Patent Grant
10746230
This application is a National Stage of International Application No. PCT/JP2016/065879 filed May 30, 2016, claiming priority based on Japanese Patent Application No. 2015-114567, filed Jun. 5, 2015, the contents of all of which are incorporated herein by reference in their entirety.
The present invention relates to a method of manufacturing a rolling bearing unit for supporting a wheel in order to support a wheel of an automobile using a suspension system.
Priority is claimed on Japanese Patent Application No. 2015-114567, filed Jun. 5, 2015, the contents of which are incorporated herein by reference.
The outer ring 2 has a stationary side flange 5 formed on an outer circumferential surface thereof, and a plurality of rows of outer ring tracks 6a and 6b formed on an inner circumferential surface thereof. In addition, the hub 3 is formed by assembling a hub main body 7 and an inner ring 8. The hub main body 7 has a rotary side flange 9 formed on a portion of the hub main body 7 close to an outer end of an outer circumferential surface in an axial direction, an inner ring track 10a that is formed on an intermediate section of the hub main body 7 in the axial direction and that is disposed outside of the intermediate section in the axial direction, and a small diameter step section 11 formed on an inner end portion of the hub main body 7 in the axial direction. Further, “an axial direction,” “a radial direction” and “a circumferential direction” in the specification and claims are directions with respect to a hub main body unless the context clearly indicates otherwise. In addition, “an outer side” in the axial direction in the specification and claims represents an outer side in a widthwise direction of the vehicle when assembled to an automobile, that is, the left side of
The inner ring 8 has an inner ring track 10b that is formed on an outer circumferential surface thereof and formed inside in the axial direction, and the inner ring 8 is fastened and fitted onto the small diameter step section 11 of the hub main body 7. In addition, the plurality of rolling elements 4 and 4 is installed between the outer ring tracks 6a and 6b and the inner ring tracks 10a and 10b for each row in a rollable manner. In addition, in this state, a caulking section 13 is formed by plastically deforming a portion of a cylindrical section 12, formed on an inner end portion of the hub main body 7 in the axial direction, protruding from an inner end opening of the inner ring 8 in the axial direction outward in the radial direction. Then, an appropriate preload is applied to the rolling elements 4 and 4 as an inner end surface of the inner ring 8 in the axial direction is pressed by the caulking section 13.
When the rolling bearing unit 1 for supporting a wheel configured as described above is assembled, first, the outer ring 2 is disposed around the hub main body 7, and the rolling elements 4 and 4 are installed between the outer ring track 6a outside in the axial direction among the outer ring tracks 6a and 6b and the inner ring track 10a outside in the axial direction while being held by a retainer 14a outside in the axial direction. Next, the rolling elements 4 and 4 are installed around the inner ring track 10b inside in the axial direction formed on the outer circumferential surface of the inner ring 8 while being held by a retainer 14b inside in the axial direction, and in this state, the inner ring 8 is fastened and fitted onto the small diameter step section 11 formed on the inner end portion of the hub main body 7 in the axial direction. Then, according to the on-fitting work, rolling surfaces of the rolling elements 4 and 4 held by the retainer 14b inside in the axial direction abut the outer ring track 6a outside in the axial direction. Next, the caulking section 13 is formed by plastically deforming an inner end portion of the cylindrical section 12 of the hub main body 7 in the axial direction (a portion of the inner ring 8 protruding from an inner end opening in the axial direction) outward in the radial direction. Then, the inner ring 8 can be fixed to the hub main body 7 as the inner end surface of the inner ring 8 in the axial direction is suppressed in the axial direction by the caulking section 13.
The caulking section 13 configured to fix the inner ring 8 to the hub main body 7 is formed by, for example, a rotating and caulking process as disclosed in Patent Literatures 1 to 3. When the caulking section 13 is formed by the rotating and caulking process, for example, a rotating type caulking apparatus 15 as shown in
The caulking section 13 formed as described above applies an appropriate preload to the rolling elements 4 and 4 by pressing the inner end surface of the inner ring 8 in the axial direction. In order to apply a preload having an appropriate magnitude as described above, it is desirable that the caulking section 13 makes a force pressing the inner end surface of the inner ring 8 in the axial direction outward in the axial direction (an axial force) constant (stabilize it). For this reason, in the case of the rotating and caulking process is performed using the above-mentioned rotating type caulking apparatus 15, a load applied to the cylindrical section 12 by the mold 16 and the time for applying such a load are kept constant. However, in the case of such a method, a magnitude of the applied load and the time for applying the load may not be optimized for every workpiece (according to a difference in manufacturing error or property). That is, for example, depending on a variation or the like of a protrusion amount (a protrusion length) of a portion of the cylindrical section 12 protruding from the inner end opening of the inner ring 8 in the axial direction based on the manufacturing error, there is a possibility that a load larger than a load required for applying a preload having a desired magnitude needs to be applied or the time for applying the load needs to be excessively increased.
[Patent Literature 1]
Japanese Unexamined Patent Application, First Publication No. 2010-175079
[Patent Literature 2]
Japanese Unexamined Patent Application, First Publication No. 2000-317552
[Patent Literature 3]
Japanese Unexamined Patent Application, First Publication No. 2002-081453
An object of the present invention is to provide a manufacturing method capable of optimizing a processing time for caulking of each workpiece.
In an aspect of the present invention, a rolling bearing unit for supporting a wheel includes a hub main body and an inner ring. The hub main body has an outer-side inner ring track formed on an outer circumferential surface of an intermediate section of the hub main body in an axial direction. In addition, the inner ring has an inner-side inner ring track formed on an outer circumferential surface of the inner ring and is fitted onto a portion of the hub main body close to an inner end of the hub main body in the axial direction. The inner ring is fixed to the hub main body by pressing an inner end surface of the inner ring in the axial direction with a caulking section formed by plastically deforming a cylindrical section, installed on an inner end portion of the hub main body in the axial direction (a portion of the cylindrical section protruding from an inner end opening of the inner ring in the axial direction), outward in a radial direction.
In the method of manufacturing a rolling bearing unit for supporting a wheel of the present invention, the caulking section is formed by pressing a roll, supported in a rotatable state about a central axis of the roll which is inclined with respect to a central axis of the hub main body, against the cylindrical section while the roll is rotated about a central axis of the hub main body by an electric motor. In addition, the method of manufacturing a rolling bearing unit for supporting a wheel of the present invention includes detecting a rotational torque generated by the electric motor or a physical amount having a correlation with the rotational torque during a caulking process for forming the caulking section, and determining a condition for terminating the caulking process on the basis of the detection result.
In an example, a current value of the electric motor may be employed as the physical amount.
In an example, a configuration in which the caulking process is terminated after a predetermined time elapses from a time point at which a magnitude of the rotational torque or the physical amount has decreased at a change ratio of a predetermined value or more may be employed.
In an example, a configuration in which the caulking process is terminated under a condition in which a change ratio of the rotational torque or the physical amount converges within a predetermined range after a magnitude of the rotational torque or the physical amount has decreased at a change ratio of a predetermined value or more may be employed. Specifically, the caulking process is terminated when a magnitude of the rotational torque or the physical amount stays in the predetermined range for a predetermined time or more.
According to the aspect of the present invention, it is possible to provide a manufacturing method capable of optimizing a processing time for caulking of each workpiece.
A first embodiment of the present invention will be described with reference to
The rotating type caulking apparatus 15a used in the manufacturing method of the first embodiment includes, as shown in
The electric motor 19 is constituted by, for example, an inverter and an induction motor in order to adjust a rotational speed. In addition, a servo motor may be used as the electric motor. In addition, a DC motor or a stepping motor may be used as the electric motor. The electric motor 19 is supported by a housing (not shown).
In the spindle 20, one end portion of the spindle 20 in the axial direction (an upper end portion of the spindle 20 in
The roll holding part 21 has a substantially hexagonal cross section, and is constituted by a columnar section 24 formed on a base end-side half section (an upper half section of the roll holding part 21 in
The columnar section 24 has an outer diameter dimension that is larger than an outer diameter dimension of the spindle 20. The columnar section 24 couples and fixes one end portion of the columnar section 24 in the axial direction (an upper end portion of the columnar section 24 in
The partial conical section 25 is formed in a state in which an outer diameter dimension thereof increases toward one side of the partial conical section 25 in the axial direction. The partial conical section 25 is formed integrally and coaxially with the columnar section 24 at the other end side of the columnar section 24 in the axial direction.
The roll holding part 21 having the above-mentioned configuration has a holding concave section 26 formed from the partial conical section 25 to a portion close to the other end of the columnar section 24 in the axial direction. Specifically, the holding concave section 26 has a cylindrical inner circumferential surface, and the holding concave section 26 is formed in the other end surface of the partial conical section 25 (the roll holding part 21) in the axial direction in a state that the holding concave section 26 is fitted in a recess at one side of the roll holding part 21 in the axial direction from the other end surface in the axial direction. A holding concave section 21 is formed in a state in which a central axis β21 is inclined with respect to an output shaft of the electric motor 19, the central axis α20 of the spindle 20 and a central axis of the roll holding part 21 by a predetermined angle θ (for example, about 5 to 30 degrees).
The roll 22 is a shaft-shaped member, and is constituted by a support section 27 and a caulking forming section 28.
The support section 27 has a stepped shaft shape constituted by a small diameter shaft section 29 and a large diameter shaft section 30. The small diameter shaft section 29 has a columnar shape in which an outer diameter dimension does not vary throughout the length of the roll 22 in the axial direction. The small diameter shaft section 29 is formed on a portion of the support section 27 from a portion of the roll 22 closer to one end in the axial direction to the one end of the roll 22 in the axial direction (an upper end of the roll 22 in
The large diameter shaft section 30 has a columnar shape in which an outer diameter dimension does not vary throughout the length of the roll 22 in the axial direction. The large diameter shaft section 30 is formed on a portion of the support section 27 closer to the other end of the roll 22 in the axial direction (a lower end of the roll 22 in
The caulking forming section 28 has a substantially columnar shape in which an outer diameter dimension is larger than that of the large diameter shaft section 30 of the support section 27. A caulking forming concave groove 31 is formed in an intermediate section of the caulking forming section 28 in the radial direction among the other end surface of the caulking forming section 28 in the axial direction in a state being recessed toward one side of the caulking forming section 28 in the axial direction from the other end surface in the axial direction throughout the circumference. A cross-sectional shape of the caulking forming concave groove 31 with respect to a virtual plane passing through the central axis of the roll 22 has a concave arc shape having a deepest part in the central portion thereof with respect to the roll 22 in the radial direction. Further, the caulking forming section 28 and the support section 27 may be divided and may be consisted to be detachable. According to the above-mentioned configuration, when the caulking forming section 28 should be exchanged with a new one due to abrasion, it is possible to exchange the caulking forming section 28 only, and processing cost and material cost of the roll 22 can be decreased.
The roll 22 configured as described above is held while being rotated (self-rotation) about the central axis β22 thereof inside the holding concave section 26 of the roll holding part 21. Specifically, the small diameter shaft section 29 of the support section 27 that constitutes the roll 22 is inserted into a ring-shaped holding member 32 having a circular ring shape. The ring-shaped holding member 32 is fitted into and fixed to a back end portion of the holding concave section 21. In addition, in this state, the large diameter shaft section 30 of the support section 27 that constitutes the roll 22 is fitted into a sleeve 33 via a pair of rolling bearings 34a and 34b in a state in which rotation thereof with respect to the sleeve 33 is possible. The sleeve 33 is fitted into and fixed to an intermediate section of the holding concave section 21 in the axial direction. In addition, in this state, a half section of the other end surface of the roll 22 in the axial direction on the side of an inclined direction of the central axis β22 of the roll 22 with respect to the central axis α20 of the spindle 20 protrudes closer to the other side of the roll holding part 21 in the axial direction than the other end surface of the roll holding part 21 in the axial direction.
The pressing device 23 is provided for pressing the roll 22 downward. The pressing device 23 is constituted by a pump (not shown) and a hydraulic cylinder 35. The hydraulic cylinder 35 supports the spindle 20 at an inner side thereof in a state that the spindle 20 is rotatable about the central axis α20 of the spindle 20 and is displaceable in the axial direction of the central axis α20. In addition, the hydraulic cylinder 35 displaces the spindle 20 toward the other side in the axial direction (a lower side of
When an inverter is used to drive and control the electric motor 19, since a current measuring device included in the inverter can be used, there is no particular need to install the current measuring device. In addition, when a servo motor is used as the electric motor 19, since a current measuring device is included in a motor driver in many cases, there is no particular need to install the current measuring device in this case. Meanwhile, when the inverter is not used to drive and control the electric motor 19 or when the servo motor including the current measuring device is not used, various means known in the related art can be employed as the current measuring device configured to measure a current flowing through the electric motor 19.
Next, a method of manufacturing a rolling bearing unit for supporting a wheel of the example performed using the rotating type caulking apparatus 15a having the above-mentioned configuration will be described.
The method of manufacturing a rolling bearing unit for supporting a wheel of the embodiment is characterized in that caulking for forming the caulking section 13 is performed by plastically deforming a portion of the cylindrical section 12 formed on an inner end portion of a hub main body 7 in the axial direction protruding from an inner end opening of an inner ring 8 in the axial direction outward in the radial direction.
The method of manufacturing a rolling bearing unit for supporting a wheel of the embodiment is provided in a state in which the outer ring 2 is disposed around the hub main body 7 and the rolling elements 4 and 4 are held between the outer ring track 6a outside in the axial direction among both of the outer ring tracks 6a and 6b and the inner ring track 10a outside in the axial direction by using the retainer 14a (see
Next, in a state in which the inner end side in the axial direction is directed upward on, the intermediate assembly is fixed to a fixing section 39 of a fixing table 38 that constitutes the rotating type caulking apparatus 15a. In this state, the central axis α7 of the hub main body 7 that constitutes the intermediate assembly is concentric with the central axis α20 of the spindle 20.
Next, the electric motor 19 is rotated and driven at a predetermined rotational speed (a constant rotational speed) to rotate and drive the spindle 20, the roll 22 is displaced downward in this state, and a portion of the caulking forming concave groove 31 of the roll 22 is made to abut a portion of the cylindrical section 12 of the hub main body 7 in the circumferential direction. Then, from this state, the caulking forming concave groove 31 of the roll 22 is pressed downward toward the inner end surface of the cylindrical section 12 in the axial direction by the pressing device 23 with a predetermined force. In this state, the roll 22 rotates about the central axis α20 of the spindle 20 (precessionally moves around the central axis of the hub main body 7). Then, since the roll 22 is rotatably held by the holding concave section 26 of the roll holding part 21, the roll 22 rotates about the central axis α22 thereof on the basis of friction of the abutting section between the caulking forming concave groove 31 of the roll 22 and the cylindrical section 12.
Next, a state of plastic deformation of the cylindrical section 12 when the caulking section 13 is formed in the cylindrical section 12 of the hub main body 7 through such caulking will be described with reference to
First, when the caulking forming section 28 of the roll 22 abuts the cylindrical section 12 to press the cylindrical section 12 downward in the above mentioned way, the inner end surface of the cylindrical section 12 in the axial direction (the upper end surface of the cylindrical section 12 in
When caulking further advances from the state shown in
In the state shown in
In the state shown in
In the case of the manufacturing method of the embodiment, during the caulking such as mentioned above, a magnitude of the current flowing through the electric motor 19 is measured by the current measuring device. Further, the current generally flowing through the electric motor and the rotational torque generated by the electric motor have a correlation (a proportional relation), and the rotational torque generated by the electric motor can be obtained on the basis of the measured current value flowing through the electric motor. Here, while loss of the motor such as iron loss, and an influence of slippage are considered, it is usually negligible. That is, in the case of the embodiment, the current flowing through the electric motor 19 measured by the current measuring device corresponds to a physical amount. Further, in addition to the current flowing through the electric motor 19, a rotational speed of the electric motor 19 or a portion rotated synchronously with the electric motor 19 {a rotational speed decreases (increases) when a torque required for caulking at a constant voltage and current increases (decreases)}, an electric power measured by attaching an ammeter (an electric power increases when a torque increases), and so on, can be employed as physical amounts. In addition, for example, a method of installing a torque sensor on the spindle 20 to directly measure a torque may be employed.
In the case of the embodiment, since the electric motor 19 is rotated and driven at a constant rotational speed, a magnitude of the current flowing through the electric motor 19 is changed according to a magnitude of the rotational torque generated in the abutting section between the cylindrical section 12 and the roll 22.
Then, in the case of the embodiment, a condition (timing) of terminating the caulking is determined on the basis of a current value (a rotational torque) measured by the current measuring device.
Hereinafter, a method of determining a timing of terminating caulking will be described on the basis of a current value (a rotational torque) measured by the current measuring device.
First, during the above-mentioned caulking, a relation between the current value flowing through the electric motor 19 and the processing time measured from the driving of the electric motor 19 to the state of
In the diagram shown in
In addition, in a portion shown by (II) in
[Math. 1]
Ta=S·Y·R (1)
[Math. 2]
T=TS+Ta (2)
In the portion shown by (II) in
In addition, in a portion shown by (III) in
In addition, in a portion shown by (IV) in
In addition, in a portion shown by (V) in
In addition, in a portion shown by (VI) in
In addition, in a portion shown by (VII) in
In the case of the manufacturing method of the embodiment, a timing of terminating the caulking is determined on the basis of the current value measured by the current measuring device as described above or the rotational torque obtained based on the current value. Specifically, in the case of the embodiment, like the portion shown by (V) in
According to the method of manufacturing a rolling bearing unit for supporting a wheel of the embodiment configured as above, optimization of the processing time of the caulking of each workpiece is achieved.
That is, in the case of the embodiment, during caulking for forming the caulking section 13, a current value flowing through the electric motor 19 is detected, and a time consumed to terminate the caulking is determined on the basis of a state of the current value obtained by the detection or the rotational torque obtained from the current value. Specifically, as described above, like the portion shown by (V) in
A second embodiment of the present invention will be described with reference to
In particular, in the case of the embodiment, after the caulking is started and the current value or the rotational torque obtained from the current value increases as shown by (II) to (IV) in
In the above-mentioned embodiments, the rotational torque generated by the electric motor during the caulking is obtained from the current value flowing through the electric motor. However, for example, a rotational torque may be directly measured by a so-called magneto-striction type torque sensor or the like installed on an output shaft of the electric motor or a spindle coupled and fixed to the output shaft.
In addition, the pressing device that constitutes the rotating type caulking apparatus is not limited to the structure of each of the above-mentioned embodiments. For example, like the pressing device 23a that constitutes the rotating type caulking apparatus 15b shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-114567 | Jun 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/065879 | 5/30/2016 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2016/194866 | 12/8/2016 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4698992 | Bernet | Oct 1987 | A |
| 6363799 | Toda et al. | Apr 2002 | B1 |
| 7832940 | Matsui | Nov 2010 | B2 |
| 8631581 | Sera | Jan 2014 | B2 |
| 20030185479 | Toda | Oct 2003 | A1 |
| 20030213128 | Kaimi et al. | Nov 2003 | A1 |
| 20050126005 | Yasumura et al. | Jun 2005 | A1 |
| 20120119686 | Bertotto | May 2012 | A1 |
| 20160263940 | Hagiwara | Sep 2016 | A1 |
| Number | Date | Country |
|---|---|---|
| 1813139 | Aug 2006 | CN |
| 101035995 | Sep 2007 | CN |
| 2 722 548 | Apr 2014 | EP |
| 11-044319 | Feb 1999 | JP |
| 2000-317552 | Nov 2000 | JP |
| 2001-3945 | Jan 2001 | JP |
| 2001003945 | Jan 2001 | JP |
| 2001-050832 | Feb 2001 | JP |
| 2002-081453 | Mar 2002 | JP |
| 2003-028179 | Jan 2003 | JP |
| 2005-36905 | Feb 2005 | JP |
| 2005036905 | Feb 2005 | JP |
| 3930675 | Jun 2007 | JP |
| 2010-175079 | Aug 2010 | JP |
| 2015-077616 | Apr 2015 | JP |
| Entry |
|---|
| Machine Translation of JP2001003945A (Year: 2001). |
| Machine Translation of JP-3930675-B2 (Year: 2007). |
| Machine Translation of JP-2005036905-A (Year: 2005). |
| International Search Report for PCT/JP2016/065879, dated Aug. 16, 2016. |
| Search Report dated Nov. 2, 2018 from the State Intellectual Property Office of the P.R.C. in application No. 2016800322360. |
| Communication dated Dec. 20, 2018 from European Patent Office in counterpart EP Application No. 16803301.7. |
| Communication dated Feb. 20, 2018 from European Patent Office in counterpart EP Application No. 16803301.7. |
| Number | Date | Country | |
|---|---|---|---|
| 20180149206 A1 | May 2018 | US |
