JPH06279136A - Joined body ceramic member with metallic member and production thereof - Google Patents

Abstract

PURPOSE:To obtain high-precision outside dimension by easy working and to prevent the damage in the vicinity of the outer circumferential edge of a joint part large in strain in a ceramic part. CONSTITUTION:In a joined body 1 made by joining a ceramic member 2 with a metallic member 3 with a brazing filler metal 4, a metallic annular body 5 is fitted to an outer circumferential face including the outer circumferential edge of the joint face 2a, 3a. Since the annular body 5 is metallic, the outer circumferential face is easily finished and the annular body 5 is also a protective member of the ceramic member 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an engine tappet,
The present invention relates to a joined body (hereinafter, also simply referred to as a joined body) of a ceramic member and a metal member used for a valve lifter, a rocker arm, or the like, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Ceramics are used in various fields because they have excellent properties such as heat resistance, thermal shock strength, mechanical strength at high temperature, and wear resistance. However, it is rarely used alone and is often used as a bonded body formed by brazing with a metal member. As a basic structure, for example, there is a cylindrical one formed by joining a disk-shaped ceramic member and a cylindrical metal member. Based on this structure, it is applied to various parts such as engine tappets. Has been done.

By the way, in this kind of joined body, in order to push out blowholes and impurities in the brazing material to obtain a highly reliable joint, the joining surface is loaded with a larger amount of brazing material than necessary ( Intervened). Therefore, in the process of pressurizing the joint surfaces and heating and brazing them, the excess brazing material will stick out from the outer peripheral edge of the joint surface. Further, in the process of brazing, since positioning in the radial direction (centering) on the joint surface is also important for accuracy, conventionally, as shown in FIG. 4, the inner diameter is smaller than the outer diameter of the joined body 41 to be joined. A large ring (cylindrical) positioning jig J is used to insert a ceramic member 42 and a metal member 43 inside of which a predetermined brazing material 44 is interposed between the joint end faces to regulate the radial deviation. However, after brazing, it is removed. Here, the positioning jig J is generally made of graphite although it is expensive. This product is not only excellent in workability, but also has a thermal expansion coefficient similar to that of ceramics.
This is because it is a suitable material.

[0004]

The brazing of the ceramic member and the metal member is carried out at a high temperature of about 800 ° C. to 900 ° C. or higher, but the ceramic is made of Si3 Ni4, SiC,
It has a smaller coefficient of thermal expansion than general metals such as Al2 O3. Therefore, when positioning and heating with the jig J as described above, a relatively large gap is formed between the inner surface of the jig J and the outer surface of the ceramic member 42, and excess brazing material flows into this gap. On the other hand, recently, an active metal (In-Cu-
A method of using Ag—Ti based brazing material or the like as an active brazing material and joining without metallization has been widely adopted. In this case, the excess brazing material that has flowed out from the joint surface is the jig J.
As a result, the jig can usually be used only once, which increases the manufacturing cost. In addition, even if it does not react, it will be worn and damaged by repeated use and its life will be shortened in a short time.
Was treated as a consumable item.

In addition, when joining by active brazing, when the wettability of the metal member is worse than that of ceramic, the brazing material flowing out is ceramic in the form as shown in FIG. 4 (enlarged view). In some cases, the ceramics crawled up in the form of balls 44a on the side, and stress concentration occurred on the ceramic at that portion during the solidification process, resulting in damage. On the other hand, the adhesion of the balls 44a of the brazing material is one of the poor appearances even if it is not damaged, and must be removed by polishing in the next step.

Further, in this kind of bonded body 41 thus obtained, which requires high precision, it is necessary to polish the outer periphery, but it is extremely difficult to process the ceramic part. Moreover, during the handling process, brittle ceramics are susceptible to breakage, and in particular near the periphery of the brazing part, considerable strain due to the difference in thermal expansion coefficient remains, resulting in many breakages. This has been a factor in lowering the yield. An object of the present invention is to solve these problems at once.

[0007]

In order to achieve the above object, the present invention provides a ceramic member and a metal member which are joined together by a brazing material, wherein an outer peripheral surface including an outer peripheral edge of the joint surface is formed. In contrast, a metal annular body is fitted. As this manufacturing method, both end faces of both members to be joined are abutted with a brazing material interposed, and a metal annular body is fitted to the outer peripheral surface including the outer peripheral edges of the abutted end faces. It is good to heat and braze under it. In this case, it is efficient to use active brazing material for the brazing material because the ceramic member does not need to be metallized.

[0008]

In the joined body according to the present invention, since the metal annular body (hereinafter, also simply referred to as an annular body) is fitted on the outer periphery of the joined body, the outer diameter at that portion can be easily processed. it can. Further, the ceramic portion near the outer peripheral edge of the joint surface having a large strain is covered with the annular body, and plays a protective function in the handling process. Furthermore, in the manufacturing method according to the present invention, the relatively inexpensive metal annular body functions to position the joint surface in the radial direction. Therefore, a special jig unlike the conventional one is not required, and the manufacturing cost can be reduced accordingly. Moreover, when active brazing is used, excess brazing material that has run off also wets the inner surface of the annular body, so that ball-shaped adhesion to the ceramic side is prevented without impairing the merit of using active brazing. .

[0009]

Embodiments of the present invention will be described in detail with reference to FIG. However, the bonded body 1 in this example
Is composed of the following four components. That is, the ceramic member 2 is made of silicon nitride (90 wt% Si
3 N4, balance sintering aid) Sintered body, a disk having a diameter of 30 mm and a thickness of 3 mm, both end surfaces of which are ground and finished. On the other hand, the metal member 3 is JIS SNCM630,
It is processed into a diameter of 30 mm and a length of 50 mm.
In addition, the brazing material 4 is an In—Ti—Cu—Ag-based (In;
12.5%, Ti; 1.5%, Cu; 27%, Ag; 6
0%) active brazing material. And the metal annular body 5
Is made of SPCC (cold rolled steel) and has a thickness of 0.4 mm,
It is a thin short cylindrical ring having an inner diameter of 30.1 mm and a height of 6 mm. The constituent material of the bonded body in the present invention may be an appropriate material depending on the application of the bonded body.

This manufacturing method is as follows. First, the annular body 5 is externally fitted to the outer periphery of the ceramic member 2 to form a joint surface (end surface).
The brazing material 4 is concentrically interposed in 2a. Next, the metal member 3 is fitted into the inner circumference of the annular body 5, and the ceramic member 2 and the metal member 3 are butted against each other under appropriate pressure via the joint surfaces 2a and 3a. Then, under this condition, the temperature is maintained in vacuum at 800 ° C. for 30 minutes to perform N 2 gas displacement cooling. In this brazing process, while the annular body 5 acts as a positioning jig, the surplus excess brazing material 4a protruding from the annular body 5 wets the inner surface of the annular body 5, and therefore the ball-shaped adhesion to the ceramic side does not occur. Go through the entire gap.

In this example, however, the joining surface 2 can be formed without using an expensive positioning jig as in the prior art.
It is possible to obtain a substantially columnar joined body 1 in which the annular body 5 is fitted to the outer peripheral surface including the outer peripheral edges of a and 3a. In this example, not only the vicinity of the outer peripheral edges of the joint surfaces 2a and 3a having a large residual strain but also the entire outer periphery of the ceramic member 2 is not exposed, so that the handling is extremely simple. If necessary, the outer peripheral surface of the annular body 5 may be finished by turning or cutting, but since it is made of metal, it can be finished easily and highly accurately.

In the present invention, the metallic ring-shaped body is
If the strength is too large relative to the ceramic member due to being thick, etc., the brazing material or the annular body that has flowed into the gap between the ceramic member and the annular body during the heating and cooling process may be caused by the difference in thermal expansion. It will cause the ceramic member to be strongly tightened, which may result in damage. On the other hand, if it is too thin or its strength is reduced, the annular body itself may be damaged. Therefore, in consideration of these points, it is necessary to design the wall thickness according to the material and size of the ceramic member, the material and strength of the annular body itself, the gap between the outer diameter of the ceramic member and the like. By the way, in the above embodiment, the wall thickness is 0.05 to 2 mm.
In the range of 0.1 mm, a bonded body was prepared by using the samples changed by 0.1 mm, but no such problem was found.

Further, the annular body is preferably selected from a metal having a better wettability for the brazing material than the metal member to be joined. This is because the surplus brazing material that flows out into the gap wets the inner surface of the annular body well, and therefore adheres more evenly to the inner surface of the annular body. However, the outer periphery of the ceramic member and the brazing material may not necessarily be physically joined. Note that examples of the material of the annular body include S40C, SCM435, copper plate, kovar, 42alloy (Fe-Ni alloy), and the like, and an appropriate material may be selected and used according to the material of the joined body, application, and the like. . In particular, iron is very suitable for mass production because the wettability of the active wax is extremely good and the cost is low. If the annular body is tubular, it can be easily manufactured by press punching a thin plate or welding. Further, in the above embodiment, the annular body is a cylindrical shape, but in the present invention, it may be a shape corresponding to the shape of the joined body, and if it is a regular square pole, it is a square tubular shape inscribed therein. Become. Further, the cross-sectional shape may be any shape as long as it is in contact with the outer peripheral surface including at least the outer peripheral edge of the joint surface, and may be an L-shape or the like depending on the joint body.

On the other hand, the amount of the brazing material used is set to be slightly larger in consideration of the volume of the gap inside the annular body. Further, although the active brazing material is used in the above embodiment, the brazing material in the present invention is not limited to this. However, it is needless to say that the bonding surface of the ceramic member is preliminarily subjected to metallizing treatment by a method such as sputtering or vapor deposition when not using active solder.

Next, an embodiment in which the present invention is embodied as a tappet for an engine inserted between a cam and a push rod will be described with reference to FIG. Except for the difference that it is a tappet and that the metal member has a composite structure of a tappet body 22 and a cushioning member (copper plate) 23, it is basically the same as the previous example, so only the differences will be described. That is, in this example, between the bottom surface of the bottomed cylindrical tappet body 22, which is a metal member, and the buffer member (disk) 23, and between the buffer member 23 and the ceramic member (disk) 24. Each prescribed brazing material 25
And the stepped portion 2 at the lower outer peripheral edge of the tappet body 22
A cylindrical annular body 26 formed so as to cover the entire outer periphery of the ceramic member 24 from 2a is externally fitted and brazed, and the bottom surface of the tappet body 22 and the cushioning member 2 are formed.
3 and the respective bonding surfaces of the ceramic member 24, and further, their outer circumference and the inner circumferential surface of the annular body 26 are brazed. As can be seen from this example, the metal member of the present invention may be a single member or a composite structure in which two or more metal members are joined.

Thus, while the sliding surface 24a, which becomes the contact surface with the cam and whose wear resistance is important, is made use of the characteristics of ceramics, the outer periphery thereof is covered with metal, which may cause chipping or the like during the handling process. Is effective in preventing the occurrence of In addition, in this example, the cross section of the annular body 26 is substantially L-shaped with the flange 26a protruding outward. Accordingly, since the flange 26a is provided, the strength of the annular body 26 itself in the radial direction is large and the shape holding performance is good.
To that extent, handling and inventory management become easier. Moreover, even if the outer circumference of the flange 26a projects from the outer circumference of the tappet body 22 due to a dimensional error, that portion can be easily cut and removed.

FIG. 3 shows an embodiment in which the joined body 31 is embodied in another engine tappet. The previous example is that there is no buffer member and the flange 36a of the annular body 36.
The difference is that it is a modification of the previous example, except that the section is reversely bent inward in the cross section to form a "V" shape, and only the difference will be described. That is, in this example, the tappet is mushroom-shaped, and the inner surface of the annular flange 36a is brought into contact with the outer peripheral corners of the expanded diameter portion 32a at the bottom of the tappet body 32, and the brazing material 35 is interposed. The ceramic member 34 is positioned so as to be inserted into the annular body 36, and both are brazed. In addition,
The structure of the joined body according to the present invention can be applied to various members other than these tappets.

[0018]

As is apparent from the above description, in the joined body according to the present invention, since the metal annular body is fitted on the outer periphery of the joined body, a highly accurate outer diameter can be obtained by simple working. Obtainable. Moreover, since the portion of the ceramic member near the outer peripheral edge of the joint surface with large strain is covered with the annular body and is not exposed, it is effective in preventing damage during the handling process, and the defect rate can be reduced.

Further, according to the method for manufacturing a joined body according to the present invention, a relatively inexpensive metal annular body is used for radial positioning of the joint surface without requiring an expensive positioning jig as in the prior art. Therefore, the manufacturing cost can be reduced. In this case, when using active low,
Excessive excess brazing material wets the inner surface of the annular body, preventing ball-shaped adhesion to the ceramic member side without impairing the merit of active brazing, and thus less damage prevention and product yield. improves.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a joined body according to the present invention.

2A and 2B are a partially broken cross-sectional view and an enlarged cross-sectional view of a main part of the joined body of the present invention embodied in an engine tappet.

FIG. 3 is a partial cutaway cross-sectional view of a joined body of the present invention embodied in another engine tappet.

FIG. 4 is a cross-sectional view illustrating a conventional bonded body and a manufacturing process thereof, and an enlarged view of a main part thereof.

[Explanation of symbols]

 1, 21, 31 Joined body 2, 24, 34 Ceramic member 2a, 3a Joining surface 3 Metal member 4, 25, 35 Brazing material 5, 26, 36 Metal annular body 22, 32 Tappet body (metal member) 23 Cushion Material (metal material)

Claims (3)

[Claims] 1. A structure in which a ceramic member and a metal member are joined by a brazing material, wherein a metal annular body is fitted to an outer peripheral surface including an outer peripheral edge of the joint surface. And a joined body of a ceramic member and a metal member. 2. A method for producing a joined body by brazing and joining a ceramic member and a metal member, wherein both end faces of both members to be joined are butted against each other with a brazing material interposed and the both ends are butted. Manufacturing of a joined body of a ceramic member and a metal member, characterized in that a metal annular body is fitted to an outer peripheral surface including an outer peripheral edge of the surface, and then heated and brazed under the outer peripheral surface. Method. 3. The method for producing a joined body of a ceramic member and a metal member according to claim 2, wherein the active material is used as the brazing material.