JP2001227316A - Valve operation device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of part items demanded for a conventional device and to reduce manufacturing cost due to increase of working mandays and assembly mandays. SOLUTION: This valve action device is furnished with a locker arm 25 a head end part 25b of which makes contact with a pair of suction valves 21 and is driven by two cams 23 for low speed of a camshaft 22 and a free cam follower 26 to be driven by a cam 24 for high speed. An energizing means 28 provided on a lower end part of the free cam follower is constituted so as to be doubly used as pressurizing mechanism to energize in the engagement releasing direction with the free cam follower and a lost motion mechanism of the free cam follower as a plunger 34 to slide in a hole 33 for sliding motion makes constantly and elastically contact with an upper end part 27a of a lever member 27 by a coil spring 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating device for an engine valve such as an intake valve or an exhaust valve of an engine of an automobile or the like. The present invention relates to a valve operating device.

[0002]

2. Description of the Related Art Various types of valve actuating devices for engines of this type have been conventionally provided, one of which is known, for example, from Japanese Patent Application Laid-Open No. 5-171909. .

[0003] Referring to FIGS. 8 to 10, a single rocker arm 2 corresponding to two intake valves 1, 1 is provided for each cylinder, and the rocker arm 2 has a base end. The portion 2 a is swingably supported by a rocker shaft 6 provided in parallel with the camshaft 3, and the low-speed cams 4, 4 provided integrally with the camshaft 3, Is driven by the high-speed cam 5 disposed between the two.

[0004] Both ends 2 of the rocker arm 2 are provided.
b, 2b, a single free cam follower 8 swingably supported via a support shaft 7 fixed to the base end 2a.
A lost motion mechanism 9 for bringing the free cam follower 8 into contact with the high-speed cam 5;
Lever member 1 that functions or stops the function
0 is provided.

[0005] The free follower 8 has a cam follower portion 8b on its upper surface, which does not have a portion in contact with the intake valves 1 and 1 at its distal end portion 8a, and slides on the high-speed cam 5 on its upper surface.
The upper end portion 1 of the lever member 10 is provided below the cam follower portion 8b.
Step 11a with which the engaging part 0a engages, and the inclined part 11b connected thereto
Are formed.

The lost motion mechanism 9 includes a lost motion spring 9b housed in a concave portion 9a formed in a lower portion of the cam follower portion 8b, and the rocker arm base end portion 2a formed by a spring force of the lost motion spring 9b from the concave portion 9a. Spring retainer 9c elastically contacting the lower part of
And biases the free cam follower 8 upward.

The lever member 10 is bent in a substantially U-shape, and is swingably provided at a lower center portion of the rocker arm 2 via a pivot pin 12 as shown in FIGS. At the same time, the protrusion 10c on the upper side is pressed by the pressing mechanism 13 and is urged in a direction to release the engagement between the upper end 10a and the step 11a of the free cam follower 8. The pressing mechanism 13 presses the protrusion 10c via a spring retainer 13c by a spring force of a return spring 13b housed in a recess 13a formed in the rocker arm 2. The lower end portion 10b of the lever member 10 is pressed by the connection switching means constituted by the hydraulic drive unit 14, the hydraulic circuit 15, and the like according to the engine operation state, so that the upper end portion 10a and the step portion 11a are pressed.
To be engaged or released.

When the engine is running at a low speed, the engagement between the upper end portion 10a and the step portion 11a by the connection switching means is released, and the free cam follower 8 enters a free lost motion state by the lost motion mechanism 9. Therefore, the intake valves 1 and 1 are not transmitted from the high-speed cam 5 via the rocker arm 2 and are lifted according to the cam profiles of the low-speed cams 4 and 4, so that low valve lift characteristics are obtained. Therefore, the fuel efficiency can be improved by improving the combustion efficiency at the time of such low rotation.

On the other hand, when the engine is running at a high speed, the upper end portion 10a and the step portion 11a are engaged by the connection switching means, and the free cam follower 8 and the rocker arm 2 are connected. In addition, the lift force of the high-speed cam 5 is transmitted via the rocker arm 2 to achieve high valve lift characteristics. As a result, the intake charging efficiency is increased and a sufficient output can be secured.

[0010]

However, in the above-mentioned conventional apparatus, since the lost motion mechanism 9 and the pressing mechanism 13 are formed separately and independently, the number of parts is increased, and the machining operation and the assembling operation are performed. However, the efficiency of machining and assembling work of the entire apparatus is reduced, so that the cost is inevitably increased.

In addition, since the recess 13a is formed substantially horizontally in a state in which the valve operating device is mounted on the engine, the pressing mechanism 13 can reduce metal abrasion powder generated at a sliding portion during operation of the engine. Other foreign substances such as fibers and casting sand may be removed from the inner peripheral surface of the recess 13a and the spring retainer 1.
There is a risk that the intrusion into the minute gap between the outer peripheral surface of the spring retainer 3c and not only the smooth sliding of the spring retainer 13c but also sticking may occur.

[0012]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned conventional technical problems, and the invention according to claim 1 has a first cam and a second cam provided on a camshaft. A cam, a base end portion of which is swingably provided on a predetermined support portion, a distal end portion of which is in contact with an engine valve and is rockably supported by a predetermined support shaft and a rocker arm driven by the first cam. A free cam follower driven by the second cam, a lost motion mechanism for urging one end of the free cam follower in the second cam direction, and a position supported by the rocker arm to exert the function of the lost motion mechanism. A linking member capable of swinging to a position where the function of the lost motion mechanism is stopped, a pressing mechanism for urging the linking member in a first position direction, and each of the linking members according to an operation state of an engine. To position An engine valve actuating device provided with a link switching means for switching, wherein the free cam follower constantly contacts the lower end of the free cam follower with the one end of the link member to urge the free cam follower to the first position side, and An urging means for urging the other end of the member in the direction of disengaging the connection switching means is provided, and the urging means serves both as the lost motion mechanism and the pressing mechanism.

Therefore, according to the present invention, since the lost motion mechanism and the pressing mechanism are shared by one urging means, it is only necessary to manufacture this urging means alone. The number of points can be greatly reduced, and the number of processing steps and assembly steps can be reduced.

According to a second aspect of the present invention, the urging means includes a sliding hole formed at a substantially central position at a lower end of the free cam follower, and a tip end slidably held in the sliding hole. A part is constituted by a plunger abutting on an inner side surface of an upper end portion of the linking member, and a spring member elastically mounted in the sliding hole to bias the plunger toward the linking member.

By arranging the biasing means substantially at the center of the lower end of the free cam follower, an optimal arrangement for combining the lost motion mechanism and the pressing mechanism can be obtained. Therefore, both the lost motion mechanism and the pressing mechanism can be used. The function can be exhibited effectively.

The invention according to claim 3 is characterized in that the sliding hole is formed so as to be inclined downward toward the cylinder head of the engine.

Therefore, foreign matter such as metal abrasion powder generated during operation of the engine does not enter the sliding hole, and the plunger can always smoothly slide.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a valve operating device for an engine according to the present invention will be described below with reference to FIGS. This embodiment is also applied to an engine provided with two intake valves 21 per cylinder as in the prior art.

That is, as shown in FIGS. 1 and 2, the valve actuating device comprises two low-speed cams 23, which are first cams for each cylinder, mounted on a camshaft 22 disposed on a cylinder head S. , 23 and one high-speed cam 24 which is a second cam disposed between the low-speed cams 23, 23, and corresponding to the intake valves 21, 21 below the camshaft 22. A single rocker arm 25 is provided. At the center position of the rocker arm 25, a free cam follower 26 facing the high-speed cam 24 is swingably disposed, and a lever member as a linking member for appropriately linking the free cam follower 26 to the rocker arm 25. 27, and a biasing mechanism 28 that has both a lost motion function of bringing the free cam follower 26 into contact with the high-speed cam 24 and a function of pressing the lever member 27 in the uncoupling direction.

The low-speed cams 23, 23 and the high-speed cam 2
4 are formed in different shapes so as to satisfy the valve lift characteristics required when the engine is running at a low speed and at a high speed, and the high speed cam 24 is a low speed cam 23.
It is formed in a profile that makes the valve lift and the valve opening period larger than those of the above.

The rocker arm 25 is formed in a substantially bifurcated shape when viewed from the top, and the base end 25a is
Internal rocker shaft 20 provided in parallel with 2
, And each tip 25b,
Slippers 25, 25c are provided on the upper surfaces of the tip portions 25b, 25b, and the low-speed cams 23, 23 are in sliding contact with the stem top portions 21a, 21a of the intake valves 21, 21, respectively. Have been.

The free cam follower 26 is disposed in a space defined between both ends 25b, 25b of the rocker arm 25, and the base 26a is connected to the base end 25 of the rocker arm 25.
a is rotatably supported via a support shaft 29 press-fitted at its both ends, and the front end portion has no portion in contact with the intake valves 21, 21 and slides on the upper surface with the high-speed cam 24. The cam follower portion 26b is formed to protrude in an arc shape. Also, the cam follower portion 26b of the free cam follower 26
On the lower side, a step portion 30 with which the lever member 27 is engaged is formed. In addition, at the rear end of the base 26a,
A protrusion 26c is provided to abut on the edge of the notch groove 25d formed on the outer surface of the base end 25a of the rocker arm 25 to regulate the maximum elevation position of the free cam follower 26.

As shown in FIG. 1, the lever member 27 is formed in a substantially U-shape to be bent.
5 is pivotally supported by a pivot pin 31 having both ends fixed to the central lower wall through a substantially central insertion hole 27c. Further, the upper surface of the upper end portion 27a can be engaged with the lower surface of the step portion 30 while rotating, and the inner end surface of the lower end portion 27b bent substantially in an arc shape is linked to the link switching means 32. I have.

As shown in FIGS. 1, 6, and 7, the urging means 28 includes a cylindrical sliding hole 33 provided below the cam follower portion 26b of the free cam follower 26, and an inner portion of the sliding hole 33. Slidably provided at the distal end portion 34a.
Is engaged with the plunger 34 in contact with the inner surface of the upper end 27a of the lever member 27, and is engaged in the sliding hole 33 to press the plunger 34 against the inner surface of the upper end 27a clockwise in the drawing to engage the lever member 27. And a coil spring 35 that is a spring member that urges in the release direction. The sliding hole 33 is formed so that the opening end 33a is directed downward with respect to the cylinder head S when the valve operating device is disposed and fixed on, for example, a horizontal cylinder head S of an in-line type engine. The whole is formed in an inclined shape.

The link switching means 32 includes a hydraulic drive unit 36 linked to the lower end 27b of the lever member 27.
And a hydraulic circuit 37 that supplies and discharges hydraulic pressure to the hydraulic drive unit 36. The hydraulic drive unit 36 is slidably provided in a cylinder 38 formed at the lower wall end of the rocker arm base end 25a, and has a front end surface abutting on the lever member lower end 27b. Working piston 39
And a hydraulic chamber 4 formed on the rear end side of the working piston 39.
0. The hydraulic circuit 37 is formed inside the rocker shaft 20 and the inside of the base end portion 27a, and communicates with the hydraulic chamber 40 through a hydraulic passage 41, and the hydraulic passage 41 is connected to the hydraulic passage 41 via an oil main gallery (not shown). And an electromagnetic switching valve provided downstream of the oil pump to switch between the hydraulic passage 41 and the drain passage according to a control signal from a controller. The controller inputs an engine rotation signal, a cooling water temperature signal, a lubricating oil temperature signal, and a throttle valve opening signal, and outputs a control signal to the electromagnetic switching valve based on these detected values.

Therefore, according to this embodiment, when the engine is running at a low speed, the electromagnetic switching valve communicates the oil pump with the drain passage by the control signal from the controller, and the supply of the hydraulic pressure to the hydraulic chamber 40 is cut off. . For this reason,
The working piston 39 does not press the lower end 27b of the lever member 27. Therefore, although the free cam follower 26 is swung by the lift of the high-speed cam 24, the lever member 27 releases the engagement between the upper end portion 27 a and the step portion 30 by the spring force of the coil spring 35 of the urging means 28. And is held in the first position shown in FIGS. 1 and 6,
The lost motion function of the free cam follower 26 by the urging means 28 is exerted, and the lift transmission of the high-speed cam 24 to the rocker arm 25 is not performed.

Therefore, the rocker arm 25 swings through the rocker shaft 20 according to the profile of the low-speed cams 23, 23. Thereby, each intake valve 21,
Reference numeral 21 performs opening / closing operation based on low valve lift characteristics.

On the other hand, when the engine is rotating at a high speed, the electromagnetic switching valve is switched by the controller, and the hydraulic pressure pumped from the oil pump flows from the hydraulic passage 41 to the hydraulic chamber 40.
And the working piston 39 is advanced with the increase of the pressure in the hydraulic chamber 40. Therefore, the working piston 3
9 holds the lever member 27 in the second position shown in FIG. 7 by rotating the lever member 27 counterclockwise in FIG. 1 against the spring force of the coil spring 35 of the urging means 28. As a result, the upper end portion 27a of the lever member 27 engages with the step portion 30 to integrally connect the rocker arm 25 and the free cam follower 26. For this reason, the rocker arm 25 is
Swing, that is, the tip portions 25b, 25b of the rocker arm 25
3, the abutment is avoided and the free cam follower 26 swings according to the profile of the high-speed cam 24 as the free cam follower 26 swings. For this reason, the intake valves 21, 21
Opens and closes according to high valve lift characteristics.

As described above, according to the present embodiment, the biasing means 28 has both the lost motion function of the free cam follower 26 and the function of pressing the lever member 27 in the disengagement direction, so that both functions are effectively exhibited. Can be. Therefore, since only the single urging means 28 needs to be provided, the number of parts can be significantly reduced as compared with the related art, and the number of processing steps and the number of assembly steps can be reduced, and the manufacturing cost can be reduced. Can be achieved.

In addition, since the biasing means 28 is provided at the central position below the cam follower portion 26b of the free cam follower 26, the biasing means 28 is located at an optimum position for exerting the lost motion function and the pressing function. It is possible to demonstrate.

Further, since the sliding hole 33 is formed so as to be inclined downward with respect to the horizontal cylinder head S of the engine, foreign matter such as metal abrasion powder generated during operation of the engine enters the sliding hole 33. Can be avoided. As a result,
The plunger 34 always has a smooth sliding action, and the urging means 28 can maintain a good operating state of both functions.

The present invention is not limited to the configuration of the above embodiment. For example, it is possible to use both the coil spring 35 and the oil pressure as the urging means 28. Also,
The first cam may be a high-speed cam and the second cam may be a low-speed cam. Further, the structures of the rocker arm 25 and the free cam follower 26 can be appropriately changed according to the size and specifications of the engine. .

[0033]

As is apparent from the above description, claim 1
According to the invention described in (1), since the lost motion mechanism and the pressing mechanism are shared by one urging means, it is only necessary to provide this urging means. It is possible to reduce the number of processing steps and assembling steps. As a result, the manufacturing cost of the apparatus can be significantly reduced.

According to the second aspect of the present invention, by arranging the urging means substantially at the center of the lower end of the free cam follower 26, an optimum arrangement for combining the lost motion mechanism and the pressing mechanism is obtained. Therefore, it is possible to effectively exhibit both functions of the lost motion mechanism and the pressing mechanism.

According to the third aspect of the present invention, foreign matter such as metal abrasion powder generated during operation of the engine does not enter the sliding holes, and the plunger can always smoothly slide. It is possible to maintain a favorable operating state of the urging means exhibiting both functions.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along the line AA of FIG. 2, showing an embodiment of a valve operating device of an engine according to the present invention.

FIG. 2 is a plan view of a main part of the embodiment.

FIG. 3 is a view shown by an arrow B in FIG. 2;

FIG. 4 is a view taken along the line CC of FIG. 2;

FIG. 5 is a sectional view taken along line DD of FIG. 4;

FIG. 6 is an operation explanatory view of the embodiment.

FIG. 7 is an operation explanatory view of the embodiment.

FIG. 8 is a main part plan view showing a conventional valve operating device.

FIG. 9 is a sectional view taken along line EE of FIG. 8;

FIG. 10 is a sectional view taken along line FF of FIG. 8;

[Explanation of symbols]

 Reference Signs List 21 intake valve 22 camshaft 23 low-speed cam 24 high-speed cam 25 rocker arm 25b distal end 26 free cam follower 26b cam follower 27 lever member 27a upper end 27b lower end 28 urging means Reference Signs List 30 step portion 31 pivot pin 32 linkage switching means 33 sliding hole 34 plunger 35 coil spring

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) 3G016 AA06 AA19 BA03 BA18 BB12 BB16 BB21 BB25 BB26 CA21 CA25 CA28 CA29 CA33 DA08 FA38 GA01 3G018 AB04 AB12 AB16 BA13 CA19 CB03 CB05 CB06 DA10 DA13 DA14 DA15 DA18 DA19 DA11 GA17 GA18

Claims (3)

[Claims] 1. A first cam and a second cam provided on a camshaft, and a base end portion is swingably provided on a predetermined support portion, and a front end portion abuts on an engine valve, and is provided by the first cam. A driven rocker arm, a free cam follower swingably supported by a predetermined support shaft and driven by the second cam, and a lost motion mechanism for urging one end of the free cam follower in the second cam direction. A linking member supported by the rocker arm and capable of swinging between a first position at which the function of the lost motion mechanism is exercised and a second position at which the function of the lost motion mechanism is stopped; A valve operating device for an engine, comprising: a pressing mechanism for urging the link member; and link switching means for switching the link member between the first position and the second position in accordance with an operation state of the engine. The distal end of the free cam follower is always in elastic contact with one end of the linking member to urge the lower end of the free cam follower toward the first position, and urges the other end of the linking member in the direction of disengaging the connection switching means. A valve operating device for an engine, wherein the urging unit serves as both the lost motion mechanism and the pressing mechanism. 2. The urging means comprises: a sliding hole formed substantially at the center of a lower end of the free cam follower; 2. The valve operating device for an engine according to claim 1, further comprising: a plunger abutting on a side surface; and a spring member elastically mounted in the sliding hole and biasing the plunger in a direction of a linking member. 3. The valve operating device for an engine according to claim 2, wherein the sliding hole is formed so as to be inclined downward toward the cylinder head of the engine.