JPH04287809A - Valve system of internal combustion engine - Google Patents

Abstract

PURPOSE:To control continuously rotating phase between a valve system cam shaft and crank shaft with simple construction, in the valve system of an internal combustion engine which is provided with an operating mechanism having a piston capable of controlling the rotating phase between the valve system cam shaft and the crank shaft according to its moving position in an axial direction and facing its one end surface in the axial direction to an oil pressure chamber, while being energized by a spring to the side where the volume of the oil pressure chamber is reduced and provided with an oil pressure control valve for controlling oil pressure in the oil pressure chamber. CONSTITUTION:An oil pressure control valve 14 is formed in such constitution that the force of a spring 49 directed toward an oiling position is acted on one end of a spool 41 fitted slidably in a housing 40, and the other end side of the spool 41 is so arranged that a back pressure chamber 51 communicating to an output port 44 can exhibit its oil pressure force toward an opening position, and an actuator 42 for exhibiting thrust according to an input electric amount regardless of an operating position is interlocked and connected to either side in the axial direction, of the spool 41.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention provides a valve drive camshaft and a crankshaft for driving an engine valve supported in an openable and closable manner in an engine body. an actuating mechanism capable of controlling the rotational phase of a crankshaft, having one axial end face facing a hydraulic chamber, and having a piston biased by a spring toward a side that reduces the volume of the hydraulic chamber;
The present invention relates to a valve operating device for an internal combustion engine in which a phase control means including a hydraulic control valve that controls the hydraulic pressure of the hydraulic chamber is interposed.

0002

2. Description of the Related Art Conventionally, such a valve train is already known from, for example, Japanese Patent Application Laid-Open No. 59-120707.

0003

[Problem to be Solved by the Invention] In the phase control means of such a valve train, the hydraulic pressure in the hydraulic chamber is controlled by a two-port, two-position electromagnetic control valve, thereby controlling the opening/closing timing of the engine valve. Basically, there are only two states that can be obtained: applying hydraulic pressure to the hydraulic chamber or releasing hydraulic pressure.
Therefore, only two types of rotational phases can be obtained between the valve train camshaft and the crankshaft. However, depending on the operating state of the engine, changes in the rotational phase have a large effect on engine performance, especially in the low to medium speed range, and engine performance can be significantly improved by varying the rotational phase in multiple stages or continuously. becomes possible.

[0004] The above-mentioned Japanese Patent Application Laid-Open No. 59-120707 discloses that it is possible to continuously change the rotational phase by finely changing the position of a 2-port 2-position electromagnetic control valve by controlling the duty. However, considering that the amount of oil leaking from each gap in the operating mechanism changes depending on the temperature of the hydraulic oil, and that the amount of leakage changes depending on the machining accuracy, the amount of oil leaking between the valve train camshaft and the crankshaft It is necessary to detect the rotational phase and perform feedback control of the electromagnetic control valve, which requires a means for detecting the rotational phase and a feedback control system, making the configuration complicated.

The present invention has been made in view of the above circumstances, and provides a valve train for an internal combustion engine that allows continuous control of the rotational phase between the valve train camshaft and the actual opening of the crank with a simple configuration. The purpose is to provide equipment.

[0006]

[Means for Solving the Problems] In order to achieve the above object, according to a first feature of the present invention, a hydraulic control valve has an input port leading to a hydraulic pressure source, an output port leading to a hydraulic chamber, and an oil tank. axially between a housing with a release port communicating therewith, a refueling position that communicates the input port with the output port, a blocking position that isolates the input port, the output port, and the release port from each other, and a release position that communicates the output port with the release port. a spool that is movable and slidably fitted into the housing; a spring that is interposed between the housing and one end of the spool to bias the spool toward the refueling position; an actuator that exerts an actuating force that biases the spool in one direction, and a back pressure chamber that communicates with the output port is formed so that the other end of the spool faces toward the release position, The actuator is configured to exert a thrust corresponding to an input amount of electricity regardless of the actuation position.

According to a second feature of the invention, the actuator is a linear solenoid.

According to a third feature of the invention, a gap is provided at a constant distance between the spool in the cut-off position and the actuator in the inactive state.

According to a fourth feature of the invention, the output port communicates with the back pressure chamber via the orifice.

0010

Embodiments Hereinafter, embodiments of the present invention will be explained with reference to the drawings.

1 to 8 show one embodiment of the present invention, in which FIG. 1 is an overall longitudinal sectional side view, FIG. 2 is an enlarged longitudinal sectional view of the phase control means, and FIG. The corresponding axial thrust characteristic diagram, Figure 4 is the axial thrust characteristic diagram corresponding to the stroke of the linear solenoid, Figure 5 is a simplified diagram showing the force acting on the spool of the hydraulic control valve, and Figure 6 is the application of the linear solenoid. FIG. 7 is an enlarged sectional view of the contact portion between the linear solenoid and the spool, and FIG. 8 is an enlarged longitudinal sectional view of the lift amount control means.

First, in FIG. 1, a cylinder head 1 of an engine body E is provided with an intake valve port 3 that opens at the top of a combustion chamber 2 formed between the cylinder block and a cylinder block (not shown) and communicates with an intake port 4. At the same time, an intake valve 5 serving as an engine valve capable of opening and closing the intake valve port 3 is arranged so as to be vertically movable. A flange portion 6 is provided at the upper end of the intake valve 5,
A valve spring 7 is compressed between the flange 6 and the cylinder head 1, and the spring force of the valve spring 7 urges the intake valve 5 upward, that is, in the valve closing direction.

On the other hand, a valve drive camshaft 9 is rotatably supported in a holder 8 at a position above the cylinder head 1.
This valve drive camshaft 9 is interlocked and connected to a crankshaft (not shown) via a phase control means 10. Also, the valve train camshaft 9
Lift amount control means 12 is interposed between the intake valve 5 and the valve operating cam 11, which is provided integrally with the intake valve 5.

Referring also to FIG. 2, the phase control means 10
includes an actuation mechanism 13 operable to change the rotational phase of a crankshaft and valve drive camshaft 9 (not shown), and a hydraulic control valve 14 capable of controlling the hydraulic pressure applied to the actuation mechanism 13.

The operating mechanism 13 includes a pulley 16 around which a timing belt 15 for transmitting rotational power from the crankshaft is wound, a rotating shaft 17 coaxially connected to the valve drive camshaft 9 by a bolt 23, and a pulley 16. a casing 18 that is basically a cylinder with a bottom and is integrally provided with the valve drive camshaft 9 and coaxially surrounds the end of the valve drive camshaft 9 and the rotating shaft 15; an end plate 19 that closes the open end of the casing 18; A piston 21 is slidably fitted to the rotating shaft 17 and the casing 18 while defining a hydraulic chamber 20 between the end plate 19 and a return mechanism that urges the piston 21 toward the hydraulic chamber 20. A spring 22 is provided.

The casing 18 is basically formed into a bottomed cylindrical shape with a cylindrical portion 18a coaxially surrounding the valve drive camshaft 9 at the closed end, and the outer surface of the cylindrical portion 18a and the space between the holder 8 An annular sealing member 24 is interposed therein. Further, the pulley 16 is provided on the outer periphery of the housing 18.

A housing 18 is provided on the outer surface of the piston 21.
An O-ring 25 that slides on the inner surface of the rotating shaft 17 is fitted, and an O-ring 26 that slides on the outer surface of the rotating shaft 17 is fitted on the inner surface. The rotating shaft 17 also has a flange 17a that extends outward in the radial direction while facing the closed end of the casing 18, and a cylindrical portion 1 that extends from the outer end of the flange 17a toward the piston 21.
7b, and the return spring 22 is connected to the flange 17.
a and the piston 21. Moreover, the piston 21 has a coaxially protruding cylindrical portion 21a disposed between the cylindrical portion 17a and the housing 18, and the outer surface of the cylindrical portion 21a and the inner surface of the casing 18 are connected via a helical spline 27. and the cylindrical part 21
The inner surface of a and the outer surface of the cylindrical portion 17b are connected via a helical spline 28. Therefore piston 2
According to the axial movement of 1, the pulley 16 is attached to the casing 18.
The rotational phase between the crankshaft and the rotating shaft 17, that is, the valve drive camshaft 9, which are connected to each other via the timing belt 15, changes.

Referring again to FIG. 1, the cylinder head 1 is provided with an oil bath 32 as an oil tank.
An oil supply path 31 including a relief valve 29 and a filter 30 is connected to a discharge port of an oil pump P as a hydraulic source for pumping oil from the oil bath 32 in this order from the upstream side. Furthermore, from the oil supply path 31, there is a branch oil path 33 dedicated to the phase control means 10, a branch oil path 34 for the lift amount control means 12, and a journal portion of each lubricating part in the cylinder head 1, that is, the valve drive camshaft 9. The lubricating branch oil passage 35 is branched to supply lubricating oil to the sliding contact portions of the valve drive cam 11, etc., and an orifice 36 is interposed in the lubricating branch oil passage 35.

The branch oil passage 33 is provided in the cylinder head 1 and the holder 8, and is connected to the phase control means 1.
An oil passage 37 whose one end communicates with the oil pressure chamber 20 at 0 is
The oil passage 37 is bored through the rotating shaft 17 and the valve drive camshaft 9.
is constantly communicated with the downstream portion 33b of the branch oil passage 33. Moreover, an accumulator 53 is interposed in the upstream portion of the branch oil passage 33.

The hydraulic control valve 14 is interposed between the upstream portion 33a and the downstream portion 33b of the branch oil passage 33. This hydraulic control valve 14 includes a housing 40 attached to the side surface of the cylinder head 1, a spool 41 slidably fitted into the housing 40, and a spring 49 urging the spool 41 to one side in the axial direction. A linear solenoid 42 is provided as an actuator attached to the housing 40 to press the spool 41 in the axial direction.

The housing 40 includes an input port 43 connected to the upstream side portion 33a of the branched oil passage 33, an output port 44 connected to the downstream side 33b of the branched oil passage 33, and a release port 45 connected to the oil bath 32. and is provided. Further, the housing 40 is provided with a large diameter sliding hole 46 whose one end is closed with a cap 48 and a small diameter sliding hole 47 coaxially connected to the other end of the large diameter sliding hole 46. It is slidably fitted into the large diameter sliding hole 46 and the small diameter sliding hole 47. A spring 49 is compressed between the cap 48 and one end of the spool 41, and a linear solenoid 42 is coaxially interlocked and connected to the other end of the spool 41. That is, the linear solenoid 42 is attached to the outer surface of the housing 40, and the drive rod 52 of the linear solenoid 42 coaxially abuts the other end of the spool 41. Further, the housing 40 includes an orifice 50.
A back pressure chamber 51 connected to the output port 44 via the spool 41 is formed so as to face the other end side of the spool 41.

The spool 41 has a refueling position where the input port 43 and the output port 44 are connected to each other, a blocking position where the output port 44 is isolated from the input port 43 and the release port 45, and a release position where the output port 44 is connected to the release port 45. The position of the linear solenoid 42 applied to the other end in the axial direction
The switching is performed in response to changes in the axial position due to the magnitude relationship between the axial thrust of the back pressure chamber 51, the hydraulic pressure of the back pressure chamber 51, and the spring force of the spring 49 acting on one end in the axial direction.

As shown in FIG. 3, the linear solenoid 42 generates an axial thrust FA that varies proportionally in accordance with its input electrical quantity, such as the applied current I or the input voltage when the resistance is constant. be. Moreover, when the input electrical quantity, for example, the applied current I, is constant, the operating stroke changes from "0" to a certain value "L0", as shown in FIG.
'', the linear solenoid 42 generates a constant thrust according to the applied current I0 to 1/4I0 regardless of the operating stroke.

Next, the operation of the hydraulic control valve 14 will be explained. When the linear solenoid 42 is demagnetized, the spool 41 is in a refueling position where the input port 43 is communicated with the output port 44. When hydraulic pressure acts on the input port 43 from the upstream portion 33a of the branch oil passage 33 in this state,
The oil pressure acts on the downstream portion 33b of the branch oil passage 33 via the output port 44 and acts on the back pressure chamber 51 via the orifice 50, and the oil pressure acting on the back pressure chamber 51 causes the spring force of the spring 49 to be Hydraulic pressure is applied to the spool 41 to push the output port 44 to the blocking position where it is isolated from the input port 43 and the release port 45. When a current is applied to the linear solenoid 42, the linear solenoid 42 operates the drive rod 52 in the axial direction with an axial thrust corresponding to the applied current, thereby causing the spool 41 to communicate the output port 44 with the release port 45. driven into position. By controlling the current applied to the linear solenoid 42 in this way, the spool 41 can be placed in the refueling position where the input port 43 and the output port 44 are communicated, the blocking position where the output port 44 is isolated from the input port 43 and the release port 45, In addition, the release position where the output port 44 is communicated with the release port 45 is switched, whereby the hydraulic pressure in the upstream portion 33a of the branch oil passage 33 is controlled and acts on the downstream portion 33b, that is, the hydraulic chamber 20 of the actuating mechanism 13. Become.

The load direction of such a hydraulic control valve 14 is shown in FIG. If the pressure receiving area facing the chamber 51 is S, and the axial thrust of the linear solenoid 42 is FA, then the spool 41
a force that presses the button toward the release position (right position in Figure 5);
The force that pushes the spool 41 toward the refueling position (the left position in Figure 5) is balanced when the spool 41 is in the cutoff position (the intermediate position in Figure 5), and in that balanced state, Equation 1 is satisfied. can get.

[0026]

[Math 1]

Furthermore, the axial thrust F of the linear solenoid 42
A is FA as shown in Figure 3, assuming that the proportionality constant is α.
=αI, therefore, Formula 2 can be obtained from Formula 1 above.

[0028]

[Math 2]

Here, the spring load FS when the spool 41 is in the cutoff position is a constant value that is determined when the positions of the ports 43, 44, and 45 in the housing 40 are set, and as is clear from the above equation 2. In, back pressure chamber 5
1 hydraulic pressure PC, that is, hydraulic chamber 2 in the operating mechanism 13
The oil pressure of 0 and the applied current I of the linear solenoid 42 have a proportional relationship as shown in FIG.

By the way, in the hydraulic control valve 14,
Assuming that the back pressure chamber 51, that is, the hydraulic pressure PC of the hydraulic chamber 20, is reduced to a value lower than the value determined by the applied current I of the linear solenoid 42 due to a leak or the like, the spool 41 moves to the refueling position, and the input port 43 and output port 44
The hydraulic pressure in the back pressure chamber 51 is increased by the communication between
The oil pressure of 0 is controlled to a value corresponding to the applied current I. Further, assuming that the hydraulic pressure PC in the back pressure chamber 51 increases due to supercharging to a value higher than the value determined by the applied current I of the linear solenoid 42, the spool 41 moves to the release position and As a result, the hydraulic pressure in the back pressure chamber 51 is reduced, whereby the spool 41 moves to the cutoff position, and the hydraulic pressure in the hydraulic chamber 20 is controlled to a value corresponding to the applied current I. In this way, the hydraulic pressure PC in the hydraulic chamber 20, that is, the back pressure chamber 51 is controlled by the linear solenoid 42.
The hydraulic control valve 14 has a structure that allows it to self-reset even if it deviates from the value corresponding to the applied current I.

Further, as shown in FIG. 7, the spool 41 is in the cutoff position and the linear solenoid 42 is in the inactive state.
A gap 54 is set at a constant interval between the linear solenoid 42 and the linear solenoid 42, as shown in FIG. This corresponds to having an unstable region, and since the linear solenoid 42 has an idle stroke, the linear solenoid 42 is connected to the spool 41 only in the stable region.
It is possible to apply an axial thrust from.

Furthermore, in the actuation mechanism 13, the piston 2
1 is connected to the valve drive camshaft 9 via a helical spline 28, and the vibration component of the drive load of the valve drive cam 11 causes the piston 21 to vibrate in the axial direction, causing the hydraulic pressure in the hydraulic chamber 20, that is, the back pressure chamber. 51 may fluctuate. However, since the back pressure chamber 51 communicates with the hydraulic pressure chamber 20 via the orifice 50, fluctuations in the hydraulic pressure in the back pressure chamber 51 can be avoided as much as possible, and adverse effects on the hydraulic control valve 14 can be avoided.

Next, the structure of the lift amount control means 12 will be explained with reference to FIG. , transmission oil chamber 5 in the transmission mechanism 55
6, an accumulator 58, a feed valve 59, and a check valve 60.

The transmission mechanism 55 includes a cylinder body 62 fixed to a support block 61 fixed to the upper part of the cylinder head 1, and a cylinder body 62 fixed to the support block 61 while slidingly contacting the valve drive cam 11.
a lifter 63 that is slidably fitted to the upper part of the cylinder body 62; a cam driven piston 64 that is slidably fitted to the upper part of the cylinder body 62 with its upper end in contact with the lifter 63; and a valve driving piston 65 slidably fitted to the lower part of the cylinder body 62 while abutting on both pistons 64.
, 65, a transmission oil chamber 56 is formed between them.

The cylinder body 62 has a partition wall 6 in its middle part.
The cam driven piston 64 is slidably fitted into the upper part of the cylinder body 62 while defining an upper oil chamber 56a between it and the partition wall 66.
The valve driving piston 65 has a lower oil chamber 56 between it and the partition wall 66.
The cylinder body 62 is slidably fitted to the lower part of the cylinder body 62 while defining a portion b. Thus, the upper oil chamber 56a and the lower oil chamber 56b
is connected via a check valve 67 disposed on the lower oil chamber 56b side of the partition wall 66 to allow oil to flow only from the upper oil chamber 56a to the lower oil chamber 56b, They cooperate to form a transmission oil chamber 56. Also, the upper oil chamber 5
A spring 68 that biases the cam driven piston 64 toward the lifter 63 is housed in the spring 6a.

Moreover, an annular recess 69 is provided on the inner surface of the cylinder body 62 below the partition wall 66.
Oil passage 7 communicating this annular recess 69 and upper oil chamber 56a
0 is drilled into the cylinder body 62. Further, the upper part of the valve drive piston 65 is formed into a thin cylindrical shape, and an orifice 71 that constantly communicates the lower oil chamber 56b with the annular recess 69 is bored in this thin cylindrical part.

The transmission mechanism 55 is in the state shown in FIG. 3 in the fully closed state of the intake valve 5 when the hydraulic pressure release valve 57 is closed, and from this state, the cam is driven in accordance with the rotation of the valve drive cam 11. When the piston 64 is pushed down, the oil pressure in the upper oil chamber 56a is guided to the lower oil chamber 56b via the oil passage 70 and the orifice 71, but the oil pressure in the upper oil chamber 56a is lower than the oil pressure in the lower oil chamber 56b. Since the check valve 67 opens when is larger than a predetermined value, hydraulic pressure acts from the upper oil chamber 56a to the lower oil chamber 56b via the check valve 67,
Valve drive piston 65 is pushed down.

During the downward sliding of the valve driving piston 65, the oil passage 70 directly communicates with the lower oil chamber 56b through the annular recess 69, and the amount of oil flowing into the lower oil chamber 56b increases, causing the valve to close. The drive piston 65 is further pushed downward, and the intake valve 5 opens against the spring force of the valve spring 7.

After the intake valve 5 is fully closed, when the pressing force by the valve operating cam 11 is released, the intake valve 5 is driven upward by the spring force of the valve spring 7, that is, in the valve closing direction. This valve-closing operation of the intake valve 5 also pushes the valve drive piston 65 upward, and the oil in the lower oil chamber 56b is returned to the upper oil chamber 56a through the oil passage 70.

During the closing operation of the intake valve 5, the direct communication between the annular recess 69 and the lower oil chamber 56b is released, and the orifice 71 is interposed between the lower oil chamber 56b and the annular recess 69. Then, the amount of oil returning from the lower oil chamber 56b to the upper oil chamber 56a is limited. Therefore, the upward movement speed of the intake valve 5, that is, the valve closing speed, is slowed down in the middle of the valve closing operation, and the intake valve 5 is seated gently, so that the impact upon seating is alleviated.

When the hydraulic pressure in the transmission oil chamber 56 , that is, the oil passage 70 in the transmission mechanism 55 is released during the opening operation of the intake valve 5 , the transmission oil chamber 56 overcomes the spring force of the valve spring 7 and closes the intake valve 5 . The transmission function to keep the valve open is lost, and even though the valve operating cam 11 continues to push the lifter 63 downward, the intake valve 5 is prevented by the elastic force of the valve spring 7 from the time of hydraulic pressure release. The valve closing operation starts, and the transmission oil chamber 56 contracts.

The hydraulic pressure release valve 57 is connected to the intake valve 5 as described above.
It controls the release of hydraulic pressure from the transmission oil chamber 56 during the valve opening operation, and connects a passage 74 bored in the support block 61 and communicating with the oil passage 70, and the pressure accumulation chamber 9 of the accumulator 58.
A passage 7 bored in the support block 61 while communicating with the passage 7
5.

[0043] This hydraulic release valve 57 includes a control valve section 76,
and an electromagnetic drive section 77 that drives the control valve section 76. The control valve section 76 has a main valve body 79 slidably fitted into the valve housing 78 and capable of switching between communication and isolation between the passages 74 and 75, and opening/closing movement of the main valve body 79. The electromagnetic drive section 77 is connected to the control valve section 76 to open and close the pilot valve 80 . That is, the valve housing 78 of the control valve section 76 is coupled to the casing 81 of the electromagnetic drive section 77 .

The main valve body 79 is formed into a cylindrical shape with a bottom. The main valve body 79 opens the passage 74, ie, the hydraulic pressure of the transmission oil chamber 56, while acting on its front surface in the valve opening direction.
The housing 78 is biased by a spring in a direction that blocks the gap between the housing 75 and the housing 78.
A pilot chamber 82 is formed at the back of the main valve body 79 . Therefore, the oil pressure in the passage 74 acts on the main valve body 79 in the valve opening direction, and the oil pressure and spring force in the pilot chamber 82 act on the main valve body 79 in the valve closing direction. Further, the main valve body 79 is provided with an orifice 83 that allows the passage 74 to communicate with the pilot chamber 82 .

The pilot valve 80 is connected to the pilot chamber 8.
2 and the outside, and the electromagnetic drive unit 7
7. That is, the electromagnetic drive unit 77 includes a solenoid 84 and a movable core 85 driven by the solenoid 84, and the pilot valve 80 opens in response to the movement of the movable core 85 when the solenoid 84 is energized.

In such a hydraulic release valve 57, when the solenoid 84 of the electromagnetic drive unit 77 is energized, the pilot valve 80 opens and the hydraulic pressure in the pilot chamber 82 is released. Therefore, the balance of the hydraulic pressure acting on both sides of the main valve body 79 is lost, and the valve opening force due to the hydraulic pressure of the passage 74 acting on the front surface overcomes the hydraulic pressure of the pilot chamber 82 and the valve closing force due to the spring, and the valve opens. Operate.

When the pilot valve 80 is closed by demagnetizing the solenoid 84, the hydraulic pressure in the passage 74 acts on the pilot chamber 82 through the orifice 83, and the main valve body 79 is operated to close.

[0048] The accumulator 58 is connected to the support block 61.
An accumulator piston 89 is slidably fitted into a bottomed sliding hole 88 provided in the bottom, and a pressure accumulation chamber 92 is formed between the closed end of the sliding hole 88 and the accumulator piston 89.
An accumulator spring 91 is compressed between the cap 90 that closes the open end of the sliding hole 88 and the accumulator piston 89, and that biases the accumulator piston 89 in a direction to contract the volume of the pressure accumulation chamber 92. Ru.

The feed valve 59 is connected to the accumulator 5.
It is disposed in the support block 61 between the pressure accumulation chamber 92 of No. 8 and the passage 74, bypassing the hydraulic pressure release valve 57, and only allows oil to flow from the pressure accumulation chamber 92 to the passage 74. It is permissible. In addition, the check valve 60 is connected to the pressure accumulation chamber 9.
2 and the feed valve 59, and is disposed on the support block 61 to allow oil to flow toward the pressure accumulation chamber 92 and the feed valve 59 side.

A lift sensor S is also disposed on the support block 1 to detect the upper end of the intake valve 5 when the intake valve 5 is completely closed.

By the way, the transmission mechanism 55, hydraulic pressure release valve 57, accumulator 58, feed valve 59, and check valve 60 are respectively arranged corresponding to the intake valve 5 of each cylinder in a multi-cylinder internal combustion engine. The check valve 60 in each cylinder is connected to a common oil passage 93 bored in the cylinder head 1 for each cylinder, and this common oil passage 93 is connected to a branch oil passage 34 provided with a pressure regulating valve 94. Ru.

The pressure regulating valve 94 includes a housing 95 attached to the side surface of the cylinder head 1, and a spool 96 slidably fitted into the housing 95. The housing 95 has an input port 97 connected to the upstream portion 34a of the branch oil passage 34, an output port 98 connected to the downstream portion 34b of the branch oil passage 34, and an output port 98 connected to the oil bath 32 and bored in the cylinder head 1. A release port 99 connected to the release oil passage 100 is provided. The housing 95 also has a large diameter sliding hole 101 with one end closed, and a large diameter sliding hole 10
A small-diameter sliding hole 102 coaxially connected is bored at the other end of the spool 96, and the spool 96 is slidably fitted into the large-diameter sliding hole 101 and the small-diameter sliding hole 102. A spring 10 is disposed between one end of the large diameter sliding hole 101 and one end of the spool 96.
3 will be reduced. Further, the housing 95 includes a back pressure chamber 105 connected to the output port 98 via an orifice 104.
is formed with the other end of the spool 96 facing.

The spool 96 has a position that communicates the input port 97 and the output port 98, a position that isolates the output port 98 from the input port 97 and the release port 99, and a position that communicates the output port 98 with the release port 99.
The hydraulic pressure of the back pressure chamber 105 and the spring 10 acting on one end in the axial direction
The switching is performed according to the change in the axial position due to the magnitude relationship with the spring force No. 3.

In the pressure regulating valve 94, the back pressure chamber 105
When the oil pressure is low, the spool 96 is in a position where the input port 97 and the output port 98 are communicated with each other as shown in FIG.
When hydraulic pressure acts on the input port 97 from the input port 97, the hydraulic pressure acts on the downstream portion 34b of the branch oil passage 34 through the output port 98, and also flows through the orifice 104 into the back pressure chamber 10.
5 and the hydraulic pressure acting on the back pressure chamber 105 causes the output port 98 to move against the spring force of the spring 103 to the input port 9.
Hydraulic pressure acts on the spool 96 to push it into a position spaced from the spool 96 and the release port 99 . Therefore, output port 98
As the oil pressure increases further, the spool 96 is driven into a position that communicates the output port 98 with the release port 99. Therefore, the spool 96 is moved so that the spring force of the spring 103 and the hydraulic pressure caused by the hydraulic pressure of the back pressure chamber 105 are balanced, and the spool 96 is moved to a position where the input port 97 and the output port 98 are communicated with each other, and the output port 98 is connected to the input port. 97 and the release port 99, and the position where the output port 98 is communicated with the release port 99, thereby controlling the oil pressure in the upstream portion 34a of the branch oil passage 34 and controlling the oil pressure in the downstream portion 34b, that is, the common oil passage. 93.

Next, the operation of this embodiment will be explained. In the phase control means 10, the hydraulic pressure acting on the piston 21 due to the hydraulic pressure in the hydraulic chamber 20 and the spring force of the return spring 22 that biases the piston 21 are balanced. By moving the piston 21 to the position, the rotational phase of the crankshaft and the valve drive camshaft 9, that is, the opening and closing timing of the intake valve 5 is continuously controlled. For this purpose, the hydraulic pressure acting on the hydraulic chamber 20 may be continuously changed. The hydraulic control valve 14 is movable in the axial direction between a refueling position, a cutoff position, and a release position, and is attached to a spool 41 that is slidably fitted into the housing 40 and is moved toward the refueling position by a spring 49. While applying a spring force, the force due to the hydraulic pressure of the back pressure chamber 51 and the axial thrust of the linear solenoid 42 are applied toward the release position side,
The system is configured to continuously control the hydraulic pressure in the hydraulic chamber 20 by the balance of these forces, and the hydraulic pressure in the hydraulic chamber 20 can be controlled by simply changing the amount of electricity input to the linear solenoid 42, such as the applied current. It is possible to change it continuously.

As another embodiment of the present invention, as shown in FIG. 9, the spool 41 is urged toward the refueling position by the spring force of the spring 49' and the axial thrust of the linear solenoid 42', and the output port 44 The hydraulic control valve 14' may be configured to bias the spool 41 toward the release position using the hydraulic pressure PC as back pressure. In this case, the hydraulic pressure PC output from the output port 44 and the current applied to the linear solenoid 42' I
The relationship with is shown in FIG.

In the above embodiment, the hydraulic power source is the pump P that pumps up hydraulic oil from the oil bath 32 as an oil tank provided in the cylinder head 1. The hydraulic power source may be a pump that pumps up hydraulic oil from an oil pan serving as a tank. Furthermore, the present invention can also be implemented in connection with an exhaust valve as an engine valve.

[0058]

As described above, according to the first feature of the present invention, a hydraulic control valve includes a housing having an input port communicating with a hydraulic pressure source, an output port communicating with a hydraulic chamber, and a release port communicating with an oil tank; Slides into the housing and is axially movable between a refueling position that communicates the input port with the output port, a blocking position that isolates the input port, output port, and release port from each other, and a release position that communicates the output port with the release port. A spool that is freely fitted, a spring that is interposed between the housing and one end of the spool to bias the spool toward the refueling position, and a spring that biases the spool in one of its axial directions. A back pressure chamber communicating with the output port is formed with the other end of the spool facing to exert hydraulic pressure toward the release position, and the actuator is in the operating position. Since the structure is configured to exert a thrust corresponding to the amount of input electricity regardless of the amount of electricity input, the oil pressure in the hydraulic chamber can be continuously changed by simply changing the amount of electricity input to the actuator, thereby controlling the crankshaft and valve train. It becomes possible to continuously change the rotational phase between the camshafts.

According to the second feature of the present invention, since the actuator is a linear solenoid, the characteristics required for the actuator can be easily obtained.

According to the third feature of the present invention, a certain gap is set between the spool in the cutoff position and the actuator in the non-operating state, so that the unstable region peculiar to linear solenoids is avoided. This allows the linear solenoid to exert axial thrust only in the stable region.

Furthermore, according to the fourth feature of the present invention, since the output port is communicated with the back pressure chamber via the orifice,
It is possible to prevent hydraulic fluctuations on the hydraulic chamber side from directly acting on the back pressure chamber and adversely affecting the operation of the hydraulic control valve.

[Brief explanation of the drawing]

FIG. 1 is an overall vertical sectional side view of an embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view of the phase control means.

FIG. 3 is an axial thrust characteristic diagram corresponding to applied current of a linear solenoid.

FIG. 4 is an axial thrust characteristic diagram corresponding to the stroke of a linear solenoid.

FIG. 5 is a simplified diagram showing the force acting on the spool of the hydraulic control valve.

FIG. 6 is a diagram showing the relationship between applied current to a linear solenoid and oil pressure.

FIG. 7 is an enlarged sectional view of a contact portion between a linear solenoid and a spool.

FIG. 8 is an enlarged vertical sectional view of lift amount control means.

FIG. 9 is a diagram corresponding to FIG. 5 of another embodiment of the present invention.

10 is a diagram corresponding to FIG. 6 of the hydraulic control valve of FIG. 9; FIG.

[Explanation of symbols]

5 Intake valve 9 as an engine valve Valve drive camshaft 10
Phase control means 13
Operating mechanism 14, 14' Hydraulic control valve 20 Hydraulic chamber 21 Piston 32
Oil bath 40 as an oil tank
Housing 41
Spools 42, 42' Linear solenoid 43 as actuator Input port 44
Output port 45
Release port 49, 49' Spring 50 Orifice 51
Back pressure chamber 54 void

Claims (4)

[Claims] Claim 1: Between a valve drive camshaft (9) and a crankshaft for driving an engine valve (5) supported in an openable and closable manner on the engine body (E), a valve drive is provided according to the axial movement position. A piston that can control the rotational phase of the camshaft (9) and the crankshaft, has one axial end face facing the hydraulic chamber (20), and is biased by a spring in a direction that reduces the volume of the hydraulic chamber (20). (21); and hydraulic control valves (14, 14') that control the hydraulic pressure in the hydraulic chamber (20).
) In a valve train for an internal combustion engine in which a phase control means (10) is interposed, the hydraulic control valve (14, 14') includes an input port (43) communicating with a hydraulic pressure source (P), a hydraulic chamber (
20) leading to the output port (44) as well as the oil tank (
a housing (40) with a release port (45) leading to the input port (43) and an output port (44);
a refueling position where the input port (43), the output port (44) and the release port (45) are separated from each other, and a blocking position where the output port (44) is connected to the release port (
The spool (45) is slidably fitted into the housing (40) and is axially movable between release positions communicating with the spool (45).
1), a spring (49, 49') interposed between the housing (40) and one end of the spool (41) to bias the spool (41) toward the refueling position, and a spool (41);
41) and an actuator (42, 42') that exerts an actuating force to urge it in either one of the axial directions, and a back pressure chamber (51) communicating with the output port (44) is directed toward the release position. Spool (41) to exert all the hydraulic pressure
The actuator (4) is formed with the other end facing
2, 42') is a valve train for an internal combustion engine, characterized in that it is configured to exert a thrust corresponding to an input amount of electricity regardless of the operating position. [Claim 2] The actuator (42, 42')
The valve operating system for an internal combustion engine according to claim 1, wherein is a linear solenoid. [Claim 3] A spool (41) in a blocking position;
3. The valve operating system for an internal combustion engine according to claim 2, wherein a gap (54) is provided at a constant interval between the actuators (42, 42') in a non-operating state. 4. The valve operating system for an internal combustion engine according to claim 1, wherein the output port (44) is communicated with a back pressure chamber (51) via an orifice (50).