JP2006097720A - Bearing and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical bearing 70 manufacturable at low cost and having excellent sliding property due to close and firm adhesion of resin containing fluorine being a solid lubricant and to provide its manufacturing method. <P>SOLUTION: Formation treatment is applied to a basic material for forming the cylindrical bearing 70 to make a surface coarse. At this time, surface coarseness Ra is 3.7 μm. Solid lubricating layer containing fluorine containing resin is formed on its surface. After polishing the surface of the solid lubricating layer, the bearing 70 is pressed into the inside of a protruding part 53 of a movable scroll 50 being a housing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bearing and a manufacturing method thereof, and more particularly to a cylindrical bearing and a manufacturing method thereof.

  Conventionally, a cylindrical low-friction sliding bearing has been manufactured by rolling a flat plate having a lubricating layer on its surface into a cylindrical shape (see, for example, Patent Documents 1 and 2). Such a bearing includes a skin pass step of rolling a plate-like material provided with a back metal and a lining layer integrally provided on the back metal, a bending step of bending the plate-like material into a cylindrical shape after the skin pass step, After the bending step, the cutting process is performed by cutting and finishing the inner peripheral surface of the lining layer.

However, even if the inner peripheral surface (surface) of the lining layer is finally cut and finished smooth, the stress applied during the skin pass process and the bending process is released due to aging or thermal change, and the inner peripheral surface is uneven. It will occur. When such unevenness occurs, the stable operation of the drive shaft is hindered. In the technique described in Patent Document 1, the cutting process is performed after the stress applied to the lining layer is released during the skin pass process so that such unevenness does not occur.
Japanese Patent Laid-Open No. 11-277168 JP 2002-53673 A

  However, the technique described in Patent Document 1 has three steps, a skin pass step, a bending step, and a cutting step, and the skin pass step further forms a sintered layer by placing lead bronze powder on the back metal and sintering it. It is divided into a process, a process of impregnating a sintered layer with a heat-resistant synthetic resin to form a lining layer, and a rolling process of rolling a back metal having a lining layer. As described above, since the technique disclosed in Patent Document 1 requires many steps, there is a problem that the manufacturing time is increased and the manufacturing cost is increased. And since a rolling process and a bending process exist, the heat resistant synthetic resin which is a solid lubricant will be easily peeled off from the sintered layer. In addition, since the flat plate having the lining layer is bent into a cylindrical shape, there is a problem that the joint portion becomes a step or the friction coefficient changes at the joint portion. These problems are also included in the technique described in Patent Document 2.

  The present invention has been made in view of the above points, and the object of the present invention is to produce a low-cost fluorine-containing resin that is a solid lubricant and has excellent slidability. The object is to provide a cylindrical bearing (70) and a method of manufacturing the same.

  In order to achieve the above object, a first invention of the present application is a cylindrical bearing (70), comprising a metal base material and a solid lubricating layer provided on the surface of the base material. It is characterized by. The second invention of the present application is a method for manufacturing a bearing (70), and includes a roughening step of roughening the surface of the substrate.

Specifically, the first invention of the present application is directed to a cylindrical bearing (70), and the following solution is taken. That is, the invention according to claim 1 is a cylindrical bearing (70). And a cylindrical base material made of metal and a solid lubricating layer provided on the inner surface of the base material, the inner surface of the base material having an arithmetic average height Ra of the contour curve Is roughened with a surface roughness greater than 0.5 μm and less than 10 μm, and the solid lubricating layer contains a fluorine-containing resin.

  With the above configuration, in the invention described in claim 1, the inner surface of the base material and the layer containing the fluorine-containing resin are firmly adhered, and the layer containing the fluorine-containing resin is hardly slipped from the base material. A cylindrical bearing (70) with excellent dynamic performance is realized.

  The invention according to claim 2 is the bearing (70) according to claim 1, which is press-fitted into the housing.

  With the above configuration, the invention according to claim 2 realizes a cylindrical bearing (70) press-fitted into the housing and having excellent sliding performance.

  The invention according to claim 3 is characterized in that the inner surface of the base material is subjected to a roughening treatment in which the arithmetic average height Ra of the contour curve is a surface roughness greater than 0.75 μm and less than 10 μm. Item 3. The bearing (70) according to item 1 or 2.

  According to the above configuration, in the invention of claim 3, the inner surface of the base material and the layer containing the fluorine-containing resin are adhered very firmly, and the loss of the layer containing the fluorine-containing resin from the substrate can be reliably prevented. .

  The invention according to claim 4 is the bearing (70) according to any one of claims 1 to 3, wherein the roughening treatment is a chemical conversion treatment.

  With the above configuration, in the invention of claim 4, the roughening process can be performed with high accuracy and good reproducibility.

  The invention according to claim 5 is the bearing (70) according to any one of claims 1 to 4, wherein the solid lubricating layer contains a polyamideimide resin.

  According to the above configuration, in the invention of claim 5, the layer containing the fluorine-containing resin can be made difficult to break, and can be more firmly adhered to the metal substrate.

  Next, the second invention of the present application is directed to the manufacturing method of the bearing (70), and the following solution is taken.

  That is, the invention described in claim 6 is a step of forming a cylindrical base material made of metal, a roughening step of roughening at least an inner surface of the base material, and the roughening step. And forming a solid lubricating layer containing a fluorine-containing resin on the inner surface of the substrate.

  According to the above configuration, in the invention of claim 6, the solid lubricating layer can be firmly adhered to the base material, and the bearing (70) can be manufactured with fewer steps.

  In the seventh aspect of the present invention, in the roughening step, the inner surface of the base material has a surface roughness with an arithmetic mean height Ra of the contour curve greater than 0.5 μm and less than 10 μm due to the roughening. The method for manufacturing a bearing (70) according to claim 6.

  With the above configuration, in the invention of claim 7, the sliding performance with which the inner surface of the substrate and the layer containing the fluorine-containing resin are firmly adhered, and the layer containing the fluorine-containing resin is hardly lost from the substrate. It is possible to manufacture a cylindrical bearing (70) excellent in the above.

  According to an eighth aspect of the present invention, in the roughening step, the arithmetic average height Ra of the contour curve is greater than 0.75 μm and less than 10 μm by roughening the inner surface of the substrate. The method for manufacturing a bearing (70) according to claim 6.

  According to the above configuration, in the invention of claim 8, the inner surface of the base material and the layer containing the fluorine-containing resin adhere very firmly, and the loss of the layer containing the fluorine-containing resin from the substrate is reliably prevented. Bearing (70) can be manufactured.

  The invention according to claim 9 is the method for manufacturing the bearing (70) according to any one of claims 6 to 8, wherein in the roughening step, roughening is performed by chemical conversion treatment.

  With the above configuration, in the invention of claim 9, the roughening process can be performed with high accuracy and good reproducibility.

  The invention according to claim 10 is the method for manufacturing the bearing (70) according to any one of claims 6 to 9, further comprising a press-fitting step of press-fitting the base material inside the housing.

  With the above configuration, in the invention of claim 10, a cylindrical bearing (70) press-fitted into the housing and having excellent sliding performance can be manufactured at a low cost by a small number of steps.

  The invention according to claim 11 is the method for manufacturing the bearing (70) according to claim 10, further comprising a step of polishing the surface of the solid lubricant layer before the press-fitting step.

  With the above configuration, in the invention of claim 11, the number of manufacturing steps can be reduced and the cost can be reduced.

  According to invention of Claim 1, the adhesiveness of a metal base material and a fluorine-containing resin becomes high, and the outstanding slidability is shown.

  According to the second aspect of the present invention, a cylindrical bearing (70) press-fitted into the housing and having excellent sliding performance is realized.

  According to invention of Claim 3, the adhesiveness of a metal base material and a fluorine-containing resin becomes high reliably, and shows the outstanding slidability.

  According to the fourth aspect of the present invention, the surface roughening of the metal substrate can be performed with high accuracy and reproducibility.

  According to invention of Claim 5, the layer containing a fluorine-containing resin can be hardened, and the adhesiveness of this layer to the metal base material can be improved more.

  According to the sixth aspect of the present invention, the cylindrical bearing (70) exhibiting excellent slidability can be manufactured with a small number of steps.

  According to the seventh aspect of the present invention, the cylindrical bearing (70) having high adhesion between the metal substrate and the fluorine-containing resin and excellent slidability can be produced with a small number of steps.

  According to the eighth aspect of the present invention, the cylindrical bearing (70) can be manufactured with a high degree of adhesiveness between the metal base material and the fluorine-containing resin with a high number of steps.

  According to the ninth aspect of the present invention, the surface roughening of the metal substrate can be performed with high accuracy and reproducibility.

  According to the tenth aspect of the present invention, a cylindrical bearing (70) press-fitted into the housing and having excellent sliding performance can be manufactured with a small number of steps.

  According to the eleventh aspect of the present invention, the cylindrical bearing (70) can be manufactured at low cost by reducing the number of manufacturing steps.

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

(Embodiment 1)
The scroll compressor (10) of the present embodiment is provided in a refrigerant circuit of a refrigeration apparatus and is used to compress a gas refrigerant that is a fluid.

<Overall configuration of scroll compressor>
As shown in FIG. 1, the scroll compressor (10) is configured in a so-called hermetically sealed type. The scroll compressor (10) includes a casing (11) formed in a vertically long and cylindrical sealed container shape. In the casing (11), a lower bearing member (30), an electric motor (35), and a compression mechanism (40) are arranged in order from the bottom to the top. Further, a drive shaft (20) extending vertically is provided inside the casing (11).

  The inside of the casing (11) is partitioned up and down by a fixed scroll (60) of the compression mechanism (40). Inside the casing (11), the space above the fixed scroll (60) is the first chamber (12), and the space below it is the second chamber (13).

  A suction pipe (14) is attached to the body of the casing (11). The suction pipe (14) opens into the second chamber (13) in the casing (11). On the other hand, a discharge pipe (15) is attached to the upper end of the casing (11). The discharge pipe (15) opens into the first chamber (12) in the casing (11).

  The drive shaft (20) includes a main shaft portion (21), a flange portion (22), and an eccentric portion (23). The flange portion (22) is formed at the upper end of the main shaft portion (21), and has a disk shape with a larger diameter than the main shaft portion (21). On the other hand, the eccentric portion (23) protrudes from the upper surface of the flange portion (22). The eccentric portion (23) has a cylindrical shape with a smaller diameter than the main shaft portion (21), and the shaft center is eccentric with respect to the shaft center of the main shaft portion (21).

  The main shaft portion (21) of the drive shaft (20) passes through the frame member (41) of the compression mechanism (40). The main shaft portion (21) is supported by the frame member (41) via a roller bearing (42). Further, the flange portion (22) and the eccentric portion (23) of the drive shaft (20) are located in the first chamber (12) above the frame member (41).

  A slide bush (25) is attached to the drive shaft (20). The slide bush (25) includes a cylindrical portion (26) and a balance weight portion (27), and is placed on the flange portion (22). The eccentric part (23) of the drive shaft (20) is rotatably inserted into the cylindrical part (26) of the slide bush (25).

  The lower bearing member (30) is located in the second chamber (13) in the casing (11). The lower bearing member (30) is fixed to the frame member (41) by bolts (32). The lower bearing member (30) supports the main shaft portion (21) of the drive shaft (20) via the ball bearing (31).

  An oil supply pump (33) is attached to the lower bearing member (30). The oil pump (33) is engaged with the lower end of the drive shaft (20). The oil supply pump (33) is driven by the drive shaft (20), and sucks the refrigeration oil accumulated at the bottom of the casing (11). The refrigerating machine oil sucked up by the oil supply pump (33) is supplied to the compression mechanism (40) and the like through a passage formed in the drive shaft (20).

  The electric motor (35) includes a stator (36) and a rotor (37). The stator (36) is fixed to the frame member (41) by bolts (32) together with the lower bearing member (30). On the other hand, the rotor (37) is fixed to the main shaft portion (21) of the drive shaft (20).

  A power feeding terminal (16) is attached to the body of the casing (11). The terminal (16) is covered with a terminal box (17). Electric power is supplied to the electric motor (35) through the terminal (16).

<Configuration of compression mechanism>
The compression mechanism (40) includes a movable scroll (50) and an Oldham ring (43) in addition to the fixed scroll (60) and the frame member (41). The compression mechanism (40) has a so-called asymmetric scroll structure.

  The movable scroll (50) includes a movable side flat plate portion (51), a movable side wrap (52), and a protruding portion (53). The movable side flat plate portion (51) is formed in a slightly thick disk shape. The protruding portion (53) is formed integrally with the movable side flat plate portion (51) so as to protrude from the lower surface of the movable side flat plate portion (51). The protrusion (53) is located substantially at the center of the movable side flat plate portion (51). The cylindrical portion (26) of the slide bush (25) is inserted into the protruding portion (53). That is, the movable scroll (50) is engaged with the eccentric portion (23) of the drive shaft (20) via the slide bush (25).

  The movable side wrap (52) is erected on the upper surface side of the movable side flat plate portion (51) and is formed integrally with the movable side flat plate portion (51). The movable side wrap (52) is formed in a spiral wall shape having a constant height.

  The movable scroll (50) is placed on the frame member (41) via the Oldham ring (43). Two pairs of keys are formed on the Oldham ring (43). The Oldham ring (43) has a pair of keys engaged with the movable side flat plate portion (51) of the movable scroll (50) and the remaining pair of keys engaged with the frame member (41). The orbiting scroll (50) engaged with the eccentric portion (23) of the drive shaft (20) is restricted to rotate by the Oldham ring (43) and performs only the revolving motion.

  As shown in FIG. 1, the fixed scroll (60) includes a fixed-side flat plate portion (61), a fixed-side wrap (63), and an edge portion (62). The fixed-side flat plate portion (61) is formed in a slightly thick disk shape. The diameter of the fixed flat plate portion (61) is substantially equal to the inner diameter of the casing (11). The edge portion (62) is formed in a wall shape extending downward from the peripheral portion of the fixed-side flat plate portion (61). The fixed scroll (60) is fixed to the frame member (41) by a bolt (44) in a state where the lower end of the edge (62) is in contact with the frame member (41). And the fixed scroll (60) partitions the inside of the casing (11) into the first chamber (12) and the second chamber (13) by the edge (62) being in close contact with the casing (11).

  The fixed side wrap (63) is erected on the lower surface side of the fixed side flat plate portion (61), and is formed integrally with the fixed side flat plate portion (61). The fixed-side wrap (63) is formed in a spiral wall shape having a constant height, and has a length of about 3 turns. In the fixed wrap (63), almost the entire inner surface is the inner wrap surface (64), while the outer wrap surface (65) is the length of about 2 turns from the start of the outer surface. It has become.

  Of the lower surface of the fixed-side flat plate portion (61), the portion sandwiched between the inner wrap surface (64) and the outer wrap surface (65) is a tooth bottom surface (66). The tooth bottom surface (66) is in sliding contact with the tip of the movable side wrap (52). Further, a discharge port (67) is formed in the vicinity of the winding start of the fixed side wrap (63) in the fixed side flat plate portion (61). The discharge port (67) passes through the fixed-side flat plate portion (61) and opens into the first chamber (12).

  As described above, the scroll compressor (10) of the present embodiment is provided in the refrigerant circuit of the refrigerator. In this refrigerant circuit, the refrigerant circulates to perform a vapor compression refrigeration cycle. At that time, the scroll compressor (10) sucks and compresses the low-pressure gas refrigerant from the evaporator, and sends the compressed high-pressure gas refrigerant to the condenser.

  When the scroll compressor (10) is operated, the cylindrical portion (26) of the slide bush (25) and the protruding portion (53) of the movable scroll (50) slide. In the present embodiment, a bearing (70) is provided on this sliding portion. The bearing (70) has a cylindrical shape and is made of a sliding member having iron as a base material and a lubricant layer provided on the surface (inner surface side). The inner surface of the bearing (70) provided with the lubricant layer slides with the outer surface of the cylindrical portion (26) of the slide bush (25).

  The surface of the base material of the bearing (70) has a surface roughness Ra of 3.7 μm due to the chemical conversion treatment. Then, a lubricant in which a polyamideimide resin (hereinafter referred to as PAI), polytetrafluoroethylene (hereinafter referred to as PTFE), and a tetrafluoroethylene-hexafluoropropylene copolymer resin (hereinafter referred to as FEP) are mixed is applied thereon. Thus, a lubricant layer having a thickness of about 100 μm is formed. Here, the surface roughness Ra is the arithmetic average height Ra of the contour curve defined in JIS B 0601-2001. If the surface roughness Ra is displayed after this, it is determined by JIS. It shall represent the prescribed arithmetic average height Ra.

  By disposing the bearing (70) having such a configuration in the inside (inside) of the projecting portion (53) of the movable scroll (50) as the housing, the cylindrical portion (26) of the slide bush (25) and the bearing (70 ) Can slide for a very long time with a low coefficient of friction even if they slide while exposed to the refrigerant.

《Examination of sliding parts》
In the following, a description will be given of the examination performed on the sliding portion (the inner surface of the cylinder) of the cylindrical bearing (70). Note that the following sliding performance was examined based on sliding performance on a flat surface.

  The fluorine-containing resin has a low coefficient of friction with a metal and excellent slidability, but has poor adhesion with a metal base material and is easily peeled off from the metal base material. Accordingly, the inventors of the present application first studied how the surface roughness of the base material can improve the adhesion of the fluorine-containing resin to the base material.

  The examination method was a limit surface pressure test using a ring / disk test piece as shown in FIG. The limit surface pressure test is a test for evaluating the adhesion of the lubricant to the base material. A ring made of SUJ2 (according to JIS G4805-1990) is rotated at a constant speed, and the evaluation test piece (disk) is rotated on its axis of rotation. And press against the ring for evaluation. In the test, the pressing load is increased step by step while measuring the torque applied to the ring. Then, the load at which the torque suddenly increases is converted into a surface pressure, and the product of the surface pressure and the rotation speed is defined as a limit PV (limit surface pressure / velocity product) as an adhesion evaluation index. That is, when the lubricant of the test piece is peeled off from the base material, the friction coefficient between the ring and the disk is suddenly increased and the torque is rapidly increased. Therefore, the adhesion can be evaluated by the limit PV. The larger the limit PV, the better the adhesion. This test was performed in the air and without any lubricating oil between the ring / disk.

  The test piece was prepared by subjecting the surface of the iron base material to a surface roughening treatment by a chemical conversion treatment, and further forming a lubricant layer containing a fluororesin on the surface. The surface roughness Ra of the substrate was adjusted by changing the treatment conditions of the chemical conversion treatment. Here, manganese phosphate was used for the chemical conversion treatment. The lubricant layer was formed from a resin mixture having a composition ratio of PAI / FEP / PTFE = 70/24/6. The thickness of the lubricant layer was about 100 μm. The lubricant layer was formed by applying a resin mixture, firing, and then polishing the surface.

  FIG. 3 is a graph showing the relationship between the surface roughness Ra of the substrate and the limit PV. Here, the base material Ra shown in FIG. 3 is an arithmetic average height Ra of the contour curve defined in JIS B0601-2001 on the base material surface. As can be seen from this graph, when Ra is less than 0.5 μm, the limit PV is less than 0.4 MPa · m / s, but when Ra exceeds 0.5 μm, the limit PV is less than 0.4 MPa · m / s. Therefore, it has sufficient adhesion for general sliding member applications. It is preferable that the limit PV is 1 MPa · m / s or more (Ra 0.75 μm or more) because sufficient adhesion can be maintained even if the environment changes. In applications that require more adhesion, the limit PV should be 1.0 MPa · m / s or more (Ra 0.75 μm or more), preferably 1.5 MPa · m / s or more (Ra 0.85 μm or more). ).

  On the other hand, if the surface roughness Ra is too large, the maximum height Rz of the surface roughness is also increased, so that a part of the base material protrudes from the surface of the lubricant layer. Further, in order to increase the surface roughness Ra, it is necessary to carry out a chemical conversion treatment for a long time, which increases the cost, and the unevenness on the surface of the substrate formed by the chemical conversion treatment tends to collapse. For these reasons, the surface roughness Ra is preferably less than 10 μm, and more preferably 5 μm or less because it can be produced at low cost.

  Next, the surface roughness Ra of the iron base material is set to 3.7 μm by chemical conversion treatment, the lubricant layer having the above composition ratio is applied to the surface of the base material, and further compared with Sample B of this embodiment, which is fired / polished. Sample A (a porous bronze sintered body (surface roughness Ra of 30 μm or more) formed on an iron plate and impregnated with a fluororesin) was subjected to a sliding performance evaluation test. Comparative sample A is a conventional sliding member used in an air conditioning scroll compressor.

  FIG. 5 shows the result of a limit surface pressure test without lubricating oil in the air. Comparative sample A seized when the surface pressure reached about 5.5 MPa, but sample B did not seize even when the surface pressure reached the upper limit of 7 MPa of the testing machine.

  FIG. 6 shows the results of a wear amount test without lubricating oil in the air. The test condition is a condition of sliding for 1 hour at a surface pressure of 2.8 MPa and a sliding speed of 1 m / s. The comparative sample A had a wear amount of about 45 μm, but the sample B has a very small wear amount of 10 μm, indicating that it is excellent.

  Furthermore, the result of the sliding test in a refrigerant | coolant is shown in FIG. In general, in an air-conditioning compressor, a refrigerant (HFC refrigerant) and lubricating oil are mixed at a ratio of 65:35 in order to suppress wear of the sliding portion. In this test, the mixing ratio of lubricating oil ( Data were collected by changing (concentration). The HFC refrigerant contains a fluorine-containing substance. In the sliding test shown in FIG. 4, the vertical axis represents the amount of wear when sliding for 2 hours at a surface pressure of 3 MPa and a sliding speed of 2 m / s. The horizontal axis indicates the ratio of the lubricating oil mixed in the refrigerant.

  Comparative sample A is a conventional member used in the sliding portion, but the wear amount was 13 μm at a normal lubricating oil concentration of 35%, and when the lubricating oil concentration was 10%, the wear amount increased to 24 μm. On the other hand, sample B has a lubricating oil concentration of 10% and a wear amount of 2 μm, and even if the lubricating oil concentration is 0%, that is, the refrigerant is 100%, the wear amount is very small as 4 μm. The amount of wear at 100% is smaller than the amount of wear of the comparative sample A at the normal lubricating oil concentration (35%).

  As is clear from the above results, the sample B of this embodiment hardly wears even when the lubricating oil concentration is 0%, so there is no need to mix the lubricating oil in the refrigerant, and the cooling efficiency can be greatly improved. it can. Since the fluorine-containing resin is present on the surface of the sliding member, it is well adapted to the refrigerant containing the fluorine-containing substance, and the sliding performance is improved. Further, at the time of starting the compressor or during a transition, it can be considered that the sliding portion is in a completely dry state where no refrigerant exists, but even in such a case, the sample B of the present embodiment has excellent sliding properties. Demonstrate performance. Such excellent sliding performance is exhibited only when the adhesion between the substrate and the fluorine-containing resin layer (lubricant layer) is high. That is, in sample B, the surface roughness Ra of the base material surface is in an appropriate range, so the adhesion between the base material and the fluororesin layer is very excellent, and therefore excellent sliding performance can be exhibited. is there.

  Next, the composition of the layer containing the fluororesin will be described.

  The main component of the layer containing a fluorine-containing resin is preferably composed of 15% by mass to 35% by mass of a fluorine resin and 65% by mass to 85% by mass of a polyamideimide resin. The fluororesin in the main component is preferably composed of FEP and PTFE. In this fluororesin, it is preferable that the ratio of FEP is larger than that of PTFE. Specifically, the mass ratio of FEP and PTFE in this fluororesin is preferably FEP: PTFE = 7: 3 to 99: 1, and it is desirable that the FEP is “9” and the PTFE is “1”.

  When polyamideimide resin is mixed as described above, the property of polyamideimide resin, which is excellent in impact resistance, can be used, and the resin film has high impact resistance and is difficult to peel off on the sliding surface of the constituent member. Can be formed. In addition, since the polyamideimide resin has a characteristic of high hardness, the resin film is relatively hard and difficult to wear.

  In addition to the main component composed of the fluororesin and the polyamideimide resin, the layer containing the fluororesin may contain a pigment such as carbon as a colorant and other additives. The addition amount of such an additive is set to such an extent that the performance of the layer containing the fluorine-containing resin and the adhesion to the substrate are not adversely affected. For example, carbon as an additive must be set to 3% by mass or less of the fluororesin, preferably 1% by mass or less, and more preferably 0.5% by mass or less.

  Further, the thickness of the layer containing the fluororesin is preferably 35 μm or more and 120 μm or less. If it is thinner than 35 μm, the sliding performance may be inferior, and if it is thicker than 120 μm, the manufacturing cost increases. The thickness of this layer is more preferably 50 μm or more and 105 μm or less in terms of sliding performance and cost. In addition, the thickness of a layer here is an average thickness, Comprising: You may be the thickness outside this range locally.

<Production method of bearing (70)>
The method for manufacturing the bearing (70) of the present embodiment will be described in comparison with a conventional method for manufacturing a bearing.

  FIG. 7 is a schematic process diagram showing the manufacturing process of the conventional bearing (118). FIG. 7 shows the process in two stages. The process starts from the upper left and proceeds to the right, moves from the upper right edge to the lower left edge, and proceeds from the lower left edge to the right.

  The conventional bearing (118) is manufactured from the step of spraying metal powder such as bronze on the surface of a metal plate with a metal powder spraying device.

  Next, the metal powder is sintered in a sintering furnace to form a sintered metal layer on the plate material. Since this sintered metal layer is porous, the sintered metal layer is impregnated with a fluororesin and the surface of the sintered metal is covered with the fluororesin.

  Then, the fluororesin is fired in a firing furnace and rolled in a sizing (skin pass) process. And it press-cuts with a cutting machine and makes it the flat plate of desired size.

  Next, as shown in the lower left of FIG. 7, the flat plate is formed into a cylindrical bearing (118) by pressing. At this time, pressing is performed so that the fluororesin layer becomes the inner surface of the cylinder. The bearing (118) is press-fitted into the cylindrical housing (119) (shown from the side of the cylinder in the figure) to form a housing (119) into which the bearing (118) is press-fitted. Then, the fluororesin layer on the inner surface of the bearing (118) is polished (inner peripheral processing) so that the inner diameter of the bearing (118) is substantially the same as the outer diameter of the shaft. This completes the bearing (118). Here, the shape of the housing (119) is omitted in a simple cylindrical shape, but it is actually a complicated shape like the movable scroll (50).

  On the other hand, the manufacturing process of the bearing (70) of this embodiment starts from an iron cylindrical bush as shown in FIG. This iron cylindrical bush is immersed in a chemical conversion bath, and the surface of the cylindrical bush is roughened by chemical conversion. As the chemical for the chemical conversion treatment, a phosphate (for example, manganese phosphate) is used. By this roughening, the surface roughness Ra of the inner surface of the cylindrical bush is set to 3.7 μm. Here, the entire cylindrical bush is immersed in a bath and the outer surface is roughened, but at least the inner surface may be roughened.

  Next, a resin is applied to the inner surface of the cylindrical bush that has undergone the roughening treatment. This resin was a resin mixture having a composition ratio of PAI / FEP / PTFE = 70/24/6. After application of the resin, the resin is baked in a baking furnace. Thus, a lubricant layer made of a resin containing a fluorine-containing resin is provided on the inner surface of the cylindrical bush, so that a cylindrical bearing (70) is obtained.

  Then, the inner surface of the cylindrical bearing (70) is polished (inner peripheral processing) to make the inner diameter of the bearing (70) substantially the same as the outer diameter of the shaft.

  Thereafter, the bearing (70) is press-fitted into the projecting portion (53) of the movable scroll (50) as a housing to complete the housing. Here, only the projecting portion (53) is shown in a cylindrical shape, and most of the movable scroll (50) is omitted.

  Comparing the above-described conventional manufacturing method with the manufacturing method of the present embodiment, the bearing (70) of the present embodiment can be roughened, resin coated, fired, inner periphery processed, press-fitted if a cylindrical bush is prepared. While the conventional bearing (118) can be manufactured in five steps, the present embodiment has nine steps of metal powder coating, metal powder sintering, fluororesin impregnation, firing, sizing, cutting, press bending, press-fitting, and inner peripheral processing. The number of processes is about twice as long as that, and time and cost are increased accordingly. Further, there are the following two major differences between the two manufacturing methods.

  One is the difference in the order of performing the press-fitting and the inner peripheral machining. In the conventional manufacturing method, the housing is first press-fitted and then the inner periphery is processed. This is because, since the material has characteristics and joints, the dimensions and shape accuracy cannot be set to the desired dimensions and shape accuracy if the inner circumference is first processed. For this reason, it is necessary to perform inner circumference processing after press-fitting into a large and complicated housing such as the movable scroll (50), and therefore inner circumference processing becomes difficult, and a large special processing machine is required. Become. On the other hand, in the manufacturing method of the present embodiment, a substrate having high rigidity can be selected, and therefore press-fitting can be performed after the inner periphery processing. For this reason, it is only necessary to set the cylindrical bush on the processing machine in the inner peripheral processing, and the inner peripheral processing can be easily performed with a simple processing machine, and the cost of the inner peripheral processing is reduced compared to the conventional manufacturing method. It can be greatly reduced.

  The second is the presence or absence of a joint. In the conventional manufacturing method, since the flat plate is rounded, a joining portion where the end portions of the flat plate are joined is generated. This portion is easily deformed when a force is applied, and the friction coefficient may be different from other portions. However, since the bearing (70) manufactured by the manufacturing method of this embodiment does not have a joint, such a problem does not occur.

  In this embodiment, in the bearing (70) which is a cylindrical sliding member, the surface roughness Ra on the inner side of the base material is set to a predetermined size, and a layer containing a fluorine-containing resin is formed on the surface as a lubricating layer. Therefore, the base material and the layer containing the fluorine-containing resin are firmly adhered to each other, and excellent sliding performance is exhibited. In particular, when used in a refrigerant containing a fluorine-containing substance, it hardly wears even if there is no lubricating oil, and the sliding with a low friction coefficient can be maintained for a long time. Further, since the bearing (70) of the present embodiment exhibits excellent sliding performance by converting the inner surface of the base material to a predetermined surface roughness Ra by chemical conversion treatment, the sliding member can be easily and at low cost. Can be manufactured. Further, since the bearing (70) of the present embodiment can be manufactured by such a simple method, the sliding portion between the cylindrical portion (26) of the slide bush (25) and the protruding portion (53) of the movable scroll (50). Not limited to this, sliding members of various types and uses in a cylindrical shape can be manufactured by this method.

(Embodiment 2)
In the second embodiment, the protrusion (53) itself of the movable scroll (50) is a cylindrical bearing. That is, in FIG. 9, the inner surface (80) of the protrusion (53) is a sliding portion provided with a lubricant layer. Since the compressor (10) according to the present embodiment shown in FIG. 9 is the same as that of the first embodiment except for this sliding portion, the description of the same portions as those of the first embodiment is omitted.

  In the present embodiment, the projecting portion (53) inner surface (80) of the movable scroll (50) is roughened by chemical conversion treatment, and resin coating, firing, and inner peripheral processing are performed to form a sliding portion. Due to the chemical conversion treatment, the inner surface (80) has a surface roughness Ra of 1.2 μm. The applied resin is the same as that of the first embodiment, and the thickness of the resin layer is 70 μm.

  In addition to the function and effect of the first embodiment, the present embodiment does not require a press-fitting process into the housing and can further reduce the manufacturing cost.

(Other embodiments)
In Embodiments 1 and 2, the main shaft portion (21) is supported by the roller bearing (42) and the ball bearing (31) as a sliding portion, but the main shaft portion (21) may be supported by a journal bearing. In that case, a lubrication part in which a layer containing a fluorine-containing resin is formed on the surface of the base material surface of the bearing having a predetermined surface roughness Ra may be formed.

  In Embodiments 1 and 2, in the cylindrical bearing (70) of the scroll compressor (10), the substrate surface roughness Ra is set to a predetermined roughness, and a layer containing a fluorine-containing resin is formed on the surface. The compressor is not limited to the scroll type, and may be any type of compressor that compresses fluid. Further, the fluid is not limited to the refrigerant. Furthermore, the bearing of the present invention is not limited to the bearing used in the compressor. Any bearing such as a drive unit or a rotating part of a vehicle or a manufacturing apparatus may be used.

  In addition, a layer containing a fluorine-containing resin may be formed on the surface of the base member surface roughness Ra only on one member of the two members that slide on each other, and the base material may be formed on both members. The surface roughness Ra may be set to a predetermined roughness, and a layer containing a fluorine-containing resin may be formed on the surface.

  The base material of the bearing (70) is not limited to iron, and may be a metal other than iron such as aluminum.

  Further, the roughening of the substrate is not limited to the chemical conversion treatment, and various known methods such as a sandblast treatment can be used, and these methods may be combined. Moreover, the chemical | medical agent used for a chemical conversion treatment is not limited to manganese phosphate, Another phosphate and a well-known chemical | medical solution can be used.

  As described above, the bearing according to the present invention has excellent sliding performance, and the bearing manufacturing method according to the present invention can manufacture a bearing with excellent sliding performance at low cost. It is useful as an air conditioner, vehicle, manufacturing device, machine tool, etc.

1 is a cross-sectional view of a scroll compressor according to Embodiment 1. FIG. It is the schematic explaining a limit surface pressure test. It is a figure showing the relationship between surface roughness Ra of a base material, and limit PV. It is a figure which shows the result of the sliding test in a refrigerant | coolant. It is a figure which shows the result of the limit surface pressure test in the air. It is a figure which shows the result of the abrasion amount test in the air. It is a schematic process diagram of a conventional method for manufacturing a bearing. FIG. 3 is a schematic process diagram of the bearing manufacturing method according to the first embodiment. It is sectional drawing of the scroll compressor which concerns on Embodiment 2. FIG.

Explanation of symbols

70 Bearing 80 Bearing

Claims (11)

A cylindrical bearing (70),
A metal-made cylindrical base material, and a solid lubricating layer provided on the inner surface of the base material,
The inner surface of the base material has been subjected to a roughening treatment in which the arithmetic mean height Ra of the contour curve is a surface roughness greater than 0.5 μm and less than 10 μm,
The solid lubricating layer is a bearing (70) containing a fluorine-containing resin.   The bearing (70) of claim 1, wherein the bearing (70) is press-fitted into the housing.   The bearing according to claim 1 or 2, wherein the inner surface of the base material is subjected to a roughening treatment in which the arithmetic average height Ra of the contour curve is a surface roughness greater than 0.75 μm and less than 10 μm. 70).   The bearing (70) according to any one of claims 1 to 3, wherein the roughening treatment is a chemical conversion treatment.   The bearing (70) according to any one of claims 1 to 4, wherein the solid lubricating layer contains a polyamideimide resin. Forming a cylindrical base material made of metal;
A roughening step of roughening at least the inner surface of the substrate;
After the roughening step, forming a solid lubricating layer containing a fluorine-containing resin on the inner surface of the substrate;
A method for manufacturing a bearing (70), including:   7. The bearing according to claim 6, wherein in the roughening step, the arithmetic average height Ra of the contour curve is greater than 0.5 μm and less than 10 μm by roughening the inner surface of the base material. (70) The production method.   The bearing according to claim 6, wherein in the roughening step, the arithmetic average height Ra of the contour curve is greater than 0.75 μm and less than 10 μm by roughening the inner surface of the base material. (70) The production method.   The method for manufacturing a bearing (70) according to any one of claims 6 to 8, wherein in the roughening step, roughening is performed by chemical conversion treatment.   Furthermore, the manufacturing method of the bearing (70) as described in any one of Claim 6 to 9 including the press injection process which press-fits the said base material inside a housing. The method for manufacturing a bearing (70) according to claim 10, further comprising a step of polishing a surface of the solid lubricant layer before the press-fitting step.

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