WO2013022094A1

WO2013022094A1 - Sliding nut, sliding bearing for compressor, and cradle guide

Info

Publication number: WO2013022094A1
Application number: PCT/JP2012/070524
Authority: WO
Inventors: 安田　健; 靖史大橋; 福澤　覚; 石井　卓哉
Original assignee: Ntn株式会社
Priority date: 2011-08-11
Filing date: 2012-08-10
Publication date: 2013-02-14

Abstract

Provided is a sliding nut for a sliding screw device, a sliding screw device, and so on that are easy to manufacture and have outstanding sliding properties, including seize resistance and abrasion resistance, even under high-load conditions. A sliding nut in a sliding screw device moves relative to the screw shaft while sliding along the screw shaft as the screw shaft rotates. A nut body (73a) is made of sintered metal, and a thin resin layer (73b), made of a resin composition having a synthetic resin such as aromatic polyether ketone resin as a base resin, is formed by injection molding and serves as a thread groove section in an internally threaded surface on the body of the nut for screwing together with the screw shaft.

Description

Sliding nuts, plain bearings for compressors, and cradle guides

The present invention relates to a sliding nut of a sliding screw device, a sliding bearing for a compressor, and a cradle guide, which are members obtained by thinly molding a resin layer on a sintered metal part. Furthermore, the present invention relates to a sliding screw device using the sliding nut, a compressor using the sliding bearing for the compressor, and a variable displacement axial piston pump using the cradle guide.

¡Slide screw devices that convert rotational motion into linear motion have the advantage that they can be designed more compactly than ball screw devices, and are often used in industrial machine feeders and positioning devices. Conventionally, a sliding screw device using a resin nut has been developed for maintenance-free purposes.

For example, the screw groove portion (or the entire nut) screwed into the screw shaft is not made of polyphenylene sulfide resin and at least 280 ° C. with a tetrafluoroethylene resin. There has been proposed a resin nut formed from a polyphenylene sulfide resin composition obtained by blending molten organic resin powder (see Patent Document 1). The screw shaft and a nut that moves relatively while sliding on the shaft of the screw shaft as the screw shaft rotates, and at least the female screw portion of the nut has an aromatic polyimide resin powder. A sliding screw device in which a body coating film is formed has been proposed (see Patent Document 2).

Moreover, as a thing which consists of a metal part and a resin part, for example, it is a nut with a flange that is screwed to a screw shaft and moves relative to the screw shaft in the axial direction. The outer periphery including the flange is made of metal, and the screw shaft A flanged nut has been proposed in which an inner peripheral portion to be screwed to the inner peripheral portion is formed of a lubricating resin, and a means for preventing rotation and retaining between the outer peripheral portion and the inner peripheral portion is provided (patent) Reference 3).

In addition, as a method for manufacturing a resin nut, a fixed mold having a mold surface that molds one end surface of the resin nut, or one end surface thereof and the vicinity thereof, and a cavity that molds the remaining outer surface of the resin nut are used. In contrast, an injection mold having a movable mold movable in the axial direction and a core pin provided on the movable mold and formed with a spiral groove for forming a thread groove on the outer diameter surface is used. There has been proposed a manufacturing method in which a resin nut is formed by filling a molten resin and then opening a mold and rotating a core pin (see Patent Document 4).

A compressor used for an air conditioner or the like has a rotating member for driving the compression mechanism, and the rotating member is supported by a bearing. Conventionally, for example, in a compressor provided with a sliding bearing that rotatably supports this rotating member, a material in which a fluororesin is coated on the base material through a porous metal having a solid lubricating function has been proposed as the sliding bearing. (See Patent Document 5). This sliding bearing is formed by coating the surface of a flat plate member with a fluororesin via a bronze sintered layer that is a porous metal and bending it into a cylindrical shape.

In Patent Document 5, since a sliding bearing is used as a bearing that supports a rotating member, the number of parts is reduced as compared with the case where a rolling bearing is used, and the cost can be reduced. In addition, the interposition of the fluororesin and the porous metal makes it difficult for the sliding contact portion between the rotating member and the sliding bearing to be worn, thereby extending the life of the compressor. Since the fluororesin is coated on the base material through the porous metal, the fluororesin is hardly peeled off from the base material side when a part of the fluororesin enters the hole portion of the porous metal.

The sliding bearing that supports the rotating member for driving the compression mechanism has precise rotation accuracy and stably obtains low rotational torque, so it has excellent load resistance and creep resistance, and is dimensioned even under high surface pressure. It is required that it does not change. As the sliding bearing used for the same application, in addition to Patent Document 5, for example, a multilayer bearing disclosed in Patent Document 6 and Patent Document 7 can be cited. The bearing (sliding member) of Patent Document 6 has a surface layer made of a polyether ether ketone (PEEK) resin on a porous sintered layer on a back metal layer. In the cylindrical bearing bush in Patent Document 7, the bronze sintered layer and the synthetic resin composition filled and coated on this layer are exposed on the inner peripheral surface thereof.

As a variable displacement piston pump used as a hydraulic pressure generation source of a hydraulic circuit, for example, the structure of a so-called cradle type pump (hereinafter also simply referred to as “pump”) is well known. In the cradle type pump, a cylinder block that accommodates a piston is integrally rotated together with a rotating shaft, and the cradle is slidably contacted with the cradle guide and supported so as to be inclined with respect to the rotating shaft. It contacts the inclined surface of the cradle via the connected shoe. Therefore, the piston reciprocates with a stroke defined according to the inclination angle of the cradle with the rotation of the rotating shaft, and has a pump action. The discharge capacity of the pump due to the stroke difference can be constantly changed by controlling the inclination angle of the cradle with respect to the rotation axis by hydraulic pressure or the like.

However, when a cradle made of an aluminum material (including an aluminum alloy) is held in sliding contact with a cradle guide made of the same aluminum material, both of them are used in a state where the tilt angle with respect to the rotation axis of the cradle is constantly controlled by hydraulic pressure or the like. Causes sliding contact wear and causes problems such as seizure. For this reason, a means has been adopted in which a synthetic resin thrust bushing is interposed between the cradle and the cradle guide.

For example, as a thrust bush serving as a cradle guide, a metal thrust bush having a sliding surface provided with a resin film, a nylon (polyamide resin), a polyacetal resin, a polytetrafluoroethylene (hereinafter referred to as PTFE) resin, or the like. A thrust bush made of a dynamic resin is known (see Patent Document 8).

At least one of the cradle or the cradle guide made of an aluminum material is coated with a fluorine resin such as an ethylene-tetrafluoroethylene copolymer (ETFE) resin, a tetrafluoroethylene-hexafluoropropylene copolymer (FEP) resin, or a PTFE resin. An applied variable displacement piston pump is also known (see Patent Document 9).

Further, as a thrust bush serving as a cradle guide, there are known a thrust bush in which a copper-based sintered film is formed on the surface of an iron base, and a thrust bush in which a resin film is further applied to the surface of the sintered film (see Patent Document 10). ).

JP 2003-239932 A JP 2004-204989 A JP 2006-138405 A JP 2004-25527 A JP 2002-349437 A JP-A-8-210357 JP 2007-205254 A Utility Model Registration No. 2559510 Japanese Unexamined Patent Publication No. 08-334081 Utility Model Registration No. 2584135

However, although the resin nut of Patent Document 1 can be used without lubrication, it is difficult to use at a high load (high surface pressure) of 1 kPa or more. On the other hand, although the sliding screw device of Patent Document 2 can be used even at a high load of 1 kPa or more, it is not easy to form a powder coating film of an aromatic polyimide resin uniformly on the female screw portion of the nut. Further, depending on the use conditions, there is a possibility that the adhesion (shear adhesion strength) between the powder coating film and the nut is not sufficient.

Further, in the nut with flange of Patent Document 3, the outer peripheral part of the nut is made of metal, but the inner peripheral part including the female screw part is made of a synthetic resin. This is equivalent to the resin nut No. 1 and the female thread portion may be destroyed when used under a high load.

The manufacturing process of the sliding bearing described in Patent Document 6 is as follows. A porous bronze layer is formed by spreading and sintering lead bronze powder to a thickness of 0.3 mm on a 0.8 mm thick back metal plated with copper. A sheet of a resin composition containing PEEK resin as a main component is superimposed on the porous sintered layer and pressed between rolls to impregnate and coat the resin composition, thereby forming a multilayer having a thickness of 1.5 mm. . After cutting this, the resin composition side is turned to the inside, for example, it is curved and formed into a cylindrical shape having an inner diameter of 20 mm and a width of 20 mm, and then finished by turning or grinding so that the inner diameter becomes a perfect circle. The same applies to the sliding bearings in Patent Document 5 and Patent Document 7, such as bending into a cylindrical shape (cylindrical shape) after forming and cutting the multilayer.

For this reason, as shown in FIG. 3 of Patent Document 7, a cutting portion remains in one place in the circumferential direction of the sliding bearing, and the shape in the vicinity of the cutting portion becomes distorted even if processed by a lathe or a polishing machine. There is a problem. Further, in the case of lathe processing, there is a problem in that the cutting tool is heavily worn by the cutting tool and the required time is increased. Also in the case of polishing, since the object to be polished is a resin, there is a problem that the grindstone is frequently clogged, and the required time is also increased.

Normally, when the cradle contacts the cradle guide at a high surface pressure of about 30 MPa and always slides, the cradle guide (thrust bush) described in Patent Document 8 cannot satisfy the load resistance due to the resin film. There's a problem. The problem regarding the load resistance in this application is that a fluororesin coating such as PTFE resin described in Patent Document 9 is formed on the surface of a cradle guide made of aluminum, or an iron base material described in Patent Document 10 It can be improved if a fluororesin coating is formed on the surface of the film via a copper-based sintered film. However, in that case, the wear resistance and the low friction characteristics were not sufficient.

Also, when forming a coating (coating) layer on a steel plate, spraying, drying, firing, etc. are necessary. Further, it is necessary to perform processing with a lathe or a polishing machine after the formation. For this reason, a manufacturing cost becomes high.

The present invention has been made to cope with these problems. That is, an object is to provide a sliding nut and a sliding screw device of a sliding screw device that are easy to manufacture and have excellent sliding characteristics such as seizure resistance and wear resistance even under high load conditions. In addition, it is easy to manufacture, has high dimensional accuracy, is excellent in heat resistance, low friction, wear resistance, load resistance, and creep resistance, and can stably obtain low rotational torque. It is an object of the present invention to provide a sliding bearing for a compressor and a compressor provided with the sliding bearing for the compressor. Also, a cradle guide for a variable displacement axial piston pump that can satisfy all of the load resistance, wear resistance, and low friction characteristics of 30 MPa or more while being easy to manufacture and low cost, and a variable capacity using the cradle guide The purpose is to provide a type axial piston pump.

The sliding nut of the present invention is a sliding nut that moves relatively while sliding on the shaft of the screw shaft as the screw shaft rotates in the sliding screw device, and the sliding nut is a nut The main body is made of a sintered metal, and a resin layer of a resin composition having a synthetic resin as a base resin is formed as a screw groove portion on the surface of a female screw portion screwed into the screw shaft of the nut main body. . In particular, the resin layer is a resin layer that is injection-molded over the nut body. The resin layer has a thickness of 0.1 to 1.5 mm.

The synthetic resin is an aromatic polyether ketone resin. The resin composition is characterized in that an aromatic polyetherketone resin is used as a base resin, and a fibrous filler is contained in the resin. Further, the fibrous filler is a fibrous filler having an average fiber length of 0.02 to 0.2 mm.

The sintered metal of the nut body has a theoretical density ratio of 0.7 to 0.9.

The resin composition is a resin composition having a melt temperature of 50 to 200 Pa · s at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ .

In the case where the resin composition uses an aromatic polyetherketone resin as a base resin and contains a fibrous filler, 5 to 30 volumes of carbon fiber is used as the fibrous filler with respect to the entire resin composition. And 1 to 30% by volume of PTFE resin. In particular, the carbon fiber is a PAN-based carbon fiber.

The sliding screw device of the present invention includes a screw shaft and a sliding nut that moves relatively while sliding on the shaft of the screw shaft as the screw shaft rotates. The above-mentioned sliding nut of the present invention is characterized by the above. The slide screw device is lubricated with oil or grease.

A sliding bearing for a compressor according to the present invention is a sliding bearing for a compressor that rotatably supports a rotating member for driving a compression mechanism of the compressor, and the sliding bearing is formed on a sintered metal substrate, A sliding surface of a resin layer made of a resin composition comprising an aromatic polyetherketone resin as a base resin, the resin layer being 0.1 to 0.7 mm on the surface of the sintered metal base material; It is characterized in that it is provided integrally by being laminated by injection molding with a thickness.

The resin composition includes a fibrous filler, and in the resin layer, the fibrous filler is oriented so that the length direction of the fiber intersects 45 to 90 degrees with respect to the sliding direction of the sliding bearing. It is characterized by being.

The sliding bearing is a bearing that supports the rotating member in the radial direction (radial sliding), and is arranged to pressure-isolate the internal space in the housing of the compression mechanism.

The sliding bearing is a bearing that supports the rotating member in a thrust direction (thrust sliding), and is disposed on a side that receives a compression reaction force generated in the compression mechanism via the rotating member. To do.

The compressor of the present invention is characterized by comprising the above-described slide bearing of the present invention that rotatably supports a rotating member for driving the compression mechanism.

A cradle guide according to the present invention is a cradle guide that is slidably contacted with a cradle that adjusts a piston stroke in a variable displacement axial piston pump and holds the cradle so that the cradle can swing. And a resin layer made of a resin composition having an aromatic polyetherketone resin as a base resin, and the resin layer has a surface in contact with at least the cradle of the sintered metal member. It has a thickness of 1 to 0.7 mm and is integrally provided by injection molding.

The resin composition includes a fibrous filler, and in the resin layer, the fibrous filler is oriented so that the length direction of the fiber intersects 45 to 90 degrees with respect to the sliding direction of the cradle guide. It is characterized by being.

The sintered metal member is a cradle guide body. As another aspect, the cradle guide has a cradle guide main body made of molten metal, and the sintered metal member is installed on the cradle guide main body.

A variable displacement axial piston pump according to the present invention includes the cradle guide according to the present invention.

In the sliding nut of the present invention, the nut body is made of a sintered metal, and a resin layer of a resin composition having a synthetic resin as a base resin is formed as a thread groove on the surface of the female thread that is screwed onto the screw shaft of the nut body. As a result, the resin layer bites into the pores (surface irregularities) of the sintered metal, and the resin layer and the nut body can be firmly adhered. Moreover, it is excellent in the mechanical strength, heat dissipation characteristics, and durability of the tooth base of the female thread portion of the nut body. As a result, the real contact area on the friction surface is reduced, the frictional force and frictional heat generation are reduced, and there is an advantage that wear is reduced and the increase in the friction surface temperature is suppressed.

Since the resin layer that is the thread groove portion is a resin layer that is injection molded over the nut body, it can be easily and accurately formed on the surface of the female thread portion. Further, the resin layer deeply penetrates into the pores on the surface of the sintered metal during injection molding, the true bonding area is increased, and the adhesion strength between the resin layer and the nut body is improved. Further, there is no gap in the joint surface between the resin layer and the internal thread portion (sintered metal), and the heat of the resin layer is easily transmitted to the nut body.

Since the resin layer is thin with a layer thickness of 0.1 to 1.5 mm, the heat generated by frictional heat easily escapes from the friction surface to the nut body, is difficult to store heat, has high load resistance, and can be deformed even under high surface pressure. Becomes smaller.

Since the base resin of the resin composition forming the resin layer is an aromatic polyether ketone resin, it is excellent in load resistance, heat resistance, low friction characteristics, and wear resistance characteristics.

Since the resin composition for forming the resin layer contains a fibrous filler in an aromatic polyether ketone resin, it is excellent in friction and wear characteristics and creep resistance characteristics. In particular, since the fibrous filler is a fibrous filler having an average fiber length of 0.02 to 0.2 mm, the resin layer is excellent in friction and wear characteristics and creep resistance, and has a female thread portion (screw groove portion). There is no hindrance to precision molding.

Since the sintered metal of the nut main body has a theoretical density ratio of 0.7 to 0.9, it has a required denseness while ensuring unevenness of the surface to obtain adhesion to the resin layer, and the nut The thermal conductivity of the main body can be secured.

Since the resin composition is a resin composition having a melt temperature of 50 to 200 Pa · s at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ , 0.1 to 1.5 mm is formed on the surface of the nut body made of sintered metal. Thin insert molding can be performed smoothly.

In the case where the resin composition uses an aromatic polyetherketone resin as a base resin and contains a fibrous filler, 5 to 30 volumes of carbon fiber is used as the fibrous filler with respect to the entire resin composition. %, And PTFE resin is contained in an amount of 1 to 30% by volume. Therefore, even under high PV conditions, deformation and wear of the resin layer, damage to the counterpart material are small, and resistance to oil and the like is high. In particular, since the carbon fiber is a PAN-based carbon fiber, the elastic modulus of the resin layer is increased, and deformation and wear of the resin layer are reduced. Furthermore, the true contact area of the friction surface is reduced, and frictional heat generation is reduced.

The sliding screw device of the present invention comprises a screw shaft and the sliding nut of the present invention that moves relatively while sliding on the shaft of the screw shaft as the screw shaft rotates. Although it is easy and inexpensive, it has excellent sliding characteristics such as seizure resistance and wear resistance even under high load conditions. Further, by being lubricated with oil or grease, it is possible to withstand a high load and to ensure high-precision rotational stability.

The sliding bearing for a compressor of the present invention has a sliding surface of a resin layer made of a resin composition having an aromatic polyether ketone resin as a base resin on a sintered metal base material, so that it has heat resistance and low friction. There is an advantage that it becomes a slide bearing for a compressor excellent in heat resistance and wear resistance. Further, since the resin layer is integrally provided by injection molding on the surface of the sintered metal base material with a thickness of 0.1 to 0.7 mm, it is excellent in load resistance and creep resistance. It is possible to stably obtain a low rotational torque without changing the dimensions even under high surface pressure. Furthermore, the resin layer is provided integrally with the surface of the sintered metal base material by injection molding, that is, the resin metal layer is formed by injection molding by inserting the sintered metal base material into the mold. Unlike conventional multi-layer bearings, there is no need to cut or bend the lathe with a lathe or grinding machine after multi-layer formation and cutting, and manufacturing is easy and low cost, but the sliding surface has high dimensional accuracy. It becomes.

Since the resin composition contains a fibrous filler, the heat resistance, wear resistance, load resistance, and creep resistance of the resin layer can be further increased. Further, the fibrous filler in the resin layer is oriented so that the length direction of the fiber intersects 45 to 90 degrees with respect to the sliding direction of the sliding bearing. Aggressiveness to the mating material surface can be reduced, and fluctuations in rotational torque can be prevented.

The sliding bearing for a compressor of the present invention has the same bearing size as that of a conventional sliding bearing for a compressor, but is excellent in wear resistance, low friction, dimensional stability, and the like. For this reason, it can be used suitably for the radial sliding bearing which supports the rotating member of a compressor in a radial direction. In addition, there is no cutting part like a conventional sliding bearing for a compressor, and the outer peripheral surface and sliding surface of the bearing can be formed with high accuracy, so that the fitting clearance with the support shaft can be reduced, and the good Sealing performance can be demonstrated. For this reason, it is also possible to arrange | position the internal space in the housing of a compressor so that it may isolate in pressure, without providing a sealing member.

¡Although it has the same bearing size as the conventional plain bearing for compressors of the present invention, it is excellent in wear resistance, low friction, dimensional stability and the like. For this reason, it can be used conveniently also as a thrust slide bearing which supports the rotation member of a compressor in a thrust direction.

The compressor of the present invention is a compressor provided with a sliding bearing that rotatably supports a rotating member for driving a compression mechanism, and the sliding bearing for a compressor of the present invention is adopted as this sliding bearing. The compressor can be excellent in energy saving and long life.

The cradle guide of the variable capacity type piston pump of the present invention uses, as a base resin, a sintered metal member and an aromatic polyetherketone resin formed on the surface of the sintered metal member at least in contact with the cradle. Therefore, there is an advantage that the cradle guide is excellent in heat resistance, low friction and wear resistance. In addition, since the resin layer is integrally formed by injection molding on the surface of the sintered metal member with a thickness of 0.1 to 0.7 mm, it is excellent in load resistance and creep resistance, It is possible to stably obtain a low torque without changing dimensions even under surface pressure. As a result, there is an advantage that the cradle guide can be used for a long period of time by satisfying all of the load resistance, wear resistance and low friction characteristics even in a high-pressure sliding state of 30 MPa or more. Further, the resin layer is integrally provided on the surface of the sintered metal member by injection molding, that is, the resin layer is formed by injection molding by inserting the sintered metal member into the mold. There is no need to form a coating layer (spraying, drying, firing, etc.) on a steel plate like a cradle guide, and there is no need for processing with a lathe or a polishing machine. The sliding surface has high dimensional accuracy.

Since the resin composition contains a fibrous filler, the heat resistance, wear resistance, load resistance, and creep resistance of the resin layer can be further increased. Further, in the resin layer, the fibrous filler is oriented so that the length direction of the fiber intersects 45 to 90 degrees with respect to the sliding direction of the cradle guide. Aggressiveness to the mating material surface can be reduced, and fluctuations in sliding torque can be prevented.

Since the sintered metal member is a cradle guide body, the number of parts is small, the structure is simple, and the manufacturing cost is low.

Further, as another aspect, further comprising a cradle guide body made of molten metal, by installing the sintered metal member in the cradle guide body, while ensuring high mechanical strength as a whole cradle guide, The above-mentioned effect can be obtained by using a sintered metal member and a thin-walled injection molded resin layer. Moreover, in this aspect, since the conventional cradle guide main body can be used, a design change etc. are unnecessary and it can prevent a cost increase.

Since the variable displacement axial piston pump of the present invention includes the cradle guide of the present invention, it is possible to precisely control the tilt angle of the cradle, thereby performing a precise hydraulic control operation, etc. Become a high pump.

It is a perspective view of a slide screw device. It is an axial sectional view of a sliding nut. It is sectional drawing which shows 1st Embodiment of the compressor using the sliding bearing for compressors. It is the perspective view and sectional drawing which show an example of the sliding bearing for compressors (radial sliding bearing). It is the perspective view and sectional drawing which show the other example of the sliding bearing for compressors (radial sliding bearing). It is sectional drawing which shows 2nd Embodiment of the compressor using the sliding bearing for compressors. It is the perspective view and sectional drawing which show an example of the sliding bearing for a compressor (thrust sliding bearing). It is sectional drawing which shows 3rd Embodiment of the compressor using the sliding bearing for compressors. It is sectional drawing which shows 4th Embodiment of the compressor using the sliding bearing for compressors. It is a longitudinal section of a variable capacity type axial piston pump using a cradle guide of the present invention. It is a perspective view which shows an example of a cradle guide. It is a perspective view which shows the other example of a cradle guide. It is a disassembled perspective view of the cradle guide of FIG. It is a perspective view which shows the other example of a cradle guide. It is sectional drawing of a cradle guide.

Now, the sliding nut and the sliding screw device of the present invention will be described.

An embodiment of the sliding screw device of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a sliding screw device, and FIG. 2 is an axial sectional view of a sliding nut. The sliding screw device 71 of the present invention is composed of a screw shaft 72 and a sliding nut 73 of the present invention which is screwed into a screw groove of the screw shaft 72 and moves relatively while sliding on the screw shaft. Is done. The rotational movement of the screw shaft 72 is converted into the linear movement of the sliding nut 73. In addition, by rotating the sliding nut 73 at the same position, it is possible to apply a linear motion to the screw shaft 72.

As the screw shaft 72, stainless steel, carbon steel, or the like, or a metal shaft such as an iron-based metal or aluminum alloy obtained by applying zinc plating, nickel plating, steel chrome plating, or the like, or a resin shaft such as polyimide resin or phenol resin. Can be used. Corrosion-resistant metals such as stainless steel and aluminum alloys or resins are preferred because they do not generate rust, and are also suitable from the point that rust prevention treatment can be omitted. In the present invention, corrosion-resistant metals that can ensure dimensional accuracy and have excellent durability are most preferable.

The screw shaft 72 can be used without lubrication. In the case where low friction is more important than maintenance free, a lubricant such as oil or grease may be used for the sliding portion between the screw shaft 72 and the sliding nut 73. In this case, it is preferable to take a measure so as to suppress the aggressive wear by forming a linear groove in the axial direction of the female thread portion of the sliding nut so as to hold the wear powder there.

As shown in FIG. 2, the sliding nut has a nut body 73a made of sintered metal, and a synthetic resin, which will be described later, is used as a base resin on the surface of a female thread portion that is screwed onto a screw shaft in the nut body 73a. A resin layer 73b of the resin composition is formed. The female thread portion is a part of the nut main body 73a and is formed on the inner diameter portion of the nut main body 73a, and the resin layer 73b, which is a thread groove portion, is formed so as to cover the surface of the female thread portion. The resin layer 73b, which is a screw groove, is in direct sliding contact with the screw shaft 72 (see FIG. 1). In addition, the resin layer 73b should just be formed in the surface of the internal thread part at least, and may be formed in the other surface of the nut main body 73a.

The resin layer 73b bites into the pores of the sintered metal of the nut body 73a, so that the resin layer 73b and the nut body 73a are firmly attached. In particular, when injection molding is performed by insert molding, the resin layer 73b deeply bites into the irregularities on the surface of the nut body (sintered metal) during injection molding, and the true bonding area increases, so the resin layer 73b and the nut body 73a The adhesion strength with is improved. Further, the true bonding area between the resin layer 73b and the nut main body 73a is increased, and there is no gap in the bonding surface between the resin layer and the internal thread portion (sintered metal), so that the heat of the resin layer 73b is easily transmitted to the nut main body 73a. .

The thread shape is, for example, a triangular screw such as a miniature screw, metric coarse screw, metric fine screw, unified coarse screw, or unified fine screw, a trapezoidal screw such as a 29 degree trapezoidal screw or a metric trapezoidal screw, or a round screw. Any screw shape may be applied. Further, it may be a single thread, a double thread, or a multiple thread.

As the material of the sintered metal constituting the nut body, iron-based, copper-iron-based, copper-based, stainless-based materials, and the like can be given. Since adhesion between the resin layer and the nut body can be enhanced, it is preferable to use a sintered metal containing iron as a main component, and further an iron-based sintered metal having a copper content of 10% by weight or less. In addition, since copper is inferior to adhesiveness (adhesiveness) with resin rather than iron, 10 weight% or less of copper content is preferable. More preferably, the copper content is 5% by weight or less.

If the sintered metal that makes up the nut body contains oil or other oil, oil residue that decomposes and gasifies during injection molding of the resin layer is present at the interface. May deteriorate. Therefore, it is preferable to use a sintered metal not impregnated with oil for the nut body. Moreover, when using oil in the process of shaping | molding or re-pressing (sizing) of a sintered metal, it is preferable to set it as the non-oil-containing sintered metal which removed oil by solvent washing etc.

In the nut body, the density of the sintered metal (sintered body) is preferably a theoretical density ratio of the material of 0.7 to 0.9. The theoretical density ratio of the material is the ratio of the density of the nut body when the theoretical density of the material (density when the porosity is 0%) is 1. If the theoretical density ratio is less than 0.7, the strength of the sintered metal is lowered, and the sintered metal may be broken by the injection molding pressure at the time of insert molding. When the theoretical density ratio exceeds 0.9, the unevenness is reduced, so that the surface area and the anchor effect are lowered, and the adhesion with the resin layer is lowered. More preferably, the theoretical density ratio of the materials is 0.72 to 0.84.

Sintered metal with iron as its main component is an effect that removes oil and deposits adhering to the sintered surface or penetrating into the sintered body unintentionally during the molding or re-pressing (sizing) process by applying steam treatment Therefore, variation in adhesion with the resin layer is small and stable. Moreover, rust prevention can also be provided to the nut body. The conditions for the steam treatment are not particularly limited, but a method of spraying steam heated to about 500 ° C. is common.

As a method for forming the resin layer, there are coating by dipping and injection molding (insert molding). Moreover, you may interpose an adhesive agent in a joint surface. Considering screw dimensional accuracy, adhesion between the resin layer and the nut body, ease of manufacturing, etc., there is a method of injection molding over the nut body, that is, injection molding in which the resin layer is insert-molded to the nut body. preferable.

The thickness of the resin layer is preferably 0.1 to 1.5 mm. The thickness of the resin layer is the thickness of the surface portion that does not enter the nut body of the sintered metal. If the resin thickness is less than 0.1 mm, insert molding is difficult. In addition, durability during long-term use, that is, life may be shortened. On the other hand, if the resin thickness exceeds 1.5 mm, sink marks may occur and dimensional accuracy may be reduced. Further, heat due to friction is difficult to escape from the friction surface to the nut body side, and the friction surface temperature becomes high. In addition, the amount of deformation due to the load increases, the true contact area on the friction surface also increases, the frictional force and frictional heat generation increase, and the seizure resistance may decrease.

¡In consideration of heat dissipation of the frictional heat to the nut body, the resin thickness is more preferably 0.2 to 0.7 mm. A sliding nut with high dimensional accuracy is formed by insert molding a thin resin layer (0.1 to 1.5 mm) on the surface of the internal thread of the nut body made of sintered metal with high dimensional accuracy. Can do.

The resin composition forming the resin layer is based on a synthetic resin. The synthetic resin is preferably a synthetic resin that can be injection-molded and has excellent lubricating properties. Further, a synthetic resin having high heat resistance is preferable so that it can be used in a part having a high atmospheric temperature. Examples of such synthetic resins include aromatic polyether ketone (PEK) resins, polyacetal (POM) resins, polyphenylene sulfide (PPS) resins, injection-moldable polyimide resins, polyamide imide (PAI) resins, polyamides ( PA) resin, injection-moldable fluororesin, and the like. Each of these synthetic resins may be used alone or may be a polymer alloy in which two or more kinds are mixed.

Among these synthetic resins, it is preferable to use a PEK resin. By using PEK resin as the base resin of the resin composition that forms the resin layer, the continuous use temperature is 250 ° C, and it has excellent heat resistance, oil / chemical resistance, creep resistance, and friction and wear characteristics. It becomes the sliding nut of the screw device. In addition, PEK-based resin has high toughness, high mechanical properties at high temperatures, and excellent fatigue resistance and impact resistance. Therefore, from the nut body made of sintered metal due to frictional force, impact, vibration, etc. during use There is no worry of peeling.

Examples of the PEK resin include polyether ether ketone (PEEK) resin, polyether ketone (PEK) resin, and polyether ketone ether ketone ketone (PEKEKK) resin. Examples of commercially available PEEK resins that can be used in the present invention include: Victorex Corporation: PEEK (90P, 150P, 380P, 450P, 90G, 150G, etc.), Solvay Advanced Polymers Corporation: KetaSpire (KT-820P, KT-880P) Etc., manufactured by Daicel Degussa, Inc .: VESTAKEEEP (1000G, 2000G, 3000G, 4000G, etc.). Examples of the PEK resin include Victrex-HT manufactured by Victrex, and examples of the PEKKK resin include Victrex-ST manufactured by Victrex.

The resin composition forming the resin layer preferably has a melt viscosity of 50 to 200 Pa · s at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ . When the melt viscosity is within this range, a thin insert molding of 0.1 to 1.5 mm can be smoothly performed on the surface of the nut body made of sintered metal. If the melt viscosity is less than the predetermined range or exceeds the predetermined range, it is not easy to ensure accurate moldability. By making thin insert molding possible and making post-processing after insert molding unnecessary, manufacturing becomes easy and manufacturing costs can be reduced.

In the case of a resin composition having a PEK resin as a base resin, in order to set the melt viscosity at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ to 50 to 200 Pa · s, the melt viscosity under these conditions is 150 Pa · s or less. It is preferable to employ a PEK resin. Examples of such PEK-based resins include Victorex Corporation: PEEK (150P, 90P, 150G, 90G), Solvay Advanced Polymers Corporation: KetaSpire (KT-880P), and the like. In particular, in order to obtain a resin thickness of 0.2 to 0.7 mm, it is preferable to use a PEK-based resin having a melt viscosity of 130 Pa · s or less under the above conditions, such as PEEK (90P, 90G) manufactured by Victrex. Can be illustrated.

The resin composition forming the resin layer uses the PEK-based resin as a base resin, and fiber fillers such as glass fiber, carbon fiber, aramid fiber, and whisker, PTFE resin, graphite, molybdenum disulfide, and disulfide. Solid lubricants such as tungsten and inorganic fillers such as calcium carbonate, calcium sulfate, mica and talc can be blended. By blending these, the creep resistance characteristics, the friction and wear characteristics with no lubrication or oil lubrication can be further improved. Specifically, the fibrous filler, the inorganic solid lubricant (graphite, molybdenum disulfide, etc.), and the inorganic filler have an effect of reducing the molding shrinkage of the PEK resin. Therefore, there is an effect of suppressing the internal stress of the resin layer at the time of insert molding with the nut body. Further, the solid lubricant is non-lubricated and has low friction even under the condition where the lubricating oil is dilute, thereby improving the seizure property.

The average fiber length of the fibrous filler is preferably 0.02 to 0.2 mm. If the thickness is less than 0.02 mm, a sufficient reinforcing effect cannot be obtained, and the creep resistance and wear resistance may be inferior. When the thickness exceeds 0.2 mm, the ratio of the fiber length to the layer thickness of the resin layer becomes large, so that the thin formability is inferior. In particular, when insert molding is performed with a resin thickness of approximately 0.1 to 1.5 mm, thin-wall moldability is hindered if the fiber length exceeds 0.2 mm. In order to further improve the stability of thin-wall molding, an average fiber length of 0.02 to 0.1 mm is more preferable.

Among the fibrous fillers, it is preferable to use carbon fibers. Carbon fiber has a strong orientation in the melt flow direction of the resin when the resin layer is molded. The carbon fibers may be either pitch-based or PAN-based ones classified from raw materials, but PAN-based carbon fibers having a high elastic modulus are more preferable. The calcining temperature is not particularly limited, but a carbonized material calcined at about 1000 to 1500 ° C. is higher than that calcined at a high temperature of 2000 ° C. or higher to be converted into graphite. Even under PV, it is preferable because the screw shaft is not easily damaged by wear.

The average fiber diameter of the carbon fiber is 20 μm or less, preferably 5 to 15 μm. A thick carbon fiber exceeding this range is not preferable because extreme pressure is generated, and the effect of improving load resistance is poor, and in the case of a steel material whose screw shaft is not quenched, wear damage increases. The carbon fiber may be a chopped fiber or a milled fiber, but a milled fiber having a fiber length of less than 1 mm is preferable in order to obtain stable thin-wall formability.

Commercially available carbon fibers that can be used in the present invention include pitch-based carbon fibers manufactured by Kureha Co., Ltd .: Kureka M-101S, M-107S, M-101F, M-201S, M-207S, M-2007S, C- 103S, C-106S, C-203S and the like. Further, as a similar PAN-based carbon fiber, manufactured by Toho Tenax Co., Ltd .: Besfight HTA-CMF0160-0H, HTA-CMF0040-0H, HTA-C6, HTA-C6-S, or Toray Industries, Inc .: Torayca MLD-30 , MLD-300, T008, T010, and the like.

The resin composition forming the resin layer preferably uses the PEK-based resin as a base resin, and contains the carbon fiber and a PTFE resin that is a solid lubricant as essential components.

As the PTFE resin, any of molding powder by suspension polymerization method, fine powder by emulsion polymerization method, and recycled PTFE may be adopted. In order to stabilize the fluidity of a resin composition having a PEK-based resin as a base resin, it is preferable to employ recycled PTFE that is difficult to be fiberized by shearing at the time of molding and hardly increases the melt viscosity.

Regenerated PTFE is a heat-treated (heat history added) powder, a powder irradiated with γ rays or electron beams. For example, a powder obtained by heat-treating molding powder or fine powder, a powder obtained by further irradiating this powder with γ-rays or an electron beam, a powder obtained by pulverizing a molding powder or a molded product of fine powder, and then a γ-ray or electron beam. There are types such as irradiated powder, molding powder or fine powder irradiated with gamma rays or electron beams. Among the regenerated PTFE, it does not aggregate, does not fiberize at the melting temperature of the PEK resin, has an internal lubricating effect, and stably improves the fluidity of the resin composition containing the PEK resin as a base resin. Therefore, it is more preferable to use PTFE resin irradiated with γ rays or electron beams.

Examples of commercially available PTFE resins that can be used in the present invention include Kitamura Co., Ltd .: KTL-610, KTL-450, KTL-350, KTL-8N, KTL-400H, Mitsui DuPont Fluorochemical Co., Ltd .: Teflon (registered trademark). 7-J, TLP-10, Asahi Glass Co., Ltd .: Fullon G163, L150J, L169J, L170J, L172J, L173J, Daikin Industries, Ltd .: Polyflon M-15, Lubron L-5, Hoechst: Hostaflon TF9205, TF9207, etc. Can be mentioned. Further, PTFE modified with a side chain group having a perfluoroalkyl ether group, a fluoroalkyl group, or other fluoroalkyl may be used. Among the PTFE irradiated with γ rays or electron beams among the above, Kitamura Co., Ltd .: KTL-610, KTL-450, KTL-350, KTL-8N, KTL-8F, Asahi Glass Co., Ltd .: Fullon L169J, L170J, L172J, L173J, etc. are mentioned.

In addition, you may mix | blend a well-known resin additive with respect to a resin composition to such an extent that the effect of this invention is not inhibited. Examples of the additive include friction property improvers such as boron nitride, colorants such as carbon powder, iron oxide, and titanium oxide, and thermal conductivity improvers such as graphite and metal oxide powder.

The resin composition forming the resin layer preferably contains 5 to 30% by volume of carbon fiber and 1 to 30% by volume of PTFE resin as essential components when a PEK resin is used as a base resin. The balance excluding this essential component and other additives is PEK-based resin. The carbon fiber is more preferably 5 to 20% by volume, and the PTFE resin is more preferably 2 to 25% by volume.

When the blending ratio of the carbon fiber exceeds 30% by volume, the melt fluidity is remarkably lowered, it becomes difficult to form a thin wall, and there is a risk of wear damage when the screw shaft is a steel material without quenching. Moreover, when the blending ratio of the carbon fiber is less than 5% by volume, the effect of reinforcing the resin layer is poor, and sufficient creep resistance and wear resistance may not be obtained.

When the blending ratio of PTFE resin exceeds 30% by volume, the wear resistance and creep resistance may be lowered from the required levels. In addition, when the blending ratio of the PTFE resin is less than 1% by volume, the effect of imparting the required lubricity to the composition is poor, and sufficient sliding characteristics may not be obtained.

The means for mixing and kneading the above raw materials is not particularly limited, and only the powder raw material is dry-mixed with a Henschel mixer, ball mixer, ribbon blender, ladyge mixer, ultra Henschel mixer, etc. Melting and kneading can be performed with a melt extruder such as an extruder to obtain molding pellets (granules). In addition, a side feed may be used for charging the filler when melt kneading with a twin screw extruder or the like. Moreover, you may employ | adopt treatments, such as an annealing process, for physical property improvement. In the sliding nut of the present invention, the resin layer is preferably injection-molded by insert molding on the nut body using the molding pellets. As this specific method, for example, the manufacturing method described in Patent Document 4 can be used.

In order to obtain a sufficient adhesion strength against the friction force in use, the shear adhesion strength between the sintered metal of the nut body and the resin layer is 2 MPa or more (at a surface pressure of 10 MPa and a friction coefficient of 0.1). The safety factor is preferably 2 times or more. Furthermore, in order to raise a safety factor, 3 Mpa or more is preferable. In addition, in order to further increase the shear adhesion strength between the sintered metal of the nut body and the resin layer, the sintered metal surface on which the resin layer is formed may be provided with physical stoppers such as irregularities and grooves, and rotation prevention. Good.

The sliding nut and the sliding screw device of the present invention have been described above, but the embodiment of the present invention is not limited to this.

Now, the sliding bearing and compressor for a compressor according to the present invention will be described.

As a first embodiment of a compressor using a sliding bearing for a compressor of the present invention, an example of a single-headed piston compressor constituting a vehicle air conditioner will be described with reference to FIG.

As shown in FIG. 3, the compressor 5 includes a cylinder block 6, a front housing 7, and a rear housing 9 that constitute the housing. The rear housing 9 is joined and fixed to the cylinder block 6 via the valve forming body 8. Here, the crank chamber 10 is located in a portion surrounded by the cylinder block 6 and the front housing 7. A drive shaft 11 is rotatably supported by the housing so as to penetrate the crank chamber 10. The drive shaft 11 is made of metal or the like. One end side (left side in the figure) of the drive shaft 11 is directly connected to the vehicle engine via a power transmission mechanism. An iron lug plate 12 is fixed to the drive shaft 11 in the crank chamber 10 so as to be integrally rotatable. The drive shaft 11 and the lug plate 12 constitute a rotating member.

One end of the drive shaft 11 is rotatably supported by a radial sliding bearing 1a fitted in a through hole 7a provided in the front housing 7. The other end of the drive shaft 11 is rotatably supported by a radial slide bearing 1 b fitted in a through hole 6 a provided in the cylinder block 6. The radial sliding bearings 1a and 1b are the sliding bearings for the compressor of the present invention.

The swash plate 13 as a cam plate is accommodated in the crank chamber 10. The swash plate 13 can be rotated synchronously with the lug plate 12 and the drive shaft 11 by the operation connection with the lug plate 12 via the hinge mechanism 14 and the support of the drive shaft 11, and in the direction of the rotation center axis of the drive shaft 11. It is configured to be tiltable with respect to the drive shaft 11 while being accompanied by the sliding movement. A plurality of cylinder bores 15 are formed in the cylinder block 6, and a single-headed piston 16 is accommodated in the cylinder bore 15 so as to be capable of reciprocating. The front and rear openings of the cylinder bore 15 are closed by the valve forming body 8 and the piston 16, and a compression chamber whose volume changes according to the reciprocation of the piston 16 is formed in the cylinder bore 15. Each piston 16 is anchored to the outer peripheral portion of the swash plate 13 via a shoe 17. With this configuration, the rotational motion of the swash plate 13 accompanying the rotation of the drive shaft 11 is converted into the reciprocating linear motion of the piston 16 via the shoe 17. The piston 16, the shoe 17, the swash plate 13, the hinge mechanism 14 and the lug plate 12 constitute a crank mechanism, and the crank mechanism, the cylinder block 6 and the drive shaft 11 constitute a compression mechanism.

A thrust rolling bearing 18 a is disposed between the lug plate 12 and the front housing 7. The thrust rolling bearing 18 a is disposed on the side that supports the rotating member (the drive shaft 11 and the lug plate 12) in the thrust direction and receives the compression reaction force generated in the compression mechanism via the lug plate 12. The drive shaft 11 is supported at its rear end portion by a thrust rolling bearing 18b disposed in the through hole 6a of the cylinder block 6, so that the thrust movement to the rear is restricted.

In the rear housing 9, a suction chamber 19 and a discharge chamber 20 are formed. The refrigerant gas in the suction chamber 19 is introduced into the cylinder bore 15 through the valve forming body 8 by the movement of each piston 16. The low-pressure refrigerant gas introduced into the cylinder bore 15 is compressed to a predetermined pressure by the movement of the piston 16 and is introduced into the discharge chamber 20 via the valve forming body 8. The suction chamber 19, the discharge chamber 20, the cylinder bore 15, and the valve forming body 8 constitute a refrigerant path.

In the compressor 5 having the above configuration, when power is supplied from the vehicle engine to the drive shaft 11 via the power transmission mechanism, the swash plate 13 rotates together with the drive shaft 11. As the swash plate 13 rotates, each piston 16 is reciprocated at a stroke corresponding to the inclination angle of the swash plate 13, and refrigerant suction, compression, and discharge are sequentially repeated in each cylinder bore 15.

Hereinafter, based on FIG. 4, the radial plain bearing 1 (1a and 1b) which is a slide bearing for compressors of this invention is demonstrated in detail. FIG. 4 is a perspective view and a sectional view of a radial plain bearing which is a slide bearing for a compressor according to the present invention. The radial plain bearing 1 is a multi-layered plain bearing comprising a cylindrical sintered metal base 2 and a resin layer 3 provided on the inner peripheral surface thereof. The resin layer 3 is made of a resin composition having a PEK-based resin as a base resin, and is integrally provided by injection molding on the inner peripheral surface of the sintered metal base 2 with a thickness of 0.1 to 0.7 mm. It is formed by being. The inner peripheral surface of the resin layer 3 is a sliding surface that supports the drive shaft 11 (see FIG. 3).

The outer diameter shape of the radial plain bearing 1 is set to a shape along the through holes 6a and 7a (see FIG. 3) in the compressor. The outer peripheral surface of the radial plain bearing 1 and the inner peripheral surfaces of the through holes 6a and 7a (see FIG. 3) are set to be in close contact with each other as much as possible. In addition, the inner diameter shape is a shape along the drive shaft 11 (see FIG. 3) so that the clearance with the peripheral surface of the drive shaft is the minimum necessary for rotation support in a state where the drive shaft 11 is supported. Is set to

Conventional radial plain bearings perform machining such as cutting or grinding on the inner peripheral surface to finish the inner diameter of the sliding surface, improve roundness, and expose the bronze sintered layer. However, since the sliding bearing for a compressor of the present invention finishes the sliding surface (resin layer) by injection molding, it is not necessary to perform machining such as cutting or grinding. Further, unlike the conventional multi-layer bearing, it is not necessary to process the cutting part or bend with a lathe or a grinding machine after forming and cutting the multi-layer. As a result, the sliding surface has high dimensional accuracy while being easy to manufacture and low cost.

Since the radial sliding bearing 1 uses the sintered metal base material 2 as a bearing base material, the PEK-based resin molten resin penetrates deeply into the irregularities on the surface of the sintered metal base material 2 at the time of injection molding. The resin layer 3 can be firmly adhered to the substrate 2. In the injection molding, since the molten resin is poured at a high speed, the resin is likely to enter the unevenness (holes) of the porous sintered layer by shearing force while using the PEK resin as the base resin. Therefore, sufficient adhesion strength between the sintered metal substrate 2 and the resin layer 3 can be secured.

By using a resin composition based on PEK-based resin for the resin layer, the continuous use temperature is 250 ° C, and it has excellent heat resistance, oil / chemical resistance, creep resistance, and friction and wear characteristics. It becomes a sliding bearing. In addition, PEK-based resins have high toughness and mechanical properties at high temperatures, and are excellent in fatigue resistance and impact resistance. Therefore, even when frictional force, impact, vibration, etc. are applied during use, the resin layer is baked. It is difficult to peel off from the metal base. In the conventional radial sliding bearing, since the resin composition mainly composed of PTFE resin was a sliding surface, it was not possible to prevent the resin composition from peeling from the porous sintered layer at the time of abnormality. .

Specific examples of the PEK resin that can be used in the sliding bearing for the compressor include the same ones as those used in the above-described sliding nut.

The thickness of the resin layer is set to 0.1 to 0.7 mm. The thickness of the resin layer is the thickness of the surface portion that does not enter the sintered metal base material. In the case of a radial slide bearing, it is the thickness in the radial direction, and in the case of a thrust slide bearing, the thickness in the axial direction. That's it. This thickness range is set in consideration of the insert molding surface and physical properties. When the thickness of the resin layer is less than 0.1 mm, insert molding is difficult. In addition, durability during long-term use, that is, life may be shortened. On the other hand, if the thickness of the resin layer exceeds 0.7 mm, sink marks may occur and dimensional accuracy may be reduced. In addition, heat due to friction is difficult to escape from the friction surface to the sintered metal substrate, and the friction surface temperature increases. Further, the amount of deformation due to the load increases, the true contact area on the friction surface also increases, the frictional force and the frictional heat generation increase, and the seizure resistance may decrease. In consideration of heat radiation of the frictional heat to the sintered metal substrate, the thickness of the resin layer is preferably 0.2 to 0.5 mm.

The thickness of the resin layer is preferably 1/8 to 1/2 of the thickness of the sintered metal substrate. When the thickness of the resin layer is less than 1/8 of the thickness of the sintered metal base material, the resin layer becomes too thin relative to the base material, which may deteriorate durability during long-term use. On the other hand, if the thickness of the resin layer exceeds ½ of the thickness of the sintered metal base material, the resin layer becomes too thick relative to the base material, and heat from friction is generated from the friction surface to the sintered metal. It is difficult to escape to the base material and the friction surface temperature becomes high. Further, the amount of deformation due to the load increases, the true contact area on the friction surface also increases, the frictional force and the frictional heat generation increase, and the seizure resistance may decrease.

Examples of the material of the sintered metal substrate include iron, copper iron, copper, and stainless steel. Since the adhesion between the sintered metal substrate and the resin layer is excellent, it is preferable to employ a sintered metal whose main component is iron (which may include copper). Moreover, higher bearing strength can be obtained by employing a sintered metal mainly composed of iron. In addition, since copper is inferior to adhesiveness (adhesiveness) with resin rather than iron, when copper is included, the content of copper is preferably 10% by weight or less. More preferably, the copper content is 5% by weight or less.

As in the case of using the above-mentioned sliding nut, it is preferable to use a sintered metal not impregnated with oil for the sintered metal base material before forming the resin layer. Moreover, when using oil in the process of shaping | molding or re-pressing (sizing) of a sintered metal, it is preferable to set it as the non-oil-containing sintered metal which removed oil by solvent washing etc. Moreover, it is preferable to perform a steam process to the sintered metal base material before forming a resin layer.

The theoretical density ratio of the sintered metal substrate is preferably 0.7 to 0.9, as in the case of using the sliding nut described above. More preferably, the theoretical density ratio of the materials is 0.72 to 0.84. By setting the theoretical density ratio of the sintered metal base material to 0.7 to 0.9, the required density for securing the bearing strength of the sintered metal base material is obtained and the resin layer is sintered. Unevenness on the surface for firmly adhering to the base material made of sintered metal can be secured. It is also possible to hold the lubricating oil on the sintered metal substrate. Furthermore, the thermal conductivity of the sintered metal substrate can be ensured.

The resin composition forming the resin layer uses the PEK-based resin as a base resin, and a fiber filler such as glass fiber, carbon fiber, aramid fiber, or whisker can be blended in a dispersed state. Thereby, the mechanical strength of the resin layer can be further improved. In particular, in the sliding bearing for a compressor of the present invention, since the resin layer is thin with a thickness of 0.1 to 0.7 mm, it is desirable to improve the mechanical strength.

In addition to the fibrous filler, a solid lubricant such as PTFE resin, graphite and molybdenum disulfide, and an inorganic filler such as calcium carbonate, calcium sulfate, mica and talc can be blended. By blending the above-mentioned solid lubricant, it is possible to improve the seizure resistance by reducing friction even under non-lubricated conditions and even when the lubricating oil is dilute. Moreover, creep resistance can be improved by mix | blending the said inorganic filler.

Fibrous fillers, inorganic solid lubricants (graphite, molybdenum disulfide, etc.) and inorganic fillers have the effect of reducing the molding shrinkage of the PEK resin. Therefore, there is also an effect of suppressing the internal stress of the resin layer at the time of insert molding with the sintered metal base material.

FIG. 5 shows a radial sliding bearing having a resin layer made of a resin composition containing a fibrous filler. FIG. 5 is a perspective view and a cross-sectional view of a radial plain bearing (combination of fibrous filler in a resin layer) which is a slide bearing for a compressor according to the present invention. The radial plain bearing 1 has the same configuration as that of FIG. 4 except that the fibrous filler 4 is blended in the resin layer 3.

In forming the resin layer 3 by injection molding, by adjusting the melt flow direction of the resin composition, the fibrous filler 4 (in its length direction) is moved in the sliding direction of the slide bearing 1 (arrow in the figure). On the other hand, it is preferable to orient at an intersection angle as close to a right angle as possible at 45 degrees or more. In order to improve the mechanical strength of the resin layer, it is preferable to add a fibrous filler. However, since the end of the fiber of the fibrous filler is an edge, the end of the fiber is A certain drive shaft 11 (see FIG. 3) is easily physically damaged by wear, and the friction coefficient is difficult to stabilize. By orienting the fibrous filler (in the length direction) so as to intersect at 45 to 90 degrees with respect to the sliding direction of the sliding bearing, the edges at both ends of the fiber are 45 to 90 with respect to the sliding direction. Suitable for degrees. As a result, it is possible to reduce wear damage on the drive shaft due to the edges at both ends of the fiber and to stabilize the friction coefficient. It should be noted that the orientation of the fibrous filler is preferably closer to 90 degrees because there is less abrasion damage due to the fiber edge and the friction coefficient is stabilized. 80 to 90 degrees is particularly preferable.

The average fiber length of the fibrous filler is preferably 0.02 to 0.2 mm. If the thickness is less than 0.02 mm, a sufficient reinforcing effect cannot be obtained, and creep resistance and wear resistance may not be satisfied. When the thickness exceeds 0.2 mm, the ratio of the fiber length to the layer thickness of the resin layer becomes large, so that the thin formability is inferior. In particular, when insert molding is performed with a resin thickness of about 0.2 to 0.7 mm, if the fiber length exceeds 0.2 mm, thin-wall moldability is hindered. An average fiber length of 0.02 to 0.1 mm is desirable for further improving the stability of thin-wall molding.

Among the fibrous fillers, it is preferable to use carbon fibers. By using carbon fibers, the reinforcing effect, abrasion resistance, and low friction properties of the resin layer are particularly excellent. Carbon fiber has a strong orientation in the melt flow direction of the resin when the resin layer is molded. In particular, a carbon fiber having a small diameter and a relatively short length is selected. In this case, both edges of the carbon fiber are along the sliding direction of the sliding bearing for the compressor. For example, the orientation direction is 0 to less than 45 degrees. If it exists, the drive shaft which is a counterpart material may be damaged. Therefore, when thin and short carbon fibers are used, when the resin is injection-molded, the flow direction of the molten resin is set to be perpendicular or close to the sliding direction of the sliding bearing for the compressor, and the length of the fiber Orienting the direction to be 45 to 90 degrees with respect to the sliding direction of the sliding bearing for the compressor is extremely advantageous in order to stabilize the durability and the bearing torque low.

The carbon fiber used in the sliding bearing for the compressor may be either a pitch type or a PAN type classified from raw materials, but a PAN type carbon fiber having a high elastic modulus is preferable. The calcining temperature is not particularly limited, but a carbonized product calcined at about 1000 to 1500 ° C. is higher than that calcined at a high temperature of 2000 ° C. or higher to be converted into graphite. Even under PV, the drive shaft is less susceptible to wear damage, which is preferable. By adopting PAN-based carbon fiber among the carbon fibers, the elastic modulus of the resin layer is increased, and deformation and wear of the resin layer are reduced. Furthermore, the true contact area of the friction surface is reduced, and frictional heat generation is also reduced.

The average fiber diameter of the carbon fiber is 20 μm or less, preferably 5 to 15 μm. Thick carbon fiber exceeding this range generates extreme pressure, so the effect of improving load resistance is poor, and when the drive shaft is an aluminum alloy or non-quenched steel material, wear damage of the drive shaft increases, which is not preferable. . The carbon fiber may be a chopped fiber or a milled fiber, but a milled fiber having a fiber length of less than 1 mm is preferable in order to obtain stable thin-wall formability.

As a commercial product of carbon fiber that can be used in the sliding bearing for the compressor, the same one as that used in the above-described sliding nut can be cited.

As the PTFE resin that can be used in the sliding bearing for the compressor and its commercial product, the same ones as those used in the above-described sliding nut can be cited.

The resin composition forming the resin layer preferably contains PEK-based resin as a base resin, 5 to 30% by volume of carbon fiber, and 1 to 30% by volume of PTFE resin as essential components. The balance excluding this essential component and other additives is PEK-based resin. By using this blending ratio, even under high PV conditions, the deformation and wear of the resin layer, the aggressiveness to the surface of the drive shaft which is the counterpart material are small, and the resistance to oil and the like is also high. Further, the carbon fiber is more preferably 5 to 20% by volume, and the PTFE resin is more preferably 2 to 25% by volume.

If the blending ratio of carbon fiber exceeds 30% by volume, the melt fluidity will be significantly reduced, making it difficult to form a thin wall, and if the drive shaft that is the counterpart material is an aluminum alloy or non-quenched steel, there is a risk of wear damage. There is. Moreover, when the blending ratio of the carbon fiber is less than 5% by volume, the effect of reinforcing the resin layer is poor, and sufficient creep resistance and wear resistance may not be obtained.

The means for mixing and kneading the above raw materials is not particularly limited, and only the powder raw material is dry-mixed with a Henschel mixer, ball mixer, ribbon blender, ladyge mixer, ultra Henschel mixer, etc. Melting and kneading can be performed with a melt extruder such as an extruder to obtain molding pellets (granules). In addition, a side feed may be used for charging the filler when melt kneading with a twin screw extruder or the like. Using this molding pellet, a resin layer is injection-molded by insert molding on a sintered metal substrate. By adopting injection molding, it is excellent in precision moldability and manufacturing efficiency. Moreover, you may employ | adopt treatments, such as an annealing process, for physical property improvement.

The resin composition forming the resin layer preferably has a melt viscosity of 50 to 200 Pa · s at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ . When the melt viscosity is within this range, it becomes possible to precisely form and align the fibrous filler at a predetermined angle, and a thin insert molding of 0.1 to 0.7 mm is formed on the surface of the sintered metal substrate. It can be done smoothly. If the melt viscosity is less than the predetermined range or exceeds the predetermined range, it is not easy to reliably obtain a precise moldability and to orient the fibrous filler at a predetermined angle. By making thin insert molding possible and making post-processing after insert molding unnecessary, manufacturing becomes easy and manufacturing costs can be reduced.

In order to achieve a melt viscosity of 50 to 200 Pa · s at a resin temperature of 380 ° C. and a shear rate of 1000 s ^−1, it is particularly preferable to employ a PEK resin having a melt viscosity of 130 Pa · s or less under these conditions. An example of such a PEK-based resin is manufactured by Victrex: PEEK (90P, 90G).

In order to obtain a sufficient adhesion strength against the friction force in use, the shear adhesion strength between the sintered metal substrate and the resin layer is 2 MPa or more (at a surface pressure of 10 MPa and a friction coefficient of 0.1). The safety factor is preferably 2 times or more. Furthermore, in order to raise a safety factor, 3 Mpa or more is preferable. In order to further increase the shear adhesion strength between the sintered metal substrate and the resin layer, the sintered metal surface on which the resin layer is formed may be provided with physical stoppers such as irregularities and grooves, and rotation prevention. Good.

In the first embodiment shown in FIG. 3, the drive shaft 11 is formed by sliding the resin layers of the radial bearings 1a and 1b having excellent heat resistance, low friction, wear resistance, load resistance, creep resistance, and the like. It is supported in sliding contact with the moving surface (inner peripheral surface). For this reason, wear on the sliding contact surface and deformation of the resin layer can be prevented, and low rotational torque can be stably obtained.

In addition, a lip seal 7b is provided in a portion of the through hole 7a in front of the radial sliding bearing 1a (left side in the figure) to prevent the refrigerant gas in the housing from leaking outside through the through hole 7a. is doing. Here, the radial plain bearing 1a is excellent in dimensional accuracy, and is set in a shape along this so that the clearance with the peripheral surface of the drive shaft 11 is the minimum necessary for rotation support, and The outer peripheral surface of the radial sliding bearing 1a and the inner peripheral surface of the through hole 7a are set so as to be in close contact with each other as much as possible. For this reason, it becomes easy to maintain the pressure of the space between the radial sliding bearing 1a and the lip seal 7b in the through hole 7a lower than the pressure of the crank chamber 10. With this configuration, the burden on the lip seal 7b for preventing leakage of refrigerant gas in the housing to the outside through the through hole 7a is reduced.

Furthermore, in the first embodiment, the radial plain bearings 1a and 1b are disposed in the crank chamber 10 that is not included in the refrigerant path in the housing. According to these radial sliding bearings 1a and 1b, even in the crank chamber 10 where the circulation amount of the refrigerant gas is relatively small and the lubricating effect by the mist-like lubricating oil mixed in the refrigerant gas is low, the radial sliding is caused by the sliding surface of the resin layer. Wear of the sliding contact portion between the slide bearings 1a and 1b and the drive shaft 11 can be suppressed. As a result, the life of the compressor can be extended. Therefore, it is particularly useful to employ the radial plain bearings 1a and 1b in the compressor of this embodiment.

A second embodiment of a compressor using a sliding bearing for a compressor according to the present invention will be described with reference to FIG. In the second embodiment, the configuration of the compressor in the first embodiment shown in FIG. 3 is replaced with a thrust rolling bearing 18a, and a thrust sliding bearing 21 that is a sliding bearing for a compressor according to the present invention is used. It has been changed to. Other configurations are the same as those of the first embodiment.

As shown in FIG. 6, a thrust sliding bearing 21 is disposed between the front housing 7 and the lug plate 12. The thrust slide bearing 21 is fixed to the lug plate 12 and is in sliding contact with an iron ring-shaped plate 24 fixed to the front housing 7. By the sliding contact between the thrust sliding bearing and the plate 24, the thrust movement of the rotating member forward (left side in the figure) is restricted.

The thrust slide bearing 21 will be described with reference to FIG. FIG. 7 is a perspective view and a sectional view of a thrust sliding bearing which is a sliding bearing for a compressor according to the present invention. The thrust sliding bearing 21 is a multi-layered sliding composed of a ring-shaped sintered metal base material 22 and a resin layer 23 provided on a surface facing the plate 24 (see FIG. 6) of the base material. It is a bearing. The resin layer 23 is made of a resin composition having a PEK-based resin as a base resin, and is provided integrally with the surface of the sintered metal base 22 by injection molding so as to have a thickness of 0.1 to 0.7 mm. It is formed by that. The surface of the resin layer 23 (the side opposite to the base material) is a sliding surface that is in sliding contact with the plate 24 (see FIG. 6). The sintered metal substrate, the resin composition, the method for forming the resin layer, and the like are the same as in the case of the first embodiment.

In the second embodiment, the thrust sliding bearing 21 is employed as a bearing that supports the rotating member on the side that receives the compression reaction force generated in the compression mechanism through the lug plate 12 in the thrust direction. In this embodiment, the cost can be reduced as compared with the case where a rolling bearing is employed. Further, this thrust slide bearing is provided in the crank chamber 10 having a low lubrication effect that is not included in the refrigerant path, as in the case of the radial slide bearing of the first embodiment. Wear of the sliding contact portion between the bearing 21 and the plate 24 can be suppressed. As a result, the life of the compressor can be extended. Therefore, it is particularly useful to employ the thrust slide bearing 21 in the compressor of this embodiment.

In this embodiment, a thrust sliding bearing which is a sliding bearing for a compressor according to the present invention may be employed in place of the thrust rolling bearing 18b.

As a third embodiment of a compressor using a sliding bearing for a compressor of the present invention, an example of a double-headed piston compressor constituting a vehicle air conditioner will be described with reference to FIG. In the compressor 5 ′ of this aspect, a housing is constituted by a pair of cylinder blocks 33, a front housing 34, and a rear housing 35. Further, the drive shaft 32 and the swash plate 36 fixed to the drive shaft 32 in the crank chamber 37 constitute a rotating member. The plurality of cylinder bores 33a are formed at predetermined intervals on the same circumference between both ends of each cylinder block 33 so as to extend in parallel with the drive shaft 32. The double-headed piston 39 is inserted into and supported by each cylinder bore 33a so as to reciprocate, and a compression chamber is formed between the both end faces and the corresponding valve forming bodies 40. The shoe 38 and the swash plate 36 constitute a crank mechanism, and the crank mechanism, the cylinder block 33 (cylinder bore 33a), the piston 39, and the drive shaft 32 constitute a compression mechanism.

The drive shaft 32 is rotatably supported at the center of the cylinder block 33 and the front housing 34 via a pair of radial slide bearings 31a and 31b, and operates on an external drive source such as a vehicle engine via a power transmission mechanism. It is connected. The radial slide bearings 31 a and 31 b are inserted into a receiving hole 33 b formed in the center of the cylinder block 33 so as to communicate with a crank chamber 37 formed inside the cylinder block 33. The radial sliding bearings 31a and 31b are the sliding bearings for the compressor of the present invention. The specific configuration is the same as that of the first embodiment except for the dimensions in the radial direction and the axial direction, and is manufactured by the same manufacturing method.

Further, the pair of thrust rolling bearings 44 is provided between the front and rear end surfaces of the support cylindrical portion of the swash plate 36 and the central portion of each cylinder block 33 facing each other, and through the thrust rolling bearing 44. A swash plate 36 is held in a state of being sandwiched between the cylinder blocks 33.

The insertion hole 34a of the drive shaft and the accommodation hole 33b formed in the cylinder block 33 are in communication with each other via a through-hole formed in the valve forming body 40 (left side in the figure). A lip seal 34b is provided in the insertion hole 34a to prevent leakage of refrigerant gas in the housing to the outside through the insertion hole 34a. Here, the radial plain bearing 31a is set to a shape along this so that the dimensional accuracy is excellent, and the clearance with the peripheral surface of the drive shaft 32 becomes the minimum necessary for rotation support, and The outer peripheral surface of the radial sliding bearing 31a and the inner peripheral surface of the accommodation hole 33b are set so as to be in close contact with each other as much as possible. For this reason, it is easy to maintain the pressure in the space between the lip seal 34b and the radial sliding bearing 31a in the insertion hole 34a lower than the pressure in the crank chamber 37. With this configuration, the burden on the lip seal 34b for preventing leakage of refrigerant gas in the housing through the insertion hole 34a to the outside is reduced.

In this embodiment, the crank chamber 37, the bolt insertion hole 43, the suction chamber 41, the compression chamber, the discharge chamber 42, and the like constitute a refrigerant path in the housing. Each part in the refrigerant path in the housing is lubricated by mist-like lubricating oil or the like mixed in the refrigerant gas flowing through the path. For this reason, the sliding contact portion between the radial slide bearings 31a and 31b and the drive shaft 32 disposed in the crank chamber 37 (specifically, the accommodation hole 33b) constituting the refrigerant path has a solid resin layer of the slide bearing. In addition to the lubricating action, the lubricating action by the lubricating oil works greatly. Thereby, the sliding contact portion between the drive shaft 32 and the sliding bearings 31a and 31b is well lubricated, and the life of the compressor can be extended.

In this embodiment, a thrust sliding bearing which is a sliding bearing for a compressor according to the present invention may be employed in place of the thrust rolling bearing 44.

Referring to FIG. 9, an example of a scroll type compressor constituting a vehicle air conditioner will be described as a fourth embodiment of a compressor using the compressor sliding bearing of the present invention. In the compressor 5 ″ in this aspect, the fixed scroll 51, the center housing 52, and the motor housing 53 constitute a housing. The center housing 52 and the motor housing 53 support a shaft 54 made of iron as a rotating shaft so as to be rotatable via

radial sliding bearings

55 and 56. Further, an eccentric shaft 54a is formed integrally with the shaft 54, and a balance weight 57 is supported on the shaft 54a. The shaft 54 and the balance weight 57 constitute a rotating member.

The eccentric shaft 54a is supported through a radial sliding bearing 59 and a bush 60 so as to be relatively rotatable so that the movable scroll 58 faces the fixed scroll 51. The radial plain bearing 59 is fitted and accommodated in a substantially cylindrical bush 60 fitted in a boss portion 58c projecting from the movable substrate 58a. The inner peripheral surface of the radial sliding bearing 59 becomes a sliding contact surface with the outer peripheral surface of the eccentric shaft 54a. A movable spiral wall 58b is formed on the movable substrate 58a of the movable scroll 58, and a fixed spiral wall 51b that meshes with the movable spiral wall 58b is formed on the fixed substrate 51a of the fixed scroll 51. A region defined by the fixed substrate 51 a, the fixed spiral wall 51 b, the movable substrate 58 a, and the movable spiral wall 58 b becomes the sealed chamber 61 whose volume decreases as the movable scroll 58 rotates. The fixed scroll 51, the movable scroll 58, the center housing 52, the bush 60, the

radial sliding bearings

55 and 59, the shaft 54, the balance weight 57, and the like constitute a scroll type compression mechanism.

A stator 62 as a stator is fixed to the inner peripheral surface of the motor housing 53, and a rotor 63 as a rotor is fixed to the outer peripheral surface of the shaft 54 at a position facing the stator 62. The stator 62 and the rotor 63 constitute an electric motor, and the rotor 63 and the shaft 54 are integrally rotated by energizing the stator 62. The center housing 52 is provided with a partition wall portion 52a, and the radial sliding bearing 55 is fitted into a through hole 52b formed at the center of the partition wall portion 52a. The inner peripheral surface of the radial sliding bearing 55 is a sliding contact surface with the outer peripheral surface of the shaft 54.

The shaft 54 is formed therein with a fluid passage 54 b that communicates the discharge chamber 64 and the motor chamber 65, and a fluid passage 54 c that communicates the motor chamber 65 and the outside of the motor housing 53. As the movable scroll 58 revolves, the refrigerant gas that has flowed into the sealed chamber 61 from the inlet of the fixed scroll 51 passes through the discharge port 58d, the discharge chamber 64, the fluid passage 54b, the motor chamber 65, and the fluid passage 54c, and passes through the motor housing. It flows out to the outside through an outlet 53 a provided in the wall portion of 53. For this reason, the discharge chamber 64, the fluid passage 54b, the motor chamber 65, and the fluid passage 54c become a high pressure region having a pressure value substantially equal to the discharge pressure. On the other hand, the outer side of the ring-shaped seal member 66 is a low pressure chamber 67 having a pressure value close to the suction pressure.

Radial

plain bearings

55, 56, and 59 are the plain bearings for a compressor of the present invention. The specific configuration is the same as that of the first embodiment except for the dimensions in the radial direction and the axial direction, and is manufactured by the same manufacturing method.

The

radial sliding bearings

55 and 59 are inserted into the through hole 52b and the bush 60, respectively, and the clearance with the peripheral surface of the shaft 54 is maintained when the shaft 54 (the bearing 59 is specifically the eccentric shaft 54a) is inserted. The shape along this is set so as to be the minimum necessary for the rotation support. The outer peripheral surface of the radial sliding bearing 55 and the inner peripheral surface of the through hole 52b are in close contact with the outer peripheral surface of the radial sliding bearing 59 and the inner peripheral surface of the bush 60 as much as possible. Is set to

The communication between the space 68 surrounded by the outer peripheral side of the boss portion 58c and the inner peripheral side of the partition wall portion 52a and the motor chamber 65 through the clearance between the through hole 52b and the shaft 54 is substantially blocked by the radial slide bearing 55. Has been. Further, the communication between the discharge chamber 64 and the space 68 through the gap between the bush 60 and the eccentric shaft 54 a is substantially blocked by a radial sliding bearing 59. That is, the radial

plain bearings

55 and 59 are provided so as to pressure-isolate the internal space of the housing.

The space 68 is formed by adjusting the pressure of the regulating valve or leaking refrigerant gas from the high pressure region (the motor chamber 65 or the discharge chamber 64) through a slight gap between the

radial slide bearings

55 and 59 and the shaft 54. The intermediate pressure is maintained at a lower pressure than that of the low pressure chamber 67. By providing a region (space 68) whose pressure is lower than that of the high pressure region on the back surface of the movable scroll 58, a load applied to the movable scroll 58 due to the pressure applied to the back surface of the movable scroll 58 is reduced. Therefore, smooth revolution of the movable scroll 58 is obtained, and mechanical loss of the movable scroll 58 is reduced.

Since the

radial slide bearings

55 and 59 are excellent in wear resistance as described above, the wear of the sliding contact portion with the shaft 54 can be reduced, and the reduction of the pressure isolation effect due to the widening of the gap between the two due to this wear is suppressed. it can. As described above, the radial

plain bearings

55 and 59 can exhibit good sealing performance with the shaft 54, and it is easy to maintain the effect high. For this reason, the discharge chamber 64 and the space 68 can be effectively separated from the motor chamber 65 and the space 68 by pressure without providing a special seal member.

As described above, the first to fourth embodiments of the sliding bearing for compressor and the compressor of the present invention have been described, but the embodiment of the present invention is not limited to this.

Now, the cradle guide and the variable displacement axial piston pump of the variable displacement axial piston pump of the present invention will be described.

An embodiment of a variable displacement axial piston pump using the cradle guide of the present invention will be described with reference to FIG. FIG. 10 is a longitudinal sectional view of a variable displacement axial piston pump. As shown in FIG. 10, the cradle guide 81 of the variable displacement axial piston pump is in sliding contact with a cradle 83 that adjusts the stroke of the piston 82, and holds the cradle 83 so that it can swing. Here, the cradle guide 81 has a resin layer 81b made of a resin composition containing a PEK-based resin as a base resin on the surface side of the sintered metal member 81a, that is, the sliding surface with respect to the cradle 83. It is 7 mm thick and is provided integrally by injection molding. In addition, although the resin layer 81b is thin with the thickness of the said range, in FIG. 10, it has described thicker than actual for description.

In the variable displacement type axial piston pump of this embodiment, a rotary shaft 87 is rotatably supported between the end walls of a pair of joined

housings

85 and 86. A cylinder block 88 is supported on the rotating shaft 87 so as not to be relatively rotatable. A plurality of pistons 82 are accommodated in a cylinder block 88 that rotates integrally with the rotating shaft 87 so as to be slidable in the axial direction of the rotating shaft 87. The piston accommodating chamber 88 a in the cylinder block 88 is alternately connected to the arc-shaped suction port 89 a and the discharge port 89 b formed in the valve plate 89 in conjunction with the rotation of the rotating shaft 87. As a result, the hydraulic oil is sucked into the piston accommodating chambers 88a from the suction ports 89a, and the hydraulic oil in the piston accommodating chambers 88a in the cylinder block 88 rotated together with the rotating shaft 87 is discharged to the discharge port 89b.

The pressing spring 90 urges the cylinder block 88 toward the cradle 83 side. As a result, the shoe 92 made of an aluminum material held by the retainer 91 is in close contact with the flat portion of the cradle 83 around the rotation shaft 87. The piston 82 fitted to the shoe 92 is reciprocated at a stroke corresponding to the inclination angle of the cradle 83 as the rotating shaft 87 rotates. The tilt angle of the cradle 83 is always controlled to an appropriate angle by the pressing force of the pressing spring 93 in the housing 85 and the hydraulic pressure from the cylinder 95 adjusted by the hydraulic control device 94.

FIG. 11 is a perspective view of the cradle guide 81. As shown in FIGS. 10 and 11, two cradle guides 81 are fixed and provided in a housing 85 made of aluminum alloy. A rotating shaft 87 is disposed between the two cradle guides 81 so as to pass through the shaft hole of the cradle 83.

11, the cradle guide 81 has a main body composed of a sintered metal member 81a. In this main body, the support surface of the cradle 83 is formed in an arcuate shape, and a resin layer 81b having a predetermined composition is formed on the support surface with a thin wall and a constant thickness by injection molding. The arc surface on which the resin layer 81 b is formed becomes a sliding surface with respect to the cradle 83. By making the cradle guide body a sintered metal member, the number of parts is small, the structure is simple, and the manufacturing cost is low.

Other aspects of the cradle guide will be described based on FIG. 12 and FIG. 12 is a perspective view of another embodiment of the cradle guide 81, and FIG. 13 is an exploded perspective view of the cradle guide of FIG. As shown in FIG. 12, the cradle guide 81 includes a molten metal main body 81c, and a sintered metal member 81a in which a resin layer 81b is formed is installed on the main body 81c. The sintered metal member 81a is an arc-shaped (partially cylindrical) sintered bush formed with a resin layer 81b, and is set on a support surface of a cradle 83 formed in an arc surface shape in the main body 81c. . The surface on the main body 81c side of the sintered metal member 81a is formed in the same shape corresponding to the arc surface shape of the support surface of the main body 81c. The arc surface on which the resin layer 81 b of the sintered bush is formed becomes a sliding surface with respect to the cradle 83. Further, as shown in FIG. 13, the pair of recessed bushes 81f and the projecting portions 81g are fitted so that the pair of sintered bushes (81a + 81b) does not deviate from the support surfaces 81d, 81e of the cradle guide of the main body 81c. It is fixed with. In addition, the uneven | corrugated | grooved part for fixing a sintered bush may make the uneven | corrugated relationship reverse to what is shown in FIG. 13, and the shape can also be made into arbitrary shapes. Alternatively, it is most desirable in view of manufacturing costs to insert the pin into the recess 81f and fit the sintered bush by providing a pin hole.

The cradle 83 is formed of, for example, a silicon-containing aluminum alloy, and a pair of arcuate sliding

contact portions

83a and 83b corresponding to the support surfaces 81d and 81e of the cradle guides are provided on the back surface thereof. In the embodiment shown in FIGS. 12 and 13, both sliding

contact portions

83a and 83b are assembled so as to be in contact with the support surfaces 81d and 81e via a pair of sintered bushes (81a + 81b).

12 and 13, the material of the cradle guide main body 81 c is not particularly limited as long as it is a molten metal. For example, high carbon chromium bearing steel, chromium molybdenum steel, carbon steel for machine structure, stainless steel, cast iron, aluminum alloy, brass and the like can be used. By making the main body 81c made of molten metal, the mechanical strength of the entire cradle guide can be increased as compared with the case where the whole main body is made of a sintered metal member.

The resin layer 81b is made of a resin composition having a PEK-based resin as a base resin, and is integrally laminated by injection molding at a thickness of 0.1 to 0.7 mm on the surface of the sintered metal member 81a that is in sliding contact with the cradle. It is formed by being provided.

Since the resin layer 81b is formed on the surface of the sintered metal member 81a, the molten resin of the PEK resin penetrates deeply into the irregularities on the surface of the sintered metal member 81a at the time of injection molding, and the resin layer 81b is inserted into the member 81a. Can be firmly attached. In injection molding, since the molten resin is poured at a high speed and high pressure, the resin is likely to enter the irregularities (holes) of the porous sintered layer by shearing force while using the PEK resin as the base resin. Therefore, sufficient adhesion strength between the sintered metal member 81a and the resin layer 81b can be secured.

By using a resin composition based on PEK-based resin for the resin layer, the continuous use temperature is 250 ° C, and variable with excellent heat resistance, oil / chemical resistance, creep resistance, and friction and wear characteristics. Become a cradle guide for displacement axial piston pumps. In addition, PEK-based resins have high toughness and mechanical properties at high temperatures, and are excellent in fatigue resistance and impact resistance. Therefore, even when frictional force, impact, vibration, etc. are applied during use, the resin layer is baked. It is difficult to peel off from the metal member. In the cradle guide of the conventional variable capacity type axial piston pump, since the resin composition mainly composed of a fluororesin such as PTFE resin is a sliding surface, the resin composition peels off from the porous sintered layer at the time of abnormality. I couldn't prevent that.

Specific examples of the PEK-based resin that can be used in this cradle guide include the same as those used in the above-described sliding nut.

The thickness of the resin layer is set to 0.1 to 0.7 mm. The thickness of the resin layer is the thickness of the surface portion that does not enter the sintered metal member. This thickness range is set in consideration of the insert molding surface and physical properties. When the thickness of the resin layer is less than 0.1 mm, insert molding is difficult. In addition, durability during long-term use, that is, life may be shortened. On the other hand, if the thickness of the resin layer exceeds 0.7 mm, sink marks may occur and dimensional accuracy may be reduced. In addition, heat due to friction is difficult to escape from the friction surface to the sintered metal member, and the friction surface temperature increases. Further, the amount of deformation due to the load increases, the true contact area on the friction surface also increases, the frictional force and the frictional heat generation increase, and the seizure resistance may decrease. In consideration of heat dissipation of the frictional heat to the sintered metal member, the thickness of the resin layer is preferably 0.2 to 0.5 mm.

In the embodiment using a sintered bush as shown in FIG. 12, the thickness of the resin layer is preferably 1/8 to 1/2 of the thickness of the sintered metal member. If the thickness of the resin layer is less than 1/8 of the thickness of the sintered metal member, the resin layer becomes too thin relative to the sintered metal member, which may be inferior in durability during long-term use. . On the other hand, if the thickness of the resin layer exceeds ½ of the thickness of the sintered metal member, the resin layer becomes too thick relative to the sintered metal member, and heat due to friction is burned from the friction surface. It is difficult to escape to the metal member, and the friction surface temperature becomes high. Further, the amount of deformation due to the load increases, the true contact area on the friction surface also increases, the frictional force and the frictional heat generation increase, and the seizure resistance may decrease.

Examples of the material of the sintered metal member include iron, copper iron, copper, and stainless steel. Since the adhesion between the sintered metal member and the resin layer is excellent, it is preferable to employ a sintered metal whose main component is iron (which may include copper). In addition, higher mechanical strength can be obtained by employing a sintered metal mainly composed of iron. In addition, since copper is inferior to adhesiveness (adhesiveness) with resin rather than iron, when copper is included, the content of copper is preferably 10% by weight or less. More preferably, the copper content is 5% by weight or less.

As in the case of using the above-mentioned sliding nut, it is preferable to use a sintered metal not impregnated with oil for the sintered metal member before forming the resin layer. Moreover, when using oil in the process of shaping | molding or re-pressing (sizing) of a sintered metal, it is preferable to set it as the non-oil-containing sintered metal which removed oil by solvent washing etc. Moreover, it is preferable to perform a steam process to the sintered metal member before forming a resin layer.

The theoretical density ratio of the sintered metal member is preferably 0.7 to 0.9, as in the case of using the sliding nut described above. More preferably, the theoretical density ratio of the materials is 0.72 to 0.84. By setting the theoretical density ratio of the sintered metal member to 0.7 to 0.9, the strength of the cradle guide carried by the sintered metal member (especially when the entire body is composed of the sintered metal member) In addition to having the required denseness to ensure, it is possible to ensure surface irregularities for firmly attaching the resin layer to the sintered metal member. It is also possible to hold the lubricating oil on the sintered metal member. Furthermore, the thermal conductivity of the sintered metal member can be ensured.

The resin composition forming the resin layer uses a PEK-based resin as a base resin, and a fibrous filler such as glass fiber, carbon fiber, aramid fiber, or whisker can be blended in a dispersed state. Thereby, the mechanical strength of the resin layer can be further improved. In particular, in the cradle guide of the variable displacement type axial piston pump of the present invention, since the resin layer is thin with a thickness of 0.1 to 0.7 mm, it is desirable to improve the mechanical strength.

Fibrous fillers, inorganic solid lubricants (graphite, molybdenum disulfide, etc.) and inorganic fillers have the effect of reducing the molding shrinkage of the PEK resin. Therefore, there is also an effect of suppressing the internal stress of the resin layer at the time of insert molding with a sintered metal member.

FIG. 14 shows a cradle guide having a resin layer made of a resin composition containing a fibrous filler. FIG. 14 is a perspective view of a cradle guide (containing a fibrous filler in a resin layer). The cradle guide 81 has the same configuration as that of FIG. 11 except that the fibrous filler 84 is blended in the resin layer 81b.

When the resin layer 81b is formed by injection molding, the fibrous filler 84 (in its length direction) is adjusted with respect to the sliding direction of the cradle guide 81 (arrow in the figure) by adjusting the melt flow direction of the resin composition. It is preferable to align at an intersecting angle as close to a right angle as possible at 45 degrees or more. In order to improve the mechanical strength of the resin layer 81b, it is preferable to mix a fibrous filler. However, since the end of the fiber of the fibrous filler has an edge shape, the end of the fiber is used as a counterpart material. The cradle 83 is easily subject to physical wear damage and the friction coefficient is difficult to stabilize. By orienting the fibrous filler (in the length direction) so as to intersect at 45 to 90 degrees with respect to the sliding direction of the cradle guide, the edges at both ends of the fiber are 45 to 90 with respect to the sliding direction. Suitable for degrees. As a result, it is possible to reduce wear damage of the mating member due to the edges at both ends of the fiber and to stabilize the friction coefficient. It should be noted that the orientation of the fibrous filler is preferably closer to 90 degrees because there is less abrasion damage due to the fiber edge and the friction coefficient is stabilized. 80 to 90 degrees is particularly preferable.

The average fiber length of the fibrous filler is preferably 0.02 to 0.2 mm. If the thickness is less than 0.02 mm, a sufficient reinforcing effect cannot be obtained, and creep resistance and wear resistance may not be satisfied. When the thickness exceeds 0.2 mm, the ratio of the fiber length to the layer thickness of the resin layer becomes large, so that the thin formability is inferior. In particular, in the case of insert molding with a resin thickness of 0.2 to 0.7 mm, if the fiber length exceeds 0.2 mm, the thin-wall moldability is hindered. An average fiber length of 0.02 to 0.1 mm is desirable for further improving the stability of thin-wall molding.

Among the fibrous fillers, it is preferable to use carbon fibers. By using carbon fibers, the reinforcing effect, abrasion resistance, and low friction properties of the resin layer are particularly excellent. Carbon fiber has a strong orientation in the melt flow direction of the resin when the resin layer is molded. In particular, a carbon fiber having a small diameter and a relatively short length is selected. In this case, the edges of both ends of the carbon fiber are along the sliding direction of the cradle guide. For example, the orientation direction is 0 to less than 45 degrees. The opponent's cradle may be damaged. Therefore, when thin and short carbon fibers are used, when the resin is injection molded, the flow direction of the molten resin is set to a right angle or a near right angle with the sliding direction of the cradle guide, and the length direction of the fiber is set to the cradle. It is extremely advantageous to orient at 45 to 90 degrees with respect to the sliding direction of the guide in order to stabilize the durability and sliding torque low.

The carbon fiber used in this cradle guide may be either a pitch-based or PAN-based one classified from raw materials, but a PAN-based carbon fiber having a high elastic modulus is preferred. The calcining temperature is not particularly limited, but a carbonized material calcined at about 1000 to 1500 ° C. is higher than that calcined at a high temperature of 2000 ° C. or higher to be converted into graphite. Even under PV, it is preferable because the mating material is hardly damaged by wear.

The average fiber diameter of the carbon fiber is 20 μm or less, preferably 5 to 15 μm. Thick carbon fiber exceeding this range generates extreme pressure, so the effect of improving load resistance is poor, and when the cradle, which is the counterpart material, is an aluminum alloy or non-quenched steel material, the wear damage of the counterpart material increases. Therefore, it is not preferable. The carbon fiber may be a chopped fiber or a milled fiber, but a milled fiber having a fiber length of less than 1 mm is preferable in order to obtain stable thin-wall formability.

As the commercially available carbon fiber that can be used in this cradle guide, the same products as those used in the above-mentioned sliding nut can be mentioned.

The resin composition forming the resin layer preferably uses a PEK-based resin as a base resin and contains the carbon fiber and a PTFE resin as a solid lubricant as essential components.

As the PTFE resin that can be used in this cradle guide and its commercial products, the same ones as those used in the above-mentioned sliding nut can be mentioned.

The resin composition forming the resin layer preferably contains PEK-based resin as a base resin, 5 to 30% by volume of carbon fiber, and 1 to 30% by volume of PTFE resin as essential components. The balance excluding this essential component and other additives is PEK-based resin. By adopting this blending ratio, even under high PV conditions, the deformation and wear of the resin layer, the aggressiveness to the cradle surface as the counterpart material are small, and the resistance to oil and the like is also high. Further, the carbon fiber is more preferably 5 to 20% by volume, and the PTFE resin is more preferably 2 to 25% by volume.

If the mixing ratio of the carbon fiber exceeds 30% by volume, the melt fluidity is remarkably lowered, making it difficult to form a thin wall, and when the cradle as the counterpart material is an aluminum alloy or non-quenched steel, there is a risk of wear damage. is there. Moreover, when the blending ratio of the carbon fiber is less than 5% by volume, the effect of reinforcing the resin layer is poor, and sufficient creep resistance and wear resistance may not be obtained.

The means for mixing and kneading the above raw materials is not particularly limited, and only the powder raw material is dry-mixed with a Henschel mixer, ball mixer, ribbon blender, ladyge mixer, ultra Henschel mixer, etc. Melting and kneading can be performed with a melt extruder such as an extruder to obtain molding pellets (granules). In addition, a side feed may be used for charging the filler when melt kneading with a twin screw extruder or the like. Using this pellet for molding, a resin layer is injection-molded by insert molding on a sintered metal member. By adopting injection molding, it is excellent in precision moldability and manufacturing efficiency. Moreover, you may employ | adopt treatments, such as an annealing process, for physical property improvement.

The resin composition forming the resin layer has a melt viscosity of 50 to 200 Pa · s at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ , similar to the resin composition forming the resin layer of the sliding bearing for a compressor described above. Preferably there is.

In order to obtain sufficient adhesion strength against the friction force during use, the shear adhesion strength between the sintered metal member and the resin layer is preferably 2 MPa or more. Furthermore, in order to raise a safety factor, 3 Mpa or more is preferable. Further, in order to further increase the shear adhesion strength between the sintered metal member and the resin layer, physical peeling measures such as unevenness and grooves may be taken on the sintered metal surface on which the resin layer is formed.

For example, in order to prevent the resin layer 81b from being peeled off from the sintered metal member 81a during sliding with the cradle, as shown in FIG. 15, irregularities can be provided on the boundary surface. 15, the left figure shows a cross-sectional view of the cradle guide of the embodiment shown in FIG. 11, and the right figure shows a cross-sectional view of the cradle guide of the embodiment shown in FIG. In FIG. 15, by providing a concave portion in the sintered metal member 81a, a convex portion corresponding to this is formed in the resin layer 81b to be injection molded. In addition, the said uneven | corrugated | grooved part may make the uneven | corrugated relationship reverse to what is shown in FIG. 15, and the shape can also be made into arbitrary shapes.

Although the cradle guide and the variable displacement axial piston pump of the variable displacement axial piston pump of the present invention have been described above, the embodiment of the present invention is not limited to this.

Examples of the sliding nut of the present invention will be described below.

[Examples A1 to A28 and Comparative Examples A1 to A3]
The materials for the sliding nut main body used in the examples and comparative examples are collectively shown in Table 1, and the raw materials for the resin layers used in the examples and comparative examples are collectively shown below. The melt viscosity of the PEK resin is a value measured at a Capillograph manufactured by Toyo Seiki Co., Ltd., φ1 × 10 (mm) capillary, a resin temperature of 380 ° C., and a shear rate of 1000 s ⁻¹ .
(1) PEK resin [PEK-1] manufactured by Victrex: PEEK 90P (melt viscosity: 105 Pa · s)
(2) PEK resin [PEK-2] manufactured by Victrex: PEEK 150P (melt viscosity 145 Pa · s)
(3) PEK-based resin [PEK-3] manufactured by Victrex: PEEK 450P (melt viscosity 420 Pa · s)
(4) PAN-based carbon fiber [CF-1] manufactured by Toray Industries, Inc .: Trading card MLD-30 (average fiber length 0.03 mm, average fiber diameter 7 μm)
(5) PAN-based carbon fiber [CF-2] manufactured by Toho Tenax Co., Ltd .: Besfite HTA-CMF0160-0H (fiber length 0.16 mm, fiber diameter 7 μm)
(6) Pitch-based carbon fiber [CF-3] manufactured by Kureha Co., Ltd .: Kureka M-101S (average fiber length 0.1 / 2 mm, average fiber diameter 14.5 μm)
(7) Pitch-based carbon fiber [CF-4] manufactured by Kureha Co., Ltd .: Kureka M-107S (average fiber length 0.7 mm, average fiber diameter 14.5 μm)
(8) Calcium carbonate powder [CaCO ₃ ] manufactured by Nittsu Kogyo Co., Ltd .: NA600 (average particle size 3 μm)
(9) Graphite [GRP] manufactured by Timcal Japan, Inc .: TIMREX KS6 (average particle size 6 μm)
(10) PTFE resin [PTFE] manufactured by Kitamura Co., Ltd .: KTL-610 (regenerated PTFE)

The raw materials were dry blended using a Henschel dry mixer at a blending ratio (volume%) shown in Table 2, and melt-kneaded using a twin screw extruder to produce pellets for the resin layer. With this pellet, under the conditions of a resin temperature of 380 ° C. to 400 ° C. and a mold temperature of 180 ° C., the inner diameter of the test cylinder of φ30 × φ35 × 20 (mm) made of the sliding nut body material shown in Table 1 A resin layer having a thickness of 0.2 to 1 mm was produced by insert molding.

(1) Shear adhesion strength test Resin layer-A test piece in which a in Table 2 is inserted with a thickness of 0.5 mm is used for the test cylinder inner diameter (φ30 x φ35 x 20 (mm)) in Table 1. Then, a shear adhesion strength test was conducted. The test cylinder was fixed, an axial shear force was applied to the inner diameter resin layer, and the load at which the resin layer peeled from the test cylinder was measured. Table 3 shows the value obtained by dividing the load by the apparent bonding area between the resin layer and the test cylinder, which is the shear adhesion strength. Table 3 also shows the presence or absence of cracks (none: ◯, present (one or more): x) in the test cylinder when 30 test pieces were produced by insert molding.

As shown in Table 3, in Examples A1 to A9, there was no cracking of the test cylinder during insert molding, and the shear adhesion strength was 1.5 MPa or more. In particular, in Examples A1 to A8 in which the density of the sintered metal is 0.7 to 0.9 of the theoretical density ratio of the materials, the shear adhesion strength is 2 MPa or more. In Example A10, in which the density of the sintered metal is the theoretical density ratio of 0.67, cracking of the test cylinder occurred during insert molding, but the resin layer can be formed by adhesion. On the other hand, in the steel machined product, the shear adhesion strength was a very low value (Comparative Example A1).

(2) Seizure resistance test On a test piece in which the resin layer shown in Table 2 is formed on the inner diameter (φ30 × φ35 × 20 (mm)) of the cylindrical body for testing, in which the material for the sliding nut body is made of the base material E shown in Table 1. The seizure resistance test was conducted using a radial type tester in oil. After running-in for 30 minutes under the oil supply conditions shown in Table 4, the time from oil supply stop / oil discharge to seizure was measured. The seizing time was the time until the test piece outer diameter temperature increased by 20 ° C. or the torque increased twice. Table 5 and Table 6 show the seizing time. In addition, the predetermined resin layer thickness described in Table 5 and Table 6 was formed by insert molding, and when it could not be formed, a thick product was injection molded and finished to a predetermined thickness by machining.

(3) Wear test About the same test piece as the seizure resistance test, the wear amount after operating for 30 hours under the oil supply conditions in Table 4 was measured using a radial in-oil tester. The amount of wear is shown in Tables 5 and 6.

(4) Melt viscosity Melt viscosities were measured at Capillograph manufactured by Toyo Seiki Co., Ltd., φ1 × 10 (mm) capillary, resin temperature 380 ° C., shear rate 1000 s ⁻¹ , and are shown in Table 5 and Table 6.

As shown in Tables 5 and 6, in Examples A11 to A23, the seizure time was 30 minutes or more, the wear amount was 10 μm or less, and the seizure resistance and the wear resistance were excellent. In Examples A11 to A15, A17 to A21, and A23 having a melt temperature of 200 Pa · s or less at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ , a predetermined resin layer could be formed by insert molding.

The comparative example A2 in which the nut body and the resin layer are integrated with resin is the comparative example A2, and the comparative example A3 in which the resin layer does not contain the solid lubricant or the reinforcing material, the seizure time is less than 1 minute, and the amount of wear is very high. It was a lot.

Examples of the sliding bearing for a compressor according to the present invention will be described below.

[Examples B1 to B20, Comparative Examples B1 to B4]
The sintered metal base material used in the examples and comparative examples is the same as the sliding nut body material shown in Table 1 above. For Examples and Comparative Examples, cylindrical base materials (φ30 × φ35 × 20 (mm)) of base materials A to I and K were prepared. Moreover, the raw material of the resin layer used for the Example and the comparative example is also the same as that used for the resin layer of the above-described sliding nut.

The raw material of the resin layer was dry blended using a Henschel dry mixer at a blending ratio (volume%) shown in Table 7, and melt-kneaded using a twin screw extruder to produce pellets for injection molding.

In the examples and comparative examples, the pellets were used, and a resin layer was formed on the inner diameter of the cylindrical base material by insert molding (resin temperature 380 ° C. to 400 ° C., mold temperature 180 ° C.), as shown in FIG. A cylindrical slide bearing (φ30 × φ35 × 20 (mm)) supporting a radial load was manufactured. The sintered dimension of the cylindrical base material is φ30 × φ35 × 20 (mm). In order to form a resin layer on the cylindrical substrate with a predetermined thickness, the inner surface of the cylindrical base material is turned and insert-molded. I did it. At the time of insert molding, nine pin gates were provided on the bearing end face so that the melt flow direction of the resin layer was perpendicular to the direction of motion of the sliding bearing.

In Examples B1 to B9 and Comparative Example B1, pellets of the resin composition a (Table 7) are used on the inner diameter (φ31 mm) of the cylindrical base material composed of the base materials A to I and the base material K (Table 1). A cylindrical sliding bearing with a resin layer thickness of 0.5 mm was manufactured by insert molding. In Examples B10 to B20 and Comparative Example B2, the resin layer thickness is determined by using pellets of the resin composition a to the resin composition h (Table 7) on the inner diameter of the cylindrical substrate made of the substrate E (Table 1). A cylindrical sliding bearing (φ30 × φ35 × 20 (mm)) of 0.2 to 1.0 mm was manufactured by insert molding.

Comparative Example B3 is a plain bearing made of a single resin injection molded into a shape of φ30 × φ35 × 20 (mm) using the resin composition a (Table 7). Comparative Example B4 is a three-layer sliding bearing (φ30 × φ35 × 20 mm, resin layer 0) in which a porous sintered layer (Cu + Sn) with a back metal (SPCC) is impregnated with a PTFE resin composition (10% by volume of carbon fiber). 0.05 mm).

(1) Shear adhesion strength test A shear adhesion strength test was conducted using the sliding bearings of Examples B1 to B9 and Comparative Example B1. In this shear adhesion strength test, a cylindrical substrate is fixed, an axial shear force is applied to the resin layer, a load at which the resin layer peels from the sintered metal substrate is measured, and the resin layer Table 8 shows the value obtained by dividing the apparent bonding area of the sintered metal substrate and the shear adhesion strength. In addition, 30 slide bearings were insert-molded, and the presence or absence of cracks in the cylindrical base material due to the molding pressure was confirmed.

As shown in Table 8, Examples B1 to B9 had no shearing of the sintered metal base material during insert molding, and had a shear adhesion strength of 1.5 MPa or more. In particular, Examples B1 to B8 using the base materials A to H in which the density of the sintered metal base material is 0.7 to 0.9 in terms of the theoretical density ratio of the materials had a shear adhesion strength of 2 MPa or more. . On the other hand, in the steel machined product, the shear adhesion strength was a very low value (Comparative Example B1).

(2) Seizure resistance test Using the slide bearings of Examples B10 to B20 and Comparative Examples B2 to B4, seizure resistance tests were performed with a radial in-oil tester. After running-in for 30 minutes under the oil supply conditions in Table 4 above, the time from oil supply stop / oil discharge to seizure was measured. The seizure time is the time required for the temperature of the outer diameter portion of the slide bearing to rise by 20 ° C. or the torque to double, and is shown in Tables 9 and 10.

(3) Wear test About the same cylindrical sliding bearing as the seizure resistance test, the wear amount after operating for 30 hours under the oil supply conditions shown in Table 4 above was measured using an in-oil radial type tester. The amount of wear is shown in Tables 9 and 10.

(4) Melt Viscosity The melt viscosity was measured at Toyo Seiki Co. Capiragraph, φ1 × 10 (mm) capillary, resin temperature 380 ° C., shear rate 1000 s ⁻¹ , and are shown in Table 9 and Table 10.

In Examples B10 to B20, the seizure time was 30 minutes or more, the wear amount was 10 μm or less, and the seizure resistance and the wear resistance were excellent.

In Comparative Example B2 in which the thickness of the resin layer exceeds 0.7 mm, the seizure time was less than 1 minute and the wear amount was very large. Since Comparative Example B3 was abnormally worn within 30 minutes, the seizure resistance test could not be performed. The sliding bearing of Comparative Example B4 seized immediately after a seizure time of less than 1 minute, and the amount of wear was large.

Examples of the cradle guide according to the present invention will be described below.

[Examples C1 to C21, Comparative Examples C1 to C4]
The sintered metal base material used in the examples and comparative examples is the same as the sliding nut body material shown in Table 1 above. Moreover, the raw material of the resin layer used for the Example and the comparative example is also the same as that used for the resin layer of the above-described sliding nut.

The raw material of the resin layer was dry blended using a Henschel dry mixer at a blending ratio (volume%) shown in Table 11, and melt-kneaded using a twin screw extruder to produce pellets for injection molding.

(1) Shear adhesion strength test (Examples C1 to C9, Comparative Example C1)
The shear adhesion strength test was performed using a cylindrical test piece. A cylindrical test piece was formed from a base material A to a base material I and a base material K described in Table 1 above, and a cylindrical base material of φ31 × φ35 × 20 (mm) was formed. A resin layer having a thickness of 0.5 mm was produced by insert molding (resin temperature: 380 ° C. to 400 ° C., mold temperature: 180 ° C.) using the pellets described above. At the time of insert molding, nine pin gates were provided on the end surface of the cylindrical test piece so that the melt flow direction of the resin layer was the axial direction of the cylindrical test piece.

In the shear adhesion strength test, this cylindrical test piece is fixed, an axial shear force is applied to the resin layer, the load at which the resin layer peels from the sintered metal substrate is measured, and the resin layer Table 12 shows the values obtained by dividing the apparent bonding area of the sintered metal substrate and the shear adhesion strength. In addition, 30 cylindrical test pieces were insert-molded, and the presence or absence of cracks in the cylindrical base material due to the molding pressure was confirmed.

As shown in Table 12, in Examples C1 to C9, the sintered metal base material was not cracked at the time of insert molding, and the shear adhesion strength was 1.5 MPa or more. In particular, in Examples C1 to C8 using the base materials A to H in which the density of the sintered metal base material is 0.7 to 0.9 of the theoretical density ratio of the materials, the shear adhesion strength is 2 MPa or more. It was. On the other hand, in the steel machined product, the shear adhesion strength was very low (Comparative Example C1).

(2) Seizure resistance test (Examples C10 to C20, Comparative Examples C2 to C3)
The seizure resistance test using an in-oil radial type tester was performed using a cylindrical test piece. The cylindrical test piece is manufactured in the same manner as the cylindrical test piece used for the shear adhesion strength test. Comparative Example C3 is a three-layer type slide bearing (φ30 × φ35 × 20 mm, resin, impregnated with PTFE resin composition (10% by volume of carbon fiber) in a porous sintered layer (Cu + Sn) with a back metal (SPCC) Layer 0.05 mm). After running-in for 30 minutes under the oil supply conditions in Table 4 above, the time from oil supply stop / oil discharge to seizure was measured. The seizing time was the time required for the outer diameter temperature of the cylindrical test piece to rise by 20 ° C. or the torque to double, and is shown in Table 13.

(3) Wear test About the same cylindrical test piece as the seizure resistance test, the wear amount after operating for 30 hours under the oil supply conditions shown in Table 4 above was measured using an in-oil radial type tester. The amount of wear is shown in Table 13.

(4) Melt Viscosity The melt viscosity at Toyo Seiki Co., Ltd. Capiragraph, φ1 × 10 (mm) capillary, resin temperature 380 ° C., shear rate 1000 s ⁻¹ was measured and shown in Table 13.

In Examples C10 to C20, the seizure time was 30 minutes or more, the wear amount was 10 μm or less, and the seizure resistance and the wear resistance were excellent. On the other hand, Comparative Example C2 in which the thickness of the resin layer exceeds 0.7 mm has a seizure time of less than 1 minute and a very large wear amount. Further, Comparative Example C3 was seized immediately after a seizure time of less than 1 minute, and the amount of wear was large.

(5) Reciprocating test (Example C21, Comparative Example C4)
In Example C21, a test piece was manufactured by forming a resin layer of a resin composition d (Table 11) by insert molding on the surface of a base material E (Table 1) molded to a length of 25 mm, a width of 50 mm, and a height of 20 mm. . About this test piece, the reciprocation test was done on the following conditions using the counterpart material made from an aluminum alloy, and the result was shown in Table 14. In insert molding, the melt flow direction of the resin layer was perpendicular to the direction of movement of the test piece. Comparative Example C4 is a three-layer slide bearing (plate thickness: 2.5 mm, resin, impregnated with PTFE resin composition (10% by volume of carbon fiber) in a porous sintered layer (Cu + Sn) with a back metal (SPCC). A test piece was manufactured by fixing a layer (0.05 mm) to a pedestal having a length of 25 mm, a width of 50 mm, and a height of 17 mm, and a similar reciprocating test was performed using an aluminum alloy mating member. The results are shown in Table 14. It was.

[Test conditions]
Testing machine: NTN reciprocating testing machine Surface pressure: 45MPa
Maximum excitation speed: 3m / min
Amplitude: + -50mm
Temperature: Room temperature (25 ° C)
Lubrication conditions: Oil lubrication Test time: 2000 reciprocations (initially, 500 times, 1000 times, coefficient of friction is measured)

Example C21 had a low coefficient of friction until the end of the test in the reciprocation test, and no change was observed in the state of the resin layer. As a result, it was confirmed that the cradle guide of the example can withstand long-term use of the variable displacement piston pump and can satisfy all of the load resistance, wear resistance and low friction characteristics of 30 MPa or more. . On the other hand, in Comparative Example C4, the test was stopped because the friction coefficient increased after 1000 reciprocations.

The slide screw device provided with the sliding nut of the present invention is easy to manufacture and has excellent sliding characteristics such as seizure resistance and wear resistance even under high load conditions. Can be suitably used as a sliding screw device used in the above.
Moreover, the sliding bearing for a compressor according to the present invention has high dimensional accuracy and is excellent in heat resistance, low friction, wear resistance, load resistance, and creep resistance while being easy to manufacture. Since the rotational torque can be stably obtained, it can be suitably used as a sliding bearing that rotatably supports a rotating member for driving the compression mechanism in a compressor for a room air conditioner or a car air conditioner. .
In addition, the cradle guide of the present invention is easy to manufacture and low in cost, but can satisfy all of the load resistance, wear resistance and low friction characteristics of 30 MPa or more, so that it can be used for construction machines such as hydraulic excavators and general industrial machines. The present invention can be suitably used in a variable displacement axial piston pump used for a hydraulic pump or a hydraulic motor provided as a hydraulic source.

1, 1a, 1b Radial plain bearing (slider bearing for compressor)
2, 22 Sintered

metal base material

3, 23 Resin layer 4 Fibrous filler 5, 5 ', 5''Compressor 6 Cylinder block 7 Front housing 8 Valve forming body 9 Rear housing 10 Crank chamber 11 Drive shaft 12 Lug Plate 13 Swash plate 14 Hinge mechanism 15 Cylinder bore 16 Piston 17 Shoe 18a, 18b Thrust rolling bearing 19 Suction chamber 20 Discharge chamber 21 Thrust sliding bearing (sliding bearing for compressor)
24 Plate 31a, 31b Radial plain bearing (slider bearing for compressor)
32 Drive shaft 33 Cylinder block 34 Front housing 35 Rear housing 36 Swash plate 37 Crank chamber 38 Shoe 39 Piston 40 Valve forming body 41 Suction chamber 42 Discharge chamber 43 Bolt insertion hole 44 Thrust rolling bearing 51 Fixed scroll 52 Center housing 53 Motor housing 54

Shaft

55, 56, 59 Radial plain bearing (slider bearing for compressor)
57 Balance weight 58 Movable scroll 60 Bush 61 Sealed chamber 62 Stator 63 Rotor 64 Discharge chamber 65 Motor chamber 66 Seal member 67 Low pressure chamber 68 Space 71 Slide screw device 72 Screw shaft 73 Sliding nut 81 Cradle guide 82 Piston 83 Cradle 84

Fibrous Filler

85, 86 Housing 87 Rotating shaft 88 Cylinder block 89

Valve plate

90, 93 Pressing spring 91 Retainer 92 Shoe 94 Hydraulic controller 95 Cylinder

Claims

In the sliding screw device, a sliding nut that moves relatively while sliding on the axis of the screw shaft as the screw shaft rotates,
In the sliding nut, the nut body is made of a sintered metal, and a resin layer of a resin composition having a synthetic resin as a base resin is formed as a thread groove portion on the surface of the female thread portion that is screwed to the screw shaft in the nut body. A sliding nut characterized by
The sliding nut according to claim 1, wherein the resin layer is a resin layer that is injection-molded over the nut body.
The sliding nut according to claim 1, wherein the synthetic resin is an aromatic polyether ketone resin.
The sliding nut according to claim 1, wherein the resin layer has a thickness of 0.1 to 1.5 mm.
The sliding nut according to claim 3, wherein the resin composition contains a fibrous filler.
The sliding nut according to claim 5, wherein the fibrous filler is a fibrous filler having an average fiber length of 0.02 to 0.2 mm.
The sliding nut according to claim 1, wherein the sintered metal of the nut body has a theoretical density ratio of 0.7 to 0.9.
4. The sliding nut according to claim 3, wherein the resin composition is a resin composition having a melt viscosity of 50 to 200 Pa · s at a resin temperature of 380 ° C. and a shear rate of 1000 s −1 .
6. The resin composition according to claim 5, wherein the fiber composition contains 5 to 30% by volume of carbon fiber and 1 to 30% by volume of polytetrafluoroethylene resin as the fibrous filler with respect to the entire resin composition. Sliding nut.
The sliding nut according to claim 9, wherein the carbon fiber is a PAN-based carbon fiber.
A sliding screw device comprising a screw shaft and a sliding nut that moves relatively while sliding on the shaft of the screw shaft as the screw shaft rotates.
The sliding screw device according to claim 1, wherein the sliding nut is the sliding nut according to claim 1.
The sliding screw device according to claim 11, wherein the sliding screw device is lubricated with oil or grease.
A sliding bearing for a compressor that rotatably supports a rotating member for driving a compression mechanism of the compressor,
The sliding bearing has a sliding surface of a resin layer made of a resin composition based on an aromatic polyether ketone-based resin on a sintered metal base,
A sliding bearing for a compressor, wherein the resin layer is integrally provided by injection molding on the surface of the sintered metal base material with a thickness of 0.1 to 0.7 mm.
The resin composition includes a fibrous filler, and in the resin layer, the fibrous filler is oriented so that the length direction of the fiber intersects 45 to 90 degrees with respect to the sliding direction of the sliding bearing. The sliding bearing for a compressor according to claim 13, wherein the sliding bearing is for a compressor.
15. The resin composition contains 5 to 30% by volume of carbon fiber and 1 to 30% by volume of polytetrafluoroethylene resin as the fibrous filler with respect to the entire resin composition. The sliding bearing for a compressor as described.
The slide bearing is a bearing that supports the rotating member in a radial direction, and is arranged so as to pressure-isolate an internal space in the housing of the compression mechanism. Slide bearing for compressor.
The sliding bearing is a bearing that supports the rotating member in a thrust direction, and is disposed on a side that receives a compression reaction force generated in the compression mechanism via the rotating member. The sliding bearing for a compressor as described.
A compressor comprising a sliding bearing that rotatably supports a rotating member for driving a compression mechanism, wherein the sliding bearing is a sliding bearing for a compressor according to claim 13. .
A cradle guide that slides in contact with a cradle that adjusts a piston stroke in a variable displacement axial piston pump and holds the cradle so that it can swing.
The cradle guide has a sintered metal member and a resin layer made of a resin composition based on an aromatic polyetherketone resin,
The variable capacity type axial is characterized in that the resin layer is integrally formed by injection molding at a thickness of 0.1 to 0.7 mm on at least a surface of the sintered metal member that is in sliding contact with the cradle. Cradle guide for piston pumps.
The resin composition includes a fibrous filler, and in the resin layer, the fibrous filler is oriented so that the length direction of the fiber intersects 45 to 90 degrees with respect to the sliding direction of the cradle guide. The cradle guide for a variable displacement axial piston pump according to claim 19.
The resin composition contains 5 to 30% by volume of carbon fiber and 1 to 30% by volume of polytetrafluoroethylene resin as the fibrous filler with respect to the entire resin composition. A cradle guide for the described variable displacement axial piston pump.
20. The cradle guide of a variable displacement axial piston pump according to claim 19, wherein the sintered metal member is a cradle guide body.
20. The variable displacement axial piston pump according to claim 19, wherein the cradle guide has a cradle guide body made of molten metal, and the sintered metal member is installed in the cradle guide body. Cradle guide.
A variable displacement axial piston pump comprising the cradle guide according to claim 19.