JP2003202024A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long life rolling bearing which suppresses the lowering of the holding function of a rolling element even when water content invades into the bearing. <P>SOLUTION: In this rolling bearing, a plurality of rolling elements are rotatably held between an outer ring and an inner ring through a cage, and grease is sealed by a seal device for closing an opening at the end part of a portion where the rolling elements are installed. The cage is a formed body of resin composition having a water absorption obtained when the cage is immersed in water at 23°C for 24 hours is 1.5 wt.% or below. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling device suitable for use in an environment where water or steam is applied, such as a steam supply device or a washing device for a fuel cell. It relates to improvement of bearings. 2. Description of the Related Art A fuel cell which is considered to be mounted on an automobile or the like basically has an electrolyte sandwiched between a fuel electrode and an air electrode.
It is configured by connecting two electrodes with a conductor. For power generation, hydrogen is supplied to the fuel electrode and oxygen (air) is supplied to the air electrode.
When hydrogen is supplied to the fuel electrode, the hydrogen reacts with a catalyst (platinum, ruthenium, etc.) supported on the electrolyte and is decomposed into protons and electrons. The protons then reach the cathode through the electrolyte, which generates heat. Since the electrolyte allows protons to pass but does not allow electrons, the electrons travel through an external conductor to reach the cathode. At this time, current flows through the conductor. At the air electrode, protons and electrons are recombined, returning to the original hydrogen. At that time, oxygen supplied to the air electrode is combined with hydrogen to form water. Again, heat is generated. [0003] Hydrogen used for fuel must be artificially produced unlike oxygen in the air. There is also a method of directly supplying hydrogen by mounting a hydrogen tank together with the fuel cell, but there is a problem with efficiency and safety.Generally, another fuel containing hydrogen such as methanol or gasoline is loaded and reformed. They are reformed by adding high-temperature steam in a vessel, and used as hydrogen. In the case of a solid polymer membrane fuel cell, which has become mainstream in recent years, it is necessary to wet the solid polymer membrane and increase the ionic conductivity of the membrane. For that, fuel gas (hydrogen)
And humidifying the oxidant gas (air or the like) to supply moisture to the solid polymer film. [0004] As described above, it is generally necessary to feed steam around the fuel cell, and a pressure feeding device (compressor) is used to increase the efficiency of feeding steam. FIG. 3 shows an impeller-type water vapor pumping apparatus as an example of the pumping apparatus. In this pumping apparatus, an impeller 52 is attached to a rotating shaft 51, and the rotating shaft 51 is supported by rolling bearings 53a and 53b. The impeller 52 rotates at a high speed with the high speed rotation of the rotating shaft 51, and the steam sucked from the steam suction port 54 is pressurized by the centrifugal force of the impeller 52, and the pressurization formed by the housing 55 and the back plate 56. The water is pumped from the steam outlet 58 through the volute 57. On the other hand, as rolling bearings 53a and 53b,
Conventionally, a rolling bearing as shown in FIG. 1 has been used.
In this rolling bearing, a plurality of rolling elements (balls) 3 are held at substantially equal intervals along a circumferential direction by a retainer 4 between an outer ring 1 and an inner ring 2, and one end surface or both end surfaces of the bearing are made of rubber. Alternatively, a sealing device 5 made of plastic or the like is mounted. The sealing device 5 is mounted on the bearing end face by fitting a mounting fitting portion 6 provided on one end thereof into a fitting groove 7 provided on the outer ring 1, and is mounted on the other end. The end 8 is provided with a lip 10 that comes into contact with a seal groove 9 provided in the inner ring 2 in order to improve the sealing performance. However, in this rolling bearing, the lip portion 10 of the seal device 5 wears over time due to sliding contact with the seal groove 9 to form a gap between the lip portion 10 and the seal groove 9, and moisture or the like enters from the outside. It will be easier. The pressure feeding device shown in FIG. 3 employs a configuration in which a baffle 62 and a bush 63 are attached to the rotating shaft 51 to prevent water vapor from entering the rolling bearings 53a and 53b, but the sealing property of the sealing member 59 is also improved. Since it decreases with time, there is a limit in preventing the intrusion of water vapor. For this reason, in the rolling bearings 53a and 53b, a resin-made retainer is sometimes used in order to suppress rust caused by invading water, and a molded product of polyamide 46 or polyamide 66 is generally used (for example, , Patent Documents 1 and 2). However, these resins have high water absorption and swell due to infiltration water, so that the function of holding the rolling elements is reduced, which has an adverse effect on the durability life. [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-130441 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-106572 The present invention has been made in view of the above situation. It is another object of the present invention to provide a long-life rolling bearing in which the function of holding a rolling element is less reduced even when moisture enters the inside of the bearing. [0009] In order to achieve the above object, the present invention provides a method for holding a plurality of rolling elements rotatably between an outer ring and an inner ring via a retainer, and In a rolling bearing in which grease is sealed by a sealing device that seals an end opening of a portion where a rolling element is installed, the retainer may be configured as follows:
A rolling bearing characterized by being a molded article of a resin composition having a water absorption of 1.5% by weight or less when immersed in water at 24 ° C. for 24 hours. [0010] In the rolling bearing of the present invention, the retainer is made of a resin composition that is less swelled by moisture, so that even if moisture enters the inside of the bearing, the retaining function is not deteriorated, and a long life is obtained. Become. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a rolling bearing according to the present invention will be described in detail. The rolling bearing of the present invention is not particularly limited in structure except for a cage made of a specific resin composition described in detail below. For example, the rolling bearing having the structure shown in FIG. Examples can be given. Further, the shape of the retainer may be a crown type retainer 4 as shown in FIG. The illustrated crown-shaped retainer 4 has substantially semicircular pockets 42 formed at a plurality of locations in the circumferential direction of a base 41, and each pocket 42 holds a ball (not shown) by a pair of elastic pieces 43. Configuration. As a base resin for forming the retainer 4,
A synthetic resin having a water absorption (after immersion in water at 23 ° C. for 24 hours) of 0.3% by weight or less according to the test method specified in ASTM D-570 is preferable. Table 1 below shows the water absorption of a typical synthetic resin. The water absorption of polyphenylene sulfide (PP
S), polybutylene terephthalate (PBT), polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PF)
A), tetrafluoroethylene-ethylene copolymer (E
TFE), polyetheretherketone (PEEK),
Polyimide (crystallinity: PI), polyamide 12 (PA1
2) Polyamide 612 (PA612) is preferable. [Table 1] [0015] As shown in Table 1, polyamide 66 (PA66), which is conventionally most frequently used as a cage material, is used.
Polyamide 46 (PA46) has a large water absorption of 1.3% by weight and 2.4% by weight, respectively, and is not suitable in the present invention. However, these polyamide resins are considered to be useful as base resins because of their unique properties of increasing mechanical strength by water absorption.
Therefore, by filling a reinforcing agent such as a glass fiber with a high amount to suppress water absorption, it is possible to apply the present invention to use in a place where water infiltration is small. The filling amount is such that the water absorption when immersed in water at 23 ° C. for 24 hours is 1.5% by weight or less, preferably 1% by weight or less, as defined in the present invention. However, as the filling amount increases, the decrease in the water absorption rate also increases, but at the same time, the viscosity at the time of melting increases and the moldability deteriorates. Specifically, the glass fiber (GF) -filled polyamide composition shown in Table 2 below can be exemplified. [Table 2] Filling with a reinforcing agent such as glass fiber
It is also effective for the synthetic resin having a water absorption of 0.3% by weight or less specified in ASTM D-570 described above. By filling, the water absorption can be reduced and the mechanical strength can be enhanced. The filling amount is such that the water absorption when immersed in water at 23 ° C. for 24 hours is 1.5% by weight, preferably 1% by weight or less. However, considering formability,
It is preferable that the upper limit of the filling amount is 40% by weight. On the other hand, when the lower limit of the filling amount is less than 5% by weight, the enhancement of the mechanical strength is small, and the practicality is lowered. As a reinforcing agent other than glass fiber, carbon fiber (CF), potassium titanate whisker, aluminum borate whisker and the like can be suitably used. A resin composition that satisfies the water absorption of the present invention and has the above-mentioned base resin containing reinforcing fibers can also be obtained from the market. For example, “KF Polymer T-L” manufactured by Kureha Chemical Industry Co., Ltd. # 850CF ”(PVDF containing 15% by weight of CF),“ Fortron KPS1140A1 ”(PP containing GF of 40% by weight) manufactured by Polyplastics Co., Ltd.
S), "VICTREX450C" manufactured by Sumitomo Chemical Co., Ltd.
A30 "(PEEK containing 30% by weight of CF)," Aurum JCN3030 "manufactured by Mitsui Chemicals, Inc. (30% by weight of CF)
PI), “Aflon COP CF-” manufactured by Asahi Glass Co., Ltd.
5020-2 "(ETFE containing 20% by weight of CF)," Zytel 70G-33HR-L "(manufactured by DuPont) (hydrolysis-resistant and stabilized, PA66 containing 33% by weight of GF),
"Stanyl TS" manufactured by DSM JSR Engineering Plastics Co., Ltd.
200F6 "(PA46 containing 30% by weight of GF). In addition to the reinforcing fiber material, various additives conventionally compounded in a synthetic resin cage, such as a filler other than the fiber material, an antioxidant, an antioxidant, are added to the base resin. And a flame retardant and the like can be appropriately added. Further, special treatment such as hydrolysis suppression by hot water may be performed. As a method of molding into a cage, an injection molding method is preferable because of its excellent productivity, and a resin composition obtained by uniformly kneading the above-mentioned base resin, reinforcing fiber material and additives, or the above-mentioned commercially available method. The article may be filled into, for example, an in-line screw type injection molding machine and molded into, for example, a crown-shaped retainer 4 shown in FIG. The above-mentioned cage 4 is incorporated in a rolling bearing, and this rolling bearing is used as rolling bearings 53a and 53b of an impeller type steam pumping device as shown in FIG. The rolling bearing according to the present invention may be any of various steam pumping devices such as a scroll type, a swash plate type, a waffle type, a vane type and a screw type, or a washing device, in addition to an impeller type steam pumping device. , And exhibit excellent durability in any device. Although there is no limitation on the structure of each steam pumping device and the washing device, an example in which the rolling bearing of the present invention is incorporated in a scroll steam pumping device, a swash plate steam pumping device and a screw steam pumping device will be described below. FIG. 4 is a side sectional view showing an embodiment in which the rolling bearing of the present invention is applied to a scroll compressor device. The illustrated scroll compressor device 10
Reference numeral 0 denotes a compression mechanism unit 110 including a fixed scroll 111 and an orbiting scroll 112, and a crank mechanism unit 130 for orbiting the orbiting scroll 112 by a crank pin 122a provided eccentrically with respect to the motor main shaft 122.
And a drive motor unit 120 for rotating the motor spindle 122
Consists of The crank mechanism 130 is provided with a rotation preventing mechanism 132 for preventing the orbiting scroll 112 from rotating. The anti-rotation mechanism 132 includes an Oldham coupling, a pin & ring coupling, and the like in addition to the ball coupling 134 shown in FIG. In addition, the anti-rotation mechanism 1
As No. 32, a crank mechanism using a rolling bearing as disclosed in JP-A-2002-70762 is known. In the scroll compressor device 100 according to the present invention, any of the above-described rotation preventing mechanisms may be employed. The fixed scroll 111 includes a fixed base 111a formed in a disk shape, a spiral swirling part 111c standing upright from the fixed base 111a, and an outer peripheral wall 111b covering the swirling spiral part 111c. The orbiting scroll 112 includes a disc-shaped orbiting base 112b and a spiral orbiting spiral part 112a standing upright from the orbiting base 112b.
Consists of At the center on the rear side of the swivel base 112b, there is provided a bottomed cylindrical concave portion 112c. Fixed base 11
At a substantially vertical center in FIG. 5 in FIG. 5A, a discharge port 114 for air or the like compressed between the fixed scroll 111 and the orbiting scroll 112 is provided. The needle roller bearing 133 is inserted on the inner peripheral side of the concave portion 112c using the concave portion 112c as a housing. The needle roller bearing 133 uses the crank pin 122a of the motor main shaft 122 as a rotation axis, and the orbiting scroll 1
12 is rotatably supported. In the drive motor section 120, the drive motor 121 is a rotor 1 fitted to the motor main shaft 122.
23 and the coil 12 provided on the outer peripheral side of the rotor 123.
4 is provided inside the motor housing 101. The motor main shaft 122 is connected to the motor housing 1.
01, is rotatably supported via the rolling bearing 102 of the present invention, and the end on the rear side (right side in FIG. 4) is also rotatably supported on the rear housing 104 via the rolling bearing 103 of the present invention. Have been. Further, the motor main shaft 122 is connected to the rolling bearing 102 by a crank pin 122a.
Side, the seal 1 between the motor housing 101
06 is interposed, and the rear side (the right end side in FIG. 4)
, The seal 107 between the rear housing 104
Is interposed. Further, the motor main shaft 122 is provided with a balance weight 122b, and the balance weight 122b cancels the moment of inertia generated when the orbiting scroll 112 turns, thereby reducing vibration. In the scroll compressor device 100 having the above-described configuration, when power is supplied to the drive motor 121, the motor main shaft 122 rotates, and the rotation is transmitted via the drive crank mechanism 130 to the orbiting scroll 112.
Is transmitted to. The orbiting scroll 112 includes the motor spindle 1
With the rotation of the fixed scroll 111, the fixed scroll 111 is turned while engaging with the fixed scroll 111, and the fixed scroll 11
Air is sucked in between the fixed scroll 111 and compressed air. Thereafter, compressed air or the like is discharged from the discharge port 114 to the electrode side of the fuel cell. FIG. 5 shows a known scroll-type steam pumping apparatus. In the illustrated scroll compressor device 140, the crank mechanism unit 150 includes a drive crank mechanism 151 that causes the orbiting scroll 112 to perform a orbiting motion, and the orbiting scroll 11.
2 is configured by a driven crank mechanism 152 for preventing the rotation of the second crank. The driven crank mechanism 152 has a concave holding portion 112 c provided on the orbiting scroll 112, and two rows of radial balls that make the crankpin 153 a of the driven crankshaft 153 and the crankpin 153 a rotatable with respect to the orbiting scroll 112. And a bearing 154. The driven crankshaft 153 is rotatably supported on the motor housing 101 via a double-row ball bearing 155 on the side opposite to the crankpin 153a. The driven crankshaft 153 is provided with a balance weight 153b in the same manner as the motor main shaft 122. The balance weight 153b cancels the moment of inertia generated when the orbiting scroll 112 turns, thereby reducing vibration. Have been. Other configurations and operations are the same as those of the scroll-type water vapor pumping apparatus 100 shown in FIG. 4, and the same parts are denoted by the same reference numerals. FIG. 6 is a side sectional view showing an embodiment in which the rolling bearing of the present invention is applied to a swash plate type compressor device. The illustrated swash plate type compressor device 160 includes a compression mechanism 170 that compresses a fluid such as air sent to an electrode of a fuel cell by reciprocating of a double-headed piston 172 accompanying rotation of a swash plate 171, and a motor spindle of a drive motor 181. Drive motor section 180 that drives compression mechanism section 170 by rotation of 182
And In the compression mechanism 170, the double-ended piston 172 is connected to the crank chamber 163 of the cylinder block 161.
It is provided so as to be able to reciprocate along the axial direction of the motor main shaft 182, and is connected to the swash plate 171 via the shoe 173. The swash plate 171 is rotatably inserted into the outer peripheral surface of the motor main shaft 182 so as to be integrally rotatable with the motor main shaft 182, and is rotatably mounted on a support member 162 provided in the cylinder block 161 via a thrust bearing 174. Supported. In the drive motor section 180, the drive motor 181 has a rotor 183 fitted on the motor main shaft 182.
And a stator 185 provided on the outer peripheral side of the rotor 183 and having the coil 184 wound thereon, are connected to the motor housing 18.
6. The motor main shaft 182 is located on the left side in FIG. 6 from the substantially center in the axial direction, and a pair of left and right rolling bearings 18 of the present invention in FIG.
7, while being rotatably supported by the motor housing 186, and being rotatably supported by the support member 162 via a pair of left and right rolling bearings 175 of the present invention in FIG. Have been. In the swash plate compressor 160 constructed as described above, when power is supplied to the drive motor 181, the motor main shaft 182 rotates, and the rotation is performed by the swash plate 171.
, And transmitted to the double-headed piston 172 via the shoe 173. The double-headed piston 172 reciprocates along the axial direction in the crank chamber 163 with the rotation of the motor main shaft 182, thereby sucking and compressing air and the like and discharging the air and the like to the electrode side of the fuel cell. FIG. 7 is a side sectional view showing an embodiment in which the rolling bearing of the present invention is applied to a screw compressor device. Screw-type compressor device 19 shown
Numeral 0 denotes a compression mechanism unit 200 that compresses a fluid such as air sent to an electrode of the fuel cell by rotating the main rotor 201 and the sub-rotor 202 by meshing with each other, and compressing a fluid by rotation of a motor main shaft 182 of a drive motor 181. A drive motor section 180 for driving the mechanism section 200. The drive motor unit 180 is the same as the swash plate type compressor device 160 shown in FIG. 6, and the same reference numerals are given and the description is omitted. In the compression mechanism 200, the main rotor 20
The first rotor 202 and the sub-rotor 202 are each formed in a corresponding spiral shape, and are rotatable in cooperation with each other by meshing with each other. The main rotor 201 is provided on the left rotating shaft 2 in FIG.
7 is rotatably supported by the housing 207 via a pair of left and right rolling bearings 203 of the present invention in FIG. 7, and the rotating shaft 201a on the right side in FIG. 7 is rotatable by the housing via the rolling bearing 204 of the present invention. It is supported by. The sub-rotor 202 is connected to the rotation shaft 20 on the left side in FIG.
7 is rotatably supported by the housing 207 via a pair of left and right rolling bearings 205 of the present invention in FIG. 7, and the right rotating shaft 202a is rotated by the housing 207 via the rolling bearing 206 of the present invention in FIG. It is freely supported. A seal 208 is interposed between the main rotor 201 and the housing 207 on the inner side in the axial direction with respect to the rolling bearings 203 and 204 on the right and left rotating shafts 201a of the main rotor 201 in FIG. The rolling bearings 205,
A seal 209 is interposed between the housing 206 and the housing 207 on the inner side in the axial direction from the housing 206. The main rotor 201 and the sub-rotor 202 are interlocked via connecting gears 210 provided on the left rotating shafts 201a and 202a in FIG. Main rotor 20
7, a driven gear 211 is provided at the left end of the rotating shaft 201 a on the left side in FIG. 7. The driven gear 211 is a driving gear of the driving shaft 188 fitted to the motor main shaft 182 of the driving motor 181. 189. Therefore, the main rotor 201 controls the rotation of the motor main shaft 182 to the drive shaft 1.
88, the driving gear 189 and the driven gear 211. The rotation of the main rotor 201 is transmitted to the sub-rotor 202 via the connection gear 210. The drive shaft 188 is rotatably supported by the housing 213 via a pair of left and right rolling bearings 212 of the present invention in FIG. A seal 214 is interposed between the drive shaft 188 and the housing 213. In the screw compressor device 190 configured as described above, when power is supplied to the drive motor 181, the motor main shaft 182 rotates, and the rotation causes the drive shaft 188, the drive gear 189, and the driven gear 211 to rotate. The power is transmitted to the rotation shaft 201 a of the main rotor 201 via the main shaft 201. At the same time, the connecting gear 21 is rotated from the rotating shaft 201a of the main rotor 201.
0 to the rotation shaft 202a of the sub-rotor 202. The main rotor 201 and the sub-rotor 202 engage and rotate, thereby sucking / compressing air and the like, and discharging the air and the like to the electrode side of the fuel cell. EXAMPLES The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereto. [Production of test cage] Kureha Chemical Industry Co., Ltd.
“KF Polymer T- # 850CF” (Example 1), “Fortron KPS1140” manufactured by Polyplastics Co., Ltd.
A1 "(Example 2)," VICT "manufactured by Sumitomo Chemical Co., Ltd.
REX450CA30 "(Example 3), DSM JSR
"Stanyl TS200F6" manufactured by Engineering Plastics Co., Ltd.
(Example 4) and polyamide 46 "Unreinforced product Stan"
Using "yl TW341" (Comparative Example 1), a crown-shaped cage shown in FIG. 2 was molded using an inline screw injection molding machine. [Steam Spray Bearing Rotation Test] Each crown type cage was assembled in the following test bearing, and a steam spray bearing rotation test (assuming a steam pumping device) was performed under the following conditions. The rate of change was measured. Table 3 shows the results.・ Test bearing: 6200 (inner diameter: 10 mm, outer diameter: 30 m)
g, width: 9 mm, with seal) ・ Grease: ENS grease (urea-ester type),
Made by Nisseki Mitsubishi Co., Ltd., filling amount: 0.35 g ・ Load: Fa30N, Fr10N ・ Rotation speed: 50,000 min ^-1 (inner ring rotation) ・ Steam spray amount: 3.0 kg / h (from one end face of the bearing,
(Spray with a steam humidifier) ・ Measurement time: 50, 200, 500 h As is apparent from Table 3, in Examples 1 to 3, the swelling of the cage is smaller than that of Comparative Example 1, and therefore, the increase in the restraining force on the rolling elements of the cage caused by the swelling. No increase in bearing torque was observed. As described above, since the rolling bearing of the present invention is provided with the retainer made of the resin composition having a low water absorption, the rolling bearing of the present invention has a stable bearing torque even when moisture enters the inside of the bearing. The holding function is maintained and the life is extended, and it can sufficiently withstand use in a severe water environment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an example of a rolling bearing of the present invention. FIG. 2 is a perspective view showing a crown type cage. FIG. 3 is a cross-sectional view showing an example of a steam pumping device (impeller type steam pumping device) used for a fuel cell. FIG. 4 is a cross-sectional view showing another example (scroll type steam pumping device) of a steam pumping device used for a fuel cell. FIG. 5 is a cross-sectional view showing another example of the scroll-type steam pumping device. FIG. 6 is a cross-sectional view showing another example (swash plate type steam pumping device) of the steam pumping device used for the fuel cell. FIG. 7 is a cross-sectional view showing another example (screw-type steam pumping device) of the steam pumping device used for the fuel cell. [Description of Signs] 1 Outer ring 2 Inner ring 3 Rolling element (ball) 4 Cage 5 Sealing device 6 Mounting fitting part 7 Fitting groove 8 End part 9 Seal groove 10 Lip part 41 Base part 42 Pocket 43 Elastic piece

Claims (1)

Claims: 1. A seal device for rotatably holding a plurality of rolling elements between an outer ring and an inner ring via a retainer and closing an end opening of a portion where the rolling elements are installed. Wherein the retainer is a molded article of a resin composition having a water absorption of 1.5% by weight or less when immersed in water at 23 ° C. for 24 hours. And rolling bearing.