JPS63266210A - Slide device - Google Patents

Abstract

PURPOSE:To make it possible to obtain a slide motion excellent in wear- resistance by using silicon carbide ceramic as one of slide sections in a slide device, and by covering the other slide section with chromium oxide by flame spraying. CONSTITUTION:A bearing section 13 made of silicon carbide ceramic is press- fitted in a bearing housing 11, the slide surface 15a of a shaft 15 making contact with the bearing section 13 is coated with chromium oxide. When the shaft 15 is rotated, the shaft 15 and the bearing section 13 start to slide between their slide surfaces 15a, 13a. In this arrangement, since the slide surface 15a of the shaft 15 is coated with chromium oxide while the bearing section 13 is made of silicon carbide so that the friction coefficient between them is very low, thereby it is possible to obtain slide motion with no abrasion, damage or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sliding device having a sliding member made of a ceramic material.

[Prior art] Conventionally, sliding devices used under extremely severe sliding conditions such as high temperatures, high speeds, and high loads have been made of metal such as white metal, copper, or aluminum alloy and have a complete oil supply mechanism. was common. However, it is difficult to maintain complete fluid lubrication through lubrication, and solid contact inevitably occurs, resulting in scratches, wear, and seizing, or the progression of corrosion due to deterioration of the lubricating oil at high temperatures. There was a problem in that the sliding device was damaged due to such reasons.

In order to solve this problem, there have been proposed sliding devices in which the sliding movement is coated with hard ceramic particle dispersion plating, and sliding devices in which the sliding members themselves are made of ceramic material. Ceramics are superior to metals in terms of wear resistance, corrosion resistance, etc., and are also promising materials for forming the moving surfaces of sliding devices used under severe operations.

[Problems to be solved by the invention] However, the above-mentioned IP of the sliding surface! The current situation is that scratches do not disappear even when the material is ceramic, and combined with the lack of toughness, which is a drawback of ceramics, small scratches and cracks can cause damage to the entire sliding device. There was a problem.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a lubrication-free and wear-resistant structure even under extremely severe sliding conditions such as high temperatures, high speeds, and high loads. The purpose of the present invention is to provide a sliding device with excellent durability and corrosion resistance.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration. That is, the sliding device according to the present invention includes a first member made of silicon carbide (SiC) ceramics, which is movably connected to the first member, and whose sliding surface is movable relative to the first member. It is characterized by comprising a second member coated with chromium oxide (Cr203) by thermal spraying, and a fixing member that fixes the first or second member.

[Function] According to the above configuration, the first member formed of silicon carbide (S i C) ceramics and the chromium oxide (Cr203
) When the second member, which has a sliding surface coated by spraying, slides, silicon carbide ceramics and chromium oxide are both materials with high strength, high hardness, and excellent surface smoothness, The friction coefficient and specific wear amount during dynamic operation decrease.

[Example] Hereinafter, an example in which the present invention is embodied in a ceramic bearing that supports a rotating shaft will be described with reference to the drawings.

In FIG. 1, a bearing part 13 made of silicon carbide (S i C) ceramics is fitted into a bearing housing 11 by press-fitting. Possibly a shaft 15 is supported. Generally, the shaft 15 is operatively connected to a drive source (not shown).

Further, one movement surface 15a of the shaft 15 with the bearing portion 13
is coated by ceramic spraying with chromium oxide (Cr203).

Roughly speaking, each sliding surface 15 of the shaft 15 and the bearing portion 13
a and 13a are finished to a roughness of about 1 μm.

To explain the operation of the ceramic bearing configured as described above, when the shaft 15 is rotated in the direction of the arrow in FIG. 1 by a driving force from a drive source (not shown), the shaft 15 and the bearing portion 13 means its sliding surface 15a, 1
Sliding starts at 3a. At this time, one sliding surface 15a'/fi of the shaft 15 is coated by ceramic spraying with chromium oxide, the bearing portion 13 is made of silicon carbide, and the roughness of each sliding surface 15a, 13a is 1μ
Because it is finished to a milk-like finish, the coefficient of friction in the 8-motion is very small and the amount of specific wear is also very small, so even though it is without lubrication, there is no wear or damage. is obtained.

Here, an example of the test results of measuring the friction coefficient and specific wear amount of the material used between the shaft and the bearing part is shown in FIG. As a test method, the Okoshi type abrasion test was used, and as a test condition, the opening speed was set to 4.3 m/SeC. Furthermore, the second
In the figure, the ring corresponds to the shaft and the plate corresponds to the bearing part. Measured values A to F are obtained by spraying chromium oxide (Cr203) or alumina (AJh 03 ) on chromium molybdenum steel (30M415), which is the base material of the ring. These are the test results when sliding the coated material and various ceramics without lubrication, and the measured value G is the material used for conventional general bearings, such as general steel material for polished bar steel (SGD3),
These are the test results when gray cast iron (FCl2) was subjected to one movement with oil lubrication.

As is clear from FIG. 2, the sliding action A between the silicon carbide ceramic of the present invention and the ceramic coating material made of chromium oxide has a higher friction than the non-lubricated sliding action B to F of other ceramic materials. Both the coefficient and the specific wear amount are low, and when compared with the oil-lubricated 1-dynamic G of a conventional general bearing, the friction coefficient is almost the same despite no lubrication, and the specific wear amount is lower than that of the IR of the present invention. motion is better.

Further, 32M photographs (200x magnification) of the worn surface on the plate side (bearing side) after the above test are shown in FIGS. 3 to 6. Here, Fig. 3 is a 32M photograph of the worn surface of silicon carbide ceramics after the completion of the sliding test between the silicon carbide ceramics of the present invention and a ceramic spray coating material made of chromium oxide, and Fig. 4 is a 32M photograph of the wear surface of alumina ceramics against oxidation. Figure 5 is a 32M photograph of the worn surface of a chromium sprayed coating material, Figure 5 is a 32M photograph of a worn surface of a partially stabilized zirconia (PSZ) chromium oxide sprayed coating material, and Figure 6 is a 32M photograph of a worn surface of a chromium sprayed coating material made of silicon carbide ceramics. This is a 32M photograph of the worn surface.

When these are compared, the wear surface of the chromium oxide sprayed coating material of alumina ceramics shown in Figure 4, the wear surface of the partially stabilized zirconia sprayed coating material against chromium oxide shown in Figure 5, and the wear surface of silicon carbide ceramics shown in Figure 6. The worn surface of the alumina thermally sprayed coating material is highly uneven and shows traces of falling block particles, whereas the worn surface of the present invention shown in Figure 3 maintains surface smoothness and does not suffer from damage such as cracks. I can see that there is no.

As is clear from the above test results, the bearing made of the combination of silicon carbide ceramic and chromium oxide sprayed coating material according to the present invention is superior to a conventional bearing using oil lubrication or a bearing made of a combination of other ceramics. The friction coefficient and specific wear amount are both low, and the surface smoothness can be maintained, so there will be no scratches or cracks, and even under extremely harsh sliding conditions such as high temperatures, high speeds, and high loads, even without lubrication. It has excellent wear resistance and corrosion resistance, and can solve the problem of conventional bearings made of ceramic materials, where the bearings are damaged due to cracks and the like.

Here, in view of material properties such as tensile strength and coefficient of linear expansion, the silicon carbide ceramic in the present invention is preferably used on the side fixed by the fixing means. That is, taking the bearing of this embodiment as an example, it is desirable that the bearing portion 13 be formed of silicon carbide ceramics and that the shaft 15 be coated with chromium oxide by ceramic spraying.

In this embodiment, an example in which the present invention is applied to a bearing that supports a rotating shaft is shown, but it can be applied to various sliding devices such as a thrust bearing and a table slide device.

[Effects of the Invention] As detailed above, the present invention uses silicon carbide ceramics on one side of the sliding part of the sliding device and coats the other side with chromium oxide by thermal spraying, so that it can withstand high temperatures, high speeds, high loads, etc. Even under extremely severe sliding conditions, the friction coefficient is low due to the smoothness of the surface of the painting material, even without lubrication, and the specific wear rate is low due to the high strength and hardness of the painting material. Because of the low friction, it is possible to obtain excellent wear resistance and corrosion resistance, and due to the above-mentioned good surface smoothness, damage such as cracks does not occur on the sliding surface.
This has the advantage of being able to prevent damage to the bearing caused by cracks and the like.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a bearing that supports a rotating shaft, which is an embodiment of the present invention, and Fig. 2 is a comparison of the coefficient of friction of one moving member when various test pieces are used as one moving member. Figures 3 to 6 showing the relationship with the amount of wear are 32M photographs of the sliding surfaces of various test pieces. 11: Bearing housing, 13: Bearing section, 13a: Sliding surface of the bearing section with the shaft, 15: Shaft, 15a: Sliding surface of the shaft with the bearing section

Claims (1)

[Claims] 1. A first layer formed of silicon carbide (SiC) ceramics.
The member (13) is in sliding contact with the first member (13) in a movable manner, and its sliding surface (15a) is made of chromium oxide (Cr_2).
A second member (15) coated by thermal spraying of O_3)
A sliding device comprising: and a fixing member (11) that fixes the first member (13) or the second member (15). 2. The fixing member (11) is the first member (13)
The sliding device according to claim 1, wherein the sliding device is fixed.