JP2802555B2 - Roller rocker arm - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller rocker arm used for a valve train of an internal combustion engine, and more particularly to a roller rocker arm for reducing a load on a camshaft.

[0002]

2. Description of the Related Art In an OHC type valve operating mechanism, one end of a rocker arm is supported by a pivot shaft, and the rocker arm is swung up and down by a cam disposed above an intermediate portion of the rocker arm. There is an end pivot (swing arm) type that opens and closes a valve.

In this end pivot type valve train, the rocker arm and the cam are generally in sliding contact with each other, so that the mechanical loss due to friction is relatively large and the load on the camshaft increases. As a result, fuel efficiency and output are reduced.

Recently, as a solution to this problem,
Various roller rocker arms have been proposed in which a rotatable roller is provided at a sliding contact portion of a rocker arm with a cam so as to make rolling contact to reduce friction loss.

[0005]

[0004] Recent automobile engines tend to have high output and high rotation, for example, by mounting a supercharger or adopting a multi-valve mechanism. It is effective to increase the permissible rotation speed in order to obtain high output with an engine with the same displacement. To increase the permissible rotation speed, the components of the valve train must be devised to improve the valve and rocker arms. It is necessary to improve the following performance of the cam.

[0006] The roller rocker arm has a disadvantage that the weight increases by the amount of the added roller compared to a normal sliding contact type rocker arm, and follows the rotation of the cam to the rotation of the cam without slipping to a high rotation range. It is difficult to do so, and this is an obstacle to increasing the permissible engine speed.

That is, generally, as the engine rotates at a higher speed, the followability of the rollers of the roller rocker arm is impaired, the slip occurs, and the roller comes into sliding contact, and the advantage of the roller rocker arm is lost.

In this case, the mechanical loss due to friction increases as in the case of the ordinary rocker arm described above.
Since the load on the camshaft increases, the allowable rotation speed of the engine must be set lower.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to apply a rotation assisting force to a roller in a system different from a camshaft to reduce a load on the camshaft. An object of the present invention is to provide a roller rocker arm capable of increasing the allowable rotation speed of an engine by increasing the followability of a roller to a cam.

[0010]

In order to achieve the above-mentioned object, the present invention provides a rocker arm body having a vertically oriented fitting hole formed in a substantially central portion of the rocker arm body and having a front-rear direction supported by the rocker arm body. In a roller rocker arm that accommodates a roller that rotates around an axis such that the upper end surface thereof comes into contact with a rotating cam, at least one of the side surfaces facing the axial direction of the roller, a plurality of protrusions are radially formed. In addition to providing a protruding impeller, the roller is provided with a forward rotation assisting force in a proper position of the rocker arm main body by being connected to an appropriate hydraulic pressure generation source and discharging lubricating oil toward the impeller. The discharge nozzle is provided as described above.

[0011]

The roller receives the forward rotation assisting force by a hydraulic power different from that of the camshaft, so that the load on the camshaft is reduced, and the roller and the cam do not slip until a high rotation range. Therefore, the followability at the time of high-speed rotation is enhanced, and the allowable rotation speed of the engine can be increased.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an end pivot (swing arm) having a roller rocker arm (R) according to an embodiment of the present invention.
A rocker arm body (1)
Is connected to a pivot shaft (3) of a known hydraulic valve lash adjuster (3) incorporated in the cylinder head (2).
a) is pivotally supported by fitting from above into the spherical portion (3b) at the upper end, and the other end is also a pair of cotters (4) (4), a spring retainer (5), and a valve spring (6). And the like, abut the stem end (7a) of the engine valve (7) assembled to the cylinder head (2).

As shown in FIGS. 2 and 3, the rocker arm main body (1) has a pivot receiving block (9) between two left and right long side plates (8) and (8) at one longitudinal end. , And a stem contact block (10) to the other end side, and furthermore, both side plates (8)
A roller (11) is sandwiched between a pair of right and left fixing members, each of which is surrounded by (8) and both blocks (9) and (10), and is formed with a fitting hole (1a) facing vertically. The rivet (12) is penetrated through the both side plates (8) and the blocks (9) and (10), and the insertion ends thereof are caulked to be integrally connected as a whole.

The both side plates (8) and the blocks (9) and (10) are provided with through holes (13a) and (13b) through which the rivets (12) pass, respectively. Further, the blocks (9) and (10) have Small-diameter through holes to be engaged with protrusions (14) projecting inward at both ends of both side plates (8)
(15) is provided. When the blocks (9) and (10) are sandwiched by the side plates (8), the blocks (9) and (10)
Engages with the side plate (8) at two places of the through holes (13b) and (15),
The rotation about the axis is suppressed.

A vertically extending fitting hole (1) formed by being surrounded by both side plates (8) and both blocks (9) and (10).
The roller (11) provided at the center of (a) is provided with a small-diameter rotary shaft (16) protruding in the longitudinal direction of the axis, and a shaft hole (17) provided in both side plates (8).
By loosely fitting to the shaft, it is pivotally supported rotatably.

When both rotating shafts (16) are pivotally supported by the side plate (8), the upper end of the outer periphery of the large diameter portion of the roller (11)
(8) A roller body (11a) positioned above the upper side (8a), and a plurality of ridges (18a) on the front and rear sides facing the axial direction of the roller body (11a) at a fixed interval. It consists of an impeller (18) that protrudes radially every other.

The distance (a) between the impeller (18) protruding from the front side in the axial direction of the roller (11) and the tip of each protruding ridge (18a) of the impeller (18) also provided on the rear side. Is
It is slightly smaller than the front and rear length (b) of both blocks (9) and (10), and can rotate easily even if the roller (11) is sandwiched between both side plates (8). However, the difference (ba) is equal to the roller (11).
But it's not big enough to play back and forth.

A hemispherical pivot bearing hole (19) is formed in the lower surface of the pivot receiving block (9) so as to fit from above into the spherical portion (3b) at the upper end of the pivot shaft (3a). Above the bearing hole (19), a through hole (20) penetrating in the front-rear direction is provided, and the center of the through hole (20) is
It communicates with the pivot bearing hole (19) immediately below via (a).

Furthermore, a side plate of the pivot receiving block (9)
One end of each of the front and rear surfaces (9a) and (9a) contacting with (8) has a through hole (20).
A groove (21) communicating with the groove (21) is formed, and the other end of the groove (21) is
At the block end surface (9b) close to the outer peripheral surface of (11),
The tip is slightly narrowed to open as a lubricating oil discharge nozzle (22).

The direction of emission of the lubricating oil from the discharge nozzle (22) is determined by a roller rotated by a rotary cam (24) fixed to a cam shaft (23) provided immediately above the roller (11).
The lubricating oil is directed in a direction approximately similar to the tangential direction of the outer circumference of the roller body (11a) so that the rotation assisting force in the same direction (forward direction) as the rotation direction of (11) is applied.
It can radiate toward (18).

The lubricating oil radiated toward the impeller (18) is supplied to a through hole (25) passing through a pivot shaft (3a) of the valve lash adjuster (3) and an oil provided in a cylinder head (2). It is sent from an appropriate hydraulic pressure generation source through a through hole (26) communicating with the gallery.

When the pressurized lubricating oil is radiated to the impeller (18), a rotational force is generated in the roller body (11a), and the rotational force is brought into sliding contact with the rotating cam (24) to rotate the roller (11). As a result, the load on the camshaft (23) is reduced.

This means that the operating resistance of the roller rocker arm (R) is reduced when viewed from the camshaft (23) side. That is, the same operation is performed as the apparent rotational inertial mass of the roller (11) is reduced. As a result, the resistance force of the rotating cam (24) for rotating the roller (11) is reduced, and the limit rotational speed at which slippage occurs between the rotating cam (24) and the roller (11) is increased.

Further, by making the pressure of the lubricating oil correspond to the rotational speed of the engine so that the lubricating oil has a high pressure when the engine is running at a high speed, the roller ( The rotation of 11) can be made to follow the rotation of the rotary cam (24).

In this embodiment, the lubricating oil is supplied from the valve lash adjuster (3). However, a separate hydraulic system path may be provided to radiate the lubricating oil to the impeller (18). Good.

The rocker arm body (1) is pivotally supported by a hollow rocker shaft instead of the valve lash adjuster (3), and lubricating oil supplied to the hollow hole is impeller.
(18) may be radiated. The roller (11) may be a bearing type roller using a needle roller or the like.

[0027]

According to the present invention, the roller receives the forward rotation assisting force by hydraulic power different from that of the camshaft, so that the load on the camshaft is reduced.
There is no slippage between the roller and the cam up to the high rotation range, the followability during high-speed rotation is improved, and the allowable rotation speed of the engine can be increased.

Further, since the slip between the roller and the cam is eliminated in the high rotation range, the generation of frictional heat is small, and the amount of change in the valve clearance due to the thermal expansion of the roller and the like can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a central longitudinal section showing an embodiment of the present invention and a mounting example thereof.

FIG. 2 is a plan view taken along the line AA in FIG.

FIG. 3 is an exploded perspective view of the roller rock arm shown in FIG. 1;

[Explanation of symbols]

(1) Rocker arm body (1a) Fitting hole (2) Cylinder head (3) Valve lash adjuster (3a) Pivot shaft (3b) Spherical part (4) Cotta (5) Spring retainer (6) Valve spring (7) Engine Valve (8) Side plate (8a) Upper side (9) Pivot receiving block (9a) (9a) surface (9b) Block end surface (10) Stem contact block (11) Roller (11a) Roller body (12) Rivet (13a) ( 13b) Through hole (14) Projection (15) Through hole (16) Rotating shaft (17) Shaft hole (18) Impeller (18a) Ridge (19) Bearing hole (20) Through hole (20a) Through hole (21) Groove (22) Discharge nozzle (23) Camshaft (24) Rotating cam (25) Through hole (26) Through hole (R) Roller rocker arm

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01L 1/18 F01M 1/06 F01M 9/10

Claims (1)

(57) [Claims] A roller that rotates about a forward-backwardly supported axis supported by the rocker arm main body is provided in a vertically oriented fitting hole formed at a substantially central portion of the rocker arm main body. In the roller rocker arm housed in contact with the roller, at least one of the side surfaces facing the axial direction of the roller is provided with an impeller in which a plurality of ridges are projected radially, and in an appropriate position of the rocker arm body, A roller rocker arm provided with a discharge nozzle which is communicated with an appropriate hydraulic pressure generation source and discharges lubricating oil toward the impeller to apply a forward rotation assisting force to the roller. .