JPS59113220A - Apparatus for driving variable valve mechanism - Google Patents

Abstract

PURPOSE:To reduce power loss of a pump in a resistance valve unit for feeding oil not supplied to a cylinder of a variable valve mechanism to various sliding parts of an engine, by employing such an arrangement that the valve opening pressure is variable and a valve of the resistance valve unit is opened at a low pressure when the engine speed is low. CONSTITUTION:The operation of an intake valve and an exhaust valve is controlled by feeding oil to a hydraulic cylinder 50 and using a high-speed cam 61 or a low-speed cam 62 selectively. Oil not supplied to the hydraulic cylinder 50 is passed through a resistance valve unit 11 and supplied to various sliding parts of an engine via a passage 12. A valve body 13 of the resistance valve unit 11 is opened depending on the pressure in a piston chamber 17. When the hydraulic pressure is lowered and a spool valve 21 is moved to the left, supply of oil to the piston chamber 17 is stopped, so that the valve body 13 is opened even at a low pressure due to drop of pressure in the chamber 17. Therefore, it is enabled to reduce the power loss of a pump.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive device for a variable valve mechanism that switches intake and exhaust valves and a cam mechanism that opens and closes them depending on the engine speed, and in particular, the present invention relates to a drive device for a variable valve mechanism that switches intake and exhaust valves and a cam mechanism that opens and closes them depending on the engine speed. Resistance valve unit, l-, which feeds water to each sliding part of the engine.
This is related to the improvement of.

Conventionally, in variable valve engines in which the opening and closing conditions of on-off valves such as intake valves and exhaust valves of the engine are made variable according to engine operating characteristics, a plurality of cams with different cam globules are connected to each other on the camshaft that operates the on-off valves. The camshaft (or rocker arm) is fixed adjacent to the camshaft (or rocker arm) depending on the operating characteristics of the engine.
Many variable valve engines have been proposed in which the on-off valve is selectively opened and closed by moving the on-off valve. A hydraulic piston connected to the camshaft or rocker arm is used as a means for moving the camshaft or rocker arm, and the hydraulic piston itself is driven by oil discharged from an oil pump driven in accordance with the rotation of the engine. Ru. Furthermore, this discharged oil is generally also used to lubricate each moving part of the engine. Generally, when the engine speed is relatively low, the entire amount of discharged oil is used to lubricate each sliding part of the engine. Therefore, when the hydraulic piston is driven to move the camshaft, mouth, or car arm in such an external engine state, the oil discharged from the oil pump is used not only to lubricate each sliding part of the engine, but also to drive the hydraulic piston. Since the oil is supplied to both hydraulic systems at the same time, the pressure of the oil discharged from the oil pump drops rapidly as soon as the supply to the hydraulic piston begins, and the movement speed of the hydraulic piston becomes extremely slow, causing the engine's intake valve , it takes a very long time to variable control the opening/closing conditions of exhaust valves, etc. This is particularly a serious disadvantage if the operating characteristics of the engine change rapidly, especially if the engine suddenly changes from high-speed operation to low-speed operation. In such cases, the intake valves, exhaust valves, etc. are changed from high-speed cams to low-speed cams, but in doing so, the variable control of the intake valves, exhaust valves, etc. is extremely difficult as described above. If it takes a long time for this to occur, even if the engine is in low-speed operation mode, the movement to the low-speed cam will not be completed, which will impair the engine's driving performance and also have a negative effect on exhaust emissions. be.

However, in order to solve the above problem, the present applicant has already proposed in Japanese Patent Application No. 56-57019 that an oil supply pipe that supplies oil from an oil pump to a hydraulic cylinder that switches and drives a camshaft is installed. We proposed a device that includes a relief valve that allows oil to flow back to the oil pan, and a resistance valve unit that can be set at a low opening pressure to supply oil to each sliding part of the engine.

However, with this device, in the low rotation speed range where there is no need to switch the cam mechanism, such as during idling,
The oil pump increases its discharge pressure to sufficiently open the valve body of the resistance valve unit, and supplies oil to each sliding part. Therefore, during that time, the oil pump substantially opens the valve body. This means that power is being expended to make this happen. In addition, in the above device, if the performance of the starch oil deteriorates due to long-term use, the discharge pressure may not increase sufficiently in the low rotation speed range, and the valve bodies of the resistance valves unit and t may not open. be.

In view of the above points, the present invention makes it possible to open the valve element of the resistance valve unit with low pressure in the low rotational speed range of the engine, thereby reducing the power loss of the oil pump and reducing the performance. This invention was developed with the aim of obtaining a driving device for a variable valve mechanism that can sufficiently open the valve body even when the resistance valve unit is in a state where the valve opening pressure of the valve body of the resistance valve unit is variable. It is a feature.

The present invention will be explained below with reference to illustrated embodiments.

In FIG. 1, an oil pan 1 is filled with oil 2 used for lubricating an engine (not shown). The oil pump 4 is driven to rotate according to the rotation of the engine, and pumps up the oil 2 through the suction pipe 3 and sends it under pressure to the first oil feed pipe 5.

The relief valve unit 7 is communicated with the oil pipe 5 via a branch pipe 6 extending from the oil pipe 5. The relief valve unit and the needle valve 8 on the door are biased by a spring 9, and normally the hydraulic pressure of the branch pipe 6 is adjusted to 5 to 6 9/c.
The initial spring load of the spring 9 was adjusted to maintain IrL2. The return pipe 10 is a relief valve unit, and the oil pump resistance valve unit 11 supplies the remaining oil whose pressure is regulated at the door to each sliding part of the engine using the oil in the oil feed pipe 5 as lubricating oil. The needle valve 13 that opens and closes the passage 12 to each sliding part is biased by a spring 14, and when inactive, the needle valve 13 opens and closes the passage 12 to each sliding part.
5 and the passage 12 and the barrier 11frf. Needle valve 13
The opening pressure of the relief valve unit 1-7 is set lower than that of the relief valve unit 1-7. An annular groove 16 is provided around the needle pal f13 at the connection portion with the passage 12. Oil flowing out from the resistance valve unit 11 is sent to each sliding part (not shown) of the engine via a passage 12.

Piston 18 slidably fitted into piston chamber 17
A spring 14 is loaded between the needle pulp 13 and the pulp 1 depending on the axial position of the piston 718.
The biasing force toward 3 changes. That is,
This changes the valve opening pressure of the pulp 13. Straight arm? Ruto 19? The dee 32 is screwed 9 to regulate the amount of axial movement of the piston 18 and communicate the piston chamber 17 with the outside via the orifice 20. The spool valve 21 is fluid-tightly fitted into the cylinder 22 and is slidable in the axial direction. An annular groove 23 is provided on the outer periphery of the central portion of the spool valve 21, and depending on the position of the spool valve 21, the ports 1-24, 25 provided in the cylinder 22 are communicated with or isolated from each other.

The spring 26 biases the spool valve 21 to the left in the figure, and the biasing force thereof is determined by the set R bolt 27. The left chamber 28 of the cylinder 22 communicates with the annular groove 16 via an oil feed passage 29, and the lubricating oil pressure in the passage 12 that communicates with each sliding part of the engine is guided. On the other hand, port 24
communicates with the inlet 15 of the resistance valve unit 11 via an oil feed path 30, and the port 25 communicates with the piston chamber 17 via an oil feed path 31.

The hydraulic switching valve 40 communicates with a second oil pipe 41 branching from the first oil pipe 5 on the upstream side of the resistance valve unit 11 . The hydraulic switching valve 40 has a third oil pipe 42 communicating with the left chamber 51 of the hydraulic cylinder 50 and a right chamber 52 of the hydraulic cylinder 50.
A fourth oil feed pipe 43 communicating with the oil nozzle 4 and a drain oil feed pipe 44 communicating with the oil nozzle 1 are provided, respectively. The computer 56 records engine speed S1, water temperature S2, and load S3.
Alternatively, the oil pressure switching valve 40 is controlled via the lead wire 57 in response to a signal representative of engine operating conditions such as the oil temperature S4, and a combination of communication between the oil feed pipes 41, 42, 43, and 44 is determined. For this combination of 1,000 turns, oil pipe 41→42.
43→44. There are two selections: 41→43° and 42→44, which are determined by the engine operating conditions. In FIG. 1, the hydraulic switching valve 40 is in the second position where 41→43, 42→44 communicate. The hydraulic piston 53 of the hydraulic cylinder 50 is slidable in a liquid-tight manner by means of a sealing material 54 . One end of the connecting rod 55 is fixed to the hydraulic piston 53.

The camshaft 60 is driven to rotate in synchronization with the rotation of the engine. The high-speed rotation cam 61 and the low-speed rotation cam 62 are
Each of them has a profile that allows the intake and exhaust valve pulp reflux 1 and amount and pulp opening/closing timing to be adapted to high-speed rotation and low-speed rotation. The rocker arm 63 is composed of a cam follower 64, a bush 65, and an arm 66, and the bush 65 is engaged with a rocker shaft 67 so as to be swingable and slidable in the axial direction. Pu, Juro 5 is mouth, Kashaft 67
The one that is positioned by the ratchet and l-68, and the ratchet and toro 8? -Say rule 69 l spring 7 (
The rocker shaft 670 is pressed against the circumferential groove 71 or 72 through the rocker shaft 670. Note that the circumferential groove 71 is used when the high-speed rotation cam 61 is used, and the circumferential groove 72 is used when the low-speed rotation cam 62 is used. 73 is Parpuritsume. Also, the connecting rod 55 has a retainer 74.75.
are fitted at a predetermined distance apart, and a ring 76 is inserted between them via compression springs 78 and 79'.
77 is fitted so as to be movable in the axial direction. Ring 76.
A pin 80 is held between the pins 77 and compressive spring force is transmitted to the bush 65 via the pin 80.

FIG. 2 shows an example of a specific structure of the hydraulic switching valve 40.

Reference numeral 101 denotes a housing provided with a fitting hole 102, into which a spool valve 105 is fitted so as to be movable in an axial direction of the fitting hole 102 in a fluid-tight manner. Housing 101
An annular groove 106° 107, 108, 109, 11 selectively communicates with the fitting hole 102 by a spool valve 105.
0 is set. Annular grooves 106 and 110 are communication holes 1
connected by 11. The annular groove 110 is connected to the oil pipe 44 and communicates with the drain side. The annular groove 107 is the oil pipe 4
2 to the left chamber 51 of the hydraulic cylinder 50.

The annular groove 108 is connected to the oil feed pipe 41 and oil is supplied therefrom. The annular groove 109 is connected to the right chamber 52 of the hydraulic cylinder 50 via the oil feed pipe 43. Spool valve 105
A core 116 is provided at the left end of the core 116 via a connecting member 117. A coil 113 is provided around the core 116,
When the coil 113 is not energized, the spool valve 105
is pressed to the right end position in the figure by a spring 115.

Now, when the spool valve 105 is in the illustrated position, the oil in the oil feed pipe 41 flows through the annular grooves 108 and 109 degrees to the oil feed pipe 43.
It flows into the right chamber 52 of the hydraulic cylinder 50 through the metal. On the other hand, the oil feed pipe 42 communicating with the left chamber 51 of the hydraulic cylinder 50 has annular grooves 107 and 106.

Communication hole 1tt, i-shaped groove 110. It communicates with the drain side via an oil pipe 44. When a switching signal is input to the hydraulic switching valve 40 and the coil 113 is energized, the spool valve 105 compresses the spring 115 and is attracted to the left end side in the figure. In this state, the oil pipe 43 communicating with the right chamber 52 of the hydraulic cylinder 50 is connected to the annular grooves 109, 110. The oil feed pipe 42, which communicates with the drain side through the oil feed pipe 44 and the left chamber 51 of the hydraulic cylinder 50, has annular grooves 107 and 108. Oil is supplied through the oil feed pipe 41, and the hydraulic piston 53 is connected as described above. Move to the right in FIG.

The operation of the apparatus constructed as above is as follows. An oil pump 4 that is rotationally driven according to the rotation of the engine causes the oil 2 in the oil/4'n 1 to pass through the suction pipe 3 and into the first
The oil is fed under pressure to the oil pipe 5. A relief valve unit 7 is attached to the oil supply pipe 5 via a branch pipe 6, and when the oil pressure in the branch pipe 6 is lower than the set pressure of the Sgeling 9, the needle valve 8 will not open, and therefore the branch pipe 6 and the return valve will not open. tube 1
0 is shut off, and the entire amount of oil discharged from the oil pump 4 is sent to the oil feed pipe 5. Conversely, when the oil pressure in the branch pipe 6 becomes higher than the pressure of the spring 9, the needle sib 8 opens and the branch pipe 6 and the return pipe 10 communicate with each other, and as a result, the oil in the oil supply pipe 5 is A part of the oil escapes into the return pipe 10, so that the oil pressure in the oil feed pipe 5 does not exceed a set value (usually 5 to 6'q/am2). A portion of the oil in the oil feed pipe 5 flows through the oil feed pipe 41 into the energized hydraulic pressure switching valve 40 . At this time, the oil feed pipe 41 is communicating with the right chamber 52 of the hydraulic cylinder 50 via the oil feed pipe 43, but since the hydraulic piston 53 is fully stroked to the left in the figure, no more oil is allowed to flow into the right chamber. It cannot flow into the hydraulic piston 52 and acts only as a force to press the hydraulic piston 53 to the left. Therefore, the entire amount of oil in the oil feed pipe 5 is fed under pressure to the resistance valve 11. The oil flowing into the inlet 15 compresses the spring 14 and pushes open the needle valve 13, flows into the annular groove 16, passes through the passage 12, and is supplied to each sliding part of the engine to lubricate them. However, if the engine speed is high,
Since the lubricating oil pressure in the passage 12 is high, the oil pressure in the left chamber 28 of the spool valve 21 is also high. Therefore, the spool valve 21 overcomes the biasing force of the spool ring 26 and moves to the right in the figure, so that the groove 23 communicates with both ports 1-24 and 25, and part of the oil in the inlet 15 is transferred. Oil road 30. Poe 1
-24, annular groove 23° port 25. The oil feed path 31 is energized and the oil flows into the piston chamber 17. Therefore, the oil pressure in the population 15 and the piston chamber 17 become equal, but
Due to the difference between the pressure receiving area of the piston 18 and the piston 18, the piston 18 moves to the left end in the figure. That is, the spring 14 is compressed to press the needle valve 13 to the left end with a predetermined force, and as a result, the needle nozzle 14 maintains a predetermined valve opening pressure, thereby reducing the pressure inside the oil pipe 5. The oil pressure is maintained above the opening pressure of the resistance valve UNI/)11. When a switching signal is input to the hydraulic switching valve 40 in this state, oil suddenly flows into the hydraulic cylinder 50 side, so the oil pipe 5
The oil pressure inside the tank suddenly drops. When this oil pressure becomes lower than the opening pressure of the needle valve 13, the needle valve 13 closes the inlet 15 and temporarily stops oil supply to the passage 12 (about 0.3 seconds). supply substantially the entire amount.

Since the oil pressure in the passage 12 temporarily becomes 0, the oil pressure in the left chamber 28 of the spool valve 21 also becomes 0, and the spool valve 2
1 is moved to the left end in the figure by the spring 26 and the port 1-
24 and 25 are blocked. As a result, the oil supply path 31. The introduction of oil into the piston chamber 17 is stopped, and the piston chamber 1
7, the piston 18 is pushed by the spring 14 and flows out through the orifice 20. However, since the oil flows out through the orifice 20, the piston 18 does not move within the travel time of the hydraulic piston 53 (about 0.3 seconds). The I hill hardly moves, so the opening pressure of the needle valve 13 hardly decreases. When the movement of the hydraulic piston 53 is completed, the oil pressure in the oil feed pipe 5 rises again, the needle valve 13 is pushed open, oil is supplied to the passage 12, and the spool valve 21 moves to the right in the figure. In this way, the supply of lubricating oil to the engine's sliding parts is temporarily stopped, but with journal bearings, even if the oil supply is temporarily stopped, the thickness of the oil film on the sliding parts hardly decreases, so it is not a problem. .

Next, a case where the engine speed decreases (a rotation range in which cam switching is not performed) will be explained with reference to FIG. in this case,
Since the lubricating oil pressure in the passage 12 also decreases, the spool valve 21
is moved to the left end in the figure by the spring 26, and as a result, the introduction of oil into the piston chamber 17 is stopped. At this time, the piston 18 is pushed to the right in the figure by the spring 14, causing it to stutter. The oil in the piston chamber 17 flows out to the outside via the oriice 20. Therefore, the pressing force of the spring 14 against the needle valve 13 becomes very weak, the opening pressure of the needle valve 13 becomes about 0, and the oil pressures of the oil feed pipe 5 and the passage 12 become almost equal. That is, the needle valve 13 opens at a very low valve opening pressure, and the oil pump 4 is driven at an extremely low discharge pressure.

Figure 1 shows that the cam for driving the intake and exhaust valves is a high-speed rotating cam 6.
1 to the low-speed rotation cam 62, when the hydraulic piston 53 moves to the right from this state, the connecting rod 55 also moves to the right, and the compression spring 78 is compressed. . This compressive force is transmitted to the rocker arm 63 via the pin 80, and when it becomes larger than the set value of the ratchet 68, the ? -Le 69
is removed from the circumferential groove 71, and the rocker arm 63 is suddenly moved rightward due to the compression of the compression spring 78. In addition,
Even if the ratchet 6B comes off, the mouth and arm 63 are configured to move only on the common base circle of the high-speed rotation cam 61 and the low-speed rotation cam 62 (not shown). But what about Ratchet 68? - The ring 69 is fitted into the circumferential groove 72, and the low speed rotation cam 62 and cam follower 64 are engaged, and the rocker arm 63 absorbs valve operation suitable for low speed.

This will be transmitted to the exhaust valve. Conversely, the cam 62 for low speed rotation
Switching to the higher speed rotation cam 61 is also performed in the same manner as described above.

As mentioned above, in the low rotation range where the intake and exhaust valves are not switched, the opening pressure of the resistance valve unit I-11 and the needle valve 13 is set to approximately O to allow the lubricating oil to flow, so that the discharge pressure of the oil pump 4 is reduced. It is possible to reduce the power loss and reduce the suction.

Automatic needle valve 1 in high rotation range to switch exhaust valve
The opening pressure of 3 can be increased to operate the resistance valve system and operate the hydraulic piston 53 very quickly.

FIG. 4 shows a second embodiment, which differs from the first embodiment in that the valve opening pressure of the resistance valve unit 11 is controlled by the three-way switching valve 130.
This switching control is performed by the computer 56. The three-way switching valve 130 maintains liquid in a housing 131 and switches the flow path of the oil by rotating a rotor 132 rotatably fitted therein. That is, the housing 131 is provided with switching holes 133.134.1'35, while the rotor 132 is provided with these switching holes 133.134.1'35.
．． A passageway 136 is formed that can selectively communicate with 135;
By rotating the rotor 132 via a pulse motor (not shown) or the like, these switching holes 133, 134, 1
The communication relationship between 35 and passage 136 is switched. The pulse motor and the like are driven by the computer 56 via a conductive wire 1371.

In the illustrated state, the switching hole 133 communicates with the oil pipe 5, the switching hole 134 communicates with the piston chamber 17 via the oil pipe 138, and the switching hole 135 communicates with the oil/4'n 1 via the oil pipe 139. ing. Resistance valve unit l-11-2
Dorno Nurupu 13. Sfring14. The structure of the piston 18 is basically the same as that of the first embodiment.

To explain the operation of the second embodiment having the above configuration, at the position of the rotor 132 of the three-way switching valve 130 shown in FIG. 4, the switching hole 1331 passage 136. Switching hole 13
4. Since the oil pressure of the oil feed pipe 5 is introduced into the piston chamber 17 via the oil feed pipe 138, the piston 18 is pressed to the left end in the figure, and the opening pressure of the needle valve 13 is kept high. When the hydraulic switching valve 40 is switched in this state,
As in the first embodiment, substantially all of the oil discharged from the oil pump 4 is supplied to the hydraulic cylinder 50 side, and the hydraulic piston 53 operates very quickly.

On the other hand, in an engine operating range in which the hydraulic switching valve 40 is not operated, the rotational position of the rotor 132 of the three-way switching valve 130 is switched, and the piston chamber 17, oil feed pipe 138, switching hole 1
34, the passage 136, the switching hole 135, and the oil pipe 139 may be made to communicate with each other.

As a result, the introduction of hydraulic pressure into the piston chamber 17 is stopped, and the oil in the piston chamber 17 flows out to the outside, so that the piston 18 moves to the right end.

As a result, the pressing force of the spring 14 against the needle valve 13 is very weak.
The valve opening pressure becomes approximately 0, and the oil pressures in the oil feed pipe 5 and the passage 12 become approximately equal.

The three-way switching valve 130 is controlled by using lubricating oil pressure to increase the valve opening pressure above a certain value, and by controlling the engine speed to increase the valve opening pressure above a certain value. , or one that controls the valve opening pressure to be high within a certain rotation speed range, or one that uses a load to control the valve opening pressure to be high above a certain value, etc., but it is possible to combine these. is also possible.

FIG. 5 shows a third embodiment of the invention. In this embodiment, the opening pressure of the needle valve 13 is controlled by an electromagnetic solenoid 140.

However, the basic operation is the same as that of the second embodiment, that is, in the low rotation speed range, for example, the presser piston 141 is moved toward the right end in the figure without suction, and the valve opening pressure is kept low. In addition, in a high rotational speed range, the presser piston 141 is attracted, the urging force of the spring 14 is strengthened, and the valve opening pressure is increased.A detailed explanation thereof will be omitted.

As described above, according to the present invention, the valve body of the resistance valve unit can be opened with low pressure in the low rotational speed range of the engine, thereby making it possible to reduce the power loss of the oil pump, and Even if the performance of the oil pump deteriorates, the valve body can be sufficiently opened.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the first embodiment, FIG. 2 is a sectional view showing the hydraulic switching valve, and FIG. 3 is a sectional view showing the engine in the low rotation speed range in the first embodiment. Figure 4 is the second
FIG. 5 is a sectional view showing the third embodiment. 1... Oil pan, 2... Oil, 4... Oil pump, 5... Oil feed 'I, 7... Relief valve unit, 1... (Relief valve), 11... Resistance valve unit l-
113... Valve body (needle pulp), 40... Hydraulic switching valve, 50... Hydraulic cylinder, 60... Cam shirt +-161... Cam for high speed rotation, 62... Cam for low speed rotation , 130... Three-way switching valve, 140... Electromagnetic solenoid. Patent Applicant Japan Auto Parts Research Institute Co., Ltd. Yota Motor Co., Ltd. Patent Application Agent Patent Attorney Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Kyo Nakayama Patent Attorney Akira Yamaguchi Figure 2 44 4J 41 42 C Tsukasu

Claims (1)

[Scope of Claims] 1. A driving device for a variable valve mechanism that switches a cam mechanism that opens and closes intake and exhaust valves according to engine speed, which supplies oil from an oil pump to a hydraulic cylinder of the variable valve mechanism. A relief valve that allows the oil to flow back to the oil pipe is provided in the middle of the oil pipe, and a resistance valve unit that is set at a lower opening pressure than the relief valve and can supply oil to each sliding part of the engine. 1. A driving device for a variable valve mechanism comprising: 1. A driving device for a variable valve mechanism, characterized in that the valve opening pressure of the valve element of the resistor unit 1. is configured to be fully variable. 2. A patent characterized in that the valve opening pressure of the valve body of the resistance valve unit is variable according to the oil pressure downstream of this unit, and when the oil pressure is greater than a set value, the valve opening pressure becomes higher. A drive device for a variable valve mechanism according to claim 1. 3. The drive device for a variable valve mechanism according to claim 1, wherein the valve opening pressure of the valve body of the resistance valve unit is variable via a three-way switching valve. 4. The drive device for a variable valve mechanism according to claim 1, wherein the valve opening pressure of the valve body of the resistance valve unit is variable via an electromagnetic solenoid.