JPH0519339U - Sliding material - Google Patents

Abstract

(57) [Summary] [Purpose] Stabilizing the sealing function for seals and bearing sliding materials used in rotating and reciprocating machines.
It is a sliding material that has a long life, a long tightening interval, and labor saving. [Structure] The surface of a member made of a plastic material containing Teflon as a main component and a member that slides while maintaining a surface pressure are coated with a material having a high thermal conductivity and a small linear expansion coefficient, and then coated. Sliding material with pits processed on the surface.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a sliding material for seals and bearings used in rotating and reciprocating machines.

[0002]

[Prior Art]

 FIG. 4 is a longitudinal sectional view of a shaft seal device for a reciprocating pump that has been conventionally used. In FIG. 4, 1 is a reciprocating shaft, 2 is a gland packing, 3 is a holding metal fitting, 4 is a panel, 5 is a bolt, and 6 is a casing. The leakage of the fluid inside the machine X to the outside Y is sealed by the sliding surface S of the reciprocating shaft 1 and the gland packing 2.

In order to improve the sealing property, the gland packing 2 is pressed down by the bolts 5 via the metal fittings 3 to generate a high surface pressure on the sliding surface S. For this reason, the sliding surface S is likely to be non-lubricated, and the material for the gland packing 2 is a plastic material having Teflon as a main component with good solid lubricity, and the reciprocating shaft 1 is made of a high hardness ceramic coating material. It is used to prevent seizure.

[0004]

[Problems to be solved by the device]

A characteristic of Teflon-based plastics is that friction between plastics is smaller than between metal surfaces, and when Teflon moves to the mating surface, friction characteristics improve. On the other hand, the coating material of the reciprocating shaft 1 has a high hardness and a small surface roughness, and has the following two design points. One is to have high thermal conductivity and a small coefficient of linear expansion to reduce deformation due to local frictional heat. The other is to make it easier to transfer Teflon material. The typical material of the former is a WC (tungsten carbide) material and the latter is a Cr ₂ O ₃ (chromium oxide) material.

[0005] The WC material is a material that is particularly excellent in seizure resistance because it has good thermal conductivity, but because the surface is dense and has a mirror-like finish, the transferability of Teflon is worse than that of Cr ₂ O ₃ and It tends to abrade CFCs. Even if the surface roughness is large, the wear is large. On the other hand, Cr ₂ O ₃ has pits peculiar to the sprayed surface on the surface within a range where the surface roughness does not deteriorate, and Teflon is transferred to this portion, so that wear is reduced.

Regarding the transfer of Teflon, the surface αPT color check before sliding showed a red indication in the pits, whereas after the sliding there was no indication, and the residue between the pits was Teflon. It has been confirmed and is obvious.

However, since Cr ₂ O ₃ has a low thermal conductivity and the adhesive force with the base material is much smaller than WC, in the unlikely event that the gland packing is overtightened and a large friction heat is generated, The thermal stress generated in the coating may damage the coating material. If the wear increases, the packing cannot be tightened any more, and a leak occurs, which causes the operation of the mother machine to stop.In the case of damage to the coating material, a large leak suddenly occurs and the same situation occurs. Become.

[0008]

[Means for Solving the Problems]

 The present invention solves the above-mentioned conventional problems, and the surface of a member made of a plastic material containing Teflon as a main component and a member that slides while maintaining a surface pressure have high thermal conductivity, It is a sliding material that is coated with a material with a small expansion coefficient and then processed into pits on the surface of the coating material.

That is, it is an object of the present invention to provide a sliding member that keeps sliding stability of a member made of a plastic material and reduces wear.

[0010]

【Example】

 One embodiment of the present invention is shown in FIG. FIG. 1 is a vertical cross section of the reciprocating pump shaft sealing device as in FIG. The fluid in the machine X inside the casing 6 applies surface pressure to the sliding surface S of the gland packing 2 and the reciprocating shaft 1 by means of the bolt 5, the restraining metal 3 and the spring 4 to prevent the fluid from leaking to the outside Y. There is.

As a material, the gland packing 2 is a member made of a plastic material containing Teflon as a main component, and the surface of the reciprocating shaft 1 that slides on the gland packing 2 while maintaining a surface pressure has a high thermal conductivity. A WC material having a small linear expansion coefficient was coated. As shown in FIG. 2, pits 7 were formed on the surface of the WC coating material (unit: mm 2). The shape is a simulation of the actually measured surface condition of Cr ₂ O ₃ shown in FIG.

That is, pits are formed on a precision-finished sliding surface within a range where the surface roughness does not change, and the pits are processed to have the same shape as the pits generated after finishing the Cr ₂ O ₃ coated surface. The pits have a maximum depth of 5 μm and a maximum hole diameter of 20 μm generated on the precision finished Cr ₂ O ₃ coated surface, and the entire surface is machined at a pitch of 0.1 to 0.3 mm. The sliding surface is generally processed by sailboat peening or blasting.

Explaining the operation of this embodiment, if the coating material is a WC-based material, the material has a large thermal conductivity and a small linear expansion coefficient. Since the transferability of Teflon is also improved, it has low friction and excellent seizure resistance, and acts to achieve the sliding function with a small amount of wear.

[0014]

[Effect of the device]

Since the present invention is configured as described above, the Teflon material of the gland packing is easily transferred to the reciprocating shaft that is a sliding member, and the reciprocating shaft has excellent mechanical characteristics as a sliding member. Even if the packing is excessively tightened, the coating layer will not be damaged. That is, it is possible to realize a sliding material that incorporates only the advantages of the sliding materials of the WC coating and the Cr ₂ O ₃ coating material. As a result, a sliding material can be obtained in which the packing has low wear, the sealing function is stable, the life is long, the tightening interval is long, and labor is saved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a reciprocating pump shaft sealing device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a partial cross-sectional view of a processed surface of a Cr ₂ O ₃ coating material.

FIG. 4 is a vertical cross-sectional view of a conventional shaft seal device for a reciprocating pump.

[Explanation of symbols]

 1 Reciprocating shaft (sliding material) 2 Gland packing 3 Suppression metal fitting 4 Spring 5 Bolt 6 Casing 7 Pit S Sliding surface X Inside machine Y Outside machine

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10N 30:06 40:02 50:08

Claims (1)

[Scope of utility model registration request] 1. A material having a high thermal conductivity and a small linear expansion coefficient is coated on the surfaces of a member made of a plastic material containing Teflon as a main component and a member sliding on each other while maintaining a surface pressure. After that, a pit is formed on the surface of the coating material, which is a sliding material.