JPH066164Y2 - Intake / exhaust valve opening / closing timing control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a device for controlling the opening / closing timing of intake / exhaust valves of an internal combustion engine, and more particularly to improving maintainability.

<Prior Art> An example of a conventional device of this type is shown in FIG. 2 (US Pat. No. 4,421,074, class 123/90.
15 Published December 20, 1983, "Motor Fan," December 1982 issue 2
See pages 22-224, etc.).

To explain the outline of this, a cam shaft 1 having a cam (not shown) for opening and closing an intake valve or an exhaust valve of an engine, or both of them (hereinafter referred to as intake and exhaust valves) is supported by a cylinder head 2 and one end thereof is provided. The extension shaft 3 is fixed by screwing. A sleeve 5 is rotatably supported by the outer circumference of a stopper 4 press-fitted and fixed to the tip of the extension shaft 3 and the outer circumference of a base end portion of the extension shaft 3, and a pulley 6 fitted on the outer circumference of the sleeve 5 is attached to the sleeve 5. It is non-rotatably fixed to the sleeve 5 between the protrusion 5a formed on the above and a nut 7 screwed to the tip of the sleeve 5.

The pulley 6 has external teeth and is rotated in conjunction with the crankshaft via a toothed belt or the like engaged with the external teeth.

Further, the outer teeth 8a are engaged with the inner teeth 5b formed on the sleeve 5, and the inner teeth 8b are formed on the extension shaft 3 and the outer teeth 3 are formed on the extension shaft 3.
A ring piston 8 that engages with a and is free to slide axially on the inner peripheral surface of the sleeve 5 is provided.

Here, at least one set of the outer teeth 8a and the inner teeth 5b or the outer teeth 3a and the inner teeth 8b meshes in a spiral shape, and when the ring piston 8 moves in the axial direction by this, the camshaft 1 moves to the sleeve 5 and It is adapted to rotate relative to the pulley 6 about its axis.

The ring piston 8 is biased leftward in the drawing by a spring 9 that is fitted between the ring piston 8 and the extension shaft 3.

On the other hand, the pressurized engine oil passes from the oil passage 2a formed in the cylinder head 2 to the annular groove 1a formed in the camshaft 1, the oil passage 1b, and the oil hole 3 formed in the extension shaft 3.
It is introduced into the pressure receiving surface of the ring piston 8 opposite to the spring 9 through the gap between the inner tooth 8b and the outer tooth 3a through b.

Further, the flow control valve 10 fitted into the end portions of the stopper 4 and the cam shaft 1 is normally located at the left end position in the figure by the spring 11, and is formed by overlapping the extension shaft 3 and the cam shaft 1 at this position. Oil flows out from the oil holes 3c, 1c through the oil outflow hole 10a formed in the flow control valve 10, and therefore the ring piston 8 is at the left end position biased by the spring 9.

From this state, when the rod 12a of the electromagnetic actuator 12 which engages with the left end surface of the flow control valve 10 in the drawing extends to the right in the drawing, the flow control valve 10 also moves to the right and the oil holes 3c and 1c.
Is cut off.

As a result, the oil pressure applied to the pressure receiving surface of the ring piston 8 rises, and the ring piston 8 moves rightward in the figure against the spring 9, so that the camshaft 1 moves relative to the pulley 6 and thus the crankshaft as described above. Rotate relative to each other, thereby changing the opening / closing timing of the intake / exhaust valve.

<Problems to be Solved by the Invention> However, in such a conventional device, the flow control valve is
When the oil flows out from 10, the scattered oil adheres to the rubber portion of the belt that engages with the outer teeth of the pulley 6 and deteriorates the rubber portion, and eventually the belt is damaged and absorbed.
There is a problem in that the opening / closing timing of the exhaust valve may be significantly different, and in the worst case, the intake / exhaust valve and the piston may interfere with each other to damage the engine.

The present invention has been made in view of such conventional problems, and prevents deterioration of the driving force transmission mechanism due to a hydraulic medium such as engine oil flowing out from the flow control valve.
An object of the present invention is to provide an intake / exhaust valve opening / closing timing control device for an internal combustion engine, which is capable of preventing the opening / closing timing of the intake / exhaust valve from being damaged and the engine from being damaged.

<Means for Solving Problems> Therefore, according to the present invention, a drive wheel for driving the camshaft and a hydraulic actuator for rotating the drive wheel relative to the camshaft are arranged on one end side of the camshaft. A flow control valve for controlling the inflow or outflow of the hydraulic medium of the hydraulic actuator is arranged on the other end side, and a hydraulic medium passage connecting the hydraulic actuator and the flow control valve is provided inside the camshaft, An electromagnetic actuator for driving the flow control valve is provided at an end portion in the longitudinal direction of the engine facing the flow control valve.

<Operation> With this configuration, even if the hydraulic medium flows out from the flow control valve in order to rotate the drive wheel relative to the camshaft, it is separated from the drive wheel, and therefore the drive wheel is driven. Stable intake / exhaust valve opening / closing timing control performance can be maintained without deteriorating the force transmission mechanism. Further, since the flow control valve is separated from the hydraulic actuator having a complicated structure and has a small structure separate from the electromagnetic actuator, it can be easily assembled on the other end side of the camshaft.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1 showing an embodiment, an extension shaft 22 is screwed to one end of a cam shaft 21, and a sleeve 24 is fitted and inserted into a stopper 23 and the extension shaft 22 that are press-fitted into the end of the extension shaft 22. . An oil seal 26 is attached between the sleeve 24 and the cylinder head 25. The protrusion 24a formed on the outer periphery of the sleeve 24 and the nut 27 screwed to the sleeve 24
A pulley 28 serving as a drive wheel for driving the camshaft is fixed between and, and external teeth 28a formed on the pulley 28 are
The inner teeth 29a of the toothed belt 29 as a winding member that transmits the rotational force of the crankshaft are engaged.

Between the stopper 23 and the extension shaft 22, the inner teeth 24b formed on the sleeve 24 and the outer teeth 22a formed on the extension shaft 22 are engaged with the outer teeth 30a and the inner teeth 30b, respectively. A ring piston 30 which is free to move and a spring 31 which biases the ring piston 30 leftward in the drawing are provided. The internal teeth 24b and the external teeth 30
At least one set of a, the outer teeth 22a and the inner teeth 30b is formed in a spiral, and the camshaft 21 can be relatively rotated with respect to the pulley 28 by the movement of the ring piston 30, as in the conventional case. A cover 32 covering the outside of the pulley 28, the toothed belt 29, etc. is connected to a rocker cover 33.

A flow control valve 34 is provided at the opposite end of the camshaft 21. That is, in the hole 21a formed in the axial direction at the end of the camshaft 21 opposite to the end where the pulley 28 is attached,
A valve housing 34b, in which the outer peripheral wall of the outer end portion is fixed to the hole 21a by press fitting or screwing, is mounted. The valve housing 34b has an inner end wall closed, an inner outer peripheral wall having an annular gap between the inner peripheral wall and the hole 21a, and a valve hole 34a penetrating the inner outer peripheral wall. ing. Further, a hollow sleeve-shaped valve body 34d having one end opened and the other end closed is mounted on the valve housing 34b. That is, the valve-side end portion of the valve body 34d is fitted and inserted so that the opening-side end portion thereof slides in the valve housing 34b in the axial direction to open and close the valve hole 34a, and the valve-side end portion protrudes to the outside of the valve housing 34b. An outflow hole 34c is formed in the. Further, a spring 34e is installed between the valve housing 34b and the valve body 34d to urge the valve body 34d outward. The valve housing 34b, the valve element 34d and the spring 34e constitute a flow control valve 34.

An electromagnetic actuator 35 is attached to an end wall of a rocker cover 33 located at an end portion in the longitudinal direction of the engine so as to face the flow control valve 34, and an output rod 35 of the electromagnetic actuator 35 is attached.
a engages with the end face of the valve element 34d of the flow control valve 34,
d is driven.

Further, an oil passage 21b connecting the left end surface of the cam shaft 21 in the drawing and the hole 21a, and an annular groove 21 formed in a portion of the oil passage 21b facing the cam shaft bearing hole of the cylinder head 25.
An oil passage 21d connecting to c is formed.

An oil passage 25a is formed in the camshaft bearing portion of the cylinder head 25 to guide the engine oil as a hydraulic medium pressure-fed from an oil pump (hydraulic medium supply source) (not shown) to the annular groove 21c.

These oil passages 25a, 21d, 21b, annular groove 21c and hole 21a
Constitute a hydraulic medium passage.

Further, an oil passage 22b is formed in the extension shaft 22, and the oil passage 21b extends from the oil passage 22b to the outer teeth 22a and the inner teeth 30.
Oil is guided to the left end surface of the ring piston 30 in the figure through a gap with b. Therefore, the sleeve 24, the extension shaft 22,
The stopper 23, the ring piston 30, and the spring 31 constitute a hydraulic actuator for rotating the camshaft 21 relative to the pulley (driving wheel) 28, and a hydraulic chamber is formed in the left side portion of the ring piston 30 in the drawing.

Next, the operation will be described.

When the electromagnetic actuator 35 is not energized, the rod 35a is in the retracted position as shown in the figure, and the valve element 34d of the flow control valve 34 is in the right end position by the spring 34e, so that the valve hole
34a is open.

In this state, the oil that has flowed from the oil passage 25a of the cylinder head 25 into the annular groove 21c of the camshaft 21 and the oil passages 21d and 21b passes through the valve hole 34a of the flow control valve 34 from the hole 21a and the outflow hole 34c. From the outside.

Therefore, the pressure of the oil flowing from the oil passage 21b into the hydraulic chamber on the left end face side of the ring piston 30 through the oil passage 22b and the gap between the outer teeth 22a and the inner teeth 30b is small, and the ring piston 30 is attached by the spring 31. The intake / exhaust valve opening / closing timing is controlled according to the relative rotational position between the cam shaft 21 and the pulley 28 located at the left end position due to the force.

Then, at this time, even if the oil flowing out from the oil outflow hole 34c is scattered around, the toothed belt 29 that drives the pulley 28 is provided at the end portion on the opposite side of the cam shaft 21, so that the oil is toothed belt 29. Can be prevented from adhering to. As a result, it is possible to prevent deterioration of the rubber portion of the toothed belt 29 due to oil, so that it is possible to prevent deviation of the opening / closing timing of the intake / exhaust valve and eventually damage due to interference between the intake / exhaust valve and the piston.

On the other hand, when the predetermined operating condition is reached, the electromagnetic actuator 35
Is energized, the rod 35a extends, the valve body 34d is pressed against the spring 34e, and the valve hole 34a is closed.

Therefore, the pressure of the oil guided to the rear surface of the ring piston 30 rises and moves to the right in the figure against the spring 31, so that the cam shaft 21 relatively rotates with respect to the pulley 28 by a predetermined angle, and intake / exhaust is performed. The opening / closing timing of the valve is shifted by a predetermined crank angle, and the opening / closing timing is controlled to match the operating condition.

Further, since the flow rate control valve 34 is separated from the hydraulic actuator having a complicated structure, and the electromagnetic actuator 35 is a separate structure and small in size, it can be easily assembled on the other end side of the camshaft 21. It also has excellent maintainability. Normally, the transmission case is arranged at the end portion in the longitudinal direction of the engine on the side opposite to the camshaft drive side, and the upper portion thereof is an extra space. In that case, assembly and maintenance are further advantageous.

<Advantages of the Invention> As described above, according to the present invention, the drive wheel for driving the camshaft and the flow control valve are arranged separately at both ends of the camshaft, so that the flow out of the flow control valve. It is possible to prevent the generated hydraulic medium from adhering to a winding member or the like that transmits the rotational force of the crankshaft to the drive wheel, and to prevent deterioration of the winding member.
The opening / closing timing of the intake / exhaust valve due to damage can be prevented, and damage due to interference between the intake / exhaust valve and the piston can be prevented. In addition, the flow control valve is separated from the hydraulic actuator with a complicated structure, and because it is a small structure separate from the electromagnetic actuator, it can be easily assembled on the other end side of the camshaft, and it is excellent in maintainability. It is a thing.

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of the structure of an embodiment of the present invention, and FIG. 2 is a sectional view showing an essential part of a conventional example. 21 ... Camshaft, 21a ... hole, 21b, 21d ... oil passage, 21c ... annular groove, 22 ... extension shaft, 23 ... stopper,
24 ...... sleeve, 25a ... oil passage, 28 ... pulley, 29 ...
… Toothed belt, 30 …… Ring piston, 31 …… Spring, 34 …… Flow control valve, 35 …… Electromagnetic actuator

Continuation of the front page (56) References Microfilm (JP, U) Actual Application Sho 54 Microfilm (JP, U) taken from the contents of the specification and drawings attached to the application of No. 4901 (Japanese Utility Model Application No. 55-104704)

Claims (1)

[Scope of utility model registration request] 1. A camshaft having a cam for opening and closing an intake / exhaust valve of an internal combustion engine, and a drive wheel interlocking with a crankshaft via a wrapping member for rotationally driving the camshaft with respect to the camshaft. A hydraulic actuator that rotatably rotates a predetermined angle and that rotates the camshaft relative to the drive wheel in response to the pressure of the hydraulic medium introduced into the hydraulic chamber, and the hydraulic chamber of the hydraulic actuator. By closing the hydraulic medium passage connecting to the pressure medium supply source to increase the hydraulic pressure in the hydraulic chamber, or by letting out the hydraulic medium from the hydraulic medium passage to the outside, the hydraulic pressure in the hydraulic chamber is reduced. In an intake / exhaust valve opening / closing timing control device for an internal combustion engine, which comprises a flow rate control valve for controlling a relative rotational position of a camshaft with respect to a drive wheel, a drive wheel and a hydraulic actuator are provided on one end side of the camshaft. And a flow control valve on the other end side of the camshaft, and a hydraulic medium passage connecting the hydraulic pressure chamber of the hydraulic actuator and the flow control valve is provided inside the camshaft. Facing the flow control valve,
An intake / exhaust valve opening / closing timing control device for an internal combustion engine, characterized in that an electromagnetic actuator for driving the flow control valve is provided at an end portion in the longitudinal direction of the engine.