Patent Application
20100086426
The present invention relates to a sliding member and a fluidic machine that uses the sliding member.
Fluororesin has excellent abrasion resistance and low friction characteristics, but the fluororesin by itself has poor strength, and it is therefore common to coat the fluororesin onto an iron base. On the other hand, it is difficult to assure that the fluororesin adheres strongly to the base. In view of this situation, various sliding members manufactured by using a porous sintered compact have conventionally been proposed because the anchor effect can be increased and considerable adhesion-improving effects can be expected when a porous sintered metal is used as a base.
The method for manufacturing a sintered sliding element of Patent Document 1 includes a step for sintering a porous molded article, a step for impregnating the resulting sintered compact with a resin, and a step for curing the resin.
The compressor sliding material of Patent Document 2 is manufactured by filling polytetrafluoroethylene (PTFE) or another fluororesin into the pores of a porous iron-based sintered alloy.
Japanese Laid-open Patent Application No. 64-11912
Japanese Laid-open Patent Application No. 10-88203
However, with the method for manufacturing a sintered sliding element of Patent Document 1, a suitable resin layer thickness is not formed in the combination of the porous sintered compact and the resin. Therefore, the adhesiveness between the resin and the base cannot be assured, the base is liable to pierce the resin layer and become exposed due to concavities and convexities on the base surface, and resistance to seizing is degraded.
Accordingly, a problem is presented in that it is difficult to reduce mechanical loss due to the smaller slider and to ensure the desired durability due to difficulties in achieving higher reliability.
The compressor sliding material of Patent Document 2 has a drawback in that the resin abrasion resistance is poor because only fluororesin is impregnated, adhesiveness between the resin and the base cannot be assured as in the case of Patent Document 1, and it is difficult to ensure the desired reliability.
An object of the present invention is to provide a sliding member having reduced mechanical loss due to a smaller slider and possessing high reliability due to improved durability, and to provide a fluidic machine that uses the sliding member.
A sliding member according a first aspect includes a porous sintered base and a resin composition. The porous sintered base is made of a porous sintered compact. The resin composition is coated onto the surface of the porous sintered base. The resin layer thickness is obtained by adding 10 μm or more to the pore depth. The resin layer thickness is the thickness of the resin composition. The pore depth is the depth of the pores exposed on the surface of the porous sintered base.
In this case, since the thickness of the resin layer is obtained by adding 10 μm or more to the pore depth, adhesiveness between the resin composition and the porous sintered base can be assured, and the porous sintered base is not exposed. Accordingly, mechanical loss due to a smaller slider is reduced and high reliability can be obtained from improved durability.
A sliding member according to a second aspect is the sliding member according to the first aspect, wherein the pore depth is 15 μm or more.
In this case, good adhesion can be obtained between the porous sintered base and the resin composition because the pore depth is 15 μm or more.
A sliding member according to a third aspect is the sliding member according to the first or second aspect, wherein the resin composition includes polyamidoimide and polytetrafluoroethylene.
In this case, excellent abrasion resistance and low friction characteristics can be obtained because the resin composition includes polyamidoimide and polytetrafluoroethylene.
A sliding member according to a fourth aspect is the sliding member according to any one of the first to third aspects, wherein the porosity, which is the volume ratio of the pores to the porous sintered base, is 10 to 30%.
In this case, an effect (anchor effect) for holding the resin composition to the surface of the porous sintered base can be sufficiently obtained while retaining the strength of the porous sintered base because the porosity, which is the volume ratio of the pores to the porous sintered base, is 10 to 30%.
A sliding member according to a fifth aspect is the sliding member according to any one of the first to fourth aspects, wherein the pores exposed on the surface of the porous sintered base are impregnated with the resin composition by vacuum suction. In this case, the thickness of the impregnation layer can be increased because the pores exposed on the surface of the porous sintered base are impregnated with the resin composition by vacuum suction.
A sliding member according to a sixth aspect is the sliding member according to any one of the first to fifth aspects, wherein the percentage content of oil contained in the porous sintered base is 5 wt % or less.
In this case, substantially no oil is contained inside the porous sintered base, and there is essentially no likelihood of defect (contamination) due to foreign matter because the percentage content of oil contained in the porous sintered base is 5 wt % or less.
A fluidic machine according to a seventh aspect is characterized in including the sliding member according to any of the first to sixth aspects.
In this case, mechanical loss due to a smaller slider in the fluidic machine is reduced and high reliability can be obtained from improved durability because the fluidic machine includes the sliding member according to any of the first to sixth aspects.
A fluidic machine according to an eighth aspect is the sliding member according to the seventh aspect, wherein the sliding member is a bearing.
In this case, adhesiveness between the resin composition and the porous sintered base in the bearing of the fluidic machine can be assured and the porous sintered base is not exposed because the sliding member is a bearing. Accordingly, mechanical loss due to a smaller slider is reduced and high reliability can be obtained from improved durability.
A fluidic machine according to a ninth aspect is the sliding member according to the eighth aspect, wherein the refrigerant used is carbon dioxide.
In this case, the refrigerant used is carbon dioxide, and because carbon dioxide has a high frictional load, the effect is particularly high, mechanical loss due to a smaller slider is reduced, and high reliability can be obtained from improved durability.
In accordance with the first aspect, adhesiveness between the resin composition and the porous sintered base can be assured, and the porous sintered base is not exposed. Accordingly, mechanical loss due to a smaller slider is reduced and high reliability can be obtained from improved durability.
In accordance with the second aspect, good adhesion can be obtained between the porous sintered base and the resin composition.
In accordance with the third aspect, excellent abrasion resistance and low friction characteristics can be obtained.
In accordance with the fourth aspect, an effect (anchor effect) for holding the resin composition to the surface of the porous sintered base can be sufficiently obtained while retaining the strength of the porous sintered base.
In accordance with the fifth aspect, the thickness of the impregnation layer can be increased.
In accordance with the sixth aspect, substantially no oil is contained inside the porous sintered base, and there is essentially no likelihood of defect (contamination) due to foreign matter.
In accordance with the seventh aspect, mechanical loss due to a smaller slider in the fluidic machine is reduced and high reliability can be obtained from improved durability.
In accordance with the eighth aspect, adhesiveness between the resin composition and the porous sintered base in the bearing of the fluidic machine can be assured and the porous sintered base is not exposed. Accordingly, mechanical loss due to a smaller slider is reduced and high reliability can be obtained from improved durability.
In accordance with the ninth aspect, with carbon dioxide, which has a high frictional load, the effect is particularly high, mechanical loss due to a smaller slider is reduced, and high reliability can be obtained from improved durability.
Embodiments of a sliding member according to the present invention will next be described with reference to the drawings.
A sliding member 1 shown in
The sliding member 1 is provided with a porous sintered base 2 made of a porous sintered compact, and a resin composition 3 coated onto the surface (see
The resin composition 3 has a resin-only layer 3a for covering the surface of the porous sintered base 2, and an impregnation layer 3b impregnated into the pores 6 that are exposed on the surface of the porous sintered base 2. The resin composition 3 is coated onto the surface of the porous sintered base 2 using a sprayer or a dispenser. In both coating methods, the filling ratio of the pores 6 is improved by vacuum suction from the opposite side of the resin-coated surface.
A resin layer thickness t1, which is the thickness of the resin composition 3, is a size obtained by adding 10 μm or more (preferably 20 μm or more) to a pore depth t2, which is the depth of the pores 6 exposed on the surface of the porous sintered base 2, as shown in
The difference Δd from the average surface height L due to the concavities and convexities on the coated surface 7 of the porous sintered base 2 is ±5 μm. Therefore, the resin layer thickness t1 must be t2+10 μm or more so that the porous sintered base 2 does not pierce the resin-only layer 3a and become exposed.
Good adhesiveness between the porous sintered base 2 and the resin composition 3 can be obtained because the pore depth t2 is 10 μm or more (preferably 20 μm or more). Adhesiveness cannot be assured when the thickness t2 of the impregnation layer 3b is less than 10 μm. On the other hand, when the pore depth t2 exceeds 100 μm, there is a drawback in that impregnation of the resin composition 3 becomes difficult.
Excellent abrasion resistance and low friction characteristics (i.e., slipping characteristics) can be obtained because the resin composition 3 includes polyamidoimide (PAI) and polytetrafluoroethylene (PTFE).
Specifically, the resin composition 3 includes PTFE or another fluororesin dispersed in PAI. The resin composition 3 furthermore includes calcium fluoride or the like in addition to PAI and PTFE.
The porosity, which is the volume ratio of the pores 6 to the porous sintered base 2, is 10 to 30%, and an anchor effect for holding the resin composition 3 to the surface of the porous sintered base 2 can be sufficiently obtained while retaining the strength of the porous sintered base 2.
The resin composition 3 is impregnated into the pores 6 exposed on the surface of the porous sintered base 2 by vacuum suction from the opposite side of the resin-coated surface. Vacuum suction is carried out during or after the application of the resin composition 3. Vacuum suction is carried out by forming a negative pressure on the back surface of the porous sintered base 2 and causing the resin composition 3 to be impregnated from the surface of the porous sintered base 2, whereby the thickness of the impregnation layer 3b can be increased.
The percentage content of oil contained in the porous sintered base 2 is 5 wt % or less. Therefore, substantially no oil is contained inside the porous sintered base 2, and there is essentially no likelihood of defect (contamination) due to foreign matter.
The sliding member 1 is used as a slider of a scroll-type high-low pressure dome type compressor 101 described below.
The high-low pressure dome type compressor 101 according to the first embodiment constitutes a refrigerant circuit together with an evaporator, a condenser, an expansion mechanism, and the like; acts to compress a gas refrigerant in the refrigerant circuit; and is primarily composed of a longitudinally cylindrical hermitically sealed dome type casing 10, a scroll compression mechanism 15, an Oldham ring 39, a drive motor 16, a lower main bearing 60, a suction tube 19, and a discharge tube 20.
The sliding member 1 of the first embodiment can be applied to at least one component among a pin bearing part 26c of a movable scroll 26, a bearing 34 of an upper housing 23, and a bearing part 60a of a lower main bearing 60. The sliding member 1 can be applied to a pin bearing (internal periphery of the piston), a main bearing (front head), a secondary bearing (rear head), and other components when application is made to a swing compressor or the like.
The constituent elements of the high-low pressure dome type compressor 101 will be described in detail below.
(1) Casing
The casing 10 has a substantially cylindrical trunk casing 11, a saucer-shaped upper wall portion 12 welded in an airtight manner to an upper end of the trunk casing 11, and a saucer-shaped lower wall portion 13 welded in an airtight manner to a lower end of the trunk casing 11. Primarily accommodated in the casing 10 are the scroll compression mechanism 15 for compressing gas refrigerant, and the drive motor 16 disposed below the scroll compression mechanism 15. The scroll compression mechanism 15 and the drive motor 16 are connected by a drive shaft 17 disposed so as to extend in the vertical direction inside the casing 10. As a result, a clearance space 18 is formed between the scroll compression mechanism 15 and the drive motor 16.
(2) Scroll Compression Mechanism
The scroll compression mechanism 15 is primarily composed of a housing 23, a fixed scroll 24 provided in close contact above the housing 23, and the movable scroll 26 for meshing with the fixed scroll 24, as shown in
a) Housing
The housing 23 is press-fitted and secured to the trunk casing 11 across the entire external peripheral surface of the housing in the peripheral direction. In other words, the trunk casing 11 and the housing 23 are in kept close contact in an airtight manner across the entire periphery. For this reason, the interior of the casing 10 is partitioned into a high-pressure space 28 below the housing 23, and a low-pressure space 29 above the housing 23. Also, the fixed scroll 24 is fastened and secured by a bolt 38 to the housing 23 so that the upper end surface is in close contact with the lower end surface of the fixed scroll 24. A housing concavity 31 concavely disposed in the center of the upper surface, and a bearing portion 32 that extends downward from the center of the lower surface, are formed in the housing 23. A bearing hole 33 that passes through in the vertical direction is formed in the bearing portion 32, and a drive shaft 17 is rotatably fitted to the bearing hole 33 via the a shaft bearing 34.
b) Fixed Scroll
The fixed scroll 24 is primarily composed of an end plate 24a and a spiral (involute shape) wrap 24b formed on the lower surface of the end plate 24a. A discharge channel 41 that is in communication with a compression chamber 40 (described later), and an enlarged concave portion 42 that is in communication with the discharge channel 41, are formed in the end plate 24a. The discharge channel 41 is formed so as to extend in the vertical direction in the center portion of the end plate 24a. The enlarged concave portion 42 is composed of a concave portion that is concavely provided to the upper surface of the end plate 24a and widens in the horizontal direction. A lid body 44 is fastened and secured using a bolt 44a to the upper surface of the fixed scroll 24 so as to cover the enlarged concave portion 42. A muffler space 45 composed of an expansion chamber for muffling the operation noise of the scroll compression mechanism 15 is formed by covering the enlarged concave portion 42 with the lid body 44. The fixed scroll 24 and the lid body 44 are sealed by close contact via packing, which is not depicted.
c) Movable Scroll
The movable scroll 26 is primarily composed of an end plate 26a, a spiral (involute shape) wrap 26b formed on the upper surface of the end plate 26a, a bearing portion 26c formed on the lower surface of the end plate 26a, and a groove portion 26d formed in the both ends of the end plate 26a, as shown in
d) Other
A communication channel 46 is formed in the scroll compression mechanism 15 across the fixed scroll 24 and the housing 23. The communication channel 46 is formed so that a scroll-side channel 47, notched and formed in the fixed scroll 24, and a housing-side channel 48, notched and formed in the housing 23, are in communication with each other. The upper end of the communication channel 46, i.e., the upper end of the scroll-side channel 47, opens to the enlarged concave portion 42, and the lower end of the communication channel 46, i.e., the lower end of the housing-side channel 48, opens to the lower end surface of the housing 23. In other words, a discharge port 49 through which the refrigerant of the communication channel 46 flows out to the clearance space 18 is constituted by the lower end opening of the housing-side channel 48.
(3) Oldham Ring
An Oldham ring 39 is a member for preventing the movable scroll from rotating, as described above, and is fitted into an Oldham groove (not shown) formed in the housing 23. The Oldham groove is an elliptical groove disposed in a position that faces the housing 23.
(4) Drive motor
The drive motor 16 is a DC motor in the present embodiment, and is primarily composed of an annular stator 51 secured to the inner wall surface of the casing 10, and a rotor 52 rotatably accommodated with a small gap (air gap channel) inside the stator 51. The drive motor 16 is disposed so that the upper end of a coil end 53 formed at the upper end of the stator 51 is at substantially the same height position as the lower end of the bearing portion 32 of the housing 23.
A copper wire is wrapped around the teeth portion of the stator 51, and coil ends 53 are formed above and below the stator. The external peripheral surface of the stator 51 is provided with core-cut portions that have been notched and formed in a plurality of locations from the upper end surface to the lower end surface of the stator 51 at prescribed intervals in the peripheral direction. A motor cooling channel 55 that extends in the vertical direction is formed by the core-cut portions between the trunk casing 11 and the stator 51.
A rotor 52 is drivably connected to the movable scroll 26 of the scroll compression mechanism 15 via the drive shaft 17 disposed in the axial center of the trunk casing 11 so as to extend in the vertical direction. A guide plate 58 for guiding the refrigerant that has flowed out of the discharge port 49 of the communication channel 46 to the motor cooling channel 55 is disposed in the clearance space 18.
(5) Lower Main Bearing
The lower main bearing 60 is disposed in a lower space below the drive motor 16. The lower main bearing 60 is secured to the trunk casing 11, constitutes the lower end-side bearing of the drive shaft 17, and supports the drive shaft 17 in the bearing part 60a of the lower main bearing 60.
(6) Suction Tube
The suction tube 19 is used for guiding the refrigerant of the refrigerant circuit to the scroll compression mechanism 15, and is fitted in an airtight manner into the upper wall portion 12 of the casing 10. The suction tube 19 passes through the low-pressure space 29 in the vertical direction, and the inside end portion is fitted into the fixed scroll 24.
(7) Discharge Tube
The discharge tube 20 is used for discharging the refrigerant inside the casing 10 to the exterior of the casing 10, and is fitted in an airtight manner into the trunk casing 11 of the casing 10. The discharge tube 20 has an inside end portion 36 formed in the shape of a cylinder extending in the vertical direction and secured to the lower end portion of the housing 23. The inside end opening of the discharge tube 20, i.e., the inlet, is opened downward.
The following test methods were used to obtain the test results showing the correlation between the load limit and the resin layer thickness/pore depth (
Sintered base:
Coating material: resin composition
Based on the weight ratio, for a PAI weight ratio of 50 to 60%: a PTFE ratio of 20 to 30%, a calcium fluoride ratio of 10 to 20%, and an alumina ratio of 1 to 5%
Coating method:
Baking conditions
Baking was carried out at 200 to 300° C. for about 30 to 60 minutes.
Disk machining: Lapping cl Evaluation
TP shape
Conditions: Dry atmosphere, PV
As shown in the graph of
The tested sample had a portion of the resin peeled away, and adhesive strength could be evaluated in relative terms using the seizing load limit.
Correlation between the load limit and the resin layer thickness/pore depth (
Among the test results (TABLES 1 and 2;
It is apparent from the graph in
It is apparent from the graph in
In the sliding member 1 of the first embodiment, the resin layer thickness t1 of the resin composition 3 is a thickness obtained by adding 10 μm or more (preferably 20 μm or more) to the pore depth t2 of the pores 6. Therefore, adhesiveness between the porous sintered base 2 and the resin composition 3 can be assured and the porous sintered base 2 is not exposed. Accordingly, the mechanical loss due to a smaller slider is reduced and high reliability can be obtained from improved durability.
In the sliding member 1 of the first embodiment, good adhesiveness between the porous sintered base 2 and the resin composition 3 can be obtained because the pore depth t2 is 15 μm or more (preferably 20 μm or more).
In the sliding member 1 of the first embodiment, excellent abrasion resistance and low friction characteristics can be obtained because the resin composition 3 includes polyamidoimide (PAI) and polytetrafluoroethylene (PTFE).
In the sliding member 1 of the first embodiment, the porosity, which is the volume ratio of pores 6 to the porous sintered base 2, is 10 to 30%. Therefore, an anchor effect for holding the resin composition 3 to the surface of the porous sintered base 2 can be sufficiently obtained while retaining the strength of the porous sintered base 2.
In the sliding member 1 of the first embodiment, the impregnation layer 3b can be made thicker because the resin composition 3 is impregnated by vacuum suction into the pores 6 exposed on the surface of the porous sintered base 2.
In the sliding member 1 of the first embodiment, the percentage content of oil contained in the porous sintered base 2 is 5 wt % or less. Therefore, substantially no oil is contained inside the porous sintered base 2, and there is essentially no likelihood of defect (contamination) due to foreign matter.
In the first embodiment, the high-low pressure dome type compressor 101, which is a fluidic machine, is provided with the sliding member 1. Therefore, mechanical loss due to a smaller slider in a fluidic machine is reduced, and high reliability from improved durability can be obtained.
In the first embodiment, the sliding member 1 is used as a bearing of the high-low pressure dome type compressor 101. Therefore, adhesiveness between the resin composition and the porous sintered base in the bearing can be assured and the porous sintered base is not exposed. Accordingly, the mechanical loss due to a smaller slider is reduced and high reliability can be obtained from improved durability.
The refrigerant used in the compressor, which is a fluidic machine, may be carbon dioxide. With carbon dioxide, which has a high frictional load, the effect is particularly high, mechanical loss due to a smaller slider is reduced, and high reliability can be obtained from improved durability.
A sliding member 71 of a second embodiment is different from the sliding member 1 of the first embodiment in that an oxide film 78 is formed on the surface of a porous sintered base 72 in order to prevent rusting and oil leakage, but the configuration is otherwise the same. The sliding member 71 on which the oxide film 78 has been formed will be described below.
The sliding member 71 shown in
The sliding member 71 is provided with the porous sintered base 72 composed of a porous sintered compact; an oxide film 78 formed by oxidizing the surface of the porous sintered base 72 (see
The oxide film 78 is formed by treating the porous sintered base 72 with steam. Specifically, the oxide film 78 composed of a black Fe3O4 having a predetermined thickness (about several microns) is formed to a uniform thickness by being heated to a predetermined temperature range (e.g., 500 to 560° C.) in a water vapor-atmosphere oven. The oxide film 78 is formed to a uniform thickness on the inner surface of the pores 76 exposed on the surface of the porous sintered base 72, as shown in
The resin composition 73 has a resin-only layer 73a for covering the surface (specifically, the surface of the porous sintered base 72 covered by the oxide film 78) of the porous sintered base 72, and an impregnation layer 73b impregnated inside the pores 76 of the porous sintered base 72. The resin composition 73 is coated onto the oxide film 78 on the surface of the porous sintered base 72 using a spray or a dispenser.
Excellent abrasion resistance and low friction characteristics (i.e., slipping characteristics) can be obtained because the resin composition 73 includes polyamidoimide (PAI) and polytetrafluoroethylene (PTFE). Specifically, the resin composition 73 includes PTFE or another fluororesin dispersed in PAI. The resin composition 73 furthermore includes calcium fluoride or the like in addition to PAI and PTFE.
As in the case of the resin composition 3 of the first embodiment, the resin layer thickness t1, which is the thickness of the resin composition 73, is preferably a thickness obtained by adding 10 μm or more (preferably 20 μm or more) to the pore depth t2, which is the depth of the pores 76 exposed on the surface of the porous sintered base 72, as shown in
Good adhesiveness between the porous sintered base 72 and the resin composition 73 can be obtained because the pore depth t2 is 10 μm or more (preferably 20 gm or more). Adhesiveness cannot be assured when the pore depth t2 of the impregnation layer 73b is less than 10 μm. On the other hand, when the pore depth t2 exceeds 100 μm, there is a drawback in that impregnation of the resin composition 73 becomes difficult.
The porosity, which is the volume ratio of pores 76 to porous sintered base 72, is 10 to 30%, and an anchor effect for holding the resin composition 73 to the surface of the porous sintered base 72 can be sufficiently obtained while retaining the strength of the porous sintered base 72.
The resin composition 73 is impregnated into the pores 76 exposed on the surface of the porous sintered base 72.
The sliding member 71 is also used as a slider of the scroll-type high-low pressure dome type compressor 101 described above as in the case of the sliding member 1 of the first embodiment.
In the second embodiment, a quantitative crosscut test was carried out in the manner described below in order to accurately measure the adhesive strength of the resin composition 73 formed on the surface of the porous sintered base 72 of the sliding member 71.
Conventionally, in order to measure the adhesive strength of a resin layer formed on the surface of a metal base, the adhesive strength of a resin coating is evaluated by cutting notches at equal intervals in the resin coating, attaching adhesive tape to the notched portion, and thereafter peeling the tape away to determine the spacing of the notched portion at the limit at which the resin coating is peeled away. However, it is difficult to quantitatively evaluate adhesive strength using such an evaluation method. There is also a problem in that adhesion with the tape is degraded in the case of a fluororesin or another resin layer that has poor wettability. A test of adhesive strength by the peeling tape method cannot be carried out with good reproducibility when the resin layer is not formed on a flat plate, e.g., in the case of a cylindrical internal peripheral surface or the like.
In view of the above, tape peeling is not used in the second embodiment, but rather an adhesive strength test method is used that can accurately evaluate the adhesive strength of a resin layer for a fluororesin layer or a curved resin layer.
Specifically, notches T1 that extend in the horizontal direction are formed in longitudinal alignment at equal intervals on the surface of the resin composition 73, and notches T21 to T26 that extend in the longitudinal direction are formed in horizontal alignment at different intervals, as shown in
Consequently, notches are made in the form of a matrix having variable horizontal widths (W21 to W25; e.g., variable from 2.0 mm to 0.2 mm in increments of 0.2 mm) in the surface of the resin composition 73, as shown in
In the method for testing adhesive strength, the portions (so-called islands) enclosed by the grid squares formed by notching are preferably rectangular, but the test can also be carried out using a rhombic shape.
Also, in the method for testing adhesive strength, the surface of the resin composition 73 is not limited to a flat plate, and it is also possible to make an evaluation using an arcuate shape or a concavo-convex shape.
For example, when the adhesive strength of the resin coating formed on the inside periphery of the cylindrical base is measured using the method for testing adhesive strength, first, (i) rectilinear notches are made in an aligned fashion at equal intervals about the cylindrical internal periphery along the axial direction of the cylinder on the internal peripheral surface of the cylinder. Next, (ii) circular notches are made in an aligned fashion in the axial direction at different intervals along the circumferential direction of the cylinder in the internal peripheral surface of the cylinder. Next, (iii) the adhesive strength is found by observation using a microscope or the like to determine the interval at which natural peeling of the resin coating occurs (i.e., peel width).
Here, spiral notches may be used instead of circular notches formed in the circumferential direction. In such a case, the interval between adjacent notches differs and the peel width can be measured by gradually reducing the pitch of the spiral.
The quantitative crosscut test is described in greater detail below.
1. Method for fabricating samples
Three samples Nos. 1 to 3 that correspond to the comparative examples 1 and 2 and the example of the present invention were fabricated, and each of the samples was subjected to the quantitative crosscut test, as shown in TABLE 3. Sample Nos. 1 to 3 are described in detail below.
Sample No. 1: S45C+manganese phosphate treatment
A coating was applied to the internal periphery of a base obtained by performing a manganese phosphate film treatment on an S45C cylinder, which was then baked.
Sample No. 2: Sintered base (without steam treatment)
The sintered base (JPMA SMF 4040) was sintered, after which no steam treatment was carried out. A coating was applied to the internal periphery of the base as in the case of sample No. 1, after which the base was baked.
Sample No. 3: Sintered base (with steam treatment)
The sintered base (JPMA SMF 4040) was sintered and then treated with steam. A coating was applied to the internal periphery of the base as in the case of sample No. 1, after which the base was baked.
JPMA SMF 4040 as used herein is an iron-copper-based metal powder stipulated in the Japanese Powder Metallurgy Association Specification.
The steam treatment in the present test is a treatment for obtaining a black Fe3O4 film by heating the material to 500 to 560° C. in a water vapor-atmosphere oven.
2. Shape of the sample for quantitative crosscut test
Shape of the sintered base
OD Φ4.4 (outside diameter: mm), ID Φ34.0 (inside diameter: mm), H29
Coating and machining
The inside diameter of the base was coated by dispenser coating. A base having a thickness of 100 to 150 μm at the time of sintering was brought to a thickness of 40 to 60 μm at the time of testing by inside-diameter cutting.
Machining for the quantitative crosscut test
The samples were divided into two or four pieces in order to make notches in the internal periphery of the cylindrical sample.
3. The method for carrying out the quantitative crosscut test is described in detail below in the section titled <Method for carrying out the quantitative crosscut test>.
4. Results of quantitative crosscut test
The results of the quantitative crosscut test are as shown in TABLE 3.
The following is apparent from the test results of TABLE 3.
Adhesion can be increased using manganese phosphate when a sintered base is used (the anchor effect can be increased when a sintered base is used).
Adhesion can be improved using a steam treatment (sample No. 3) in comparison with the case in which the steam treatment is not performed (sample No. 2).
Based on the above, in the example of the present invention (for sample No. 3), it is apparent that an effect of improved adhesion can be obtained by using steam treatment after sintering.
1. Apparatus
A notching tool having a blade edge of good quality is required.
2. Guide
A guide having an equidistant spacer may be used when a single notching tool is used for making notches at equal intervals.
3. Adhesive tape
Adhesive tape (an adhesive strength of 10±1 N per 25 mm of width) may be used when a film that has lost its adhesive strength is removed.
4. Observation device
An optical microscope having a magnification of about 100 to 300 times is used.
5. Test piece
The shape of the test pieces is not particularly specified. However, the test is preferably carried out in three different locations that are 5 mm or more away from the edge of the test plate.
The film thickness is preferably uniform among the test pieces.
6. Procedure
6.1 Test conditions and number of tests
6.2 Curing of the test pieces
6.3 Cutting interval and number of cuts
6.4 Notching and removal of the film by manual procedure
6.5 Notching the film using an electric tool
7. Describing the results
The evaluation of the test results can be made immediately following removal of a film that has lost its adhesive strength.
The peeled film is observed from above using an observation device.
The interval of the peeled film and the interval of the film that has not peeled are quantified. The test results are obtained using two numerical values as required.
Adhesiveness is higher as the interval of the peeled portions decreases.
In the second embodiment, it is possible to block the small pores of the porous sintered base 72 and to prevent a reduction in the surface activity of the porous sintered base 72 because an oxide film 78 is formed on the surface of the porous sintered base 72. The occurrence of red rust (Fe2O3) on the surface of the porous sintered base 72 can be prevented by forming the oxide film 78 composed of black Fe3O4. A reduction in the adhesiveness of the resin composition 73 can thereby be controlled, and productivity of the sliding member 71 can be improved.
In the second embodiment, the small pores on the surface of the porous sintered base 72 are blocked, and machine oil or solid lubricant impregnated in the porous sintered base 72 can be prevented from seeping out to the boundary between the porous sintered base 72 and the resin composition 73 because the oxide film 78 is formed on the surface of the porous sintered base 72. A reduction in the adhesiveness of the resin composition 73 can be controlled to the same degree as in the case in which a porous sintered base not impregnated with oil is used, and the productivity of the sliding member 71 can be improved.
Also, a reduction in the adhesiveness of the resin composition 73 can be similarly controlled even in the case of porous sintered bases 72 having differing porosities.
In the second embodiment, the oxide film 78 having a predetermined thickness can be formed to a uniform thickness because the oxide film 78 is formed by treating the porous sintered base 72 with steam.
The present invention can be applied to all varieties of sliding members as long as the sliding member has a porous sintered base and a resin composition coated onto the surface of the porous sintered base. The sliding member of the present invention is used in bearings and various other sliders. In particular, the sliding member of the present invention is preferably used as a bearing or the like of a CO2 compressor operated under high temperature and high pressure. The sliding member can also be adopted as a bearing of other compressors.
The present invention can also be used both when the porous sintered base is impregnated with oil and when the preform is not impregnated with oil.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-264341 | Sep 2006 | JP | national |
| 2007-250533 | Sep 2007 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2007/068885 | 9/27/2007 | WO | 00 | 3/17/2009 |
