JP2019126959A - Manufacturing method of bearing retainer - Google Patents

Abstract

To provide a bearing retainer manufacturing method capable of improving weld strength by causing molten resin to flow in the weld.SOLUTION: Of a plurality of column part 20, half of the column part 20 are each provided with a resin injection gate 51, and the column part 20 provided with the resin injection gate 51 and the column part 20 spaced apart from the resin injection gate 51 in the circumferential direction are alternately arranged in the circumferential direction, and among the plurality of resin injection gates 51, between a resin injection gate 51 and the two resin injection gate 51 that is farthest from the resin injection gate 51 toward both sides in the circumferential direction, a resin reservoir 41, 42 that can store a molten resin by flowing molten resin from a cavity Ca are provided respectively, and a relative difference is provided in a cross-sectional areas of a communication passage 41a, 42a that communicates with the cavity Ca of the two resin reservoir 41, 42.SELECTED DRAWING: Figure 2

Description

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

  As a conventional manufacturing method of a bearing cage, it is molded by injecting molten resin into a cavity from a plurality of resin injection gates provided on the peripheral portion of a substantially annular cavity formed in a molding die. A manufacturing method of a bearing cage, wherein the bearing cage comprises a base having a substantially annular shape, and a plurality of even number of pillars axially projecting at predetermined intervals in a circumferential direction from one side surface of the base in the axial direction. And a number of pockets equal to the number of pillars formed by the mutually opposing surfaces of a pair of adjacent pillars and the axial end face of the base, and half of the plurality of pillars are pillars In each of the plurality of resin injection gates, a resin injection gate is provided, and a pillar portion provided with the resin injection gate and a pillar portion not provided with the resin injection gate are alternately arranged in the circumferential direction. The cross-sectional area of one resin injection gate is the other Among a plurality of pillars larger than the cross sectional area of the resin injection gate and not provided with the resin injection gate, radially opposed to the pillar provided with the resin injection gate larger in cross sectional area than the other resin injection gates A resin reservoir capable of storing molten resin is provided in the column portion or in the column portion in the vicinity of the opposing column portion, and the cross-sectional area of the communicating portion (opening) of the resin reservoir communicating with the column portion is It is known to make the cross-sectional area of a plurality of resin injection gates smaller than the smallest one (see, for example, Patent Document 1).

JP, 2016-114100, A

  However, in the method of manufacturing the bearing cage described in Patent Document 1, the cross-sectional area of the resin reservoir communication portion is smaller than that of the resin injection gate, which is the smallest cross-sectional area, When the cross-sectional area of the resin injection gate is small, such as molding the cage, the cross-sectional area of the communicating portion of the resin reservoir may be excessively reduced. As a result, the molten resin solidifies in the communicating portion of the resin reservoir before the molten resin flows into the resin reservoir, so that the resin reservoir function can not be exhibited, and forced resin flow in the weld occurs. It did not occur, and the orientation of the reinforcing fiber material could not be controlled.

  The present invention has been made in view of the above-mentioned problems, and its object is to improve the strength of welds by causing the flow of molten resin in welds without being affected by the size of the resin injection gate. An object of the present invention is to provide a method for manufacturing a bearing retainer that can be used.

The above object of the present invention is achieved by the following constitution.
(1) A manufacturing method of a bearing cage formed by injecting molten resin into the cavity from a plurality of resin injection gates provided on the peripheral portion of an annular cavity formed in a molding die The bearing cage includes a pair of even and even number of pillars axially projecting at predetermined intervals in a circumferential direction from a substantially annular base, one end side surface of the base in the axial direction, and a pair And the number of pockets equal to the number of the pillars formed by the mutually facing surfaces of the pillars and the side surfaces of the base in the axial direction, and half of the plurality of pillars The resin injection gate is provided, and the pillars provided with the resin injection gate and the pillars spaced apart from the resin injection gate in the circumferential direction are alternately disposed in the circumferential direction, Of the resin injection gate Molten resin flows from the cavity between the one resin injection gate and the two resin injection gates farthest from the one resin injection gate in the circumferential direction. Reservable resin reservoirs are respectively provided, and the two resin reservoirs have communication paths respectively communicating with the cavity, and a relative difference is provided in the cross-sectional area of the communication paths of the two resin reservoirs. A method for manufacturing a bearing cage.
(2) The method for manufacturing a bearing cage according to (1), wherein the two resin reservoirs are disposed symmetrically in the circumferential direction with respect to the resin injection gate having a large cross-sectional area.
(3) The method for manufacturing a bearing cage according to (1) or (2), wherein the resin reservoir is disposed at a circumferential intermediate position between the adjacent resin injection gates.
(4) The two resin reservoirs are respectively disposed between the resin injection gate having a large cross-sectional area and the resin injection gate adjacent on both sides in the circumferential direction from the resin injection gate having a large cross-sectional area. The method for manufacturing a bearing retainer according to any one of (1) to (3).

  According to the present invention, a cavity is formed between one resin injection gate and the two resin injection gates farthest from the one resin injection gate in the circumferential direction among the plurality of resin injection gates. The molten resin flows in from there and resin reservoirs capable of storing the molten resin are respectively provided, and a relative difference is provided between the cross-sectional areas of the communication paths of the two resin reservoirs, so the resin injection gate size is not affected. The strength of the weld can be improved by causing the molten resin to flow in the weld.

It is a perspective view of the cage for bearings manufactured by one embodiment of the manufacturing method concerning the present invention. It is the top view which looked at the cage for bearings shown in Drawing 1 from the pillar side. It is a schematic diagram explaining the state which a large amount of molten resin flows on the 1st resin reservoir side in resin inflow area | region B of FIG. FIG. 3 is a schematic view illustrating a state in which a large amount of molten resin flows on a first resin reservoir side in a resin inflow region C of FIG. 2; It is a schematic diagram explaining the state which molten resin flows toward a 1st resin reservoir in weld formation area A of FIG. FIG. 3 is a schematic view for explaining a state in which a large amount of molten resin flows on a second resin reservoir side in a resin inflow region B of FIG. 2; FIG. 3 is a schematic view illustrating a state in which a large amount of molten resin flows on a second resin reservoir side in a resin inflow region C of FIG. 2; It is a schematic diagram explaining the state which molten resin flows toward a 2nd resin reservoir in weld formation area A of FIG. (A) is a schematic diagram explaining the solidification state of molten resin when molten resin flows toward the 1st resin accumulation in weld formation area A, (b) is shown in the 2nd resin accumulation in weld formation area A. It is a schematic diagram explaining the solidified state of molten resin when molten resin flows toward it. It is a top view of the holder for bearings manufactured by the modification of one embodiment of the manufacturing method concerning the present invention. It is a top view of the holder for bearings for explaining the comparative example where the resin reservoir is arranged in the position different from the present invention.

  Hereinafter, one embodiment of a manufacturing method of a holder for bearings concerning the present invention is described in detail based on a drawing.

  In FIG. 1 and FIG. 2, the cage for bearings of the present embodiment (hereinafter, also simply referred to as a cage) 1 is provided with runners 53, sprues 55, and first and second resin reservoirs 41 and 42 described later. It is shown in the The cage 1 is a so-called crown-shaped cage, and a plurality and even number axially projecting from the substantially annular base 10 and one end side 12 of the base 10 in the axial direction at predetermined intervals in the circumferential direction (this embodiment And the opposed surfaces 22, 22 of a pair of adjacent pillars 20, 20 and one axial end side 12 of the base 10, and the rolling elements (not shown) of the bearing And a plurality (even in this embodiment) of pockets 30 to be held. That is, the number of the column parts 20 and the pockets 30 is the same, and a plurality of and even numbers are formed, and the column parts 20 are provided on both sides in the circumferential direction of the respective pockets 30.

  In such a manufacturing method of the cage 1, multipoint gate type injection molding is employed. Specifically, the cage 1 includes a plurality of resin injection gates (described below) provided on the inner peripheral edge of an annular cavity Ca (see FIG. 3) formed in the molding die 60 (see FIG. 3). , Simply referred to as a gate.) From 51, the molten resin to which the reinforcing fiber material is added is injected into the cavity Ca and molded by cooling and solidifying. The resin material is, for example, a polyamide resin such as 46 nylon or 66 nylon, a resin such as polybutylene terephthalate, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyether nitrile (PEN), etc. % Of a reinforcing fiber material (for example, glass fiber or carbon fiber) is used. In FIG. 1 and FIG. 2, the cavity Ca is not shown, but its internal structure is substantially the same as the structure of the cage 1.

  The molten resin is supplied from the substantially cylindrical sprue 55 to the respective gates 51 via the substantially cylindrical runners 53 extending in the radial direction. The sprue 55 extends in the axial direction substantially at the center of the holder 1 (cavity) and is connected to the runner 53. Therefore, the molten resin supplied from the sprue 55 reaches the gates 51 via the runners 53, and flows from the gates 51 simultaneously into the cavity.

  A gate 51 is provided in each half (7 in the present embodiment) of the plurality of pillars 20. Each gate 51 communicates with the central portion in the circumferential direction of the inner peripheral surface of the column portion 20 (cavity). The pillars 20 on which the gate 51 is provided and the pillars 20 spaced from the gate 51 in the circumferential direction are alternately arranged in the circumferential direction. Thus, by arranging a large number of gates 51 at equal intervals, it is possible to suppress the collapse of the roundness of the cage 1 and realize high-accuracy rotation of the bearing. Here, among the plurality (seven) of gates 51, the cross-sectional area of one gate 51 (hereinafter may be referred to as a large diameter gate 51a) is referred to as another gate 51 (hereinafter referred to as a small diameter gate 51b). In some cases). In the present embodiment, the large diameter gate 51 a is the “one resin injection gate” according to claim 1.

  The first resin reservoir 41 and the second resin, in which the molten resin flows from the cavity Ca into the two pillars 20 among the plurality of pillars 20 circumferentially spaced from the gate 51, can store the molten resin. A reservoir 42 is provided. The first resin reservoir 41 and the second resin reservoir 42 are respectively separated between the large diameter gate 51a having a large cross sectional area and the two small diameter gates 51b farthest from the large diameter gate 51a in the circumferential direction. Provided. That is, the first resin reservoir 41 and the second resin reservoir 42 are respectively disposed in the range of the angle θ (see FIG. 2) from the large diameter gate 51a to the two small diameter gates 51b farthest from the large diameter gate 51a in the circumferential direction. . In the present embodiment, the first resin reservoir 41 and the second resin reservoir 42 are disposed on the column portion 20 adjacent to the two farthest small-diameter gates 51b.

  The first resin reservoir 41 and the second resin reservoir 42 have a communication passage 41a and a communication passage 42a communicating with the column portion 20 (cavity Ca), and the cross-sectional areas of the communication passages 41a and 42a have a relative difference. ing. In the present embodiment, the cross sectional area of the communication passage 41a is formed larger than the cross sectional area of the communication passage 42a. The relative difference in cross-sectional area between the communication passages 41a and 42a is preferably 0.5 mm or more in terms of the equivalent circular diameter.

  Further, the first resin reservoir 41 and the second resin reservoir 42 are disposed symmetrically in the circumferential direction with respect to the large diameter gate 51a having a large cross sectional area. The first resin reservoir 41 and the second resin reservoir 42 are disposed at circumferentially intermediate positions between the adjacent gates 51. That is, the first resin reservoir 41 and the second resin reservoir 42 are disposed at the intermediate position in the circumferential direction of the column portion 20 that is separated from the gate 51 in the circumferential direction.

  In the molding die 60 configured in this manner, the molten resin injected from each gate 51 into the cavity Ca flows on both sides in the circumferential direction of each gate 51 and merges between the adjacent gates 51. Specifically, between the small diameter gates 51b, the molten resin merges at a circumferentially intermediate position between the small diameter gates 51b, and a weld W is formed at a circumferentially intermediate portion of the pillar portion 20. On the other hand, between the large diameter gate 51a and the small diameter gate 51b, the molten resin merges at a position shifted to the small diameter gate 51b side from the circumferential direction middle position of these, and the diameter is smaller than the circumferential direction middle portion of the column 20 A weld W is formed at a position shifted to the gate 51b side. This is because the inflow of molten resin from the large diameter gate 51a is larger than the inflow of the small diameter gate 51b.

  Next, a second resin having a weld forming area A (see FIG. 2) around weld W formed at a position radially opposed to large diameter gate 51a, and a communication passage 42a having a small cross section with weld forming area A The resin inflow region B (see FIG. 2) around the pillar portion 20 between the reservoir 42 and the pillar portion 20 between the weld formation region A and the first resin reservoir 41 having the communication passage 41a having a large cross-sectional area The flow of the molten resin after the molten resin injected from the gate 51 into the cavity merges in the peripheral resin inflow region C (see FIG. 2) will be described.

  First, in the resin inflow area B, as shown in FIG. 3, the molten resin which has flowed (f1) from the small diameter gate 51b into the cavity Ca branches to both sides in the circumferential direction in the cavity Ca, and the first resin reservoir 41 side And a branch flow f3 flowing to the second resin reservoir 42 side. Then, since the molten resin is first filled from the first resin reservoir 41 having the communication passage 41a having a large cross-sectional area, the flow velocity of the branch flow f2 becomes larger than the flow velocity of the branch flow f3 (flow velocity: f2> f3).

  Next, in the resin inflow area C, as shown in FIG. 4, the molten resin that has flowed into the cavity Ca (f 1) from the small diameter gate 51 b is branched to both sides in the circumferential direction in the cavity Ca, and the first resin reservoir 41 A branch flow f4 flowing to the side and a branch flow f5 flowing to the second resin reservoir 42 side. Then, since the molten resin is first filled from the first resin reservoir 41 having the communication passage 41a having a large cross-sectional area, the flow velocity of the branch flow f4 becomes larger than the flow velocity of the branch flow f5 (flow velocity: f4> f5).

  As a result, as shown in FIG. 5, the branch flow f2 having a high flow velocity and the branch flow f5 having a low flow velocity join in the weld forming region A, and the molten resin flows toward the first resin reservoir 41. Is formed in a shape protruding in a substantially V shape on the first resin reservoir 41 side. The shape of the weld W projecting in a substantially V shape is such that the flow velocity of the molten resin flowing in the vicinity of the inner surface of the cavity is greater than the flow velocity of the molten resin flowing in the central portion of the cavity. Because it is too late.

  Next, after the first resin reservoir 41 is filled with the molten resin to some extent, the second resin reservoir 42 starts to be filled with the molten resin. Therefore, in the resin inflow region B, as shown in FIG. Becomes larger than the flow velocity of the branch flow f2 (flow velocity: f3> f2), and as shown in FIG. 7, the flow velocity of the branch flow f5 becomes larger than the flow velocity of the branch flow f4 in the resin inflow region C (flow velocity: f5 > F4).

  As a result, as shown in FIG. 8, in the weld formation region A, the flow velocity of the branched flow f5 flowing toward the second resin reservoir 42 gradually increases, and the flow velocity of the branched flow f2 flowing toward the first resin reservoir 41 gradually And the molten resin flows toward the second resin reservoir 42, so that the center of the cavity of the weld W formed in such a shape as to project substantially V-shaped toward the first resin reservoir 41 in the stage of FIG. The portion is formed in a shape that protrudes in a substantially V shape on the second resin reservoir 42 side. That is, the weld W is formed in a substantially W shape. Thereby, since the shape of the weld W becomes complicated, the orientation of the reinforcing fiber material, which was once oriented perpendicular (radial direction) to the flow direction (circumferential direction) at the time of joining the molten resins, is controlled, and the strength of the weld W is Can be improved.

  Subsequently, the formation of the weld W will be further described. As shown in FIGS. 9A and 9B, after the first resin reservoir 41 having the communication passage 41a having a large cross-sectional area is filled with the molten resin, The molten resin flow C changes in the opposite direction, and the molten resin flows toward the second resin reservoir 42. At this time, since the molten resin is solidified on the wall surface of the cavity Ca as time passes (symbol Fp in FIG. 9), the space of the cavity Ca becomes smaller. For this reason, after the first resin reservoir 41 is filled with the molten resin, the flow velocity of the molten resin is increased. As a result, as shown in FIG. 9B, the molten resin on the first resin reservoir 41 side where the flow velocity is increased bites deeply into the molten resin on the second resin reservoir 42 side, so the strength of the weld W is improved.

  As described above, the formation of the weld W in the weld formation region A shown in FIG. 2 has been described, but the same flow of molten resin occurs in the weld W at other positions, and all the welds W are formed in a substantially W shape. . Accordingly, since the strength of all the welds W is improved, the strength of the cage 1 can be improved.

  As described above, according to the manufacturing method of the bearing cage of the present embodiment, one resin injection gate 51a and the two resin injection gates 51a farthest from the one resin injection gate 51a in the circumferential direction Between the resin injection gate 51b and the resin injection gate 51b, molten resin flows from the cavity Ca and resin reservoirs 41 and 42 capable of storing the molten resin are respectively provided, and the cross-sectional areas of the communication paths 41a and 42a of the two resin reservoirs 41 and 42 are provided. Therefore, the strength of the weld W can be improved by causing the molten resin to flow in the weld W without being affected by the size of the resin injection gate 51. Therefore, the strength of the cage 1 can be improved. In addition, since the cross-sectional areas of the communication paths 41a and 42a are set without being affected by the size of the resin injection gate 51, the cross-sectional area of the resin injection gate is small (for example, when forming a small diameter cage) In this case, the molten resin can flow in the weld W, and the strength of the weld W can be improved. In addition, since the capacity of the resin reservoir can be reduced, the material cost of the molten resin can be suppressed.

  Further, according to the manufacturing method of the bearing cage of the present embodiment, after the first resin reservoir 41 having the communication passage 41a having a large cross-sectional area is filled with the molten resin, the flow C of the molten resin changes in the opposite direction The molten resin flows toward the second resin reservoir 42. At this time, since the molten resin is solidified on the wall surface of the cavity Ca as time passes, the space of the cavity Ca becomes smaller. For this reason, after the first resin reservoir 41 is filled with the molten resin, the flow velocity of the molten resin is increased. As a result, the molten resin on the first resin reservoir 41 side where the flow velocity has increased deeply penetrates into the molten resin on the second resin reservoir 42 side, so that the strength of the weld W can be improved.

  Further, according to the manufacturing method of the bearing cage of the present embodiment, since the two resin reservoirs 41 and 42 are arranged symmetrically in the circumferential direction with respect to one certain resin injection gate 51a, each weld W Can be made uniform.

  Further, according to the manufacturing method of the bearing cage of the present embodiment, since the first resin reservoir 41 and the second resin reservoir 42 are disposed at the circumferential intermediate position between the adjacent gates 51, each weld W Can be made uniform.

  Next, as a modified example of the present embodiment, as shown in FIG. 10, the first resin reservoir 41 and the second resin reservoir 42 are large diameter gates 51a having a large cross sectional area and both sides in the circumferential direction from the large diameter gates 51a. May be disposed between the adjacent small-diameter gates 51b. According to this modified example, the adjustment of the flow rate of the molten resin can be easily controlled, the shape of each weld W (the substantially W shape) is uniform, and the strength of each weld W can be made uniform.

  Next, with reference to FIG. 11, a comparative example in which the arrangement of the first resin reservoir 41 and the second resin reservoir 42 is changed will be described. In this comparative example, the first resin reservoir 41 and the second resin reservoir 42 are disposed between the two small diameter gates 51b farthest from the large diameter gate 51a toward both sides in the circumferential direction. In this case, since the flow of the molten resin as shown in FIGS. 5 and 8 does not occur, the strength improvement effect of the weld W can not be obtained.

The present invention is not limited to the ones exemplified in the above embodiments, and can be appropriately modified without departing from the scope of the present invention.
For example, the present invention is not limited to the above-described coronary cage, but is applicable to various types of cages such as a comb cage.
The plurality of resin injection gates may all be set to the same cross-sectional area.

  Moreover, since the cage for bearings of the present invention is high in strength and excellent in durability, it is suitable to be applied to a rolling bearing. That is, such a rolling bearing holds the inner ring, the outer ring, the plurality of rolling elements provided between the inner ring and the outer ring, and the plurality of rolling elements in the pocket in a freely rolling manner, and is excellent in durability. And the cage, it is possible to satisfy requirements such as high-speed rotation and high load.

DESCRIPTION OF SYMBOLS 1 Bearing cage 10 Base 12 One axial end side of base 12 Side of column 22 Column 22 opposite surface 30 Pocket 41 First resin reservoir 41a Communication passage 42 Second resin reservoir 42a Communication passage 51 Resin injection gate 51a Large diameter gate (Resin injection gate, one resin injection gate)
51b Small-diameter gate (resin injection gate)
53 Runner
55 Sprue 60 Mold Mold Ca Cavity W Weld

Claims (4)

A manufacturing method of a bearing cage formed by injecting a molten resin into the cavity from a plurality of resin injection gates provided on the peripheral portion of an annular cavity formed in a molding die,
The bearing cage is
A substantially annular base;
A plurality of and even number of pillars projecting in the axial direction at predetermined intervals in the circumferential direction from one axial side surface of the base; and
The same number of pockets as the pillars formed by the mutually opposing surfaces of a pair of adjacent pillars and the axial one end side surface of the base;
Have
Of the plurality of column portions, half of the column portions are each provided with the resin injection gate,
The column portions provided with the resin injection gate and the column portions spaced apart from the resin injection gate in the circumferential direction are alternately arranged in the circumferential direction,
From a plurality of the resin injection gates, between the one resin injection gate and the two resin injection gates farthest from the one resin injection gate in the circumferential direction, from the cavity Each of the resin reservoirs capable of storing molten resin flowing in and storing molten resin is provided,
Each of the two resin reservoirs has a communication path communicating with the cavity,
A manufacturing method of a bearing cage, wherein a relative difference is provided in a cross-sectional area of the communication path of the two resin reservoirs. The method for manufacturing a bearing cage according to claim 1, wherein the two resin reservoirs are arranged symmetrically in the circumferential direction with respect to the resin injection gate having a large cross-sectional area. The method for manufacturing a bearing cage according to claim 1 or 2, wherein the resin reservoir is disposed at a circumferential intermediate position between the adjacent resin injection gates. The two resin reservoirs are respectively disposed between the resin injection gate having a large cross-sectional area and the resin injection gate adjacent on both sides in the circumferential direction from the resin injection gate having a large cross-sectional area. The manufacturing method of the cage for bearings of any one of Claims 1-3 to do.

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