller 13 can be pushed to swing the swing arm 6 so that the first input roller 15 can be constantly pressed against the cam surface of the cam 2. Therefore, according to the variable valve operating apparatus 100 according to the present embodiment, it is possible to prevent the swing arm 6 from rattling or unstable operation. In addition, when the volume of the hydraulic chamber 29 is expanded by the return spring 24, the hydraulic oil stored in the oil reserve tank 30 can be supplied to the hydraulic chamber 29, and the hydraulic oil can be used efficiently. The burden can be reduced.

  Since the variable valve operating apparatus 100 according to the present embodiment is configured to accumulate a predetermined amount of hydraulic oil in the hydraulic chamber 29, the hydraulic oil functions as a buffer material and the intake valve 4 is seated on the valve seat 18. Can reduce the impact.

[Other embodiments]
Although the embodiment has been described above, it should not be understood that the description and the drawings constituting a part of the disclosure of the embodiment limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the above embodiment, when the minimum lift amount is selected, the timing for opening the oil relief passage 31 is determined in advance based on the distance between the gap sensor 7 and the detected portion 5B. The oil relief passage 31 may be opened by controlling the solenoid valve 40 based on the arrangement state of the cam 2 (the angle state of the cam operating angle).

  Moreover, in the said embodiment, although the intrusion part which contacts the 2nd input roller 13 was the tappet 23 of the hydraulic actuator 20, it is good also as a structure which makes the piston 22 contact directly.

  Further, in the above embodiment, when the minimum lift amount is selected, the oil relief passage 31 is controlled to be released again after the closing operation of the intake valve 4 is completed. However, the oil relief passage 31 is again released immediately before the closing operation is completed. May be released.

DESCRIPTION OF SYMBOLS 100 Variable valve apparatus 1 Cam shaft 2 Cam 2A Base circle part 2B Nose part 3 Support shaft 4 Intake valve 5 Rocker arm 5A Arm tip part 5B Detected part 6 Swing arm 7 Gap sensor (sensor part)
8 fulcrum arm pin (rotary shaft)
13 Second input roller (second contact portion)
15 1st input roller (1st contact part)
18 Valve seat 20 Hydraulic actuator 21 Guide cylinder 21A First hydraulic chamber constituting pipe 22 Piston 22A Second hydraulic chamber constituting pipe 23 Tappet (protruding part)
24 Return spring 25 Oil passage case 26 Check valve 27 Oil supply passage 28 Oil pump 29 Hydraulic chamber 30 Oil reserve tank (accumulator)
31 Oil relief passage 32 Cylinder 32C Oil relief hole 33 Piston 34 Spring 40 Solenoid valve 41 Plunger 50 ECU

Claims (2)

A rocker arm that is pivotally supported by the support shaft and opens / closes the intake valve in accordance with the rocking operation, and an intermediate portion is pivotally supported by the rocker arm with a rotary shaft so that the rotary shaft is sandwiched between them. A swing arm having a first contact portion and a second contact portion;
A cam fixed to a camshaft disposed in the vicinity of the first contact portion and having a cam that allows the intake valve to lift by contacting the first contact portion and a projecting portion that contacts the second contact portion. And a hydraulic chamber that changes its volume with hydraulic oil and drives the protrusions and recesses according to the volume changes,
A hydraulic actuator that reduces the volume of the hydraulic chamber and retracts the protruding and retracting portion to close the intake valve at an arbitrary timing while the intake valve is lifted by the cam crest of the cam. A variable valve operating apparatus for an internal combustion engine. A cylinder head that supports the camshaft;
A gap sensor that is provided in the cylinder head and detects a distance from the detected portion at a position facing the detected portion provided at an end of the rocker arm on the support shaft side;
An oil relief passage communicating with the hydraulic chamber;
The variable valve operating apparatus for an internal combustion engine according to claim 1, further comprising a solenoid valve that is controlled to open and close the oil relief passage based on an output signal of the gap sensor.

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