BEARINGS AND BEARING MANUFACTURING METHODS

Abstract

The invention relates to a bearing in which a pair of annular bodies forming a resin cage can be reliably coupled together, and from which it is easy to confirm whether or not the annular bodies are completely coupled together. In the bearing, the annular bodies of the pair of annular bodies 8a, 8b are coupled to each other by a plurality of resin rivets 18, each having a crimped head portion 26. Figure to be published with the abstract: Fig. 1

Description

Title of the invention: BEARING AND MANUFACTURING METHOD FOR BEARINGS technical field

[0001] The present invention relates to a bearing, and a method of manufacturing the bearing. CONTEXT OF THE INVENTION

[0002] A bearing is widely used to support a rotating shaft in electric motors, speed reducers, transmissions, and the like. The bearing comprises an inner ring, an outer ring arranged radially outward from the inner ring, a plurality of rolling elements arranged between the inner and outer rings, and a cage retaining the rolling elements. A resin cage (made of a resin) is sometimes used as the cage due to certain advantages, such as lightness and a degree of freedom in the molding process. A crown-shaped cage, a combination cage, or a similar type of resin cage is commonly used.

[0003] The crown-shaped cage comprises a circular part, and a plurality of pairs of claws extending axially from the circular part and the retaining rolling elements.

[0004] In recent years, electric motors in electric vehicles and similar applications have tended to increase in speed, and consequently, bearings used for speed reducers, transmissions, and similar applications also tend to be used within a high-speed rotational range. If, when a bearing is used within a high-speed rotational range (particularly a rotational range close to the bearing's speed limit), a ring-shaped cage is used as the bearing cage, the pairs of claws in the ring-shaped cage could deform radially outward under the effect of a centrifugal force, thus causing the claws to interfere with the rolling elements.As a method for reducing claw deformation due to centrifugal force, the use of a highly rigid resin material is considered, but such a resin material is generally expensive.

[0005] The crown-shaped cage has claws only on one axial side of the circular portion, and is therefore axially asymmetrical. For this reason, a bearing in which the crown-shaped cage is used may require management of the mounting direction.

[0006] In view of this, a combined cage is used in certain cases as a cage that exhibits high structural rigidity and does not require management of the direction of installation. The applicant of the present application has already proposed combined cages in patent documents 1 to 4 identified below.

[0007] The combined cages of patent documents 1 to 4 comprise a pair of annular bodies axially opposed to each other, and the combined cages are formed by coupling the pair of annular bodies together. A method of engaging engagement claws in respective engagement holes is used as the coupling method.

[0008] More specifically, the combined cages of patent documents 1 to 4 comprise: a pair of annular bodies axially opposed to each other, each annular body having a plurality of pocket-forming portions circumferentially spaced from each other; and a plurality of inter-pocket portions formed each between the corresponding pocket-forming portions circumferentially adjacent to the pocket-forming portions. Pockets are defined between the pocket-forming portions of a first annular body of the pair of annular bodies and the respective pocket-forming portions of the other annular body, and balls are received in the respective pockets.Axially extending engagement claws are formed on each inter-pocket portion of the first annular body, and these engagement claws are inserted into respective axially extending engagement holes in each inter-pocket portion of the other annular body. Hook portions formed on the respective engagement claws are locked with respective stages formed on the inner surfaces of the respective engagement holes, and the locking of the hook portions prevents the engagement claws from disengaging from the engagement holes. As described above, the annular bodies of the pair of annular bodies are coupled together by the engagement of the engagement claws in the engagement holes.

[0009] PRIOR ART DOCUMENTS Patent Document 1: Japanese Publication of Unexamined Patent Application No. 2004-076778 Patent Document 2: Japanese Publication of Unexamined Patent Application No. 2010-112461 Patent Document 3: Japanese Publication of Unexamined Patent Application No. 2013-245762 Patent document 4: Japanese publication of unexamined patent application no. 2020-133663.

[0010] In view of the combined cages of patent documents 1 to 4, it is difficult to reliably couple the annular bodies of the pair of annular bodies to one another. the other, and it is also difficult to confirm whether or not the annular bodies of the pair of annular bodies are completely coupled together.

[0011] That is, since the combined cages of patent documents 1 to 4 have engagement claws larger than the engagement holes, when the engagement claws are inserted into the respective engagement holes, the engagement claws must be forced in while being deformed. The size relationship between the engagement claws and the engagement holes is important. That is, if all the engagement claws are not engaged in all the engagement holes simultaneously, some of the engagement claws may not be fully inserted into some of the engagement holes, and partial separation could occur between the annular bodies of the pair of annular bodies. It is thus difficult to reliably couple the annular bodies of the pair of annular bodies to each other.

[0012] Furthermore, when the engagement claws of one annular body of the pair of annular bodies are inserted into the respective engagement ports of the other annular body so as to couple the annular bodies of the pair of annular bodies to each other, the hook portions of the engagement claws and the stages that engage the respective hook portions are located inside the engagement ports, and visual inspection from the outside is not possible. It is therefore difficult to confirm the engaged state between the hook portions and the stages, and thus difficult to confirm whether or not the first annular body and the second annular body are fully coupled together.

[0013] Furthermore, if the bearing of patent document 1 is used in a high-speed rotation range, seizure could occur inside the bearing due to insufficient (depletion) lubricating oil.

[0014] That is, in the combined cage of patent document 1, the axially outer end surface of each of the annular bodies in the pair of annular bodies is an irregular, corrugated surface having hemispherical portions along the circumferentially spaced ball shapes. Thus, when the bearing is used in a high-speed rotational range, the lubricating oil supplied from outside the bearing is dispersed by the axially irregular end surfaces of the cage and is therefore less likely to penetrate the bearing. Consequently, a lack of lubricating oil occurs inside the bearing, and seizure can occur. In recent years in particular, the viscosity and quantity of lubricating oil have tended to decrease, and seizure is more likely to occur. SUMMARY

[0015] PROBLEMS TO BE SOLVED BY THE INVENTIONThe present invention relates to a bearing in which the annular bodies of a pair of annular bodies forming a resin cage can be reliably coupled together, and from which it is easy to confirm whether or not the annular bodies are completely coupled together.

[0016] To achieve the above objective, the present invention provides a bearing comprising: an inner ring; an outer ring arranged radially outward from the inner ring; a plurality of rolling elements arranged between the inner and outer rings; and a resin cage retaining the rolling elements, in which the resin cage is formed by a pair of annular bodies axially opposed to each other.in which each of the annular bodies comprises: a plurality of pocket-forming parts circumferentially spaced from one another; and a plurality of inter-pocket parts, each formed between a corresponding circumferentially adjacent pair of pocket-forming parts, and in which pockets are defined between the pocket-forming parts of a first annular body of the pair of annular bodies and the respective pocket-forming parts of the other annular body of the pair of annular bodies, and the rolling elements are received in the respective pockets, characterized in that each of the annular bodies has a plurality of rivet holes extending axially through the respective inter-pocket parts, in which the rivet holes of the annular bodies are arranged such that, with the annular bodies of the pair of annular bodies axially opposed to one another,circumferential positions of the rivet holes of the first annular body coincide with circumferential positions of the rivet holes of the other annular body, wherein the annular bodies of the pair of annular bodies are coupled to each other by a plurality of resin rivets composed of a thermoplastic resin, and inserted through the rivet holes of the annular bodies in which the circumferential positions of the rivet holes of the first annular body coincide with the circumferential positions of the rivet holes of the other annular body, and wherein each of the resin rivets comprises: a rivet shank inserted through one of the rivet holes of the first annular body and one of the rivet holes of the other annular body; a rivet head portion formed at one end of the rivet shank,and axially engaged with the first annular body; and a crimped head portion formed by casting the other end of the rivet shaft, and axially engaged with the other annular body [arrangement 1].

[0017] With this arrangement, since each crimped head portion is formed not before, but after, the insertion of the rivet shaft into the rivet holes, the rivet shaft can be inserted into the rivet holes before the crimped head portion, which is larger than the rivet holes, is formed on the rivet shaft. Therefore, the rivet shafts can be reliably inserted into the rivet holes when the The annular bodies are stacked one on top of the other, so that the crimped head sections can be formed on the rivet shafts without spontaneous separation occurring between the annular bodies. The annular bodies can thus be reliably joined together.

[0018] Furthermore, each crimped head portion is located in a position visible when the annular bodies are coupled together. Therefore, by visually checking whether or not the crimped head portion has a shape that prevents it from protruding from the rivet hole, it is easy to confirm whether or not the annular bodies are fully coupled together.

[0019] Furthermore, since, after each rivet shaft is inserted into the rivet holes, the distal end of the rivet shaft is melted to form the crimped head portion, the crimped head portion can be formed to be sufficiently larger than the rivet holes. This makes it possible to reliably couple the annular bodies to one another.

[0020] [Arrangement 2] Bearing according to arrangement 1, in which an axially external end surface of each of the annular bodies comprises a flat surface extending circumferentially continuously around an entire circumference, in which rivet head receiving parts are formed in the respective rivet holes of the first annular body, and the rivet head parts of the resin rivets are received in the respective rivet head receiving parts, and in which crimped head receiving parts are formed in the respective rivet holes of the other annular body, and the crimped head parts of the resin rivets are received in the respective crimped head receiving parts.

[0021] Consequently, since the axially external end surfaces of the annular bodies are not irregularly shaped, when the axially external bearing is used within a high-speed rotational range, and lubricating oil is supplied from outside the bearing towards the axially external end surfaces of the annular bodies, the lubricating oil is less likely to be dispersed and readily penetrates the bearing. A lack of lubricating oil is therefore less likely to occur, thus preventing seizing within the bearing. Furthermore, the resistance to agitation of the lubricating oil can also be reduced, and the rolling torque can thus be lowered.

[0022] [Arrangement 3] Bearing according to arrangement 2, in which the height dimensions of the rivet head parts are greater than the depth dimensions of the rivet head receiving parts.

[0023] With this arrangement, given that, when the resin rivets are pressed by a heated jig to form the crimped head parts, each of the When the rivet head portion is in a state where it protrudes beyond the end surface of the inter-pocket portion, a base can receive the end surface of the rivet head portion, and no gap is defined between the base and the end surface of the rivet head portion. Thus, when each resin rivet is pressed by the heated jig, no axial gap is defined between a seating surface of the rivet head portion and the lower surface of the rivet head receiving portion. When the rivet head portions are formed in this state, there is no axial play between the first annular body and the other annular body, and the axially inner end surfaces of the first annular body and the axially inner end surfaces of the other annular body can be reliably brought into close contact with each other.

[0024] [Arrangement 4] Bearing according to arrangement 2 or 3, in which the crimped head parts are melted and bonded to the inner surfaces of the respective crimped head receiving parts.

[0025] With this arrangement, since the crimped head parts are melted and bonded to the inner surfaces of the respective crimped head receiving parts, the annular bodies of the pair of annular bodies are coupled together more reliably.

[0026] [Arrangement 5] Bearing according to any one of arrangements 1 to 4, wherein each of the inter-pocket parts of each of the annular bodies has an axial protrusion and an axial recess which are formed in a row in a circumferential direction, and wherein the recesses and protrusions of the other annular body are fitted onto the protrusions and recesses of the first annular body, respectively.

[0027] With this arrangement, when the annular bodies are stacked one on top of the other, the recesses of the second annular body are fitted onto the respective projections of the first annular body, and the projections of the second annular body are fitted into the respective recesses of the first annular body, it is possible to achieve circumferential and radial positioning of the second annular body relative to the first annular body. Furthermore, when, during the operation of the bearing, a force (shear force) is applied, causing the annular bodies to slide circumferentially due to a displacement of the rolling elements, the force is received by the projections and recesses as well as the resin rivets 18, and the shear force acting on the resin rivets can thus be distributed, and breakage of the resin rivets can be prevented.Furthermore, since the annular bodies have the same shape, common constituent elements can be used as annular bodies.

[0028] [Arrangement 6] Bearing according to arrangement 5, in which each of the projections of the annular bodies is formed so that one of the two semi-peripheral parts protrudes axially, the two semi-peripheral parts being defined by the bisection of a peripheral edge of a corresponding rivet hole of the rivet holes, and in which each of the recesses of the annular bodies is formed so that the other of the two semi-peripheral parts is axially recessed.

[0029] With this arrangement, since the protrusions and recesses are formed along the peripheral edges of the rivet holes, it is possible to reduce the space required for the installation of the protrusions and recesses.

[0030] [Arrangement 7] Bearing according to arrangement 5 or 6, wherein an outer peripheral surface of each of the projections of the annular bodies is formed in a truncated semi-conical shape such that an outer diameter of it decreases towards a distal end of the projection, and wherein an inner peripheral surface of each of the recesses of the annular bodies is formed in a truncated semi-conical shape such that an inner diameter of it decreases towards a bottom of the recess.

[0031] With this arrangement, since the distal ends of the projections are small, and the openings of the recesses are large, when the annular bodies of the pair of annular bodies are combined together, the projections can be easily fitted into the recesses.

[0032] [Arrangement 8] A bearing according to any one of the arrangements 1 to 4, in which each of the inter-pocket parts of each of the annular bodies has: a first radially extending stage formed such that the other circumferential side of the first stage protrudes axially from one circumferential side of the first stage; and a second radially extending stage formed such that the other circumferential side of the second stage retracts axially from the first circumferential side of the second stage, the first radially extending stage and the second radially extending stage being circumferentially spaced from each other, and the first and second stages of the first annular body are engaged with the second and first stages of the other annular body, respectively, so as to limit the relative circumferential movement of the annular bodies of the pair of annular bodies.

[0033] With this arrangement, when the annular bodies are combined, the first and second stages of the first annular body mesh with the second and first stages of the other annular body, and this meshing allows circumferential and radial positioning of the other annular body relative to the first annular body. Furthermore, when a force (shear force) is applied during bearing operation, which causes sliding Circumferentially, the annular bodies, due to an offset of the rolling elements, receive the force on the first and second stages as well as the resin rivets. The shear force acting on the resin rivets can thus be distributed, preventing their breakage. Furthermore, since the annular bodies have the same shape, common components can be used as annular bodies.

[0034] [Arrangement 9] Rolling according to any one of arrangements 1 to 4, wherein the number of pockets is an even number, wherein a single radially extending stage is formed in each of the inter-pocket parts of the annular bodies, wherein the stages of the annular bodies are formed so that the stages of each circumferentially adjacent pair of inter-pocket parts between which one of the corresponding pocket-forming parts is situated are symmetrical to each other in a circumferential direction, and wherein the stages of the first annular body are engaged with the respective stages of the other annular body so as to restrict the circumferential relative motion of the pair of annular bodies.

[0035] With this arrangement, when the annular bodies of the pair of annular bodies are combined, the stages of the first annular body mesh with the respective stages of the other annular body. This meshing allows for circumferential and radial positioning of the other annular body relative to the first annular body. Furthermore, when a force (shear force) is applied circumferentially during the operation of the bearing, causing the annular bodies to slide due to a misalignment of the rolling elements, the force is received by the treads as well as by the resin rivets. The shear force acting on the resin rivets can thus be distributed, and breakage of the resin rivets can be prevented. Moreover, since the annular bodies have the same shape, common constituent elements can be used as annular bodies.

[0036] [Arrangement 10] Bearing according to any one of arrangements 1 to 9, wherein the rolling elements are balls, wherein axially interior end surfaces of the pocket-forming parts of the annular bodies include inner pocket surfaces having an axially concave hemispherical shape, and wherein each of the inner pocket surfaces has an oil reservoir groove extending towards both circumferential sides through a bottom of the inner pocket surface.

[0037] With this arrangement, since the lubricating oil is kept in the oil reservoir grooves, a lack of lubricating oil can be prevented even when the amount of lubricating oil supplied from the outside is low.

[0038] [Arrangement 11] Bearing according to arrangement 10, wherein a groove width has of each of the oil reservoir grooves in the inner surfaces of pocket is fixed at a < (b / 2), where b is a radial width of one of the pockets, and in which a depth c (mm) of each of the oil reservoir grooves is fixed at c < 1.0.

[0039] With this arrangement, since the groove width of each oil reservoir groove is less than the radial width of the pocket, and the oil reservoir groove is also shallow, the lubricating oil can be effectively retained in the oil reservoir groove due to the surface tension action of the lubricating oil.

[0040] [Arrangement 12] Bearing according to arrangement 10 or 11, in which a length d of each of the oil reservoir grooves seen in the axial direction is fixed at (e / 2) < d, where e is a diameter of one of the rolling elements.

[0041] With this arrangement, it is possible to supply lubricating oil to sufficient areas of the surfaces of the rolling elements.

[0042] In order to achieve the above objective, the present invention also proposes a method for manufacturing a bearing, the bearing comprising: an inner ring; an outer ring disposed radially outwards from the inner ring; a plurality of rolling elements disposed between the inner ring and the outer ring; and a resin cage retaining the rolling elements, in which the resin cage is constituted by a pair of annular bodies axially opposed to each other, in which each of the annular bodies comprises: a plurality of pocket-forming parts circumferentially spaced from each other; and a plurality of inter-pocket parts each formed between a corresponding circumferentially adjacent pair of pocket-forming parts,in which pockets are defined between the pocket-forming parts of one annular body of the pair of annular bodies and the respective pocket-forming parts of the other annular body of the pair of annular bodies, and the rolling elements are received in the respective pockets, in which each of the annular bodies has a plurality of rivet holes extending axially through the respective inter-pocket parts, in which the rivet holes of the annular bodies are arranged so that, with the annular bodies of the pair of annular bodies axially opposed to each other, circumferential positions of the rivet holes of the first annular body coincide with circumferential positions of the rivet holes of the other annular body, in which the annular bodies of the pair of annular bodies are coupled to each other by a plurality of resin rivets composed of a thermoplastic resin,and inserted through the rivet holes of the first annular body in which the circumferential positions of the rivet holes of the first annular body coincide with the circumferential positions of the rivet holes of the other annular body, in which each of the resin rivets comprises: a rivet shaft inserted through one of the holes, of rivet of the first annular body and one of the rivet holes of the other annular body; a rivet head portion formed at one end of the rivet shaft, and axially engaged with the first annular body; and a crimped head portion formed by melting the other end of the rivet shaft, and axially engaged with the other annular body, and wherein the manufacturing process comprises: a first step of superimposing the annular bodies one on top of the other, and of inserting the resin rivets through the rivet holes of the annular bodies; and a second step of forming, after the first step, the crimped head portions by pressing a heated jig against the other ends of the resin rivets, thereby pushing and widening the other ends of the resin rivets while heating and melting the other ends of the resin rivets [Arrangement 13].

[0043] EFFECTS OF THE INVENTION In the bearing of the present invention, since each rivet head portion is formed not before, but after, the insertion of the rivet shaft into the rivet holes, the rivet shaft can be inserted into the rivet holes before the rivet head portion, which is larger than the rivet holes, is formed on the rivet shaft. Therefore, the rivet shafts can be reliably inserted into the rivet holes when the annular bodies are overlapped, so that the rivet head portions can be formed on the rivet shafts without spontaneous separation occurring between the annular bodies. The annular bodies can thus be reliably coupled together. Furthermore, each rivet head portion is located in a position visible when the annular bodies are coupled together.Therefore, by visually checking whether or not the crimped head part has a shape that prevents it from coming out of the rivet hole, it is easy to confirm whether or not the annular bodies are completely mated together. Brief description of the drawings

[0044] The [Fig. 1] is a view of a bearing of a first embodiment seen in the axial direction. [Fig.2] is a cross-sectional view taken along line II-II of [Fig.1]. Fig. 3 is a cross-sectional view taken along line III-III of Fig. 2, in which rolling elements are located at the centre. Fig. 4 is a cross-sectional view illustrating a state in which a resin cage of Fig. 3 is being assembled, and annular bodies of a pair of annular bodies are axially opposed to each other so as to be spaced apart with balls interposed between the annular bodies. Fig. 5 is an enlarged view illustrating a resin cage on Fig. 2, and its surroundings. Fig. 6 is a view illustrating a state in which the annular bodies of the pair of annular bodies of Fig. 4 are brought into buttocks with each other, and then resin rivets are inserted into rivet holes (the crimped head parts of Fig. 5 have not yet been formed). Figure 7 is an exploded perspective view of the resin cage in which the crimped head portions have not yet been formed on the resin rivets of Figure 3. Figure 8A is a view illustrating a state immediately before a heated jig is pressed against the distal end of the resin rivet. Fig. 8B is a view illustrating a state in which the distal end of the resin protrusion on Fig. 8A is melted and begins to deform. Figure 8C illustrates a state in which the distal end of the resin rivet in Figure 8B is further deformed, and the deformed portion is about to come into contact with the lower surface of a crimped head receiving portion. Figure 8D illustrates a state in which the heated jig is continuously pressed against the distal end of the resin rivet from the state in Figure 8C, thus melting and bonding the crimped head portion to the inner surface of the crimped head receiving portion. [Fig.9A] is a view illustrating a reference example in which a resin rivet is used, which has a rivet head portion whose height dimension is smaller than the depth dimension of the rivet head receiving portion, the view corresponding to [Fig.8A]. Fig. 9B is a view illustrating a state in which the resin rivet of Fig. 9A is pressed by the heated jig, and is moved in the axial direction. The [Fig. 10] is a view of a pocket of a first annular body of the pair of annular bodies of the [Fig. 7], and their surroundings when viewed axially from the side of the other annular body. Fig. 11 is a cross-sectional view taken along line XLXI of Fig. 10. [Fig. 12] is a view illustrating a variant in which a stepped resin rivet is used, the view corresponding to [Fig. 8A]. [Fig.13] is a view of the stepped resin rivet from [Fig.12]. [Fig. 14] is a view of a tapered resin rivet. Fig. 15 is a view illustrating a state in which a resin cage of Fig. 12 is being assembled, resin rivets as illustrated in Fig. 13 are being press-fitted into respective rivet holes of the first annular body previously, and the first annular body is axially opposed to the other annular body with balls interposed between them. The [Fig. 16] is a view of a bearing of a second embodiment seen in the axial direction. Figure 17 is a view of the bearing in Figure 16, the view corresponding to Figure 3. Figure 18 is a view of the bearing in Figure 16, the view corresponding to Figure 4. Figure 19 is a view of a resin cage of the bearing in Figure 16, the view corresponding to Figure 7. [Fig. 20] is a view illustrating an annular body of the bearing in [Fig. 16], the view corresponding to [Fig. 10]. Figure [Fig. 21] is a view of a bearing of a third embodiment seen in the axial direction. [Fig.22] is a view of the bearing in [Fig.21], the view corresponding to [Fig.3]. Figure 23 is a view of the bearing in Figure 21, the view corresponding to the [Fig.4] [Fig.24] The [Fig.24] is a view illustrating a resin cage of the bearing in the [Fig.21], the view corresponding to the [Fig.7]. [Fig.25] is a view illustrating an annular body of the bearing in [Fig.21], the view corresponding to [Fig. 10]. Description of the implementation methods

[0045] [First embodiment] Figures 1 to 11 illustrate a bearing in which a resin cage according to a first embodiment of the present invention is used. As illustrated in [Fig. 2], this bearing comprises an inner ring 1; an outer ring 2 arranged radially outwards from the inner ring 1; a plurality of circumferentially spaced rolling elements 4 arranged in an annular inner bearing space 3 defined between the inner ring 1 and the outer ring 2; and a resin cage 5 retaining the rolling elements 4.

[0046] As used here, the terms "axial" and "axially" refer to the direction along the central axis of the bearing; the terms "radial" and "radially" refer to a direction orthogonal to the central axis of the bearing; and the terms "circumferential" and "circumferentially" refer to the direction around the central axis of the bearing.

[0047] A raceway groove for the inner ring 6, on which the rolling elements 4 roll, is formed on the outer periphery of the inner ring 1. The raceway groove for the inner ring 6 is an arc-shaped groove having a symmetrical concave arc-shaped cross-section in the axial direction, and extending along the surfaces of the rolling elements 4. The raceway groove for the inner ring 6 is formed at level of the axial center of the outer peripheral surface of the inner ring 1 so as to extend in the circumferential direction.

[0048] The outer groove 2 has, on its inner periphery, an outer ring raceway groove 7 on which the rolling elements 4 roll. The outer ring raceway groove 7 is an arc-shaped groove having a symmetrical concave arc-shaped cross-section in the axial direction, and extending along the surfaces of the rolling elements 4. The outer ring raceway groove 7 is formed at the axial center of the inner peripheral surface of the outer ring 2 so as to extend in the circumferential direction.

[0049] The rolling elements 4 are radially interposed between the inner ring raceway groove 6 and the outer ring raceway groove 7. This bearing does not have sealing elements that close the axial ends of the inner bearing space 3, and the inner bearing space 3 is open on two axial sides between which the rolling elements 4 are interposed. This bearing is used by introducing lubricating oil supplied from outside the bearing into the inner bearing space 3 through an axial opening in the inner bearing space 3. The rolling elements 4 are balls in this embodiment. This bearing is a deep groove ball bearing.

[0050] The resin cage 5 consists of a pair of annular bodies 8a and 8b (a first annular body 8a and the other annular body 8b) axially opposed to each other. The resin cage 5 is a combined cage formed by coupling the first annular body 8a and the other annular body 8b to each other such that the axially inner end surfaces 9a of the first annular body 8a (i.e., the surfaces of the first annular body 8a axially opposite the other annular body 8b) (left side in [Fig. 2]), and the axially inner end surfaces 9b of the other annular body 8b (i.e., the surfaces of the other annular body 8b axially opposite the first annular body 8a) (right side in [Fig. 2]) are superimposed on each other. The annular bodies are made of a resin material. The resin material can be a thermoplastic resin or a thermosetting resin.

[0051] As illustrated in [Fig. 7], the first annular body 8a comprises a plurality of first pocket-forming parts 10a; and a plurality of first inter-pocket parts 1a. The first pocket-forming parts 10a are circumferentially spaced from one another. The first inter-pocket parts 1a are each formed between the corresponding circumferentially adjacent pair of pocket-forming parts 10a. The first annular body 8a is formed in an annular shape such that the pocket-forming parts 10a alternate circumferentially with the inter-pocket parts 1a. The other annular body 8a also has pocket-forming parts 10b and inter-pocket parts 11b having the same structures as the pocket-forming parts 10a and the inter-pocket parts 1a of the first annular body 8a.

[0052] As illustrated in [Fig. 3], the pocket-forming parts 10a (left side in [Fig. 3]) are axially opposed to the respective pocket-forming parts 10b (right side in [Fig. 3]). Furthermore, the inter-pocket parts 11a (left side in [Fig. 3]) are axially opposed to the respective inter-pocket parts 11b (right side in [Fig. 3]). Pockets 12 are defined between the first pocket-forming parts 10a and the respective pocket-forming parts 10b, and the rolling elements 4 are received in the respective pockets 12. The pockets 12 are hole-shaped parts which extend through the resin cage 5 in the radial direction (direction orthogonal to the surface of the sheet on the [Fig.3]), and the rolling elements 4 are received in the respective pockets 16 so as to partially protrude beyond the resin cage 5 in the direction of the radially inner and outer sides.The axially inner end surfaces of the pocket-forming parts 10a and 10b (end surfaces of the pocket-forming parts 10a opposite the other annular body 8b, and end surfaces of the pocket-forming parts 10b opposite the first annular body 8a) include inner pocket surfaces 13 having an axially concave hemispherical shape.

[0053] The axially external end surfaces 14a and 14b of the annular bodies 8a and 8b each comprise a flat surface extending circumferentially and continuously around the entire circumference. That is to say, the axially external end surfaces 15a of the pocket-forming parts 10a of the first annular body 8a (their opposite end surfaces from the side on which the pocket-forming parts 10a are opposite the pocket-forming parts 10b), and the axially external end surfaces 16a of the inter-pocket parts 1a (their opposite end surfaces from the side on which the inter-pocket parts 1a are opposite the inter-pocket parts 11b) form a flat surface that is perpendicular to the axial direction, and that extends circumferentially and continuously around the entire circumference of the first annular body 8a.The axially external end surfaces 14b of the other annular body 8b also have the same structure as the axially external end surfaces 14a of the first annular body 8a.

[0054] As illustrated in [Fig. 7], a plurality of rivet holes 17a are formed in the respective inter-pocket portions 11a of the annular body 8a so as to extend axially through the annular body 8a, and a plurality of rivet holes 17b are formed in the respective inter-pocket portions 11b of the annular body 8b of in such a way as to extend axially through the annular body 8b. The rivet holes 17a and 17b are arranged so that when the annular bodies 8a and 8b are axially opposed to each other, the circumferential positions of the rivet holes 17a of the first annular body 8a coincide with the circumferential positions of the rivet holes 17b of the other annular body 8b. In this embodiment, the rivet holes 17a are each arranged at the center of the portion between the corresponding pair of adjacent pockets 12, i.e., at a circumferential bisecting position of this portion, and the rivet holes 17b are also each arranged at the center of the portion between the corresponding pair of adjacent pockets 12, i.e., at a circumferential bisecting position of this portion.Furthermore, the rivet holes 17a and 17b are arranged so that when the annular bodies 8a and 8b are axially opposed to each other, the radial positions of the rivet holes 17a of the first annular body 8a coincide with the radial positions of the rivet holes 17b of the other annular body 8b. Resin rivets 18 are inserted through the respective rivet holes 17a of the first annular body 8a, and the respective rivet holes 17b of the other annular body 8b, and the annular bodies 8a and 8b are coupled together by the resin rivets 18.

[0055] As illustrated in [Fig. 5], each rivet hole 17a of the first annular body 8a (left side in [Fig. 5]) has a rivet head receiving portion 19a open onto the axially external end surfaces 16a of the corresponding inter-pocket portion 1a of the first annular body 8a; and a rivet shaft insertion hole 20a connected to the rivet head receiving portion 19a. The rivet head receiving portion 19a has a lower surface 21a; and a lateral surface 22a extending from the lower surface 21a. The lateral surface 22a of the rivet head receiving portion 19a is formed in a truncated conical shape such that its inner diameter increases from the lower surface 21a towards the axially external side. A portion of the rivet head 25 (of each resin rivet 18) is received in the rivet head receiving portion 19a. On the [Fig.[5] The axially external end surface 29 of the rivet head portion 25 is located on the same plane as the axially external end surface 16a of the inter-pocket portion 1la. The rivet head portion 25 may slightly protrude beyond the axially external end surface 16a of the inter-pocket portion 1la (the amount of protrusion of the rivet head portion 25 is less than 5% of the axial width dimension of the inter-pocket portion 1la). The depth dimension of the rivet head receiving portion 19a is fixed at 10 to 30% of the axial width dimension of the inter-pocket portion 1la (i.e., the width dimension of the axially internal end surface 23a of the inter-pocket portion 1la to its axially external end surface 16a).

[0056] The rivet shaft insertion holes 20a in the first annular body 8a are pillar-shaped holes (column holes in [Fig. 5]) through which the respective rivet shafts 24 are inserted. The rivet shafts 24 are inserted through the respective rivet shaft insertion holes 20a.

[0057] Each rivet hole 17b of the other annular body 8b (right side in [Fig. 5]) has a crimped head receiving portion 19b open onto the axially outer end surface 16b of the corresponding inter-pocket portion 11b of the other annular body 8b; and a rivet shaft insertion hole 20b connected to the crimped head receiving portion 19b. The crimped head receiving portion 19b has a lower surface 21b; and a lateral surface 22b extending from the lower surface 21b. The lateral surface 22b of the crimped head receiving portion 19b is formed in a truncated conical shape such that its inner diameter increases from the lower surface 21b towards the axially outer side. A crimped head part 26 (of each resin rivet 18) is received in the crimped head receiving part 19b.The depth dimension of the crimped head receiving part 19b is fixed at 10 to 30% of the axial width dimension of the inter-pocket part 11b (i.e. the width dimension from the axially inner end surface 23b of the inter-pocket parts 11b to its axially outer end surfaces 16b).

[0058] The rivet shaft insertion holes 20b in the other annular body 8b are pillar-shaped holes (column holes in [Fig. 5]) through which the respective rivet shafts 24 are inserted. The rivet shafts 24 are inserted through the respective rivet shaft insertion holes 20b.

[0059] Here, in [Fig. 5], the rivet head receiving portions 19a and the crimped head receiving portions 19b have the same shape and dimensions. The rivet shaft insertion holes 20a of the first annular body 8a and the rivet shaft insertion holes 20b of the other annular body 8b also have the same shape and dimensions.

[0060] Each resin rivet 18 comprises a rivet shaft 24; a rivet head portion 25 formed at one end of the rivet shaft 24; and a crimped head portion 26 formed at the other end of the rivet shaft 24. The rivet head portions 25 engage axially with the first annular body 8a. The crimped head portions 26 engage axially with the other annular body 8b. Each rivet head portion 25 has an outside diameter larger than that of the rivet shaft 24 and is formed into a truncated conical shape such that its outside diameter increases in the direction of the axially outward side in [Fig. 5]. The rivet head portions 25 may be columnar rivet head portions having a constant outside diameter along the axial direction. The seating surfaces 27 of the The rivet head portions 25 are in contact with the lower surfaces 21a of the respective rivet head receiving portions 19a. The lateral surfaces 28 of the rivet head portions 25 are in contact with the lateral surfaces 22a of the respective rivet head receiving portions 19a. The axially external end surfaces 29 of the rivet head portions 25 include flat surfaces that are perpendicular to the axial direction. The cross-sectional area of ​​each rivet head portion 25 is larger than the cross-sectional area of ​​the rivet shaft insertion portion 20a. The cross-sectional area of ​​the rivet head portion 25 is fixed at 1.5 to 4.0 times the cross-sectional area of ​​the rivet shaft insertion portion 20a. The height dimension of the rivet head portion 25 is fixed at 10 to 30% of the axial width dimension of the inter-pocket portion 1a.

[0061] The rivet shafts 24 are each formed in a pillar shape (column shape in [Fig. 5]) so as to extend in the axial direction. The rivet head portions 26 are formed in a flange shape so as to project from the outer periphery of the rivet shaft 24 in the direction perpendicular to the longitudinal direction of the rivet shaft 24. The axially outer end surfaces 30 of the rivet head portions 26 are each formed in a dome shape (convex curved surface bulging towards the axially outer side). The seat surfaces 31 of the rivet head portions 26 are in contact with the lower surfaces 21b of the respective rivet head receiving portions 19b. The height dimension of each rivet head portion 26 is equal to or less than the depth dimension of the rivet head receiving portion 19b. In [Fig.[5], the height dimension of the crimped head part 26 is equal to the depth dimension of the crimped head receiving part 19b. That is to say, the axially external end surface 30 of the crimped head part 26 is located on the same plane as the axially external end surface 16b of the inter-pocket part 11b so as not to protrude axially outwards from the crimped head receiving part 19b.

[0062] The lateral surface 32 of each rivet head portion 26 is in contact with the lateral surface 22b of the rivet head receiving portion 19b. More specifically, the lateral surface 32 of the rivet head portion 26 is in contact with the lateral surface 22b of the rivet head receiving portion 19b, in the direction of the axially outward side from the end of the rivet head receiving portion 19b on the side of the lower surface 21b. The cross-sectional area of ​​the rivet head portion 26 is larger than the cross-sectional area of ​​the rivet shaft insertion hole 20b. The cross-sectional area of ​​the rivet head portion 26 is fixed at 1.5 to 4.0 times the cross-sectional area of ​​the shaft insertion hole. rivet 20b. The height dimension of the crimped head part 26 is fixed at 10 to 30% of the axial width dimension of the inter-pocket part 11b.

[0063] The resin rivets 18 are composed of a thermoplastic resin. Polyamide (PA), polyphthalamide (PPA), polyphenylene sulfide (PPS), or similar resins may be used as the thermoplastic resin. It is preferable, from the point of view of rigidity, to mix a fiber-reinforced material into the thermoplastic resin. Glass fiber, carbon fiber, or similar materials may be used as the fiber-reinforced material.

[0064] As illustrated in [Fig. 7], each inter-pocket portion 1la of the first annular body 8a is formed with a projection 33a projecting axially beyond the axially inner end surface 9a of the first annular body 8a, and a recess 34a hollowed out axially from the axially inner end surface 9a. Each inter-pocket portion 11b of the other annular body 8b is also formed with a projection 33b and a recess 34b that have the same structures as the projection 33a and the recess 34a of the inter-pocket portion 1la of the first annular body 8a. The structure of the projections 33a and the recesses 34a of the first annular body 8a and their surroundings is described below.Having regard to the projections 33b and the recesses 34b of the other annular body 8b and their surroundings, corresponding elements are designated by the same reference numbers or by reference numbers with the letter 'a' at the end replaced by 'b', and their description is omitted.

[0065] Each projection 33a is formed in a respective inter-pocket portion of the inter-pocket portions 1a, and each recess 34a is also formed in a respective inter-pocket portion of the inter-pocket portions 1a. As illustrated in [Fig. 10], the projection 33a is formed such that one of the two semi-peripheral portions protrudes in the axial direction, the two semi-peripheral portions being defined by the bisection of the peripheral edge of the rivet hole 17a along an imaginary radial straight line L1 which connects the center of the first annular body 8a to the center of the rivet hole 17a. The recess 34a is formed such that the other semi-peripheral portion is hollowed out in the axial direction.

[0066] As illustrated in [Fig. 4], the axial length dimension of the projection 33a is fixed at 10 to 20% of the axial width dimension of the inter-pocket portion 1a. As illustrated in [Fig. 10], the projection 33a is formed in a semi-circular arc shape so as to present a thickness in the outward direction in the radial direction (this "radial direction" is n on the base of the rivet hole 17a) from the peripheral edge of the rivet hole 17a viewed in the axial direction. The thickness dimension of the projection 33a is smaller than the hole diameter of the rivet shaft insertion hole 20a. More precisely, the thickness dimension of the projection 33a is fixed at 1 / 10 to 1 / 2 of the hole diameter of the rivet shaft insertion hole. 20a. The end surfaces 35a of the projection 33a on both sides thereof in the circumferential direction (this circumferential direction being based on the rivet hole 17a) are surfaces perpendicular to the circumferential direction of the annular body, and are formed on the same plane in a row in the radial direction.

[0067] As illustrated in [Fig. 4], the inner peripheral surface 36a of the projection 33a is formed into a cylindrical shape so as to have a constant inner diameter. The outer peripheral surface 37a of the projection 33a is formed into a truncated semi-conical shape such that its outer diameter decreases towards the distal end of the projection 33a. The inner peripheral surface 39a of the recess 34a is formed into a truncated semi-conical shape such that its inner diameter decreases towards the bottom of the recess 34a.

[0068] The axial depth dimension of the recess 34a is fixed at 10 to 20% of the axial width dimension of the second inter-pocket part lia. As illustrated in [Fig. 10], the recess 34a is formed in a semi-circular arc shape so as to present a thickness in the direction of the outward side in the radial direction (this radial direction is based on the rivet hole 17a) from the peripheral edge of the rivet hole 17a seen in the axial direction.

[0069] As illustrated in [Fig. 7], the end surfaces 38a of the recess 34a on both sides thereof in the circumferential direction (this circumferential direction is based on the rivet hole 17a) are opposite the end surfaces 35b of the projection 33b on both sides thereof in the circumferential direction (this circumferential direction is based on the rivet hole 17a). The end surfaces 35a of the projection 33a on both sides thereof in the circumferential direction (this circumferential direction is based on the rivet hole 17b) are opposite the end surfaces 38b of the recess 34b on both sides thereof in the circumferential direction (this circumferential direction is based on the rivet hole 17b).

[0070] As illustrated in Figures 4 and 7, the end surfaces 35a of the projection 33a on both sides thereof in the circumferential direction (this circumferential direction is based on the rivet hole 17a) face each other, on one side and the other side of the annular body in the circumferential direction, and on the other side (upper side in [Fig. 4]) in the circumferential direction. The end surfaces 38a of the recess 34a on both sides thereof in the circumferential direction (this circumferential direction is based on the rivet hole 17a) both face the other side (upper side in [Fig. 4]) of both sides of the annular body in the circumferential direction.

[0071] As illustrated in [Fig. 3], the projections 33a of the first annular body 8a are fitted into the respective recesses 34b of the other annular body 8b. The surfaces The end surfaces 35a of each projection 33a on both sides thereof in the circumferential direction (this circumferential direction is based on the rivet hole 17a) are in contact with the end surfaces 38b of the recess 34b on both sides thereof in the circumferential direction (this circumferential direction is based on the rivet hole 17b). The outer peripheral surface 37a of the projection 33a is in contact with the inner peripheral surface 39b of the recess 34b.

[0072] Similarly, the projections 33b of the other annular body 8b are fitted into the respective recesses 34a of the first annular body 8a. The end surfaces 38a of each recess 34a on both sides thereof in the circumferential direction (this circumferential direction is based on the rivet hole 17a) are in contact with the end surfaces 35b of the projection 33b on both sides thereof in the circumferential direction (this circumferential direction is based on the rivet hole 17b). The inner peripheral surface 39a of the recess 34a is in contact with the outer peripheral surface 37b of the projection 33b.

[0073] The inner peripheral surface 36a of the projection 33a, which has a semi-circular arc shape, forms part of a cylindrical inner peripheral surface of the rivet shaft insertion hole 20a. The inner peripheral surface 36a of the projection 33a of the first annular body 8a and the inner peripheral surface 36b of the projection 33b of the other annular body 8b are opposite in the circumferential direction of the annular bodies so as to form a hole constituting part of the rivet shaft insertion holes 20a and 20b, and the rivet shaft 24 is inserted through this hole.

[0074] As illustrated in [Fig. 10], the inner pocket surface 13 of each pocket-forming part 10a has an oil reservoir groove 40 having a circular arc-shaped cross-section extending at a constant depth (see [Fig. 11]) relative to the inner pocket surface 13. The oil reservoir groove 40 extends towards both circumferential sides through the bottom 41 of the inner pocket surface 13 of the pocket-forming part 10a. More specifically, the oil reservoir groove 40 extends linearly in the perpendicular direction towards an imaginary radial straight line L2 passing through the center of the pocket 12 when viewed in the axial direction.The oil reservoir groove 40 of the pocket-forming section 10a extends towards sections where the inner pocket surface 13 is connected to the axially inner end surfaces 23a of the corresponding adjacent inter-pocket sections 1a (surface of the first annular body 8a axially opposite the other annular body 8b). Both ends of the oil reservoir groove 40 of the pocket-forming section 10a are open to the axially inner end surfaces 23a. This oil reservoir groove 40 has the same structure as the groove of . oil reservoir 40 of the pocket formation part 10a is also formed in each pocket formation part 10b.

[0075] As illustrated in [Fig.3], the oil reservoir groove 40 of the pocket-forming part 10a of the first annular body 8a and the oil reservoir groove 40 of the pocket-forming part 10b of the other annular body 8b are connected to each other at the two circumferential ends of the inner pocket surface 13 of the pocket-forming part 10a and at the two circumferential ends of the inner pocket surface 13 of the pocket-forming part 10b so as to form a single annular groove (i.e., an annular groove extending around the entire circumference of the inner pocket surfaces 13).

[0076] As illustrated in [Fig. 1 1], the groove width a of the oil reservoir groove 40 is fixed at a < (b / 2), where b is the radial width of the pocket 12. The depth c (mm) of the oil reservoir groove 40 is fixed at c < 1.0. The depth c of the oil reservoir groove 40 refers to the depth to the bottom 42 of the oil reservoir groove 40 from the part of the oil reservoir groove 40 connected to the inner surface of the pocket 13.

[0077] As illustrated in [Fig. 10], the length d (chord length) of the oil reservoir groove 40 viewed in the axial direction is fixed at (e / 2) < d, where e is the diameter of the rolling element 4 (see [Fig. 3]).

[0078] In this embodiment, as illustrated in [Fig.7], the other annular body 8b has the same shape as the first annular body 8a, and the annular body 8b is arranged in an orientation reversed with respect to the annular body 8a.

[0079] A method for manufacturing the bearing described above is exemplified and described below. First, the rolling elements 4 are placed between the inner ring 1 and the outer ring 2 shown in [Fig. 2], and the rolling elements 4 are positioned so as to be arranged at equal intervals in the circumferential direction. Next, as shown in [Fig. 4], the annular bodies 8a and 8b are positioned so as to be axially opposed to each other, and so as to interpose the rolling elements 4 between them. Then, as shown in [Fig. 6], the rivet holes 17a of the first annular body 8a are aligned with the rivet holes 17b of the other annular body 8b, and the annular bodies 8a and 8b are stacked one on top of the other. Next, the resin rivets 18 are inserted from the rivet holes 17a of the first annular body 8a towards the rivet holes 17b of the other annular body 8b until the seating surfaces 27 (see the [Fig.5]) Rivet head parts 25 come into contact with the lower surfaces 21a of the rivet head receiving parts 19a. Beforehand, the length of each resin rivet 18 is fixed to a length enabling the resin rivet 18 to protrude beyond the axially external end surface 14b of the other. annular body 8b. The peripheral edge of the distal end of each resin rivet 18 has a chamfered shape in order to smoothly insert the resin rivet 18 into the rivet holes 17a and 17b.

[0080] Next, as illustrated in Figures 8A to 8D, the crimped head portions 26 are formed to prevent the resin rivets 18 from exiting the rivet holes 17b, and the annular bodies 8a and 8b are mated together. The crimped head portions 26 can be formed by carrying out a first step (the step described above) in which the resin rivets 18 are inserted through the rivet holes 17a and 17b; and a second step in which the distal ends of the resin rivets 18 are pressed and melted with a heated jig 43 so as to be pushed and enlarged outwards, and then the melted portions are solidified. More specifically, the heating jig 43, which is now at a high temperature, is pressed against the distal end of the resin rivets 18 (see [Fig.8A]), and the distal ends of the resin rivets 18 are melted by the heat transferred from the heating jig 43.Each resin rivet 18 is further pressed by the heating jig 43 so as to enlarge a molten portion of the distal end of the resin rivet 18, and so as to push and widen the molten portion of the resin rivet 18 outwards (see [Fig. 8B]). When the heating jig 43 is moved towards the vicinity of the axially outward end surface 16b of each inter-pocket portion 11b (see [Fig. 8C]), and the heating jig 43 is separated from the resin rivet 18, the molten portion is naturally cooled and hardened, thus forming the crimped head portion 26. That is, the crimped head portion 26 refers to the head of the resin rivet 18 formed by the melting of the distal end of the resin rivet 18, followed by the cooling and solidification of this distal end. Forced cooling can also be used to cool the molten resin.

[0081] While the height dimension of each rivet head part 25 may be slightly smaller than the depth dimension of the rivet head receiving part 19a, the height dimension of the rivet head part 25 is preferably slightly larger (specifically, more than 100% of the depth dimension of the rivet head receiving part 19a and less than 105% of it) than the depth dimension of the rivet head receiving part 19a so that the rivet head part 25 protrudes slightly beyond the end surface 16a of the inter-pocket part 1a.

[0082] That is to say, assuming that the height dimension of the rivet head portion 25 is slightly less than the depth dimension of the rivet head receiving portion 19a as illustrated in Figures 9A and 9B, when the resin rivet 18 is pressed by the heated jig 43 so as to form the crimped head portion 26 (see [Fig. 8D]) as illustrated in [Fig. 9A], a base 53 supporting the rivet resin from below receives the end surface 16a of the inter-pocket part lia. At this point, since the end surface 29 of the rivet head part 25 is located (on the upper side in [Fig.9A]) axially towards the inside of the end surface 16a of the inter-pocket part 1a, an axial space is defined between the base 53 and the end surface 29 of the rivet head part 25. Therefore, when the resin rivet 18 is pressed by the heating jig 43 as illustrated in [Fig.9B], the resin rivet 18 is pushed in the axial direction by the amount of the space, and an axial space could thus be defined between the seat surface 27 of the rivet head part 25 and the lower surface 21a of the rivet head receiving part 19a.If the crimped head portion 26 is formed in this state, the following problem could occur: an axial gap occurs between the first annular body 8a and the other annular body 8b in the amount of the above gap, and the axially internal end surfaces 9a of the first annular body 8a and the axially internal end surfaces 9b of the other annular body 8b do not reliably come into close contact with each other.

[0083] On the other hand, if the height dimension of the rivet head portion 25 is slightly larger than the depth dimension of the rivet head receiving portion 19a, the rivet head portion 25 protrudes slightly beyond the end surface 16a of the inter-pocket portion 11a, and the base 53 receives the end surface 29 of the rivet head portion 25, so that no space is defined between the base 53 and the end surface 29 of the rivet head portion 25. Thus, when the resin rivet 18 is pressed by the heated jig 43, no axial space is defined between the seating surface 27 of the rivet head portion 25 and the lower surface 21a of the rivet head receiving portion 19a.When the crimped head receiving part 26 is formed in this state, there is no axial play between the first annular body 8a and the other annular body 8b, and the axially internal end surfaces 9a of the first annular body 8a and the axially internal end surfaces 9b of the other annular body 8b thus come into close and reliable contact with each other.

[0084] In this embodiment, a portion corresponding to the crimped head portion 26 is formed at the distal end of the resin rivet 18, and even after this portion is brought into contact with the lower surface 21b of the crimped head receiving portion 19b, by continuously pressing the heated template 43 against the distal end of the resin rivet 18, the crimped head portion 26 is fused and bonded to the inner surface of the crimped head receiving portion 19b (see [Fig. 8D]). While hot crimping is exemplified as a method for forming the crimped head portion 26, in which a resin is melted by pressing the high-temperature heated template 43 against the resin, a method such as ultrasonic crimping can be used, in which an ultrasonic vibration heating jig 43 (horn) is pressed against a resin so as to generate frictional heat, and the resin is melted by the frictional heat.

[0085] In the bearing of this embodiment, since, as illustrated in Figures 8A to 8D, each riveted head portion 26 is not formed before, but after, the insertion of the rivet shaft 24 into the rivet holes 17a and 17b, the rivet shaft 24 can be inserted into the rivet holes 17a and 17b before the riveted head portion 26, which is larger than the rivet holes 17a and 17b, is formed on the rivet shaft 24. Therefore, the rivet shafts 24 can be reliably inserted into the rivet holes 17a and 17b when the annular bodies 8a and 8b are superimposed on one another, so that the riveted head portions 26 can be formed on the rivet shafts 24 without spontaneous separation occurring between the annular bodies 8a and 8b. The annular bodies 8a and 8b can therefore be reliably coupled together.

[0086] Furthermore, in this bearing, each crimped head portion 26 is located in a position visible when the annular bodies 8a and 8b are mated together. Therefore, by visually checking whether or not the crimped head portion 26 has a shape that prevents it from protruding from the rivet hole 17b, it is easy to confirm whether or not the annular bodies 8a and 8b are fully mated together.

[0087] Furthermore, in this bearing, since, after the insertion of each rivet shaft 24 into the rivet holes 17a and 17b, the distal end of the rivet shaft 24 is cast to form the crimped head portion 26, the crimped head portion 26 can be formed to be sufficiently larger than the rivet holes 17a and 17b. It is thus possible to reliably couple the annular bodies 8a and 8b to each other.

[0088] Furthermore, as illustrated in Figures 1 to 3, since the axially external end surfaces 14a and 14b of the annular bodies 8a and 8b are not irregularly shaped, when the bearing is used in a high-speed rotational range, and lubricating oil is supplied from outside the bearing towards the axially external end surfaces 14a and 14b of the annular bodies, the lubricating oil is less likely to be dispersed and readily penetrates the bearing. A lack of lubricating oil is therefore less likely to occur, thus preventing seizing inside the bearing. In addition, the resistance to agitation of the lubricating oil can also be reduced, and the rolling torque can thus be lowered.

[0089] As illustrated in [Fig.8D], since the crimped head parts 26 are melted and bonded to the inner surfaces of the crimped head receiving parts 19b, the annular bodies 8a and 8b are reliably coupled together.

[0090] Moreover, in this bearing, given that, as illustrated in [Fig.4], when the annular bodies 8a and 8b are superimposed on each other, the recesses 34b of the other annular body 8b are fitted onto the respective projections 33a of the first annular body 8a, and the projections 33b of the other annular body 8b are fitted into the respective recesses 34a of the first annular body 8a, it is possible to achieve circumferential and radial positioning of the other annular body 8b relative to the first annular body 8a. Furthermore, when, during the operation of the bearing, a force (shear force) is applied, which causes the annular bodies 8a and 8b to slide circumferentially due to a misalignment of the rolling elements 4, the force is received by the projections 33a and 33b and the recesses 34a and 34b as well as the resin rivets 18 (see [Fig. 5]), and the shear force acting on the resin rivets 18 (see [Fig. 5]).5]) can thus be distributed, and breakage of the resin rivets 18 (see [Fig. 5]) can be avoided. As illustrated in [Fig. 7], since the annular bodies 8a and 8b have the same shape, common constituent elements can be used as annular bodies 8a and 8b.

[0091] Moreover, in this bearing, given that, as illustrated in [Fig. 10], the projections 33a and the recesses 34a are formed along the peripheral edges of the rivet holes 17a, and the projections 33b and the recesses 34b are formed along the peripheral edges of the rivet holes 17b, it is possible to reduce the space required to install the projections 33a and 33b and the recesses 34a and 34b.

[0092] Moreover, in the bearing, since, as illustrated in [Fig.4], the distal ends of the projections 33a and 33b are small, and the openings of the recesses 34a and 34b are large, when the annular bodies 8a and 8b are combined together, it is possible to easily fit the projections 33a into the recesses 34b, and also to easily fit the projections 33b into the recesses 34a.

[0093] Furthermore, since lubricating oil is retained in the oil reservoir grooves 40, a lack of lubricating oil can be prevented even when the amount of lubricating oil supplied from the outside is low.

[0094] Furthermore, as illustrated in [Fig. 1 1], since the groove width a of each oil reservoir groove 40 is less than the radial width b of the pocket 12, and also since the oil reservoir groove 40 is shallow, the lubricating oil can be effectively retained in the oil reservoir grooves 40 due to the surface tension action of the lubricating oil.

[0095] Moreover, since, as illustrated in [Fig. 10], the length d of each oil reservoir groove 40 viewed in the axial direction is long, it is possible to supply lubricating oil to sufficient areas of the surfaces of the rolling elements 4 (see [Fig. 3]).

[0096] As illustrated in [Fig. 6], each rivet shaft 24 can be formed into a column shape having a constant outside diameter along the entire length of the rivet shaft, but as illustrated in Figures 12 and 13, each rivet shaft 24 is preferably a stepped shaft having a large diameter (large diameter portion 24a) from the rivet head portion 25 to the axial center, and a small diameter (small diameter portion 24b) from the axial center to the distal end. A variant is described below in which each rivet shaft 24 is a stepped shaft.

[0097] As illustrated in [Fig. 12], the large-diameter portion 24a of each rivet shaft 24 is inserted (press-fitted) into the rivet shaft insertion hole 20a with interference fit. The outside diameter of the large-diameter portion 24a before insertion through the rivet shaft insertion hole 20a is greater than the inside diameter of the rivet shaft insertion hole 20a. The outside diameter of the large-diameter portion 24a before insertion through the rivet shaft insertion hole 20a can be set at 101 to 105% of the inside diameter of the rivet shaft insertion hole 20a. The small-diameter portion 24b of each rivet shaft 24 is inserted through the rivet shaft insertion hole 20b. The outside diameter of the small diameter part 24b is less than the inside diameter of the rivet shaft insertion hole 20b.The outside diameter of the small diameter 24b part can be fixed at 80 to 99% of the inside diameter of the rivet shaft insertion hole 20b.

[0098] If the rivet shafts 24 are stepped shafts as described above, before the bearing assembly, the resin rivets 18 are first press-fitted securely into the rivet holes 17a of an annular body 8a, and then the bearing can be assembled using the annular body 8a. That is, firstly, as illustrated in [Fig. 15], the resin rivets 18 are fixed to the annular body 8a by press-fitting the large-diameter portions 24a into the rivet shaft insertion holes 20a until the seating surfaces 27 of the rivet head portions 25 are in contact with the lower surfaces 21a of the rivet head receiving portions 19a of the first annular body 8a. Next, the rolling elements 4 are placed between the inner ring 1 and the outer ring 2 shown in [Fig. 2], and the rolling elements 4 are arranged at circumferentially equal intervals. Then, as shown in [Fig.

[15] , the annular bodies 8a and 8b are positioned so as to be axially opposed to each other, and so as to interpose the rolling elements 4 between them, the small diameter portions 24b of the resin rivets 18, press-fitted into the first annular body 8a, are inserted through the rivet shaft insertion holes 20b of the other annular body 8b, and the annular bodies 8a and 8b are superimposed one on top of the other. Then, as illustrated in Figures 8A to 8D, the crimped head portions 26, which prevent the... Resin rivets 18 are formed from rivet holes 17b, and annular bodies 8a and 8b are mated together.

[0099] If the bearing is assembled as described above, given that, as illustrated in [Fig. 15], the outside diameter of each large-diameter portion 24a before insertion through the rivet shaft insertion hole 20a is larger than the inside diameter of the rivet shaft insertion hole 20a, and that the large-diameter portion 24a is press-fitted securely into the rivet shaft insertion hole 20a, the resin rivets 18 inserted into the first annular body 8a never come out of the rivet holes. Thus, when the resin rivets 18 are inserted into the first annular body 8a as a previous step, for example, during transport of the assembly, the resin rivets 18 do not come out of the rivet holes 17a of the first annular body 8a.Furthermore, since the outer diameters of the small diameter 24b parts are smaller than the inner diameters of the rivet shaft insertion holes 20b, the small diameter 24b parts can be smoothly inserted through the rivet holes 17b of the other annular body 8b, thus improving bearing productivity.

[0100] In this variant, as illustrated in [Fig. 14], it is also possible to use rivet shafts 24 each tapered so that the outside diameter decreases from the rivet head part 25 towards the distal end.

[0101] [Second embodiment] Figures 16 to 20 illustrate a bearing in which a resin cage 5 according to a second embodiment of the present invention is used. The second embodiment differs from the first embodiment only in that, instead of projections 33a and recesses 34a, first stages 44a and second stages 45a are formed in the inter-pocket portions 11a of the annular body 8a, and instead of projections 33b and recesses 34b, first stages 44b and second stages 45b are formed in the inter-pocket portions 11b of the annular body 8b. The second embodiment is the same as the first embodiment in its other structures. Thus, the elements of the second embodiment corresponding to those of the first embodiment are designated by the same reference numerals, and their description is omitted.

[0102] As illustrated in [Fig. 19], in each inter-pocket portion 1a of the annular body 8a, radially extending first stages 44a and a radially extending second stage 45a are circumferentially spaced from each other, and in each inter-pocket portion 11b of the annular body 8b, a radially extending first stage 44b and a radially extending second stage 45b are circumferentially spaced from each other. More specifically, as illustrated in [Fig. 18], in each inter-pocket portion 1a of the annular body 8a, a radially extending first stage 44a, a radially extending second stage 45a, and a radially extending first stage 44a are formed in the order of 44a, 45a, and 44a from a circumferential side (side lower side (in Fig. 18) towards the other circumferential side (upper side in Fig. 18); and in each inter-pocket portion 11b of the other annular body 8b, a second stage 45b, a first stage 44b, and a second stage 45b are formed in the order 45b, 44b, and 45b from one circumferential side (lower side in Fig. 18) towards the other circumferential side (upper side in Fig. 18). In this embodiment, the other annular body 8b has the same shape as the first annular body 8a, and the other annular body 8b is arranged in a reversed orientation with respect to the first annular body 8a. That is to say that the second stages 45b of the other annular body 8b correspond to the first stages 44a of the first annular body 8a, and have the same shape as the first stages 44a.The first stages 44b of the other annular body 8b correspond to the second stages 45a of the first annular body 8a, and have the same shape as the second stages 45a.

[0103] Each first stage 44a, 44b is formed such that the other circumferential side (upper side in [Fig. 18]) of the first stage 44a, 44b projects axially from one circumferential side (lower side in [Fig. 18]) of the first stage 44a, 44b. Each second stage 45a, 45b is formed such that the other circumferential side (upper side in [Fig. 18]) of the second stage 45a, 45b retracts axially from one circumferential side (lower side in [Fig. 18]) of the second stage 45a, 45b. The structure of the first stages 44a and the second stages 45a of the first annular body 8a and its surroundings is described below. With regard to the first floors 44b and the second floors 45b of the other annular body 8b and their surroundings, elements corresponding to the surroundings are designated by the same reference numbers or by reference numbers with the alphabetic letter "a" at the end replaced by "b", and their description is omitted.

[0104] In each inter-pocket portion 1la of the first annular body 8a, a lower surface 46a, an upper surface 47a, a lower surface 48a and an upper surface 49a are formed in the order 46a, 47a, 48a and 49a from one circumferential side towards the other circumferential side (from the lower side to the upper side in [Fig. 18]). The lower surface 46a is connected to the inner pocket surface 13 on the first circumferential side (the lower side in [Fig. 18]) of the inter-pocket portion 1la, and extends towards the other circumferential side (the upper side in [Fig. 18]) thereof. The lower surface 46a is connected via the first floor 44a to the upper surface 47a, which is positioned to project axially relative to the lower surface 46a. The upper surface 47a extends from the first floor 44a to the other circumferential side (upper side on the [Fig.18]), and is connected via the second stage 45a to the lower surface 48a, which is positioned to retract axially relative to the upper surface 47a. The lower surface. 48a extends from the second floor 45a to the other circumferential side (upper side in [Fig. 18]), and is connected via the first floor 44a to the upper surface 49a, which is positioned to project axially relative to the lower surface 48a. The upper surface 49a extends from the first floor 44a to the other circumferential side (upper side in [Fig. 18]), and is connected to the inner pocket surface 13 on the other circumferential side (upper side in [Fig. 18]) of the inter-pocket portion 1a.

[0105] The lower surface 46a, the upper surface 47a, the lower surface 48a, and the upper surface 49a of each inter-pocket portion 1a are surfaces perpendicular to the axial direction. The lower surfaces 46a and 48a lie on the same plane. The upper surfaces 47a and 49a also lie on the same plane. One of the first stages 44a of each inter-pocket portion 1a rises at an angle such that the lower surface 46a and the first stage 44a form an obtuse angle. The first stage 44a can rise perpendicularly to the lower surface 46a. The second stage 45a of each inter-pocket portion 1a is formed on an imaginary radial straight line L1 connecting the center of the annular body and the center of the rivet hole 17a (see [Fig. 20]). The other first floor 44a rises at an angle so that the lower surface 48a and the other first floor 44a define an obtuse angle.The other first floor 44a can rise perpendicularly towards the lower surface 48a.

[0106] The intermediate axial positions of the first stages 44a of each inter-pocket part 1 la (the axial position at which the part between the axial position of the lower surface 46a and the axial position of the upper surface 47a is bisected, and the axial position at which the part between the axial position of the lower surface 48a and the axial position of the upper surface 49a is bisected) coincide with the intermediate axial position of the annular bodies 8a and 8b (the axial position at which the part between the axial position of the axially external end surface 14a of the first annular body 8a and the axial position of the axially external end surface 14b of the other annular body 8b is bisected) (see la [Fig. 17]).The axial intermediate position of the second stage 45a of each inter-pocket portion 1la (the axial position at which the portion between the axial position of the lower surface 48a and the axial position of the upper surface 47a is bisected) also coincides with the axial intermediate position of the annular bodies 8a and 8b. The axial length dimension of each of the first stages 44a is fixed at 10 to 20% of the axial width dimension of the inter-pocket portion 1la. The axial length dimension of the second stage 45a is fixed at 10 to 20% of the axial width dimension of the inter-pocket portion lia.

[0107] The first stages 44a of the first annular body 8a are engaged with the second stages 45b of the other annular body 8b. This engagement restricts the movement relative to the other annular body 8b with respect to the other circumferential side (upper side in [Fig. 18]) with respect to the first annular body 8a. Simultaneously, the second stages 45a of the first annular body 8a are engaged with the first stages 44b of the other annular body 8b. This engagement restricts the relative movement of the other annular body 8b (towards the lower side in [Fig. 18]) with respect to the first annular body 8a.

[0108] As illustrated in Figures 17 and 18, in the rolling of this embodiment, when the annular bodies 8a and 8b are combined together, the first stages 44a and the second stages 45a of the first annular body 8a are engaged with the second stages 45b and the first stages 44b of the other annular body 8b, and this engagement allows circumferential and radial positioning of the other annular body 8b relative to the first annular body 8a. Furthermore, when, during the operation of the bearing, a force (shear force) is applied, which causes the annular bodies 8a and 8b to slide circumferentially due to a misalignment of the rolling elements 4, the force is received by the first stages 44a and 44b and the second stages 45a and 45b as well as the resin rivets 18, and the shear force acting on the resin rivets 18 can thus be distributed, and the breakage of the resin rivets 18 can be prevented.Furthermore, since ring bodies 8a and 8b have the same shape, common constituent elements can be used as ring bodies 8a and 8b.

[0109] [Third embodiment] Figures 21 to 25 illustrate a bearing in which a resin cage 5 according to a third embodiment of the present invention is used. The second embodiment differs from the first embodiment only in that, instead of projections 33a and recesses 34a, stages 50a are formed in the inter-pocket portions 11a of the annular body 8a, and instead of projections 33b and recesses 34b, stages 50b are formed in the inter-pocket portions 11b of the annular body 8b. The third embodiment is identical to the first embodiment in its other structures. Thus, the elements of the third embodiment corresponding to those of the first embodiment are designated by the same reference numerals, and their description is omitted.

[0110] As illustrated in [Fig. 24], the number of pockets 12 in the annular bodies 8a and 8b is even (eight in [Fig. 24]). A single stage 50a extending in the radial direction is formed in each inter-pocket portion 1a. Stage 50a is formed on an imaginary radial straight line L1 connecting the center of the annular body and the center of the rivet hole 17a (see [Fig. 25]). Stages 50b having the same structure as the stages 50a in the inter-pocket portion 1a of the first annular body 8a are also formed in the respective inter-pocket portions 11b of the other annular body 8b. The other annular body 8b has the same shape that the first annular body 8a and the other annular body 8b are arranged in an orientation reversed with respect to the first annular body 8a. The structure of the 50a floors of the first annular body 8a and its surroundings is described below. With regard to the 50b floors of the other annular body 8b and its surroundings, corresponding elements are designated by the same reference numbers or by reference numbers with the letter "a" at the end replaced by "b", and their description is omitted.

[0111] The 50a floors of the first annular body 8a are formed so that the 50a floors of each circumferentially adjacent pair of inter-pocket parts 1 la between which the pocket-forming part 10a is located are symmetrical to each other in the circumferential direction. More specifically, as illustrated in [Fig. 23], the 50a level of an inter-pocket portion (lower side in [Fig. 23]) of each circumferentially adjacent pair of inter-pocket portions lia rises from a first circumferential side (lower side in [Fig. 23]) towards the other circumferential side (upper side in [Fig. 23]), and, via this 50a level, a lower surface 51a located on the first circumferential side (lower side in [Fig. 23]) and an upper surface 52a located on the other circumferential side (upper side in [Fig. 23]) are connected to each other. Furthermore, the 50a level of the other inter-pocket portion (upper side in [Fig. 23]) of each circumferentially adjacent pair of inter-pocket portions lia rises from a first circumferential side (lower side in [Fig. 23]) towards the other circumferential side (upper side in [Fig. 23]).23]) of each circumferentially adjacent pair of inter-pocket parts lia rises from the other circumferential side (upper side on the [Fig.23]) towards the circumferential side (lower side on the [Fig.23]), and, via this stage 50a, a lower surface 51a located on the other circumferential side (upper side on the [Fig.23]) and an upper surface 52a located on the first circumferential side (lower side on the [Fig.23]) are connected together. .

[0112] Each upper surface 52a is positioned to project axially from the intermediate axial position of the pair of annular bodies 8a and 8b (the axial position at which the portion between the axial position of the axially outer end surface 14a of the first annular body 8a and the axial position of the axially outer end surface 14b of the other annular body 8b is bisected). Each lower surface 51a is positioned to retract axially from the intermediate axial position of the pair of annular bodies 8a and 8b. The upper surfaces 52a are surfaces perpendicular to the axial direction. The upper surface 52a on the first circumferential side (lower side on [Fig.23]) and the upper surface 52a on the other circumferential side (upper side on [Fig.23]) with respect to each pocket-forming part 10a are located on the same plane.The lower surfaces 51a are surfaces perpendicular to the axial direction. The lower surface 51a on the first circumferential side (lower side on [Fig.23]) and the lower surface 51a on the other circumferential side. (upper side on the [Fig.23]) relative to each part of pocket formation 10a are located on the same plane.

[0113] As illustrated in [Fig. 22], the intermediate axial position of each stage 50a (the axial position at which the portion between the axial position of the upper surface 52a and the axial position of the lower surface 51a is bisected) coincides with the intermediate axial position of the pair of annular bodies 8a and 8b (the axial position at which the portion between the axial position of the axially external end surface 14a of the first annular body 8a and the axial position of the axially external end surface 14b of the other annular body 8b is bisected). The axial length of each stage 50a is fixed at 10 to 20% of the axial width dimension of the inter-pocket portion 1a.

[0114] The stages 50a of the first annular body 8a are engaged with the respective stages 50b of the other annular body 8b. This engagement restricts the relative circumferential movement between the annular bodies 8a and 8b.

[0115] In the rolling of this embodiment, when the annular bodies of the pair of annular bodies 8a and 8b are combined, the stages 50a of the first annular body 8a mesh with the respective stages 50b of the other annular body 8b, and this meshing allows circumferential and radial positioning of the other annular body 8b relative to the first annular body 8a. Furthermore, when, during the operation of the bearing, a force (shear force) is applied circumferentially, causing the annular bodies 8a and 8b to slide due to a misalignment of the rolling elements 4, the force is received by the stages 50a and 50b as well as the resin rivets 18, and the shear force acting on the resin rivets 18 can thus be distributed, and breakage of the resin rivets 18 can be prevented.Furthermore, since ring bodies 8a and 8b have the same shape, common constituent elements can be used as ring bodies.

[0116] The embodiments described above are merely examples in all respects, and the present invention is not limited to them. The scope of the present invention is indicated not by the above description, but by the claims, and is to be understood as including all modifications whose meaning and scope are equivalent to the scope of the claims.

[0117] DESCRIPTION OF REFERENCE NUMBERS 1: Inner ring 2: Outer ring 4: Rolling element 5: Resin cage 8a, 8b: Annular body 10a, 10b: Pocket formation section lia, 11b: Inter-pocket section 12: Pocket 13: Inner pocket surface 14a, 14b: Axially external end surface of the annular body 17a, 17b: Rivet hole 18: Resin rivet 19a: Rivet head receiving part 19b: Crimp head receiving section 24: Rivet tree 25: Rivet head part 26: Set head part 33a, 33b: Projection 34a, 34b: Obviously 37a, 37b: Outer peripheral surface of the projection 39a, 39b: Inner peripheral surface of the recess 40: Oil reservoir groove 41: Bottom of the inner pocket surface 43: Heated template 44a, 44b: First floor 45a, 45b: Second floor 50a, 50b: Floor a: Groove width of the oil reservoir groove b: Radial pocket width c: Oil reservoir groove depth d: Length of the oil reservoir groove viewed from the axial direction; e: Diameter of the rolling element

Claims

1. Demands Bearing comprising: an inner ring (1); an outer ring (2) arranged radially outwards from the inner ring (1); a plurality of rolling elements (4) arranged between the inner ring (1) and the outer ring (2); and a cage (5) retaining the rolling elements (4), in which the resin cage (5) is constituted by a pair of annular bodies (8a, 8b) axially opposed to each other, in which each of the annular bodies (8a, 8b) comprises: a plurality of pocket-forming parts (10a, 10b) circumferentially spaced from one another; and a plurality of inter-pocket parts (11a, 11b) are each formed between a corresponding circumferentially adjacent pair of pocket-forming parts (10a, 10b), and in which pockets (12) are defined between the pocket-forming parts (10a) of the first annular body (8a) of the pair of annular bodies (8a, 8b) and the respective pocket-forming parts (10b) of the other annular body (8b) of the pair of annular bodies (8a, 8b), and the rolling elements (4) are received in the respective pockets (12), characterized in that each of the annular bodies (8a, 8b) has a plurality of rivet holes (17a, 17b) extending axially through the respective inter-pocket parts (11a, 11b), in which the rivet holes (17a, 17b) of the annular bodies (8a, 8b) are arranged such that, with the annular bodies of the pair of annular bodies (8a, 8b) axially opposed to each other, circumferential positions of the rivet holes (17a) of the first annular body (8a) coincide with circumferential positions of the rivet holes (17b) of the other annular body (8b), in which the annular bodies of the pair of annular bodies (8a, 8b) are coupled to each other by a plurality of resin rivets (18) composed of a thermoplastic resin, and inserted through the rivet holes (17a, 17b) of the annular bodies (8a, 8b) in which the circumferential positions of the rivet holes (17a) of the first annular body (8a) coincide with the circumferential positions of the rivet holes (17b) of the other annular body (8b), and in which each of the resin rivets (18) comprises: a rivet shaft (24) inserted through one of the rivet holes (17a) of the first annular body (8a) and one of the rivet holes (17b) of the other annular body (8b); a rivet head portion (25) formed at one end of the rivet shaft (24), and axially engaging with the first annular body (8a); and a crimped head portion (26) formed by casting the other end of the rivet shaft (24), and axially engaging with the other annular body (8b).

2. Bearing according to claim 1, wherein an axially external end surface (14a, 14b) of each of the annular bodies (8a, 8b) comprises a flat surface extending circumferentially continuously around an entire circumference, wherein rivet head receiving parts (19a) are formed in the respective rivet holes (17a) of the first annular body (8a), and the rivet head parts (25) of the resin rivets (18) are received in the respective rivet head receiving parts (19a), and wherein crimped head receiving parts (19b) are formed in the respective rivet holes (17b) of the other annular body (8b), and the crimped head parts (26) of the resin rivets (18) are received in the respective crimped head receiving parts (19b).

3. Bearing according to claim 2, wherein the height dimensions of the rivet head parts (25) are larger than the depth dimensions of the rivet head receiving parts (19a).

4. Bearing according to claim 2 or 3, wherein the crimped head parts (26) are melted and bonded to the inner surfaces of the respective crimped head receiving parts (19b).

5. Bearing according to any one of claims 1 to 4, wherein each of the inter-pocket portions (1a, 11b) of each of the annular bodies (8a, 8b) has an axially projecting protrusion (33a, 33b) and an axially recessed protrusion (34a, 34b) which are formed in a row in a circumferential direction, and in which the recesses (34b) and the projections (33b) of the other annular body (8b) are fitted to the projections (33a) and the recesses (34a) of the first annular body (8a), respectively.

6. Bearing according to claim 5, wherein each of the projections (33a, 33b) of the annular bodies (8a, 8b) is formed such that one of the two semi-peripheral parts protrudes axially, the two semi-peripheral parts being defined by the bisection of a peripheral edge of a corresponding rivet hole of the rivet holes (17a, 17b), and wherein each of the recesses (34a, 34b) of the annular bodies (8a, 8b) is formed such that the other of the two semi-peripheral parts is axially recessed.

7. Bearing according to claim 5 or 6, wherein an external peripheral surface (37a, 37b) of each of the projections (33a, 33b) of the annular bodies (8a, 8b) is formed in a truncated semi-conical shape such that an external diameter thereof decreases in the direction of a distal end of the projection (33a, 33b), and wherein an internal peripheral surface (39a, 39b) of each of the recesses (34a, 34b) of the annular bodies (8a, 8b) is formed in a truncated semi-conical shape such that an internal diameter thereof decreases in the direction of a bottom of the recess (34a, 34b).

8. Bearing according to any one of claims 1 to 4, wherein each of the inter-pocket parts (1a, 11b) of each of the annular bodies (8a, 8b) has: a radially extending first stage (44a, 44b) formed such that the other circumferential side of the first stage (44a, 44b) protrudes axially from the first circumferential side of the first stage (44a, 44b); and a second radially extending stage (45a, 45b) formed such that the other circumferential side of the second stage (45a, 45b) retracts axially with respect to a circumferential side of the second stage (45a, 45b), the first radially extending stage (44a, 44b) and the second radially extending stage (45a, 45b) being circumferentially spaced from each other, and in which the first stages (44a) and the second stages (45a) of the first annular body (8a) are engaged with the second stages (45b) and the first stages (44b) of the other annular body (8b), respectively, so as to restrict the circumferential relative movement of the pair of annular bodies (8a, 8b).

9. A bearing according to any one of claims 1 to 4, wherein the number of pockets (12) is an even number, wherein a single radially extending stage (50a, 50b) is formed in each of the inter-pocket portions (11a, 11b) of the annular bodies (8a, 8b), wherein the stages (50a, 50b) of the annular bodies (8a, 8b) are formed such that the stages (50a, 50b) of each circumferentially adjacent pair of the inter-pocket portions (11a, 11b) between which a corresponding pocket-forming portion of the pocket-forming portions (10a, 10b) is situated are symmetrical to each other in a circumferential direction, and wherein the stages (50a) of the first annular body (8a) are meshed with the respective stages (50b) of the other annular body (8b) so as to restrict movement circumferential relative of the pair of annular bodies (8a, 8b).

10. Bearing according to any one of claims 1 to 9, wherein the rolling elements (4) are balls, wherein axially inner end surfaces of the pocket-forming parts (10a, 10b) of the annular bodies (8a, 8b) comprise inner pocket surfaces (13) having an axially concave hemispherical shape, and wherein each of the inner pocket surfaces (13) has an oil reservoir groove (40) extending towards both circumferential sides through a bottom (41) of the inner pocket surface (13).

11. Bearing according to claim 10, wherein a groove width a of each of the oil reservoir grooves (40) in the inner pocket surfaces (13) is fixed to a < (b / 2), where b is a radial width of one of the pockets (12), and wherein a depth c (mm) of each of the oil reservoir grooves (40) is fixed to c < 1.

0.

12. Bearing according to claim 10 or 11, wherein a length d of each of the oil reservoir grooves (40) when viewed axially is fixed at (e / 2) < d, where e is a diameter of one of the rolling elements (4).

13. A manufacturing method for a bearing, the bearing comprising: an inner ring (1); an outer ring (2) arranged radially outwards from the inner ring (1); a plurality of rolling elements (4) arranged between the inner ring (1) and the outer ring (2); and a cage (5) retaining the rolling elements (4), in which the resin cage (5) is constituted by a pair of annular bodies (8a, 8b) axially opposed to each other, in which each of the annular bodies (8a, 8b) comprises: a plurality of pocket-forming parts (10a, 10b) circumferentially spaced from one another; and a plurality of inter-pocket parts (11a, 11b) each formed between a corresponding circumferentially adjacent pair of pocket-forming parts (10a, 10b), in which pockets (12) are defined between the pocket-forming parts (10a) of the first annular body (8a) of the pair of annular bodies (8a, 8b) and the respective pocket-forming parts (10b) of the other annular body (8b) of the pair of annular bodies (8a, 8b), and the rolling elements (4) are received in the respective pockets (12), in which each of the annular bodies (8a, 8b) has a plurality of rivet holes (17a, 17b) extending axially through the respective inter-pocket parts (11a, 11b), in which the rivet holes (17a, 17b) of the annular bodies (8a, 8b) are arranged so that with the annular bodies of the pair of annular bodies (8a, 8b) axially opposed to each other, circumferential positions of the rivet holes (17a) of the first annular body (8a) coincide with circumferential positions of the rivet holes (17b) of the other annular body (8b), in which the annular bodies of the pair of annular bodies (8a, 8b) are coupled to each other by a plurality of resin rivets (18) composed of a thermoplastic resin, and inserted through the rivet holes (17a, 17b) of the annular bodies (8a, 8b) in which the circumferential positions of the rivet holes (17a) of the first annular body (8a) coincide with the circumferential positions of the rivet holes (17b) of the other annular body (8b), in which each of the resin rivets (18) comprises: a rivet shaft (24) inserted through one of the rivet holes (17a) of the first annular body (8a) and one of the rivet holes (17b) of the other annular body (8b); a portion of the rivet head (25) formed at one end of the rivet shaft (24), and axially engaging with the first annular body (8a); and a crimped head portion (26) formed by casting the other end of the rivet shaft (24), and axially engaging with the other annular body (8b), and in which the manufacturing process includes: a first step of superimposing the annular bodies (8a, 8b) one on top of the other, and of inserting the resin rivets (18) through the rivet holes (17a, 17b) of the annular bodies (8a, 8b); and a second step of forming, after the first step, the crimped head parts (26) by pressing a heated jig (43) against the other ends of the resin rivets (18), thus pushing and widening the other ends of the resin rivets (18) while heating and melting the other ends of the resin rivets (18).

Images