KR20100041111A - Cam follower rocker arm - Google Patents

Abstract

PURPOSE: A cam follower rocker arm. The body opening is formed into the leading end accomplishing the narrow width, the body sidewall and perpendicularity than the body sidewall. The stiffness and moment of inertia are optimized. CONSTITUTION: A cam follower rocker arm. The U- shape of a character body portion(17a) and roller(22a) are included. The U- shape of a character body portion has the sidewall in which the roller opening combining sidewall has. In roller is opening, the axle(24) for establishing roller in the sidewall of the body portion is had. The body opening is formed into the leading end accomplishing the narrow width, the body sidewall and perpendicularity than the body sidewall. Roller is formed into the step of offering the relatively small denotation width [peripheral width] according with the leading end.

Description

CAM FOLLOWER ROCKER ARM}

The present invention relates to a U-shaped body portion having an intermediate opening at the top and vice versa located inside the body and accessible through the opening, the axle being fixed to the side of the U-shaped body portion. A cam follower rocker arm having a roller installed on the back side).

A typical type of cam follower rocker arm is disclosed in US Pat. No. 4,825,717, the contents of which are incorporated herein by reference, and the present invention is an improvement therefrom. U.S. Patent No. 4,825,717 includes a U-shaped cross-section body portion having a middle opening that is the same width as the inner wall of the body portion. The cam follower roller is located between the body sidewall and the opening. When located in the body portion, the roller is captured between the side walls, extends into the intermediate opening, and rotates therein. The body portion of US Pat. No. 4,799,464 discloses the use of a rectangular opening for a boat style rocker arm of U-shaped cross section. This type of rocker arm differs from the cam follower type in that the boat style rocker arm is supported centrally by a pedestal with shanks that extend through the window. Ships perpendicular to the side wall of the boat style arm are used to carry loads in operation.

The technical problem of the present invention is to provide a cam follower rocker arm having high stiffness and optimizing stiffness and moment of inertia.

The present invention is distinguished from the prior art having a body portion having a tip opening with an outer width less than an inner width in the body opening making a ledge perpendicular to the body sidewall. Cylindrical rollers, when expanded, allow the smaller width of the roller to extend to the outer window at both ends thereof, and when assembled, the larger width to maintain a closed running clearance on the side wall of the body. Has a transition step. A tip opening or window in the portion joining the two vertical sides of the U-shaped body portion may be formed at the top and bottom of the U-shaped body portion. This tip functions to provide a structure that improves rocker arm stiffness as can be demonstrated using analytical tools and acutive static testing. It is not desirable to grind the tip below the roller outer surface diameter. This increases the stiffness of the rocker arm but significantly increases the overall mass and moment of inertia compared to conventional cam follower rocker arms. Optimizing stiffness and moment of inertia is an important key to contributing to overall engine performance.

The cam follower rocker arm according to the invention optimizes the stiffness and moment of inertia while improving the stiffness of the rocker arm.

The rocker arm according to the invention is of a cam-follower type, preferably manufactured by cold forming and has two structurally-integral side walls joined by vertically positioned walls, most of which are full length. It includes an integral metal body portion which is a common convex body having a U-shaped cross section through. The rocker arm body portion is adapted to receive the end of the recess and valve stem formed at one end that receives the upper part of the lifter post on which the rocker arm can rotate. And a second recess at the opposite end of the body portion. The central portion of the wall joining the sides of the U-shaped body portion generally has a rectangular opening. The width or lateral size of the rectangular opening is smaller than the width of the top wall so that the opening extends substantially, but not entirely, from one side to the other side of the rocker arm body portion.

A cam-contacting roller having a stepped periphery is mounted to the body and by a rocker arm that allows the outer peripheral surface of the stepped roller to be exposed through an rectangular body opening that engages the cam. It is rotatably carried. The cam-contact roller is rotatably mounted on the axle carried by the side wall of the body portion below the rectangular opening. The roller preferably has a plurality of needle bearings to provide minimal friction.

With reference to the drawings and as shown in FIG. 1, the valve train 10 is a hydraulic lash adjuster that engages at one end of the cam follower rocker arm 11 and the cam follower rocker arm 11. 12) located between the valve stem 13 and the hydraulic lash adjuster 12 and the valve stem 13 in contact with the other end of the cam follower rocker arm 11 and in contact with the cam follower rocker arm 11. It consists of the cam 14. The valve stem 13 extends upwardly from a cylinder head (not shown) through a coiled compression spring 15 and a retaining ring 16 installed in the valve stem 13, where the coiled compression spring 15 ) Is typically mounted opposite to the cylinder head. The cam 14 is rotatable. The rotational operation of the cam 14 rotates about the hydraulic lash adjuster 12 and is transmitted through a cam follower rocker arm 11 which moves the valve stem 13 in a linear motion.

In FIG. 2, the cam follower rocker arm 11 engages a first lower section 20 (FIG. 1) in contact with the valve stem 13 and a second lower section 21 (FIG. 1) that couples the hydraulic lash regulator 12. It consists of a U-shaped body 17 having a vertical surface 18 joined together by 1). Both lower sections 20, 21 extend at right angles to the vertical surface 18. The cylindrical roller 22 preferably provided in the cylindrical needle 23 is installed on the cylindrical axle 24. The roller 22 is in contact with the cam 14 (FIG. 1) and is located between the vertical surface 18 and extends to the intermediate rectangular window surface 25. Surfaces 26, 27 extend through lower sections 20, 21, respectively, and are wide enough to allow clearance to roller 22.

As shown in FIG. 3, the window surface 25 is the same width as the vertical surface 18. The roller end surface 28 and the vertical surface 18 essentially have a total clearance throughout of about 0.2 to 0.8 when assembled. The roller outer periphery 29 and roller end (corner) surface 28 extend into rectangular window surfaces 25, 26 (FIG. 2) and 27 (FIG. 2) with clearance.

In FIG. 4, the cam follower rocker arm 11 of the present invention has a lower section 20a having an end contacting the valve stem 13 (FIG. 1) and an opposite end engaging the hydraulic lash regulator 12 (FIG. 1). It consists of a U-shaped body portion 17a having a vertical side surface 18a joined together by means of. The lower section 20a is perpendicular to the vertical surface 18a. The cylindrical roller 22a and the cylindrical needle 23 are installed on the cylinder type axle 24. The roller 22a is in contact with the cam 14 of FIG. 1 and is located between the vertical surface 18a and the intermediate rectangular window surface 25a. Surfaces 26a and 27a extend through the lower section 20a and are wide enough to allow clearance to the roller 22a.

In FIG. 5, the window surface 25a is smaller than the vertical surface 18a which makes the shelf with 30% material thickness of the minimum distance. The roller 22a has a transition surface 30a at both ends allowing a total clearance of 0.2 to 0.8 between the vertical surface 18a and the roller end surface 28a. The roller outer surface 29a and the roller transition surface 30a extend to rectangular window surfaces 25a, 26a (FIG. 4) and 27a (FIG. 4) with clearance.

The present invention is described in particular embodiments, but the present invention is not limited thereto. For example, preferred body shapes generally comprise a U-shaped cross section, but the body portion need not be so limited. Various additional variations can be made in the size and arrangement of components used while still obtaining the benefits of the present invention. Accordingly, the invention is limited only by the scope of the appended claims.

1 is a typical end pivot over a head cam valve train with a cam follower rocker arm, a valve stem and a hydraulic lash adjuster.

2 is a cross-sectional view of the prior art showing components for a cam follower rocker arm.

3 is a cross-sectional view of FIG. 2 adopted at the center of the roller.

4 is a cross-sectional view of the present invention showing components for a cam follower rocker arm.

5 is a cross-sectional view of FIG. 4 adopted at the center of the roller.

Claims (6)

A generally U-shaped body with sidewalls with roller openings joining the sidewalls, Consisting of a roller having an axle for installing the roller on the side wall of the body portion at the opening, Wherein the body opening has a narrower width than the body sidewall and a tip perpendicular to the body sidewall, wherein the roller is formed with steps providing a relatively small peripheral width coinciding with the tip. The method of claim 1, A cam follower rocker arm that permits sole access to a smaller width of the roller periphery. The U-shaped cross-sectional body portion of claim 1 having an intermediate window opening smaller than the body inner width that creates a tip perpendicular to the body sidewalls. The roller of claim 1 having a transition on both sides that allows a smaller width to extend into the window of claim 2 and maintains a larger clearance on the inner wall of the body of claim 2. The inverted U-shaped cross-sectional body portion of claim 1 having an intermediate window opening smaller than the body inner width that creates a tip perpendicular to the body sidewalls. A spacer (not shown) on either side of the roller which causes the roller to extend into the window of claim 2 and maintains the closing clearance on the inner wall of the body part of the stack-up The roller of claim 1 to be used.

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