JP2018003872A - Manufacturing method of synthetic resin-made cage and synthetic resin-made cage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a synthetic resin-made cage which can enhance rigidity at a weld part, and the synthetic resin-made cage.SOLUTION: A synthetic resin-made cage 10 is formed by injecting molten resins G into a cavity 51 from a plurality of gates 52 which are formed at a peripheral edge of the substantially-annular cavity 51. A plurality of the gates 52 are arranged so that numbers of pockets 30 in inter-gate regions A1, A2 and A3 which adjoin one another in a peripheral direction become equal. Resin sumps 40 are arranged at one-side column parts 20 located at both sides out of the column parts 20 or the pockets 30 which are located at a center of the inter-gate regions A1, A2 and A3. Equivalent circle diameters of tips of a plurality of communication part 42 for making the column parts 20 and the resin sumps 40 communicate with each other are different from one another at each communication part 42, and not smaller than 0.5 mm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a synthetic resin cage and a synthetic resin cage, and more specifically, a method for manufacturing a synthetic resin cage formed by injection molding of a molten resin to which a reinforcing fiber material is added, and The present invention relates to a synthetic resin cage.

  Generally, the bearing cage is manufactured by injection molding. Specifically, an annular cavity corresponding to a bearing cage that is a molded body is formed in a molding die, and a resin material (thermoplastic resin) dissolved from a resin injection gate provided at the peripheral edge of the cavity It is manufactured by injecting and solidifying by cooling.

  The molten resin injected into the cavity flows into the cavity as two flows on both sides in the circumferential direction, and merges again at the position opposite to the resin injection gate in the radial direction. Is formed. In general, the resin cage for bearings thus molded by injection is only a fusion resin fused and integrated, so that the molten resin is not uniformly mixed, and the strength decreases at the weld. Is well known.

  In addition, when a reinforcing fiber material such as glass fiber, carbon fiber, or metal fiber is added as a reinforcing material to the molten resin, the reinforcing fiber material is oriented perpendicularly to the flow direction of the molten resin at the weld, so that the reinforcing effect Does not develop. Furthermore, since the reinforcing fiber material is oriented in parallel to the flow direction of the molten resin in the portion other than the weld portion, the difference in strength between the portion and the weld portion becomes large.

  In the method for manufacturing a synthetic resin cage described in Patent Document 1, in a molding die provided with a plurality of gates, the injected resin materials merge in the region having the longest circumferential distance among the regions between the gates. A resin reservoir is arranged corresponding to the location, and the injected resin material that has joined flows into the resin reservoir from the cavity, thereby improving the strength of the weld. In addition, the resin cage described in Patent Document 2 is a region between the gates where the number of pockets is an odd number, and one of the pillars formed at both ends of the pockets located at the circumferential center between the gates. A resin reservoir is provided in the column, and the strength of the weld is improved by pouring molten resin.

Japanese Patent No. 3666536 JP 2008-95770 A

However, in the manufacturing method described in Patent Document 1, a resin reservoir is provided at a joint location of the injected resin material, that is, a position that coincides with the weld formation position. Therefore, there is a problem that the reinforcing fiber material is easily oriented perpendicular to the flow direction of the resin material in the vicinity of the communication portion (opening) of the resin reservoir communicating with the cavity, and the weld reinforcement effect cannot be sufficiently obtained.
The resin cage of Patent Document 2 has an effect of improving the rigidity of the cage because the weld is formed at a position away from the bottom of the pocket in the circumferential direction, but the column portion and the resin reservoir are communicated with each other. The cross-sectional area at the tip of the communicating part has not been studied, and there was room for improvement in order to further improve the strength of the cage.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a synthetic resin cage manufacturing method and a synthetic resin cage that can increase the strength of the weld portion.

The above object of the present invention can be achieved by the following constitution.
(1) a substantially annular base portion, and a plurality of pillar portions that are arranged at predetermined intervals in the circumferential direction and project in the axial direction from one axial side surface of the base portion,
The same number of pockets as the pillars are defined by the mutually facing surfaces of the adjacent pillars and the one axial side surface of the base,
A synthetic resin cage in which a reinforcing fiber material is added to a synthetic resin,
The weld portion formed on the retainer is a synthetic resin retainer characterized in that a peripheral portion from the position of the outer surface of the weld toward the center portion is shifted in the circumferential direction and is formed in an uneven shape.
(2) a substantially annular base, and a plurality of pillars arranged in the circumferential direction at a predetermined interval and projecting in the axial direction from one axial side surface of the base,
The same number of pockets as the pillars are defined by the mutually facing surfaces of the adjacent pillars and the one axial side surface of the base,
A synthetic resin cage manufacturing method in which a reinforcing fiber material is added to a synthetic resin,
The cage is molded by injecting molten resin into the cavity from a plurality of gates provided at the peripheral edge of a substantially annular cavity formed in the molding die,
The plurality of gates are arranged so that the number of pockets in each inter-gate region adjacent in the circumferential direction is equal,
Resin pools are respectively provided in either of the pillars located in the center of each inter-gate region or the pillars located on both sides of the pockets.
At least one of the plurality of communicating portions that respectively communicate each of the column portions and each of the resin reservoirs is designed so that the equivalent circular diameter at the tip thereof is 0.5 mm or more. Manufacturing method of resin cage.
As in the present invention, when the molten resin flows, it is usual to construct a theoretical formula based on hydrodynamics. In other words, the equivalent circular diameter of the communication portion referred to here is the diameter of the circular cross section when the communication portion having an arbitrary cross-sectional shape (polygon) is replaced with a communication portion having a circular cross section that has an equivalent flow. , Defined by a value obtained by dividing four times the cross-sectional area of the communication portion by the circumference of the cross-section of the communication portion.

  According to the synthetic resin cage of the present invention, the weld portion formed on the cage is formed in an uneven shape while the peripheral portion from the position of the outer surface of the weld toward the center portion is shifted in the circumferential direction. The adhesion strength of the weld portion is improved by the unevenness, and the bonding strength of the weld portion is improved.

  Further, according to the method for manufacturing a synthetic resin cage of the present invention, the cage is formed by injecting molten resin into the cavity from a plurality of gates provided at the peripheral edge of the substantially annular cavity. . The plurality of gates are arranged so that the number of pockets in each inter-gate region adjacent to each other in the circumferential direction is equal, and the pillars located in the center of each inter-gate region or the pillars located on both sides of the pockets. A resin reservoir is provided in any one of the column portions. And since the equivalent circular diameter of the front-end | tip of the some communication part which each connects a pillar part and the resin reservoir differs for every communication part, after the front-end | tips of the molten resin injected in the cavity joined, each resin reservoir The inflow timing of the molten resin flowing into the resin differs for each resin reservoir. As a result, a complicated flow of the molten resin in the weld portion occurs, the weld line becomes uneven, and the weld strength of the weld portion is improved. Further, the orientation of the reinforcing fiber material in the weld portion is controlled in the flow direction of the molten resin, and the reinforcing effect of the weld portion by the reinforcing fiber material is enhanced. Moreover, since the equivalent circular diameter of the front-end | tip of a some communicating part is 0.5 mm or more, molten resin can be reliably made to flow into a resin pool irrespective of the size of a holder | retainer.

It is a perspective view of the synthetic resin cage injection-molded with the molding die concerning a 1st embodiment of the present invention. (A), (c), (e) is a schematic diagram which shows the behavior of the molten resin in the molding die of 1st Embodiment with time passage, (b), (d), (f) is ( It is the II section enlarged view of a), (c), (e). It is a perspective view of the annular test piece injection-molded with the side gate type molding die for experimentally obtaining the effect of the equivalent circular diameter at the tip of the communicating part that communicates the column part and the resin reservoir. FIG. 5 is a perspective view of a crown type cage that is injection-molded with a tunnel gate mold for experimentally determining the effect of the equivalent circular diameter at the tip of a communicating portion that communicates a column portion and a resin reservoir. (A), (c) is a schematic diagram which shows the behavior of the molten resin in the molding die of 2nd Embodiment which concerns on this invention with time passage, (b), (d) is (a), ( It is the V section enlarged view of c). (A), (c) is a schematic diagram which shows the behavior of the molten resin in the molding die of 3rd Embodiment which concerns on this invention with time, (b), (d) is (a), ( It is the VI section enlarged view of c).

  DESCRIPTION OF EMBODIMENTS Hereinafter, a method for producing a synthetic resin cage according to the present invention and embodiments of a synthetic resin cage produced by the method will be described in detail with reference to the drawings.

(First embodiment)
As shown in FIG. 1, a synthetic resin cage 10 (hereinafter also simply referred to as a cage) according to the present embodiment is a so-called crown-shaped cage, and has a substantially annular base 11 and a shaft of the base 11. And a plurality of column portions 20 (15 in the embodiment shown in the figure, but not limited to 15 in particular) projecting in the axial direction from the side end surface 12 in the circumferential direction at a predetermined interval. A plurality of embodiments (illustrated in the drawings) defined by the mutually facing surfaces 22 and 22 of the pair of column portions 20 and 20 and the axial one end side surface 12 of the base 11 to hold rolling elements (not shown) of the bearing. 15 pockets 30 are formed. That is, the number of the column parts 20 and the pockets 30 is the same, and the column parts 20 are provided on both sides in the circumferential direction of the respective pockets 30.

  The synthetic resin cage 10 of the present embodiment has three gates 52 (52A, 52B, 52C) in an annular cavity 51 formed in a molding die 50 via a substantially cylindrical sprue 55 and a runner 53. It is molded by injecting a molten resin G to which a reinforcing fiber material is added from a so-called three-point gate system, and cooling and solidifying it. In this embodiment, the gates 52A, 52B, and 52C have the same cross-sectional area.

  Examples of the resin material of the cage 10 include resins such as polyamide resins such as 46 nylon and 66 nylon, polybutylene terephthalate, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), and polyether nitrile (PEN). A resin composition to which 10 to 50 wt% of reinforcing fiber material F (for example, glass fiber or carbon fiber) is added is used.

  The three gates 52A, 52B, 52C are equally arranged in the circumferential direction so that the number of pockets 30 in each inter-gate region A1, A2, A3 is equal (five in the embodiment shown in the figure). Then, either one of the pillars 20 located on both sides of the pocket 30 located at the center of each inter-gate region A1, A2, A3 (in the embodiment shown in FIG. 1, in the clockwise direction of the pocket 30 located at the center). Three resin reservoirs 40 (40A, 40B, 40C) capable of storing the molten resin G are disposed at positions corresponding to adjacent column portions 20), that is, positions overlapping the column portions 20 in the circumferential direction. Yes. That is, each resin reservoir 40 is disposed at a position shifted in the circumferential direction from the center position of each inter-gate region A1, A2, A3. Resin reservoirs 40A, 40B, and 40C communicate with column portion 20 via communication portions 42A, 42B, and 42C, respectively.

  In the embodiment shown in the figure, since the number of column portions 20 is an odd number, the pocket 30 is located at the center of each inter-gate region A1, A2, A3. However, when the number of column portions 20 is an even number, the column portion 20 is located at the center of each inter-gate region A1, A2, A3. In this case, the resin reservoir 40 is disposed at a position corresponding to one of the column portions 20 on both sides of the column portion 20 located at the center.

  Each communication portion 42 (42A, 42B, 42C) that connects the column portion 20 and each resin reservoir 40 (40A, 40B, 40C) has a cross-sectional area of the communication portion 42 that is four times the cross-sectional area of the tip of the communication portion 42. Is equivalent circle diameter D, the equivalent circle diameter D at the tip of each communication portion 42 has a different value for each communication portion 42 and is 0.5 mm or more (D (Da , Db, Dc) ≧ 0.5 mm). The equivalent circular diameter D referred to here is D = 4 A / L = 4 m (equivalent circular diameter D, pipe cross-sectional area A based on the definition formula of the rectangular pipe flow (JSME text series, fluid dynamics, Maruzen, 2005). , Wetting length L, cross-sectional area m), the diameter of the circular cross section when the flow path having an arbitrary cross-sectional shape is replaced with a circular cross-section flow path equivalent to this.

  The equivalent circular diameters Da, Db, Dc of the communication portions 42A, 42B, 42C of the present embodiment are set to decrease in this order (Da> Db> Dc).

  The reason why the equivalent circular diameter D is different for each communication portion 42 is that the molten resin G flowing into the resin reservoir 40 after the molten resin G merges has different inflow timings for each communication portion 42, thereby melting the weld portion W. This is because the flow direction and speed of the resin G are controlled to make the shape of the weld portion W uneven, and the orientation of the reinforcing fiber material added to the molten resin G is also controlled.

  The reason why the equivalent circular diameter D is 0.5 mm or more is that if the cross-sectional area of the communication portion 42 that communicates the cavity 51 and the resin reservoir 40 is small, the molten resin G flows before the molten resin G flows into the resin reservoir 40. This is because the solidification of G starts, the forced molten resin G does not flow in the weld W, and the resin reservoir 40 may not work effectively.

  Here, in order to determine the minimum equivalent circular diameter D, as shown in FIGS. 3 and 4, a molding die having a resin reservoir 40 capable of molding the annular test piece 10A and the crown-shaped cage 10B is used. Produced and tested. The communication part 42 is a side gate type (FIG. 3) and a tunnel gate type (FIG. 4), and the state of the molten resin G flowing into the resin reservoir 40 when the dimensions of the communication part 42 are changed is determined by an injection molding experiment. confirmed.

Table 1 shows the experimental results. When the equivalent circular diameter D at the tip of the communicating portion 42 is less than 0.5 mm, the molten resin G hardly flows into the resin reservoir 40, whereas the equivalent circular diameter D is 0.5 mm. It can be seen that the molten resin G can flow into the resin reservoir 40 as described above. For this reason, the equivalent circular diameter D at the tip of the communication portion 42 is set to 0.5 mm or more.
In addition, test No. using a rectangular tube. The equivalent circular diameter D of 3 is obtained as follows.
Cross-sectional area A = 1.0 mm × 0.4 mm = 0.4 mm ²
Wetting length L = 2 × (1.0 mm + 0.4 mm) = 2.8 mm
Equivalent circle diameter D = 4 A / L = 4 × 0.4 mm ² /2.8 mm≈0.57 mm

  In addition, in order to start the inflow of the molten resin into the resin reservoir after the weld portion is formed, the cross-sectional area (equivalent circular diameter D) of the communication portion 42 of the resin reservoir 40 is 1 of the cross-sectional area of the gate. Designed to be / 4 or less. However, in the case of a molding die for a small-diameter retainer, when the cross-sectional area of the gate is small, the cross-sectional area of the tip of the communication portion 42 of the resin reservoir 40 is 0.5 mm or more regardless of the cross-sectional area of the gate. It is set.

  Next, the manufacturing method of the cage of this embodiment will be described. As shown in FIG. 2A, the molten resin G containing the reinforcing fiber material injected into the cavity 51 from each gate 52 (52A, 52B, 52C) through the sprue 55 and the runner 53 is contained in the cavity 51. It flows separately on both sides in the circumferential direction, and the tips thereof join at the center of each gate 52 to form a weld portion W.

  Here, the behavior of the molten resin G in the weld portion W after the end of the molten resin G is joined will be described by taking the weld portion W of the II portion in FIG. 2A as an example. As shown in FIG. 2A, after the molten resin G joins and the weld portion W is formed, the molten resin G flows into the resin reservoir 40A through the communication portion 42A having the largest equivalent circular diameter Da. To do. Therefore, a pressure gradient of the molten resin G is generated in the cavity 51 between the weld portion W and the resin reservoir 40A, and the molten resin G is caused in the direction of the resin reservoir 40A (clockwise) due to this pressure gradient. To flow. And in the weld part W, as shown in FIG.2 (b), the center part of one resin will be in the state which entered the other resin.

  When the inflow of the molten resin G to the resin reservoir 40A is completed, the molten resin G flows into the resin reservoir 40B through the communication portion 42B having the next largest equivalent circular diameter Db as shown in FIG. . Therefore, a pressure gradient of the molten resin G between the weld W and the resin reservoir 40B occurs in the cavity 51, and the molten resin G is caused in the direction of the resin reservoir 40B (clockwise) due to this pressure gradient. To flow. Then, as shown in FIG. 2D, in the weld portion W, the central portion of one resin is in a state of further entering the other resin.

  When the inflow of the molten resin G into the resin reservoir 40B is completed, the molten resin G flows into the resin reservoir 40C through the communication portion 42C having the smallest equivalent circular diameter Dc, as shown in FIG. To do. For this reason, a pressure gradient of the molten resin G is generated in the cavity 51 between the weld portion W and the resin reservoir 40C, and due to this pressure gradient, the molten resin G has a low flow resistance, in other words. The weld portion W and the resin reservoir 40C are short in distance and flow in the reverse direction (counterclockwise). Thus, as shown in FIG. 2 (f), in the weld portion W, the central portion of one resin is cooled and solidified in a state of entering the other resin, so that the synthetic resin cage 10 is formed.

  The inflow of the molten resin G into each resin reservoir 40 does not necessarily flow into the resin reservoir 40B after the resin reservoir 40A is filled, and does not flow into the resin reservoir 40C after the resin reservoir 40B is filled. The inflow into the resin reservoir 40 is started almost simultaneously. However, since the amount of inflow into each resin reservoir 40 is determined according to the equivalent circular diameters Da, Db, Dc at the tips of the communication portions 42A, 42B, 42C, the flow of the molten resin G is generally as described above.

  Due to the forced flow of the molten resin G in the weld portion W, the weld portion W has a circumferential portion Wa that moves from the position of the outer surface Wc of the weld portion W toward the central portion Wb in the circumferential direction, and the central portion. Wb is different from the tapered shape of the peripheral portion Wa, and has a tapered shape extending in the opposite direction to form an uneven shape, so that the strength in the weld portion W is improved. At the same time, the longitudinal direction of the reinforcing fiber material added to the molten resin G increases the ratio of the reinforcing fiber material F oriented in the circumferential direction, and the strength of the weld portion W is effectively increased by the reinforcing fiber material. To be strengthened. Thereby, the durability and reliability of the synthetic resin cage 10 are improved.

  As described above, according to the method for manufacturing a synthetic resin cage of the present embodiment, the synthetic resin cage 10 is made of molten resin from three gates 52 provided at the peripheral edge of the substantially annular cavity 51. It is formed by injecting G into the cavity 51. The three gates 52 are arranged so that the number of pockets 30 in each of the inter-gate regions A1, A2, A3 adjacent in the circumferential direction is equal, and the pockets located in the center of the inter-gate regions A1, A2, A3 Resin pools 40 are respectively provided in the column portions 20 adjacent to 30 in the counterclockwise direction. And since the equivalent circular diameter D of the front-end | tip of the some communication part 42 which each connects the pillar part 20 and the resin reservoir 40 differs for every communication part 42, the front-end | tips of the molten resin G inject | emitted in the cavity 51 are mutually. After joining, the inflow timing of the molten resin G flowing into the resin reservoir 40 is different for each resin reservoir 40. Thereby, a complicated flow of the molten resin G in the weld portion W occurs, the weld line becomes uneven, and the bonding strength of the weld portion W is improved. Moreover, the orientation of the reinforcing fiber material in the weld portion W is controlled, and the reinforcing effect of the weld portion W can be enhanced by the reinforcing fiber material. In addition, since the equivalent circular diameter D at the tips of the plurality of communicating portions 42 is 0.5 mm or more, the molten resin G can surely flow into the resin reservoir 40 regardless of the size of the cage 10.

  Further, according to the synthetic resin cage 10 of the present invention, the weld portion W formed in the cage 10 has a circumferential portion Wa that moves from the position of the outer surface Wc of the weld toward the center portion Wb in the circumferential direction. Since the central portion Wb is formed in an uneven shape having a shape different from the shape of the peripheral portion Wa, the adhesion strength of the weld portion W can be improved by the unevenness, and the bonding strength of the weld portion W can be improved.

(Second Embodiment)
Next, a synthetic resin cage according to a second embodiment will be described with reference to FIG. FIG. 5 is a schematic view showing the behavior of the molten resin in the molding die according to the second embodiment over time. The present embodiment is different from the first embodiment only in the size of the equivalent circular diameter D at the tip of the communication part 42 of the molding die, and the other parts are the molding die according to the first embodiment of the present invention. Since it is the same as the mold, the same parts are denoted by the same or corresponding reference numerals, and the description will be simplified or omitted.

  The equivalent circular diameter D at the tip of each communicating portion 42 of the synthetic resin cage 10 of the present embodiment has the largest equivalent circular diameter Da at the tip of the communicating portion 42A, and the equivalent circular diameter Db at the tip of the communicating portion 42B. The equivalent circular diameter Dc at the tip of the communication portion 42C is set to be smaller than the equivalent circular diameter Da and equal to each other (Da> Db = Dc).

  When the synthetic resin cage 10 of the present embodiment is molded, the molten resin G including the reinforcing fiber material injected into the cavity 51 from each gate 52 through the sprue 55 and the runner 53 is the tip of the molten resin G. After joining to form the weld portion W, as shown in FIG. 5A, it flows into the resin reservoir 40A via the communication portion 42A having the largest equivalent circular diameter Da.

  For this reason, a pressure gradient is generated in the molten resin G between the weld W and the resin reservoir 40A in the cavity 51, and the molten resin G flows in the direction of the resin reservoir 40A due to this pressure gradient. And in the weld part W, as shown in FIG.5 (b), the center part of one resin will be in the state which entered the other resin.

  When the inflow of the molten resin G into the resin reservoir 40A is completed, the molten resin G is connected to the communicating portions 42B having equivalent circular diameters Db and Dc of the next largest and equal size, as shown in FIG. It flows into the resin reservoirs 40B and 40C through 42C. At this time, since the flow of the molten resin G toward the communication portion 42B and the flow of the molten resin G toward the communication portion 42C are substantially balanced, the flow of the molten resin G in the weld portion W substantially stops. Thereby, as shown in FIG.5 (d), the joining surface shape of the molten resin G in the weld part W becomes complicated, and the intensity | strength of the weld part W improves.

  Therefore, the weld portion W formed in the retainer 10 has a peripheral portion Wa that moves from the position of the outer surface Wc of the weld portion W toward the central portion Wb in the circumferential direction, and the central portion Wb has a tapered shape of the peripheral portion Wa. It is formed in a concavo-convex shape with a substantially concave shape different from the above.

(Third embodiment)
Next, a synthetic resin cage according to a third embodiment will be described with reference to FIG. FIG. 6 is a schematic diagram showing the behavior of the molten resin in the molding die according to the third embodiment over time. Note that this embodiment also differs from the first embodiment only in the size of the equivalent circular diameter D at the tip of the communication portion 42 of the molding die, and the other parts are the molding die according to the first embodiment of the present invention. Since it is the same as the mold, the same parts are denoted by the same or corresponding reference numerals, and the description will be simplified or omitted.

  The equivalent circular diameter D at the tip of each communicating portion 42 of the synthetic resin retainer 10 of the present embodiment has the same size as the equivalent circular diameters Da and Db at the tips of the communicating portions 42A and 42B, and the communicating portion 42C. The equivalent circle diameter Dc of the tip of the is set smaller than the equivalent circle diameters Da and Db (Da = Db> Dc).

  When the synthetic resin cage 10 of the present embodiment is molded, the molten resin G including the reinforcing fiber material injected into the cavity 51 from each gate 52 through the sprue 55 and the runner 53 is the tip of the molten resin G. After joining and forming the weld part W, as shown to Fig.6 (a), it is simultaneous to resin reservoir 40A, 40B via communicating part 42A, 42B which has equivalent circular diameter Da, Db of the same magnitude | size. Inflow.

  For this reason, in the cavity 51, a pressure gradient is generated in the molten resin G between the weld portion W and the resin reservoirs 40A and 40B, and the molten resin G is converted into the resin reservoir 40A (resin reservoir 40B) due to the pressure gradient. ) Force to flow in the direction. The flow of the molten resin G is such that the communication portions 42A and 42B having the same equivalent circular diameters Da and Db are positioned in the same direction (clockwise in FIG. 6) with respect to the weld portion W. The process ends at a timing faster than the flow of the molten resin G in the first and second embodiments. Thereby, as shown in FIG.6 (b), in the weld part W, the center part of one resin will be in the state which entered the other resin.

  Then, when the inflow of the molten resin G into the resin reservoirs 40A and 40B is completed, the molten resin G passes through the communication portion 42C having the smallest equivalent circular diameter Dc, as shown in FIG. 6C. Flow into.

  For this reason, a pressure gradient is generated in the molten resin G between the weld W and the resin reservoir 40C in the cavity 51, and the molten resin G is caused in the resin reservoir 40C direction (counterclockwise) due to this pressure gradient. To flow. And as shown in FIG.6 (d), as for the weld part W formed in the holder | retainer 10, peripheral part Wa which goes to the center part Wb from the position of the outer surface Wc of this weld part W shifts | deviates to the circumferential direction, The central portion Wb is formed in a concavo-convex shape with a tapered shape extending in the opposite direction different from the tapered shape of the peripheral portion Wa. Thereby, the shape of the joint surface of the molten resin G in the weld portion W becomes complicated, and the strength of the weld portion W is improved.

Note that the present invention is not limited to the above-described embodiments and examples, and modifications, improvements, and the like can be made as appropriate.
For example, the communication portion 42 may have a tapered shape whose diameter increases toward the resin reservoir 40 as in the present embodiment, but the present invention is not limited to this, and the communication portion 42 has a uniform shape in the longitudinal direction. May be. In addition, the equivalent circular diameter D at the tip of the tapered communication portion 42 of the present invention indicates a position where the cross-sectional area is minimum.

DESCRIPTION OF SYMBOLS 10 Synthetic resin cage | basket 11 Base 12 One axial direction side surface 20 Column part 22 The mutually opposing surface 30 Pocket 40, 40A, 40B, 40C Resin reservoir 42, 42A, 42B, 42C Communication part 50 Mold 51 Cavity 52, 52A, 52B, 52C Gate A1, A2, A3 Intergate region D, Da, Db, Dc Equivalent circular diameter G Molten resin W Weld part

Claims (2)

A substantially annular base, and a plurality of pillars that are arranged at predetermined intervals in the circumferential direction and project in the axial direction from one axial side surface of the base,
The same number of pockets as the pillars are defined by the mutually facing surfaces of the adjacent pillars and the one axial side surface of the base,
A synthetic resin cage in which a reinforcing fiber material is added to a synthetic resin,
The weld portion formed on the retainer is a synthetic resin retainer characterized in that a peripheral portion from the position of the outer surface of the weld toward the center portion is shifted in the circumferential direction and is formed in an uneven shape. A substantially annular base, and a plurality of pillars that are arranged at predetermined intervals in the circumferential direction and project in the axial direction from one axial side surface of the base,
The same number of pockets as the pillars are defined by the mutually facing surfaces of the adjacent pillars and the one axial side surface of the base,
A synthetic resin cage manufacturing method in which a reinforcing fiber material is added to a synthetic resin,
The cage is molded by injecting molten resin into the cavity from a plurality of gates provided at the peripheral edge of a substantially annular cavity formed in the molding die,
The plurality of gates are arranged so that the number of pockets in each inter-gate region adjacent in the circumferential direction is equal,
Resin pools are respectively provided in either of the pillars located in the center of each inter-gate region or the pillars located on both sides of the pockets.
At least one of the plurality of communicating portions that respectively communicate each of the column portions and each of the resin reservoirs is designed so that the equivalent circular diameter at the tip thereof is 0.5 mm or more. Manufacturing method of resin cage.