JPH09242514A - Tappet manufacturing method - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To easily adjust the pressure applied to a ceramic chip of a tappet body during heat treatment, and to improve the productivity in the production of various small quantities. A base plate (24) having a peeling property with respect to a brazing material (23)
The ceramic chip 22 is arranged on the ceramic chip 22, and the tappet body 21a is placed on the ceramic chip so that the bottom surface 21b overlaps the brazing material 23, and a load is applied to the upper part. In this state, heat treatment is performed and the ceramic chip is brazed to the bottom surface. A weight 27 is loaded on the fixture 26 that is inserted and fixed in the push rod insertion hole 21c to apply a load to the upper portion of the tappet body 21a. It is preferable to form a recess 24a in the base plate that accommodates the ceramic chip and the bottom of the tappet body and can be fixed in an overlapping state. A shaft portion 26b is formed at the center of the fixture so as to match the axis of the tappet body, and a weight having a hole 27a or a groove formed therein may be fitted into the shaft portion to be loaded on the fixture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a tappet provided under a push rod. More specifically, the present invention relates to a manufacturing method suitable for manufacturing small quantities of tappets in which ceramic chips are brazed so as to cover the bottom surface of the tappet body.

[0002]

2. Description of the Related Art A four-cycle engine is usually equipped with a valve system. The valve is generally shaped like a mushroom and is closed by the force of a coil spring. By opening this valve, it is possible to perform intake and exhaust in the operation process of 4 cycles,
Gas can be exchanged between the combustion chamber and the cylinder from the opened valve. The device that opens the valve by pressing it connects the rotation of the crankshaft to the camshaft with a timing belt, chain, or gear, and opens and closes the valve via a rocker arm by rotating the substantially oval cam provided on the camshaft with the shaft. Let The valve system can be classified according to the position where the camshaft is provided. The so-called overhead camshaft system and the overhead valve system (hereinafter referred to as OH
V).

As shown in FIG. 4, in the OHV, one end of a rocker arm 18 is pushed up through a pair of push rods 17 which are erected by the rotation of a cam shaft 12 positioned horizontally on the cylinder side, and the arm 18 is a seesaw type. The valve 19 is pushed down and opened.
The cam 1 of the camshaft 12 is located below the push rod 17.
A tappet 21 that abuts 6 is mounted, and the push rod 17 is configured to move up and down by rotation of the cam 16 via the tappet 21.

On the other hand, since the tappet 21 provided under the push rod 17 is always in contact with the cam 16 and the cam 16 rotates, the tappet 21 always rubs against the cam 16, so that wear resistance is required. Particularly in recent years, the tappet 21 is required to have very high wear resistance in order to cope with higher engine output and the like. In order to satisfy this requirement of wear resistance, a technique of brazing a ceramic chip so as to cover the bottom surface of the tappet body has been developed. The brazing of this ceramic tip is done by applying heat to the bottom of the tappet body by applying an appropriate load between the bottom and the ceramic tip according to the type of brazing material or the material of the ceramic tip or tappet body. Ceramic chips are brazed. By brazing the ceramic chip on the bottom surface of the tappet body in this manner, the durability of the tappet 21 that abuts on the cam 16 can be improved by utilizing the excellent wear resistance of the ceramic. Conventionally, when pressurizing the tappet body to the ceramic chip during heat treatment, after placing the brazing material and the tappet body on the ceramic chip and putting it in the heat treatment furnace, the tappet is used from outside the heat treatment furnace using an air cylinder or spring. Pressure was being applied to the top of the body.

[0005]

When a large amount of the same tappet is manufactured by using the same type of ceramic chips and brazing material, the productivity is not lowered even if the pressure is applied by the above method. However, when the types of ceramic chips or brazing materials are increased and a large number of small amounts of tappets are manufactured in the same heat treatment furnace, there is a problem that the conventional method is inefficient and the pressure cannot be easily changed. It is an object of the present invention to provide a method for manufacturing a tappet, in which the pressure applied to the ceramic chip of the tappet body can be easily adjusted at the time of heat treatment and the productivity is high in the manufacture of various small quantities.

[0006]

The invention according to claim 1 is
As shown in FIG. 1, the ceramic chip 22 is arranged on a base plate 24 having a peeling property with respect to the brazing material 23, and the tappet body 21 a is placed on the ceramic chip 22 via the brazing material 23.
Of the tappet body 21a so that the bottom surface 21b of the tappet body overlaps, a load is applied to the upper portion of the tappet body 21a, and heat treatment is performed in this state to braze the ceramic chip 22 to the bottom surface 21b of the tappet body 21a. Is. Its characteristic structure is that the tappet body 21a
The weight is applied to the upper part of the tappet body 21a by loading one or more weights 27 on the fixture 26 fixed by being inserted into the rocker arm insertion hole 21c. By increasing or decreasing the weight 27 loaded on the fixture 26, the load applied to the upper portion of the tappet body 21a can be easily changed.

Examples of the material of the tappet body 21a include structural carbon steel and structural alloy steel.
M630 and SNCM616 are illustrated. The tappet body 21a is manufactured by forging or cutting such a steel material, and the bottom surface 21b is ground or polished in a post process.
The ceramic chip 22 includes Si ₃ N ₄ , SiC, Al.
Examples include ₂ O ₃ and zirconia. The plate thickness is set so as to ensure at least a strength capable of withstanding the impact received from the cam, and is preferably 1.0 mm to 2.0 mm.
More preferably, it is 2 mm to 1.8 mm. The brazing material 23 is Ti
Silver rhodium containing is typically used. As other brazing material, Ag-Cu-Ti system, Ag-Cu-Ti-Zn system, A
g-Ti system, Cu-Ti system, or Ag-Cu-Ni-T
Examples include i-type. Further, the brazing surface of the ceramic chip 22 may be preliminarily subjected to a metallizing process by a vapor deposition method or the like. In that case, Ag—Cu based and Ag—Cu—In based brazing materials are preferable. The atmosphere at the time of brazing is preferably a non-oxidizing atmosphere such as vacuum, argon gas, hydrogen gas, nitrogen gas. In the case of a Ti-containing brazing material, brazing may be performed in a vacuum or an argon gas or an atmosphere in which these are combined. preferable.

The invention according to claim 2 is the invention according to claim 1, wherein the ceramic chip 22 and the tappet body 21 mounted on the ceramic chip so that the bottom surface 21b overlaps each other.
This is a method for manufacturing a tappet in which a recess 24a that accommodates the bottom 21b of a and can be fixed in an overlapping state is formed on the base plate 24. Examples of the material of the base plate 24 include carbon and a ceramic material such as Al ₂ O ₃ which has a releasability for the brazing material. The base plate 24 includes a ceramic chip 22 and a bottom surface 21.
The recess 24a is preferably formed to have a diameter slightly larger than that of the ceramic chip 22 and the bottom surface 21a in order to braze a on the same axis.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein a shaft portion 26b is formed at the center of the fixture 26 so as to match the shaft center of the tappet body 21a, and the shaft portion 26b is formed. Is a method for manufacturing a tappet in which a weight 27 having a hole 27a or a groove that can be fitted into the shaft 26b is fitted into the fixture 26 to be loaded on the fixture 26. Weight 27 and shaft 26
By fitting into b, heat treatment can be performed in a stable state, and by forming the shaft portion 26b so as to match the axial center of the tappet body 21a, it is possible to apply a load evenly to the entire bottom surface of the tappet body 21a. .

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. As shown in FIGS. 1 to 3, the tappet 21 includes a ceramic tip 22 and a tappet body 21.
It is brazed so as to cover the bottom surface 21b of a. The tappet body 21a is made by cutting a metal member such as JIS standard SNCM630, and the ceramic chip 2
Examples of 2 include Si ₃ N _{4 and the} like. The ceramic chip 22 is a silicon nitride sintered body and has a diameter of 38 m with both surfaces polished and finished.
The surface roughness Ra of the joint surface of a circular plate of m and a thickness of 1.5 mm
Is polished to 0.2 to 0.3 μm. The tappet body 21a has a large diameter portion of 38.5 mm and a small diameter portion of 22.
It is processed into a substantially mushroom shape having a height of 8 mm and a height of 5.5 mm, and the lower surface of the large diameter portion, that is, the bottom surface 21b has a surface roughness Ra of 0.2 to.
Polished to 0.3 μm. As shown in FIG. 2, the small diameter portion has a hole 21c into which the lower end of the push rod 17 is inserted, and a recess 21d with which the lower portion of the push rod 17 is engaged is formed in the lower portion of the hole 21c. As shown in FIG. 1, when the ceramic chip 22 is brazed to the bottom surface 21 b, the ceramic chip 22 is placed on a base plate 24 that is peelable from the brazing material 23, and the brazing material 2 is placed on the ceramic chip 22.
The tappet main body 21a is placed so that the bottom surfaces of the tappet main body 21a overlap with each other via 3. A load is applied to the upper portion of the tappet body 21a, and the ceramic chip 22 is brazed to the bottom surface 21b of the tappet body 21a by heat treatment in this state.

The characteristic structure of the present invention is that the tappet body 2 is used.
1 or 2 or more weights 27 are loaded on the fixture 26 fixed by being inserted into the rocker arm insertion hole 21c of 1a, thereby applying a load to the upper portion of the tappet body 21a. Base plate 24 on which the ceramic chip 22 is arranged
The recess 24a has a depth capable of accommodating the ceramic chip 22 and the bottom of the tappet body 21a placed so that the bottom 21b overlaps the ceramic chip 22, and is slightly smaller than the outer diameters of the ceramic chip 22 and the bottom 21b. Largely formed. Therefore, the ceramic chip 22 and the tappet main body 21a on which the bottom surface 21b is overlapped are fixed concentrically in an overlapping state. A hole 2 for inserting the rocker arm of the tappet body 21a is provided at the bottom of the fixture 26.
A cylindrical insertion portion 26a to be inserted into 1c is formed, and the insertion portion 26a has a diameter slightly smaller than the hole 21c.
Further, the tappet body 21a is provided at the center of the upper portion of the fixture 26.
Is formed with a shaft portion 26b coinciding with the shaft center of
A weight 27 is fitted in b.

A hole 27a or a groove is formed in the center of the weight 27, and the hole 27a or the groove is fitted in the shaft portion 26b so that the weight is loaded on the fixture 26. In this embodiment, the weight of the weight 27 is 300 to 500 g.
f, and the pressure on the bottom surface of the tappet body 21a is 27 to 45 gf / cm ² . This load or pressure can be appropriately changed depending on the material of the ceramic chip or the brazing material, the surface roughness or the thickness. Bottom 2 of ceramic chip 22
The brazing to 1b is performed by first arranging the ceramic chip 22 in the recess 24a of the base plate 24, then superposing the active brazing material (foil) 23 on the ceramic chip 22 concentrically.
Further, the tappet body 21a is placed with the active brazing material (foil) 23 interposed therebetween so that the bottom surfaces 21b overlap each other. In this state, a predetermined pressure is applied to the joint surfaces of the ceramic chip 22 and the bottom surface 21b.

A predetermined pressure is applied using the fixture 26. That is, the insertion portion 26a provided at the bottom of the fixture 26
The hole 21c for inserting the rocker arm of the tappet body 21a
The fixture 26 by inserting it into the tappet body 21a.
Fixed to Next, a weight 27 is attached to the shaft portion 26b of the fixture 26.
Insert as many as you need. The joining pressure between the ceramic chip 22 and the bottom surface 21b is adjusted by increasing or decreasing the number of weights 27. Next, the tappet body 21a and the ceramic chip 22 in the pressurized state shown in FIG.
Is moved together with the base plate 24 into the heat treatment furnace for heat treatment. The heat treatment is performed by first raising the temperature from room temperature at a rate of 5 to 10 ° C./min in vacuum and reaching 15 to 30 at a temperature of 850 ° C.
After maintaining the temperature for a minute, then replacing the atmosphere with N ₂ gas and cooling, the base plate 24 is taken out from the furnace to room temperature. By this heat treatment, the ceramic chip 2 is attached to the bottom surface of the tappet body 21a.
2 is brazed.

[0014]

As described above, according to the present invention, one or more weights are loaded on the fixing tool which is inserted and fixed in the rocker arm insertion hole of the tappet body, so that it is mounted on the upper portion of the tappet body. Since the load is applied, it is possible to easily change the load applied to the upper portion of the tappet body by increasing or decreasing the weight loaded on the fixture. As a result,
It is possible to easily adjust the pressure applied to the ceramic chip of the tappet body during the heat treatment, and it is possible to improve the productivity in the production of various small quantities. Also, by forming a recess in the base plate that can hold the ceramic chip and the bottom of the tappet body that is placed so that the bottom overlaps the ceramic chip, and fix the ceramic chip and the bottom concentrically and securely. Can be brazed to. Further, a shaft portion that matches the shaft center of the tappet body is formed in the center of the fixture, and a weight having a hole or groove that can be fitted into the shaft portion is inserted into the fixture to load the weight into the fixture. The heat treatment can be carried out in a stable state by fitting it into the portion, and the entire bottom surface of the tappet body can be uniformly loaded by forming the shaft portion so as to coincide with the axis of the tappet body.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a brazing state of the present invention.

FIG. 2 is a vertical cross-sectional view showing the structure of the tappet.

FIG. 3 is an exploded perspective view of the tappet.

FIG. 4 is a structural diagram showing an OHV using a tappet.

[Explanation of symbols]

 21 Tappet 21a Tappet Main Body 21b Bottom 21c Rocker Arm Insertion Hole 22 Ceramic Chip 23 Brazing Material 24 Base Plate 24a Recess 26 Fixing Tool 26b Shaft 27 Weight Weight 27a Hole

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[Procedure amendment]

[Submission date] March 22, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006]

The invention according to claim 1 is
As shown in FIG. 1, the ceramic chip 22 is arranged on a base plate 24 having a peeling property with respect to the brazing material 23, and the tappet body 21 a is placed on the ceramic chip 22 via the brazing material 23.
Of the tappet body 21a so that the bottom surface 21b of the tappet body overlaps, a load is applied to the upper portion of the tappet body 21a, and heat treatment is performed in this state to braze the ceramic chip 22 to the bottom surface 21b of the tappet body 21a. Is. Its characteristic structure is that the tappet body 21a
There is to apply a load to the top of the tappet body 21a by the stacking Pusshuro head 1 into the insertion fixture 26 inserted to be fixed in the holes 21c or more of the weight 27. By increasing or decreasing the weight 27 loaded on the fixture 26, the load applied to the upper portion of the tappet body 21a can be easily changed.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

The characteristic structure of the present invention is that the tappet body 2 is used.
The weight is applied to the upper portion of the tappet main body 21a by loading one or more weights 27 on a fixture 26 fixed by being inserted into the push rod insertion hole 21c of 1a. Base plate 2 on which the ceramic chip 22 is arranged
The recess 24a of No. 4 has a depth capable of accommodating the ceramic chip 22 and the bottom portion of the tappet body 21a placed on the ceramic chip 22 so that the bottom surface 21b overlaps, and is slightly smaller than the outer diameters of the ceramic chip 22 and the bottom surface 21b. Is formed to a large size. Therefore, the ceramic chip 22 and the tappet main body 21a on which the bottom surface 21b is overlapped are fixed concentrically in an overlapping state. A columnar insertion portion 26a to be inserted into the push rod insertion hole 21c of the tappet body 21a is formed in the lower portion of the fixture 26,
The insertion portion 26a has a diameter slightly smaller than the hole 21c. Further, the tappet body 2 is provided at the center of the upper portion of the fixture 26.
A shaft portion 26b that coincides with the shaft center of 1a is formed, and a weight 27 is fitted into this shaft portion 26b.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

A predetermined pressure is applied using the fixture 26. That is, the insertion portion 26a provided at the bottom of the fixture 26
The hole 21 for inserting the push rod of the tappet body 21a
The fixture 26 is inserted into the tappet main body 21
a. Next, a weight 2 is attached to the shaft portion 26b of the fixture 26.
Insert 7 as many as necessary. The joining pressure between the ceramic chip 22 and the bottom surface 21b is adjusted by increasing or decreasing the number of weights 27. Next, the tappet body 21a and the ceramic chip 2 in the pressurized state shown in FIG.
2 is moved into the heat treatment furnace together with the base plate 24 to perform heat treatment. First, heat treatment is performed in vacuum at room temperature from 5 to 10 ° C /
When the temperature rises at a rate of minutes and reaches 850 ° C, 15 to 3
After maintaining the temperature for 0 minutes and then replacing the atmosphere with N ₂ gas and cooling, the base plate 24 is taken out from the furnace to room temperature. By this heat treatment, the ceramic chip 22 is brazed to the bottom surface of the tappet body 21a.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014]

As described above, according to the present invention, according to the present invention, the upper portion of the tappet body by stacking one or more of the weight in a fixture which is fixed by inserting the Pusshi Yuroddo insertion hole of the tappet body Since the load is applied to, the load applied to the upper portion of the tappet body can be easily changed by increasing or decreasing the weight loaded on the fixture. As a result, it is possible to easily adjust the pressure applied to the ceramic chip of the tappet body during the heat treatment, and it is possible to improve the productivity in the production of various small quantities. Also, by forming a recess in the base plate that can hold the ceramic chip and the bottom of the tappet body that is placed so that the bottom overlaps the ceramic chip, and fix the ceramic chip and the bottom concentrically and securely. Can be brazed to. Further, a shaft portion that matches the shaft center of the tappet body is formed in the center of the fixture, and a weight having a hole or groove that can be fitted into the shaft portion is inserted into the fixture to load the weight into the fixture. The heat treatment can be carried out in a stable state by fitting it into the portion, and the entire bottom surface of the tappet body can be uniformly loaded by forming the shaft portion so as to coincide with the axis of the tappet body.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] Explanation of sign

[Correction method] Change

[Correction contents]

[Explanation of symbols] 21 tappet 21a tappet body 21b bottom surface 21c push rod insertion hole 22 ceramic chip 23 brazing material 24 base plate 24a recess 26 fixture 26b shaft 27 weight 27a hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masayoshi Ohno, Mayor of Sodegaura, Chiba Prefecture, No. 2 580-99, Kasaya Seiko Co., Ltd. Within Automotive Industry Co., Ltd.

Claims (3)

[Claims] 1. A base plate (2) which is peelable from the brazing material (23).
4) A ceramic chip (22) is placed on the ceramic chip (22) and the tappet body (2) is placed on the ceramic chip (22) through the brazing material (23).
The tappet body (21a) so that the bottom surface (21b) of 1a) overlaps.
Place a load on the top of the tappet body (21a),
In this state, heat-treat and heat the bottom of the tappet body (21a).
In the method for manufacturing a tappet in which the ceramic chip (22) is brazed to (21b), 1 or 2 is attached to a fixture (26) fixed by being inserted into a rocker arm insertion hole (21c) of the tappet body (21a). More weight (2
A method for manufacturing a tappet, characterized in that a load is applied to an upper portion of the tappet body (21a) by loading 7). 2. A recess which can accommodate a ceramic chip (22) and a bottom portion (21b) of a tappet body (21a) placed on the ceramic chip so that a bottom surface (21b) is overlapped and fixed in the overlapped state (21). The method for producing a tappet according to claim 1, wherein 24a) is formed on the base plate (24). 3. The tappet body (21a) at the center of the fixture (26).
A shaft portion (26b) that coincides with the shaft center of is formed, and the shaft portion (26b)
The method for manufacturing a tappet according to claim 1 or 2, wherein a weight (27) having a hole (27a) or a groove that can be inserted into the shaft is inserted into the shaft portion (26b) to be loaded on the fixture (26). .