JP2000264747A - Ceramic sliding parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ceramic sliding parts having the excellent durability of joined parts of a ceramic body and a metallic body by the control of the shapes or sizes of the chamfered parts to be formed on the ceramic body and the metallic body. SOLUTION: The ceramic sliding parts are composed as tappets and have the structure obtained by forming the rear surface side of the ceramic body 4 as a joining surface 4b and brazing and joining the same to the end face 2a of the metallic body 2. The front surface side of the ceramic body 4 is formed as a sliding surface 4a. The chamfered parts 4c and 4d are applied on the sliding surface 4a and likewise the respective outer peripheral edges of at least either of the joining surface 4b of the ceramic body and the end face 2a of the metallic body 2. The inner edge of the chamfered part 4c on the sliding surface side of the ceramic body exists on the side inner than at least either of the inner edge B of the chamfered part 4d on the joining surface side of the ceramic body and the inner edge C of the chamfered part 2c on the end face side of the metallic body. When a cam, etc., abut against these parts and the parts slide, the stress concentration to the outer peripheral part of the brazed and joined layer and eventually the plastic deformation, etc., thereof may be reduced and the durability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic sliding part suitable for a sliding part of a valve train such as a tappet, a valve bridge, a valve lifter and the like of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as the above sliding parts, those having a structure in which a sliding surface side is formed of a ceramic plate and which is joined to a metal body by brazing or the like are often used.
For example, chipping and chipping are liable to occur in a ceramic plate at the time of manufacture (or at the time of handling after manufacture), and in order to prevent this, it is indispensable to apply a certain amount of chamfering to the plate surface edge. In addition, the metal body to which the ceramic plate is bonded is not as severely chipped as the ceramic, but in most cases, the same chamfer is applied to the peripheral edge of the bonding end face to protect the corners.

[0003] However, the above chamfering is performed, for example, by butt brazing a ceramic disk provided with chamfers on both sides of a sliding surface and a joining surface of a ceramic plate and a metal body having a chamfer on the joining surface side. In the case of such a structure, a kind of groove-shaped notch is formed in the outer peripheral portion of the joint. Therefore, for example, if stress is concentrated on the outer peripheral portion of the ceramic plate due to sliding of the cam or the like, cracks or peeling from the joint interface may easily occur due to deformation of the outer peripheral portion of the soft brazing material layer.

An object of the present invention is to provide a ceramic sliding component having excellent durability at a joint between a ceramic body and a metal body by controlling the shape or size of a chamfered portion applied to the ceramic body or the metal body. It is in.

[0005]

[Means for Solving the Problems and Functions / Effects] In the case of a joint type ceramic sliding component, the adhesion of the ceramic body is improved, the deflection of the ceramic body surface after brazing is suppressed, and the flatness and parallelism are further improved. Very often, both sides of the fired ceramic body are ground to adjust the surface roughness. Here, since the ceramic body tends to be particularly chipped at the edges and the like at the stage of the unfired powder molded body, it is general to chamfer the outer edge of the surface at the molding stage. In this case, at the time of firing, although the amount of chamfering generated in each ceramic disk was substantially equal, the width of the chamfered portion also changed due to the difference in the amount of grinding, and the size became large. For example, when chamfering both surfaces of a ceramic body, a difference may occur in the chamfer width of both surfaces due to a difference in the amount of grinding. All of these appear as variations in the inner edge positions of the chamfered portions of the finally obtained joined body. In addition, a deviation between the ceramic body and the metal body generated at the time of joining also greatly affects the variation in the inner edge position of the chamfer.

The inventors of the present invention have conducted intensive studies in view of the above situation, and as a result, have found that a notch structure on the outer periphery due to a chamfered portion is formed at the peripheral edge of the joint between the ceramic body and the metal body. In this case, the inventors have found that the positional relationship between the inner edges of the chamfered portions formed on the ceramic body and the metal body greatly affects the durability of the joined body, and have completed the present invention.

That is, a first configuration of the ceramic component of the present invention has a structure in which the back surface of a ceramic body is used as a bonding surface and this is joined to an end surface of a metal body by brazing. In a ceramic sliding component having a sliding surface, a chamfered portion is formed on each outer peripheral edge of the sliding surface of the ceramic body and at least one of the joining surface of the ceramic body and the end face of the metal body. The inner edge of the moving surface chamfer is located inside the inner edge of the ceramic body joining chamfer and / or the inner edge of the metal body chamfer.

[0008] If a chamfer is formed on each outer peripheral edge of at least one of the joining surface of the ceramic body and the end face of the metal body,
A circumferential notch structure as described above is generated at the joining peripheral portion. However, as in the first configuration of the ceramic component of the present invention, the inner edge of the ceramic body sliding surface chamfered portion,
By adjusting the position of each inner edge so that it is located inside at least one of the inner edge of the ceramic body joint chamfer and the inner edge of the metal body chamfer, for example, a cam or the like comes into contact and slides. When it moves, the stress concentration on the outer peripheral portion of the brazing joint layer, and the plastic deformation thereof can be dramatically reduced, and a ceramic component with improved durability can be realized.

In the first configuration of the ceramic component, the width of the chamfer on the sliding surface of the ceramic body is set to 0.5 to 1.
It is desirable to adjust to a range of 5 mm. If the width of the chamfered portion is less than 0.5 mm, the effect of reducing stress concentration on the outer peripheral portion of the brazing joint layer and eventually the plastic deformation or the like becomes insufficient, which may lead to a decrease in the fatigue resistance of the joint portion. On the other hand, a chamfered portion exceeding 1.5 mm in width causes unnecessary thinning of the outer edge of the ceramic body, and the strength of the outer edge of the ceramic body itself is insufficient, causing defects such as chipping, wear resistance or fatigue resistance. It may lead to a decrease. It is desirable to adjust the width of the chamfered portion more desirably in the range of 0.5 to 1.0 mm. In the present specification, the width of the chamfered portion is defined as a distance between an inner edge and an outer edge when the chamfered portion is projected on the reference surface when a reference surface orthogonal to a joining direction of the ceramic body and the metal body is considered. (For example, when the joining surface between the ceramic body and the metal body is formed in a circular shape, the width of the annular chamfer formed on the periphery thereof means the chamfering portion width dimension in the joining surface radial direction) .

On the other hand, a second structure of the ceramic component of the present invention has a structure in which the back surface of the ceramic body is used as a bonding surface and this is brazed to the end surface of the metal body. In a ceramic sliding component having a sliding surface, a chamfered portion is formed on an outer peripheral edge of a sliding surface of a ceramic body, and a brazing joint is formed in which an outer peripheral surface of the ceramic body and a metal body are formed therebetween. It is characterized in that it is surface-finished so as to be substantially flush with the layer, and the width of the chamfer on the sliding surface of the ceramic body is adjusted in the range of 0.3 to 1.5 mm.

The outer peripheral surfaces of the ceramic body and the metal body are surface-finished by, for example, outer peripheral polishing or outer peripheral cutting so as to be substantially flush with the brazing joint layer formed therebetween. Unlike the first configuration, substantially no circumferential notch structure as described above occurs at the joining peripheral portion. And, assuming this, by adjusting the width of the chamfer of the sliding surface of the ceramic body in the range of 0.3 to 1.5 mm, when the cam or the like abuts and slides,
Stress concentration on the outer peripheral portion of the brazing joint layer, and plastic deformation thereof can be dramatically reduced, and a ceramic component with improved durability can be realized.

In the second configuration, when the width of the chamfered portion is less than 0.3 mm, the effect of reducing the concentration of stress on the outer peripheral portion of the brazing joint layer, and the effect of reducing the plastic deformation, becomes insufficient, and the fatigue resistance of the joint portion is reduced. This may lead to a decrease in strength and the like. On the other hand, a chamfered portion exceeding 1.5 mm in width causes unnecessary thinning of the outer edge of the ceramic body, and the strength of the outer edge of the ceramic body itself is insufficient, causing defects such as chipping, wear resistance or fatigue resistance. It may lead to a decrease. It is desirable to adjust the width of the chamfered portion more desirably in the range of 0.5 to 1.0 mm.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overhead valve mechanism using a tappet as a ceramic sliding component of the present invention. The tappet 1 and the push rod 103 move up and down by the rotation of the cam 100, and open and close the valve 101 via the rocker arm 102. FIG.
Is an enlarged view of the tappet 1. FIG. In the tappet 1, a metal body (hereinafter, also referred to as tappet fitting) 2 and a ceramic body (hereinafter, also referred to as ceramic plate) 4 are joined via a brazing material layer 3, which is a main part of a brazing joining layer. It has a structure. The tappet fitting 2 is made of an iron-based material, and has an axial push rod insertion hole 1c at one end side of the main body 1a having a circular cross section, and the main body 1a at the other end. Also has a shape in which the large-diameter sliding base portion 1b is integrally formed. On the other hand, the ceramic plate 4 is formed in a disc shape as a sintered body of silicon nitride, and is overlapped and joined to the flat end surface of the sliding base 1b. The brazing material forming the brazing material layer 3 is a Cu-based or Ag-based brazing material.
The end face of the ceramic plate 4 opposite to the side in contact with the brazing material layer 3 is a sliding surface 4 a with the cam 100.

The sliding surface 4a of the ceramic plate 4 is crowned (small curvature protruding at the center) as shown in the drawing in a slightly exaggerated manner. This crowning
When the metal body 2 and the ceramic plate 4 are brazed and cooled, the ceramic plate 4 is elastically deformed so that the center portion rises by utilizing the fact that the metal body 2 contracts more than the ceramic plate 4. It is formed by the thing.

Next, as shown in FIG. 3A, at least one of the sliding surface 4a of the ceramic plate 4 and the joining surface 4b of the ceramic plate 4 and the end surface 2a of the metal body 2 (both in this embodiment). Chamfers 4c, 4d, 2
c is performed. By applying the chamfered portions 4c, 4d, and 2c in this manner, the outer peripheral exposed surface of the brazing material layer 3 is used as a bottom surface at the joining peripheral portion between the ceramic plate 4 and the metal body 2, and the chamfered portions 4d and 2c are formed inside. A notch 1a in the circumferential direction having a substantially C-shaped cross section is formed as a side surface. In the tappet 1 described above, the inner edge of the ceramic body sliding surface chamfered portion 4c is formed by the inner edge of the ceramic body joining surface chamfered portion 4d and the metal body end surface chamfered portion 2c.
With respect to at least one of the inner edges of c, in the embodiment, both inner edges of the double-sided portions 4d and 2c are located inside the entire periphery (first configuration).

The operation and effect of adopting such a configuration will be described below. Factors greatly affecting the durability of the tappet 1 include how the cam 100 hits the outer periphery of the sliding surface 4a of the tappet 1 (for example, the cam sliding range and the contact angle of the cam surface with the tappet). For example, the dimensional accuracy of the block hole on the engine side or the cam 1
In the case where the cam 100 comes into contact with the outermost periphery of the sliding surface 4a due to the processing accuracy of 00 (for example, the forming accuracy of the cam taper and the cam width) or the mounting accuracy of the tappet, the joining including the brazing material layer 3 is performed. Great damage to the part.

For example, the tappet 1 is rotated as the cam 100 slides by using crowning of the sliding surface 4a to prevent uneven wear of the sliding surface 4a. Cam 1
00 is for this purpose, as shown in FIGS. 7 (a) and 7 (b), with respect to the rotation axis O1 of the tappet 1,
The cam taper is eccentric (offset) so that the center line O2 in the width direction of the cam 100 is shifted toward one side, and the cam taper is lowered from the outer edge of the sliding surface 4a of the tappet 1 toward the rotation axis O1 in the width direction of the outer peripheral surface of the cam 100. (Note that the cam sliding range on the sliding surface 4a is indicated by a hatched area in the drawing). At this time, the cam 100
When the rotation is low, the impact force applied to the ceramic plate 4 from the cam 100 as shown by the broken line in FIG.
It becomes maximum near the center of the sliding surface 4a, which is the peak of crowning (ie, near the center of mass of the tappet 1). However, in the high-speed rotation state, an extremely large impact force is applied to the vicinity of the outer peripheral edge of the sliding surface 4a as shown by a solid line in the drawing due to the inertia force of the valve train and the above-described manner of providing the cam taper. It takes shape.

At this time, each of the chamfered portions 4c and 4c shown in FIG.
The inner edge positions of 4d and 2c (indicated by A, B and C in the figure) greatly affect the fatigue resistance of the joint by the brazing material layer 4.
That is, as shown in FIG. 3 (c), the inner edge A of the ceramic body sliding surface chamfered portion 4c is formed by the metal body end surface chamfered portion 2c.
When it is outside the inner edge C of c, the impact force applied from the cam 100 via the ceramic plate 4 becomes large, and the plastic strain generated in the brazing material layer 3 becomes large, so that the durability may be remarkably reduced.

However, as described above, the inner edge A of the ceramic body sliding surface chamfer 4c is positioned inside the inner edge B of the ceramic body joining surface chamfer 4d or the inner edge C of the metal body end surface chamfer 2c. By adjusting the positions of the inner edges A to C so as to position them, the concentration of stress on the outer peripheral portion of the brazing layer 4 and, consequently, the plastic deformation thereof can be drastically reduced, and the fatigue resistance performance of the joint is greatly reduced. Can be improved.

The bonding surface 4b of the ceramic plate 4 and the metal body 2
When the chamfers 4d and 2c are formed on both outer peripheral edges of the end face 2a of the ceramic body, as shown in FIG. 3B, the inner edge A of the ceramic body sliding surface chamfer 4c is Only one of the inner edge B of the chamfered portion 4d and the inner edge C of the metal body end face chamfered portion 2c (in this case, only for C) may be located inside. This also has the effect of reducing the concentration of stress on the outer peripheral portion of the brazing layer 4 as compared with the embodiment of FIG. 3C in which the inner edge A is outside both the inner edges B and C. To enhance this effect, it is desirable that the inner edge A of the ceramic body sliding surface chamfered portion 4c be located inside the inner edge C of the metal body end surface chamfered portion 2c. Then, as shown in FIG.
If the aspect in which the inner edge A is present inside both the inner edges B and C is adopted, the above-mentioned effect becomes more remarkable.

When the chamfered portions 4d and 2c are formed on both the joining surface 4b and the end surface 2a, the gap between the ceramic plate 4 and the metal body 2 generated at the time of joining and the variation in the chamfer size (width) are taken into consideration. The present invention in which the inner edges A to C of the respective chamfered portions have the above-described positional relationship by joining the ceramic plate 4 in which the chamfered portion 4c on the sliding surface 4a side is larger than the chamfered portion 2c on the joining surface 4b side or the end surface 2a side. Can be manufactured. In addition, the chamfered portion 4c on the sliding surface 4a side (a position where the load from the cam tends to concentrate)
Is located inside the inner edge C of the chamfered portion 2c on the end surface 2a side of the metal body 2 which is relatively likely to be a starting point of joint deterioration, so that the shearing stress generated in the chamfered portion when the cam 100 abuts. Can be reduced.

As shown in FIG. 4, it is also possible to omit the chamfered surface of the ceramic body joining surface and to make the peripheral edge of the surface close to the pin angle. In this case, if the inner edge A of the ceramic body sliding surface chamfer 4c is located inside the entire periphery of the inner edge B of the metal body edge chamfer 2c, the inner edge A of the brazing layer 4 can be moved to the outer periphery. Can be drastically reduced. Further, since the ceramic body joint surface chamfer is not formed, it is also possible to simplify or omit the machining finish by grinding or the like on the joint surface side.

In the first configuration, the width x of the chamfered portion 4c on the sliding surface of the ceramic body is 0.5-1.
It is adjusted within a range of 5 mm, preferably 0.5 to 1.0 mm. Further, as shown in FIG. 4, when only one of the ceramic body joining chamfer and the metal body end chamfer is formed (only the latter 2c in the figure), the inner edge of the chamfer is used as a reference chamfer. In the figure, C) is set, and when both of FIGS.
The inner edge A and the reference chamfered edge of the ceramic body sliding chamfered edge 2c are used as the reference chamfered edge of the inner edge (in the figure, the inner edge C of the chamfered portion 2c) outside the inner edge A. It is desirable that the distance δ between them is 0.1 mm or more. When the distance δ is less than 0.1 mm, the effect of reducing the stress concentration on the outer peripheral portion of the brazing layer 4 and thus the plastic deformation thereof becomes insufficient, and the improvement of the fatigue resistance of the joint cannot be expected. There are cases.

As shown in FIG. 5 (a), the tappet 1 has a chamfered portion 4c similarly formed on the outer peripheral edge of the sliding surface of the ceramic plate 4, while the outer peripheral surface between the ceramic plate 4 and the metal body 2 is formed. However, the surface may be finished by polishing or the like so as to be substantially flush with the brazing material layer (brazing joining layer) 3 formed therebetween. The width of the ceramic body sliding surface chamfer 4c is adjusted in the range of 0.3 to 1.5 mm, preferably 0.5 to 1.0 mm.

According to this structure, the notch 1a at the peripheral edge of the joint as shown in FIGS. On the premise of this, the width x of the ceramic body sliding surface chamfered portion 4c is set to 0.3 to 1.5 mm, and the inner edge of the ceramic body sliding surface chamfered portion 4c is positioned from the outer periphery of the joint, which is the starting point of joint deterioration. By separating, the stress concentration on the outer peripheral portion of the brazing material layer 4 and the plastic deformation thereof can be greatly reduced, and the fatigue resistance of the joint can be greatly improved.

In this case, for example, both are joined by brazing in a state where a chamfered portion is also formed on the joining surface side of the ceramic plate 4 or the end surface side of the metal body 2, for example, the chamfered portion on the joining surface side disappears almost completely. Is performed until the outer peripheral surfaces of the ceramic plate 4, the metal body 2, and the brazing material layer 3 are substantially flush with each other. As a result, as shown in FIG. 5A, the outer peripheral surface on the joining surface side of the ceramic plate 4 and the metal body 2 is
It is almost in a pin angle state. As shown in FIG. 5B, the chamfered portion 4d or 2c partially remains on the joining surface side of the ceramic plate 4 or on the end surface side of the metal body 2.
The outer peripheral surface may be finished evenly, but from the viewpoint of suppressing stress concentration on the outer peripheral portion of the brazing material layer 4, the embodiment of FIG. 5A can be said to be more advantageous.

In FIGS. 3 to 5, a reference plane BP perpendicular to the joining direction of the ceramic plate (ceramic body) 4 and the metal body 2 (in this case, the direction of the rotation axis O1 of the tappet 1) is shown in FIG. The angle θ between the sliding surface and the chamfer 4c is preferably adjusted in the range of 20 ° to 50 °. When the angle θ is less than 20 °, not only the effect of preventing chipping and the like is insufficient, but also the effect of suppressing stress concentration on the outer peripheral portion of the brazing material layer 4 may be insufficient. Also, 50 °
Is exceeded, the chamfered portion width x tends to be insufficient, and the effect of suppressing stress concentration on the outer peripheral portion of the brazing material layer 4 may be insufficient. The angle θ is more desirably 25 ° to 4 °.
It is preferable to adjust the angle within a range of 5 °.

As shown in FIG. 8, a point on the peripheral surface of the cam 100 which is located on the side opposite to the nose top with respect to the rotation axis O3 is a cam bottom point, and the cam bottom point is the sliding surface 4a.
Tangent plane AP at the cam bottom point when touching
Similarly, the tangent plane CP at the start point of the cam nose portion on the peripheral surface (the point at which the outline of the cam nose portion starts to deviate from the cam base circle) is in contact with the sliding surface 4a.
Is defined as an angle φ per cam, an angle θ between a reference surface orthogonal to the joining direction of the ceramic body and the metal body and the chamfered portion of the ceramic body sliding surface is φ−10.
It is more preferable that the angle is adjusted to be equal to or more than φ and equal to or less than φ + 10 ° in order to enhance the effect of suppressing the concentration of stress on the outer peripheral portion of the brazing material layer 4.

The Fe-based material constituting the metal body 2 includes
Various types of carbon steel, alloy steel (including stainless steel or heat-resistant steel), or cast iron can be used. For example, according to JIS, the following can be exemplified (composition unit is% by weight). (1) Ni-Cr-Mo steel for machine structure: SNCM630
(C: 0.25 to 0.35, Si: 0.15 to 0.3
5, Mn: 0.35 to 0.60, Ni: 2.5 to 3.
5, Cr: 2.5 to 3.5, Mo: 0.5 to 0.7, residual Fe (unit: wt%, the same applies hereinafter)), SNCM439
(C: 0.36-0.43, Si: 0.15-0.3
5, Mn: 0.6 to 0.90, Ni: 1.6 to 2.0,
Cr: 0.6 to 1.0, Mo: 0.15 to 0.3, residual F
e), SNCM447 (C: 0.44-0.50, S
i: 0.15 to 0.35, Mn: 0.6 to 0.90, N
i: 1.6 to 2.0, Cr: 0.6 to 1.0, Mo:
0.15 to 0.3, residual Fe) and the like. (2) Cr-Mo steel for machine structure: SCM445 (C: 0.
43 to 0.48, Si: 0.15 to 0.35, Mn:
0.6-0.85, Cr: 0.9-1.2, Mo: 0.
15-0.3, residual Fe) and the like. (3) Cr steel for machine structure: SCr440 (C: 0.43 ~
0.48, Si: 0.15 to 0.35, Mn: 0.6 to
0.85, Cr: 0.9-1.2, residual Fe), SCr4
15 (C: 0.13-0.18, Mn: 0.60-0.
85, Cr: 0.90 to 1.20, residual Fe (unit:% by weight)) and the like. (4) Carbon steel for machine structure: S50C (C: 0.47-0.
53, Mn: 0.6-0.9, residual Fe) and the like.

The ceramic body 4 can be mainly composed of silicon nitride as described above. Silicon nitride has excellent mechanical strength, abrasion resistance, and corrosion resistance. Sufficient strength and durability even for valve train sliding parts used in high-temperature, high-load and corrosive harsh environments such as tappets. It is possible to secure the property. In addition, except for silicon nitride,
Sialon, silicon carbide, aluminum nitride and the like can also be used.

As a brazing material for forming the brazing material layer 3, an Ag-based brazing material containing Ag as a main component can be used. Ag-based brazing filler metals usable in the present invention include Ag
-Cu-Ti-based brazing material (Cu: 33.0 to 37.5 (for example, 35.25), Ti: 1.0 to 2.5 (for example, 1.
75), balance Ag (unit:% by weight, the same applies hereinafter)), Cu
-Al-Si-Ti brazing material (Al: 1.0 to 3.0)
(For example, 2.0), Si: 2.0 to 4.0 (for example, 3.
0), Ti: 1.0 to 3.5 (e.g., 2.25), balance Cu), Ag-Cu-In-Ti-based brazing material (Cu: 2)
5.0 to 29.5 (for example, 27.25), In: 10 to 10
15 (e.g., 12.5), Ti: 0.5 to 2.0 (e.g., 1.25), and the balance is Ag. When the Ag-based brazing material is used, the thickness of the brazing material layer is preferably adjusted in the range of 10 to 50 μm in order to sufficiently achieve the effects of the present invention.

On the other hand, when a Cu-based brazing material containing Cu as a main component is used, the heat resistance of the brazing material layer, and the high-temperature bonding strength of the joined body can be further increased. By using a Cu-based brazing material containing 80% by weight or more of Cu, a joined body particularly excellent in heat resistance of a joined portion can be obtained. As a Cu-based brazing material, specifically, Cu-
Al-Si-Ti-based brazing material can be used.
By setting the content of Cu to 80% by weight or more as described above, the heat resistance of the brazing material layer becomes particularly good. Al mainly serves to adjust the melting point of the brazing material, and the higher the content, the lower the melting point of the brazing material. On the other hand, Si enhances the flowability of the liquid phase formed by melting the brazing material, and contributes to the formation of a joint structure with few defects such as voids. However, if the Si content is less than 0.1% by weight, the effect of improving the fluidity of the liquid phase becomes poor, and if it exceeds 8% by weight, the brazing material layer becomes brittle, which may lead to a decrease in bonding strength.

The active metal component Ti (Zr or Hf
If the content exceeds 10% by weight, the amount of interface reaction products with the ceramic joined body increases and the bonding strength decreases, so that the content of the active metal is 10% by weight or less, preferably 5% by weight. % Should be adjusted in the range of not more than%. The content of Al is determined in consideration of the content of Si and the active metal component and the target melting point (solidus temperature) of the brazing material.
It is appropriately adjusted in the range of 0.1 to 5% by weight. In addition, other Cu-based brazing materials include Cu-Pd-Si-Ti
System, Cu-Si-Ti system, Cu-Si system or the like can be used. The thickness of the brazing material layer when a Cu-based brazing material is used,
In order to sufficiently achieve the effects of the present invention, it is preferable to adjust the thickness in the range of 30 to 80 μm.

Incidentally, each adjacent boundary (or bonding interface) between the brazing material layer 3 and the metal body 2 or the ceramic body 4 is generally unclear due to component diffusion and the like. More specifically, a diffusion layer or a reaction layer (hereinafter, collectively referred to as diffusion /
Reaction layer). In the present specification, as shown in FIG. 6, in the joining direction of the metal body and the ceramic body, the cation component having the highest content among cation components such as metal ions or silicon ions constituting the ceramic body (hereinafter, referred to as When the concentration of the main cation component is analyzed from the ceramic body side to the brazing material layer side, the position where the analysis value level of the main cation component concentration becomes 1/2 of the average concentration Cm is defined as the ceramic body. It shall be determined as the boundary BX with the brazing material layer. Similarly, when the concentration of the metal component having the highest content (hereinafter, referred to as a main metal component) among the metal components constituting the metal body is analyzed from the metal body side toward the brazing material layer side, the main metal component The position at which the analytical value level of the concentration is の of the average concentration Mm is determined as the boundary BY between the metal body and the brazing material layer. Then, the distance between the two boundaries is defined as the thickness t of the brazing material layer (however, if a distribution occurs in the thickness of the brazing material layer, the average value thereof is used).
Such analysis is performed by a known method such as electron probe micro analyzer (EPMA), EDS (energy dispersive X-ray spectroscopy), WDS (wavelength dispersive X-ray spectroscopy), Auger electron spectroscopy (AES), etc. Can be implemented.

In the above embodiment, the ceramic body 4
Has been directly brazed to the metal body 2, but in order to reduce residual stress (or thermal stress) caused by a difference in thermal expansion between the metal body 2 and the ceramic body 4 at the time of heat treatment for bonding or the like, An intermediate layer (or a buffer plate) may be interposed between the body 2 and the brazing material layer 3. This intermediate layer can be composed mainly of a soft metal such as Cu or Ni, for example, and serves to further enhance the effect of relaxing the residual stress by its own plastic deformation. Further, the intermediate layer may be made of a material having an intermediate linear expansion coefficient between the ceramic body 4 and the metal body 2, such as W alloy or Kovar. The intermediate layer can be formed by joining a thin plate made of the above material to the metal body 2 by brazing or the like, and can be similarly joined to the ceramic body 4 by brazing via the brazing material layer 3. in this case,
If the whole of the metal body 2 and the intermediate layer integrated by bonding are regarded as the metal body 2 again, it can be seen that the structure also has the structure of the bonded body described in the claims of the present invention. The metal body end face chamfered portion can be formed in this intermediate layer.

[0036]

(Example 1) Tappet (joint) 1 of the present invention
A prototype was manufactured under the following conditions in order to confirm the performance. First, as a steel material, alloy steel SN specified in JIS
By tapping and mechanically grinding the CM630, the tappet fitting 2 having the shape shown in FIG. 2 was produced. On the other hand, Si ₃ N ₄
Material 100 parts by _weight, and Al ₂ O 3 _-Y 2 _{O 3} based sintering aid by blending and molding binder was molded at a mold press at after binder removal, _{N 2} gas atmosphere 1700 ° C
Pre-sintering at 1700 ° C in N ₂ gas atmosphere
Gas pressure firing was performed at 100 atm to obtain a disk-shaped fired body.
Both sides of the fired body thus obtained were ground to form a ceramic plate 4 (thickness: 1.5 mm). Then, a brazing material foil is sandwiched between the tappet metal fitting 2 and the ceramic plate 4 and brazed in a vacuum atmosphere to form a brazing material as shown in FIG.
Various tappets 1 having the following shapes were obtained at n = 2. The brazing material foil used was an Ag-Cu-In-Ti-based brazing material (Cu: 27.25 wt%, In: 12.5 wt%).
%, Ti: 1.25 wt%, balance Ag, thickness 0.040
mm), and the brazing condition is 800 ° C. in a vacuum atmosphere.
× 2 hr, the cooling rate after brazing was 10 ° C./min.
In each of the tappets after joining, the thickness of the brazing material layer 3 is approximately 35 to 38 by EPMA measurement of a cross section.
μm.

Of the tappet samples obtained in Table 1, Nos. 1 to 3 indicate various angles on the sliding surface 4a and the joining surface 4b of the ceramic plate 4 and the outer edges of the end surface 2a of the metal body 2. In addition, the chamfers 4c, 4d, and 2c are formed with the width and width, and the notch 1a shown in FIG. 3 and the like is formed on the peripheral edge of the joint (hereinafter, referred to as a test product having a notch structure). In the display of the form of the chamfer, “C #. ##” means that the chamfer angle θ is 45 ° and the width x of the chamfer is #. ##
m. On the other hand, Nos. 4 and 5 indicate that a chamfered portion 4d is formed on the outer peripheral edge of the sliding surface 4a of the ceramic plate 4 and the chamfered portion on the joining surface side of the ceramic plate 4 and the metal body 2 is almost completely eliminated. Polishing is performed so that the outer peripheral surfaces of the ceramic plate 4, the metal body 2, and the brazing material layer 3 are substantially flush with each other (hereinafter, referred to as a test specimen for bonding outer peripheral polishing).

[0038]

[Table 1]

With respect to the above tappet, the total bonding area ratio of the brazed portion between the metal body and the ceramic plate was completely measured by an ultrasonic flaw detector, and it was confirmed that there was no abnormality. The positional relationship between the chamfered portions 4c, 4d, and 2c after the joining is analyzed by cross-sectional observation of a test sample after an endurance test described later.
The distance δ between the reference edge and the reference chamfer was measured as the minimum value in the circumferential direction. As a result, in the test sample 3, the inner edges A to C have the positional relationship shown in FIG. 3A over the entire circumference (Example), while the test samples 1 and 2
It was found that the positional relationship shown in (b) was obtained (Comparative Example). In the test samples 1 and 2, the minimum value of the distance between the inner edge A and the inner edges B and C closer to the inner edge A is indicated by a negative value as δ. In the test samples 1 to 3, the positional relationship between the inner edges B and C is C
Was located inside of B. The distance (indicated by the minimum value in the circumferential direction) of the test sample 1 was 0.15 mm, that of the test sample 2 was 0.23 mm, and that of the test sample 3 was 0.4 mm. Here, the cross section including the central axis of the test sample is polished at regular angular intervals (for example, at 5 ° intervals) around the central axis.
While observing and measuring the position of each chamfering edge sequentially while chamfering, for example, by performing X-ray CT by scanning a tomographic plane parallel to the central axis in the diameter direction of the tappet, each chamfering edge is measured. A non-destructive measurement method of the three-dimensional profile of the above may be used.

Next, these tappets were mounted on a cam motoring tester, and a durability test was performed under the following conditions.
That is, an oil temperature of 130 ° C. and a cam rotation speed of 2500
rpm, clearance between tappet and cam 1.5m
m, set load at nose top position is 350kg
The test was performed up to 1.0 × 10 ⁹ cycles. Ultrasonic flaw detection was performed every 5 × 10 ⁵ cycles on the way, and the radius R of the ceramic plate was 80 times smaller than before the endurance test.
%, When the total area ratio of defects having a size of 30 μm or more increased by 10% or more, the durability was determined to be the durability limit, and the durability life was determined by the number of cycles at that time. Table 1 shows the above results.

With respect to the test products having the notch structure (Nos. 1 to 3), the test product of No. 3 which is an example product of the present invention has better durability than the test products of Nos. 1 and 2 which are comparative examples. It turns out that it shows. On the other hand, the test products (Nos. 4 and 5) of the joint outer peripheral polishing showed even better durability, and in particular, No. 5 having a large chamfer amount showed no abnormality even when the test was performed up to the maximum cycle. .

(Embodiment 2) The ceramic body joining surface chamfer 4d and the metal body end chamfer 2c are each C0.3.
mm, the chamfered surface 4c of the ceramic body joining surface was cut out in exactly the same manner as in Example 1 except that the angle θ was either 25 ° or 30 ° and the width x was adjusted to various values. Various types of tappet test specimens were prepared. Further, in the same manner as in the first embodiment, the positional relationship between the chamfers 4c, 4d, and 3c is analyzed, and the position of the inner edge A is set as a reference position, and the inner edge B is set.
And the distance to C (indicated by the minimum value in the circumferential direction, with a positive value when it is outside A and a negative value when it is inside) and the value of δ. And these tappet test products 21 to 31 (30 and 31 where δ is negative are comparative examples)
In each case, the same durability test as in Example 1 was performed up to 1.0 × 10 ⁸ cycles to evaluate the life. Table 2 shows the above results.
Shown in

[0043]

[Table 2]

The longer the inner edge A of the ceramic body joining surface side chamfered portion 4c is located inside the chamfered portion inner edge B or C on the joining surface side (that is, the larger δ is), the longer the life is. Understand.

Example 3 The procedure was the same as in Example 3, except that the angle θ of the chamfer 4c was set to various values of 20 ° to 50 ° and the width x was adjusted to various values of 0.3 to 1.5 mm. In exactly the same manner as in Example 1, various types of tappet test products of a bonded outer peripheral polishing type were produced. And these tappet test articles 51-
The same durability test as in Example 1 was performed on 1.0 × 10
^The life was evaluated up to ⁹ cycles. Table 3 shows the above results.

[0046]

[Table 3]

The width x of the chamfered portion is 0.3 mm or 1.
When the distance approached 5 mm, a slight chipping was observed in the chamfered portion 4c, but all of them showed extremely good durability. In particular, it can be seen that the longer the value of x, the longer the life.

[Brief description of the drawings]

FIG. 1 is a front view of an overhead valve mechanism including a tappet of the present invention.

FIG. 2 is an enlarged view of the tappet of FIG.

FIG. 3 shows the tappet according to the first configuration of the present invention.
Some examples ((a) and (b)) of the form of forming a chamfered part on a ceramic body and a metal body are compared with a comparative example ((c)).
FIG.

FIG. 4 is a schematic cross-sectional view showing a modified example of a form of forming a chamfered portion on a ceramic body and a metal body in the tappet having the first configuration.

FIG. 5 shows a tappet according to a second configuration of the present invention.
FIG. 4 is a schematic cross-sectional view showing an example of a form of forming a chamfered portion on a ceramic body and a metal body.

FIG. 6 is an explanatory view showing the concept of a brazing material layer.

FIG. 7 is an explanatory diagram showing an arrangement relationship between a cam and a tappet together with a cam sliding range and an impact force distribution.

FIG. 8 is a diagram illustrating a contact angle of a cam.

FIG. 9 is a longitudinal sectional view showing the shape of the tappet test product used in the example.

[Explanation of symbols]

 Reference Signs List 1 tappet (sliding part) 2 tappet fitting (metal body) 2a end face 3 brazing material layer 4 ceramic plate (ceramic body) 4a sliding face 4b joining face 4c ceramic body sliding face chamfer 4d ceramic body chamfer chamfer Part 2c Metal body end face beveling part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G016 AA05 AA19 BB02 BB06 CA13 CA14 CA46 EA02 EA14 EA24 FA33 GA00 4E067 AA01 AA18 AB06 BM00 EA00 EB00 4G026 BA01 BB21 BC01 BC02 BD14 BG02 BH03

Claims (9)

[Claims] 1. The method according to claim 1, wherein the back surface of the ceramic body is a bonding surface.
A ceramic sliding part having a structure in which this is brazed to an end face of a metal body and having a front surface side of the ceramic body as a sliding surface, wherein a sliding surface of the ceramic body and a bonding surface of the ceramic body as well. A chamfered portion is provided on each outer peripheral edge of at least one of the end surfaces of the metal body, and an inner edge of the ceramic body sliding surface chamfered portion is an inner edge of the ceramic body joint chamfered portion and / or a metal body end surface. A ceramic sliding component, which is located inside the entire periphery of the inner edge of the chamfered portion. 2. A chamfered portion is formed on each outer peripheral edge of both the joining surface of the ceramic body and the end surface of the metal body, and the inner edge of the chamfered surface of the sliding body of the ceramic body is chamfered on the joining surface of the ceramic body. 2. The ceramic sliding component according to claim 1, wherein the ceramic sliding component is located inside the entire periphery of both the inner edge of the portion and the inner edge of the chamfer of the metal body end face. 3. An outer peripheral edge of a joining surface of the ceramic body is formed as a pin corner edge that is not chamfered, while a peripheral edge of an end face of the metal body is chamfered.
2. The ceramic sliding component according to claim 1, wherein an inner edge of the chamfered portion of the ceramic body is chamfered on an entire periphery than an inner edge of the chamfered portion of the metal body. 4. When only one of the ceramic body joining chamfer and the metal body end chamfer is formed, the inner edge of the chamfer is used as a reference chamfer, and when both are formed, Outside the inner edge of the ceramic body sliding chamfer, the inner edge of the closest one is used as a reference chamfer, and between the inner edge of the ceramic body sliding chamfer and the reference chamfer. Distance is 0.1
The ceramic sliding component according to claim 2, wherein the thickness is at least mm. 5. The ceramic sliding component according to claim 1, wherein a width of the chamfered portion on the sliding surface of the ceramic body is adjusted in a range of 0.5 to 1.5 mm. 6. A method according to claim 6, wherein the back surface of the ceramic body is a bonding surface.
In a ceramic sliding component having a structure in which this is brazed to an end surface of a metal body and the front side of the ceramic body is used as a sliding surface, a chamfered portion is formed on an outer peripheral edge of the sliding surface of the ceramic body. On the other hand, the outer peripheral surfaces of the ceramic body and the metal body are surface-finished so as to be substantially flush with a brazing joint layer formed therebetween, and a ceramic body sliding surface chamfered portion. Is 0.3 ~
A ceramic sliding part characterized by being adjusted within a range of 1.5 mm. 7. Opposing with the brazing bonding layer interposed therebetween.
7. A joint surface of the ceramic body and the metal body is finished to a substantially pin angle state by the surface finish.
The described ceramic sliding parts. 8. An angle θ formed between a reference plane orthogonal to a joining direction of the ceramic body and the metal body and a chamfer of the ceramic body sliding surface is adjusted in a range of 20 ° to 50 °. The ceramic sliding component according to any one of claims 1 to 7. 9. The ceramic sliding component according to claim 1, wherein the sliding surface is a tappet that is a cam sliding surface.