WO2023042492A1

WO2023042492A1 - Follower bearing

Info

Publication number: WO2023042492A1
Application number: PCT/JP2022/022340
Authority: WO
Inventors: 智昭中村
Original assignee: 日本トムソン株式会社
Priority date: 2021-09-14
Filing date: 2022-06-01
Publication date: 2023-03-23
Also published as: JP2023042227A

Abstract

This follower bearing comprises: an inner member having an annular first raceway surface on the outer circumferential surface thereof; an outer ring having, on the inner circumferential surface thereof, an annular second raceway surface facing the first raceway surface; and a plurality of rolling elements arranged on an annular raceway along the first raceway surface and the second raceway surface so as to be in contact with the first raceway surface and the second raceway surface. The outer ring includes an annular first member that is composed of steel, and an annular second member that does not contain reinforced fiber material, is composed of a crystalline thermoplastic resin, and covers the outer circumferential surface of the first member. The melt flow rate of the second member is 1 g/10 minutes to 10 g/10 minutes.

Description

follower bearing

The present disclosure relates to follower bearings. This application claims priority based on Japanese application No. 2021-149417 filed on September 14, 2021, and incorporates all the descriptions described in the Japanese application.

A follower bearing in which the outer ring rotates while being in contact with another member is known (see Patent Document 1, for example). The follower bearing disclosed in Patent Document 1 has an outer ring that includes a first member made of steel and a second member made of resin.

JP 2020-186783 A

In follower bearings, the second member arranged on the outer diameter side of the outer ring may crack due to, for example, long-term use or storage in a high-temperature environment. Since the second member of the outer ring of the follower bearing is in contact with other members, there is a demand for a follower bearing that is highly durable and can withstand long-term use while minimizing the occurrence of such cracks. Therefore, one of the objects is to provide a follower bearing that can withstand long-term use.

A follower bearing according to the present disclosure includes an inner member having an annular first raceway surface on its outer peripheral surface, an outer ring having an annular second raceway surface on its inner peripheral surface facing the first raceway surface, and a and a plurality of rolling elements arranged on an annular raceway along the first raceway surface and the second raceway surface so as to be in contact with the first raceway surface and the second raceway surface. The outer ring includes an annular first member made of steel and an annular second member made of crystalline thermoplastic resin without reinforcing fiber material and covering the outer peripheral surface of the first member. The melt flow rate of the second member is 1 g/10 minutes or more and 10 g/10 minutes or less.

The above follower bearing can withstand long-term use.

FIG. 1 is a schematic perspective view showing the structure of a follower bearing. FIG. 2 is a schematic cross-sectional view showing the structure of the follower bearing. FIG. 3 is a schematic perspective view showing the structure of the first member of the outer ring. FIG. 4 is a schematic cross-sectional view showing an enlarged region IV in FIG. FIG. 5 is a schematic cross-sectional view showing an enlarged region V in FIG. FIG. 6 is a graph showing the relationship between the load and the number of rotations in a follower bearing in which the second member contains a reinforcing fiber material and in a follower bearing in which the second member does not contain a reinforcing fiber material. FIG. 7 is a graph showing the relationship between the crack temperature of the outer ring and the estimated life time at low temperature. FIG. 8 is a schematic cross-sectional view showing a modification of the shape of the first member.

[Overview of embodiment]
The follower bearing of the present disclosure includes an inner member having an annular first raceway surface on its outer peripheral surface, an outer ring having an annular second raceway surface on its inner peripheral surface facing the first raceway surface, and a first raceway. and a plurality of rolling elements arranged on an annular raceway along the surface and the second raceway surface so as to be in contact with the first raceway surface and the second raceway surface. The outer ring includes an annular first member made of steel and an annular second member made of crystalline thermoplastic resin without reinforcing fiber material and covering the outer peripheral surface of the first member. The melt flow rate of the second member is 1 g/10 minutes or more and 10 g/10 minutes or less.

In the follower bearing of the present disclosure, the outer ring includes a second member made of crystalline thermoplastic resin that does not contain reinforcing fiber material. As a result, it is possible to suppress aggression against other members that come into contact with the outer ring and to suppress operating noise. Here, the inventors of the present application focused on the effects on the second member when the follower bearing is used for a long period of time or stored in a high-temperature environment. The inventors of the present application have made intensive studies on the cause of cracks occurring in the second member, and have found that the risk of cracks in the second member can be greatly reduced by adopting the following configuration. That is, since the second member is used in a situation where high loads are repeatedly applied, it contains additives such as reinforcing fiber materials such as glass fiber and carbon fiber in order to increase strength from the viewpoint of suppressing creep fracture. It is conceivable to let However, the inventor of the present application believes that if the second member contains the reinforcing fiber material, internal stress is generated in the second member due to the above-described usage pattern in the follower bearing, and peeling occurs between the reinforcing fiber material and the resin. thought it would start. Then, it is thought that cracks are generated starting from this peeling, and this crack progresses to lead to peeling of the surface layer portion, resulting in cracking. In other words, it was considered inappropriate to include a reinforcing fiber material in the second member included in the outer ring of the follower bearing. On the other hand, suppression of creep fracture must also be considered for the second member. In other words, the inventors thought that the outer ring used in the follower bearing should be configured so that the resin portion does not contain the reinforcing fiber material, and at the same time, the creep fracture of the outer ring should be suppressed to prevent cracks from occurring in the outer ring. In particular, when the outer ring having the above configuration is manufactured by insert molding, the resin is required to have good moldability. In other words, it was thought that if the moldability of the resin was not good, cracks due to peeling would become more pronounced.

Then, the inventors of the present application conducted further intensive studies and adopted a structure in which the second member has a melt flow rate of 1 g/10 minutes or more and 10 g/10 minutes or less in the above follower bearing. Thus, the second member made of a crystalline thermoplastic resin has a melt flow rate of 1 g/10 min or more and a melt flow rate of 10 g/10 min or less, thereby reducing the molecular weight while improving moldability. It can be kept moderately high to suppress creep fracture. Therefore, such follower bearings can withstand long-term use. In the present disclosure, "resin" includes rubber. That is, the second member may be made of rubber. The melt flow rate (MFR) is specified in ISO1133.

In the follower bearing described above, the resin constituting the second member may be at least one resin selected from the group consisting of polyamide, polyacetal, polyphenylene sulfide, polyamideimide, polyimide, polyetheretherketone and polyurethane. Polyamide, polyacetal, polyphenylene sulfide, polyamideimide, polyimide, polyetheretherketone, and polyurethane are suitable as the resin constituting the second member.

In the follower bearing described above, the axial end of the first member may be covered with the second member. By doing so, it is possible to reduce the possibility that the first member and the second member are separated in the axial direction. Therefore, it can withstand use for a longer period of time.

In the follower bearing described above, the axial end face of the second member may be flat. By doing so, for example, at the time of insert molding, the formation of welds due to the formation of concave portions and convex portions on the axial end face of the second member is suppressed. Therefore, creep fracture can be further suppressed, cracks appearing on the axial end face of the second member can be suppressed, and the second member can be used for a longer period of time.

In the follower bearing described above, the resin forming the second member may be a copolymer polyacetal. Such a resin is suitable as a resin constituting the second member included in the follower bearing from the viewpoint of elastic modulus and fatigue strength, as well as from the viewpoint of cost. Copolymer acetals include, for example, copolymers of formaldehyde and oxyethylene.

In the above follower bearing, the melt flow rate of the second member may be 2.5 g/10 minutes or more and 9 g/10 minutes or less. By doing so, the fatigue life of the outer ring can be lengthened. Therefore, a long life can be achieved more reliably.

In the follower bearing, the rolling elements may be rollers. By doing so, it becomes easy to achieve a sufficient load resistance while suppressing the cross-sectional height of the follower bearing.

[Specific example of embodiment]
Next, an example of specific embodiments of the follower bearing of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is a schematic perspective view showing the structure of a follower bearing according to one embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view showing the structure of the follower bearing. FIG. 2 is a cross-sectional view taken along a plane including the rotation axis of the follower bearing. FIG. 3 is a schematic perspective view showing the structure of the first member of the outer ring. FIG. 4 is a schematic cross-sectional view showing an enlarged region IV in FIG. FIG. 5 is a schematic cross-sectional view showing an enlarged region V in FIG.

1 to 5, follower bearing 1 in the present embodiment includes shaft member 30 as an inner member, outer ring 60, a plurality of rollers 70 as rolling elements, and a holding member for holding rollers 70. a vessel 80; In addition, in FIG. 2, the rotating shaft 31, which is the central axis of the shaft member 30, is illustrated with a dashed line.

The shaft member 30 includes a rod-shaped (solid cylindrical) main body 10 , a flange 12 formed at one end of the main body 10 and having a diameter larger than that of the main body 10 , and an outer peripheral surface of the main body 10 . and a side plate 20 which is a ring coaxially installed on the main body 10 so as to partially surround it in the circumferential direction. The body portion 10 has a first end face 13 that is one end in the axial direction and a second end face 15 that is the other end opposite to the first end face 13 . Both the first end surface 13 and the second end surface 15 have a circular planar shape.

A hexagonal hole 13A having a regular hexagonal prism shape is formed in a region of the first end face 13 including a region that intersects with the rotation shaft 31 that is the central axis of the shaft member 30 . A threaded portion 14 having a helical thread groove is arranged in a region including the end (the other end) of the body portion 10 on the side of the second end face 15 . With this structure, when installing the follower bearing 1, for example, the threaded portion 14 is screwed into a threaded hole (not shown) formed in a holding member that holds the follower bearing 1, and a hexagonal wrench is inserted into the hexagonal hole 13A. The follower bearing 1 can be fixed to the holding member by inserting and tightening a part of the shaft member 30 through the housing hole and screwing a nut onto the threaded portion 14 .

The body portion 10 is arranged between a solid cylindrical shaft portion 17 including a threaded portion 14 and a region where the shaft portion 17 and the flange portion 12 are located in the axial direction, and has a larger diameter than the shaft portion 17 . and diameter 16 . The diameter of the large diameter portion 16 is smaller than the diameter of the collar portion 12 . A first raceway surface 11 having a cylindrical shape is formed on the outer peripheral surface of the large diameter portion 16 . That is, the shaft member 30 has the annular first raceway surface 11 on the outer peripheral surface. In the present embodiment, the first raceway surface 11 has an annular shape whose center axis coincides with that of the first raceway surface 11 , is arranged on one side of the first raceway surface 11 in the axial direction, and extends radially from the outer circumference of the main body portion 10 . The first convex portion that protrudes outward is the collar portion 12 . The outer periphery of the body portion 10 in the region where the collar portion 12 is located is illustrated by broken lines in FIGS.

The annular side plate 20 has a first end surface 23 as one end surface, a second end surface 24 as the other end surface, an outer peripheral surface 21 and an inner peripheral surface 22 . The first end surface 23 and the second end surface 24 are parallel. The outer peripheral surface 21 and the inner peripheral surface 22 are concentric cylindrical surfaces. The side plate 20 is arranged so that the first end surface 23 is in contact with the stepped surface 16A (see FIGS. 2 and 5), which is the end surface (stepped portion) of the large diameter portion 16 on the shaft portion 17 side in the axial direction. The side plate 20 has an inner diameter (diameter of the inner peripheral surface 22 ) corresponding to the outer diameter of the shaft portion 17 . The side plate 20 is press-fitted onto the shaft portion 17 and fixed to the shaft portion 17 . In the present embodiment, the first raceway surface 11 has an annular shape whose center axis coincides with that of the first raceway surface 11 , is arranged on the other side in the axial direction with respect to the first raceway surface 11 , and extends radially from the outer circumference of the main body portion 10 . The second protrusion projecting outward is the side plate 20 . The shaft member 30 is made of steel such as carbon steel for machine structural use, alloy steel for machine structural use, or bearing steel. A region of the shaft member 30 that includes at least the first raceway surface 11 of the body portion 10 may be hardened by quenching. Moreover, part or the whole of the side plate 20 may be hardened by quenching.

The outer ring 60 has an annular second raceway surface 41 facing the first raceway surface 11 on its inner peripheral surface. Outer ring 60 includes first member 40 and second member 50 . The first member 40 has a hollow cylindrical shape and includes a tubular portion 42 including the second raceway surface 41 and a protrusion 43 extending radially outward from the tubular portion 42 . The first member 40 is made of steel. As the steel constituting the first member 40, for example, mild steel, carbon steel for machine structural use, alloy steel for machine structural use, or the like can be adopted. Also, the first member 40 may be hardened by quenching. The first member 40 may be formed by pressing or drawing using a steel plate made of mild steel, for example.

The cylindrical portion 42 has a second raceway surface 41 that is an inner peripheral surface, an outer peripheral surface 44A, a first end surface 45A that is one end surface in the axial direction, and the other end portion 46 in the axial direction. ing. The first member 40 includes a second raceway surface 41 . The first end surface 45A of the first member 40 and the collar portion 12 face each other. That is, the collar portion 12 and the first member 40 face each other in the axial direction.

The projecting portion 43 is connected to the other axial end portion 46 of the cylindrical portion 42 . The protrusion 43 is plate-shaped. The projecting portion 43 has an annular shape that is continuous over the entire circumferential direction of the first member 40 . The projecting portion 43 has a second end surface 45B which is the other end surface in the axial direction, an outer peripheral surface 44B, and a side surface 45C located on the opposite side of the second end surface 45B in the axial direction. The boundary between the end portion 46 and the protrusion 43 is illustrated by dashed lines in FIGS. The second end surface 45B and the first end surface 23 of the side plate 20 face each other. That is, the side plate 20 and the first member 40 face each other in the axial direction.

A notch 47 that is recessed radially inward is formed in the protrusion 43 (see FIG. 3 in particular). A plurality of notches 47 are formed at intervals in the circumferential direction. The notch 47 is formed so as to penetrate the plate-like protrusion 43 in the thickness direction.

The second member 50 has an annular shape. The second member 50 is made of a crystalline thermoplastic resin that does not contain reinforcing fiber material. That is, the second member 50 does not contain glass fibers and carbon fibers. The resin forming second member 50 may be at least one resin selected from, for example, the group of polyamide, polyacetal, polyphenylene sulfide, polyamideimide, polyimide, polyetheretherketone, and polyurethane. The second member 50 is arranged coaxially with the first member 40 . The second member 50 covers the entire outer

peripheral surfaces

44A and 44B of the first member 40 . The second member 50 also covers the first end surface 45A, the second end surface 45B and the side surface 45C of the first member 40. As shown in FIG. That is, both sides of the protrusion 43 in the axial direction are filled with the second member 50 .

The second member 50 has an inner peripheral surface 51, an outer peripheral surface 52, a first end surface 53A, and a second end surface 53B. 53 A of 1st end surfaces and the 2nd end surface 53B are each a plane. That is, both the first end surface 53A and the second end surface 53B, which are the end surfaces in the axial direction of the second member 50, are flat and have a shape in which no recesses or protrusions are provided. The second member 50 has a first portion 54A that has an annular shape whose central axis coincides with the first raceway surface 11 and that enters between the first member 40 and the flange portion 12 that is the first convex portion. contains. The first portion 54A is formed over the entire circumference of the inner peripheral surface 51 . Further, the second portion 54B, which has an annular shape whose central axis coincides with the first raceway surface 11, and which enters between the side plate 20, which is the second convex portion, and the first member 40, is disposed on the second member 50. contains. The second portion 54B is formed over the entire circumference of the inner peripheral surface 51 . That is, the axial end of the first member 40 is covered with the second member 50 . Furthermore, although not shown, the second member 50 also enters the notch 47 described above.

The retainer 80 has an annular shape. In this embodiment, retainer 80 is made of steel, but a resin retainer can also be used. Cage 80 is arranged concentrically with shaft member 30 and outer ring 60 in a space sandwiched between shaft member 30 and outer ring 60 . A plurality of pockets 81 are arranged in the retainer 80 at regular intervals in the circumferential direction. One roller 70 is arranged in each of the plurality of pockets 81 . By being held by the retainer 80 in this way, the plurality of rollers 70 are arranged on the first raceway surface 11 and the second raceway surface 41 on an annular raceway along the first raceway surface 11 and the second raceway surface 41 . placed in contact. The roller 70 has a solid cylindrical shape. The roller 70 has a cylindrical outer peripheral surface 71 and a pair of spherical end surfaces 72 . The end face 72 of the roller 70 may be flat. The rollers 70 are in contact with the first raceway surface 11 and the second raceway surface 41 on the outer peripheral surface 71 . The rollers 70 consist of steel, for example bearing steel. The rollers 70 may be quench hardened.

The second member 50 includes a first region 58A that faces the flange portion 12, which is the first convex portion, in the axial direction. The first region 58A is included in the first portion 54A. In the first region 58A, a first seal portion 59A having an annular shape whose center axis coincides with the first raceway surface 11 and protruding in the axial direction toward the flange portion 12 is formed. The first seal portion 59A is in contact with the collar portion 12 at its tip. In this embodiment, a plurality, more specifically, two (double-lipped) first seal portions 59A are radially spaced apart from each other.

The second member 50 includes a second region 58B facing the side plate 20, which is the second protrusion, in the axial direction. The second region 58B is included in the second portion 54B. In the second region 58B, a second seal portion 59B having an annular shape whose center axis coincides with that of the first raceway surface 11 and protruding axially toward the side plate 20 is formed. The second seal portion 59B is in contact with the side plate 20 at its tip. In this embodiment, a plurality, more specifically two (double lip) second seal portions 59B are arranged radially spaced apart from each other. That is, in the present embodiment, the first seal portion 59A and the second seal portion 59B are arranged so as to close both axial ends of the space between the shaft member 30 and the outer ring 60 . The first seal portion 59A and the second seal portion 59B are part of the second member 50 and are formed integrally with the second member 50 .

The outer ring 60 having such a configuration can be manufactured, for example, as follows. For example, the first member 40 configured as described above is prepared and placed in a mold cavity in advance. Next, resin is injected into the cavity. Insert molding is performed in this way, and the outer ring 60 in which the first member 40 and the second member 50 are integrated is molded.

In follower bearing 1 of the above embodiment, shaft member 30 , outer ring 60 , retainer 80 , and plurality of rollers 70 are arranged as described above, so that outer ring 60 is relatively rotated with respect to shaft member 30 in the circumferential direction. can be rotated to

In the follower bearing 1 of the above embodiment, the outer ring 60 includes the second member 50 made of crystalline thermoplastic resin containing no reinforcing fiber material. As a result, it is possible to suppress aggression against other members that come into contact with the outer ring and to suppress operating noise. In addition, the frequency of supplying the lubricant between the outer peripheral surface 52 of the outer ring 60 and the other member can be reduced, or the supply of the lubricant can be eliminated. This makes it possible to achieve reduced maintenance or maintenance-free operation. From this point of view, it is preferable to employ a self-lubricating resin, such as polyacetal, as the resin forming the second member 50 . By abolishing the supply of a lubricant, it becomes easier to apply to applications where it is desired to prevent oil scattering, such as food manufacturing and processing equipment, medical equipment, semiconductor manufacturing equipment, and the like. Further, since the outer ring 60 is made of a crystalline thermoplastic resin that does not contain reinforcing fiber material and includes the second member 50, it is possible to suppress the occurrence of rust at the contact portion with the other member. As a result, since the second member 50 does not rust, it is possible to prevent the mating member that contacts the second member 50 from rusting. In addition, dust generation due to scattering of rust is suppressed, and application to applications where suppression of dust generation is desired, such as semiconductor manufacturing equipment and electronic component manufacturing equipment, is facilitated. In addition, since the outer ring 60 includes the second member 50 made of resin, it is possible to improve the chemical resistance of the contact portion with the other member.

Then, the second member made of a crystalline thermoplastic resin has a melt flow rate of 1 g/10 min or more and a melt flow rate of 10 g/10 min or less, so that the molecular weight is moderated while improving the moldability. can be kept high to suppress creep rupture. That is, the moldability can be improved by setting the melt flow rate to 1 g/10 minutes or more. Further, by setting the melt flow rate to 10 g/10 minutes or less, the molecular weight can be kept moderately high, and creep fracture can be suppressed. Therefore, such follower bearings can withstand long-term use. Further, the fatigue life of the outer ring can be lengthened by setting the melt flow rate of the second member 50 to 2.5 g/10 minutes or more and 9 g/10 minutes or less. Therefore, a long life can be achieved more reliably.

FIG. 6 is a graph showing the relationship between the load and the number of rotations in the follower bearing when the second member contains the reinforcing fiber material and in the follower bearing when the second member does not contain the reinforcing fiber material. FIG. 6 is a so-called SN diagram, in which the vertical axis indicates the load (N (Newton)) and the horizontal axis indicates the number of revolutions (10,000 revolutions). In FIG. 6, open diamonds indicate the case of PPS (polyphenylene sulfide) containing CF (carbon fiber), and open triangles indicate the case of PA9T containing GF (glass fiber (glass fiber)). Polyamide 9T), an open circle indicates the case of PEEK (polyetheretherketone) containing CF, and an open square indicates the case of PA4T (polyamide 4T) containing GF. That is, the outline shape is the second member including the reinforcing fiber material. On the other hand, hatched squares indicate the case of POM (polyacetal) containing no reinforcing fiber material and having a melt flow rate of 2.5 g/10 min. The case of POM with a rate of 20 g/10 min is shown, and the solid circle shows the case of PEEK with no reinforcing fiber material and a melt flow rate of 5 g/10 min.

With reference to FIG. 6, in the case of the second member made of resin containing reinforcing fiber material, the number of rotations is 50 or less, and the life tends to be short. On the other hand, in the case of the second member made of resin that does not contain reinforcing fiber material, it can be understood that 1,000,000 rotations or more can be achieved, and a long life is achieved.

FIG. 7 is a graph showing the relationship between the crack temperature of the outer ring and the estimated life time at low temperatures. In FIG. 7, the vertical axis indicates temperature (° C.), and the horizontal axis indicates expected life time (hours). In FIG. 7, the straight line indicates the case where the result of the accelerated test with a melt flow rate of 20 g/10 minutes is applied to the assumed time of double speed at 10 ° C. based on the empirical rule, and the x mark indicates POM not containing the reinforcing fiber material. and the melt flow rate is 20 g/10 minutes, and ◯ indicates the case where the POM does not contain reinforcing fiber material and the melt flow rate is 2.5 g/10 minutes. The X mark plots the time when the outer ring cracked, and the ◯ mark plots the time when the outer ring has not yet cracked. Here, 95° C. is used as the temperature for the accelerated test.

With reference to FIG. 7, when the melt flow rate was 20 g/10 minutes, cracks occurred after 300 hours at 95°C. With regard to this, when applied to double speed at 10°C, destruction occurs in about 7 months at 50°C. On the other hand, when the melt flow rate is 2.5 g/10 minutes, it can be understood that cracks do not occur even after 1936 hours at 95°C. Regarding this, it can be understood that when applied to double speed at 10° C., it is durable at 50° C. for 60 months or more.

As described above, the follower bearing 1 can withstand long-term use.

In addition, in the follower bearing 1 of the above embodiment, the axial end of the first member 40 is covered with the second member 50 . Therefore, it is possible to reduce the possibility that the first member 40 and the second member 50 are separated in the axial direction. Therefore, such a follower bearing 1 is a follower bearing that can withstand use for a longer period of time.

In the follower bearing 1 of the above embodiment, the axial end surface of the second member 50 is flat. Therefore, the formation of welds due to the formation of recesses and protrusions on the axial end face of the second member 50 is suppressed. Therefore, such a follower bearing 1 can further suppress creep fracture, suppress the occurrence of cracks appearing on the axial end face of the second member 50, and can withstand use for a longer period of time. bearing.

In the follower bearing 1 of the above-described embodiment, the first member 40 has a hollow cylindrical shape and includes a tubular portion 42 including the second raceway surface 41 and a protrusion extending radially outward from the tubular portion 42. 43 and . Both sides of the protrusion 43 in the axial direction are filled with the second member 50 . Therefore, it is possible to reduce the possibility that the first member 40 and the second member 50 are separated in the axial direction. Therefore, such a follower bearing 1 is a follower bearing capable of improving reliability.

In the follower bearing 1 of the above embodiment, the protrusion 43 is connected to the axial end 46 of the tubular portion 42 . Therefore, the first member 40 having the projecting portion 43 having such a configuration can be easily manufactured using press working, drawing work, or the like. The shape of the projecting portion 43 is not limited to the above-described embodiment. For example, a shape in which the projecting portion 43 is bent radially outward and then folded back toward the outer peripheral surface 44A of the cylindrical portion 42 can be selected as appropriate. . In addition, the protrusions 43 may be formed at both ends of the cylindrical portion 42 in the axial direction.

In the follower bearing 1 of the above embodiment, the protrusion 43 has an annular shape that is continuous over the entire circumferential direction of the first member 40 . The follower bearing 1 including the first member 40 having such a configuration is a follower bearing that can further reduce the risk of the first member 40 and the second member 50 separating in the axial direction.

In the follower bearing 1 of the above embodiment, the projection 43 is formed with a notch 47 that is recessed radially inward. Therefore, the second member 50 can enter the notch 47 . Therefore, such a follower bearing 1 is a follower bearing capable of restricting relative rotation of the first member 40 with respect to the second member 50 .

In the follower bearing 1 of the above embodiment, a plurality of notches 47 are formed at intervals in the circumferential direction. Therefore, such a follower bearing 1 is a follower bearing that can further restrict the relative rotation of the first member 40 with respect to the second member 50 .

Note that the follower bearing 1 of the above-described embodiment may have a configuration that does not include the projecting portion 43, as shown in FIG. FIG. 8 is a schematic cross-sectional view showing a modification of the shape of the first member. That is, the first member 40 included in the outer ring 60 of the follower bearing 1 in this case has a hollow cylindrical shape and is composed of a tubular portion 42 including the second raceway surface 41 . In the follower bearing 1 having such a configuration, the shape of the first member 40 can be made simpler.

In the follower bearing 1 of the above embodiment, the first seal portion 59A and the second seal portion 59B protrude in the axial direction. Therefore, in the follower bearing 1 of the above embodiment, when a load is applied in the radial direction, compared to the case where the first seal portion 59A and the second seal portion 59B protrude in the radial direction, the This is a follower bearing capable of suppressing an increase in rotational torque due to contact between each of the first seal portion 59A and the second seal portion 59B and the shaft member 30, which is an inner member, in the radial direction, thereby stabilizing the rotational torque. ing. Furthermore, leakage of lubricant such as grease from the inside of the bearing (the space between the shaft member 30 and the outer ring 60) and entry of foreign matter into the bearing from the outside can be suppressed.

In the follower bearing 1 of the above embodiment, a plurality of the first seal portions 59A and the second seal portions 59B are formed at intervals in the radial direction. Therefore, the plurality of first seal portions 59A and the plurality of second seal portions 59B can further suppress the entry of foreign matter into the bearing and the leakage of grease or the like to the outside of the bearing. Therefore, such a follower bearing 1 is a follower bearing capable of improving the sealing functions of the first seal portion 59A and the second seal portion 59B.

In the follower bearing 1 of the above-described embodiment, the shaft member 30 has a body portion 10 including the first raceway surface 11 and an annular shape whose central axis coincides with the first raceway surface 11. 11 , and includes a flange portion 12 as a first convex portion that protrudes radially outward from the outer periphery of the main body portion 10 . The second member 50 includes a first portion 54</b>A that has an annular shape whose center axis coincides with the first raceway surface 11 and that enters between the flange portion 12 and the first member 40 . Therefore, such a follower bearing 1 is a follower bearing that can avoid axial contact between the flange portion 12 and the first member 40 .

In the follower bearing 1 of the above embodiment, it has an annular shape whose central axis coincides with the first raceway surface 11 , is arranged on the other side in the axial direction with respect to the first raceway surface 11 , and The shaft member 30 includes a side plate 20 as a second projection projecting radially outward from the outer periphery. The second member 50 includes a second portion 54</b>B having an annular shape whose center axis coincides with the first raceway surface 11 and which enters between the side plate 20 and the first member 40 . Therefore, such a follower bearing 1 is a follower bearing that can avoid contact between the side plate 20 and the first member 40 in the axial direction.

In the above embodiment, the follower bearing 1 includes the first seal portion 59A and the second seal portion 59B projecting in the axial direction. 50 may include a region facing shaft member 30 . A seal portion having an annular shape whose center axis coincides with the first raceway surface 11 and protruding toward the shaft member 30 may be formed in a region facing the shaft member 30 . By doing so, it is possible to suppress the intrusion of foreign matter into the bearing and the leakage of grease or the like to the outside of the bearing. Moreover, the number of parts can be reduced as compared with the case where a separate sealing member is arranged between the outer ring and the inner member. For example, the follower bearing 1 may include a radially projecting first seal portion and a second seal portion. Specifically, the follower bearing 1 contacts the inner peripheral surface 51 of the second member 50, and the outer peripheral surface 12A of the flange portion 12, which is the outer peripheral surface of the shaft member 30, and the outer peripheral surface 21 of the side plate 20 at the tip. A seal portion 59A and a second seal portion 59B may be formed. As a result, the number of parts can be reduced compared to the case where a separate seal member is arranged between the outer ring 60 and the shaft member 30 . In addition, since the first seal portion 59A and the second seal portion 59B are integrated with the second member 50, the seal member does not come off due to excessive supply of grease or the like, as in the case where a separate seal member is arranged. can be avoided. As described above, the follower bearing 1 of the above-described embodiment is a follower bearing capable of suppressing aggression toward other members in contact with the outer ring 60 and suppressing operating noise while reducing the number of parts. It has become.

In the follower bearing described above, the resin constituting the second member 50 is not particularly limited, and a resin having appropriate wear resistance, hardness, etc., can be adopted according to the application. Specifically, for example, it may be at least one resin selected from the group consisting of polyamide, polyacetal, polyphenylene sulfide, polyamideimide, polyimide, polyetheretherketone and polyurethane. Polyamide, polyacetal, polyphenylene sulfide, polyamide-imide, polyimide, polyetheretherketone, and polyurethane are suitable as the resin forming the second member 50 . Also, rubber (including natural rubber and synthetic rubber) may be employed as the resin forming the second member 50 .

In the follower bearing described above, the resin forming the second member may be a copolymer polyacetal. Such a resin is suitable as a resin constituting the second member included in the follower bearing from the viewpoint of elastic modulus and fatigue strength, as well as from the viewpoint of cost. Copolymer acetals include, for example, copolymers of formaldehyde and oxyethylene. Regarding the determination of whether it is a copolymer, for example, FT-IR (Fourier Transform-Infrared Spectroscopy), NMR (Nuclear Magnetic Resonance), mass spectrometry, etc. are performed to determine whether it is a copolymer. be able to.

In addition, in the above embodiment, the case where the rollers 70 are employed as the rolling elements of the follower bearing 1 has been described, but balls may be employed as the rolling elements. Moreover, in the above embodiment, the case where the rolling elements are arranged in a single row has been described, but they may be arranged in a double row. Moreover, in the above-described embodiment, the case where the solid shaft member 30 is employed as the inner member has been described, but a bearing ring (inner ring), for example, may be employed as the inner member. Further, the second member 50 can be appropriately selected from a hollow cylindrical shape, a spherical outer peripheral surface, and the like.

In the above embodiment, the first seal portion 59A and the second seal portion 59B have a shape that tapers toward the tip as shown in FIGS. ), the shape of the seal portion is not limited to this, and any appropriate shape can be adopted according to the application. As the seal portion, a first seal portion and a second seal portion having an arc-shaped surface in a cross section including the rotating shaft of the follower bearing may be employed. As the seal portions, a lip-shaped first seal portion and a second lip-shaped seal portion projecting radially outward from the inner peripheral surface 51 of the second member 50 in a cross section including the rotating shaft of the follower bearing are adopted. may be Further, in the above embodiment, the case where the first seal portion 59A and the second seal portion 59B respectively come into contact with the shaft member 30, which is an inner member, is described. It may be non-contact. Also, although two first seal portions 59A and two second seal portions 59B are provided, the number of the first seal portions 59A and the number of the second seal portions 59B is not limited to one or three or more. can be adopted.

In the present disclosure, a follower bearing refers to a bearing that rotates in the circumferential direction relative to the shaft member while the outer ring is in contact with another member while the shaft member is fixed. The other member is not particularly limited, and may be, for example, a cam, a rail, or a belt.

In addition, in the above embodiment, the second member may contain a solid lubricant such as a white pigment. By doing so, it is possible to improve the appearance and the like.

It should be understood that the embodiments disclosed this time are illustrative in all respects and not restrictive in any aspect. The scope of the present invention is defined by the scope of the claims rather than the above description, and is intended to include all changes within the meaning and scope of equivalence to the scope of the claims.

1 follower bearing, 10 main body, 11 first raceway surface, 12 flange, 12A outer peripheral surface, 13, 45A first end surface, 13A hexagonal hole, 14 threaded portion, 15 second end surface, 16 large diameter portion, 16A stepped surface , 17 shaft portion, 20 side plate, 21 outer peripheral surface, 22 inner peripheral surface, 23 first end face, 24 second end face, 30 shaft member (inner member), 31 rotating shaft, 40 first member, 41 first raceway surface , 42 cylindrical portion, 43 protrusion, 44A, 44B outer peripheral surface, 45A first end surface, 45B second end surface, 45C side surface, 46 end portion, 50 second member, 51 inner peripheral surface, 52 outer peripheral surface, 53A first End face 53B Second end face 54A First portion 54B Second portion 57 Wall surface

58A First region

58B Second region 59A First seal portion 59B Second seal portion 60 Outer ring 70 Roller 71 Periphery face, 72 end face, 80 retainer, 81 pocket.

Claims

an inner member having an annular first raceway surface on its outer peripheral surface;
an outer ring having an annular second raceway surface facing the first raceway surface on its inner peripheral surface;
a plurality of rolling elements arranged on an annular raceway along the first raceway surface and the second raceway surface so as to be in contact with the first raceway surface and the second raceway surface;
The outer ring is
a toric first member made of steel;
an annular second member made of a crystalline thermoplastic resin that does not contain a reinforcing fiber material and covering the outer peripheral surface of the first member;
The follower bearing, wherein the second member has a melt flow rate of 1 g/10 minutes or more and 10 g/10 minutes or less.
2. The follower bearing according to claim 1, wherein the resin constituting said second member is at least one resin selected from the group consisting of polyamide, polyacetal, polyphenylene sulfide, polyamideimide, polyimide, polyetheretherketone and polyurethane. .
The follower bearing according to claim 1 or claim 2, wherein the axial end of the first member is covered with the second member.
The follower bearing according to any one of claims 1 to 3, wherein the axial end surface of the second member is flat.
The follower bearing according to any one of claims 1 to 4, wherein the resin constituting the second member is a copolymer polyacetal.
The follower bearing according to any one of claims 1 to 5, wherein the second member has a melt flow rate of 2.5 g/10 minutes or more and 9 g/10 minutes or less.
The follower bearing according to any one of claims 1 to 6, wherein said rolling elements are rollers.