JP2002130295A - Manufacturing method of plastic holder for rolling- element bearing, and the rolling-element bearing equipped with the holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a plastic holder for a rolling- element bearing that is inexpensive and is hardly deformed, even if it is used in a rolling-element bearing which operates at a high-speed revolution. SOLUTION: After forming resin into a shape of a holder, the holder is subjected to heat treatment at a temperature higher than the glass-transition temperature of the resin, and lower than the melting point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a plastic cage for a rolling bearing suitably used for a rolling bearing used under high-temperature and high-speed conditions. The present invention relates to a method for manufacturing a plastic cage for a rolling bearing suitably used for a rolling bearing used for a main shaft of a machine or the like.

[0002] The present invention also relates to a rolling bearing provided with a plastic retainer obtained by the manufacturing method.

[0003]

2. Description of the Related Art In general, cages used for rolling bearings are classified into metal cages and plastic cages according to their materials. Press holder, waveform holder,
There is a hollow cage and the like, and a press cage and a waveform cage are manufactured by pressing a thin metal plate, and a hollow cage is manufactured by cutting a metal. The plastic retainer is manufactured by injection molding a synthetic resin or by cutting a resin material previously molded into an appropriate shape. As a cage for a rolling bearing used at a high speed rotation, a plastic cage has been frequently used because of the self-lubricating property and the lightness inherent to the synthetic resin.

[0004] Rolling bearings used at high speeds include mainly deep groove ball bearings and angular ball bearings. The deep groove ball bearing includes a plastic crown retainer 7 as shown in Figs. , And a plastic angular ball bearing retainer as shown in FIG. 9 is often used for the angular ball bearing. Here, the structure and the like of the crown-shaped retainer 7 made of plastic as shown in FIGS. 1 and 2 will be described.

The crown retainer 7 is formed integrally by injection molding a synthetic resin. The crown retainer 7 includes an annular main portion 8 and a plurality of pockets 9 provided on one surface of the main portion 8.
Is formed from a pair of elastic pieces 10 and 10 which are arranged facing each other at an interval. The mutually opposing surfaces of the pair of elastic pieces 10, 10 constituting each pocket 9 are generally concentric spherical concave surfaces. However, there is a case where each surface is a cylindrical surface. Such a crown-shaped cage 7 is
By pushing a ball 5 described later between the pair of elastic pieces 10 and 10 while elastically expanding the space between the elastic pieces 10 and 10, the ball 5 is rollably held in each pocket 9. Can be.

FIG. 3 shows a deep groove ball bearing incorporating the above-described crowned cage 7. In this deep groove ball bearing, an inner ring 2 having an inner raceway 1 on an outer peripheral surface and an outer race 4 having an outer raceway 3 on an inner peripheral surface are arranged concentrically, and a plurality of balls 5 held by a crown retainer 7 are provided. Is provided between the inner raceway 1 and the outer raceway 3 so as to roll freely. At both ends of the inner peripheral surface of the outer ring 4, a ring-shaped shield plate 6 is provided, respectively.
The outer peripheral edge portion of the ball 6 is locked, and the grease present at the installation portion of the ball 5 leaks to the outside, or dust floating outside enters the installation portion due to both shield plates 6 and 6. To prevent them from doing so.

Conventionally, as a material of such a plastic retainer, a so-called engineering plastic or phenol resin laminated material such as polyamide (nylon), polyacetal, polybutylene terephthalate, polyphenylene sulfide (PPS), fluororesin, or polyimide has been used. It has been used alone or in the form of a composite material reinforced by blending short fibers such as glass fiber and carbon fiber.

[0008] Among these materials, thermoplastic resin which can be injection-molded is often used as a material for plastic retainers because of a good balance between production cost and performance, and excellent performance has been confirmed under moderate environmental conditions. Have been.

[0009]

However, these thermoplastic engineering plastics generally have an extremely low elastic modulus and strength or an increased creep depending on the operating temperature, and therefore are not suitable for rolling bearings used at high speeds. When used, the cage may be deformed and come into contact with the inner peripheral surface of the outer ring, or in the worst case, it may fall off or be damaged, and may not function as a cage.

[0010] For example, recently, in the case of a ball bearing incorporated in a rotation supporting portion of an alternator, a high temperature and high speed (1
(30 ° C. or higher, DmN ≧ 600,000) in many cases. Under such conditions of use, the cage in the ball bearing rotates at high speed together with the grease existing between the outer peripheral surface of the inner ring 2 and the inner peripheral surface of the outer ring 4. During such high-speed rotation, the cage has a radial outward force based on centrifugal force,
A complex force is applied that combines the restraining force (force in the rotating direction) based on the revolution of the ball 5 and the grease stir resistance. Then, due to such a complicated force, the retainer repeats an irregular movement and receives a complicated external stress accompanied by an impact.

[0011] In the case of a conventional synthetic resin crown-shaped cage (not subjected to any special treatment) obtained by injection molding a material reinforced with nylon 66, nylon 46, PPS or the like with glass fiber or carbon fiber, If the operation is continued for a long time under the above-mentioned use conditions of high temperature and high speed rotation, elastic deformation or plastic deformation occurs due to the action of centrifugal force. As a result, the gap between the inner surface of the pocket 9 and the rolling surface of the ball 5 increases, and the inner surface of the pocket 9 wears due to the force received from the rolling surface of the ball 5. When the gap becomes large, the following problem occurs.

First, the cage vibrates finely with the rotation of the rolling bearing, which not only further promotes wear of the pocket 9 but also generates harmful vibration and noise. And, second, as a result of the restraint of the cage by the ball 5 being released,
The cage is partially or totally displaced, and a part of the cage rubs against the mating surface. For example, the elastic pieces 10, 10 constituting the pocket 9 are displaced radially outward due to centrifugal force, and the outer peripheral surfaces of the distal end portions of the elastic pieces 10, 10 and the inner peripheral surface of the outer ring 4 rub against each other (FIG. 3). reference). Further, as a result of the entire cage being displaced in the axial direction, one axial surface of the main portion 8 (the surface opposite to the surface on which the elastic piece 10 is provided) and the inner surface of the shield plate 6 rub against each other (FIG. 3). reference). As described above, when a part of the cage rubs against the mating surface, the temperature of the part increases due to frictional heat, which causes a failure such as image sticking.

In recent years, polyethersulfone (PES), polyetherimide (PEI), polyamidoimide (PAI), and polyethersulfone (PEI) have been used as materials for plastic cages for rolling bearings used in high-temperature environments exceeding 150 ° C. Plastic polyimide, polyetheretherketone (PE
So-called super-engineering plastics such as EK) and polyether nitrile (PEN) have been proposed.

However, there is a problem that both of these materials and their processing costs are very expensive. Further, although it has better rigidity and creep resistance at high temperatures than general engineering plastics, it cannot be said that it has sufficient dimensional stability because it is used at a correspondingly high temperature. On the other hand, various attempts have been made to improve the rigidity and creep resistance of such a plastic cage. An example is shown below.

First, there is a method in which a mold is heated to a high temperature during injection molding and a cooling time is lengthened. However, there is a limit to the temperature of the mold, and the molding cycle becomes longer, so that the production cost rises. Further, the effect obtained by such a method cannot be said to be sufficient. Second, there is a synthetic resin crown retainer described in Japanese Utility Model Laid-Open No. 6-1848 (see FIG. 10). The retainer 7a has a connecting ring 11, and the connecting ring 11 connects the distal ends of the elastic pieces 10, 10 constituting the pocket 9. Even when the retainer 7a is used at a high speed, the elastic pieces 10, 10 can be centrifugally applied.
Is prevented from being displaced radially outward. As a result, it is possible to prevent the outer peripheral surface of the distal end portion of each of the elastic pieces 10, 10 from rubbing against the inner peripheral surface of the outer ring during high-speed rotation.

Thirdly, there is a synthetic resin crown retainer described in Japanese Utility Model Laid-Open No. 6-8821 (see FIGS. 11 and 12). The retainer 7b has a concave portion 12 formed between adjacent pockets 9, 9 to reduce the weight, and a metal reinforcing plate 13 is attached to prevent deformation of each pocket 9, 9. ing. Fourth, there is a synthetic resin crown retainer described in JP-A-8-145061 (see FIGS. 13 and 14). The retainer 7c has a rigidity of the main portion 8 improved by a metal plate 14 provided on the other surface in the axial direction of the main portion 8 (the surface opposite to the surface on which the elastic pieces 10 are provided). is there.
Even if such a retainer 7c is used at high speed rotation,
The distal ends of the elastic pieces 10, 10 are prevented from being displaced radially outward due to centrifugal force. As a result, it is possible to prevent the outer peripheral surface of the distal end portion of each of the elastic pieces 10, 10 from rubbing against the inner peripheral surface of the outer ring during high-speed rotation.

However, the above-mentioned Japanese Utility Model Laid-Open No. 6-1848.
JP, JP-A-6-8821, JP-A-8-145
The cage described in Japanese Patent No. 061 is excellent in the effect of preventing deformation of the cage, but each requires a separate member, so that the dimension in the axial direction becomes large and interference with the seal (shield plate) occurs. There is fear. In addition, since separate members are used together, the cost increases.

Therefore, the present invention solves the above-mentioned problems of the prior art, and is less likely to be deformed even when used in a rolling bearing used at high speed rotation, so that the durability of the rolling bearing is sufficiently exhibited. An object of the present invention is to provide a method for manufacturing a low-cost plastic cage for rolling bearings, which can be performed. Another object of the present invention is to provide an inexpensive rolling bearing that has excellent durability at high speed rotation and is inexpensive.

[0019]

In order to solve the above problems, the present invention has the following arrangement. That is, the method for manufacturing a plastic cage for a rolling bearing according to claim 1 according to the present invention comprises, after molding the resin into the shape of the cage,
The heat treatment is performed at a temperature equal to or higher than the glass transition temperature and lower than the melting point of the resin.

With such a configuration, sufficient rigidity and creep resistance at high temperatures can be imparted to the cage, so that the cage can be used even in a rolling bearing used at high speed rotation. The risk of deformation is small. Further, according to such a method, since it is not necessary to use a separate member, the cage can be manufactured at low cost. Also,
According to a second aspect of the present invention, there is provided a rolling bearing including a plastic cage manufactured by the method for manufacturing a plastic cage for a rolling bearing according to the first aspect.

With such a configuration, since the cage has sufficient rigidity and creep resistance at high temperatures and is hardly deformed even under severe use conditions, the rolling bearing is used at high speed rotation. be able to. Further, since the cage is inexpensive, the rolling bearing can be manufactured at low cost. The plastic cage manufactured by the method for manufacturing a plastic cage for a rolling bearing according to the present invention exhibits excellent heat resistance, oil resistance, chemical resistance, dimensional stability, and toughness, as well as high mechanical properties (strength, Stiffness and creep resistance), the cage is less likely to be deformed even when used in a rolling bearing used at high speed rotation, and the durability of the rolling bearing does not decrease. The details are described below.

The resin used in the present invention is not particularly limited, but is preferably a thermoplastic resin, and particularly has a glass transition temperature of 30 ° C. or higher and a melting point of 200 ° C.
The above crystalline resins are preferred. This is because the amorphous resin generally has high-temperature rigidity and excellent heat resistance, but does not have sufficient resistance to oil and chemicals, and easily causes environmental stress cracks.

On the other hand, a resin having a glass transition temperature of less than 30 ° C. or a melting point of less than 200 ° C. is inferior in rigidity and creep resistance, and cannot exhibit sufficient performance. For example, resins satisfying such conditions include polyamides (nylon 6, nylon 66, nylon 46, nylon 6/10, nylon 6/12, nylon 66 / 6I, nylon 66 / 6T, nylon MXD6, nylon 9T,
Or a mixture of two or more of these), polybutylene terephthalate, polyethylene terephthalate, polyphenylene sulfide (PPS), polyamide imide (PAI), thermoplastic polyimide, polyether ether ketone (PEEK), polyether nitrile (PE
N) and the like.

Depending on the purpose, such resins may contain 10
Up to 50 wt% of fibrous filler may be added. Since the fibrous filler has the effect of improving the rigidity of the cage and improving the dimensional accuracy, it is appropriately added as necessary. Although the type of the fibrous filler is not particularly limited, glass fiber, carbon fiber, metal fiber,
Aramid fiber, aromatic polyimide fiber, liquid crystal polyester fiber, silicon carbide fiber, alumina fiber, boron fiber,
Asbestos, silicon carbide whiskers, silicon nitride whiskers, alumina whiskers, aluminum nitride whiskers, wollastonite, potassium titanate whiskers,
Aluminum borate whisker, zinc oxide whisker,
Examples include magnesium oxide whiskers, mullite whiskers, calcium carbonate whiskers, graphite whiskers, and magnesium oxysulfate whiskers. Among these fibrous fillers, glass fibers and carbon fibers are preferable because of their good reinforcing properties.

The form of the fibrous filler preferably has an aspect ratio of 3 or more. This is because if it is less than 3, the reinforcing effect of the fibrous filler is not sufficiently exhibited, and the cage becomes fragile. Further, the fiber diameter is not particularly limited, the average fiber diameter is 0.2 ~ 30μ
m, more preferably 3 to 20 μm. Because, when the average fiber diameter is smaller than 0.2 μm, the fibers may aggregate when mixed with the resin as the base material, and the dispersion of the fibers may be non-uniform.
If the average fiber diameter is larger than 30 μm, the smoothness of the cage surface may be impaired, and the mating surface that has slid may be damaged. When the average fiber diameter is 3 to 20 μm, a preferable cage free of such a tendency can be obtained.

The proportion of the fibrous filler in the total resin composition is preferably 10 to 50 wt%. If the content exceeds 50% by weight, not only does the melt flowability of the resin composition significantly decrease and moldability deteriorates, but further improvement in mechanical properties and dimensional stability cannot be expected. This is because the deformability becomes extremely small.
Therefore, the cage may be damaged when the cage is formed or when the rolling bearing is assembled. Conversely, if the amount of the fibrous filler is less than 10 wt%, the effect of reinforcing the mechanical properties is small, and the heat resistance is also insufficient. In order to improve such performance, it is more preferable that the blending ratio is 20 to 45 wt%.

In order to improve the affinity between the resin and the fibrous filler in such a resin composition, to improve the adhesion between the fibrous filler and the resin, and to improve the dispersibility of the fibrous filler, a fibrous filler is used. The filler may be treated with a coupling agent such as a silane-based coupling agent or a titanate-based coupling agent, or a surface treatment agent for other purposes. Various additives may be added to the resin or the resin composition as long as the object of the present invention is not impaired. For example, solid lubricants such as graphite, hexagonal boron nitride, fluoromica, ethylene tetrafluoride resin powder, tungsten disulfide, molybdenum disulfide, etc., clay, talc, calcium carbonate, zinc carbonate, silica, alumina, magnesium oxide, silica Calcium silicate, asbestos, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, aluminum hydroxide, calcium hydroxide, barium sulfate, potassium bright bang, sodium bright bun, iron bright bun,
Inorganic powders such as glass balloon, carbon black, zinc oxide, antimony trioxide, boric acid, borax, zinc borate, zeolite, hydrotalcite, organic powder, lubricating oil, plasticizer, rubber, resin, antioxidant, heat stable Agents, UV absorbers, light protectants, flame retardants, antistatic agents, release agents, flow improvers, thermal conductivity improvers, non-tackifiers, crystallization accelerators, nucleating agents, pigments, dyes And the like.

The method of mixing these additives and various additives such as fibrous fillers with the resin is not particularly limited, and a conventional method can be used without any problem. For example, it is possible to melt-knead each separately, and after preliminarily mixing these materials with a mixer such as a Henschel mixer, a tumbler, a ribbon mixer, and a ball mill,
It can also be supplied to a melt mixer. As the melt mixer, a known melt kneader such as a single-screw or twin-screw extruder, a kneading roll, a pressure kneader, a Banbury mixer, and a Brabender plastograph can be used. The temperature at the time of melt-kneading is not particularly limited, but is appropriately selected within a temperature range where melting of the matrix resin sufficiently proceeds and does not deteriorate.

The method of molding the plastic cage for a rolling bearing of the present invention is not particularly limited. For example, it can be molded by a usual method such as injection molding, compression molding, transfer molding and the like. Among these, the injection molding method is preferable because it is excellent in productivity and an inexpensive cage can be manufactured.
The temperature of the heat treatment of the plastic cage for a rolling bearing of the present invention may be not less than the glass transition temperature of the resin and less than the melting point, and is more preferably 3 degrees below the glass transition temperature of the resin.
Not less than 0 ° C. higher temperature and not more than the deflection temperature under load of the resin or the resin composition (based on ASTM D648). This is because if the temperature is lower than the glass transition temperature of the resin, it is difficult to obtain the effect of the heat treatment, and if the temperature is higher than the melting point, it becomes difficult to maintain the shape of the cage. If the temperature is at least 30 ° C. higher than the glass transition temperature of the resin and is not more than the deflection temperature under load of the resin or the resin composition, there is no such concern at all.

The time for the heat treatment is not particularly limited, but is preferably 1 hour or more and 50 hours or less. If the time is less than 1 hour, the temperature of the retainer is hard to reach the set temperature uniformly, and there is a possibility that a sufficient effect by the heat treatment cannot be exerted. Conversely, even if heating is performed for 50 hours or more, further improvement in performance cannot be expected, and the cost will increase.

The atmosphere of the heat treatment is preferably performed in vacuum, in an inert gas, or in oil to prevent the resin from being oxidized and degraded. In addition, the kind of the plastic cage for rolling bearings of the present invention is not particularly limited, and examples thereof include a crown cage, a cage cage, a single cage, a waveform cage, and the like.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for manufacturing a plastic cage for a rolling bearing and a rolling bearing provided with the cage according to the present invention will be described in detail with reference to the drawings and tables. First, the raw materials (resin, fibrous filler, and the like) of the cage used in the examples and the comparative examples are collectively shown.

(1) Polyphenylene sulfide resin:
Kureha Chemical Industry Co., Ltd., Fortron KPS W-214 (2) Nylon 66 resin: Ube Industries, Ube Nylon 2120U (3) Nylon 46 resin: DSM, Stanyl T
W300 (4) Glass fiber: FES, manufactured by Fuji Fiber Glass Co., Ltd.
S-015-0413, fiber diameter 10 μm, average fiber length 0.5 mm (5) Carbon fiber: HTA-C6 manufactured by Toho Rayon Co., Ltd.
-S, fiber diameter 7 μm, average fiber length 6 mm Using a resin composition in which these raw materials were blended in the proportions shown in Table 1, a cage for a single-row deep groove ball bearing was manufactured, and various tests were performed.

The resin composition was prepared using a twin screw extruder (PC
M-30) to extrude and granulate (pelletize).
The fibrous filler was added by a quantitative side feeder in order to prevent breakage of the fibrous filler. The obtained pellets are dried, injection-molded by an in-line screw injection molding machine (NS40-5A) manufactured by Nissei Plastics Industry Co., Ltd., and a desired cage shape (outer diameter × inner diameter × width is 47 mm × 1).
7 mm x 14 mm cage for radial ball bearings).
In addition, the shape of the cage was a crown-shaped cage as shown in FIGS. 1 and 2. Since the structure is the same as that of the above-described conventional example, the description is omitted.

The cage thus obtained was subjected to a heat treatment under the conditions shown in Table 1. Mixing ratio of various materials (w
Table 1 shows the heat treatment conditions.

[0036]

[Table 1]

First, an experiment performed to confirm the effect of preventing the deformation of the cage will be described. In the experiment, a plastic retainer subjected to heat treatment (Example) and a plastic retainer not subjected to heat treatment (Comparative Example) were used, and these retainers were separated by an outer diameter × an inner diameter × a width of 47 mm × 17 mm ×
A 14 mm radial ball bearing (see FIG. 3; the structure is the same as the above-described conventional example, so the description is omitted), and a durability test was performed by rotating the bearing under grease lubrication. The conditions are shown below.

Radial load: 98N Test temperature: 140 ° C. or 180 ° C. Rotation speed: 20000 rpm (640,000 DmN) Rotation time: 100 hours (continuous operation) Then, the elasticity of these plastic retainers before and after the high-temperature durability test described above. The amounts of deformation of the tips of the pieces 10 and 10 were measured. Regarding this, FIG.
This will be described with reference to FIG. Adjacent pockets 9,
9, a point α on the outer peripheral edge of the tip of the elastic pieces 10
The distance x between a straight line a connecting α and a straight line b parallel to the straight line a and in contact with the outer peripheral surface of the main part 8 was determined, and the deformation amount of the distal end portions of the elastic pieces 10, 10 was evaluated based on the distance x. . If the straight line a is located radially inward of the straight line b (upper side of FIG. 4A), the value of the distance x is set to minus (-), and the straight line a is located radially outward of the straight line b. If it exists on the lower side of FIG. 4A), the value of the distance x is added (+).
And Table 1 shows the results of the measurements performed in this manner.

As is clear from Table 1, the cages of Examples 1 to 5 subjected to the heat treatment showed that the elastic pieces 10 constituting the pockets 9 were not deformed even when they were rotated at a high temperature and at a high speed. Even if it happened, it was extremely small (no difference between the initial dimensions in the table and the dimensions after the test or extremely small). Therefore,
The outer peripheral surfaces of the distal ends of the elastic pieces 10 and 10 and the inner peripheral surface of the outer ring 4 do not rub against each other (see FIG. 3). However, the cages of Comparative Examples 1 to 4 which were not subjected to the heat treatment were all elastic pieces 1
The deformation amount of 0 was large.

Next, in order to confirm the strength of the plastic cage due to the difference in atmosphere during the heat treatment, nylon 46 was used.
A cage is manufactured using a resin composition in which glass fiber is mixed with a resin at a ratio of 30% by weight, and subjected to a heat treatment at 230 ° C. for 20 hours in vacuum, in nitrogen, in silicon oil, and in the atmosphere. An annular tensile test was performed. Further, as a reference value, an annular tensile test of the cage not subjected to the heat treatment was also performed.

Test cages were manufactured in the same manner as in Examples 1 to 5 and Comparative Examples 1 to 4, and were also used for radial ball bearings having an outer diameter × inner diameter × width of 47 mm × 17 mm × 14 mm. It was a crown cage. The method of the ring tension test is shown in FIG.
This will be described with reference to FIG. The cage 7 is mounted on an annular tensile test jig J such that a straight line connecting the gate 7G and the weld 7W of the cage 7 is horizontal, and a tensile tester T (Autograph AG-10KNG, manufactured by Shimadzu Corporation) is attached. ) Was pulled in the vertical direction in FIG. 5 at a pulling speed of 10 mm / min, and an annular tensile test was performed. Table 2 shows the test results.

[0042]

[Table 2]

As is clear from Table 2, the cages of Examples 6 to 8 which were subjected to the heat treatment in vacuum, in nitrogen, and in silicone oil were compared with the reference values which were the cages without heat treatment. In each case, there was almost no decrease in strength. Therefore, even if an excessive force acts on the cage during rotation of the rolling bearing, the cage is not easily damaged. However, the strength of the cage of Comparative Example 5, which was subjected to the heat treatment in the atmosphere, was significantly reduced due to oxidation deterioration.

Next, in order to confirm the high-temperature and high-speed durability of the cage by the heat treatment temperature, a glass fiber was added to the PPS resin.
The resin composition blended at a ratio of 0% by weight was molded into a cage shape, and heat-treated at various temperatures in nitrogen for 20 hours to produce a cage. The glass transition temperature of the PPS resin subjected to the test was 85 ° C., the melting point was 283 ° C., and the deflection temperature under load of the resin composition was 260 ° C.

The cage for the test was manufactured in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 5, and was used for a radial ball bearing having an outer diameter × inner diameter × width of 47 mm × 17 mm × 14 mm. It was a crown cage. The method of the high temperature high speed durability test is as follows.
The same method as in Examples 1 to 5 and Comparative Examples 1 to 4 was used except that the temperature was changed to a continuous operation of 200 ° C. for 10 hours. The results of the experiment performed in this manner are shown in the graph of FIG. Note that the initial dimensions of all the cages are -0.7 mm.

As apparent from FIG. 6, the cage subjected to the heat treatment at a temperature equal to or higher than the glass transition temperature of the resin and lower than the deflection temperature under load of the resin composition has the pocket 9 even when rotated at a high speed at a high temperature. The deformation of the constituent elastic pieces 10 did not occur, or was very small. In particular, the cage subjected to the heat treatment at a temperature higher by about 30 ° C. than the glass transition temperature had a small amount of deformation. Therefore, the elastic pieces 10, 1
0 does not rub against the outer peripheral surface of the outer ring 4 (see FIG. 3). The cage subjected to the heat treatment at a temperature exceeding the deflection temperature under load of the resin composition could not be incorporated into the rolling bearing because the entire cage was deformed.

Next, in order to confirm the high-temperature and high-speed durability of the cage based on the amount of the fibrous filler in the resin composition, a resin composition in which glass fibers were mixed with nylon 66 resin in various ratios was used. Formed into a shape and vacuumed at 200 ° C for 10
A heat treatment was performed for a time to manufacture a cage. Test cages were manufactured in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 5, and the model number and shape were also outer diameter × inner diameter × width of 47 mm × 17 m.
A crown type cage for radial ball bearings of mx 14 mm was used. The method of the high-temperature high-speed durability test is as follows.
The same method as in Examples 1 to 5 and Comparative Examples 1 to 4 was performed except that the continuous operation was performed at 00 rpm (704,000 DmN) for 10 hours. The results of the experiment performed in this manner are shown in the graph of FIG. The initial size of each cage is-
0.7 mm.

As is clear from FIG.
The cage made of the resin composition added with 0 wt% or more and subjected to a predetermined heat treatment does not cause deformation of the elastic piece 10 constituting the pocket 9 even if it is rotated at a high temperature and at a high speed. It was small. Therefore, the elastic piece 1
0 and the inner peripheral surface of the outer race 4 do not rub against each other.

Next, in order to confirm the high-temperature and high-speed durability of the cage by the heat treatment time of the plastic cage, a resin composition in which carbon fiber was blended with nylon 46 resin at a ratio of 25% by weight was formed into a cage shape. And 240 ° C in vacuum
The heat treatment was performed for each hour to produce a cage. The cage for the test was manufactured in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 5, and the model number and the shape were also outer diameter × inner diameter × width of 47 mm × 17.
A crown cage for radial ball bearings of mm × 14 mm was used.
The method of the high-temperature high-speed durability test is as follows.
The same method as in Examples 1 to 5 and Comparative Examples 1 to 4 was used except that the continuous operation was performed at 000 rpm (640,000 DmN) for 10 hours. The results of the experiment performed in this manner are shown in the graph of FIG. Note that the initial size of each of the retainers is -0.0.
7 mm.

As is apparent from FIG. 8, the heat treatment time is set to 1
In the cage for which the time was longer than that, even when the cage was rotated at a high speed under a high temperature, the deformation of the elastic piece 10 constituting the pocket 9 did not occur or was very small. Therefore, the outer peripheral surface of the distal end portion of the elastic piece 10 does not rub against the inner peripheral surface of the outer ring 4. As described above, the plastic cage for the rolling bearing of the present embodiment has almost no deformation even when the rolling bearing is rotated at a high temperature at a high speed, so that a part of the cage does not rub against the inner peripheral surface of the outer ring, Stable bearing performance can be maintained over a long period. In other words, failure such as seizure hardly occurs even under severe conditions, and it is possible to improve the durability and reliability of the rolling bearing incorporating the retainer and various mechanical devices incorporating the rolling bearing.

The present embodiment is an example of the present invention, and the present invention is not limited to the present embodiment. For example, the type of resin, fiber, and cage
Neither is limited to the above-described ones, and may be, for example, those exemplified in the section of means for solving the problems. In addition, although the deep groove ball bearing has been described as an example of the rolling bearing, the present invention can be applied to various other types of rolling bearings. For example, radial type rolling bearings such as cylindrical roller bearings, tapered roller bearings, self-aligning roller bearings, and angular ball bearings, and thrust type rolling bearings such as thrust ball bearings and thrust roller bearings. Although the materials of the outer ring and the rolling elements are not particularly exemplified, they may be made of steel or ceramics.

[0052]

As described above, according to the method for manufacturing a plastic cage for a rolling bearing of the present invention, sufficient rigidity and creep resistance can be imparted to the cage, so that the cage can be used at high speed rotation. Even when the cage is used for a rolling bearing, the possibility that the cage is deformed is small. Further, the cage can be manufactured at low cost.

Further, the rolling bearing of the present invention has excellent durability at high speed rotation and is inexpensive.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating the structure of a crown-shaped retainer according to the present embodiment.

FIG. 2 is a perspective view illustrating the structure of the crown type cage according to the present embodiment.

FIG. 3 is a cross-sectional view illustrating a structure of a deep groove ball bearing incorporating the crown cage of the present embodiment.

FIGS. 4A and 4B are a partial plan view and a partial side view illustrating a method for measuring the amount of deformation of the distal end portion of an elastic piece before and after a high-temperature durability test.

FIG. 5 is an explanatory view showing a method of an annular tension test.

FIG. 6 is a graph showing a correlation between a heat treatment temperature and a deformation amount of a tip portion of an elastic piece.

FIG. 7 is a graph showing the correlation between the amount of glass fiber added and the amount of deformation of the tip of the elastic piece.

FIG. 8 is a graph showing a correlation between a heat treatment time and a deformation amount of a tip portion of an elastic piece.

FIG. 9 is a perspective view illustrating the structure of an angular ball bearing retainer.

FIG. 10 is a partial perspective view illustrating the structure of a first conventional example.

FIG. 11 is a perspective view illustrating the structure of a second conventional example.

FIG. 12 is a sectional view taken along line AA of the cage of FIG. 11;

FIG. 13 is a partial perspective view illustrating the structure of a third conventional example.

FIG. 14 is a sectional view of the retainer of FIG. 13 taken along line BB.

[Explanation of symbols]

 5 ball 7 cage 8 main part 9 pocket 10 elastic piece

Continued on the front page (72) Inventor Shigeaki Aihara 1-5-50 Kugenuma Shinmei, Fujisawa-shi, Kanagawa Nippon Seiko Co., Ltd. Incorporated F term (reference) 3J101 AA02 AA32 AA42 AA54 AA62 BA25 BA50 DA14 EA31 EA36 EA76 FA31 FA35 FA44 FA60 GA24 GA31 GA60

Claims (2)

[Claims] 1. A method for manufacturing a plastic cage for a rolling bearing, comprising: after molding a resin into a shape of a cage, performing a heat treatment at a temperature equal to or higher than a glass transition temperature and lower than a melting point of the resin. 2. A rolling bearing comprising a plastic cage manufactured by the method for manufacturing a plastic cage for a rolling bearing according to claim 1.