Patent Description:
A hub unit bearing is known as an example of a staking assembly in which a first member and a second member are combined in the axial direction. Vehicle wheels and braking rotating bodies are rotatably supported to suspension devices by the hub unit bearings. <FIG> shows an example of a conventional hub unit bearing. A hub unit bearing <NUM> rotatably supports a hub <NUM> on the inner radial side of an outer race <NUM> through a plurality of rolling elements 103a and 103b.

Regarding the hub unit bearing <NUM>, the outside in the axial direction is the left side of <FIG> which is the outside in the width direction of the vehicle body while the hub unit bearing <NUM> is assembled to the automobile. The inside in the axial direction is the right side of <FIG> which is the center side in the width direction of the vehicle body while the hub unit bearing <NUM> is assembled to the automobile. In the example of <FIG>, regarding the hub unit bearing <NUM>, the inside in the axial direction corresponds to one side in the axial direction and the outside in the axial direction corresponds to the other side in the axial direction.

The outer race <NUM> includes double-row outer race tracks 104a and 104b provided on an inner peripheral surface and includes a stationary flange <NUM> which is provided in an axially intermediate portion to support and fix the outer race <NUM> to a knuckle of a suspension device. The hub <NUM> includes double-row inner race tracks 106a and 106b provided on an outer peripheral surface and includes a rotary flange <NUM> provided in an axially outer portion to support and fix the vehicle wheel and the braking rotating body by the hub <NUM>. The plurality of rolling elements 103a and 103b are arranged for each row between the double-row outer race tracks 104a and 104b and the double-row inner race tracks 106a and 106b. With such a configuration, the hub <NUM> is rotatably supported on the inner radial side of the outer race <NUM>.

In the example of <FIG>, the hub <NUM> has a combination of a hub main body (hub race) <NUM> corresponding to a first hub element (first member) and an internal inner race <NUM> corresponding to a second hub element (second member). The inner race track 106a on the inside in the axial direction in the double-row inner race tracks 106a and 106b is provided on the outer peripheral surface of the internal inner race <NUM>. The inner race track 106b on the outside in the axial direction in the double-row inner race tracks 106a and 106b is provided on the outer peripheral surface of the axially intermediate portion of the hub main body <NUM>. The rotary flange <NUM> is provided in the axially outer portion of the hub main body <NUM>. The hub main body <NUM> includes a fitting surface portion <NUM> provided on the outer peripheral surface of the axially inner portion and includes a step surface <NUM> provided at the axially outer end portion of the fitting surface portion <NUM> to be directed axially inward. The internal inner race <NUM> is externally fitted to the fitting surface portion <NUM> while the axially outer end surface abuts against the step surface <NUM>. In this state, a staking portion <NUM> is formed by plastically deforming a cylindrical portion <NUM>, protruding axially inward from a portion to which the internal inner race <NUM> is externally fitted in the hub main body <NUM>, axially outward. The axially inner end surface of the internal inner race <NUM> is suppressed by the staking portion <NUM>. In this way, the axially inner end surface of the internal inner race <NUM> is suppressed by the staking portion <NUM> so that a preload is applied to the rolling elements 103a and 103b. Then, the rigidity required for the hub unit bearing <NUM> is ensured by the preload.

As a device for forming the staking portion <NUM> used when manufacturing the hub unit bearing <NUM>, a staking device <NUM> including a pressing die (staking die) <NUM> shown in <FIG> is known (for example, see <CIT> (Patent Literature <NUM>)). The pressing die <NUM> is supported to be rotatable about a rotation axis β inclined by an angle θ with respect to a reference axis α. The lower end portion of the pressing die <NUM> is provided with a processing surface portion <NUM>. The processing surface portion <NUM> is formed by an inner surface of an annular concave portion centered on the rotation axis β.

When forming the staking portion <NUM>, the pressing die <NUM> is rotationally driven about the reference axis α without rotating the hub main body <NUM> about the reference axis α while pressing a part of the processing surface portion <NUM> in the circumferential direction in the pressing die <NUM> against a part of the cylindrical portion <NUM> of the hub main body <NUM> in the circumferential direction in a state in which the center axis of the hub main body <NUM> is aligned to the reference axis α. Then, the pressing die <NUM> is rotated about the rotation axis β based on a frictional force acting on the contact portion between the processing surface portion <NUM> and the cylindrical portion <NUM> in accordance with this operation. Accordingly, an application position of a processing force directed downward in the up and down direction (axially outward) and radially outward is continuously changed in the circumferential direction of the cylindrical portion <NUM> while applying the processing force from a part of the processing surface portion <NUM> of the pressing die <NUM> in the circumferential direction to a part of the cylindrical portion <NUM> in the circumferential direction. Accordingly, the staking portion <NUM> is formed by plastically deforming the cylindrical portion <NUM> to be expanded radially outward while axially crushing the cylindrical portion.

<CIT> (Patent literature <NUM>, forming the closest prior art) discloses a method of manufacturing a hub bearing unit, wherein the step of forming the stacking portion comprises a first step of applying load at a first angle, an intermediate step of changing the angle and a second step of applying load at a second angle.

In the conventional method of manufacturing the hub unit bearing <NUM>, there is room for improvement in terms of improving the quality of the hub unit bearing <NUM>. This point will be described below. That is, in the method of manufacturing the conventional hub unit bearing <NUM>, the processing force directed downward in the up and down direction and radially outward is applied from the processing surface portion <NUM> of the pressing die <NUM> to the cylindrical portion <NUM> from the start to the end of processing for forming the staking portion <NUM>. Therefore, at the final stage of processing for forming the staking portion <NUM>, the thick portion of the axially inner end portion of the hub main body <NUM> flows radially outward along the axially inner surface of the internal inner race <NUM> as indicated by an arrow Xo in <FIG>. Then, when such a thick portion flows, a force is applied to the axially inner surface of the internal inner race <NUM> in the diameter expansion direction and the internal inner race <NUM> expands in the diameter expansion direction.

In the manufacturing of the hub unit bearing <NUM>, it is desired to prevent or suppress (control the outer shape) the expansion of the internal inner race <NUM> in the diameter expansion direction in accordance with the above-described processing of the staking portion <NUM>. The outer shape control of the inner race <NUM> is advantageous for preventing the breakage of the internal inner race <NUM>, suppressing a variation in preload, or decreasing the rotational friction of the hub <NUM> with respect to the outer race <NUM> due to the formation of the staking portion <NUM>. Additionally, the same also applies to the other staking assembly in which the first member and the second member are combined in the axial direction.

An object of the present invention is to provide a method of manufacturing a hub bearing unit according to claim <NUM> and a method of manufacturing a vehicle according to claim <NUM>, which are advantageous for improving quality.

In an aspect of the present invention, a method of manufacturing a hub bearing unit is defined in claim <NUM>.

Advantageously, a hub unit bearing to be manufactured includes an outer race having double-row outer race tracks provided on an inner peripheral surface, a hub having double-row inner race tracks provided on an outer peripheral surface, and a plurality of rolling elements arranged for each row between the double-row inner race tracks and the double-row outer race tracks.

The hub includes a first hub element and a second hub element in which an inner race track on one side in the axial direction in the double-row inner race tracks is provided on an outer peripheral surface.

The second hub element is externally fitted to the first hub element and suppresses a side surface on one side in the axial direction by a staking portion provided at one axial end portion of the first hub element.

As a configuration of the hub unit bearing to be manufactured in the present invention, it is possible to obtain a configuration in which the inner race track on the outside in the axial direction in the double-row inner race tracks is provided on the outer peripheral surface of the first hub element or a configuration in which the inner race track on the outside in the axial direction in the double-row inner race tracks is provided on the outer peripheral surface of the other hub element externally fitted to the first hub element.

In the manufacturing method, the staking portion forming step includes the first and second steps below.

The first step is a step of forming a staking portion intermediary body by plastically deforming a cylindrical portion provided at one axial end portion of the first hub element before forming the staking portion to be expanded radially outward while axially crushing the cylindrical portion in such a manner that an application position of a processing force directed toward the other side in the axial direction and directed radially outward is continuously changed in the circumferential direction of the cylindrical portion while applying the processing force to a part of the cylindrical portion in the circumferential direction.

The second step is a step of forming the staking portion by plastically deforming the staking portion intermediary body to be pressed radially inward while axially crushing the staking portion intermediary body in such a manner that an application position of a processing force directed toward the other side in the axial direction and directed inward in the radial direction is continuously changed in the circumferential direction of the staking portion intermediary body while applying the processing force to a part of the staking portion intermediary body in the circumferential direction.

In the manufacturing method, the first hub element and a pressing die are relatively rotated about a center axis of the first hub element while pressing a part of a processing surface portion in the circumferential direction in the pressing die including a rotation axis inclined with respect to the center axis of the first hub element and the processing surface portion formed by an inner surface of an annular concave portion centered on the rotation axis against a part of a processing object which is the cylindrical portion or the staking portion intermediary body in the circumferential direction in order to continuously change the application position of the processing force in the circumferential direction of the processing object while applying the processing force to the processing object.

For example, as a more specific aspect in this case, the following first to third aspects can be adopted.

In the first aspect, the pressing die is rotated about the rotation axis based on a frictional force acting on the contact portion between the processing surface portion and the processing object by rotationally driving the first hub element about the center axis of the first hub element without rotating the pressing die about the center axis of the first hub element while pressing a part of the processing surface portion in the circumferential direction in the pressing die against a part of the processing object in the circumferential direction.

In the second aspect, the first hub element is rotated about the center axis of the first hub element based on a frictional force acting on the contact portion between the processing surface portion and the processing object by rotationally driving the pressing die about the rotation axis without rotating the pressing die about the center axis of the first hub element while pressing a part of the processing surface portion in the circumferential direction in the pressing die against a part of the processing object in the circumferential direction.

In the third aspect, the pressing die is rotated about the rotation axis based on a frictional force acting on the contact portion between the processing surface portion and the processing object by rotationally driving the pressing die about the center axis of the first hub element without rotating the first hub element about the center axis of the first hub element while pressing a part of the processing surface portion in the circumferential direction in the pressing die against a part of the processing object in the circumferential direction.

In an aspect of the present invention, a position of the pressing die in the axial direction of the rotation axis in the second step may be disposed to be shifted toward the first hub element in relation to the position of the pressing die in the axial direction of the rotation axis in the first step.

In an aspect of the present invention, an inclination angle of the rotation axis with respect to the center axis of the first hub element in the second step may be set to be larger than an inclination angle of the rotation axis for the center axis of the first hub element in the first step.

In an aspect of the present invention, a time point of ending the first step may be determined by using a value of a torque for relatively rotating the first hub element and the pressing die about the center axis of the first hub element.

In an aspect of the present invention, the first step and the second step may be performed by using one staking device.

In an aspect of the present invention, a staking device includes: a reference axis; a pressing die which includes a rotation axis inclined with respect to the reference axis and a processing surface portion formed by an inner surface of an annular concave portion centered on the rotation axis; and a mechanism which displaces the pressing die in the axial direction of the rotation axis.

In an aspect of the present invention, the staking device includes: a reference axis; a pressing die which includes a rotation axis inclined with respect to the reference axis and a processing surface portion formed by an inner surface of an annular concave portion centered on the rotation axis; and a mechanism which changes an inclination angle of the rotation axis with respect to the reference axis.

In an aspect of the present invention, the staking device may further include a mechanism which rotationally drives the first hub element about the reference axis while a center axis of the first hub element is aligned to the reference axis.

In an aspect of the present invention, the staking device may further include a mechanism which rotationally drives the pressing die about the rotation axis.

In an aspect of the present invention, a staking assembly includes: a first member; and a second member having a hole into which the first member is inserted and axially combined with the first member, wherein the first member includes a staking portion for the second member formed by deforming a shaft end of the first member radially outward, and wherein the staking portion includes a radially outer portion having a deformed portion at which a load was applied.

In an aspect of the present invention, a vehicle includes the hub unit bearing.

In an aspect of the present invention, a method of manufacturing a vehicle manufactures the hub unit bearing by the method of manufacturing the hub unit bearing.

An embodiment of the present invention will be described with reference to <FIG>.

<FIG> shows a hub unit bearing <NUM> to be manufactured. The hub unit bearing (staking assembly, staking unit) <NUM> is for a driven wheel and includes an outer race <NUM>, a hub <NUM>, and a plurality of rolling elements 4a and 4b.

Regarding the hub unit bearing <NUM>, the outside in the axial direction is the left side of <FIG> which is the outside in the width direction of the vehicle while the hub unit bearing is assembled to the vehicle. The inside in the axial direction is the right side of <FIG> which is the center side in the width direction of the vehicle while the hub unit bearing is assembled to the vehicle. In this example, regarding the hub unit bearing <NUM>, the inside in the axial direction corresponds to one side in the axial direction and the outside in the axial direction corresponds to the other side in the axial direction.

The outer race <NUM> includes double-row outer race tracks 5a and 5b and a stationary flange <NUM>. In an example, the outer races 5a and 5b are made of a hard metal such as medium carbon steel. In another example, the outer races 5a and 5b can be made of different materials. The double-row outer race tracks 5a and 5b are provided on the inner peripheral surface of the axially intermediate portion of the outer race <NUM> over the entire circumference. The stationary flange <NUM> protrudes radially outward from the axially intermediate portion of the outer race <NUM> and includes support holes <NUM> which are screw holes at a plurality of positions in the circumferential direction.

The outer race <NUM> is supported and fixed to a knuckle <NUM> in such a manner that a bolt <NUM> inserted through a passage hole <NUM> of the knuckle <NUM> constituting the suspension device of the vehicle is screwed and tightened into a support hole <NUM> of the stationary flange <NUM> from the inside in the axial direction.

The hub (staking assembly, staking unit) <NUM> is disposed on the radially inner side of the outer race <NUM> coaxially with the outer race <NUM>. The hub <NUM> includes double-row inner race tracks 11a and 11b and a rotary flange <NUM>. The double-row inner race tracks 11a and 11b are provided at portions facing the double-row outer race tracks 5a and 5b in the outer peripheral surface (outer surface) of the hub <NUM> over the entire circumference. The rotary flange <NUM> protrudes radially outward from a portion located on the axially outer side in relation to the outer race <NUM> in the hub <NUM> and includes attachment holes <NUM> provided at a plurality of positions in the circumferential direction.

In an example, a serration portion provided near a base end of a stud <NUM> is press-inserted into the attachment hole <NUM> in order to connect and fix a braking rotating body <NUM> such as a disc or a drum to the rotary flange <NUM>. Further, the intermediate portion of the stud <NUM> is press-inserted into the passage hole <NUM> of the braking rotating body <NUM>. Further, in order to fix a wheel <NUM> constituting a vehicle wheel to the rotary flange <NUM>, a nut <NUM> is screwed and tightened to a male screw portion provided at the front end portion of the stud <NUM> while the male screw portion is inserted through a passage hole <NUM> of the wheel <NUM>.

A plurality of the rolling elements 4a and 4b are arranged for each row between the double-row outer race tracks 5a and 5b and the double-row inner race tracks 11a and 11b. In an example, each of the rolling elements 4a and 4b is made of a hard metal such as bearing steel or ceramics. In another example, the rolling elements 4a and 4b can be made of different materials. The rolling elements 4a and 4b are rotatably held by cages 20a and 20b for each row. In the example of <FIG>, balls are used as the rolling elements 4a and 4b, but tapered rollers (tapered hubs) are also used as shown in the example of <FIG> in some cases.

The hub (staking assembly, staking unit) <NUM> is composed of a hub main body (first member, hub race) <NUM>, an internal inner race (second member) 22a, and an external inner race 22b. In an example, the hub main body <NUM> is made of a hard metal such as medium carbon steel. Each of the internal inner race 22a and the external inner race 22b is made of a hard metal such as bearing steel. In another example, the hub main body <NUM>, the internal inner race 22a, and the external inner race 22b can be made of different materials. The hub (staking assembly) <NUM> substantially has a combination of the hub main body (first member) <NUM> and the inner races (second member) 22a and 22b in the axial direction. The hub <NUM> includes the hub main body <NUM> which includes an outer peripheral surface (outer surface) <NUM> and the inner races 22a and 22b which are arranged on the outer peripheral surface (outer surface) <NUM> of the hub main body <NUM> and are held by the hub main body <NUM>. Additionally, the hub main body <NUM> corresponds to the first hub element (first member) and the internal inner race 22a corresponds to the second hub element (second member). The inner race track 11a on the inside in the axial direction is provided on the outer peripheral surface of the internal inner race 22a. The inner race track 11b on the outside in the axial direction is provided on the outer peripheral surface of the external inner race 22b. The rotary flange <NUM> is provided in the axially outer portion of the hub main body <NUM>. The hub main body <NUM> includes a cylindrical fitting surface portion <NUM> which is provided on the outer peripheral surface of the axially intermediate portion. Further, the hub main body <NUM> includes a step surface <NUM> which is provided at the axially outer end portion of the fitting surface portion <NUM> to face the inside in the axial direction. The internal inner race 22a and the external inner race 22b are externally fitted to the fitting surface portion <NUM> of the hub main body <NUM> by tightening (press-fitting). Further, the hub main body <NUM> includes a staking portion <NUM> which is provided at the axially inner end portion. The staking portion <NUM> is bent radially outward from the axially inner end portion of the portion to which the internal inner race 22a is externally fitted in the hub main body <NUM> and suppresses the axially inner surface of the internal inner race 22a. That is, the internal inner race 22a and the external inner race 22b are connected and fixed to the hub main body <NUM> while being sandwiched between the staking portion <NUM> and the step surface <NUM> of the hub main body <NUM> in the axial direction. In this state, a preload is applied to the rolling elements 4a and 4b together with the contact angle of the back surface combination type. In an example, the hub main body <NUM> includes the staking portion <NUM> for the inner races 22a and 22b (the staking portion <NUM> for holding the inner races 22a and 22b). The hub main body <NUM> is inserted into holes <NUM> of the inner races 22a and 22b. The staking portion <NUM> which has a bend extending in the circumferential direction and covers the shaft end portion of the inner race 22a is provided in the peripheral wall of the hub main body <NUM>.

Additionally, the staking portion <NUM> is formed by plastically deforming a cylindrical portion <NUM> extending axially inward from the axially inner end portion of the portion to which the internal inner race 22a is externally fitted in the hub main body <NUM> before forming the staking portion <NUM>. In an embodiment, the hub main body <NUM> includes the staking portion <NUM> for the inner race 22a formed by deforming the shaft end of the hub main body <NUM> radially outward and the staking portion includes a radially outer portion having a deformed portion (processing mark) <NUM> (<FIG>) at which a load was applied.

Next, a staking device <NUM> which forms the staking portion <NUM> and connects and fixes the hub main body <NUM> to the internal inner race 22a and the external inner race 22b will be described with reference to <FIG>.

As shown in a schematic configuration of <FIG>, the staking device <NUM> includes a frame <NUM>, a work side device (first device) <NUM>, and a tool side device (second device) <NUM>.

The frame <NUM> includes a lower frame <NUM>, an upper frame <NUM> which is disposed above the lower frame <NUM>, and a plurality of columns <NUM> which support the upper frame <NUM> with respect to the lower frame <NUM>.

A work side device <NUM> is supported by the lower frame <NUM>. The work side device <NUM> includes a holder <NUM>, an outer race support mechanism (not shown), a pressing mechanism (not shown), and a rotational drive mechanism (not shown).

The holder <NUM> can support the hub main body <NUM> constituting the hub unit bearing <NUM> assembled as below before forming the staking portion <NUM>. Specifically, the holder <NUM> can support the axially outer portion (lower portion) of the hub <NUM> (hub main body <NUM>) while the axially inner portion of the hub unit bearing <NUM> before forming the staking portion <NUM> is directed upward and the center axis of the hub <NUM> (the center axis of the hub main body <NUM>) is aligned to the reference axis α in the up and down direction which is the own center axis.

The outer race support mechanism is a mechanism which non-rotatably supports the outer race <NUM> while the axially outer portion of the hub main body <NUM> constituting the hub unit bearing <NUM> is supported by the holder <NUM>.

The pressing mechanism is, for example, a mechanism which uses a hydraulic pump as a drive source and moves the holder <NUM> and the outer race support mechanism in the axial direction (the up and down direction) of the reference axis α. Thus, the pressing mechanism can move the hub unit bearing <NUM> supported by the holder <NUM> and the outer race support mechanism in the axial direction (the up and down direction) of the reference axis α.

The rotational drive mechanism is, for example, a mechanism which uses an electric motor as a drive source and rotationally drives the holder <NUM> about the reference axis α. Thus, the rotational drive mechanism can rotationally drive the hub <NUM> supported by the holder <NUM> about the reference axis α.

A tool side device <NUM> is supported by the upper frame <NUM>. The tool side device <NUM> includes a cylinder attached spindle <NUM> and a pressing die (molding die, staking die) <NUM>.

The cylinder attached spindle <NUM> includes a hydraulic or pneumatic cylinder device <NUM> and a spindle <NUM>. The cylinder device <NUM> rotatably supports the spindle <NUM> therein about the center axis β of the spindle <NUM>. The cylinder device <NUM> can displace the spindle <NUM> in the axial direction of the center axis β. Such a cylinder attached spindle <NUM> is supported by the upper frame <NUM> while the center axis β of the spindle <NUM> is inclined with respect to the reference axis α by an angle θ. Additionally, a point P in part (A) of <FIG>, part (A) and part (B) of <FIG>, part (A) and part (B) of <FIG>, and <FIG> to be described later is an intersection between the reference axis α and the rotation axis β.

The pressing die <NUM> is fixed to the lower end portion which is the front end portion of the spindle <NUM> directly or through other members coaxially with the spindle <NUM>. Thus, the pressing die <NUM> is supported by the cylinder device <NUM> to be rotatable about the own center axis (the center axis β of the spindle <NUM>) through the spindle <NUM>. Further, the cylinder device <NUM> can displace the pressing die <NUM> in the axial direction of the center axis β through the spindle <NUM>. Additionally, in the following description, the center axis of the pressing die <NUM> is appropriately referred to as the rotation axis β (that is, the same symbol β as the center axis of the spindle <NUM> is used as the symbol of the rotation axis). The lower end surface which is the front end surface of the pressing die <NUM> is provided with a processing surface portion <NUM> which is formed by an inner surface of an annular concave portion centered on the rotation axis β.

Next, a method of forming the staking portion <NUM> using the staking device <NUM> at the time of manufacturing the hub unit bearing <NUM> will be described. A method of manufacturing the hub unit bearing <NUM> includes a step of combining the hub main body (first hub element) <NUM> and the inner races (second hub elements) 22a and 22b in the axial direction and a staking portion forming step of forming the staking portion <NUM> for the inner race 22a in the hub main body <NUM>. The staking portion forming step includes applying a load including a first load component directed inward in the radial direction to the radially outer portion of the hub main body <NUM> as will be described later.

The work of forming the staking portion <NUM> is performed in an assembly state (first assembly state) of the hub unit bearing <NUM> before forming the staking portion <NUM>. Therefore, the hub unit bearing <NUM> before forming the staking portion <NUM> is assembled in advance.

The hub unit bearing <NUM> before forming the staking portion <NUM> can be assembled by an appropriate procedure, but can be assembled, for example, by the following procedure. First, the rolling element 4a of the inner row in the axial direction is disposed on the inner radial side of the outer race track 5a on the inside in the axial direction of the outer race <NUM> while being held by the cage 20a on the inside in the axial direction. At the same time, the rolling element 4b of the outer row in the axial direction is disposed on the inner radial side of the outer race track 5b on the outside in the axial direction of the outer race <NUM> while being held by the cage 20b on the outside in the axial direction. Next, the internal inner race 22a is inserted into the inner radial side of the outer race <NUM> from the inside in the axial direction. On the other hand, the external inner race 22b is inserted from the outside in the axial direction. Next, the internal inner race 22a and the external inner race 22b are externally fitted to the fitting surface portion <NUM> of the hub main body <NUM> before forming the staking portion <NUM> while mutually facing axial side surfaces are in contact with each other. On the other hand, the axially outer surface of the external inner race 22b is brought into contact with the step surface <NUM> of the hub main body <NUM>. Accordingly, the hub unit bearing <NUM> before forming the staking portion <NUM> is assembled. Additionally, the assembly procedure can be appropriately changed.

When forming the staking portion <NUM> using the staking device <NUM>, first, the hub unit bearing <NUM> before forming the staking portion <NUM> is set in the staking device <NUM>. Specifically, as shown in <FIG>, the axially inner portion of the hub unit bearing <NUM> before forming the staking portion <NUM> is directed upward and the center axis of the hub <NUM> (the center axis of the holder <NUM> constituting the staking device <NUM>) is aligned to the reference axis α. In a state in which the axes are aligned to each other, the axially outer portion (lower portion) of the hub main body <NUM> is supported by the holder <NUM> (see part (A) and (B) of <FIG>). Further, the outer race <NUM> is non-rotatably supported by the outer race support mechanism. Additionally, the hub unit bearing <NUM> is located below the position shown in <FIG> in the state before starting to process the staking portion <NUM> and the pressing die <NUM> does not come into contact with the cylindrical portion <NUM> of the hub main body <NUM>.

If the hub unit bearing <NUM> before forming the staking portion <NUM> is set in the staking device <NUM> as described above, the work of forming the staking portion <NUM> is subsequently started. The work of forming the staking portion <NUM> is divided into a first step and a second step.

In the first step, the hub <NUM> is rotated about the reference axis α with respect to the outer race <NUM> based on the rotational driving of the holder <NUM> using the rotational drive mechanism of the work side device <NUM>. Then, in this state, the hub unit bearing <NUM> is moved upward based on the upward moving of the holder <NUM> and the outer race support mechanism using the pressing mechanism of the work side device <NUM>. Accordingly, as shown in <FIG>, the hub <NUM> is rotated about the reference axis α with respect to the outer race <NUM> without rotating the pressing die <NUM> about the reference axis α while pressing a part in the circumferential direction of the cylindrical portion <NUM> by a part in the circumferential direction of the processing surface portion <NUM> in the pressing die <NUM>. Then, the pressing die <NUM> is rotated about the rotation axis β based on the frictional force acting on the contact portion between the processing surface portion <NUM> and the cylindrical portion <NUM> in accordance with this operation. Accordingly, in a state in which a processing force Fo which is directed downward in the up and down direction and is directed radially outward is applied to a part in the circumferential direction of the cylindrical portion <NUM> from a part in the circumferential direction of the processing surface portion <NUM> of the pressing die <NUM>, the application position of the processing force Fo is continuously changed in the circumferential direction of the cylindrical portion <NUM>. A load including a load component directed radially outward is applied to the cylindrical portion <NUM> using the pressing die <NUM> and the load application position moves in the circumferential direction. Accordingly, as shown in part (A) and part (B) of <FIG>, and <FIG>, a staking portion intermediary body <NUM> is formed by plastically deforming the cylindrical portion <NUM> to be expanded radially outward while axially crushing the cylindrical portion.

In an example, as shown in <FIG> and <FIG>, the staking portion intermediary body <NUM> is formed in a shape in which the axially outer surface of the staking portion intermediary body <NUM> slightly contacts the axially inner surface of the internal inner race 22a to a degree that the inner race track 11a on the inside in the axial direction is not deformed or the axially outer surface does not contact the axially inner surface of the internal inner race 22a. In other words, the staking portion intermediary body <NUM> is formed in a shape in which the preload of the hub unit bearing <NUM> does not change with the formation of the staking portion intermediary body <NUM>. Additionally, in this example, as shown in <FIG> and <FIG>, the processing surface portion <NUM> is in a state in which both the radially inner portion <NUM> and the radially outer portion <NUM> contact the staking portion intermediary body <NUM> at a portion in which the axially inner surfaces of the processing surface portion <NUM> and the staking portion intermediary body <NUM> contact each other. Here, the radially inner portion <NUM> of the processing surface portion <NUM> is a portion which is inclined in a direction moving away from the hub main body <NUM> (upward in <FIG> and <FIG>) with respect to the axial direction of the reference axis α as it moves outward (rightward in <FIG> and <FIG>) in the radial direction centered on the reference axis α. On the other hand, the radially outer portion <NUM> of the processing surface portion <NUM> is a portion which is inclined in a direction moving close to the hub main body <NUM> (downward in <FIG> and <FIG>) with respect to the axial direction of the reference axis α as it moves outward in the radial direction centered on the reference axis α. In this example, the upward movement of the hub unit bearing <NUM> is temporarily stopped based on the fact that the upward movement of the holder <NUM> and the outer race support mechanism by the pressing mechanism of the work side device <NUM> is temporarily stopped at the time point of forming the staking portion intermediary body <NUM>.

In an example, in order to form the staking portion intermediary body <NUM>, a time point (timing) of stopping the upward movement of the hub unit bearing <NUM> is determined based on a drive torque Ts which is a torque for rotationally driving the holder <NUM> by the rotational drive mechanism (a torque for relatively rotating the pressing die <NUM> and the hub <NUM> about the reference axis α). This point will be described with reference to <FIG>. Additionally, the drive torque Ts can be measured, for example, based on a current value of an electric motor which is a drive source of the rotational drive mechanism.

<FIG> is a diagram showing a time change of the drive torque Ts when processing the cylindrical portion <NUM> into the staking portion <NUM> without temporarily stopping the upward movement of the hub unit bearing <NUM>. In this case, the drive torque Ts gradually increases in the time zone t1 after the start of processing, settles at a substantially constant value in the subsequent time zone t2, gradually decreases in the subsequent time zone t3, and settles at a substantially constant value again in the subsequent time zone t4.

The axially inner end portion (the cylindrical portion <NUM>, the staking portion intermediary body <NUM>, the staking portion <NUM>) of the hub main body <NUM> which is processed by the processing surface portion <NUM> of the pressing die <NUM> does not contact the axially inner surface of the internal inner race 22a in the time zones t1 and t2. In the time zone t3, the axially inner end portion contacts the axially inner surface of the internal inner race 22a to a degree that the internal inner race 22a is not deformed in the diameter expansion direction (a degree that the inner race track 11a is not deformed axially inward). In the time zone t4, the internal inner race 22a is deformed in the diameter expansion direction. Additionally, the shape of the axially inner end portion of the hub main body <NUM> at this time is substantially the same (a shape curved like the staking portion <NUM> after completion) in each of the time zones t2, t3, and t4 when observing only the outer shape.

Here, in this example, the upward movement of the hub unit bearing <NUM> is temporarily stopped at the time point before entering the time zone t4 which is the time point before the deformation of the internal inner race 22a in the diameter expansion direction while confirming the drive torque Ts. Here, as the time point before entering the time zone t4, it is possible to adopt, for example, a time point immediately after shifting to the time zone t2, that is, a time point Q1 at which the drive torque Ts first begins to settle to a substantially constant value after the start of processing, or a time point immediately after shifting to the time zone t3, that is, a time point Q2 at which the drive torque Ts first begins to settle to a substantially constant value and then the drive torque Ts begins to decrease after the start of processing.

Then, in this example, the upward movement of the hub unit bearing <NUM> is temporarily stopped at a time point at which the above-described staking portion intermediary body <NUM> is formed. Then, the hub unit bearing <NUM> is slightly moved downward based on the downward movement of the holder <NUM> and the outer race support mechanism using the pressing mechanism of the work side device <NUM>. Accordingly, as shown in part (B) of <FIG> to part (A) of <FIG>, the processing surface portion <NUM> of the pressing die <NUM> and the staking portion intermediary body <NUM> are separated in the up and down direction and the first step is ended.

In the second step, in the state shown in <FIG>, the pressing die <NUM> is displaced by a predetermined amount λ (for example, λ is about <NUM> to <NUM>) toward the hub <NUM> (the direction of the arrow S1) in the axial direction of the rotation axis β based on the axial displacement of the spindle <NUM> of the cylinder device <NUM>. That is, as shown in <FIG> which is an enlarged view of a B part of <FIG>, the front end position Z of the pressing die <NUM> is slightly displaced to the left in the drawing from the reference axis α.

Then, the hub unit bearing <NUM> is moved upward again based on the upward movement of the holder <NUM> and the outer race support mechanism using the pressing mechanism of the work side device <NUM> in this state. Accordingly, the hub <NUM> is rotated about the reference axis α with respect to the outer race <NUM> without rotating the pressing die <NUM> about the reference axis α while pressing a part of the processing surface portion <NUM> in the circumferential direction in the pressing die <NUM> against a part of the staking portion intermediary body <NUM> in the circumferential direction. A load including a load component directed radially inward is applied to the radially outer portion of the staking portion intermediary body <NUM> using the pressing die <NUM> and the application position of the load moves in the circumferential direction. Then, the pressing die <NUM> is rotated about the rotation axis β based on a frictional force acting on the contact portion between the processing surface portion <NUM> and the staking portion intermediary body <NUM> in accordance with this operation. Accordingly, the staking portion <NUM> is formed by plastically deforming the staking portion intermediary body <NUM> to be pressed radially inward while axially crushing the staking portion intermediary body as shown in part (A) and part (B) of <FIG>, and <FIG>.

Here, in this example, when the staking portion <NUM> is formed as shown in part (A) and part (B) of <FIG>, and <FIG> by displacing the pressing die <NUM> by a predetermined amount in the direction of the arrow S1 as described above, in the processing surface portion <NUM>, the radially inner portion <NUM> does not contact the staking portion intermediary body <NUM> (the staking portion <NUM>) and only the radially outer portion <NUM> contacts the staking portion intermediary body <NUM> (the staking portion <NUM>) at the contact portion between the processing surface portion <NUM> and the axially inner surface of the staking portion intermediary body <NUM> (the staking portion <NUM>). Accordingly, a processing force Fi directed downward in the up and down direction and directed radially inward is applied from a part of the processing surface portion <NUM> in the circumferential direction to a part of the staking portion intermediary body <NUM> (the staking portion <NUM>) in the circumferential direction. In other words, in this example, the amount in which the pressing die <NUM> is displaced in the direction of the arrow S1 as described above is regulated so that only the radially outer portion <NUM> in the processing surface portion <NUM> contacts the staking portion intermediary body <NUM> (the staking portion <NUM>) at the contact portion between the processing surface portion <NUM> and the axially inner surface of the staking portion intermediary body <NUM> (the staking portion <NUM>) when forming the staking portion <NUM> as shown in part (A) and part (B) of <FIG>.

As described above, in this example, in the second step of the work of forming the staking portion <NUM>, the processing force (the load including a component directed radially inward) Fi directed downward in the up and down direction and directed radially inward is applied from the radially outer portion <NUM> of the processing surface portion <NUM> to the staking portion <NUM>. Therefore, in the second step, the thick portion of the staking portion <NUM> flows radially inward along the axially inner surface of the internal inner race 22a as indicated by an arrow Xi in <FIG>. Additionally, in this example, since the radially inner portion <NUM> of the processing surface portion <NUM> does not contact the staking portion <NUM> and a slight gap exists between the radially inner portion <NUM> and the staking portion <NUM> at this time, the flow of the thick portion in the direction indicated by the arrow Xi is likely to occur based on the existence of the gap. Then, in this example, a force in the diameter contraction direction is applied to the axially inner surface of the internal inner race 22a due to the flow of the thick portion. Thus, in this example, it is possible to prevent or suppress the expansion of the internal inner race 22a in the diameter expansion direction in accordance with the formation of the staking portion <NUM>. As a result, it is possible to prevent the breakage of the internal inner race 22a, suppress a variation in preload, or decrease the rotational friction of the hub <NUM> with respect to the outer race <NUM> in accordance with the formation of the staking portion <NUM>. In this way, in this example, the step of forming the staking portion <NUM> includes the first step of deforming a part of the hub main body <NUM> radially outward by applying a load including a load component directed radially outward to the hub main body <NUM> using the pressing die <NUM> and the second step of applying a load including a load component directed radially inward to a radially outer portion of a deformed portion (staking portion intermediary body (intermediate staking portion) <NUM>) of the hub main body <NUM> using the pressing die <NUM>.

Alternatively and/or additionally, it is possible to measure the torque applied from the outer race <NUM> to the outer race support mechanism of the work side device <NUM> when the staking portion <NUM> is formed. Since the value of this torque becomes a degree corresponding to the preload of the hub unit bearing <NUM> increasing in accordance with the formation of the staking portion <NUM>, it is possible to determine the time when ending the work of forming the staking portion <NUM> based on the torque measurement value.

In another example, it is possible to adopt a configuration of moving the pressing die <NUM> (and the cylinder attached spindle <NUM>) in the axial direction of the reference axis α instead of moving the hub unit bearing <NUM> (and the holder <NUM>) in the axial direction of the reference axis α as a configuration of relatively moving the pressing die <NUM> (and the cylinder attached spindle <NUM>) and the hub unit bearing <NUM> (and the holder <NUM>) in the axial direction of the reference axis α when forming the staking portion <NUM>.

In a modified example, it is possible to adopt a configuration in which the pressing die <NUM> (and the spindle <NUM>) can be rotationally driven about the rotation axis β using the rotational drive mechanism and the hub <NUM> (and the holder <NUM>) is supported to be rotatable about the reference axis α. When such a configuration is adopted, the pressing die <NUM> is rotationally driven about the rotation axis β without rotating the pressing die <NUM> about the reference axis α while pressing a part of the processing surface portion <NUM> in the circumferential direction in the pressing die <NUM> against a part of the processing object (the cylindrical portion <NUM>, the staking portion intermediary body <NUM>) in the circumferential direction when forming the staking portion <NUM>. Then, the hub <NUM> is rotated about the reference axis α based on a frictional force acting on the contact portion between the processing surface portion <NUM> and the processing object (the cylindrical portion <NUM>, the staking portion intermediary body <NUM>) in accordance with this operation. That is, in the above-described example, the processing object was processed by rotationally driving the hub <NUM> about the reference axis α while rotating the pressing die <NUM> about the rotation axis β in a following manner. In this example, it is possible to process the processing object by rotationally driving the pressing die <NUM> about the rotation axis β while rotating the hub <NUM> about the reference axis α in a following manner.

Another embodiment of the present invention will be described with reference to <FIG> and <FIG>.

In an embodiment, a device different from the staking device <NUM> shown in <FIG> is used as the staking device for performing the work of forming the staking portion <NUM>. In an embodiment, the staking device is obtained by adding a mechanism that changes the inclination angle θ of the rotation axis β with respect to the reference axis α to the staking device <NUM> shown in <FIG>. The mechanism that changes the inclination angle θ of the rotation axis β with respect to the reference axis α can be realized by, for example, an arc-shaped linear guide including an arc-shaped guide rail and a guide block moving along the guide rail. Specifically, the guide rail is fixed to the upper frame <NUM> and the guide block is fixed to the cylinder attached spindle <NUM> while the center of curvature of the arc-shaped guide rail is aligned to an intersection P between the reference axis α and the rotation axis β. When the cylinder attached spindle <NUM> and the pressing die <NUM> (rotation axis β) are swung about the intersection P by moving the guide block along the guide rail in this state, the inclination angle θ can be changed. Further, in an example, the mechanism that changes the inclination angle θ further includes an angle adjusting motor which is a drive source for swinging the cylinder attached spindle <NUM> and the pressing die <NUM> (rotation axis β) about the intersection P (adjusting the inclination angle θ). When carrying out the present invention, an appropriate mechanism different from the above one can be adopted as the mechanism that changes the inclination angle θ.

In an example, the first step of the work of forming the staking portion <NUM> is performed similarly to the case of the first example of the embodiment. In this example, a method of applying the processing force Fi directed downward in the up and down direction and directed radially inward from a part of the processing surface portion <NUM> in the circumferential direction to a part of the staking portion intermediary body <NUM> (the staking portion <NUM>) in the circumferential direction in the second step of the work of forming the staking portion <NUM> is different from the case of the embodiment.

That is, in this example, in the second step, the inclination angle θ of the rotation axis β with respect to the reference axis α is first increased by a predetermined amount (for example, about <NUM>° to <NUM>°) by swinging the pressing die <NUM> about the intersection P between the reference axis α and the rotation axis β in the direction of the arrow S2 as shown in part (A) of <FIG> based on the driving of the angle adjusting motor. Accordingly, as shown in part (A) and part (B) of <FIG>, and <FIG>, when forming the staking portion <NUM> from the staking portion intermediary body <NUM>, only the radially outer portion <NUM> in the processing surface portion <NUM> contacts the staking portion intermediary body <NUM> (the staking portion <NUM>) in the contact portion between the processing surface portion <NUM> and the axially inner surface of the staking portion intermediary body <NUM> (the staking portion <NUM>). Accordingly, the processing force Fi directed downward in the up and down direction and directed radially inward is applied from a part of the processing surface portion <NUM> in the circumferential direction to a part of the staking portion intermediary body <NUM> (the staking portion <NUM>) in the circumferential direction. Other configurations and effects can be the same as in the above-described embodiment.

The present invention can be carried out by appropriately combining the configurations of the above-described embodiments as long as there is no contradiction.

Additionally, when carrying out the present invention, it is possible to use a staking device different from those of the above-described embodiments, that is, a staking device (swaging device) including a rotating head which can be rotationally driven about the reference axis α (see <FIG>, <FIG>, and <FIG>) and supports the pressing die <NUM> to be rotatable about the rotation axis β, when forming the staking portion <NUM>. In such a swaging device, the pressing die <NUM> rotates (revolves) about the reference axis α as the rotating head rotates about the reference axis α. At this time, the pressing die <NUM> can rotate (revolve) about the rotation axis β. When the staking portion <NUM> is formed by using such a swaging device, the pressing die <NUM> is rotationally driven about the reference axis α together with the rotating head without rotating the hub <NUM> about the reference axis α while pressing a part of the processing surface portion <NUM> in the circumferential direction in the pressing die <NUM> against a part of the processing object (the cylindrical portion <NUM>, the staking portion intermediary body <NUM>) in the circumferential direction. The pressing die <NUM> rotates about the rotation axis β based on a frictional force acting on the contact portion between the processing surface portion <NUM> and the processing object (the cylindrical portion <NUM>, the staking portion intermediary body <NUM>). Accordingly, the application position of the processing force is continuously changed in the circumferential direction of the processing object (the cylindrical portion <NUM>, the staking portion intermediary body <NUM>) while applying the processing force to the processing object (the cylindrical portion <NUM>, the staking portion intermediary body <NUM>). Further, a mechanism that displaces the pressing die <NUM> in the axial direction of the rotation axis β or a mechanism that changes the inclination angle θ of the rotation axis β with respect to the reference axis α can be added to the above-described swaging device. When such a mechanism is added, the first step and the second step of the work of forming the staking portion <NUM> can be performed by using one swaging device as in the case of the above-described embodiments.

According to the invention, the staking portion <NUM> is formed in the hub main body <NUM> by swaging. The staking portion forming step includes a first step of deforming a part of the hub main body <NUM> radially outward by applying a load including a load component (second load component) directed radially outward to the hub main body <NUM> using the pressing die <NUM> by swaging and a second step of applying a load including a load component (first load component) directed radially inward to a radially outer portion of a deformed portion (staking portion intermediary body (intermediate staking portion) <NUM>) of the hub main body <NUM> using the pressing die <NUM> by swaging. In an example, at least one of swinging movements, positions (swing start position, swing end position), and postures (swing start posture, swing end posture) of the pressing die <NUM> differs from each other between the first step and the second step.

Claim 1:
A method of manufacturing a hub unit bearing (<NUM>) comprising the steps of:
preparing a pressing die (<NUM>) including a rotation axis (β) that is inclined with respect to a reference axis (α) and including a processing surface portion (<NUM>) formed by an inner surface of an annular concave portion centered on the rotation axis (β),
axially combining a first member (<NUM>) with a second member (22a), the second member (22a) having a hole into which the first member (<NUM>) is inserted in a direction along the reference axis (α); and
relatively rotating the first member (<NUM>) and the pressing die (<NUM>) with each other about the reference axis (α) to form a staking portion (<NUM>) by deforming a part of the first member (<NUM>) radially outward, wherein the step of forming the staking portion (<NUM>) includes:
a first step of applying a load including a load component directed radially outward to the first member (<NUM>) using a radially inner portion (<NUM>) of the annular concave portion (<NUM>) of the pressing die (<NUM>) to deform a part of the first member (<NUM>) radially outwards;
an intermediate step of: (a) displacing the pressing die (<NUM>) in an axial direction of the rotation axis (β); or (b) changing an inclination angle of the rotation axis (β) with respect to the reference axis (α); and
a second step of applying a load including a load component directed radially inward to a radially outer portion (<NUM>) of the first member (<NUM>) using a radially outer portion (<NUM>) of the annular concave portion (<NUM>) of the pressing die (<NUM>), while the radially inner portion (<NUM>) of the annular concave portion (<NUM>) does not contact the first member (<NUM>).