JPH072964Y2 - Tip for tappet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a tip for sliding contact with a cam, a push rod or the like in a tappet for an internal combustion engine.

[Conventional technology]

Conventionally, this kind of tappet for an internal combustion engine uses a sintered material having excellent wear resistance for a portion (referred to as a tip) that is in sliding contact with a cam, a push rod, or the like and needs wear resistance, General steel materials were used for the other parts such as the sleeve, and both were integrated by diffusion bonding or brazing. However, in recent years, in order to reduce the inertial weight of the valve operating system and enhance high-speed followability, a method has been adopted in which a sleeve is die-cast with a light alloy such as aluminum and integrated with a chip formed in advance with a wear resistant material. .

[Problems to be solved by the device]

By the way, in the case where a sleeve is formed by die-casting with a light alloy and at the same time, it is integrated with a chip made of a wear resistant material, it is generally necessary to take measures such as falling prevention and rotation prevention. Therefore, in the case of manufacturing the chip from a sintered material, as shown in FIGS. 3 and 4, a flange portion 2 for slidingly contacting a cam with a lower surface 1 and a flange portion 2 are integrally formed with the flange portion 2. Further, in a chip 6 composed of a boss 5 having a diameter smaller than that of the flange 2 and having a hemispherical recess 4 slidably contacting the push rod on the upper surface 3, an arc-shaped groove 7 is provided on the outer periphery of the boss 5 to prevent coming off. In addition, it is general that a pair of notches 8 are provided in parallel with each other in opposite portions of the boss portion 5 to prevent rotation. For such a chip shape, a method of forming the flange portion 2 and the boss portion 5 separately, sintering them, and then joining them to integrally form them, or mechanically preventing them from coming off and providing a rotation stopper is adopted. ing.

However, in the above conventional joining method,
Because the two parts are molded and sintered separately and then joined,
There is a problem that the process is complicated and the manufacturing cost increases. Further, the method by machining is not so problematic when a metal material is used, but has a problem that when a ceramic material is used, the processing is difficult and the processing cost becomes extremely high.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tappet tip that is easy to manufacture, inexpensive, and excellent in wear resistance.

[Means for Solving the Problems]

In order to achieve the above object, the present invention comprises a flange portion that is in sliding contact with a cam, and a boss portion that is integrally formed with the flange portion and has a diameter smaller than that of the flange portion. The bottom surface is provided with a linear groove in the longitudinal direction.

(Operation) In the tappet tip of the present invention, after the flange portion and the boss portion are integrally formed, a groove for retaining and preventing rotation is provided at two opposite positions of the boss portion by machining. Thus, not only metal materials but also difficult-to-process ceramic materials can be easily grooved after molding or sintering. The cross-sectional shape of the groove may be an arc shape or a square shape, but in the case of a brittle material such as a ceramic material, the arc shape is more preferable in the sense of avoiding stress concentration.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

1 and 2 show one example of the tappet tip of the present invention, FIG. 1 is a plan view and FIG. 2 is a sectional view.
In these drawings, reference numeral 10 is an arcuate flange portion, and the lower surface 11 of the flange portion 10 is a sliding contact surface with the cam. In addition, this flange portion 10 has this flange portion
A boss portion 12 having a diameter smaller than 10 is integrally formed, and a hemispherical recess 14 that is in sliding contact with the push rod is formed on an upper surface 13 of the boss portion 12. A pair of grooves 16 having a linear bottom surface 15 and being parallel to each other in the longitudinal direction are formed at two opposite positions on the outer periphery of the boss portion 12, respectively. The cross section of these grooves 16 is arcuate. Further, both the flange portion 10 and the boss portion 12 are made of a sintered material (wear resistant material) made of a metal material or a ceramic material.

In the case of manufacturing the tappet tip configured as described above, after the disc-shaped flange portion 10 and the boss portion 12 having a smaller diameter than the flange portion 10 are integrally molded, a pair is formed on the boss portion 12 of the molded body. The groove 16 is processed, and then the molded body after the processing is sintered to obtain a product. Alternatively, after integrally molding the flange portion 10 and the boss portion 12, the sintered body is manufactured by sintering,
Then, a pair of grooves 16 is formed in the boss portion 12 of this sintered body to obtain a tappet tip.

The tappet tip manufactured in this way has a boss
A tappet for an internal combustion engine can be obtained by forming a sleeve on the outer periphery of 12 by aluminum die casting and integrating the two. Then, in the tappet, the pair of grooves 16 of the boss portion 12 of the tappet tip is used to prevent slipping and rotation, so that the tip and the sleeve are firmly integrated and a tappet with the required performance is obtained. Can be easily obtained.

[Effect of device]

As described above, the present invention comprises a flange portion that is in sliding contact with a cam, and a boss portion that is integrally formed with the flange portion and has a smaller diameter than the flange portion. Since the bottom surface is provided with a linear groove in the longitudinal direction, after the flange portion and the boss portion are integrally formed, they are machined to two opposite locations of the boss portion,
By providing a groove that also serves as a retainer and a retainer, not only metal materials but also difficult-to-process ceramic materials can be easily grooved after molding or sintering, making it easy to manufacture, inexpensive, and durable. It has the effect of good wear resistance. Therefore, by die-casting a light alloy using the tappet tip of the present invention, it is possible to smoothly manufacture a lightweight tappet for an internal combustion engine that is excellent in wear resistance and inexpensive.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention.
The figure is a plan view, FIG. 2 is a cross-sectional view, FIGS. 3 and 4 show a conventional tappet tip, and FIG. 3 is a plan view,
The figure is a sectional view. 10 …… Flange, 12 …… Boss, 15 …… Bottom, 16 ……
groove.

Claims (1)

[Scope of utility model registration request] 1. A tappet formed by casting a tip made of a wear resistant material with a light alloy, and a flange portion that is in sliding contact with a cam, and a flange integrally formed with the flange portion and having a diameter smaller than that of the flange portion. It consists of a boss and
A tip for a tappet, characterized in that a groove having a linear bottom surface is provided in the longitudinal direction at two opposite positions on the outer periphery of the boss portion.