JPS6035107A - Method of manufacturing locker arm for internal- combustion engine - Google Patents

Abstract

PURPOSE:To simplify the manufacturing process and reduce the cost, by chamfering the corner part etc. of an installation surface of a ceramic pad to a locker arm when a ceramic pad is formed and machining the pad-to-cam contact surface after the pad has been fixed to the arm. CONSTITUTION:The tip portion of a locker arm 1 has a ceramic pad 2 firmly attached to it. A supporting surface 3 for the locker arm is formed in a plane nearly perpendicular to the direction of rocking motion of the tip portion of the locker arm 1. In addition, a reference surface 5 is formed in order to position the ceramic pad 2 properly with respect to a rocking shaft 4. In this case, a chamfered section 7 is provided in order to keep the pad 2 free from a corner part 6, which is used to bring the ceramic pad 2 into complete contact with both the supporting surface 3 and the reference surface 5 for the accurate positioning of the ceramic pad 2 when the pad 2 is formed. And after the ceramic pad 2 is fixed to the locker arm 1, a contact surface 8 between the pad 2 and a cam, which is formed on the opposite side of the supporting surface 3 of the ceramic pad 2, is machined for finishing.

Description

[Detailed description of the invention] Technical field The present invention relates to a method for manufacturing a rocker arm for an internal combustion engine.

In order to improve the wear resistance of the sliding surface of the rocker arm (1) against the cam in a conventional valve train for an internal combustion engine, a ceramic pad is fixed to the tip of the rocker arm. Methods for fixing the ceramic band to the rocker arm include a method of integrally casting the ceramic pad with the rocker arm forming material (Japanese Utility Model Publication No. 56-109607), a method of gluing the ceramic pad to the rocker arm, or a method of bonding the ceramic pad to the rocker arm. A method of mechanically connecting the rocker arm to the rocker arm
9005) etc. have been proposed. In the bonding method and mechanical bonding method, a pad support surface is formed at the tip of the rocker arm, and a position reference surface extending at right angles from this support surface is formed, and these support surfaces and position reference surfaces form an angle. It becomes a surface.

The ceramic pad, including the cam contact surface, is finished using a special grinding wheel. This grinding process is only possible using a special grindstone, and the fact that the ceramic pad is relatively small increases the cost required for such a process.

Object of the Invention (2) An object of the invention is to provide an inexpensive method of manufacturing a rocker arm to which a ceramic pad is fixed as described above.

Structure of the Invention In the present invention, the corners corresponding to the corners of the pad mounting surface of the ceramic pad and the corners around the cam contact surface are chamfered during molding of the ceramic pad, and the ceramic pad is fixed to the rocker arm. , characterized in that the cam contact surface of the pad is machined after fixation.

Embodiment Referring to FIG. 1, a ceramic band 2 is fixed to the tip and first part of a rocker arm 1. In this embodiment, the ceramic pad 2 is fixed to the rocker arm 1 by adhesive. Therefore, a support surface (joint surface) 3 is formed on the rocker arm 1 in a plane substantially perpendicular to the rocking movement direction of the tip end thereof. A reference surface 5 is formed for positioning the ceramic pad 2 with respect to the swing shaft 4. The ceramic pad 2 is in contact with the support surface 3 and the reference surface 5 (3
) is glued on the supporting surface 3.

As shown enlarged in FIG. 2, the support surface 3 and the reference surface 5
The corner 6 between the two is generally not a perfect intersection of planes, but a rounded corner. In order to accurately position the ceramic pad 2 in complete contact with the support surface 3 and the reference surface 5, a chamfer 7 is required to escape the corner 6. In the present invention, this chamfering 7 is performed when the ceramic pad 2 is molded. Conventionally, chamfering 7 was performed after molding the ceramic pad, and since the pad itself was small, chamfering was not an easy task.

The ceramic pad 2 is formed with a contact surface 8 with a cam (not shown) on the opposite side of the support surface 3. It goes without saying that the contact surface 8 is contoured when the ceramic pad is molded, but since this is an important surface, the ceramic pad 2
After applying the adhesive 1 to the rocker arm 1, precision finishing is performed integrally with the rocker arm.

As shown in FIGS. 2 and 3, the corners of the cam contact surface 8 of the ceramiso (4) cupasod 2 are also chamfered. These chamfered surfaces are indicated by reference numeral 9 as an inclined surface extending parallel to the support surface 3, reference numeral 10 as an inclined surface extending parallel to the reference surface 5, and reference numeral 11 as an inclined surface at the intersection of the double-ended inclined surfaces. There is. All these chamfers are formed when the ceramic pad 2 is molded, and therefore, the chamfers are already completed when the ceramic pad 2 is bonded.

By providing such a chamfer, it becomes possible to prevent the ceramic pad 2 from cracking or chipping during the bonding work, the movement to the cam contact surface finishing process, and the cam contact surface finishing process. As with the corner chamfering of the mounting surface described above, these chamfers do not require machining using a grinding wheel.

Further, if the ceramic pad 2 is formed in a symmetrical shape as shown by the reference numeral 7', the attachment of the ceramic pad 2 can be avoided without mistakes.

Although the above explanation has been given as an example of fixing the ceramic pad to the rocker arm by adhesive, it is also possible to fix it using fastening means such as bolts or rings (5).

Effects As explained above, according to the present invention, a rocker arm with a ceramic pad can be manufactured reliably at low cost.

[Brief explanation of drawings]

1 is a front view of a rocker arm according to the present invention, FIG. 2 is a front view of the ceramic pad of FIG. 1, and FIG. 3 is a side view of the ceramic pad of FIG. 2. ■...Rocker arm, 2...Ceramic pad,
3... Support surface, 5... Reference surface, 7 River corner chamfering, 8
...Cam contact surface, 9,10. If... Surrounding chamfering. (6)

Claims (1)

[Claims] A rocker arm for an internal combustion engine, in which a pad mounting surface having a corner is formed at the tip of the rocker arm, and a pad made of ceramic is fixed to the rocker arm by contacting the pad mounting surface, the band mounting surface of the ceramic band. The corners corresponding to the corners of the ceramic pad and the corners around the cam contact surface are chamfered during molding of the ceramic pad, the ceramic pad is fixed to the rocker arm, and the cam contact surface of the pad is machined after fixing. A method for manufacturing a rocker arm for an internal combustion engine, characterized by: