JPH11303614A - Variable valve system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out the conversion of a high lift condition and a low lift condition at an adequate timing, in the system having a lifter mechanism to switch the low lift condition from/to the high lift condition. SOLUTION: This valve system 1 is composed to provide a lifter mechanism 20 to switch a valve 24 to carry out the suction and the exhaust in a low lift condition from/to high lift condition, synchronizing to the movement of a cam shaft 12, in a cylinder head 11. In this case, flow passages 11a and 11b to let flow the oil in the cylinder head 11, and a flow passage 2a to let flow the oil in a cylinder block 2, are made independent perfectly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve system having a lift mechanism for changing a lift amount of a valve by a lifter disposed between a cam of a camshaft and a valve shaft of a valve for performing intake and exhaust. In particular, the present invention relates to a flow path configuration through which oil supplied to the variable valve system flows.

[0002]

2. Description of the Related Art Conventionally, an apparatus having a variable valve mechanism in a vehicle is, for example, a lifter that slides in a hole formed in a cylinder head of an engine as described in Japanese Patent Application Laid-Open No. 8-189316. Are composed of an outer body and an inner body, the upper end surface of the outer body contacts the high-speed cam, and the upper end surface of the inner body contacts the low-speed cam. A plate (a regulating member) that can slide in a direction perpendicular to the valve shaft and regulates the relative movement between the outer body and the inner body is supported by the outer body, and the inner body slides in the outer circumferential groove and the outer circumferential groove. The plate disposed in a possible state can be disengaged from the plate, and the relative movement in the valve axis direction with the outer turbo body is restricted. A pressure source for controlling the sliding of the plate in a direction perpendicular to the valve axis is provided. The pressure source moves the plate to a position where it engages with the outer peripheral groove to open and close the valve in a high lift state, and The mode can be selectively switched to a mode in which the valve is opened and closed in a low-lift state by sliding to a position where the valve is separated from the outer peripheral groove.

[0003] In a vehicle, a flow path through which lubricating oil flows in the engine has a single flow path as shown in FIG.

[0004] In other words, the oil stored in an oil pan disposed below the engine in the vehicle is sucked up by an oil pump via a strainer, and then is supplied to a cylinder block and a cylinder head through an oil filter. In the cylinder block, it is supplied to the crankshaft via a crank journal in the crankshaft and to the piston via a connecting rod. Further, in the cylinder head, the oil supplied to the lifter which operates the camshaft and the valve for intake / exhaust up and down, and supplied to each part of the engine is thereafter accumulated in the oil pan by its own weight.

[0005] The lubrication path for such a single oil system is as follows.
For example, it is disclosed on pages 2-16 of the Soarer New Car Manual (issued by Toyota Motor Corporation in May 1991).

[0006]

However, when a variable valve train is provided in a single oil lubrication path as described above, in particular, diesel engines use light oil, and therefore have a higher oil pressure than gasoline. As a result, sludge is likely to be generated during engine combustion. For this reason, when the oil containing sludge accumulates in the oil pan and the oil is fed to the variable valve mechanism and circulated, the oil containing sludge becomes highly viscous as it deteriorates, and the operating time for lift switching can be properly performed. Disappears.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems, and has a lifter mechanism for switching between a low lift state and a high lift state.
A technical object is to enable switching between a high lift state and a low lift state at an appropriate timing.

[0008]

Means taken to solve the above-mentioned problem is that a lift mechanism for switching a valve performing intake and exhaust between a low lift state and a high lift state in synchronization with the movement of a camshaft is provided by a cylinder. In a variable valve operating system provided in the head, a passage through which oil flows between the cylinder head and the cylinder block is made independent.

With the above configuration, the flow path of the oil flowing between the cylinder head and the cylinder block is made independent, so that the oil in the cylinder head is less liable to be contaminated than the conventional one-system oil flow path and the viscosity is hardly increased. For this reason,
It is possible to switch between the high lift state and the low lift state at an appropriate timing without being affected by the oil viscosity.

In this case, if oil is supplied to at least the lifter mechanism in the cylinder head and is supplied to at least the crankshaft and the piston in the cylinder block, the lifter mechanism uses oil that is less contaminated than before. Since the change of the lift can be performed, the operation time is prevented from being delayed in the change of the lift.

Further, if the valve is switched between a low lift state and a high lift state by oil in the cylinder head,
Oil with less sludge is lubricated, and switching can be performed smoothly with less dirt.

[0012]

Embodiments of the present invention will be described below. As shown in FIG. 8, the variable valve system 1 of the present invention is characterized in that the flow path through which the fluid (oil) flows is completely separated by the cylinder block 2 and the cylinder head 11. Oil is mainly supplied to the camshaft 12 and the lifter 20 of the variable valve apparatus 10.

Therefore, first, the variable valve train 10
Will be described with reference to the drawings. In FIG. 1, a camshaft 12 is rotatably supported by a cylinder head 11 of a vehicle engine. The camshaft 12 is provided with one low-speed cam 13 and high-speed cams 14 and 15 on both sides thereof.

The low speed cam 13 and the high speed cam 1
A lifter 20 interposed between the intake / exhaust valves 4 and 15 and a valve shaft 24 of an intake / exhaust valve has an upper bottom cylindrical shape slidably disposed in a hole 21 formed in the cylinder head 11 in the valve axis direction. The outer body 22 is driven by high-speed cams 14 and 15, and the inner body 23 is driven by the low-speed cam 13. Is done. The stem end surface 24a (valve shaft end surface) of the valve shaft 24 is in contact with the lower surface of the inner body 23 via the shim 25, and receives the driving force of the low speed cam 13 at this portion.

The inner body 23 receives the urging force of the compression spring 27 and is urged toward the low-speed cam 13 by a retainer 52 fixed via a cotter fitted into a groove above the valve shaft by the compression spring 27. Outer turbo day 22
Is a retainer 51 provided below the outer turbo day 22.
As a result, the high-speed cam 1 receives the urging force of the compression spring 28.
It is urged to the 4 and 15 sides.

Outer body 22 and inner body 23
An intermediate body 37 constituted by one or a plurality of members (here, members 37a and 37b) is inserted into an annular space formed therebetween. This intermediate body 37
A pair of substantially rectangular plates (restriction members) 26 slidable in the vertical direction with respect to the valve shaft 24 in the guide space formed by 37a and 37b is sandwiched between 37a and 37b and formed in a direction perpendicular to the valve shaft 24. Are arranged in a state guided by the guide surface 37ca. Further, as shown in FIG. 7, communication holes 37aa and 37aa are formed in the intermediate body 37 in the axial direction.
The communication holes 37aa and 37ba are provided at positions to be opened even when the plate 26 slides along the guide surface 37ca (see FIG. 3). The plate 26 defines a chamber (pressure chamber) 30 that receives pressure in the sliding direction of the plate 26 and a non-pressure chamber 31 that does not normally receive pressure.

The pressure chamber 30 is provided with a fluid passage (flow passage) 11 a provided in the cylinder block 11 through an outer turbocharger 22.
The oil is introduced through the side hole 22a. On the other hand, a compression spring 32 for urging the plate 26 to the left as shown in FIG. 1 is sandwiched in the chamber 31 by a step provided on the side wall of the plate 26, and between the plate 26 and the inner wall of the outer turbo body 22. It is arranged in.

Below the intermediate body 37, a retainer 52 that supports the valve shaft 24 and receives the urging force of the compression spring 27 that urges the inner body 23 upward, and supports the outer peripheral surface of the retainer 51 to raise the outer turbo body 22 upward. A retainer 51 is provided for receiving the urging force of the compression spring 28 for urging.
Between the retainers 51, 52 and the intermediate body 37, fluid accumulated in the moving space 29, which moves when the timing member 36 for controlling the timing of the lifter 20 receives an inertial force, is communicated with the intermediate body 37. Holes 37aa, 3
A chamber 53 that is discharged through 7ba is formed. This chamber 53 is a pressure release chamber that releases pressure to the outside of the lifter through a hole provided on the side of the retainer 51.

The oil discharged from the oil pump 40 is supplied to the fluid passage 11a through a fluid supply / discharge valve (OSV) 41. The fluid supply / discharge valve 41 is controlled by, for example, a controller (not shown). A first position where oil discharged from the pump 40 is supplied to the flow path 11a in accordance with the engine speed, and the oil pan 42 is disconnected from the pump 40 and the flow path 11a. The supply to the passage 11a is shut off, and the switching to the second position for controlling the communication between the passage 11a and the oil pan 42 is controlled.

As shown in FIGS. 2 and 3, the plate 26 is provided with an oil pressure in the pressure chamber 30 and a compression spring 3 in the chamber 31.
It is configured to be slidable in a direction orthogonal to the valve shaft 24 by the repulsive force of 2. FIG. 2 shows a central hole 26C of the plate 26.
3 shows a state in which the center of the center hole 26C of the plate 26 is aligned with the axis of the inner body 23 in the left direction from the axis of the shaft portion 23C of the inner body 23. FIG.

The inner body 23 is, as shown in FIG.
It has a disk-shaped upper end portion 23A that comes into contact with the low-speed cam 13, a disk-shaped lower end portion 23B that comes into contact with the shim 25, and a shaft portion 23C that connects these. The lower end portion 23B has an outer diameter larger than the upper end portion 23A. Is small, and the shaft portion 23C is
Even smaller outer diameter.

The center hole 26C of the plate 26 has a larger inner diameter than the lower end 23B of the inner body 23. When the center of the center hole 26C is aligned with the axis of the inner body 23 as shown in FIG. Lower end 23B
Can enter the central hole 26 </ b> C of the plate 26. The plate 26 serves as a regulating member that regulates the movement of the inner body 23 with respect to the outer turbo body 22 at the shaft portion 23C.

The plate 26 is provided with a central hole 26C having a diameter in a range shifted by the sliding amount of the plate 26 in the valve axis direction. The center of the central hole 26C is coaxial with the valve shaft 24, and has a first circumferential groove 26A on the outside and a second circumferential groove 26B on the inside in an axially symmetric positional relationship as shown in FIGS. Are formed. This first circumferential groove 26A
And the second circumferential groove 26 </ b> B is the shaft portion 2 of the inner body 23.
The protrusion 36a of the timing member 36 held on 3C is a groove to be selectively engaged. Further, the timing member 36 is an annular member having a projection 36a on the lower side capable of engaging with the first circumferential groove 26A and the second circumferential groove 26B, and is provided inside the upper end portion 23A of the plate 26 and the inner body 23. The space between the formed spaces 29 can be moved in the axial direction. In this case, the protrusion 36 of the timing member 36
a may be any shape as long as it can fit in the first circumferential groove 26A and the second circumferential groove 26B.

Next, the operation of the variable valve apparatus 10 will be described. As shown in FIG. 4, the variable valve apparatus 10 is connected to the outer turbo motor 22 in the nose region of the high speed cams 14 and 15 and the low speed cam 13. The low lift state in which the inner body 23 can relatively move, the outer turbo body 22 and the inner body 23
Switch between high-lift states, which are relatively immovable. In the high lift state before switching, as shown in FIG.
The lower end 23B of the inner body 23 is
At a lower position, the inner body 23 and the outer turbo body 22 are lifted so that their respective upper end surfaces coincide with each other and do not move relative to each other. In this state, the projection 36a of the timing member 36 is fitted in the first circumferential groove 26A of the plate 26.

When switching from the high lift state to the low lift state, the fluid supply / discharge valve 41 is switched to the first position, and the oil discharged from the oil pump 40 is supplied to the flow path 11a. Here, the curve indicated by reference numeral 45 in FIG. 5 shows the valve lift state in the high lift state. In this figure, S1 and S2
Are the base circle states with the valves closed, respectively.
S3 is the maximum lift state with the valve fully opened. In switching from the high lift state to the low lift state, in the maximum lift state, the high-speed cams 14 and 15 abut against the outer turbocharger 22 at the tips of the nose regions (portions where the cam diameters are large) of the respective cams. I have.

The curve indicated by reference numeral 46 indicates the cam acceleration, and the cam acceleration coincides with the acceleration of the lifter 20. That is, an upward acceleration is generated at the beginning and immediately before the closing of the valve, and a downward acceleration is generated near the maximum lift state.

With upward acceleration when the lifter 20 moves from the base circular region to the maximum lift state, the projection 36a of the timing member 36 separates from the first circumferential groove 26A due to the inertial force acting on the timing member 36, but the plate 26
Is pressed downward via the intermediate body 37 by the pressing of the outer body 22 by the cam, and therefore does not move in the sliding direction perpendicular to the valve shaft 24. In this case, at an upward acceleration when the lifter 20 shifts from the base circle region to the maximum lift state, the timing member 36 is once separated from the plate 26 by an inertial force.

On the other hand, even when the lifter 20 shifts from the maximum lift state to the base circle, the timing member 36 separates from the plate 26 and the movement space 2 formed in the axial direction.
It moves in the axial direction by an inertial force within 9. Then, when the high speed cams 14 and 15 reach the base circle regions, the upper end surfaces of the inner body 23 and the outer turbo body 22 coincide with each other,
When the driving force of the outer turbo-day 22 does not act on the plate 26, the timing member 36 is detached from the plate 26, and the plate 26 can slide to the right side shown in FIG. At this time, since the oil pressure due to the discharge acts on the pressure chamber 30, the plate 26 is
Slides to the right without interfering with the lower end 23B.
After the plate 26 slides, the timing member 36 falls on the plate by its own weight, and the projection 36a of the timing member 36 and the groove 26B of the plate 26 are engaged when the cam becomes the base circular region.

That is, when the plate 26 is slid rightward (see FIG. 6), the inner body 23 is disengaged from the outer body 22 in the axial direction with the plate 26. The upper body can be moved to the upper position, and the rotation of the high-speed cams 14 and 15 and the low-speed cam 13 causes the inner body 23 and the outer turbo body 22 to enter a low-lift state in which the relative position coincides and the relative position repeats. Become. As described above, the timing member 36 can surely complete the switching from the high-lift state to the low-lift state regardless of the timing at which the discharge fluid pressure is applied.

Next, when switching from the low lift state to the high lift state, first, the supply of the discharge oil pressure is stopped. When the oil pressure due to discharge is not applied to the pressure chamber 30, the force of the compression spring 32 of the non-pressure chamber 31 presses the plate 26 to the left. High speed cam 1 in low lift condition
4 and 15 and the nose area of the low-speed cam 13 are lifters 2
When abutting on 0, the relative positions of the inner body 23 and the outer body 22 are shifted. In a state in which an upward acceleration is applied, the timing member 36 jumps up from the plate 26 in the axial direction due to the inertial force, and the engagement with the plate 26 is released. When the base circular regions of the high-speed cams 14 and 15 and the low-speed cam 13 abut against the lifter 20, the inner body 23 is at the lift position coinciding with the outer turbo body 22, and the lower end 23B of the inner body 23 is
The plate 26 is slidable to the left by detaching from the central hole 26C. At this time, the plate 26 is slid to the left by the compression spring 32, and after the plate 26 slides to the left position, the timing member 36 falls on the plate by its own weight, and when the timing member 36 comes to the base circle area, the timing member 36 The protrusion 36a engages with the groove 26A of the plate 26. That is, the state shown in FIG. 1 is established, and the state is switched to the high lift state in which the relative movement between the inner body 23 and the outer body 22 is prevented.

The configuration and operation of the variable valve operating device 10 have been described above. The variable valve operating device 10 is provided with flow paths 11a and 11b having the configuration shown in FIG. In particular,
Oil is sucked up from an oil pan 42 provided inside or outside the cylinder head 11 by a pump 40 via a strainer 61, and the oil passing through the filter 62
1b each cam journal 12 of the camshaft 12
Supply oil for lubrication to a. At the same time,
The oil that has passed through the filter 62 is supplied to a fluid supply / discharge valve (OSV).
The lifter 20 drives the valve 24 by the low-speed and high-speed cams 13, 14, and 15 by oil supplied from the fluid intake / exhaust valve 41 by energizing the fluid supply / discharge valve 41. Thus, oil is supplied.

The oil supplied to each of the camshaft 12 and the lifter 20 is supplied to the cylinder head 11 by its own weight.
Member 6 disposed between the cylinder block 2 and
The oil that has fallen on the top 3 and has dropped due to its own weight is guided to the oil pan 42 by making the bottom tapered, and is accumulated in the oil pan 42. The structure of the seal member 63 is a general seal member used for a vehicle having a hole formed between the cylinder block 2 and the cylinder head 11 through which oil passes and a hole through which cooling water passes. Can be easily cut off to communicate oil between the cylinder block 2 and the cylinder head 11.

According to the above construction, sludge generated during combustion is suppressed in the cylinder head 11 and oil can be circulated in the cylinder head with less dirt. Is prevented from being affected by oil contamination.

On the other hand, in the cylinder block 2, oil stored in an oil pan 4 disposed below the cylinder block 2 is supplied to an oil pump 6 via a strainer 5.
Sucked up by The oil sucked up by the oil pump 6 passes through the oil filter 7 to remove dirt (sludge and the like). The oil that has passed through the filter 7 is supplied to the peripheral surface of the crankshaft 8 via flow paths provided in the crank journal 8a and the crankpin 8b of the crankshaft 8 and in a path connecting the crank journal 8a and the crankpin 8b. At the same time, the power is supplied to a shaft supporting the piston 3 via a flow path inside the connecting rod 9 rotatably supported by the crank pin 8b. Similarly, the oil supplied to each part of the cylinder block 2 drops by its own weight, is guided to the oil pan 4, and accumulates in the oil pan. However, since combustion gas blows through the cylinder block, deterioration of oil is inevitable.

As described above, the flow paths 11a and 11b through which the oil flows in the cylinder head 11 and the flow path 2a through which the oil flows in the cylinder block 2 are separated from each other. The oil No. 11 is difficult to be stained and hard to increase the viscosity. For this reason,
The switching between the high lift state and the low lift state can be performed at an appropriate timing without being affected by the oil viscosity.

[0036]

According to the present invention, in a variable valve system including a lift mechanism in a cylinder head for switching a valve that performs intake and exhaust in synchronization with movement of a camshaft between a low lift state and a high lift state, the cylinder head and the cylinder By making the flow path of the oil flowing between the blocks independent, the oil in the cylinder head is less likely to be contaminated and harder to have a higher viscosity than the conventional one-system oil flow path. Therefore, switching between the high lift state and the low lift state can be performed at an appropriate timing without being affected by the oil viscosity.

In this case, by supplying oil to at least the lifter mechanism in the cylinder head and supplying oil to at least the crankshaft and the piston in the cylinder block, the lifter mechanism uses oil with less contamination than before. Since the lift can be switched, it is possible to prevent the operation time from being delayed when the lift is switched.

If the valve is switched between the low lift state and the high lift state by the oil in the cylinder head,
Oil with less sludge is lubricated, and switching can be done smoothly with less dirt.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a variable valve apparatus of a variable valve system according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of the lifter shown in FIG.

FIG. 3 is a sectional view of the lifter when the timing member shown in FIG. 2 moves under pressure.

FIG. 4 is a diagram illustrating a relationship between a switching timing of a variable valve operating device of a variable valve operating system and a trajectory of a cam according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a relationship between a lift amount and time and a relationship between cam acceleration and time of the variable valve operating device of the variable valve operating system according to the embodiment of the present invention.

FIG. 6 is a sectional view showing a state where the valve shown in FIG. 1 is opened by a lift.

FIG. 7 is a view illustrating a discharge path of a fluid from a timing member moving space of the variable valve operating device according to the embodiment of the present invention.

FIG. 8 is a schematic diagram showing a configuration of a variable valve system including two oil flow paths according to an embodiment of the present invention.

FIG. 9 is a diagram showing a system configuration including a conventional one-system oil flow path.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Variable valve system 2 Cylinder block 3 Piston 8 Crankshaft 10 Variable valve device 11 Cylinder head 12 Camshaft 20 Lifter (lift mechanism) 24 Valve shaft (valve)

Claims (3)

[Claims] 1. A variable valve system including a lift mechanism in a cylinder head for switching a valve for performing intake and exhaust between a low lift state and a high lift state in synchronization with a movement of a camshaft. A variable valve system wherein an oil flow path is made independent. 2. The variable valve system according to claim 1, wherein oil is supplied to at least the lifter mechanism in the cylinder head, and is supplied to at least a crankshaft and a piston in the cylinder block. 3. The variable valve system according to claim 1, wherein the valve is switched between a low lift state and a high lift state by oil in the cylinder head.