JP2017020602A - Hub unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make one of a portion made of light alloy and a portion made of steel less likely to be affected by heat from the other when a member is manufactured in a case where one portion of the member forming a hub unit is made of the light alloy and the other is made of the steel.SOLUTION: A hub unit (10) includes an outer ring (12), an inner shaft (14), and rolling elements (18, 20). The inner shaft is arranged so as to rotate relative to the outer ring. The rolling elements are disposed between the outer ring and the inner shaft. The outer ring includes an outer cylinder (40), an inner cylinder (42), and a joint member (44). The outer cylinder is made of light alloy. The inner cylinder is made of steel. The inner cylinder is press-fitted into the outer cylinder. The inner cylinder has rolling surfaces (121, 122) with which the rolling elements contact.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hub unit, and more particularly, to a hub unit in which a part of an outer ring is formed of a light alloy.

  In recent years, weight reduction of the hub unit has been required. Therefore, for example, it has been proposed to form a part of the hub unit with an aluminum alloy. One example is disclosed in Japanese Patent Application Laid-Open No. 2012-87917.

  The hub unit described in JP 2012-87917 includes an outer member. The outer member includes two rows of outer rings and an outer frame member. The outer ring has a rolling surface. The outer frame member is made of an aluminum alloy. The outer frame member supports two rows of outer rings.

  In the above publication, the outer member is manufactured as follows. First, two rows of outer rings are placed on a mold. Subsequently, an aluminum alloy is poured into the mold. Thereafter, induction hardening is performed on the rolling surface of the outer ring.

JP 2012-87917 A

  In the above publication, the heat of induction hardening is transmitted to the outer frame member via the outer ring. Therefore, there is a possibility that the outer frame member is melted entirely or partially (particularly at the contact portion with the outer ring).

  Although it is conceivable that the rolling surface of the outer ring is induction-hardened before pouring the aluminum alloy into the mold, in this case, the outer ring may be annealed by the heat of the aluminum alloy poured into the mold. is there. When the outer ring is annealed, the life of the outer ring is reduced.

  The object of the present invention is to form a part of the hub unit with a light alloy and when the remainder is formed with steel, when the member is manufactured, the part formed with the light alloy and the steel are formed. One of the parts is less susceptible to the heat from the other.

  A hub unit according to an embodiment of the present invention includes an outer ring, an inner shaft, and a plurality of rolling elements. The inner shaft is disposed so as to be rotatable with respect to the outer ring. The plurality of rolling elements are disposed between the outer ring and the inner shaft. The outer ring includes an outer cylinder and an inner cylinder. The outer cylinder is made of a light alloy. The inner cylinder is made of steel. The inner cylinder is press-fitted into the outer cylinder. The inner cylinder has a rolling surface that contacts a plurality of rolling elements.

  In the hub unit according to the embodiment of the present invention, when manufacturing the outer ring, one of the outer cylinder and the inner cylinder is hardly affected by the heat from the other.

It is sectional drawing of the hub unit by the 1st Embodiment of this invention. It is sectional drawing which shows the outer ring | wheel with which the hub unit shown in FIG. 1 is provided. It is sectional drawing which shows the manufacturing process of the outer ring | wheel shown in FIG. 2, Comprising: It is sectional drawing which shows the state by which the inner cylinder was press-fit in the outer cylinder. FIG. 3 is a cross-sectional view showing a manufacturing process of the outer ring shown in FIG. It is sectional drawing which shows the outer ring | wheel with which the hub unit by the 2nd Embodiment of this invention is provided. It is sectional drawing which shows the application example of the outer ring | wheel shown in FIG. It is sectional drawing which shows the application example of the outer ring | wheel shown in FIG.

  A hub unit according to an embodiment of the present invention includes an outer ring, an inner shaft, and a plurality of rolling elements. The inner shaft is disposed so as to be rotatable with respect to the outer ring. The plurality of rolling elements are disposed between the outer ring and the inner shaft. The outer ring includes an outer cylinder and an inner cylinder. The outer cylinder is made of a light alloy. The inner cylinder is made of steel. The inner cylinder is press-fitted into the outer cylinder. The inner cylinder has a rolling surface that contacts a plurality of rolling elements.

  In the hub unit, press-fitting is adopted as a method of arranging the inner cylinder inside the outer cylinder. Therefore, when manufacturing the outer ring, one of the outer cylinder and the inner cylinder is hardly affected by the heat from the other. The reason is as follows.

  For example, it is assumed that the outer cylinder is formed by pouring molten light alloy into a mold in which the inner cylinder is arranged. In this case, before the inner cylinder is placed in the mold, if the induction rolling is performed on the rolling surface of the inner cylinder, the rolling surface of the inner cylinder may be annealed by the heat of the molten light alloy. There is. On the other hand, in the hub unit, since the inner cylinder is press-fitted into the outer cylinder, it is possible to suppress the rolling surface of the inner cylinder from being annealed by heat when the outer cylinder is formed.

  Further, in the above case, when the outer cylinder is formed and then induction hardening is performed on the rolling surface of the inner cylinder, the outer cylinder is wholly or partially (particularly in contact with the inner cylinder) by the heat of induction hardening. There is a risk of melting. On the other hand, in the hub unit, the entire outer cylinder is melted by the heat of induction hardening by subjecting the rolling surface of the inner cylinder to induction hardening before press-fitting the inner cylinder into the outer cylinder. Can be avoided.

  Preferably, the outer ring further includes a joining member. The joining member is joined to one axial end face of the outer cylinder and one axial end face of the inner cylinder. In this case, one of the outer cylinder and the inner cylinder can be prevented from rotating with respect to the other.

  Preferably, the joining member is joined to one end face in the axial direction of the outer cylinder and the inner cylinder by friction welding. In this case, the joining of the joining member to the outer cylinder and the inner cylinder becomes easy.

  Preferably, one of the outer cylinder and the inner cylinder includes a stopper. The stopper is formed at the other axial end of one cylinder. The stopper is in contact with the other end surface in the axial direction of the other cylinder of the outer cylinder and the inner cylinder.

  In this case, the position in the axial direction of the other cylinder with respect to the one cylinder can be defined by the stopper.

  In the case where the stopper is included, the other cylinder of the outer cylinder and the inner cylinder preferably includes a protrusion. The protrusion protrudes from the other end surface in the axial direction. A concave portion is formed in the stopper. A protrusion is fitted into the recess.

  In this case, when a radial load is applied to the outer ring, the protrusion is hooked on the inner surface of the recess, so that the deviation in the radial direction of the other cylinder relative to the one cylinder can be suppressed.

  In the case where the stopper is included, the outer cylinder preferably includes a stopper. In this case, compared with a case where the inner cylinder includes a stopper, a portion where the outer cylinder and the inner cylinder are overlapped is not exposed on the outer surface of the hub unit. Therefore, it is possible to prevent water from entering between the outer cylinder and the inner cylinder.

  The manufacturing method of the outer ring with which the hub unit is provided includes a step of induction hardening the rolling surface of the inner cylinder and a step of press-fitting the inner cylinder after induction hardening to the outer cylinder.

  According to the above manufacturing method, when the inner cylinder is press-fitted into the outer cylinder, induction hardening is performed on the rolling surface of the inner cylinder. Therefore, annealing of the rolling surface of the inner cylinder can be suppressed while avoiding melting of the entire outer cylinder.

  The manufacturing method preferably includes a step of joining a joining member to one axial end surface of the outer cylinder and one axial end face of the inner cylinder. In this case, it can suppress that one of an outer side cylinder and an inner side cylinder rotates with respect to the other.

  In the step of joining the joining members, the joining member is preferably joined to one axial end surface of the outer cylinder and one axial end face of the inner cylinder by friction welding. In this case, the process of joining the joining member to the outer cylinder and the inner cylinder becomes easy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[First Embodiment]
FIG. 1 shows a hub unit 10 according to a first embodiment of the present invention. In the following description, the axial direction is a direction in which the central axis CL of the hub unit 10 extends. The radial direction is a direction perpendicular to the central axis CL, that is, a direction perpendicular to the axial direction. The circumferential direction is a direction around the central axis CL. In a state where the hub unit 10 is arranged in the vehicle, one end side in the axial direction of the hub unit 10 (left end side in FIG. 1) corresponds to the outside of the vehicle, and the other end side in the axial direction of the hub unit 10 (in FIG. 1). The right end side) corresponds to the inside of the vehicle.

1. Overall Configuration of Hub Unit Referring to FIG. 1, the hub unit 10 includes an outer ring 12, an inner shaft 14, an inner ring 16, a plurality of rolling elements 18, a plurality of rolling elements 20, a cage 22, and a holding unit. A container 24, a seal member 26, and a seal member 28. Hereinafter, these members will be described.

  The outer ring 12 has a cylindrical shape. Two rolling surfaces 121 and 122 are formed on the inner peripheral surface of the outer ring 12. The outer ring 12 is fixed to a suspension device, for example. Details of the outer ring 12 will be described later.

  The inner shaft 14 is made of steel. Specifically, it is made of, for example, high carbon chromium bearing steel, case-hardened steel, or carbon steel for machine structure. Case-hardened steel is, for example, chromium steel.

  The inner shaft 14 is disposed inside the outer ring 12 and is positioned coaxially with the outer ring 12. The inner shaft 14 is disposed so as to be rotatable in the circumferential direction with respect to the outer ring 12.

  The inner shaft 14 has a rolling surface 141. The rolling surface 141 is formed on the outer peripheral surface of the inner shaft 14.

  The inner shaft 14 further has a flange 142. The flange 142 is formed continuously in the circumferential direction.

  The flange 142 includes a plurality of holes 14A. The plurality of holes 14A are formed, for example, at equal intervals in the circumferential direction. A wheel (specifically, a wheel), a brake disk, or the like is attached to the inner shaft 14 by a bolt 30 inserted into each of the plurality of holes 14A.

  The inner ring 16 is fixed to the inner shaft 14. Specifically, in a state where the inner shaft 14 is press-fitted into the inner ring 16, the bolt is fixed using a bolt attached to a bolt hole 14 </ b> B formed in the inner shaft 14.

  The inner ring 16 includes a rolling surface 161. The rolling surface 161 is formed on the outer peripheral surface of the inner ring 16.

  The plurality of rolling elements 18 are disposed between the outer ring 12 and the inner shaft 14. The plurality of rolling elements 18 are arranged at equal intervals in the circumferential direction by the cage 22. Each of the plurality of rolling elements 18 contacts the rolling surface 121 and the rolling surface 141.

  The plurality of rolling elements 20 are disposed between the outer ring 12 and the inner ring 16. The plurality of rolling elements 20 are arranged at equal intervals in the circumferential direction by the cage 24. Each of the plurality of rolling elements 20 contacts the rolling surface 122 and the rolling surface 161.

  The seal member 26 is disposed between the inner shaft 14 and the outer ring 12. The seal member 28 is disposed between the inner ring 16 and the outer ring 12.

2. Configuration of Outer Ring Next, details of the outer ring 12 will be described with reference to FIG. The outer ring 12 includes a cylinder 40, a cylinder 42, and a joining member 44.

  The cylinder 40 is made of a material whose mass per unit volume is smaller than the material (steel) of the inner shaft 14. In other words, the cylinder 40 is made of a material having a specific gravity smaller than that of the material of the inner shaft 14. An example of such a material is a light alloy. The light alloy may be, for example, an aluminum alloy or a magnesium alloy.

  The cylinder 40 has a stopper 40A. The stopper 40A is formed at the end of the tube 40 in the axial direction (the right end in FIG. 2). The stopper 40A protrudes from the inner peripheral surface of the tube 40. The stopper 40A is formed continuously in the circumferential direction. That is, the stopper 40A is formed in an annular shape.

  The stopper 40 </ b> A has a stopper surface 401. The stopper surface 401 has a predetermined width in the radial direction and extends continuously in the circumferential direction. That is, the stopper surface 401 is an annular surface. The stopper surface 401 defines the end of the stopper 40A in the axial direction (left end in FIG. 2).

  The cylinder 40 has a flange 40B. The flange 40 </ b> B is formed on the outer peripheral surface of the cylinder 40. The flange 40B is formed continuously in the circumferential direction, for example.

  A hole 40C is formed in the flange 40B. The cylinder 40 (outer ring 12) is fixed to the suspension device by a bolt inserted into the hole 40C.

  The cylinder 42 is made of steel. Specifically, for example, high carbon chromium bearing steel, case-hardened steel, and carbon steel for machine structure. Case-hardened steel is, for example, chromium steel.

  The cylinder 42 has a rolling surface 121 and a rolling surface 122. The rolling surface 121 and the rolling surface 122 are formed on the inner peripheral surface of the cylinder 42. The rolling surface 121 and the rolling surface 122 are separated in the axial direction. A hard layer is formed on the rolling surface 121 and the rolling surface 122 by induction hardening.

  The cylinder 42 is press-fitted into the cylinder 40. That is, the outer peripheral surface 421 of the cylinder 42 is in close contact with the inner peripheral surface 402 of the cylinder 40.

  In a state where the tube 42 is press-fitted into the tube 40, the end surface 422 in the axial direction of the tube 42 (the right end surface in FIG. 2) is in contact with the stopper surface 401. With the end surface 422 in contact with the stopper surface 401, the axial end surface 403 of the tube 40 (left end surface in FIG. 2) and the axial end surface 423 of the tube 42 (left end surface in FIG. 2) Are in the same position in the axial direction.

  The joining member 44 is an annular member. The joining member 44 overlaps the end surface 403 of the tube 40 and the end surface 423 of the tube 42 in the axial direction. The joining member 44 is joined to the cylinder 40 and the cylinder 42 by friction welding. The joining member 44 is formed of the same material as the cylinder 40, for example.

  The outer peripheral edge of the joining member 44 is at the same position as the outer peripheral surface of the tube 40 in the radial direction. The inner peripheral edge of the joining member 44 is at the same position as the inner peripheral surface of the cylinder 42 in the radial direction.

3. Method for Manufacturing Outer Ring A method for manufacturing the outer ring 12 will be described with reference to FIGS. 3A and 3B. The manufacturing method of the outer ring 12 includes a step of preparing the tube 40 and the tube 42, a step of press-fitting the tube 42 into the tube 40, and a step of friction-welding the joining member 44 to the tube 40 and the tube 42. Hereinafter, these steps will be described.

  First, the cylinder 40 and the cylinder 42 are prepared. The cylinder 40 is manufactured by casting, for example. The cylinder 42 is manufactured by forging, for example. The rolling surface 121 and the rolling surface 122 of the cylinder 42 are induction hardened. Thereby, a hard layer is formed on the rolling surface 121 and the rolling surface 122.

  Subsequently, as shown in FIG. 3A, the cylinder 42 is press-fitted into the cylinder 40. The cylinder 42 is press-fitted into the cylinder 40 from the side where the stopper 40A is not formed. The cylinder 42 is press-fitted into the cylinder 40 until the end surface 422 of the cylinder 42 contacts the stopper surface 401 of the cylinder 40.

  Subsequently, as shown in FIG. 3B, the joining member 44 is friction-welded to the cylinder 40 and the cylinder 42. Specifically, it is as follows.

  First, the cylinder 40 and the cylinder 42 are rotated. Subsequently, the joining member 44 is pressed against the cylinder 40 and the cylinder 42. The joining member 44 is softened by the frictional heat at this time. When the joining member 44 is softened, the tube 40 and the tube 42 may be softened at a portion in contact with the joining member 44. When the joining member 44 is softened, the rotation of the tube 40 and the tube 42 is stopped. This state is maintained, and it waits for the softened joining member 44 to cool and harden. As a result, the joining member 44 is joined to the cylinder 40 and the cylinder 42 by friction welding.

  In the hub unit 10 described above, a part of the outer ring 12 (specifically, the cylinder 40) is made of a light alloy. Therefore, the hub unit 10 can be reduced in weight.

  In the outer ring 12, the cylinder 42 is press-fitted into the cylinder 40. That is, the cylinder 40 and the cylinder 42 are manufactured separately. Therefore, for example, compared with the case where the molten light alloy is poured into a mold in which the cylinder 42 is disposed, the cylinder 42 is less susceptible to heat. As a result, for example, as compared with the case where the rolling surface 121 and the cylinder 42 having a hard layer formed on the rolling surface 122 are arranged in the mold and the molten light alloy is poured into the mold, the rolling surface 121 and It can suppress that the hard layer formed in the rolling surface 122 is annealed.

  In the outer ring 12, induction hardening is performed on the rolling surface 121 and the rolling surface 122 of the cylinder 42 at the stage of press-fitting into the cylinder 40. Therefore, it can be avoided that the heat of induction hardening is transmitted to the tube 40 and the entire tube 40 is melted.

  In the outer ring 12, the joining member 44 is joined to one end of the cylinder 42 and the cylinder 40 in the axial direction. Therefore, it can suppress that one of the pipe | tube 42 and the pipe | tube 40 rotates with respect to the other.

  In the outer ring 12, the joining member 44 is joined to only one axial end (left end in FIG. 2) of the cylinder 42 and the cylinder 40. Therefore, compared with the case where a joining member is joined to the axial direction both ends of the cylinder 42 and the cylinder 40, the number of processes when manufacturing the outer ring can be reduced.

  In the outer ring 12, heat due to friction welding when the joining member 44 is joined to the axial ends of the cylinder 42 and the cylinder 40 mainly acts on the axial ends of the cylinder 40 and the cylinder 42. Therefore, the entire tube 40 and the tube 42 are not easily affected by heat due to friction welding. As a result, the hard layer formed on the rolling surface 121 and the rolling surface 122 is annealed while preventing the tube 40 from being entirely or partially softened (for example, at a portion in contact with the tube 42). Can be suppressed.

  In the outer ring 12, the cylinder 42 is press-fitted into the cylinder 40 until the end surface 422 contacts the stopper surface 401. That is, the press-fitting amount of the cylinder 42 with respect to the cylinder 40 is set in advance. Therefore, positioning of the cylinder 42 with respect to the cylinder 40 in the axial direction is easy.

  In the outer ring 12, a stopper 40 </ b> A is formed on the cylinder 40. Therefore, compared with the case where the stopper is formed on the tube 42, the overlapping portion of the tube 40 and the tube 42 is not exposed on the outer surface of the hub unit. As a result, it is possible to prevent water from entering between the tube 40 and the tube 42.

[Second Embodiment]
With reference to FIG. 4, the outer ring 12A employed in the second embodiment of the present invention will be described. Compared to the outer ring 12, the outer ring 12 </ b> A has a protrusion 42 </ b> A formed on the end surface 422 of the cylinder 42, and a recess 40 </ b> D formed on the stopper 40 </ b> A of the cylinder 40. Hereinafter, the details of the protrusion 42A and the recess 40D will be described.

  The protrusion 42 </ b> A protrudes from the end surface 422 of the cylinder 42. The protrusion 42A extends continuously in the circumferential direction. That is, the protrusion 42A is formed in an annular shape. The protrusion 42A extends in the axial direction with a substantially constant inner diameter and outer diameter.

  The recess 40D is formed on the stopper surface 401 of the stopper 40A. The recess 40D has a groove shape, opens in the stopper surface 401, and extends continuously in the circumferential direction. That is, the recess 40D is formed in an annular shape. The recess 40D extends in the axial direction with a substantially constant inner diameter and outer diameter.

  A protrusion 42A is located in the recess 40D. At this time, the inner peripheral surface of the protrusion 42A is in contact with the inner peripheral surface of the recess 40D. The outer peripheral surface of the protrusion 42A is in contact with the outer peripheral surface of the recess 40D.

  Even in the hub unit having such an outer ring 12A, the same effects as those of the first embodiment can be obtained.

  In the present embodiment, the protrusion 42A is located in the recess 40D. Therefore, when a radial force acts on the outer ring A, the inner peripheral surface of the protrusion 42A is caught on the inner peripheral surface of the recess 40D. As a result, the displacement in the radial direction of the cylinder 42 with respect to the cylinder 40 can be suppressed.

[Application Example 1]
The outer ring 12B as an application example of the outer ring 12 will be described with reference to FIG. In the outer ring 12, the joining member 44 is friction-welded to one end in the axial direction of the cylinder 40 and the cylinder 42 (the left end in FIG. 2), but in the outer ring 12B, the other axial end of the cylinder 40 and the cylinder 42 (in FIG. 2). The joining member 44 is joined to the right end) by friction welding. Hereinafter, the details of the outer ring 12 </ b> B will be described in comparison with the outer ring 12.

  In the outer ring 12 </ b> B, the cylinder 40 does not have the end surface 403 compared to the outer ring 12. Instead, the cylinder 40 has a stopper 40E.

  The stopper 40E is formed at the end of the tube 40 in the axial direction (left end portion in FIG. 4). The stopper 40E protrudes from the inner peripheral surface of the cylinder 40. The stopper 40E is formed continuously in the circumferential direction. That is, the stopper 40E is formed in an annular shape.

  The stopper 40E has a stopper surface 404. The stopper surface 404 has a predetermined width in the radial direction and extends continuously in the circumferential direction. That is, the stopper surface 404 is an annular surface. The stopper surface 404 defines the end of the stopper 40E in the axial direction (the right end in FIG. 4).

  Compared to the outer ring 12, the outer ring 12 </ b> B does not have the stopper 40 </ b> A in the cylinder 40. Instead, the tube 40 has an end surface 405.

  In the outer ring 12 </ b> B, the end surface 423 of the cylinder 42 is in contact with the stopper surface 404 while the cylinder 42 is press-fitted into the cylinder 40. In the outer ring 12 </ b> B, the joining member 44 is joined to the end surface 422 of the tube 42 and the end surface 405 of the tube 40 by friction welding.

  Even in the hub unit having such an outer ring 12B, the same effects as those of the first embodiment can be obtained.

[Application 2]
The outer ring 12C as an application example of the outer ring 12B will be described with reference to FIG. The outer ring 12 </ b> C has a protrusion 42 </ b> B formed on the end surface 423 of the cylinder 42 and a recess 40 </ b> F formed on the stopper 40 </ b> D of the cylinder 40 compared to the outer ring 12 </ b> B. Hereinafter, the details of the protrusion 42B and the recess 40F will be described.

  The protrusion 42 </ b> B protrudes from the end surface 423 of the cylinder 42. The protrusion 42B extends continuously in the circumferential direction. That is, the protrusion 42B is formed in an annular shape. The protrusion 42B extends in the axial direction with a substantially constant inner diameter and outer diameter.

  The recess 40F is formed on the stopper surface 404 of the stopper 40E. The recess 40F has a groove shape, opens in the stopper surface 404, and extends continuously in the circumferential direction. That is, the recess 40F is formed in an annular shape. The recess 40F extends in the axial direction with a substantially constant inner diameter and outer diameter.

  A protrusion 42B is located in the recess 40F. At this time, the inner peripheral surface of the protrusion 42B is in contact with the inner peripheral surface of the recess 40F. The outer peripheral surface of the protrusion 42B is in contact with the outer peripheral surface of the recess 40F.

  Even in the hub unit having such an outer ring 12C, the same effects as those of the first embodiment can be obtained.

  In this application example, the protrusion 42B is located in the recess 40F. Therefore, when a radial force is applied to the outer ring 12C, the inner peripheral surface of the protrusion 42B is caught on the inner peripheral surface of the recess 40F. As a result, the displacement in the radial direction of the cylinder 42 with respect to the cylinder 40 can be suppressed.

  As mentioned above, although embodiment of this invention was explained in full detail, these are illustrations to the last, Comprising: This invention is not limited at all by the above-mentioned embodiment.

  For example, the end surfaces 403 and 423 of the cylinder 40 and the cylinder 42 may not be at the same position in the axial direction. In this case, the surface of the joining member 44 that overlaps the end surfaces 403 and 423 of the tube 40 and the tube 42 may be a step surface.

  For example, in the above embodiment, the stoppers 40A and 40E may not be provided. In this case, preferably, a joining member is joined to both ends of the cylinder 40 and the cylinder 42 in the axial direction.

10: Hub unit, 12: Outer ring, 121: Rolling surface, 122: Rolling surface, 14: Inner shaft, 18: Rolling member, 20: Rolling member, 40: Tube (outer tube), 40A: Stopper, 403: End surface, 40D: concave portion, 42: tube (inner tube), 423: end surface, 44: joining member (member)

Claims (8)

Outer ring,
An inner shaft arranged rotatably with respect to the outer ring;
A plurality of rolling elements disposed between the outer ring and the inner shaft;
The outer ring is
A light alloy outer tube,
A steel inner cylinder press-fitted into the outer cylinder and having a rolling surface with which the plurality of rolling elements contact;
A hub unit including a member joined to one end face in the axial direction of the outer cylinder and the inner cylinder. The hub unit according to claim 1,
The hub unit, wherein the member is joined to one axial end surface of the outer cylinder and the inner cylinder by friction welding. The hub unit according to claim 1 or 2,
One of the outer cylinder and the inner cylinder is
A hub unit including a stopper formed at the other axial end and in contact with the other axial end surface of the other cylinder. The hub unit according to claim 3,
The other cylinder includes a protrusion protruding from the other end surface in the axial direction,
A hub unit in which the stopper is formed with a recess into which the protrusion is fitted. The hub unit according to claim 3 or 4,
A hub unit, wherein the outer cylinder includes the stopper. A method of manufacturing an outer ring used in a hub unit,
A process of induction hardening the rolling surface of the light alloy inner cylinder;
And a step of press-fitting the inner cylinder after the induction hardening with respect to the steel outer cylinder. The outer ring manufacturing method according to claim 6, further comprising:
The manufacturing method of an outer ring | wheel including the process of joining a member to the axial direction one end surface which the said outer side cylinder and the said inner side cylinder have. It is a manufacturing method of the outer ring according to claim 7,
In the step of joining the members, the outer ring and the inner tube are joined to one end surface in the axial direction of the outer cylinder and the inner cylinder by friction welding.

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