JPS6341612A - Valve driver for engine - Google Patents

Abstract

PURPOSE:To aim at improvement in durability, by installing a driving device, which makes a cam member shift to a driving position, where a valve member is drive by rotation of the cam member, and a nondriving position where the valve member is not driven, in the axial direction, while installing a base circle part in the cam member. CONSTITUTION:A cam member 2 is locked to a camshaft 1, while a cam member 3 is installed there free of slide motion in the axial direction but relatively unrotated. And, this cam member 3 makes a pair of plungers 28 shift to the right by what these plungers press the side of the cam member 3 at the time of pressure oil being taken in the oil passage 24 formed in a central part of the camshaft 1, making them possible to be solidly rotated with the camshaft 1. And, at the time of nonintroduction of the pressure oil, the cam member 3 is made going to the left by a pair of springs 33 via a plunger 35, making a valve 5 keep in a nondriving state. In addition, when the cam member 3 is in a nondriving position, a base circle part 36 is installed at the side of the cam member 3 in succession to the cam member 3 in order to a restraint of the valve 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve drive device for an engine, and in particular, the engagement state between a valve drive cam member and a valve is controlled according to the operating state, thereby controlling the valve operation. This invention relates to an engine valve drive device that controls the engine.

(Prior Art) In the valve drive device of an engine, an engine in which the state of engagement between a valve and a valve drive cam is changed in accordance with the operating state of the engine is conventionally known.

For example, in Japanese Patent Application Laid-Open No. 59-155515, a valve driving cam member is rotatably attached to a camshaft, a plunger for restraining the rotation of the cam member is arranged inside the camshaft, and a hydraulic mechanism is provided. A valve driving device is disclosed in which the radial movement of the plunger is controlled according to the operating condition using the radial direction of the plunger. In this disclosed device, when hydraulic pressure is not acting on the plunger, the spring protrudes from the surface of the camshaft and enters the engagement hole of the cam member due to the elastic force of the spring, causing relative rotation between the cam member and the camshaft. make it impossible. Therefore, in this state, the cam member rotates integrally with the camshaft,
Opens and closes the intake and exhaust valves at predetermined timing.

When hydraulic pressure is applied to the plunger, the plunger sinks into the camshaft, the cam member becomes rotatable relative to the camshaft, and the camshaft idles. In this case, the cam member does not drive the valve and the valve remains closed.

In addition, Japanese Patent Application Laid-open No. 58-91317 discloses that two cams are provided, a high-speed cam and a (1-use cam) for operating one valve, and the cams are selectively operated according to the operating condition. A valve driving device is disclosed.

In this device, a hollow member installed in parallel with a high-speed cam and a low-speed cam is attached to the camshaft so as to be movable in the axial direction, and a switching shaft is provided with a shift fork that switches the cam parallel to the camshaft. By moving the shaft in the axial direction according to the operating condition, switching between the high-speed cam and the low-speed cam is performed via the hub provided in the hollow member mentioned above and engaged with the shift fork. The opening/closing timing is controlled according to the operating conditions.

In this way, the mechanism that controls the state of engagement between the valve member and the cam is used to stop the operation of the valve under certain conditions.
Alternatively, it can be widely applied to various types of control, such as when changing the opening/closing timing of a valve depending on the operating state.

(Problem to be Solved) However, in the structure disclosed in JP-A-59-155515, when the cam member is restrained to the camshaft, the reaction force of the valve operation must be supported only by the plunger. However, it has disadvantages in terms of structure and strength. In this point,
In the device disclosed in Japanese Patent Application Laid-Open No. 58-91317,
The cam can be supported across its entire width, and can also be supported at multiple locations in the circumferential direction so that the valve's operating reaction force is dispersed. This is advantageous compared to what is disclosed in the above publication. However, this JP-A-58-9
The device disclosed in Japanese Patent No. 1317 requires a special switching shaft to which a shift fork is attached in order to switch the cams, so there is a problem that the device becomes large and complicated. In addition, this structure has been developed into a hydraulic lash adjuster (hereinafter referred to as rHLAJ), a valve drive device equipped with a hydraulic lash adjuster device that automatically adjusts the gap between the valve and the cam surface. In this application, the problem is that if the hollow member is moved axially to deactivate the valve, it is impossible to activate the valve again because the HLA mechanism stretches the valve. Therefore,
The device disclosed in Japanese Patent No. 8-91317 has the problem of increasing the size of the device, as well as the problem of not being able to apply control to stop valve operation under specific conditions.

(Means for Solving the Problem) The present invention was constructed in view of the above circumstances, and provides a valve that is compact, has sufficient strength, is durable and highly reliable, and is equipped with an HLΔ mechanism. It is an object of the present invention to provide an engine valve driving device that can be effectively applied to valve operation/stop control.

The valve drive device of the present invention includes: a camshaft that rotates in synchronization with the rotation of an engine; a cam member that is movable in the axial direction of the camshaft and is attached to the camshaft so that it cannot rotate relative to the camshaft; A valve member having a hydraulic lash adjuster device and driven by the cam member; a driving position where the valve member is driven by rotation of the cam member; and a non-driving position where the valve member is not driven even when the cam member rotates. a drive means for moving the cam member in the axial direction; a control means for controlling movement of the valve member in the axial direction according to operating conditions; and a control means provided on the cam member when the cam member is in the drive position. and a base circle portion that engages with the valve member.

According to the present invention, the cam member and the camshaft are constructed separately, and the two are coupled, for example, by spline engagement. Therefore, the cam member rotates integrally with the camshaft, but can move independently in the axial direction of the camshaft. In this case, the cam member moves in the axial direction between a drive position in which the valve member is opened and closed by rotation and a non-drive position in which the valve member is not driven by rotation. In the present invention, a control means is provided to control the movement of the cam member in the axial direction according to the operating state. This control means includes a plunger that moves the cam member in a hydraulically operated manner, and is installed inside the camshaft.

Further, the valve member of the present invention is equipped with a hydraulic lash adjuster, that is, a hydraulic lash adjuster, in order to automatically adjust the gap between the abutting portion of the valve tip with the cam member and the cam surface to obtain proper valve operation. It has a structure. Such HLA
In a valve that incorporates a mechanism, when the cam member is moved to the non-driving position, if the valve does not come into contact with the cam, the valve length increases due to the hydraulic pressure and the cam member is moved in the axial direction to drive the valve. It will be impossible to return it to its original position, so
In the present invention, a base circle portion is provided that protrudes from the side of the cam member, and the base circle portion is brought into contact with the tip of the valve member even when the valve member moves to the non-driving position, so that the valve Try not to cause any elongation.

(Effects of the Invention) As described above, according to the present invention, the cam member is engaged with the camshaft over the entire width of the cam member, so that the cam member is engaged with the camshaft over the entire width of the cam member. Unlike the engagement type, it has sufficient structural strength. As a result, a durable and highly reliable valve driving device can be obtained.

Further, since the control means can be incorporated inside the camshaft, the device can be configured compactly. Furthermore, since the cam member is provided with the base circle portion that comes into contact with the valve member in the non-driving position of the cam member as described above, it can be applied without any problem to a valve train having a valve member incorporating an HLA. can.

Therefore, even in a valve train having an HLΔ mechanism, the present invention not only controls changing the opening/closing timing of a valve by switching a cam member having a plurality of cam profiles, but also stops valve operation according to the operating state. It can also be applied to valve stop control.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Referring to FIGS. 1 to 4, the engine valve mechanism of this example includes a camshaft 1 that rotates in synchronization with an engine crankshaft (not shown).

Two cam members 2.3 are attached to the camshaft 1 for one cylinder, the cam member 2 is fixed to the camshaft 1, and the cam member 3 is fixed to the camshaft 1. It is attached to the camshaft 1 in such a structure that it cannot rotate relative to the camshaft 1, but can slide on the camshaft 1 in the axial direction. Valve 4.5 corresponds to each of these cam members 2.3.
will be provided. The valve 4 is provided with a tappet 6 on the top that makes sliding contact with the cam surface of the cam member 2. A valve stem 7 is located below the tappet 6 and has a valve body at its lower end that opens into the combustion chamber.A spring retainer 9 that supports a spring 8 is attached near the upper end of the valve stem 7. There is. An HLA mechanism 10 is provided between the tappet 6 and the valve stem 7 to automatically adjust the gap between the valve 4 and the cam member 4. The HLΔ mechanism 10 has a tappet 6
A plunger 12 is provided on a guide 11 fixed to the plunger 12 so as to be slidable in the vertical direction in FIG. Furthermore, the HLA mechanism 10 includes two oil chambers 13, 14.
These chambers 13 and 14 are partitioned off by an oil passage 15 provided in the plunger 12. A ball 16 is disposed in the oil chamber 14 so as to close the passage 15, and a spring 17 is disposed to support the ball 16. With this configuration,
Oil can flow into chamber 14 from chamber 13, but cannot flow out. As a result, if a gap is created between the tip of the valve stem 7 and the lower end of the plunger 12, the pressure in the oil chamber 13 of the plunger 12 will exceed the pressure in the oil chamber 14, and the ball 16 will be pushed down by this pressure difference, causing the oil to drop. flows into the oil chamber 14 through the passage 15. This causes the plunger 12 to project downward and come into contact with the tip of the valve stem again to compensate for the gap.

Since the valve 5 has a structure similar to that of the valve 4, the same reference numerals are given to the same members, and the explanation thereof will be omitted. Note that the cuppet 18 of the valve 5 is different from that of the valve 4 in that its top portion is partially cut out.

To explain the structure of the cam member 3 in detail, as shown in FIG. The camshaft 1 is engaged with the camshaft 1. Further, as shown in FIG. 1, an elongated hole 20 extending in the axial direction is formed in the portion of the camshaft 1 that the cam member 3 engages with, and this elongated hole 20 has both leg portions 21 of the cam member 3. A pin 23 connecting the .22 extends through it. Therefore, the axial movement of the cam member 3 is restricted by the elongated hole 20 and the pin 23.

In the valve operating mechanism of this example, a hydraulic mechanism is provided to control the movement of the cam member 3 in the axial direction. To explain this hydraulic mechanism, an oil passage 24 extends in the axial direction at the center of the camshaft 1.
The tip communicates with an oil passage 25 perpendicular to this, and two oil passages 26 and 27 extend diagonally downward from both ends of this oil passage 25 in substantially parallel fashion. A plunger 28.29 is arranged inside these oil passages 26.27, and this plunger 28.29 abuts on one side of the cam member 3 at a position approximately in the vertical direction where the pin 23 is located. ing.

The camshaft 1 also includes an oil passage 2 of the cam member 3.
6.27, on the opposite side these passages 26.2
7 and a pair of elongated holes 30 extending diagonally to one side.
31 is formed. A spring 32.33 and a plunger 34.35 are arranged in the holes 30.31, respectively. These plungers 134.35 abut at substantially symmetrical positions on the opposite side of the cam member from the face on which the plungers 28.29 abut.

With the above configuration, when hydraulic pressure is applied to the oil passage 24, the plungers 28 and 29 press the side surface of the cam member 3 to move it to the right in FIGS. 1 and 2, and the cam member 3
is located on the operating axis of the valve 5. Thereby, the cam member 3 can drive the valve 5 to open and close by rotating integrally with the camshaft 1.

On the other hand, when hydraulic pressure is not introduced into the oil passage 24, the elastic force of the spring 32.33 disposed in the hole 30.31 causes the plunger 34.35 to move the cam member 3 as shown in FIG.
In FIG. 2, the cam member 3 is released from engagement with the valve 5 by pushing leftward. As a result, even if the cam member 3 rotates with the rotation of the camshaft 1, the valve remains in the non-driven state.

In addition, since the valve 5 of this example is equipped with the HLA mechanism 10, when the cam member 3 moves to the non-driving position and the restraint of the valve 5 is released, the plunger 12 of the LA mechanism 10 moves downward. A problem arises in that the position of the top surface of the cuppet 18 rises due to the protrusion, making re-engagement with the cam member 3 impossible. In the structure of this example, in order to ensure that the valve is restrained when the cam member 3 moves in the axial direction and is in the non-driving position, there is a cam surface that is continuous to the cam member 3 on the side of the cam member 3. A base circle portion 36 is provided which has the same outer diameter as the diameter of the base circle. As a result, even if the cam member 3 moves to the non-driving position, the valve 5 is maintained in contact with the base circle portion 36, thereby preventing undue elongation of the valve length by the HLA mechanism 10. It can be prevented. Therefore, with the configuration of this example, valve drive control can be performed while effectively utilizing the advantages of the HLΔ mechanism 10.

Further, in this example, the cam member 3 of the tappet 18 of the valve 5
A part of the side where the valve 5 is engaged and disengaged is cut out, and the distance between the operating axis 37 of the valve 5 and the end face of the tappet 18 is made as small as possible. Thereby, the cam member 3 can be quickly engaged and disengaged, and the durability of the cam member 3 and the tappet 18 can be improved.

[Brief explanation of drawings]

1 is a partial sectional view of a valve driving device for an engine according to an embodiment of the present invention, FIG. 2 is a plan view of the valve driving device of FIG. 1, and FIG. 4 is a view taken along line B-B in FIG. 1. 1...Camshaft, 2.3...Cam member, 4.5...Valve, 6...Tappet, 7...Valve Stem, 8... Spring, 9... Spring holder, 10... HL
Δ mechanism, 11...Guide, 12...Plunger, 13.14...Oil chamber, 1
5...Oil passage, 16...Ball,
17... Spring, 18... Tappet, 1
9...Recess, 20...Elongated hole, 21.2
2... Leg, 23... Pin, 24.2
5.26...Oil passage, 28.29...
... Plunger, 30, 31 ... Hole, 32.3
3... Spring, 34. 35... Plunger, 36... Base circle section, 37...
Actuation axis.

Claims (1)

[Claims] It has a camshaft that rotates in synchronization with the rotation of the engine, a cam member that is movable in the axial direction of the camshaft and is attached to the camshaft so that it cannot rotate relative to the camshaft, and a hydraulic lash adjuster device. A valve member driven by the cam member, a driving position where the valve member is driven by rotation of the cam member, and a non-driving position where the valve member is not driven even when the cam member rotates, the cam member being moved in the axial direction. a driving means for moving the valve member; a control means provided in the camshaft for controlling axial movement of the valve member according to operating conditions; and a control means provided in the cam member when the cam member is in the non-driving position. A valve drive device for an engine, comprising: a base circle portion that engages with the valve member.