JPH10121929A - Valve system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissolve delay of a movable timing of a movable member by arranging a bypass passage in an operating oil intake/exhaust circuit, and supplying operating oil from a feed source into a hydraulic chamber through the bypass passage while opening a drain passage when a feed passage is closed. SOLUTION: In a condition in which a feed passage 72 is closed and operating oil is not supplied into a hydraulic chamber 13, an intake valve 2 is continuously stopped in a condition in which an intake hole 81 is closed. In the condition, when the feed passage 72 is opened and a drain passage 73 is closed by a three- way valve 75, hydraulic fluid is supplied from an oil pump 71 into the hydraulic chamber through a feed port 1a so as to improve pressure in the hydraulic chamber 13. As a result, a mode becomes a valve opening/closing mode which a plate 6 is engaged with an annular groove 52 of a slider 5. When the feed passage 72 is closed and the drain passage 73 is opened by the three-way valve 75, operating oil is supplied into the feed port 1a and the hydraulic chamber 13 through the bypass passage 74 so as to dissolve delay of a movable timing of the plate 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve train which can switch between two modes of opening and closing an intake / exhaust valve of an engine or keeping the valve closed.

[0002]

2. Description of the Related Art Conventionally, as this type of valve train, there is known a valve train disclosed in Japanese Utility Model Laid-Open Publication No. 61-12912. This includes a valve lifter slidably supported by an engine cylinder head, a valve stem slidably supported by the valve lifter, and a valve stem and a valve lifter slidably disposed between the valve lifter and the valve stem. A movable member that regulates or permits relative sliding of the movable member, a hydraulic chamber formed in the valve lifter to move the movable member, and a supply source that generates hydraulic oil supplied to the hydraulic chamber,
A hydraulic oil supply / discharge circuit for controlling the supply / discharge of hydraulic oil from the supply source to the hydraulic chamber.

In this conventional device, a hydraulic oil supply / discharge circuit includes a supply passage for supplying hydraulic oil from a supply source to a hydraulic chamber,
It consists of a drain passage that opens the hydraulic chamber to the atmosphere, and an on-off valve that opens and closes the supply passage and the drain passage, respectively.
With the supply passage open and the drain passage closed, hydraulic fluid is supplied to the hydraulic chamber to increase the pressure in the hydraulic chamber, thereby moving the movable member so that relative sliding between the valve lifter and the valve stem is allowed, Close the supply passage and open the drain passage, stop the supply of hydraulic oil to the hydraulic chamber, open the hydraulic chamber to the atmosphere, and reduce the pressure in the hydraulic chamber, thereby moving the movable member between the valve lifter and the valve stem. It was moved so that sliding was restricted.

[0004]

However, in the above-described conventional apparatus, since the hydraulic chamber is formed in the cylinder head and the valve lifter, when the supply of the hydraulic oil to the hydraulic chamber is stopped by closing the supply passage, When the valve lifter slides on the cylinder head, the hydraulic oil in the hydraulic chamber may leak from the clearance between the valve lifter and the cylinder head, and air may enter the hydraulic chamber. For this reason, when the supply passage is opened and the hydraulic oil is supplied to the hydraulic chamber to move the movable member, the time required for the pressure in the hydraulic chamber to rise due to the air in the hydraulic chamber becomes longer, and the movable member is moved. As a result, a delay occurs between the predetermined timing to be performed and the timing when the movable member actually moves.

Therefore, an object of the present invention is to eliminate a delay in the movable timing of the movable member.

[0006]

According to the present invention, there is provided a hydraulic oil supply / discharge circuit having a bypass passage for supplying hydraulic oil from a supply source to a hydraulic chamber. In addition, when the supply passage is closed, the drain passage is opened, and hydraulic oil is supplied from the supply source to the hydraulic chamber via the bypass passage.

According to this technical means, when the supply passage is closed, even if the hydraulic oil in the hydraulic chamber leaks, the hydraulic oil continues to be supplied to the hydraulic chamber via the bypass passage, so that air enters the hydraulic chamber. I will not do it. Therefore, the time required for increasing the pressure in the hydraulic chamber when the supply passage is opened does not become longer due to the intrusion of air into the hydraulic chamber, and as a result, a delay in the movable timing of the movable member can be eliminated.

[0008] More preferably, a throttle member provided on the second supply passage is provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the present invention will be described with reference to FIG.

As shown in FIG. 1, a valve train 1 is provided between an intake valve 2 of an engine and a cam 3 supported on a camshaft (not shown).
Move according to the rotation of the valve lifter 4,
It has a slider 5, a plate 6, and a hydraulic oil supply / discharge circuit 7.

The intake valve 2 opens and closes an intake hole 81 formed in the engine combustion chamber formed in the cylinder head 8 by a valve portion 21 thereof. Supported. The shaft portion 21 of the intake valve 2 is formed in the cylinder head 82 in the cylinder hole 82 coaxially with the intake valve 8, with one end (upper side shown in FIG. 1) opening so as to face the cam 3. The intake valve 2 extends through a bottom wall 82a (lower side in FIG. 1), and one end of the intake valve 2 is locked by a retainer 23 fixed to a shaft portion 21 of the intake valve 2 via a cotter 22. Further, the other end receives the urging force of the spring 9 locked to the bottom wall 82a on the other end side of the cylinder hole 82, so that the valve portion 24 and the seat surface 81a of the intake hole 81 contact to close the intake hole 81. Direction (Fig. 1
(Shown above).

The valve train 1 is housed in a cylinder hole 82. The valve lifter 4 of the valve train 1 is slidably supported by the cylinder head 8 in the cylinder hole 82 in the axial direction of the intake valve 2. The valve lifter 4 includes a cylindrical outer body 41 having a bottom wall 41a facing the cam 3 at one end and an opening at the other end, an inner body 42 fixed inside the outer body 41, and a bottom wall 41a of the outer body 41. The outer shim 43 is in contact with the outer shim 43. The outer shim 43 adjusts the clearance between the base circle of the cam 3 and the valve train 1. The outer diameter of the outer body 41 is adjusted by adjusting the outer diameter of the cylinder hole 82 to secure the sliding of the valve lifter 5 with respect to the cylinder head 8. It is slightly smaller than the diameter. The inner body 42 has a first support through-hole 42 a coaxial with the intake valve 2 extending in the axial direction of the intake valve 2 and a second support through-hole 4 a extending in a direction orthogonal to the axial direction of the intake valve 2.
2b. Further, the valve lifter 4 receives the urging force of the spring 10 having one end locked to the inner body 42 and the other end locked to the bottom wall 82a, so that the outer shim 43 comes into contact with the cam 3 (the spring 9 of the intake valve 2). (Upward in FIG. 1 in the same direction as the biasing direction). Note that the outer body 41 and the inner body 42 may have an integral structure.

The slider 5 of the valve train 1 has a support through hole 4
The intake valve 2 is slidably supported in the valve lifter 4 in the axial direction of the intake valve 2 within 2a. The slider 5 has a hole 51 for receiving the tip of the shaft 21 of the intake valve 2. The shaft 21 is press-fitted into the hole 51,
The slider 5 is fixed to the intake valve 2. In the outer periphery of the slider 5, an annular groove 5 that can face the support through hole 42b
2 are formed. The slider 5 has one end locked to the bottom wall 41a of the valve lifter 4 and the other end
The valve portion 24 of the intake valve 2 and the seat surface 81a of the intake hole 81 are separated from each other by receiving the urging force of the spring 11 locked to the opening 11 and are always urged in a direction to open the intake hole 81 (downward in FIG. 1). ing. The biasing force of the spring 11 is set smaller than the biasing force of the spring 9.

The plate 6 of the valve train 1 has a support through hole 4
2a, and the support through-hole 42b
Is slidably supported by the valve lifter 4. The plate 6 has substantially the same thickness as the width of the annular groove 52 of the slider 5 and has a through hole 61 through which the slider 5 is inserted. This allows the plate 6 to be freely disengageable at the edge surfaces of the annular groove 52 and the through hole 61 in a positional relationship in which the annular groove 52 and the support through hole 42b face each other due to the sliding. The engagement and disengagement of the plate 6 and the annular groove 52 allows or restricts relative sliding between the valve lifter 4 and the slider 5. Also, this plate 6
The engagement with the annular groove 52 is released (leftward in FIG. 1) by receiving the urging force of the spring 12 locked to the outer body of the valve lifter 4 and the other end locked to one end surface of the plate 6. Always energized. Further, the other end surface of the plate 6 and the wall surface of the support through hole 42b form a hydraulic oil supply / discharge circuit 7
A hydraulic chamber 13 connected to the cylinder head 1 via a supply port 1a formed in the cylinder head 1 is defined.

The hydraulic oil supply / discharge circuit 7 includes an oil pump 71,
It has a supply passage 72, a drain passage 73, and a bypass passage 74. The oil pump 71 is for supplying hydraulic oil to the lubricating parts for lubricating each part of the engine. The supply passage 72 connects the oil pump 71 and the supply port 1 a via a three-way valve 75, and supplies hydraulic oil to the hydraulic chamber 13. The drain passage 73 is connected to the supply port 1a via a three-way valve 75, and opens the hydraulic chamber 13 to the atmosphere to
The hydraulic oil supplied to the tank is discharged. The three-way valve 75 opens and closes the supply passage 72 and the drain passage 73,
When the supply passage 72 is opened, the drain passage 73 is closed, and when the supply passage 72 is closed, the drain passage 73 is opened. The bypass passage 74 bypasses the three-way valve and directly connects the oil pump 71 and the supply port 1 a to supply hydraulic oil to the hydraulic chamber 13. An orifice portion 76 is provided in the bypass passage 74.

Next, the operation will be described.

FIG. 1 shows a state in which the supply passage 72 is closed and no hydraulic oil is supplied to the hydraulic chamber 13. In this state, the plate 6 is urged to the left as shown in FIG.
The engagement with the annular groove 52 is released. This allows
Even when the cam 3 rotates and the valve lifter 4 is slid in the vertical direction as shown in FIG. 1, the relative sliding between the valve lifter 4 and the slider 5 is allowed, so that the slider 5 does not slide with the valve lifter 4. The intake valve 2 is operated by the urging force of the spring 9 without opening the intake hole 81.
1a and the valve portion 24 are kept in contact with each other, and the stop is continued in a state where the intake hole 81 is closed (valve stop mode).

In this state, when the supply passage 72 is opened and the drain passage 73 is closed by the three-way valve 75,
Hydraulic oil is supplied from the oil pump 71 to the hydraulic chamber 13 via the supply port 1a, and the pressure in the hydraulic chamber is increased. Thereby, the plate 6 is slid rightward in FIG. 1 against the urging force of the spring 12 and engages with the annular groove 52 of the slider 5. As a result, when the valve lifter 4 is slid in the vertical direction as shown in FIG. 1 by the rotation of the cam 3, the relative sliding between the valve lifter 4 and the slider 5 is regulated. The valve 2 is slid in the vertical direction shown in FIG. 1, and the seat surface 81a and the valve portion 24 are separated or come into contact with each other to open and close the intake hole 81 (bubble opening and closing mode). Also, the supply passage 72 is provided by the three-way valve 75.
Is closed and the drain passage 73 is opened, the supply of hydraulic oil from the oil pump 71 to the hydraulic chamber 13 is stopped, and the pressure in the hydraulic chamber decreases. Thereby, the plate 6 is slid to the left as shown in FIG. 1 by the urging force of the spring 12, and the engagement with the annular groove 52 of the slider 5 is released. As a result, as described above, the mode is the valve stop mode.

The supply passage 72 is closed and the drain passage 73 is closed.
Is opened, hydraulic oil is supplied to the supply port 1a and the hydraulic chamber 13 from the oil pump 71 via the bypass passage 74. At this time, since the drain passage 73 is open, the pressure in the hydraulic chamber 13 does not increase so much as to slide the plate 6 against the urging force of the spring 12. Thereby, even if the hydraulic oil in the hydraulic chamber 13 or the supply port 1a leaks out of the clearance between the outer surface of the valve lifter 4 and the inner surface of the cylinder hole 82 due to the sliding of the valve lifter 4, the oil is supplied through the bypass passage 74. As a result, the working oil is replenished accordingly, and air does not enter the hydraulic chamber 13 or the supply port 1a. Therefore, when the supply passage 72 is opened to supply the hydraulic oil to the hydraulic chamber 13 to move the movable member 6, the time required for the pressure increase in the hydraulic chamber 13 is not affected by the presence of air. It does not become long due to the intrusion of air into the hydraulic chamber 13. As a result, the delay of the movable timing of the plate 6 is eliminated, and the mode switching failure due to the movement of the plate 6 and the deterioration of the durability due to the collision between the plate 6 and the bubble lifter 4 are prevented.

The amount of hydraulic oil supplied through the bypass passage 74 is suppressed to the minimum necessary and sufficient to fill the hydraulic chamber 13 and the supply port 1a by the orifice 76. There is no hindrance to lubrication of each component of the engine, such as a shortage of hydraulic oil supplied to each component.

The above operations are tabulated below.

[0022]

[Table 1]

A second embodiment according to the present invention will be described with reference to FIG.

As shown in FIG. 2, the valve gear 1 is disposed between an intake valve 2 of an engine and a cam 3 supported on a camshaft (not shown).
Move according to the rotation of the valve lifter 4,
It has a slider 5, a plate 6, and a hydraulic oil supply / discharge circuit 7. The components other than the hydraulic oil supply / discharge circuit 7 are the same as those in the first embodiment, and thus the description thereof is omitted, and the hydraulic oil supply / discharge circuit 7 will be described below.

The hydraulic oil supply / discharge circuit 7 includes an oil pump 71, a supply passage 72, a drain passage 73, and a bypass passage 74, as in the first embodiment. The oil pump 71 is for supplying hydraulic oil to the lubricating parts for lubricating each part of the engine. The supply passage 72 is provided between the oil pump 71 and the supply port 1a.
Are connected via an on-off valve 77 to supply hydraulic oil to the hydraulic chamber 13. The drain passage 73 is connected to the supply port 1a via an on-off valve 78, and opens the hydraulic chamber 13 to the atmosphere to discharge the hydraulic oil supplied to the hydraulic chamber 13. The on-off valve 77 opens and closes the supply passage 72, and the on-off valve 78 opens and closes the drain passage 73.
When the supply passage 72 is opened by the on-off valve 77, the drain passage 73 is closed by the on-off valve 78. On the contrary, when the supply passage 72 is closed by the on-off valve 77, the drain passage 7 is closed.
3 is opened by the on-off valve 78. The bypass passage 74 is
Oil pump 71 and supply port 1a bypassing opening / closing valve 77
Are connected directly to supply hydraulic oil to the hydraulic chamber 13. An orifice portion 76 is provided in the bypass passage 74.

Next, the operation will be described.

FIG. 2 shows a state in which the supply passage 72 is closed and no hydraulic oil is supplied to the hydraulic chamber 13. In this state, the plate 6 is urged to the left as shown in FIG.
The engagement with the annular groove 52 is released. This allows
Even when the cam 3 rotates and the valve lifter 4 is slid in the vertical direction shown in FIG. 2, the relative sliding between the valve lifter 4 and the slider 5 is allowed, so that the slider 5 does not slide with the valve lifter 4. The intake valve 2 is operated by the urging force of the spring 9 without opening the intake hole 81.
1a and the valve portion 24 are kept in contact with each other, and the stop is continued in a state where the intake hole 81 is closed (valve stop mode).

In this state, the supply passage 72 is opened by the on-off valve 77 and the drain passage 73 is opened by the on-off valve 78.
Is closed, hydraulic oil is supplied from the oil pump 71 to the hydraulic chamber 13 via the supply port 1a, and the pressure in the hydraulic chamber is increased. Thereby, the plate 6 is slid rightward in FIG. 2 against the urging force of the spring 12 and engages with the annular groove 52 of the slider 5. As a result, when the valve lifter 4 is slid in the vertical direction shown in FIG. 2 by the rotation of the cam 3, the relative sliding between the valve lifter 4 and the slider 5 is restricted. The valve 2 is slid up and down as shown in FIG.
The intake port 81 opens and closes due to the separation and contact between the valve a and the valve portion 24 (bubble opening and closing mode). When the supply passage 72 is closed by the on-off valve 77 and the drain passage 73 is opened by the on-off valve 77, the supply of the hydraulic oil from the oil pump 71 to the hydraulic chamber 13 is stopped, and the pressure in the hydraulic chamber is reduced. As a result, the plate 6 is slid to the left as shown in FIG. 2 by the urging force of the spring 12, and the engagement with the annular groove 52 of the slider 5 is released. As a result, as described above, the mode is the valve stop mode.

When the supply passage 72 is closed with the on-off valve 77 and the drain passage 73 is opened by the on-off valve 78, the supply port 1 a and the hydraulic chamber 13 are supplied with hydraulic oil from the oil pump 71 through the bypass passage 74. Is supplied. At this time, since the drain passage 73 is open, the hydraulic chamber 13
Is not so high that the plate 6 slides against the urging force of the spring 12. Thereby, even if the hydraulic oil in the hydraulic chamber 13 or the supply port 1a leaks out of the clearance between the outer surface of the valve lifter 4 and the inner surface of the cylinder hole 82 due to the sliding of the valve lifter 4, the oil is supplied through the bypass passage 74. The supply of the hydraulic oil 13 and the supply port 1
Air does not enter a. Therefore, the supply passage 72
When the movable member 6 is moved by supplying hydraulic oil to the hydraulic chamber 13 by opening the hydraulic chamber 13, the time required for increasing the pressure of the hydraulic chamber 13 is not affected by the presence of air.
No longer due to the intrusion of air into the air. As a result, the delay of the movable timing of the plate 6 is eliminated, and the mode switching failure due to the movement of the plate 6 and the deterioration of the durability due to the collision between the plate 6 and the bubble lifter 4 are prevented.

The amount of hydraulic oil supplied through the bypass passage 74 is suppressed to the minimum necessary and sufficient to fill the hydraulic chamber 13 and the supply port 1a by the orifice 76. There is no hindrance to lubrication of each component of the engine, such as a shortage of hydraulic oil supplied to each component.

The above operations are tabulated below.

[0032]

[Table 2]

The orifice 76 provided in the bypass passage 74 may be anything as long as it reduces the open area of the bypass passage 74, and may be an on-off valve instead of the orifice 76.

[0034]

According to the present invention, since the bypass passage is provided separately from the supply passage, the hydraulic oil can be supplied to the hydraulic chamber even when the supply passage is closed. Even if hydraulic oil leaks when supply of hydraulic oil to the chamber is stopped, air can be prevented from entering the hydraulic chamber. As a result, when the supply passage is opened and the hydraulic oil is supplied to the hydraulic chamber to move the movable member to move the movable member, the time required for the pressure increase does not become longer due to the intrusion of air into the hydraulic chamber. The delay of the movable timing can be eliminated.

According to the present invention, when the hydraulic oil is supplied to the hydraulic chamber via the bypass passage, the drain passage is open, so that the hydraulic oil is supplied to the hydraulic chamber. Nevertheless, the pressure in the hydraulic chamber does not increase. Thereby, it is possible to prevent the movable member from being carelessly moved.

Further, according to the present invention, the throttle member is provided in the bypass passage, so that the amount of hydraulic oil supplied to the hydraulic chamber via the bypass passage can be suppressed to the minimum necessary. As a result, the amount of hydraulic oil supplied from the supply source to other engine components does not decrease unnecessarily.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a valve train according to the present invention.

FIG. 2 is a sectional view showing a second embodiment of the valve train according to the present invention.

[Explanation of symbols]

 Reference Signs List 8 cylinder head 4 valve lifter 5 slider 6 plate (movable member) 7 hydraulic oil supply / discharge circuit 13 hydraulic chamber 71 oil pump (supply source) 72 supply passage 73 drain passage 74 bypass passage 75 three-way valve (open / close valve) 76 orifice (throttle) Members) 77, 78 On-off valve

Claims (2)

[Claims] 1. A valve lifter slidably supported by a cylinder head of an engine, a valve stem slidably supported by the valve lifter, and movably disposed between the valve lifter and the valve stem. A movable member that regulates or permits relative sliding between the valve stem and the valve lifter; a hydraulic chamber formed on the valve lifter for moving the movable member; and a supply that generates hydraulic oil supplied to the hydraulic chamber. A hydraulic fluid supply / discharge system comprising a supply source, a supply passage for supplying hydraulic oil from the supply source to the hydraulic chamber, a drain passage for opening the hydraulic chamber to the atmosphere, and an on-off valve for opening and closing the supply passage and the drain passage, respectively. A valve train having a circuit, wherein a bypass passage for supplying hydraulic oil from the supply source to the hydraulic chamber is provided in the hydraulic oil supply / discharge circuit,
A valve train, wherein the drain passage is opened when the supply passage is closed, and hydraulic oil is supplied from the supply source to the hydraulic chamber via the bypass passage. 2. The valve train according to claim 1, further comprising a throttle member provided on the bypass passage.