JP2001220255A - Sliding ceramic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sliding ceramic part having excellent durability of the bonded part between a ceramic member and a metallic member. SOLUTION: The outer circumferential edge of a sliding face 4a of the ceramic member 4 is provided with a chamfered part 40 extending from a ceramic plate 4 through a soldering material layer 3 to the metallic member 2. The ceramic plate 4, the soldering material layer 3 and the metallic member 2 form a nearly flat continuous plane on the chamfered part 40. The angle θbetween a standard plane L1 perpendicular to the bonding direction of the ceramic plate 4 with the metallic member 2 and the continuous plane (standard plane) L2 of the chamfered part 40 is adjusted to 30-60 deg..

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 rocker arm, a valve bridge and a valve lifter of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in the above-mentioned sliding parts, a sliding portion to which the highest surface pressure is applied, that is, a portion requiring the most sliding characteristics, is constituted by a ceramic plate and brazed. Those having a structure joined to a metal body by a method such as the one described above are often used. For example, chipping or chipping is likely to occur at the time of manufacturing or handling after manufacturing,
In order to prevent this, it is indispensable to apply a certain amount of chamfer 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-mentioned chamfering involves 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 the butt brazing structure, a kind of groove-shaped notch is formed in the outer peripheral portion of the brazing material layer. Therefore, for example, when stress concentrates 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 tend to occur due to plastic deformation of the outer peripheral portion of the soft brazing material layer. .

[0004] It is an object of the present invention to solve the above-mentioned problems and to provide a ceramic sliding part having excellent durability at a joint between a ceramic body and a metal body.

[0005]

Means for Solving the Problems and Action / Effect To solve the above-mentioned problems, a ceramic sliding component of the present invention uses a ceramic material as a metal through a brazing material layer with the back surface of the ceramic material as a joining surface. It has a structure joined to the end face of the body, the surface side of the ceramic body as a sliding surface,
A chamfered portion extending from the ceramic body to the metal body via the brazing material layer is formed on the outer peripheral edge of the sliding surface of the ceramic body.

That is, the present inventors have made intensive studies in view of the above situation, and as a result, have found that the notch structure on the outer periphery of the brazing material layer has been removed and the chamfered portion on the sliding surface side has been formed. Have been found to be a necessary condition for improving the durability of the sliding component, and the present invention has been completed. In addition, the chamfered portion refers to a slope-shaped portion formed in a down form from the outer edge of the sliding surface of the ceramic body to a position extending to the outer periphery of the metal body. It may be formed as a convex R surface or a convex downward (for example, a concave R surface).

If a chamfer is formed on at least one of the outer peripheral edge of the joining surface of the ceramic body and the end surface of the metallic body, the above-described circumferential notch structure is formed in the outer peripheral portion of the joining layer (brazing material layer). . However, as in the ceramic sliding component of the present invention, for example, in a ceramic joined body having a cutout structure after joining, on the outer peripheral edge of the ceramic body sliding surface,
Through a brazing material layer from the ceramic body, chamfering over the metal body is performed, for example, by grinding or the like, and in the case of the configuration in which the notch structure is removed, when the cam or the like slides by contacting the sliding surface of the ceramic body. In addition, it is possible to dramatically reduce stress concentration on the outer peripheral portion of the brazing material layer, and thus plastic deformation thereof, thereby realizing a ceramic sliding component with improved durability. In addition, since a predetermined inclination angle (chamfer angle) is provided at the time of grinding and the notch structure is removed, the chamfered portion on the ceramic sliding surface side can be simultaneously performed in one step, and the processing step is simplified. Further, by appropriately adjusting the inclination angle (chamfer angle), unnecessary grinding of the metal member can be avoided, and thus the material cost can be reduced. The grinding in this case means polishing or cutting.

Specifically, the chamfered portion is a ceramic body,
The brazing material layer and the metal body may be C-chamfered portions that are substantially flush with each other, or may be an R-chamfered portion formed in a convex shape by the ceramic body, the brazing material layer and the metal body. In any of the chamfered shapes, the occurrence of chipping or chipping during sliding can be prevented or suppressed at the outer peripheral edge of the sliding surface of the ceramic body.

In the present invention, the angle θ between the reference plane perpendicular to the joining direction of the ceramic body and the metal body and the chamfered portion can be in the range of 30 ° to 60 °. When the angle θ is less than 30 °, the grinding margin of the ceramic body increases, so that the efficiency may be deteriorated. When the angle θ exceeds 60 °, the sliding surface of the ceramic body may be chipped and chipping or the like may easily occur. There is. The angle θ is preferably 40
It is preferable to adjust the angle to between 50 and 50 degrees. When the chamfered portion is the above-described R chamfered portion, the angle θ is a reference surface L1 orthogonal to the joining direction of the ceramic body and the metal body, and a reference surface connecting the inner edge / outer edge of the R chamfered portion. Defined as the angle between L2.

[0010] The thickness of the ceramic body may be 0.7 to 0.7 in the joining direction of the ceramic body and the metal body.
It can be 1.5 mm. If the thickness is less than 0.7 mm, useless thinning of the ceramic body may be caused, and the strength of the ceramic body itself may be insufficient, which may cause defects such as chipping and decrease in wear resistance or fatigue resistance. . On the other hand, if the thickness exceeds 1.5 mm, the grinding allowance of the ceramic body increases, leading to a decrease in grinding efficiency, and in addition, the material cost increases and the cost may increase. The thickness of the ceramic body is preferably adjusted to 0.8 to 1.2 mm.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically 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. 2 is an enlarged view of the tappet 1. 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 disk shape as a sintered body of silicon nitride, and the sliding base portion 1b
Are overlapped and joined to the flat end face of In addition, brazing material layer 3
Is used as a brazing material. The end face of the ceramic plate 4 on the opposite side to the side in contact with the brazing material layer 3 has a sliding surface 4 with the cam 100.
a.

As shown in FIG. 2, the sliding surface 4a of the ceramic plate 4 is crowned (small curvature protruding at the center). In this crowning, when the metal body 2 and the ceramic plate 4 are brazed and cooled, the metal body 2 shrinks more than the ceramic plate 4 due to the difference in the coefficient of thermal expansion between the metal body 2 and the ceramic plate 4. The ceramic plate 4 is formed by elastically deforming the ceramic plate 4 so that the central portion is raised.

A chamfered portion 40 extending from the ceramic plate 4 to the metal body 2 via the brazing material layer 3 is formed on the outer peripheral edge of the sliding surface 4a of the ceramic plate 4. In the chamfered portion 40, the ceramic plate 4, the brazing material layer 3, and the metal body 2 form a continuous surface that is connected to each other substantially flush. As shown in FIG. 3, a reference plane L1 orthogonal to the joining direction of the ceramic plate 4 and the metal body 2 is connected to a continuous plane (reference plane) L2 of the chamfered portion 40 (the inner edge 40a and the outer edge 40b of the chamfered portion 40). More preferably, the angle θ between the reference plane L1 and the continuous plane L2 is in a range of 30 ° to 60 ° (in this embodiment, 4 ° in C-chamfering).
5 °). The thickness d1 of the ceramic plate 4 in the joining direction of the ceramic plate 4 and the metal body 2
Is 0.7 to 1.5 mm (1.0 mm in this embodiment).

Next, a method of manufacturing the tappet 1 of this embodiment will be described. As shown in FIG. 4A, the sliding surface 4a
And chamfered portions 4c, 4 on the outer peripheral edge of the joining surface 4b.
The ceramic plate 4 provided with d and the metal body 2 provided with the chamfered portion 2c on the peripheral edge of the end face 2a are brazed and joined by a known method to obtain a joined body 200. In this case, the outer peripheral exposed surface of the brazing material layer 3 is a bottom surface and the chamfered portions 4d,
Notch 1a in the circumferential direction having a substantially C-shaped cross section with 2c as the inner surface
Is generated.

In the joined body having the notch 1a, the outer periphery is polished so that the notch 1a almost completely disappears and the outer periphery of the sliding surface 4a of the ceramic plate 4 does not become square. Chamfering is performed so that the outer peripheral surfaces of the metal body 2 and the brazing material layer 3 are substantially flush. As a result, FIG.
As shown in (b), the ceramic plate 4, the brazing material layer 3, and the metal body 2 form a continuous surface that is connected to each other substantially flush, and as shown in FIG. The reference plane L2 and the reference plane L1 orthogonal to the joining direction of the ceramic plate 4 and the metal body 2 cross obliquely. In FIG. 4B, a portion shown by a broken line is a grinding allowance.

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 is used for idling.
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 (that is, a position near the center of mass of the tappet 1). However, in the high-speed rotation state, under the influence of the inertia of the valve train and the form of the cam taper,
As shown by the solid line in the figure, a very large impact force is applied to the vicinity of the outer peripheral edge of the sliding surface 4a. Even when the curvature of the crowning formed on the sliding surface 4a is small and the amount of cam taper is large, a large impact force may be applied to the outer peripheral edge of the tappet 1.

In the tappet 200 having the notch 1a as shown in FIG. 4A, cracks and peeling may occur at the notch due to the impact. However, the tappet 1 according to the present invention shown in FIG.
At the outer peripheral edge of the sliding surface 4a of the ceramic plate 4, the outer peripheral surfaces of the ceramic plate 4 and the metal body 2 are substantially flush with the brazing material layer (brazing joining layer) 3 formed therebetween. And beveled by polishing or the like. According to this configuration, the notch 1a at the joining peripheral portion as shown in FIG. 4A is substantially eliminated, so that the occurrence of cracks and peeling due to the notch is extremely effectively prevented.

Next, as shown in FIG.
The chamfered portion formed on the outer peripheral edge of the sliding surface 4a may be an R chamfered portion 42 formed in a convex shape by the ceramic body 4, the brazing material layer 3, and the metal body 2. In this case, the angle θ between the reference plane L2 connecting the inner edge 44 and the outer edge 43 of the R chamfered portion 42 and the reference plane L1 perpendicular to the joining direction of the ceramic body 4 and the metal body 2 is 30 to 60. ° (in this embodiment, 45 °).

In the above tappet 1, as the Fe-based material constituting the metal body 2, various carbon steels, alloy steels (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) 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.

The brazing material for forming the brazing material layer 3 may be an Ag-based brazing material containing Ag as a main component. 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 the interface reaction product 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%. In addition,
The content of Al is 0.1 to 0.1 in consideration of the content of Si and the active metal component and the target melting point (solidus temperature) of the brazing material.
Adjust appropriately within the range of 5% by weight. In addition, Cu other than the above
Cu-Pd-Si-Ti, Cu-
Si-Ti type, Cu-Si type and the like can be used. The thickness of the brazing material layer when a Cu-based brazing material is used is preferably adjusted in the range of 30 to 80 μm in order to sufficiently achieve the effects of the present invention.

Incidentally, each adjacent boundary (or bonding interface) between the brazing material layer 3 and the metal body 2 or the ceramic body 4 is often unclear due to component diffusion or 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 microanalyzer (EPMA), EDS (energy dispersive X-ray spectroscopy) and WDS (wavelength dispersive X-ray spectroscopy), and Auger electron spectroscopy (AES). 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.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Tappet (ceramic sliding part) 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
For 100 parts by weight of the raw material, 10 parts by weight of an Al ₂ O ₃ —Y ₂ O ₃ -based sintering aid and 5 parts by weight of a forming binder were blended, molded by a die press, and debindered. atmospherically pre-sintered at 1700 ° C. at ₂ atmosphere, further 1700 ° C. in a _{N 2} gas atmosphere, forms a gas pressure at 100 atm, to obtain a disk-shaped sintered body. Both surfaces of the fired body thus obtained were ground to form a disk-shaped ceramic plate 4.
4 mm, thickness 1.0 mm).

Then, a brazing material foil is interposed between the tappet fitting 2 and the ceramic plate 4 and brazed in a vacuum atmosphere to form a joined body 20 having a shape shown in FIG.
0 was obtained at n = 5 (Nos. 1 to 5). 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)
The brazing conditions were 800 ° C. × 2 hr in a vacuum atmosphere, and the cooling rate after brazing was 10 ° C./min. In addition, in each of the tappets after the joining, the thickness of the brazing material layer 3 was found to be approximately 35 to 38 μm by EPMA measurement of the cross section.

The obtained joined body 200 is a ceramic plate 4
The chamfered portions 4c, 4d, 4c, 4d, at various angles and widths are provided on the outer peripheral portion of the sliding surface 4a and the joining surface 4b of the
2c are formed, and the notch 1 shown in FIG.
a is formed. In this joined body 200, the ceramic body 4 is kept until the notch 1a is almost completely eliminated.
C-chamfering (angle θ = 45 ° (see FIG. 3)) extending from the sliding surface 4a to the brazing material layer 3 and the metal body 2 by grinding, the tappet 1 according to the present invention as shown in FIG. Examples 1 to 5) were obtained.

Further, as a test product of a comparative example, a joined body 200 (FIGS. 8 and 4 (a)) in which the thickness of the ceramic body 4 is 1.5 mm was prepared at n = 10 (Nos. 6 to 15). did. Among the joined bodies 200, No. With respect to Nos. 6 to 10, as shown in FIG. 9, until the notch 1a disappears almost completely, the outer peripheral surface 46 of the brazing material layer 3 and the outer peripheral surface 26 of the metal body 2 Polishing is performed in a direction parallel to the joining direction of the plate 4 and the metal body 2,
Thereafter, the outer peripheral edge of the sliding surface 4a of the ceramic body 4 was subjected to C chamfering (at an angle of 45 °) to obtain Comparative Examples 6 to 10. In this case, the chamfered portion 48 is
And does not straddle the brazing material layer 3 and the metal body 2. Further, among the joined bodies 200, 11
With respect to Nos. 15 to 15, the tappets without the chamfering (grinding) processing but with the notch 1a remaining were used.
~ 15.

Each test article (tappet) of the above Examples and Comparative Examples was mounted on a cam motoring test machine, and a durability test was performed under the following conditions. That is, the oil temperature is 130 ° C.,
The cam rotation speed is 2500 rpm, the clearance between the tappet and the cam is 1.5 mm, the set load at the nose top position of the cam is 350 kgf, and the maximum is 2.0 × 10 ⁷
Tested to cycle. Table 1 shows the results.

[0033]

[Table 1] With respect to the test articles having Notches 1a (Comparative Examples 11 to 15), cracks were observed until 2.0 × 10 ⁷ cycles were reached.
Cracks and the like occurred. On the other hand, Examples 1 to 5 and Comparative Example 6
With respect to No. 10 to 10, no crack, crack or the like occurred in the brazing material layer or the like until 2.0 × 10 ⁷ cycles.

However, with respect to the test articles of Comparative Examples 6 to 10, after the joining step of the ceramic body and the metal body, a polishing step for removing the notch 1a and chamfering of the outer peripheral edge of the sliding surface 4a are performed. Two steps of the chamfering step are indispensable. On the other hand, for the test products of Examples 1 to 5, the removal of the notch and the chamfering of the outer peripheral edge of the sliding surface are simultaneously performed in one step of the chamfering step. Good. Furthermore, compared to the test articles of Comparative Examples 6 to 10, the test articles of Examples 1 to 5 have a reduced grinding allowance, which leads to a reduction in material costs.

For the test pieces 1 to 5 of the embodiment, the angle θ of chamfering (see FIG. 3) was set to 20 °, 30 °,
When the same cam motoring test was performed at 60 ° and 70 °, no abnormality occurred up to 2.0 × 10 ⁷ cycles for each test product. The inner edge 40a of the chamfer 40 was slightly unevenly worn. In addition, the test product at θ = 20 °
Grinding allowance for chamfering is θ = 30 °, 60 °, 70 °
More than the test specimens.

Further, with respect to the test articles 1 to 5 of the examples,
The thickness d1 of the ceramic body (see FIG. 3) is 0.5 mm,
When the same cam motoring test was performed with 0.7 mm, 1.5 mm, and 1.7 mm, d1 = 0.7 m
No abnormality occurred in the test specimens of m and 1.5 mm up to 2.0 × 10 ⁷ cycles. On the other hand, for the test specimen with d1 = 0.5 mm, cracks occurred in the ceramic body at 2.2 × 10 ⁵ cycles. In the test specimen with d1 = 1.7 mm, although no abnormality occurs, d1 = 0.7 mm, 1.
The grinding allowance was larger than that of a 5 mm test product.

In the above embodiment, the C chamfering process was performed to remove the notch 1a. However, the tappet from which the notch 1a was removed by the R chamfering process as shown in FIG. Showed excellent durability.

[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 is a schematic cross-sectional view showing an enlarged main part of the tappet of FIG. 2;

FIG. 4 is a schematic cross-sectional view for explaining a method of manufacturing the tappet of FIG.

FIG. 5 is an enlarged schematic cross-sectional view showing a main part of a modification of the tappet of FIG. 1;

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 longitudinal sectional view showing a shape of a joined body before grinding used in the example.

9 is an enlarged longitudinal sectional view showing a shape obtained by chamfering an outer peripheral edge of a ceramic body of the joined body of FIG. 8;

[Explanation of symbols]

 Reference Signs List 1 tappet (ceramic 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 40 chamfer (C chamfer) 42 R chamfer

Continued on the front page F term (reference) 3G016 AA05 BB02 BB06 BB08 CA13 CA46 EA03 EA14 EA24 FA33 GA00 4G026 BA01 BA17 BB21 BB24 BC01 BC02 BD12 BD14 BF16 BF24 BG02 BH01 BH03

Claims (6)

[Claims] 1. The method according to claim 1, wherein the back surface of the ceramic body is a bonding surface.
In a ceramic sliding component having a structure in which the ceramic body is joined to an end face of a metal body via a brazing material layer, and a surface side of the ceramic body as a sliding surface, an outer peripheral edge of the sliding surface of the ceramic body Wherein a chamfered portion from the ceramic body to the metal body via the brazing material layer is formed. 2. The chamfered portion according to claim 1, wherein the ceramic body, the brazing material layer, and the metal body are substantially flush with each other.
The ceramic sliding component according to claim 1, wherein the ceramic sliding component is a chamfer. 3. The chamfered portion is formed in a convex shape by the ceramic body, the brazing material layer and the metal body.
The ceramic sliding component according to claim 1, wherein the ceramic sliding component is a chamfer. 4. An angle θ between a reference plane orthogonal to a joining direction of the ceramic body and the metal body and the chamfered part.
The ceramic sliding component according to any one of claims 1 to 3, wherein is adjusted within a range of 30 ° to 60 °. 5. The ceramic body according to claim 1, wherein a thickness of the ceramic body is in a range of 0.7 to 1 in a joining direction of the ceramic body and the metal body.
The ceramic sliding part according to any one of claims 1 to 4, which is set to 5 mm. 6. The ceramic sliding component according to claim 1, wherein the sliding surface is a tappet that is a cam sliding surface.