JP2017020597A - Manufacturing method of wave-type cage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for inexpensively manufacturing a wave-type cage which is formed of a fiber-reinforced thermoplastic resin, light in weight and excellent in rigidity and stiffness by the smallest number of processes and part items without causing problems such as the lowering of the rigidity and the progress of wear.SOLUTION: By press-molding fiber-reinforced thermoplastic resin-made annular plate materials 5, 6 by using balls as a part of a press mold in a state that the balls 4 are arranged between an inner ring 2 and an outer ring 3 of a ball bear 1, a pair of annular bodies 13, 20 which correspond to contours of substantially-half spherical portions of the balls, and have pockets 11, 18 having clearances α, β between the balls and themselves are manufactured, and both the annular bodies which sandwich the balls therebetween are integrated to each other by the thermal fusion of connecting parts 12, 19 which connect the adjacent pockets, thus forming a wave-type cage 21.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a corrugated cage.

In order to reduce the weight of a rolling bearing, it has been studied to form a cage, which has been conventionally made of metal, using a fiber reinforced resin, particularly a fiber reinforced thermoplastic resin, which has high strength and rigidity and is lightweight.
As the fiber reinforced thermoplastic resin, a long fiber-like continuous carbon fiber or the like, which is highly filled, is preferably used because of its excellent strength and rigidity.

For example, in Patent Document 1, a so-called machined cage is formed by forming a pocket on a ring-shaped substrate formed of the above-described fiber-reinforced thermoplastic resin by a cutting process (a machined process) like a conventional metal substrate. Proposed to manufacture.
However, in the above-described configuration, there is a concern that the fiber may be exposed or cut on the processed surface, that is, the inner surface of the pocket during the cutting process for forming the pocket, thereby reducing the strength or promoting wear. The

In Patent Documents 2 and 3, a pair of annular bodies having a plurality of pockets corresponding to the outer shape of the approximate hemisphere of a ball are formed of fiber-reinforced thermoplastic resin, and the pair of such It describes that a corrugated cage is manufactured by riveting an annular body at a connecting portion connecting adjacent pockets.
However, in the above configuration, since it is necessary to perform a drilling process for forming a hole through which the rivet is inserted into the annular body, problems such as fiber exposure and cutting, and particularly a decrease in strength of the joint portion, etc. still occur. End up. In addition, the number of parts and the weight increase due to the need for rivets, and there are problems that the manufacturing process becomes complicated because drilling and riveting are required.

In Patent Document 4, an engaging claw and an engaging hole are integrally formed in the coupling portion of the annular body that is the basis of the corrugated cage, and a pair of annular bodies are connected to the engaging claw and the engaging hole. It is described that the corrugated cage is manufactured by integrating the two together.
However, the above-described annular body has a complicated structure and requires high dimensional accuracy in order to ensure the accuracy of engagement between the engagement claw and the engagement hole.

  Therefore, the annular body must be manufactured by injection molding of a fiber reinforced thermoplastic resin. However, a fiber reinforced thermoplastic resin containing continuous fibers in a long fiber shape cannot basically be injection molded, and a fiber that can be injection molded. Even if it is a fiber reinforced thermoplastic resin containing, since the filling amount of the fiber is limited in consideration of injection moldability, there is a problem that sufficient strength and rigidity cannot be imparted to the corrugated cage.

  In addition, since a complicated mold for injection molding needs to be prepared for each shape and size of the wave cage, there is a problem that the manufacturing cost of the wave cage is increased.

JP 2006-207642 A JP-A-4-236820 JP 2003-343567 A JP 2007-78029 A

  The object of the present invention is to make a corrugated cage made of a fiber-reinforced thermoplastic resin, which is lightweight and has excellent strength and rigidity, with as few processes and parts as possible without causing problems such as strength reduction and accelerated wear. Then, it is providing the manufacturing method for manufacturing at low cost.

The invention according to claim 1 is an annular plate (5) made of fiber-reinforced thermoplastic resin in a state in which balls (4) are mounted between the inner ring (2) and the outer ring (3) of the ball bearing (1). (6) is press-molded using the ball as a part of a press die, so that it corresponds to the outer shape of the hemisphere of the ball and has clearance (α) (β) between the balls. A step (first step) of producing a pair of annular bodies (13) and (20) that are the basis of a corrugated cage having a plurality of pockets (11) and (18), and the pair of annular bodies, A step (second step) of integrating the joints (12) and (19) connecting the adjacent pockets in a state in which the balls are sandwiched therebetween (second step),
It is a manufacturing method of the wave type | mold retainer containing this.

The invention according to claim 2 is that the one of the pair of annular bodies is manufactured by press molding and the other annular body is subsequently manufactured by press molding, while the previously manufactured annular body and the coupling portion It is a manufacturing method of the corrugated cage of Claim 1 made to integrate by heat welding of each other.
The invention according to claim 3 is a dimension in which the amount of press when producing at least one of the pair of annular bodies by press molding is added with a clearance (α) provided between the pocket and the ball. It is a manufacturing method of the corrugated cage of Claim 1 or 2 set to.

According to a fourth aspect of the present invention, the opening dimension of the pocket at the time of press molding is set to a dimension obtained by adding a clearance (β) provided between the pocket and the ball. A method for manufacturing the corrugated cage according to claim 1.
The invention according to claim 5 is the production of the corrugated cage according to any one of claims 1 to 4, wherein the fiber reinforced thermoplastic resin is formed by filling long fibers in a discontinuous manner. Is the method.

According to the first aspect of the present invention, in the first step, a wave cage is obtained by press molding using a ball mounted between an inner ring and an outer ring of a ball bearing as a part of the press mold. A pair of annular bodies is manufactured, and the fiber reinforced thermoplastic resin that is the basis of the annular body is made of fibers with an arbitrary fiber length at an arbitrary ratio without being restricted by injection molding. Can be filled.
Further, by performing press molding using the ball actually held as a part of the press die as described above, the dimensional accuracy of the pocket can be improved to be equal to or higher than that of injection molding.

In addition, it is possible to produce an annular body that is the basis of a corrugated cage having a predetermined shape and dimensions simply by setting the diameter and thickness of the annular plate material to predetermined values. There is also no need to prepare each separately according to the shape and dimensions of the corrugated cage.
Moreover, according to the invention described in claim 1, in the second step, by simply heat-bonding the joints connecting the adjacent pockets of the pair of annular bodies produced to each other and integrating the pair of annular bodies, The corrugated cage can be used without the need for cutting or drilling with fiber exposure or cutting, which can cause strength reduction or accelerated wear, or riveting with increased number of steps, parts and weight. Can be manufactured.

Compared with drilling for riveting, it is possible to increase the strength of the corrugated cage, in particular, to increase the strength of the corrugated cage, and to increase the life of the corrugated cage, coupled with the fact that the fiber can be highly filled. be able to.
Therefore, according to the first aspect of the present invention, a wave cage made of a fiber reinforced thermoplastic resin, which is lightweight and excellent in strength and rigidity, without causing problems such as strength reduction and accelerated wear, It is possible to manufacture at low cost with as few steps and parts as possible.

According to the invention described in claim 2, since the first and second steps can be carried out continuously, for example, the step of assembling a previously produced annular body is omitted, and the productivity of the corrugated cage is further increased. It can be improved.
Moreover, since each pocket can be individually formed by press molding on a one-to-one basis for each individual ball, the dimensional accuracy of each pocket can be further improved.

According to the third aspect of the present invention, the clearance is formed between the pocket and the ball by setting the pressing amount when pressing at least one of the pair of annular bodies to a dimension including the clearance. Since the clearance can be formed at the same time as the press molding without providing a separate process or the like, the number of processes can be further reduced and the productivity of the corrugated cage can be improved.
Further, the clearance amount can be mechanically accurately adjusted by the press amount at the time of press molding, and the pocket dimensional accuracy can be further improved.

  According to the invention described in claim 4, the clearance between the pocket and the ball is also set by setting the opening size of the pocket at the time of press molding to a size added with the clearance provided between the pocket and the ball. Since the clearance can be formed at the same time as the press molding without providing a separate process or the like, the number of processes can be further reduced and the productivity of the corrugated cage can be improved.

Further, the clearance amount can be mechanically accurately adjusted according to the size of the press die used for press molding, and the dimensional accuracy of the pocket can be further improved.
The annular plate that is the base of the annular body is obtained by, for example, laminating a plurality of prepregs formed from a fiber-reinforced thermoplastic resin into a sheet shape and integrating them with a hot press or the like so as to have a predetermined plate thickness. It is produced by punching in an annular shape.

In this case, according to the invention described in claim 5, by using a fiber reinforced thermoplastic resin in which long fibers are discontinuously filled, conventional carbon fibers and the like that are continuous in long fibers can be obtained. Good workability that cannot be obtained with a highly filled material can be secured.
Therefore, the workability and formability can be greatly improved, for example, when the sheet is molded or integrated by hot pressing, or when the produced plate material is press-molded to produce an annular body. Moreover, it can also suppress as much as possible that a fiber is cut | disconnected or exposed to a cross section when it pierce | punches circularly.

It is a perspective view which shows the external appearance of the ball bearing which incorporates the board | plate material used as the base of the waveform holder manufactured in the example of embodiment of the manufacturing method of this invention, and the said waveform holder. Figures (a) to (c) are cross-sectional views showing each stage of the first step in the manufacturing method of the above example. FIGS. (A) to (c) are cross-sectional views showing the second process from the stage following the first process in the manufacturing method of the above example.

Referring to FIG. 1, in the manufacturing method of this example, a plurality (9 in the figure) of balls 4 mounted between an inner ring 2 and an outer ring 3 of a ball bearing 1 are placed between the two wheels 2 and 3. In the figure, a pair of annular plate members 5 and 6 are prepared, which are the basis of a corrugated cage that is sandwiched from above and below.
The plate members 5 and 6 can be formed of various fiber-reinforced thermoplastic resins that can be press-molded and heat-welded.

In particular, as described above, a fiber-reinforced thermoplastic resin obtained by filling a long fiber into a thermoplastic resin in a discontinuous and random manner is preferably used.
Examples of the thermoplastic resin include polyamide resin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), amorphous polyarylate (PAR), polysulfone (PSF), polyether sulfone (PES), polyimide, and polyetherimide. (PEI), liquid crystal polymer (LCP), 1 type, or 2 or more types of engineering plastics, such as a fluororesin, or super engineering plastics are mentioned.

The fiber is preferably carbon fiber.
Carbon fiber has a higher thermal conductivity than, for example, glass fiber, and so has an excellent temperature rise prevention effect during rotation, and can suppress the deterioration of grease and extend the life of the ball bearing.
As the carbon fiber, polyacrylonitrile (PAN) type carbon fiber is particularly preferable from the viewpoint of productivity and environmental protection.

The fiber length of the fibers that are discontinuously filled in the thermoplastic resin is preferably 5 mm or more, and preferably 40 mm or less.
When the fiber length is less than this range, there is a possibility that a good reinforcing effect due to the long fiber shape cannot be obtained sufficiently. On the other hand, when the fiber length exceeds the above range, for example, when a fiber-reinforced thermoplastic resin is formed into a sheet shape to form a prepreg, or when plate members 5 and 6 are press-molded to produce an annular body There is a possibility that the workability and moldability of the resin may be lowered.

The filling amount when the fibers having the above-mentioned fiber length are discontinuously packed in the thermoplastic resin is preferably 30% by mass or more, and preferably 60% by mass or less.
If the filling amount is less than this range, a sufficient reinforcing effect may not be obtained. On the other hand, when the filling amount exceeds the above range, for example, a fiber reinforced thermoplastic resin is formed into a sheet shape to form a prepreg, or the plate members 5 and 6 are press molded to produce an annular body. There is a possibility that workability and formability may be reduced.

With reference to FIGS. 1 and 2 (a), in this example, with the balls 4 mounted between the inner ring 2 and the outer ring 3 of the ball bearing 1, first, the upper plate material 5 and the balls 4 are pressed. Used as a part and press-molded.
For press molding, an annular press die 9 is used together with the balls 4.
The press die 9 has, as shown in FIG. 2 (a), recesses 7 arranged on the lower surface at a predetermined number (9 in the case of the figure) arranged at equal intervals in the circumferential direction according to the outer shape and number of the balls 4. And a convex portion 8 projecting downward from between the adjacent concave portions 7.

The inner surface of each recess 7 is formed into a curved surface obtained by adding the thickness of the plate material 5 to the outer shape of a substantially hemispherical shape of the ball 4.
Further, the tip surface 10 of each convex portion 8 is formed in a planar shape parallel to the plane including the center P of each ball 4 and the same plane when the press molding shown in FIG. 2C is completed. Has been.

The press die 9 is heated to a temperature higher than the softening temperature of the fiber-reinforced thermoplastic resin by, for example, heating from a heating coil (not shown) during press molding.
Referring to FIGS. 2 (a) and 2 (b), while the plate material 5 is sandwiched between the press die 9 and the ball 4, the ball 4 is aligned with the concave portion 7 of the press die 9 and white in both figures. When the convex portion 8 is pushed between the balls 4 as indicated by the arrows, the plate material 5 is press-molded into a corrugated shape along the concave portions 7 and the convex portions 8 and the outer shape of the balls 4.

Then, referring to FIG. 2 (c), when the press die 9 is pushed in until the both surfaces of the plate 5 are in contact with the inner surface of the recess 7 and the outer surface of the ball 4 without a gap, a plurality of outer shapes corresponding to the approximate hemispherical shape of the ball 4 are obtained. The annular body 13 having a flat plate shape corresponding to the tip surface 10 of the convex portion 8 of the press die 9 described above is press-molded.
In this case, in this example, the press amount of the press die 9 is set to a size obtained by adding the clearance α to the hemisphere of the ball 4 and is set based on the opening size of the concave portion 7 of the press die 9. The opening dimension of the pocket 11 is set to a dimension obtained by adding clearance β to both sides of the ball 4, whereby the clearances α and β are provided between the pocket 11 and the ball 4.

Referring to FIG. 3 (a), in this example, following the press forming of the annular body 13, the lower plate member 6 is moved while maintaining the annular body 13 and the press die 9 in the state at the time of completion of the press forming. Similarly, the ball 4 is press-molded as a part of the press die.
In the press molding, an annular press die 14 is used together with the balls 4.
The press die 14 is configured similarly to the press die 9. That is, the press die 14 has, on the upper surface in the drawing, a predetermined number of concave portions 15 arranged at equal intervals in the circumferential direction according to the outer shape and the number of the balls 4 and convex portions protruding upward from between the adjacent concave portions 15. Part 16.

The inner surface of each recess 15 is formed into a curved surface obtained by adding the thickness of the plate material 6 to the outer shape of the substantially hemisphere of the ball 4.
Further, the front end surface 17 of each convex portion 16 is formed in a planar shape parallel to the plane including the center P of each ball 4 and the same plane when the press molding shown in FIG. 3C is completed. Has been.

During press molding, the press die 14 is heated to a temperature higher than the softening temperature of the fiber-reinforced thermoplastic resin by heating from a heating coil (not shown).
Referring to FIGS. 3 (a) and 3 (b), in a state where the plate material 6 is sandwiched between the press die 14 and the ball 4, the ball 4 is aligned with the concave portion 15 of the press die 14 and black in both drawings. When the convex portion 16 is pushed between the balls 4 as indicated by arrows, the plate 6 is pressed into a corrugated shape along the concave portions 15 and the convex portions 16 and the outer shape of the balls 4.

  Referring to FIG. 3C, when the press die 14 is pushed in until the both sides of the plate 6 are in contact with the inner surface of the recess 15 and the outer surface of the ball 4 without a gap, a plurality of shapes corresponding to the outer shape of the ball 4 substantially hemispherical The annular body 20 having a flat plate shape corresponding to the tip surface 17 of the convex portion 16 of the press die 14 described above is press-molded.

At the same time, in this example, the joint portion 19 of the press-formed annular body 20 is thermally welded to the joint portion 12 of the annular body 13 previously press-formed.
That is, in a state where both the coupling parts 12 and 19 are sandwiched between the front end surfaces 10 and 17 of the convex parts 8 and 16 of the press dies 9 and 14, they are heat-welded to each other by the press pressure and heat of the press dies 9 and 14. The
And by this heat welding, a pair of annular bodies 13 and 20 are integrated, and the waveform retainer 21 is manufactured.

  Further, when the annular body 20 is press-molded, in this example, the press amount of the press die 14 is set to a dimension in which the clearance α is added to the hemisphere of the ball 4 and the recess 15 of the press die 14 is formed. The opening dimension of the pocket 18 set based on the opening dimension is set to a dimension obtained by adding clearance β to both sides of the ball 4, whereby the clearance α between the ball 4 and the pocket 4 is set. , Β are provided.

Thereafter, when the press dies 9 and 14 are opened, the ball bearing 1 in which the balls 4 are held by the corrugated cage 21 is completed.
The clearances α and β set in the annular bodies 13 and 20 are predetermined values set for each model number within a range of about 140 μm to 320 μm, for example, depending on the model number of the ball bearing 1 incorporating the wave cage 21. You can do it.

The clearances α and β can be finely adjusted by controlling the welding conditions (press pressure, temperature), the welding area, and the like of the coupling portions 12 and 19 of the annular bodies 13 and 20.
Note that the configuration of the present invention is not limited to the example illustrated in the above description.
For example, as the fiber-reinforced thermoplastic resin, a long fiber-like continuous fiber filled or a short fiber-like highly filled fiber may be used as in the prior art.

The clearance may be formed by adjusting the press amount only in one of the pockets 11 and 18 of the annular bodies 13 and 20. In that case, for example, press molding may be performed by adding twice the clearance α to the press amount.
The annular bodies 13 and 20 may be individually press-molded using the balls 4 as a part of a press mold, and then combined to be thermally welded together to manufacture the corrugated cage 21.

The clearances α and β of the pockets 11 and 18 are formed, for example, by pressing the respective annular bodies 13 and 20 with the spacers sandwiched between the balls 4 and the plate members 5 and 6 and then removing the spacers. You may do it.
Further, for example, the predetermined clearances α and β may be formed only by the shrinkage by calculating the shrinkage of the fiber reinforced thermoplastic resin and adjusting the press molding condition.

  In addition, various changes can be made without departing from the scope of the present invention.

  1: ball bearing, 2: inner ring, 3: outer ring, 4: ball, 5, 6: plate material, 7, 15: concave portion, 8, 16: convex portion, 9, 14: press die, 10, 17: tip surface, 11, 18: pocket, 12, 19: coupling portion, 13, 20: annular body, 21: corrugated cage, P: center, α, β: clearance

Claims (5)

An annular plate made of fiber reinforced thermoplastic resin is press-molded using the ball as a part of a press die in a state where the ball is mounted between the inner ring and the outer ring of the ball bearing. A pair of annular bodies corresponding to the outer shape of the minute and provided with a plurality of pockets having a clearance between the balls, and a pair of annular bodies, A step of integrating by joining the connecting portions connecting the adjacent pockets in a state where the balls are sandwiched therebetween,
A method for manufacturing a corrugated cage.   One of the pair of annular bodies is produced by press molding, and then the other annular body is produced by press molding, and the previously produced annular body is integrated by thermal welding between the coupling portions. Item 2. A method for manufacturing a corrugated cage according to Item 1.   The wave according to claim 1 or 2, wherein a pressing amount when at least one of the pair of annular bodies is manufactured by press molding is set to a dimension including a clearance provided between the pocket and the ball. A method for manufacturing a mold cage.   4. The corrugated cage according to claim 1, wherein an opening dimension of the pocket at the time of the press molding is set to a dimension including a clearance provided between the pocket and the ball. 5. Method.   The said fiber reinforced thermoplastic resin is a manufacturing method of the corrugated cage of any one of Claim 1 thru | or 4 formed by filling a long fiber-like fiber discontinuously.

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