Cage, rolling bearing, and cage molding method

Abstract

A retainer (14) made of synthetic resin is provided with: an annular body (17); a plurality of angular portions (19); a plurality of gate marks (28) formed at intervals in the circumferential direction; welding parts (24) formed between the gate marks (28) adjacent to each other in the circumferential direction; and a plurality of pocket-forming sections (21) that are disposed between the gate marks (28), respectively, and that form pockets (15). Each pocket-forming section (21) has a through-hole (23) formed so as to penetrate in the axial direction at the bottom of the pocket (15). The welded section (24) is formed between the gate marks (28) only in a region (R1) on one side in the circumferential direction than the through-hole (23) or in a region (R2) on the other side in the circumferential direction than the through-hole (23).

Description

Technical Field

[0001] The invention relates to a cage, a rolling bearing and a method for forming the cage. Background Art

[0002] For example, rolling bearings used in drive units such as automobile transmissions are required to reduce the axial width of rolling bearings as the drive units are miniaturized. When the retainer that holds the rolling body extends axially beyond the sides of the outer ring and the inner ring by reducing the width of the rolling bearing, the retainer may interfere with other components other than the rolling bearing during the manufacturing process, packaging, or transportation of the rolling bearing, and the retainer may be damaged. Therefore, when reducing the width of the rolling bearing, the retainer needs to not extend axially relative to the sides of the outer ring and the inner ring. Therefore, it is considered to use a crown retainer made of synthetic resin (for example, refer to Patent Document 1) to reduce the width of the rolling bearing.

[0003] Fig.10 It is a perspective view showing a part of a conventional crown-shaped retainer 90 made of synthetic resin. Fig.11 is a cross-sectional view of a rolling bearing 80 having a crown-shaped retainer 90. Fig.10 and Fig.11 As shown, the crown retainer 90 has an annular body 91 and a plurality of angular portions 92. The annular body 91 is annular. The annular body 91 is arranged on one axial side between the outer ring 81 and the inner ring 82. The plurality of angular portions 92 protrude from the annular body 91 to the other axial side. The pocket 93 is a space surrounded by two adjacent angular portions 92 and the annular body 91 between the two angular portions 92. The rolling element 83 is accommodated in the pocket 93. The crown retainer 90 makes the axial thickness t11 of the bottom 91a of the pocket 93 of the annular body 91 thinner. Since the thickness t11 is thin, the axial width dimension W11 of the rolling bearing 80 is smaller than that of a rolling bearing of a standard size.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-127974 Summary of the invention

[0007] Problems to be solved by the invention

[0008] As described above, by reducing the thickness t11 of the bottom 91a of the annular body 91 of the crown-shaped retainer 90, the axial width dimension W11 of the rolling bearing can be reduced. On the other hand, since the thickness t11 is thin, the strength of the crown-shaped retainer 90 is lower than that of a standard-sized rolling bearing. Therefore, there is a limit to reducing the thickness of the bottom 91a of the annular body 91.

[0009] The present invention can ensure the strength of the cage and reduce the axial width dimension of the rolling bearing as much as possible.

[0010] Means for solving problems

[0011] The retaining frame of the present invention is made of synthetic resin, and comprises an annular body and a plurality of angular portions, and a plurality of pockets are formed between the angular portions adjacent to each other in the circumferential direction, the plurality of angular portions protrude from the annular body to one side axially at intervals in the circumferential direction of the annular body, and the pockets retain the plurality of rolling elements of the rolling bearing so that they can roll freely, wherein the retaining frame comprises: a plurality of gate marks formed at intervals in the circumferential direction; a welding portion formed between the gate marks adjacent to each other in the circumferential direction; and a plurality of pocket forming portions, respectively arranged between the gate marks to form each of the pockets, each of the pocket forming portions having a through hole formed axially through the bottom of the pocket, and the welding portion is formed between the gate marks only in an area on one side of the circumferential direction than the through hole or only in an area on the other side of the circumferential direction than the through hole.

[0012] The rolling bearing of the present invention includes: an inner ring; an outer ring; a plurality of rolling elements arranged between the inner ring and the outer ring; and the retainer.

[0013] The molding method of the retainer of the present invention is a method of molding the retainer by a mold, wherein the mold has a plurality of runners, a plurality of gates connected to each of the runners, and an annular cavity, wherein the cavity is connected to the plurality of gates at intervals in the circumferential direction, wherein in the cavity, a plurality of pocket molding spaces for molding each of the pocket forming portions and a plurality of angled portion molding spaces for molding each of the angled portion forming portions are alternately formed in the circumferential direction, and one of the gates is connected to each of the angled portion molding spaces, and when molten resin flows into the cavity from each of the runners via the gates, the volume of molten resin flowing from one of the two circumferentially adjacent gates is made greater than the volume of molten resin flowing from the other gate.

[0014] Effects of the Invention

[0015] According to the present invention, the axial width dimension of the rolling bearing can be reduced as much as possible while ensuring the strength of the cage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional view of a rolling bearing according to an embodiment of the present invention.

[0017] Figure 2 It is a perspective view showing a cage of a rolling bearing.

[0018] Figure 3 It is a perspective view showing an annular member of the retainer.

[0019] Figure 4 yes Figure 2 Sectional view taken along arrow II.

[0020] Figure 5 This is a front view of the annular member as viewed from the axial inner side.

[0021] Figure 6 It is a perspective view showing a part of the annular member.

[0022] Figure 7 This is a diagram showing a portion of a pair of annular members exploded as viewed from the radially inner side.

[0023] Figure 8 It is a perspective view showing a mold for molding the annular member by injection molding.

[0024] Fig. 9 It is a top view of the mold.

[0025] Fig.10 This is a perspective view showing a part of a conventional crown-shaped cage made of synthetic resin.

[0026] Fig.11 This is a cross-sectional view of a rolling bearing having a conventional crown-shaped cage. DETAILED DESCRIPTION

[0027] First, the contents of the embodiment will be listed and described.

[0028] <Overview of Embodiment>

[0029] (1) A retainer in an embodiment is made of synthetic resin, and comprises an annular body and a plurality of angular portions, wherein a plurality of pockets are formed between the angular portions adjacent to each other in the circumferential direction, the plurality of angular portions protruding from the annular body to one side in the axial direction at intervals in the circumferential direction of the annular body, and the pockets retain a plurality of rolling elements of the rolling bearing so that they can roll freely, wherein the retainer comprises: a plurality of gate marks formed at intervals in the circumferential direction; a weld portion formed between the gate marks adjacent to each other in the circumferential direction; and a plurality of pocket forming portions respectively arranged between the gate marks to form each of the pockets, each of the pocket forming portions having a through hole formed axially through the bottom of the pocket, the weld portion being formed between the gate marks only in an area on one side of the circumferential direction than the through hole or only in an area on the other side of the circumferential direction than the through hole.

[0030] According to the above retainer, since a through hole is formed at the bottom of the pocket in the pocket forming portion, the axial thickness of the bottom of the pocket forming portion can be reduced as much as possible. As a result, the axial width dimension of the rolling bearing can be reduced. In addition, between the gate marks adjacent to each other in the circumferential direction, a weld is formed only in the area on one circumferential side or the other circumferential side of the through hole. As a result, the formation of the weakest weld in the area (stress concentration area) radially outside and radially inside the through hole in the pocket forming portion during use of the rolling bearing can be suppressed. Therefore, even if a through hole is formed in the pocket forming portion, the strength of the retainer can be ensured.

[0031] (2) In the retaining frame described in (1) above, preferably, the weld portion comprises: a first weld portion extending in the entire radial direction when viewed in the axial direction; and a second weld portion extending in the circumferential direction from a radial midway position of the first weld portion to the through hole when viewed in the axial direction.

[0032] In this case, the strength of the cage can be further improved compared to a case where only the second weld portion is formed to extend in the entire circumferential direction in a region on one circumferential side or the other circumferential side relative to the through hole.

[0033] (3) The retainer described in (2) above preferably further includes a plurality of angled portion forming parts, wherein the plurality of angled portion forming parts form the angled portions, and one gate mark is formed in each of all the angled portion forming parts.

[0034] In this case, when the retainer is molded by the mold, the molten resin flows into the mold from the gates corresponding to all the angled portion forming portions. Therefore, by controlling the volume of the molten resin flowing from each gate, the first welded portion and the second welded portion can be easily formed in the region closer to one side or the other side of the through hole in the circumferential direction.

[0035] (4) In the retainer described in any one of (1) to (3) above, it is preferable that a pair of annular members including the annular body and the plurality of angular portions are connected in the axial direction.

[0036] In this case, since the retainer is composed of a pair of annular members, the strength of the retainer can be further improved compared to a case where the retainer is composed of only a single annular member and has columns formed by connecting the angular portions of the pair of annular members.

[0037] (5) A rolling bearing according to an embodiment includes: an inner ring; an outer ring; a plurality of rolling elements arranged between the inner ring and the outer ring; and the cage according to any one of (1) to (3) above.

[0038] According to the above rolling bearing, the same operation and effect as that of the above retainer are achieved.

[0039] (6) A rolling bearing according to an embodiment includes: an inner ring; an outer ring; a plurality of rolling elements arranged between the inner ring and the outer ring; and the cage described in (4) above.

[0040] According to the above rolling bearing, the same operation and effect as that of the above retainer are achieved.

[0041] (7) The molding method of the retainer of the embodiment is a method of molding the retainer described in (3) above by a mold, the mold having a plurality of runners, a plurality of gates connected to each of the runners, and an annular cavity, the cavity being connected to the plurality of gates at intervals in the circumferential direction, wherein in the cavity, a plurality of pocket molding spaces for molding each of the pocket forming portions and a plurality of angled portion molding spaces for molding each of the angled portion forming portions are alternately formed in the circumferential direction, one of the gates is connected to each of the angled portion molding spaces, and when molten resin flows into the cavity from each of the runners via the gates, the volume of molten resin flowing from one of the two circumferentially adjacent gates is made greater than the volume of molten resin flowing from the other gate.

[0042] According to the molding method of the retainer, in the pocket molding space formed between the corner molding space on one side connected to the gate on one side and the corner molding space on the other side connected to the gate on the other side, the volume of the molten resin flowing in from the corner molding space on one side is greater than the volume of the molten resin flowing in from the corner molding space on the other side. Therefore, the molten resin flowing in from the corner molding space on one side and the molten resin flowing in from the corner molding space on the other side are easy to merge at a circumferential side or the other side of the through hole of the pocket forming portion. As a result, the first welded portion and the second welded portion can be more easily formed in the region on the circumferential side or the other side of the through hole.

[0043] <Details of Implementation Method>

[0044] Hereinafter, preferred embodiments will be described with reference to the drawings.

[0045] [Rolling bearings]

[0046] Figure 1 1 is a cross-sectional view of a rolling bearing 10 according to an embodiment of the present invention. The rolling bearing 10 includes an inner ring 11, an outer ring 12, a plurality of rolling elements 13, and a retainer 14. In the following description, a side closer to the axial center C1 of the rolling bearing 10 is sometimes referred to as an axial inner side, and a side farther from the axial center C1 is sometimes referred to as an axial outer side.

[0047] The inner ring 11 is annular. The outer ring 12 is annular. The outer ring 12 is arranged radially outside the inner ring 11. A plurality of rolling elements 13 are arranged between the inner ring 11 and the outer ring 12. The rolling elements 13 of the present embodiment are balls. The rolling bearing 10 of the present embodiment is a deep groove ball bearing. The outer peripheral surface of the inner ring 11 has a raceway 11a for the balls 13 to roll. The cross section of the raceway 11a is roughly concave arc shape. The inner peripheral surface of the outer ring 12 has a raceway 12a for the balls 13 to roll. The cross section of the raceway 12a is roughly concave arc shape.

[0048] Figure 2 1 is a perspective view showing the cage 14 of the rolling bearing 10. Figure 1 and Figure 2 As shown in FIG. 1 , the cage 14 has a plurality of pockets 15. The plurality of pockets 15 hold the plurality of balls 13 so that they can roll freely. The plurality of pockets 15 are arranged on the cage 14 at intervals in the circumferential direction. When viewed in the radial direction, each pocket 15 is circular. The inner surface of the pocket 15 has a concave curved surface shape that is a part of a spherical surface. The radius of the concave curved surface shape is slightly larger than the radius of the outer peripheral surface of the ball 13 (see also FIG. 1 ). Figure 4 ).

[0049] The retainer 14 of this embodiment is a mating retainer that retains the balls 13 from both sides in the axial direction. The retainer 14 is composed of a pair of annular components 16 that are combined in the axial direction. The pair of annular components 16 are of the same shape. The pair of annular components 16 are connected in a state of being reversed to each other. Each annular component 16 is made of synthetic resin. Each annular component 16 is integrally molded by injection molding.

[0050] Figure 3 1 is a perspective view showing the annular member 16. Figure 2 and Figure 3 As shown, each annular component 16 includes an annular body 17 and a plurality of angular portions 19. The annular body 17 is annular. The annular body 17 is defined as a portion axially outside of a cylindrical surface or a conical surface, and the cylindrical surface or the conical surface connects a first imaginary circle K1 formed by connecting the axially outermost positions of the radially outer openings of each pocket 15 and a second imaginary circle K2 formed by connecting the axially outermost positions of the radially inner openings of each pocket 15. A plurality of back hollow portions 17a are arranged at intervals in the circumferential direction. The plurality of back hollow portions 17a are open on the axially outer end surface of the annular body 17, and are arranged to be recessed into the angular portion 19 axially inward (see also). Figure 1 ). A plurality of angular portions 19 are formed integrally with the annular body 17 at intervals in the circumferential direction of the annular body 17. The plurality of angular portions 19 protrude axially from the annular body 17 toward the annular member 16 on the other side. Each angular portion 19 is a portion between adjacent pocket forming portions 21 (described later) in the annular member 16 (excluding the annular body 17).

[0051] The annular member 16 is configured by alternately forming a plurality of pocket forming portions 21 and a plurality of angled portion forming portions 22 in the circumferential direction. The pocket forming portion 21 is a portion forming each pocket 15 in the annular member 16. The angled portion forming portion 22 is a portion forming each angled portion 19 in the annular member 16. The angled portion forming portion 22 is a portion combining each angled portion 19 in the annular body 17 and the angled portion 19.

[0052] The angled portion 19 includes an angled portion main body 20 and an angled portion protrusion 18. The angled portion protrusion 18 extends from a front end surface 22a of the angled portion main body 20 toward the inside in the axial direction.

[0053] Figure 4 It is a perspective view showing a part of the annular member 16 . Figure 5 This is a diagram showing a portion of a pair of annular components 16 after being disassembled from the radially inner side. Figure 4 and Figure 5 As shown, the front end face 22a of each angular portion main body 20 on the axial inner side is formed flat when viewed in the radial direction. The front end face 22a of each angular portion main body 20 abuts against the front end face 22a of each angular portion main body 20 in the annular member 16 on the other side (refer to Figure 2 ).

[0054] The angular protrusion 18 is coupled to the front end face 22a of each angular body 20. The angular protrusion 18 extends axially toward the annular member 16 on the other side. The angular protrusion 18 is coupled to the radially inner portion of the front end face 22a of the angular body 20, and is coupled to a position of the front end face 22a of the angular body 20 that is deviated from the circumferential center C2 to one side in the circumferential direction. The angular protrusion 18 is formed in a substantially quadrangular prism shape. The radially inner side surface 18a of the angular protrusion 18 constitutes a portion of the inner circumferential surface of the annular member 16 (refer to Figure 2 ). The angled protrusion 18 includes an angled protrusion body 18c extending in the axial direction and a locking protrusion 18b protruding radially outward at a front end portion of the angled protrusion body 18c.

[0055] The inner peripheral surface of each angled portion 19 has a locking groove 22b extending in the axial direction. The locking groove 22b opens at the position of the front end face 22a of the angled portion main body 20. The locking groove 22b is arranged at a position that is biased to the side opposite to the angled portion protrusion 18 relative to the circumferential center C2 of the front end face 22a of the angled portion main body 20. The locking groove 22b allows the angled portion protrusion 18 of the annular component 16 on the other side to be inserted from the front end face 22a side of the angled portion main body 20. The locking groove 22b allows the angled portion protrusion 18 of the annular component 16 on the other side to be inserted from the locking protrusion 18b.

[0056] like Figure 1As shown, the locking groove 22b is connected to the back hollowing portion 17a which is recessed from the end surface of the annular body 17 on the axial outer side to the axial inner side. The radial step surface 22c is formed in the middle of the axial direction of the locking groove 22b. The locking protrusion 18b is locked to the step surface 22c of the locking groove 22b in the axial direction. The angular protrusion body 18c is accommodated in the locking groove 22b. By locking the locking protrusion 18b on the step surface 22c, the pair of annular components 16 will not be separated from each other in the axial direction. The pair of annular components 16 are connected.

[0057] like Figure 3 As shown, all the angled portion forming portions 22 of each annular member 16 have a gate mark 28 (see also Figure 5 The gate mark 28 is a shear mark formed when the gate 46 (described later) of the mold 40 is cut off after the annular member 16 is molded by the mold 40 (described later). In the present embodiment, the gate mark 28 is located at a position biased toward one side in the circumferential direction (the side of the angular protrusion 18) of the inner side surface 22d on the radial inner side of each angular portion forming portion 22. The gate mark 28 is circular.

[0058] As described above, a plurality of gate marks 28 exist at intervals in the circumferential direction on the inner circumferential surface of the annular member 16. Furthermore, the pocket forming portion 21 exists between the gate marks 28 adjacent to each other in the circumferential direction. Figure 2 Illustration of the gate mark 28 is omitted.

[0059] like Figure 2 and Figure 3 As shown, the axially inner end face 21a of each pocket forming portion 21 is formed into a semicircle when viewed in the radial direction. The axially inner end face 21a of each pocket forming portion 21 is a part of a spherical surface having a radius slightly larger than the radius of the ball 13. The pocket forming portions 21 of a pair of annular components 16 are arranged relative to each other in the axial direction to form a pocket 15. One pocket 15 is a part of a spherical surface formed by two end faces 21a. The retaining frame 14 has a plurality of columns 25 in the circumferential direction. The angular portions 19 of a pair of annular components 16 are connected to each other in the axial direction to form a column 25. Each pocket 15 is formed between columns 25 adjacent to each other in the circumferential direction of the retaining frame 14.

[0060] Figure 6 yes Figure 2 Sectional view of the II direction. Figure 3 as well as Figure 6 As shown, a circular through hole 23 is formed at the bottom of each pocket forming portion 21 located at the outermost side in the axial direction of the pocket 15. The through hole 23 penetrates the annular body 17 in the axial direction. The through hole 23 opens at the end surface of the annular body 17 on the axial outer side. By providing the through hole 23, the axial thickness t1 of the bottom of the pocket forming portion 21 can be made thicker than the thickness t11 of the pocket bottom of the conventional annular body (see Fig.11 As a result, the axial width dimension W1 of the rolling bearing 10 (see Figure 1 ) is larger than the width dimension W11 of conventional rolling bearings (refer to Fig.11 )Small.

[0061] Figure 7 This is a front view of the annular member 16 viewed from the axial inside. Figure 7 As shown, the annular component 16 has a weld portion (weld line) 24 between the gate marks 28 adjacent to each other in the circumferential direction. The weld portion 24 is generated when the annular component 16 is molded using a mold 40 (described later). The weld portion 24 is a thin line generated at a portion where the flows of molten resin merge and weld in the mold 40 described later.

[0062] The weld 24 is formed only in region R1 on one circumferential side of the through hole 23 or only in region R2 on the other circumferential side of the through hole 23 between adjacent gate marks 28. Region R1 and region R2 are regions including the angled portion forming part 22 and the pocket forming part 21 except region R3. Region R3 is a region radially outside and radially inside the through hole 23 in a range where the through hole 23 exists in the circumferential direction of the angled portion forming part 22. The weld 24 is not formed in region R3 which is a stress concentration portion of each pocket forming part 21. The weld 24 of the present embodiment is formed in the pocket forming part 21 and / or the angled portion forming part 22 in region R1 or region R2. The weld 24 is formed in the axial direction ( Figure 7 It is formed over the entire thickness of the paper surface (in the direction perpendicular to the paper surface).

[0063] The welded portion 24 includes a first welded portion 24a and a second welded portion 24b. Figure 7 When viewed from the front, the first weld 24a extends in the entire radial direction and the entire axial direction of the region R1 or the region R2. When viewed in the axial direction, the second weld 24b extends from the radial midway position (here, the central position) of the first weld 24a to the through hole 23 in the circumferential direction and the entire axial direction. Figure 2 and Figure 3 Illustration of the welded portion 24 is omitted.

[0064] [Mold]

[0065] Figure 8 It is a perspective view showing a mold 40 for molding the annular member 16 by injection molding. Fig. 9 40 is a top view of the mold. Figure 8 as well as Fig. 9As shown, the mold 40 includes a first mold portion 41 and a second mold portion 42 which are divided into two in the axial direction of the annular member 16. The first mold portion 41 is a fixed mold. The second mold portion 42 is a movable mold which can move in the axial direction relative to the first mold portion 41. Figure 8 In FIG. 1 , for convenience, the first mold section 41 and the second mold section 42 are depicted by imaginary lines (two-dot chain lines).

[0066] The mold 40 also includes a cavity 43, a sprue 44, a plurality of runners 45, and a plurality of gates 46. The cavity 43 is formed between the first mold portion 41 and the second mold portion 42. The cavity 43 is a space filled with molten resin. The cavity 43 is formed in an annular shape corresponding to the shape of the annular member 16. Thus, in the cavity 43, a plurality of pocket molding spaces 43a for molding each pocket forming portion 21 and a plurality of angular portion molding spaces 43b for molding each angular portion forming portion 22 are alternately formed in the circumferential direction. Although not shown in the figure, a cylindrical molding column for molding the through hole 23 is provided in the first mold portion 41 or the second mold portion 42 at a position corresponding to each through hole 23 in the pocket molding space 43a.

[0067] The sprue 44, the plurality of runners 45, and the plurality of gates 46 are passages for supplying molten resin to the cavity 43. The sprue 44 is a passage formed in the second mold portion 42. The sprue 44 extends axially at the center of the annular cavity 43. The sprue 44 of this embodiment is formed in a circular cross section.

[0068] The runner 45 is a passage formed between the first mold part 41 and the second mold part 42. One runner 45 is provided for one angled portion forming part 22. The plurality of runners 45 extend radially outward from the front end of the sprue 44. Each runner 45 of the present embodiment is formed into a quadrilateral cross section.

[0069] A plurality of gates 46 are connected to the radially outer ends of the runners 45. Each gate 46 extends from the radially outer end of each runner 45 toward the radially outer side and toward one side in the axial direction ( Figure 8 Each gate 46 of the present embodiment is formed in a circular cross-section, and is formed so that the diameter gradually decreases toward the front end.

[0070] The front ends of the plurality of gates 46 are connected at intervals in the circumferential direction of the cavity 43. Specifically, the front end of each gate 46 is connected to a position on one side in the circumferential direction (the side of the angular protruding portion 18) of a portion corresponding to the inner side surface 22d of the angular portion forming portion 22 in each angular portion molding space 43b. Thus, each gate 46 is connected to all the angular portion molding spaces 43b.

[0071] The molding method of the annular component 16 is as follows. The molten resin supplied to the sprue 44 of the mold 40 passes through each runner 45 and each gate 46 in sequence and flows into each corner molding space 43b of the cavity 43. The molten resin flowing into each corner molding space 43b flows into the adjacent pocket molding space 43a. Moreover, the molten resin is filled in the entire cavity 43. The molten resin solidifies, and the solidified resin is taken out of the mold 40 as the annular component 16.

[0072] like Fig. 9 As shown, the plurality of gates 46 in this embodiment include a plurality of first gates 46A, a plurality of second gates 46B, and a third gate 46C. The diameter of the front end of the first gate 46A at the position where the cavity 43 opens, the diameter of the front end of the second gate 46B at the position where the cavity 43 opens, and the diameter of the front end of the third gate 46C at the position where the cavity 43 opens are different from each other. Four first gates 46A and four second gates 46B are provided respectively. One third gate 46C is provided. The diameter of the front end of the first gate 46A is larger than the diameter of the front end of the second gate 46B. The diameter of the front end of the second gate 46B is larger than the diameter of the front end of the third gate 46C.

[0073] The first gate 46A and the second gate 46B are arranged adjacent to each other in the circumferential direction. The third gate 46C is arranged at a predetermined position in the circumferential direction (at Fig. 9 The first gate 46A and the second gate 46B are disposed at a position approximately at 10 o'clock in the figure. Thus, the diameters of the front ends of the two gates 46 adjacent to each other in the circumferential direction are different from each other. Therefore, the volume flow rate of the molten resin flowing into the corner portion molding space 43b from the gate 46 with a larger front end diameter among the adjacent gates 46 is greater than the volume flow rate of the molten resin flowing into the corner portion molding space 43b from the other gate 46 with a smaller front end diameter.

[0074] The volume flow rate of the molten resin flowing through the first gate 46A is greater than the volume flow rate of the molten resin flowing through the second gate 46B. The volume flow rate of the molten resin flowing through the first gate 46A is greater than the volume flow rate of the molten resin flowing through the third gate 46C. The volume flow rate of the molten resin flowing through the second gate 46B is greater than the volume flow rate of the molten resin flowing through the third gate 46C.

[0075] The molten resin flowing through the first gate 46A flows from the first gate 46A to one side of the circumference of the cavity 43 and the other side of the circumference of the cavity 43. The molten resin flowing through the second gate 46B flows from the second gate 46B to one side of the circumference of the cavity 43 and the other side of the circumference of the cavity 43. The molten resin flowing through the third gate 46C flows from the third gate 46C to one side of the circumference of the cavity 43 and the other side of the circumference of the cavity 43. With respect to the adjacent first gate 46A and second gate 46B, the volume of the molten resin flowing from the first gate 46A to one side of the circumference of the cavity 43 and the volume of the molten resin flowing from the second gate 46B to the other side of the circumference of the cavity 43 can be made different. With respect to the adjacent first gate 46A and the second gate 46B, the volume of the molten resin flowing from the first gate 46A to the other side in the circumferential direction of the cavity 43 can be made different from the volume of the molten resin flowing from the second gate 46B to the one side in the circumferential direction of the cavity 43. With respect to the adjacent first gate 46A and the third gate 46C, the volume of the molten resin flowing from the first gate 46A to the one side in the circumferential direction of the cavity 43 can be made different from the volume of the molten resin flowing from the third gate 46C to the other side in the circumferential direction of the cavity 43. With respect to the adjacent second gate 46B and the third gate 46C, the volume of the molten resin flowing from the second gate 46B to the other side in the circumferential direction of the cavity 43 can be made different from the volume of the molten resin flowing from the third gate 46C to the one side in the circumferential direction of the cavity 43. By combining the diameter and configuration of the tip of the first gate 46A, the diameter and configuration of the tip of the second gate 46B, and the diameter and configuration of the tip of the third gate 46C, the molten resins can be merged at a position between adjacent gates 46 that is not the exact center in the circumferential direction.

[0076] Through the above, such as Figure 7 As shown, the annular component 16 after molding forms a welded portion 24 in the pocket forming portion 21 in the region R1 on one circumferential side or the region R2 on the other circumferential side relative to each through hole 23. The second welded portion 24b of the welded portion 24 is a thin line generated at a portion where the flows of the molten resin from the radially outer side and the radially inner side of the through hole 23 merge and fuse from the one corner portion molding space 43b. The first welded portion 24a of the welded portion 24 is a thin line generated at a portion where the flows of the molten resin from the radially outer side and the radially inner side of the through hole 23 merge and fuse with the flows of the molten resin from the other corner portion molding space 43b.

[0077] [Effects of the Embodiments]

[0078] As described above, the retainer 14 of the present embodiment has a through hole formed at the bottom of the pocket 15 of the pocket forming portion 21, so that the axial thickness t1 of the bottom of the pocket forming portion 21 can be reduced. Therefore, the rolling bearing 10 using the retainer 14 of the present embodiment can reduce the axial width dimension W1 of the rolling bearing 10. In addition, the weld 24 is formed only in the region R1 on the circumferential side of the through hole 23 between the gate marks 28 adjacent to each other in the circumferential direction, or only in the region R2 on the circumferential side of the through hole 23. Therefore, the retainer 14 of the present embodiment can suppress the formation of the weakest weld in the region R3 that becomes the stress concentration portion of the pocket forming portion 21 during the use of the rolling bearing 10. Therefore, the retainer 14 of the present embodiment has the strength of the retainer 14 despite having the through hole 23 in the pocket forming portion 21.

[0079] Furthermore, the weld 24 includes a first weld 24a extending in the entire radial direction when viewed in the axial direction, and a second weld 24b extending in the circumferential direction from a radially midway position of the first weld 24a to the through hole 23 when viewed in the axial direction. Therefore, the retainer 14 of this embodiment can further improve the strength of the retainer 14 compared to a case where only the second weld 24b is formed to extend in the entire circumferential direction of the region R1.

[0080] In addition, all the angled portion forming parts 22 of the retainer 14 of the present embodiment each have a gate mark 28. That is, when the retainer 14 of the present embodiment is molded using the mold 40, molten resin flows into the mold 40 from the gates 46 corresponding to all the angled portion forming parts 22. Therefore, by controlling the volume of the molten resin flowing from each gate 46, the first weld 24a and the second weld 24b can be easily formed in the region R1 or the region R2 instead of the region R3.

[0081] The retainer 14 of the present embodiment is formed by connecting a pair of annular members 16 in the axial direction. Therefore, the retainer 14 of the present embodiment can further improve the strength of the retainer 14 compared to a crown-shaped retainer formed of only a single annular member.

[0082] In addition, the diameters of the front ends of the two gates 46 adjacent to each other in the circumferential direction of the mold 40 are different from each other. Therefore, the volume of the molten resin flowing from one of the two gates 46 adjacent to each other in the circumferential direction into the cavity 43 on one side in the circumferential direction is greater than the volume of the molten resin flowing from the other gate 46 into the cavity 43 on the other side in the circumferential direction. As a result, by controlling the volume of the molten resin flowing from each gate 46, the first weld 24a and the second weld 24b can be formed more easily in the region R1 or the region R2 rather than in the region R3.

[0083] The embodiments disclosed above are illustrative and non-restrictive in all aspects. For example, the rolling bearing 10 may be an angular contact ball bearing or the like in addition to a deep groove ball bearing. The retainer 14 may be a crown retainer or an angle retainer in addition to a mating retainer. The welded portion 24 may be formed in the pocket forming portion 21 or in the angle forming portion 22 in the region R1 or the region R2.

[0084] The gate 46 of the mold 40 is connected to a portion corresponding to the inner side surface 22d of the angled portion forming portion 22 in each angled portion molding space 43b, but the present invention is not limited thereto. For example, the gate 46 may be connected to a portion corresponding to the angled portion protrusion 18 in each angled portion molding space 43b. In this case, it is needless to say that the gate mark 28 is formed on the angled portion protrusion 18 in the molded retainer 14.

[0085] The number of gates 46 is not limited to the present embodiment. When the gates 46 are an even number, the gates 46 may be composed of two types of gates with different diameters at the front end. In order to make the volume flow rate of the molten resin different, the diameters of the front ends of two gates 46 adjacent to each other in the circumferential direction of the mold 40 are different, but the present invention is not limited to this. For example, two gates 46 adjacent to each other in the circumferential direction may be connected to independent flow paths respectively, so that the inflow pressure of the molten resin into each gate 46 is different.

[0086] Description of symbols

[0087] 10 Rolling bearings

[0088] 11 Inner Circle

[0089] 12 Outer ring

[0090] 13 Ball (rolling element)

[0091] 14 Cage

[0092] 15 pockets

[0093] 16 Ring parts

[0094] 17 Ring

[0095] 18 Corner protrusion

[0096] 19 Angular part

[0097] 20 Corner body

[0098] 21 Pocket forming part

[0099] 22 Angular part forming part

[0100] 23 Through hole

[0101] 24 Welding section

[0102] 24a First welding portion

[0103] 24b Second welding part

[0104] 25 columns

[0105] 28 Gate mark

[0106] 40 Mould

[0107] 43 Cavity

[0108] 43a Pocket forming space

[0109] 43b Angle forming space

[0110] 45 Runner

[0111] 46 Gate

[0112] R1 Region

[0113] R2 Region

[0114] R3 Region

Claims

1. A retainer, made of synthetic resin, comprising an annular body and a plurality of angular portions, wherein a plurality of pockets are formed between the angular portions adjacent to each other in the circumferential direction, wherein the plurality of angular portions protrude from the annular body to one side in the axial direction at intervals in the circumferential direction of the annular body, wherein the pockets retain a plurality of rolling elements of a rolling bearing so as to roll freely, wherein: The retaining frame comprises: A plurality of gate marks are formed at intervals in the circumferential direction; a weld portion formed between the gate marks adjacent to each other in the circumferential direction; and A plurality of pocket forming portions are respectively arranged between the gate marks to form the pockets. Each of the pocket forming portions has a through hole formed in the bottom of the pocket so as to penetrate the bottom of the pocket in the axial direction. The welded portion is formed between the gate marks only in a region on one side of the through hole in the circumferential direction or only in a region on the other side of the through hole in the circumferential direction.

2. The retainer according to claim 1, wherein: The fusion bonded portion has: A first weld portion extending in the entire radial direction when viewed in the axial direction; and The second weld portion extends in the circumferential direction from a radially midway position of the first weld portion to the through hole when viewed in the axial direction.

3. The retainer according to claim 2, wherein: The retainer further includes a plurality of angled portion forming parts, wherein the plurality of angled portion forming parts form each of the angled portions. One gate mark is formed on each of all the angled portion forming portions.

4. The cage according to any one of claims 1 to 3, wherein: A pair of annular members including the annular body and the plurality of angular portions are connected in the axial direction. The retainer includes a column formed by connecting the angular portions of the pair of annular members to each other. 5 . A rolling bearing comprising: an inner ring; an outer ring; a plurality of rolling elements disposed between the inner ring and the outer ring; and the retainer according to claim 1 . 6 . A rolling bearing comprising: an inner ring; an outer ring; a plurality of rolling elements disposed between the inner ring and the outer ring; and the retainer according to claim 4 .

7. A method for molding a retainer, comprising molding the retainer according to claim 3 by a mold, wherein the mold comprises a plurality of runners, a plurality of gates connected to each of the runners, and an annular cavity, wherein the plurality of gates are connected to the cavity at intervals in the circumferential direction, wherein: In the mold cavity, a plurality of pocket forming spaces for forming the pocket forming portions and a plurality of angled portion forming spaces for forming the angled portion forming portions are alternately formed in the circumferential direction. Each of the angular portion molding spaces is connected to a gate. When the molten resin flows from each of the runners through the gate into the cavity, the volume of the molten resin flowing from one of the two gates adjacent to each other in the circumferential direction is made larger than the volume of the molten resin flowing from the other gate.

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