JPH04124214A - Production of sliding member having wear resistance - Google Patents

Abstract

PURPOSE:To form a high hardness chilled layer excellent in wear resistance on the whole surface of a sliding part without causing shoulder sag to the ends of the sliding part by providing grooves to the sliding part of a sliding member, allowing these grooves to hold strip-like insulating members, respectively, irradiating the above sliding part, in the above state, with high density energy beam, and exerting remelting chilling treatment. CONSTITUTION:Grooves 5, 5 are provided to both ends of a nose part 2a of a sliding part 2 of a sliding member 1, and insulating members 6, 6 consisting of paste of hard ceramic material, such as Al2O3, ZrO2, and SiC, are held in the above grooves 5, 5. Then, the sliding part 2 is heated and remelted by the irradiation with high heat energy beam 7, such as electron beam and laser beam. At this time, the occurrence of shoulder sag of remelted metal at the ends of the sliding part 2 can be prevented by the presence of the insulating members 6, and a high hardness chilled layer 8 can be formed on the whole surface of the remelted part between the insulating members 6, 6 by means of rapid cooling by self-cooling.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method of manufacturing a sliding member having wear resistance by subjecting the surface of the sliding portion to a remelting chill treatment.

(Prior art) For example, an engine is equipped with a sliding member having a sliding part such as the cam part of a camshaft, and as the output of engines has increased in recent years, the surface pressure acting on this sliding part has also increased. Since wear resistance is required, the above sliding parts are exposed to beam thermal energy (laser beam, electron beam, TIG arc, etc.).
A method of remelting and chilling with
(Refer to the publication), or by coating or feeding alloy powder onto the sliding part and remelting and chilling it, or by remelting a high alloy using an alloy powder sheet, etc. to increase the surface hardness of the sliding part. , techniques have been proposed to obtain excellent wear resistance.

(Problem to be Solved by the Invention) Although the chilled portion obtained by the above-mentioned remelting chill treatment has a fine structure, the surface portion is remelted by rapid irradiation of beam thermal energy, so that sliding Heat is trapped at the ends of the sliding part and it melts too much, flowing down and causing sag, and after remelting, both ends of the sliding part become lower. When this sliding portion is ground, there is a problem that the contact length with the mating member is shortened due to the lack of thickness in the shoulder portion, and the surface pressure of the contact portion increases, causing abnormal wear.

In addition, when remelting is performed to reduce the amount of melting at both ends in order to prevent shoulder sagging of the sliding part, the chill hardened layer near the ends is shallow and there is a problem in terms of durability. .

Therefore, in view of the above circumstances, the present invention has been developed to provide wear resistance that prevents the occurrence of shoulder sag during remelting, secures the necessary contact length, and obtains a chill layer of sufficient depth even at the ends. An object of the present invention is to provide a method of manufacturing a sliding member having the following.

(Means for Solving the Problems) In order to achieve the above object, the method for manufacturing a sliding member of the present invention provides a method for manufacturing a sliding member such as a cam, which has a sliding member having a predetermined width, at both ends in the width direction of the sliding member. A groove is provided in the groove, and while a band-shaped heat insulating member is held in the groove, high-density energy is irradiated between the heat insulating members to perform a remelting and chilling process.

At the time of remelting, alloying elements may be added by adhering alloy powder sheets or by supplying alloy powder.

(Functions and Effects) In the method for manufacturing a sliding member as described above, a groove is provided at the end of the sliding part, and the space between the heat insulating members is remelted while the heat insulating member is held in the groove. The heat insulating effect of the groove and the heat insulating member in the groove cuts off the heat to the end of the sliding part, preventing heat from accumulating at the end, and the molten metal that has been fluidized by remelting flows down from the end. The above-mentioned heat insulating member prevents the occurrence of shoulder sagging. This creates a remelted chilled layer with sufficient depth even at the edges, ensuring the necessary contact length and depth with the mating member, creating a sliding member with excellent wear resistance. It is something that can be manufactured. Furthermore, since the heat insulating member is held in the groove, it has a strong holding force against the sliding portion, and is difficult to come off even when irradiated with energy during remelting, thereby ensuring reliable prevention of shoulder sagging.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1(A) to 1(F) sequentially show the manufacturing process of one embodiment. This example is an example of an engine camshaft.

A camshaft serving as a sliding member 1 includes a cam portion as a sliding portion 2 that comes into sliding contact with a rocker arm or the like. First, the first
As shown in Figure (A), a cast iron camshaft material is roughly machined to form a cam sliding part 2 of a predetermined width on the shaft part 3.

Next, as shown in FIG. 1(B), grooves 5.5 are provided at both ends of the nose portion 2a of the cam sliding portion 2. In the cam sliding part 2, since the nose part 2a has the most severe sliding conditions, only this part is subjected to the remelting and chilling process.

Insulating members 6, 6 are inserted into the grooves 5.5 on both sides of the sliding portion 2 as shown in FIG. 1(C). The heat insulating members 6, 6 are
A bottom part which is mounted and coated with a paste of a ceramic material such as alumina, zirconia, silicon nitride, etc., and which is inserted into the grooves 5, 5, and a blocking part which protrudes outward from above this bottom part to be higher than the surface of the sliding part 2. It is provided in a shape having.

Subsequently, while holding the heat insulating member 6.6, the surface of the sliding portion 2 is heated and remelted by beam thermal energy irradiation 7, as shown in FIG. 1CD).

At this time, the bottoms of the heat insulating members 6, 6 fit into the grooves 5.5 and have a large holding force, so they are held without coming off due to the beam heat during remelting, exhibiting a heat insulating effect and preventing shoulder sag. To prevent. Furthermore, the vicinity of the grooves 5.degree. 5 at both ends is also remelted to a depth approximately equal to that of the grooves 5, 5 due to the heat insulation provided by the heat insulating members 6, 6. The beam thermal energy is:
Known T! This is performed by irradiation with a G arc, an electron beam, a laser beam, or the like.

After the remelting and heating described above, as shown in FIG. 1(E), a chill layer 8 is obtained in which the remelted portion between the heat insulating members 6 and 6 is rapidly cooled by self-cooling and hardened.

After the above-mentioned hardening, the surface of the sliding part 2 is ground to a predetermined size, and as shown in FIG. A sliding member 1 having a moving part 2 is manufactured. By the above-mentioned grinding process, the heat insulating member 6.degree. 6 is removed, and a remelted portion of a predetermined width inside the grooves 5, 5 on both sides is formed into a wear-resistant chill layer 8 with a high surface hardness. Note that the uncured portion outside the groove 5.5 may be removed to produce the final product.

More specifically, the metal composition of the material of the sliding member 1, that is, the camshaft, is C=-3,6 in terms of weight ratio.
%, S t-2,6%, M n-0,43%, p-・
・0.019%, S-0,022%, Cu-0.8%,
Cr...0.13%, Mg-0,045%, balance Fe. The groove 5 has a depth of 211% and a width of 1.5 mm.
A slit-like groove 5 with a length of s+m s of 10 mm is formed by machining. Then, a heat insulating member 6 is provided in the grooves 5 by mounting and coating paste-like alumina.

Next, when performing the remelting process, the entire sliding member 1 is
It is preheated to .degree. C., and a TIG arc 7 is generated on the surface of the sliding part 2 using a TIG device to remelt it. The remelting conditions were a work rotation speed of 0.65 rpm.

Oscillation width 1.411, number of oscillations 30 times
The n1 current value is 90 to 110A.

When the sliding part 2 was ground after being remelted and chilled as described above, the sliding part 2 was cut, the cross section was corroded with nital, and the width of the remelted chill was measured. Although the width (cam width) was 20 g+m, a remelted chilled layer 8 with a width of 15 m1+ was obtained.

Next, FIG. 2 shows another embodiment, in which alloying elements are added using an alloy powder sheet and a remelting chill treatment is performed.

That is, as in the previous example, a sliding member 1 having a sliding part 2 is formed, grooves 5, 5 are provided at both ends of this sliding part 2, and then heat insulating members 6', 6' are provided in the grooves 5, 5. After holding the
As shown in FIG. 2, an alloy powder sheet 10 is adhered to the surface of the sliding portion 2 between the heat insulating members 6'6'. Subsequently, a dewaxing process is performed by heating, and then, as in the previous example, a portion of the alloy powder sheet 10 is remelted with a high alloy by a TIG arc 7, and after cooling, a grinding process is performed to a predetermined size.

To explain this example more specifically, the sliding member 1 is formed using the same material as in the previous example, and similar grooves 5.5 are provided at both ends of the sliding portion 2. The heat insulating members 6', 6' are held by applying paste-like silicon nitride as a mount coat. Next, an alloy powder sheet 10 is placed on the surface of the sliding part 2.
This alloy powder sheet 10 is
It is made into a high alloy by adding further alloying elements to the composition of the base material, for example, it is formed into a sheet shape with 95% eutectic alloy powder with a powder particle size of 100 mesh or less and 5% acrylic resin with the following composition. . The composition example of the above metal powder is, in terms of weight ratio, C...3.6%, MO...9.8%, P...2
．． 1%, Cr-4.5%, Ni-L, 1%, balance Fe
It is.

The sliding member 1 to which the alloy powder sheet 10 is adhered is so
After performing a dewaxing process in which the acrylic resin in the alloy powder sheet 10 is removed by heating in N2 gas at o'c for one hour, the entire sliding member 1 is preheated to 300°C, and the T for the alloy powder sheet 10 between the heat insulating members 6', 6'
A TIG arc 7 is generated using an IG device to remelt the surface of the sliding portion 2 from the alloy powder sheet 10. The remelting conditions were a work rotation speed of 0. fi5rp■, oscillation width 14
■1, oscillation frequency 30 times/sin, current value 80~1
It is 00A.

The cooling and grinding processes after the above remelting were performed in the same manner as in the previous example, and as a result, a high alloy remelted chill layer was obtained on the surface of the sliding portion 2 with the same width and depth as in the previous example.

In particular, since the eutectic alloy powder in the alloy powder sheet 10 as described above has a low melting point, it has high fluidity during remelting.
The effect of preventing shoulder sagging by the grooves 5, 5 and the heat insulating member 6'6' is significant.

The present invention is applicable to various sliding members such as rocker arms and swing arm sliding parts in addition to the cam portion of the camshaft foot. Further, the material and shape of the heat insulating member are not limited to the structure of the embodiment, and a pre-formed one may be attached.

Furthermore, instead of adhering the alloy powder sheet, the alloy powder may be injected at the time of remelting, and in this case, the heat insulating member has the function of preventing the alloy powder from scattering in addition to preventing shoulders from sagging.

[Brief explanation of the drawing]

Figures 1 (A) to (F) are cross-sectional views of main parts sequentially showing the manufacturing process of a sliding member in one embodiment of the present invention, and Figure 2 is a main part of the sliding member in the middle of the manufacturing process showing another example. FIG. 1... Sliding member, 2... Sliding part, 5...
...Groove, 6゜6'...Insulation member, 7...
...Beam (TIG arc) 8...Chill layer, 10...Alloy powder sheet. Diagram

Claims (1)

[Claims] (1) In a sliding member having a sliding part of a predetermined width, such as a cam, grooves are provided at both ends in the width direction of the sliding part, and a band-shaped heat insulating member is held in the groove, and between the heat insulating members 1. A method for manufacturing a sliding member having wear resistance, the method comprising performing a remelting chill treatment.