JP2005257035A - Multilayer bearing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sliding part in which the slidability of a sliding portion is increased and the wear resistance and fatigue resistance of the other portions are increased by a gas nitrocarburizing treatment and a method of manufacturing the sliding part. <P>SOLUTION: The method of manufacturing the sliding part comprises a step for forming a lead bronze alloy layer 3 functioning as the sliding portion 30a on the first surface 9 of a steel member 1, a step for forming a coated layer 4 on the lead bronze alloy layer, a step for gas nitrocarburizing treatment of the second surface 11 of the steel member not covered by the lead bronze alloy layer 3, and a step for removing the coated layer 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sliding bearing component and a method for manufacturing the same.

Conventionally, as a sliding bearing sliding component, there is one in which a sliding portion made of a multilayer bearing material including a lead bronze alloy layer is formed on the surface of a steel back metal (steel member) (see Patent Document 1). A sliding portion made of a lead bronze alloy has good sliding properties such as being hard to cause seizure compared to a sliding portion made of a bronze alloy not containing lead.
JP 2003-90343 A

  However, when using a lead bronze alloy layer for the sliding part, gas soft nitriding treatment is applied to the exposed surface of the steel back metal where the lead bronze alloy layer is not formed in order to improve wear resistance and fatigue resistance. May be applied. In this case, the formation of the compound layer (made of iron carbide or iron nitride) by gas soft nitriding is hindered by the evaporation of lead and cannot be performed well. This is mainly because lead evaporates or scatters during gas soft nitriding performed at a high temperature and adheres to the steel surface, preventing the penetration of carbon (C) and nitrogen (N) into the steel. is there.

  The present invention has been made in view of the above problems, and aims to favorably perform a gas soft nitriding treatment on a steel sliding component having a lead bronze alloy as a bearing alloy layer, It is an object of the present invention to provide a sliding part in which the sliding property of the sliding part is improved and the wear resistance and fatigue resistance of other parts are improved by gas soft nitriding, and a manufacturing method thereof.

  According to a first aspect of the present invention, there is provided a method for manufacturing a sliding component comprising: forming and covering a lead bronze alloy layer functioning as a sliding portion so as to cover a first surface of a steel member; A step of forming a covering layer, a step of gas soft nitriding the second surface of the steel member not covered with the lead bronze alloy layer, and a step of removing the covering layer. To do.

  The manufacturing method of the sliding component of the second invention includes a step of forming a copper underlayer on the first surface of the steel member, and a step of forming a lead bronze alloy layer functioning as a sliding portion on the copper underlayer. A step of forming a coating layer on the lead bronze alloy layer, a step of gas soft nitriding the second surface of the steel member not covered with the lead bronze alloy layer, and a step of removing the coating layer It is characterized by providing.

  According to a third aspect of the present invention, there is provided the method for manufacturing a sliding component according to the first or second aspect, wherein the coating layer is a copper plating layer formed by copper plating.

  According to a fourth aspect of the present invention, there is provided the method for manufacturing a sliding component according to the first or second aspect, wherein the coating layer is a lead-free bronze layer containing no lead.

  According to a fifth aspect of the present invention, there is provided a method for manufacturing a sliding component, wherein the coating layer is a carbon-proof material layer formed by applying a carbon-proof material in the first or second invention.

  According to a sixth aspect of the present invention, there is provided a method for manufacturing a sliding component comprising: forming a lead bronze alloy layer functioning as the sliding portion on the first surface of a steel back metal; and welding a steel ball portion to the steel back metal. A step of forming a coating layer on the lead bronze alloy layer, a step of gas soft nitriding the surface of the steel back metal and the surface of the ball portion not covered with the lead bronze alloy layer, and the coating A step of removing the layer; and a step of forming a through-hole penetrating the back metal and the ball portion and opening in the sliding portion.

  The sliding component of the seventh invention includes a substantially flat steel back metal, a substantially spherical ball part, and a lead bronze alloy sliding part formed so as to cover the first surface of the steel back metal. A through-hole penetrating the back metal and the ball part and opening in the sliding part, and the second surface of the back metal and the surface of the ball part not covered with the sliding part made of lead bronze alloy Is characterized by gas soft nitriding.

  A piston pump motor according to an eighth aspect is characterized by including the sliding component according to the seventh aspect.

  According to the first aspect of the present invention, a sliding portion made of a lead bronze alloy layer is formed on the steel member, and the exposed surface of the steel member not covered with the lead bronze alloy layer is subjected to wear resistance and resistance. Gas soft nitriding can be favorably performed to improve fatigue. This is because the lead bronze alloy layer is covered with a coating layer during gas soft nitriding, which is normally performed at a high temperature, and the lead existing in the lead bronze alloy layer evaporates and scatters. It is because it can prevent adhering to the surface which is not covered with the layer.

  According to the second invention, similarly to the first invention, a sliding part made of a lead bronze alloy layer is laminated on the steel member, and the surface of the steel member not covered with the lead bronze alloy layer Can be gas nitrocarburized satisfactorily. However, since a copper base layer is provided between the lead bronze alloy layer and the steel member surface, the adhesion of the lead bronze alloy layer is improved even when the lead bronze alloy layer is formed by sintering.

  According to the third invention, since the coating layer is a copper plating layer formed by copper plating, there is no fine gap compared to the case where the coating layer is formed by sintering or the like, and from the lead bronze alloy layer It is possible to reliably suppress the evaporation of lead. For this reason, the thickness of the coating layer can be reduced.

  According to 4th invention, since a coating layer is a lead free bronze layer which does not contain lead, a coating layer with good adhesiveness with a lead bronze alloy layer is formed. Further, even if the lead-free bronze layer cannot be completely removed, the lead-free bronze layer has good slidability to some extent, so that the slidability of the sliding component is not greatly reduced. Moreover, the same equipment as the lead bronze alloy layer formation can be used for the formation of the lead-free bronze layer, and therefore the manufacturing process can be simplified and the cost can be reduced.

  According to 5th invention, since a coating layer is a carbon-proof material layer formed by apply | coating a carbon-proof material, a coating layer can be formed simply.

  According to the sixth invention, it is possible to produce a sliding part having a steel ball part that is swingably connected to another member (such as a piston) and a steel back metal that supports the sliding part as a steel member. it can. Further, as with the first invention, a sliding portion made of a lead bronze alloy layer is laminated on the steel member and is not covered with the lead bronze alloy layer. The surface of the steel member can be favorably gas soft nitrided. Further, since the through hole that penetrates the back metal and the ball portion and opens in the sliding portion is formed, the contact surface pressure of the sliding portion can be adjusted by supplying hydraulic pressure or the like to the sliding portion.

  According to the seventh invention, since the sliding part has a sliding part made of a lead bronze alloy layer on the steel back metal, the sliding part can slide on the plate well, and other members Since it has a steel ball portion that is pivotably connected to a (piston or the like), the sliding part can be used as a shoe for a piston pump motor. In addition, since the sliding part forms a back metal that penetrates the back metal and the ball part and a through hole that penetrates the ball part and opens in the sliding part, the supply of the sliding part by hydraulic pressure etc. to the sliding part The contact surface pressure can be adjusted. Moreover, since the exposed surface of the steel member on which the lead bronze alloy layer is not formed is gas soft nitrided, it is possible to improve the wear resistance and fatigue resistance of the surface other than the sliding portion.

  According to the eighth invention, the sliding component of the seventh invention is applied to the piston pump motor, so that the sliding part of the sliding part is seized or a failure due to wear or fatigue other than the sliding part of the sliding part. The piston pump motor which prevented can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  A first embodiment of a method for manufacturing a sliding component will be described with reference to the process diagram of FIG.

  The first step is a step of preparing a steel back metal 1 (steel member) and cleaning the surface by degreasing and the like. Here, the sliding component main body 101 having a clean surface is obtained. In the second step, the copper underlayer 2 is formed and applied to the sliding portion surface 9 (first surface) which is a part of the surface of the back metal 1 by a general method such as plating. For example, copper sulfate plating can be used. The thickness of the copper underlayer 2 is not particularly limited. Thus, the sliding component body 102 having the copper base layer 2 is formed. In the third step, the lead bronze alloy powder is applied onto the copper underlayer 2 and sintered, and then pressed with a roller or the like. As the lead bronze alloy, for example, an alloy containing 6 to 11 wt% of tin (Sn), 4 to 22 wt% of lead (Pb), and copper (Cu) as the balance can be used. Examples of JIS standard alloys include LBC2, LBC3, LBC4, and LBC5. In this way, the sliding component main body 103 on which the lead bronze alloy layer 3 as the bearing alloy layer is formed and deposited is obtained. The thickness of the lead bronze alloy layer 3 is not particularly limited, but is, for example, 0.2 to 1.5 mm.

  The fourth step is a step of further providing (depositing) the coating layer 4 on the lead bronze alloy layer 3. The coating layer 4 evaporates and scatters by heat during the gas soft nitriding process in which the lead in the lead bronze alloy layer 3 is normally performed at a high temperature, and covers the exposed surface 11 (second surface) of the steel back metal 1. It is intended to prevent wearing. The exposed surface 11 is a surface that is not covered with the lead bronze alloy layer 3, and includes, for example, the surface of the steel back metal 1 opposite to the lead bronze alloy layer 3. The coating layer 4 may be a copper plating layer 4a. In this case, the entire sliding part body 103 on which the lead bronze alloy layer 3 is formed is plated with copper, and then located on the surface of the lead bronze alloy layer 3. A portion other than the portion can be removed by polishing such as cutting or filing. Thus, the sliding component body 104a having the copper plating layer 4a on the surface of the lead bronze alloy layer 3 is formed. Although the thickness of the copper plating layer 4a is not specifically limited, For example, it is a thickness of 2-3 micrometers. The covering layer 4 may be a lead-free bronze layer 4b that does not contain lead, and can be formed by, for example, applying and sintering phosphor bronze powder. Although it does not specifically limit as phosphor bronze, For example, PBC2 (JIS specification) can be used. The thickness of the lead-free bronze layer 4b is not particularly limited, but is 0.2 to 0.3 μm, for example. Thus, the sliding component body 104b having the lead-free bronze layer 4b on the surface of the lead bronze alloy layer 3 is formed. Furthermore, the coating layer 4 may be the carbon-proof material layer 4c, and can be formed by applying a general carbon-proof material (carbon-proof agent). Thereby, the sliding component main body 104c which has the carbon-proof material layer 4c on the surface of the lead bronze alloy layer 3 is formed. As the carbon-proof material, a carburization-preventing paint obtained by dispersing a carburizing-proof material such as boron oxide in an organic solvent or an organic resin can be used. Also, as a carbon-proof material, a powder obtained by kneading and dispersing a thermoplastic resin such as polyethylene and inorganic additives such as silica (silicon dioxide) and alumina in boron oxide is used. Thus, the carbon-proof material layer 4c can be formed by heat-melting only on a desired portion. Furthermore, a commercially available tape-shaped carburizing inhibitor can be used.

The fifth process is a gas soft nitriding process, and the sliding component body 104 having the coating layer 4 on the surface of the lead bronze alloy layer 3 formed in the fourth process is gas soft nitrided. Even if the sliding component body 104 is heated to a high temperature during the gas soft nitriding treatment, the lead in the lead bronze alloy layer 3 does not evaporate or diffuse due to the coating layer 4, and the exposed surface of the steel back metal 1 11 is soft-nitrided well. The gas soft nitriding method may be a method generally used for steel, for example, a carburizing gas (RX gas) mainly composed of carbon monoxide (CO) at a high temperature of 520 to 580 ° C. The steel surface is nitrided and carbonized in a mixed gas atmosphere of ammonia and ammonia gas. The carburizing gas is an endothermic modified gas containing nitrogen (N ₂ ), hydrogen (H ₂ ) and the like in addition to carbon monoxide (CO). In this way, a sliding component body 105 is obtained in which the covering layer 4 is provided on the lead bronze alloy layer 3 and the compound layer 5 is formed on the exposed surface 11 of the back metal 1 by gas soft nitriding.

The sixth step is a step of removing the coating layer 4 by polishing such as cutting or filing. Since the coating layer 4 is necessary only during the gas soft nitriding treatment, it is necessary to remove this and expose the lead bronze alloy layer 3 as the sliding portion of the sliding component.
Thus, the lead bronze alloy layer 3 formed so as to cover the back metal 1 and the back metal 1 in which the compound layer 5 is formed on the exposed surface 11 not covered with the lead bronze alloy layer 3 by the gas soft nitriding treatment. A sliding part 106 is obtained.

  For example, when gas soft nitriding is performed at 580 ° C. for 90 minutes in a mixed gas atmosphere of ammonia gas and RX gas, lead is not evaporated or scattered by the coating layer 4, so that the surface of the steel back metal 1 is 8 to A compound layer with a thickness of 15 μm is obtained. This is the same thickness as the case where gas soft nitriding is performed under the same conditions on the steel material on which the lead bronze alloy layer 3 is not formed. The thickness is about 3 times larger than the thickness of 3 to 3.3 μm. Thus, by the manufacturing method of the present embodiment, a sliding part having a good quality gas soft nitride layer (compound layer) on the surface of the steel that is not covered with the sliding part made of the lead bronze alloy and the sliding part. It can be manufactured.

A second embodiment of the manufacturing method of the sliding component will be described with reference to the process diagram of FIG.
The second embodiment differs from the first embodiment in that the copper underlayer 2 is not formed in the second step, and a lead bronze layer is formed instead as the underlayer. That is, a lead bronze alloy layer is formed in direct contact with the steel member.

In this embodiment, first, in the second step, the lead bronze underlayer 7 is formed by firing lead bronze powder. Thereafter, in the third step, after the lead bronze underlayer 7 is rolled with a roller or the like, the lead bronze alloy powder is again applied and pressed on the lead bronze underlayer 7 and then sintered to be integrated with the lead bronze underlayer 7. A lead bronze alloy layer 3 'is formed. The third step may be omitted and the coating layer 4 may be formed directly on the surface of the lead bronze underlayer 7.
In addition to the effects of the first embodiment, the manufacturing method of this embodiment does not have a copper underlayer, and thus the manufacturing method is simple.

  A third embodiment will be described with reference to FIGS. 3 and 4. This embodiment relates to a sliding member (shoe) of a piston pump motor manufactured by applying the manufacturing method of the first and second embodiments.

  As shown in FIGS. 3A and 3B, the piston pump motor 20 includes a cylinder block 22 and a rotary shaft 26 splined to the cylinder block 22 in a housing 40. The rotating shaft 26 is rotatably supported by bearings 29a and 29b. Cylinders 22a are formed in the cylinder block 22 at predetermined angular intervals in the circumferential direction, and pistons 35 are slidably fitted into the cylinders 22a. A shoe 30 is provided at the end of the piston 35 so that it can swing relative to the piston 35 in accordance with the rotation of the cylinder block 22. A valve plate 18 having pressure oil intake / exhaust ports 18 a and 18 b is disposed in contact with the end face of the cylinder block 22. A swash plate 25 slidably contacting the shoe 30 is attached to the housing 40, and a shoe retainer 37 that holds the shoe 30 presses the shoe 30 against the swash plate 25. The shoe retainer 37 is swingably supported by the retainer guide 39.

  The cylinder block 22 is rotationally driven by the rotating shaft 26 while being pressed against the valve plate 18 by a spring 28 provided between the cylinder block 22 and the rotating shaft 26. By the rotation of the cylinder block 22, the piston 35 reciprocates along a stroke regulated by the swash plate 25 while revolving around the rotation shaft 26, and performs a pump operation via the intake / exhaust ports 18 a and 18 b of the valve plate 18.

  FIG. 4 is a process diagram illustrating a method for manufacturing the shoe 30. The shoe 30 is manufactured by applying the manufacturing method of the first and second embodiments, and has a sliding part 30a made of lead bronze that is in sliding contact with the swash plate 25. Detailed description of the steps already described in the first and second embodiments is omitted. Since the shoe 30 easily wears the surface of the substantially spherical ball portion 30b that contacts the piston 35 and the retainer contact portion 30c that contacts the shoe retainer 37, gas soft nitriding treatment is performed to improve wear resistance and fatigue resistance. Applied. Since the lead bronze alloy layer 3 is covered with the coating layer 4 during the gas soft nitriding treatment, a good gas soft nitriding treatment can be performed on the steel back metal 1 and the steel ball portion 30b.

  First, a sliding plate body 103 having a substantially flat steel back metal 1 and a lead bronze alloy layer 3 and a coating layer 4 formed on one surface of the back metal 1 is formed (first and second embodiments). Corresponding to the first to fourth steps of the form). Next, in the machining step, the surface of the back metal 1 opposite to the lead bronze alloy layer 3 is machined to form the retainer contact portion 30c and the ball connection portion 30d. Subsequently, in the welding process, the ball portion 30b is welded to the back metal 1 by welding. In some cases, the coating layer 4 may be formed on the lead bronze alloy layer 3 at this stage. Next, gas soft nitriding is performed, and the back metal 1 and the surface of the ball part 30b are gas soft nitrided to form the compound layer 5 (corresponding to the fifth step of the first and second embodiments). Subsequently, the coating layer 4 is removed (corresponding to the sixth step of the first and second embodiments). Finally, in the finishing process, drilling and end face processing are performed, and the shoe 30 is completed. A hole 30e (through hole) that penetrates the back metal 1 and the ball portion 30b and opens to the sliding portion is for guiding hydraulic pressure from a cavity inside the piston (see FIG. 3B), and the piston 35 When the oil is discharged from the port 18a, the contact surface pressure between the shoe 30 and the swash plate 25 is reduced by the hydraulic pressure.

  As described above, in this embodiment, it is possible to manufacture a sliding part made of lead bronze alloy and a piston pump shoe having high-quality gas soft nitriding on the steel surface not covered with the sliding part.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea. For example, the present invention can also be used for providing a lead bronze layer on the surface of the cylinder block 22 that is in sliding contact with the valve plate 18 and gas soft nitriding a part of the other surface of the cylinder block 22.

  The present invention can be applied to a sliding part having a sliding part made of lead bronze alloy and a steel surface not covered by the sliding part.

Process drawing which shows 1st embodiment of the manufacturing method of a sliding component. Process drawing which shows 2nd embodiment of the manufacturing method of a sliding component. (A) Sectional drawing which shows the piston pump motor which has a shoe to which this invention is applied, (b) Sectional drawing which shows the shoe to which this invention is applied. Process drawing which shows the manufacturing process of the shoe to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Back metal 2 Copper base layer 3, 3 'Lead bronze alloy layer 4 Coating layer 4a Copper plating layer 4b Lead free bronze layer 4c Carbide-proof material layer 5 Compound layer 7 Lead bronze base layer 9 Sliding part surface (1st surface)
11 Exposed surface (second surface)
18 Valve plate 18a, 18b Port 20 Piston pump motor 22 Cylinder block 25 Swash plate 26 Rotating shaft 30 Shoe 30a Sliding part 30b Ball part 30c Retainer contact part 30d Ball connection part 30e Hole 35 Piston 37 Shoe retainer 39 Retainer guide

Claims (8)

A method of manufacturing a sliding component having a sliding portion,
Forming a lead bronze alloy layer functioning as a sliding portion so as to cover the first surface of the steel member;
Forming a coating layer on the lead bronze alloy layer;
Gas soft nitriding the second surface of the steel member not covered with the lead bronze alloy layer;
Removing the coating layer;
A method for manufacturing a sliding component, comprising: A method of manufacturing a sliding component having a sliding portion,
Forming a copper underlayer on the first surface of the steel member;
Forming a lead bronze alloy layer functioning as a sliding portion on the copper underlayer;
Forming a coating layer on the lead bronze alloy layer;
Gas soft nitriding the second surface of the steel member not covered with the lead bronze alloy layer;
Removing the coating layer;
A method for manufacturing a sliding component, comprising:   The method for manufacturing a sliding component according to claim 1, wherein the coating layer is a copper plating layer formed by copper plating.   The method for manufacturing a sliding component according to claim 1, wherein the coating layer is a lead-free bronze layer that does not contain lead.   The method for manufacturing a sliding component according to claim 1, wherein the coating layer is a carbon-proof material layer formed by applying a carbon-proof material. A method of manufacturing a sliding component having a sliding portion,
Forming a lead bronze alloy layer functioning as the sliding portion on the first surface of the steel back metal;
Welding a steel ball to a steel back metal;
Forming a coating layer on the lead bronze alloy layer;
Gas soft nitriding the surface of the steel back metal and the surface of the ball part not covered with the lead bronze alloy layer;
Removing the coating layer;
A process of forming a through-hole penetrating the back metal and the ball portion and opening in the sliding portion;
A method for manufacturing a sliding component, comprising: A sliding part having a sliding part,
A steel plate with a substantially flat plate shape;
A substantially spherical ball portion;
A sliding part made of lead bronze alloy formed so as to cover the first surface of the steel back metal;
A through-hole penetrating the back metal and the ball portion, and further opening in the sliding portion;
With
A sliding part, wherein the second surface of the back metal and the surface of the ball part not covered with the sliding part made of lead bronze alloy are subjected to gas soft nitriding treatment.   A piston pump motor comprising the sliding component according to claim 7.

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