JPH11218006A - Locker arm structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure sufficient rigidity for torsion and a disadvantage in strength by providing a cavity part on a valve side adjacent wall surface on the side which is adjacent to a boss part center line on the side of a tip of a valve side arm part so as to move the center of gravity on the side of the tip of the valve side arm part to the side of a valve side distance wall surface. SOLUTION: In the structure of a locker arm 60, a cavity part 102 is provided on a valve side adjacent wall surface 100 on the side of a tip 92 of a valve side arm part 84 so as to move the center of gravity on the side of the tip 92 of the valve side arm part 84 to the side of a valve side distance wall surface 98. As a result, a valve side arm part center line L3 can be displaced to the side of the valve side distance wall surface 98 and the valve side arm part center line L3 can be made adjacent to a screw hole 96 or be superposed on the hole 96. Load from the valve side can be received in the vicinity of the valve side arm part center line L3 or on the valve side arm part center line L3, torsion can be reduced, an advantage in strength can be obtained and the locker arm 60 can be made light in weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rocker arm structure, and more particularly, to a rocker arm structure capable of reducing torsion, improving strength, and reducing weight.

[0002]

2. Description of the Related Art In an engine, a valve mechanism is provided to drive intake and exhaust valves of a combustion chamber. Some valve operating mechanisms drive a valve by swinging a rocker arm by a camshaft. Rocker arms include a seesaw type and a swing type.

FIGS. 6 to 9 show the structure of such a rocker arm. In the figure, 202
Is a rocker shaft, 204 is a seesaw type rocker arm, 206 is a boss, 208 is a cam side arm, 210
Denotes a valve side arm. The rocker arm 204
A cylindrical boss portion 206 is pivotally supported by the rocker shaft 202, and the boss portion 206 has a base end 212.2.
A cam-side arm portion 208 and a valve-side arm portion 210 are provided which are connected to each other on the 14th side and extend in a direction intersecting the boss portion axis L1 of the boss portion 206 and extending away from each other at the tips 216 and 218 side. The boss portion 206 is provided with a shaft hole 220 through which the rocker shaft 202 is inserted.

As shown in FIG. 6, the cam-side arm portion 208 and the valve-side arm portion 210 pass through the respective centers of gravity of the thickness in the direction of the boss portion axis L1 in plan view, and
It has a cam-side arm center line L2 and a valve-side arm center line L3 which are respectively drawn from the 14 side toward the tips 216 and 218. The boss portion 206 has a boss portion center line L4 which passes through the center C in the direction of the boss portion axis L1 and is orthogonal to the boss portion axis L1 in a plan view.

[0005] The cam-side arm portion 208 and the valve-side arm portion 210 are connected to the center line L2 of the cam-side arm portion in plan view.
In addition, the center line L3 of the valve-side arm portion is different from the center line L4 of the boss portion 206 in plan view by each tip 216.
The bases 212 and 214 are connected to the boss 206 so as to be on the respective sides of the 218 on the boss axis L1 direction.

As a result, the rocker arm 204 is provided with the boss portion 20 in order to avoid interference with obstacles such as a spark plug and a boss portion (not shown) provided on the cylinder head.
6 and the cam-side arm center line L2 and the valve-side arm center line L2 with respect to the boss center line L4 in plan view.
3 are connected so as to cross diagonally.

The cam-side arm portion 208 has a cam sliding contact portion 222 on the tip 216 side. The cam sliding contact part 222 is
It is slid on a cam of a cam shaft (not shown). The valve side arm section 210 has a screw hole 224 on the tip 218 side. An adjusting screw 226 that is in contact with a valve stem of a valve (not shown) is screwed into the screwing hole 224 and fixed by an adjusting nut 228.

As a rocker arm of such a valve operating mechanism, there is one disclosed in Japanese Utility Model Publication No. 8-9362. The rocker arm disclosed in this publication is provided with two exhaust side rocker arms that are swingably supported on a rocker arm shaft with an ignition plug insertion tube interposed therebetween.
The valve-side arm portion of the exhaust-side rocker arm is obliquely connected to the boss portion so as to extend around the spark plug insertion tube, thereby avoiding interference of the ignition plug insertion tube.

[0009]

By the way, FIG.
The rocker arm 204 shown in FIG. 9 is provided with a screw hole 224 for an adjusting screw 226 to be in contact with the valve stem of the valve on the tip 218 side of the valve arm 210. The rocker arm 204 receives a load from the valve side by the adjusting screw 226 screwed into the screw hole 224.

However, as shown in FIG. 6, the screw hole 224 does not lie on the valve-side arm center line L3 on the distal end 218 side of the valve-side arm portion 210 but on the valve-side arm center line L3. It is provided so as to be deviated toward the valve-side separating wall surface 230 on the side away from the center line L4.

Therefore, the rocker arm 204 receives a load from the valve side to the screw hole 224 at a position shifted from the center line L3 of the valve-side arm portion of the valve-side arm portion 210. There is a disadvantage that strength is disadvantageous.

Further, if the rocker arm 204 has a structure that ensures sufficient rigidity against such torsion and disadvantageous strength, there is a disadvantage that the weight increases.

[0013]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a cylindrical boss portion which is rotatably supported by a rocker shaft, and the boss portion is connected to the base end side. A cam-side arm portion and a valve-side arm portion each extending in a direction intersecting the boss portion axis direction of the boss portion and extending away from each other, and the cam-side arm portion and the valve-side arm portion are bosses. The center line of the cam-side arm and the center line of the valve-side arm drawn through the respective centers of gravity in the axial direction from the base end to the respective distal ends are centered in the boss axial direction of the boss. Each base end side is connected to the boss portion so as to be present on each side of the boss portion axial direction at each distal end side with respect to the boss portion center line drawn in a direction orthogonal to the boss portion axis line through the boss portion. The cam side arm A cam slide contact portion that slides on a cam of a camshaft is provided on a distal end side of the portion, and a screw hole of an adjusting screw that is in contact with a valve stem of a valve is provided on a distal end side of the valve side arm portion. In a rocker arm provided so as to be deviated toward the valve-side separating wall surface on the side away from the boss center line with respect to the center line of the boss, the center of gravity of the distal end side of the valve-side arm portion is moved toward the valve-side separating wall surface. A recess is provided on the valve-side proximity wall surface on the side close to the center line of the boss on the distal end side of the valve-side arm portion.

The rocker arm has a cam-side lightening portion and a cam-side lightening portion on a cam-side proximate wall surface on a side close to a center line of a boss portion of the cam-side arm portion and a cam-side protruding wall surface on a separating side. The valve-side arm portion is connected to at least the valve-side proximity wall surface of the valve-side proximity wall surface on the side close to the boss center line and the valve-side separation wall surface of the valve-side separation wall surface that is continuous with the cam-side proximity lightening portion. A valve-side proximity lightening portion is provided.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rocker arm structure according to the present invention is arranged such that a center of gravity on the distal end side of a valve side arm is moved toward a valve side separating wall side, and is close to a center line of a boss on a distal end side of a valve side arm. By providing a concave portion on the valve-side proximity wall surface on the valve side, the valve-side arm portion center line can be displaced toward the valve-side separated wall surface side, and the valve-side arm portion center line approaches or overlaps with the screw hole. be able to.

Further, the rocker arm structure of the present invention comprises:
The valve-side arm portion is provided with a cam-side lightening portion and a cam-side lightening portion on a cam-side proximity wall surface of the cam-side arm portion adjacent to the boss center line and a cam-side separation wall surface of the cam-side separation portion, respectively. The valve-side proximity lightening portion that is continuous with the cam-side proximity lightening portion is provided on at least the valve-side proximity wall surface of the valve-side proximity wall surface on the side close to the boss portion center line and the valve-side separation wall surface on the separation side. Thereby, the valve side arm portion can be reinforced.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show an embodiment of the present invention. In FIG. 5, 2 is an engine, 4 is a cylinder block, 6 is a cylinder head, 8 is a head cover, 10 is a piston, and 12 is a combustion chamber. The engine 2 has an intake port 14 communicating with the cylinder head 6 and the combustion chamber 12.
And an exhaust port 16, and an intake valve 22 and an exhaust valve 24 for opening and closing the intake port 18 and the exhaust port 20 of the intake port 14 and the exhaust port 16, respectively.

The intake valve 22 and the exhaust valve 24 are provided at one end of an intake valve stem 26 and an exhaust valve stem 28 with an intake valve head 30 and an exhaust valve head 32 which are brought into contact with and separated from the intake port 18 and the exhaust port 20, respectively. On the end side, an intake stem contact portion 34 and an exhaust valve contact portion 36 driven by an intake rocker arm 60 and an exhaust rocker arm 62 described later are provided, respectively.

The intake valve 22 and the exhaust valve 24 hold the intake valve stem 26 and the exhaust valve stem 28 in the cylinder head 6 so as to be axially movable by an intake stem guide 38 and an exhaust stem guide 40. Also,
The intake valve 22 and the exhaust valve 24 are provided between the cylinder retainer 6 and the intake retainer 42 and the exhaust retainer 44 fixed to the intake valve stem 26 and the exhaust valve stem 28 in a direction to close the intake port 18 and the exhaust port 20. An intake valve spring 46 and an exhaust valve spring 48 for applying an urging force are provided respectively.

The engine 2 has a valve operating mechanism 52 for driving the intake valve 22 and the exhaust valve 24 in a valve operating chamber 50 formed by the cylinder head 6 and the head cover 8. The valve operating mechanism 52 supports a camshaft 54 driven in synchronization with a crankshaft (not shown) on the cylinder head 6. The camshaft 54 is provided with an intake cam 56 and an exhaust cam 58.

The valve mechanism 52 includes a seesaw-type intake rocker arm 60 and a swing-type exhaust rocker arm 62 that are oscillated by an intake cam 56 and an exhaust cam 58 of a camshaft 54.

The intake rocker arm 60 has an intake boss portion 6 which is supported by an intake rocker shaft 64 at an intermediate position.
6 is provided, an intake cam sliding contact portion 68 is provided on one end side of the intake cam 56 for sliding contact with the intake cam 56, and an adjusting screw 70 is provided on the other end side of the adjusting screw 70 in contact with the intake stem contacting portion 34 of the intake valve stem 26. 72 fixedly provided.

The exhaust rocker arm 62 has an exhaust arm-side pivot 7 supported at one end by a head-side pivot 74.
6 and an exhaust cam sliding contact portion 78 to which the exhaust cam 58 slides is provided on one surface of the other end, and is in contact with the exhaust stem contact portion 36 of the exhaust valve stem 28 on the other surface of the other end. An exhaust arm side contact portion 80 is provided.

Thus, the valve operating mechanism 52 is connected to the intake cam 5
6 swings the seesaw type intake rocker arm 60 to drive the intake valve 22, and swings the swing type exhaust rocker arm 62 by the exhaust cam 58 to drive the exhaust valve 24.

Although the valve operating mechanism 52 of this embodiment has a seesaw type intake rocker arm 60 and a swing type exhaust rocker arm 62, both the intake rocker arm 60 and the exhaust rocker arm 62 are of the seesaw type. There are also some (see Jitsuhei 8-9362).

The rocker arm structure of the present invention relates to a seesaw type rocker arm regardless of the intake side or the exhaust side. Therefore, in the following embodiments, the seesaw-type intake rocker arm 60 will be referred to and simply described as the rocker arm 60.

As shown in FIGS. 1 to 4, the rocker arm 60 is provided with a cylindrical boss 66 that is supported by a rocker shaft 64, and the boss 66 has a cam-side arm 82.
And a valve-side arm 84. The cam-side arm portion 82 and the valve-side arm portion 84 are provided so that the base ends 86 and 88 are connected to the boss portion 66, and the tip ends 90 and 92 respectively intersect with the boss portion axis L1 of the boss portion 66. It is provided to extend in the direction of separation. The boss 66 is provided with a shaft hole 94 through which the rocker shaft 64 is inserted.

As shown in FIG. 3, the cam-side arm portion 82 and the valve-side arm portion 84 pass through each center of gravity in the direction of the boss portion axis L1 in plan view, and extend from the base ends 86 and 88 to the distal ends. It has a cam-side arm center line L2 and a valve-side arm center line L3 that are respectively drawn in directions toward the 90 and 92 sides. The boss portion 66 passes through the center C in the direction of the boss portion axis L1 in plan view, and passes through the boss portion axis L1.
And a boss center line L4 drawn in a direction perpendicular to the boss portion.

The cam-side arm portion 82 and the valve-side arm portion 84 are arranged such that the center line L2 of the cam-side arm portion and the center line L3 of the valve-side arm portion in plan view are different from the center line L4 of the boss portion 66 in plan view. So that each tip 90/92 is located on each side of the boss portion axis L1 direction,
The base ends 86 and 88 are connected to the boss portion 66, respectively.

Thus, the rocker arm 60 is provided with a boss 66 for avoiding interference with an obstacle such as a spark plug or a boss (not shown) provided on the cylinder head 6.
The cam side arm portion 82 and the valve side arm portion 84
Are provided such that the cam-side arm center line L2 and the valve-side arm center line L3 obliquely intersect with the boss center line L4 in plan view.

A cam sliding portion 68 which is in sliding contact with the cam 56 of the cam shaft 54 is provided on the tip end 90 side of the cam side arm portion 82.
Is provided. A screw hole 96 is provided on the distal end 92 side of the valve side arm portion 84. An adjusting screw 70 that is in contact with the stem contact portion 34 of the valve stem 26 of the valve 22 is screwed into the screw hole 96. The adjusting screw 70 is fixedly provided by an adjusting nut 72.

A screw hole 96 provided on the tip end 92 side of the valve side arm portion 84 is provided on the valve side separation wall surface 98 side of the valve side arm portion center line L3 and on the side away from the boss portion center line L4. It is provided so as to be deviated.

The rocker arm 60 moves the center of gravity of the distal end 92 of the valve-side arm 84 toward the valve-side separating wall 98 side.
The concave portion 102 is provided on the valve-side proximity wall surface 100 on the side close to the center boss portion center line L4. As a result, as shown in FIG.
The solid portion 10 is provided on the valve-side separating wall 98 side of the tip 92 side of the nozzle 4.
4 and a screw hole 96 is provided in the solid portion 104.

Further, this rocker arm 60 is similar to that shown in FIG.
As shown in FIGS. 3 and 4, the cam-side proximity wall surface 106 on the side close to the boss center line L4 of the cam-side arm portion 82 and the cam-side separation wall surface 108 on the side away from the cam-side arm portion 82, respectively. And a cam-side separated lightening portion 112 is provided.

Further, the rocker arm 60 has a valve-side proximity wall surface 100 on the side close to the boss center line L4 of the valve-side arm portion 84 and a valve-side separation wall surface 9 on the separation side.
8, at least on the valve side proximity wall surface 100, the valve side proximity thickness reduction portion 114 which is continuous with the cam side proximity thickness reduction portion 110.
Is provided. The valve-side proximity lightening portion 114 is provided continuously with the concave portion 102 provided on the valve-side proximity wall surface 100.

As described above, the rocker arm 60 has a structure in which the center of gravity of the distal end 92 of the valve-side arm 84 is moved toward the valve-side separating wall 98 so that the center of gravity of the valve-side arm 84 can be moved toward the valve. Depressed part 1 on adjacent wall surface 100
02, the valve side arm portion center line L3
Can be displaced toward the valve-side separating wall 98 side from the position shown by the conventional broken line, and the valve-side arm portion center line L3
Can be made to approach or polymerize in the screw hole 96.

For this reason, the rocker arm 60 structure allows the valve-side arm center line L3 to approach or overlap the screw hole 96, thereby reducing the load from the valve 22 side to the vicinity of the valve-side arm center line L3. In addition, it can be received on the valve-side arm portion center line L3, the torsion can be reduced, the strength can be made advantageous, and the weight can be reduced.

The rocker arm 60 has a cam-side proximity lightening portion 110 and a cam-side separation lightening portion 112 provided on a cam-side proximity wall surface 106 and a cam-side separation wall surface 108 of a cam-side arm portion 82, respectively. A valve-side proximity lightening portion 114 that is continuous with the cam-side proximity lightening portion 110 is provided at least on the valve-side proximity wall surface 100 of the valve-side proximity wall surface 100 and the valve-side separation wall surface 98 of the side arm portion 84,
By not providing the valve-side separating lightening portion 116, the valve-side arm portion 84 can be reinforced.

Therefore, the rocker arm 60 structure can increase the rigidity of the portion A, which is disadvantageous in terms of strength due to the generation of the maximum principal stress due to torsion, and can be advantageous in terms of strength.
Torsion can be reduced.

In the above-described embodiment, the valve-side separating wall portion 98 of the valve-side arm portion 84 is not provided with the valve-side separating lightening portion 116 as shown by a dashed line in FIG. As shown in FIG. 1, a valve-side proximity lightening portion 114 that is continuous with the cam-side proximity lightening portion 110 is provided, but the valve-side proximity lightening portion 114 is not provided as shown by a dashed line in FIG. You can also.

As described above, the rocker arm 60 further reinforces the valve side arm portion 84 by filling the valve side arm portion 84 without providing the valve side proximity lightening portion 114 and the valve side separation lightening portion 116. A portion A where the maximum principal stress occurs due to torsion and the strength is disadvantageous
Stiffness can be further enhanced, strength can be made advantageous, and torsion can be further reduced.

[0042]

As described above, according to the rocker arm structure of the present invention, the concave portion is provided on the valve-side proximity wall surface on the side close to the center line of the boss portion on the distal end side of the valve-side arm portion. The center line of the valve arm can be displaced toward the valve-side separating wall surface, and the center line of the valve-side arm can approach or overlap with the screw hole.

For this reason, the rocker arm can move the load from the valve side near the center line of the valve side arm or the center of the valve side arm by making the center line of the valve side arm approach or overlap with the screw hole. It can be received on a wire, torsion can be reduced, strength can be made advantageous, and weight reduction can be achieved.

Further, the rocker arm structure of the present invention
A valve connected to at least the valve-side proximity wall surface of the valve-side proximity wall surface on the side adjacent to the center line of the boss portion of the valve-side arm portion and the valve-side separation wall surface of the valve side separation wall, By providing the side proximity lightening portion, the valve side arm portion can be reinforced.

For this reason, the rocker arm structure can increase the rigidity of a portion disadvantageously strong in torsion due to torsion, can be advantageous in strength, and can reduce torsion.

[Brief description of the drawings]

FIG. 1 shows a rocker arm according to an embodiment of the present invention.
3 is a perspective view from the direction of arrow I of FIG.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a plan view of a rocker arm.

FIG. 4 is a perspective view from the direction of arrow I # in FIG. 3;

FIG. 5 is a sectional view of the engine.

FIG. 6 is a plan view of a rocker arm showing a conventional example.

FIG. 7 is a perspective view from the direction of arrow VII in FIG. 6;

8 is a sectional view taken along line VIII-VIII in FIG. 7;

FIG. 9 is a perspective view from the direction of arrow IX in FIG. 6;

[Explanation of symbols]

 2 Engine 52 Valve train mechanism 54 Camshaft 60 Rocker arm 66 Boss part 68 Cam sliding contact part 70 Adjust screw 82 Cam side arm part 84 Valve side arm part 96 Screw hole 98 Valve side separation wall surface 100 Valve side proximity wall surface 102 Depression part 106 Cam side proximity wall surface 108 Cam side separation wall surface 110 Cam side proximity lightening portion 112 Cam side separation lightening portion 114 Valve side proximity lightening portion 116 Valve side separation lightening portion

Claims (2)

[Claims] A boss portion having a cylindrical shape supported by a rocker shaft is provided. The boss portion is connected to a base end thereof, and the tip end of the boss intersects the boss portion axial direction of the boss portion to each other. A cam-side arm and a valve-side arm are provided extending in a direction away from each other, and the cam-side arm and the valve-side arm pass through each center of gravity of the boss in the axial direction and extend from each base end to each tip end. The center line of the cam-side arm and the center line of the valve-side arm, which are respectively drawn in a directed manner, pass through the center of the boss portion in the direction of the boss portion axis and are aligned with the boss portion center line drawn in a direction orthogonal to the boss portion axis. On the other hand, each base end side is provided in communication with the boss portion so as to be located on each side in the axial direction of the boss portion at each tip side, and the cam side arm portion is slidably contacted with a cam of a cam shaft at the tip end side of the cam side arm portion. A cam sliding contact portion, The screw hole of the adjusting screw, which is in contact with the valve stem of the valve, at the distal end of the valve-side arm is biased toward the valve-side separating wall surface on the side away from the center line of the boss with respect to the center line of the valve-side arm. In the rocker arm provided so as to move the center of gravity of the distal end of the valve-side arm toward the valve-side separating wall side, the valve-side proximity of the valve-side arm near the center of the boss at the distal end of the valve-side arm. Rocker arm structure characterized by providing a concave portion on the wall surface. 2. The cam-side proximity lightening portion and the cam-side separation wall, respectively, on the cam-side proximity wall surface on the side close to the boss center line of the cam-side arm portion and the cam-side separation wall surface on the separation side. A lightening portion is provided, and the cam-side lightening portion is provided at least on the valve-side proximity wall surface of the valve-side arm portion on the side close to the center line of the boss portion and on the valve-side separation wall surface on the side away from the valve side. The rocker arm structure according to claim 1, wherein a continuous valve-side proximity lightening portion is provided.