Patent Grant
7182676
The present invention relates to a machining apparatus and a machining method of machining an end face of a work, a roller provided by the machining method, and a roller bearing having the roller.
An end face of a work of a roller bearing slides on a rib on a side of a track ring and therefore, in order to reduce friction heat generated between the end face of the roller and the rib, as shown by
As a method of machining such a crowned face 2 at the end face of the roller 1, there is known a method of machining the end face of the roller by an elastic grinding wheel having Young's modulus of 10 MPa through 500 MPa by using a horizontal type double head surface grinder.
According to the method of machining an end face of a roller, the rollers are not machined piece by piece but the rollers can be machined at a high efficiency by continuous machining. Further, the roller can be machined smoothly without producing an edge at a portion of connecting the outer diameter face and a chamfer face 3, a portion of connecting the chamfer face 3 and the crowned face 2, and a portion of connecting the crowned face 2 and a plane portion of the end face of the roller (refer to, for example, Patent Reference 1).
In addition, there is provided a method of machining an face of a roller which allows the machining of an end face of a work while rotating the work and the machining of the end face of the roller at a high efficiency (refer to, for example, Patent References 2 and 3)
[Patent Reference 1]
Unexamined Japanese Patent Application Publication No. 2003-21145
[Patent Reference 2]
DE No. 2636689
[Patent Reference 3]
Japanese Patent No. 3455411
However, although according to Patent Reference 1, mentioned above, a smoothly continuous crowned shape can be continuously machined at the end face of the roller with a high efficiency, there is a drawback that accuracy of roller end face runout with outside surface is poor since rotation (self rotation) of the work is not stabilized.
On the other hand, according to Patent References 2 and 3, mentioned above, accuracy of swinging the end face of the roller can be improved since the end face of a work is machined while rotating the work. However, there is a drawback that shape differences in the end face of rollers after machining will be larger if such differences exist before machining since a machining tool is pressed to the end face of the work at a fixed position.
The present invention is carried out to eliminate the above-mentioned drawbacks. An object of the present invention is to provide a machining apparatus and a machining method of machining an end face of a work capable of continuously machining a smoothly continuous crowned shape at the end face of a roller with a high efficiency, improving accuracy of roller end face runout with outside surface, and reducing shape differences in an end face of rollers after machining, a roller, and a roller bearing.
The above-mentioned objects of the present invention are achieved the following configuration:
According to the invention, an end face of a work is machined using an elastic machining tool while rotating and revolving the work through a spindle. Therefore, the rotation of the work is kept stable and the accuracy of roller end face runout with outside surface can be improved. Further, the end face of works continuously provided by a charge and discharge unit is machined with an elastic machining tool. Therefore, a smoothly continuous crowned shape can be continuously machined at the end face of the roller with a high efficiency.
In addition, the machining tool is pressed to the end face of the works with a pressure unit at a fixed pressure for machining purposes. Therefore, the end face of works can be machined in a constant machining amounts without being affected by shape differences in the end face of works before machining. Shape differences in the end face of works after machining can also be reduced.
The embodiments according to the invention will be described below in details with reference to the drawings.
As shown in
As shown in
Further, by driving to rotate the inner disk 11 and the drive belt 15 in directions inverse to each other, a rotational movement is provided to the work 12 and by rotating the cage 14, a revolutional movement is provided to the work 12.
As shown in
As shown in
As shown in
Works 12 continuously supplied from the charge unit 51 are rotated and revolved via the spindle 50 and machined with the elastic cup grinding wheel 19 pressed to the end face of the works at a fixed pressure by means of the pressure unit 60. In this way, the end face can smoothly be machined without producing the edge at the portion of connecting the chamfer face 3 and the crowned face 2 and the portion of connecting the crowned face 2 and the plane portion of the end face of the work (refer to
The elastic deformation of the elastic cup grinding wheel 19 where the elastic cup grinding wheel 19 is in contact with the end face of the work 12 results in machining according to pressure distribution P shown in
In addition, the longer it is used for machining, the more worn the elastic cup grinding wheel 19 will be. The elastic cup grinding wheel 19 is pressed to the end face of the work 12. Even when worn, the elastic cup grinding wheel 19 can therefore machines the end face of the work 12 always at a constant machining force with stable machining amount and with little shape difference.
As shown in
The pressure slide table 61 is guided by a linear guide, an air slide, and the like and the slide resistance for the guide is set to a sufficiently small value respective to the elastic cup grinding wheel 19's force for machining the end face of a work and pressurizing force. The pressure actuator 62 supplies oil to or discharges oil from the right- or left-side oil chamber of a piston 62a through the hydraulic circuit 70 to drive the piston 62a and advance and retreat the pressure slide table 61.
The positioning slide table 63 is preferably used when increasing the service thickness of the elastic cup grinding wheel 19 via the small-stroke pressure slide table 61 or when accommodating a change in position where the work 12 is set on the spindle 50. If, for example, the elastic cup grinding wheel 19 becomes worn, the position of the operating pressure slide table 61 is kept fixed by controlling the positioning actuator 64 and adjusting the position of the positioning slide table 63, based on linear gauge 65 measurements.
The linear gauge 65 is used to measure the position of the pressure slide table 61 when machining the end face of the work and monitor the worn state of the elastic cup grinding wheel 19. Concretely, the worn state of the elastic cup grinding wheel 19 can be detected by calculating the difference between the measurements and reference values (for example, measurements for the pressure slide table 61 with a new elastic cup grinding wheel 19 pressed to the end face of a work 12) and the position of the positioning slide table 63. The time to replace the elastic cup grinding wheel 19 can also be determined from measurement taken by the linear gauge 65.
In addition, the elastic cup grinding wheel 19 requires grinding wheel grinding that involves natural blade appearance so as to maintain good machining bite thereof and continue correct machining. Unstable contact of the spindle grinding wheel unit 53 with a work 12 would cause uneven working surface and therefore irregularities in the working surface of the elastic cup grinding wheel 19, thus preventing the elastic cup grinding wheel 19 from machining the end face of the work with a correct accuracy. In this embodiment, a damping action is given to the pressure actuator 62 for driving the pressure slide table 61 to prevent the spindle grinding wheel unit 53 from contacting the work 12 in an unstable manner so that the spindle grinding wheel unit 53 cannot move rapidly.
As shown in
Concretely, the hydraulic circuit 70 is configured to provide oil from the pump P to the left-or right-side oil chamber of the pressure actuator 62 piston 62a through the operation of a main selector valve 71. The circuit 70 is also configured to discharge the oil from the right- or left-side oil chamber of the piston 62a to advance or retreat the pressure slide table 61. Between the main selector valve 71 and the pressure actuator 62, there are arranged in series two throttle valves (flow control valves with a check valve) with a wide throttle and two throttle valves with a narrow throttle (flow control valves with a check valve, a speed control section). Selector vales 74 are arranged in parallel for two throttle valves 73 with a narrow throttle.
When the elastic cup grinding wheel 19 is pressed to the end face of the work 12 at the start of machining and when the elastic cup grinding wheel 19 is retreated from the end face of the work 12 after the end of machining, each selector valve 74 is opened and switched to a circuit with a wide throttle, thereby moving the pressure slide table 61 and/or the spindle grinding wheel unit 53 quickly. During the continued machining of the end face of a work by the elastic cup grinding wheel 19, each selector valve 74 is closed and switched to a circuit with a narrow throttle, thereby providing a damping action to the movement of the pressure slide table 61.
Further, although in the case of a double head plane grinder, Young's modulus of the elastic grinding wheel is proper to be 10 MPa through 1000 MPa, different from a double head plane grinder in which a grinding wheel and a roller is in parallel with each other, when an angle is provided between the cup grinding wheel 19 and the roller 12 constituting the roller as described above, Young's ratio of the elastic grinding wheel is proper to be 50 Mpa through 1000 Mps which is slightly harder.
Here, in order to stably rotate the work 12 at inside of the pocket portion 13 of the cage 14, it is necessary to pertinently select peripheral speeds of the inner disk 11, the cage 14 and the drive belt 15.
When α=1, the work 12 is not brought into close contact with the cage 14. By selecting α to be smaller than 1, the work 12 is pressed to the cage 14 by rotating the inner disk 11, by rotating the drive belt 15 slightly slower than the work 12 driven by the cage 14 and the inner disk 11, brake is applied and an attitude of the work 12 is stabilized.
When α=1, the work 12 is not brought into close contact with the cage 14. By selecting a to be slightly larger than 1, the work 12 is pressed to the cage 14 by rotating the drive belt 15, by rotating the inner disk 11 slightly slower than the work 12 driven by the cage 14 and the drive belt 15, brake is applied and the attitude of the work 12 is stabilized.
Further, here, α is preferably about 1.01 through 1.10.
In this case, there may be established a relationship in which Vb=(Vi+2×Vc)×α and α>1.
In this case, there may be established a relationship in which Vb=(Vi−2×Vc)×α and α<1.
In this way, according to the embodiment, an end face of a work 12 is machined using an elastic machining tool 19 while rotating and revolving the work 12 through a spindle. Therefore, the rotation of the work 12 is kept stable and the accuracy of roller end face runout with outside surface can be improved. Further, the end face of works 12 continuously provided by a charge unit 51 is machined with an elastic machining tool 19. Therefore, a smoothly continuous crowned shape can be continuously machined at the end face of the roller with a high efficiency.
In addition, the elastic cup grinding wheel 19 is pressed to the end face of the works 12 with a pressure unit 60 at a fixed pressure for machining purposes. Therefore, the end face of works 12 can be machined in a constant machining amounts without being affected by shape differences in the end face of works 12 before machining. Shape differences in the end face of works 12 after machining can also be reduced.
Further, although according to a double head plane grinder of the background art, since rotation of the work 12 is not stabilized, a random machining mark remains at the end face of the roller after machining, according to the embodiment, since rotation of the roller 12 is stabilized, a machining mark in a spiral shape aligned in rotating direction is produced at the end face of the roller after machining.
Next, a machining apparatus of an end face of a work according to a second embodiment of the invention will be explained with reference to
As shown in
As shown in
Further, by driving to rotate the inner disk 31 and the drive belt 15 in directions reverse to each other, the work 12 is provided with a rotational movement and by rotating the cage 34, the work 12 is provided with a revolutional movement.
As shown by
As shown by
Further, according to the embodiment, the end face of the work 12 on one side is supported by the cage 34 and therefore, only the end face on one side of the work 12 can be machined. Although in order to machine the both end faces of the work 12, it is necessary to machine one sides thereof by using two sets of the kind of the apparatus, even when a length of the work 12 in the axial direction is short and the inner disk and the cage cannot be arranged as in the above-described first embodiment, no problem is posed according to the embodiment.
Works 12 continuously supplied from the charge unit 51 are rotated and revolved via the spindle 80 and machined with the elastic cup grinding wheel 19 pressed to the end face of the works at a fixed pressure by means of the pressure unit 60 shown in
Further, when the work 12 is rotated without machining the work 12 before starting to machine or after finishing to machine the end face of the work 12, there is a possibility that the work 12 comes out from the pocket portion 33, in order to press the work 12 stably to the bottom portion of the pocket portion 33 by preventing the work 12 from coming out from the pocket portion 33, as shown by
A machining apparatus of an end face of a work according to a third embodiment of the present invention will be explained below with reference to
In the machining apparatus according to the third embodiment, machining cannot be impossible with a proper accuracy in some cases if there is a large fluctuation in the working face of the grinding wheel of an elastic cup grinding wheel 19 immediately after grinding wheel replacement, for example. When there is a large fluctuation in the working face of the grinding wheel immediately after grinding wheel replacement, for example, the grinding wheel therefore requires dressing. As shown in
As shown in
When the elastic cup grinding wheel 19 worn during machining is dressed, the position of the positioning slide table 63 can be pre-determined based on the position of the pressure slide table 61 measured with a linear gauge 65 at the machining of the end face of the work 12, the positioning position and mechanical configuration dimensions of the positioning slide table 63, and the setting position of the preset dresser diamond 91. The other constitution and the operation and the effect are similar to those of the above-described second embodiment.
A machining apparatus of an end face of a work according to a fourth embodiment of the present invention will be explained below with reference to
As shown in
In the machining apparatus 100 according to the fourth embodiment, works 12 continuously supplied from one charge unit 51 (the right-side unit shown in
The two elastic cup grinding wheels 19 are aligned for adjustments so that they are slighted tilted with respect to the end face of the works rotated and revolved via the spindle 50 (80).
The rotation axis of the elastic cup grinding wheel 19 is first tilted by a predetermined angle θ1 with respect to the revolution axis of the work 12 (refer to
As shown in
In addition, the work 12 is, by the revolutional movement thereof, brought into contact with the entire working face of the elastic cup grinding wheel 19. This provides the wear of the entire working face of the grinding wheel, thus resulting in no remaining local unworn portion thereof. The other constitution and the operation and the effect are similar to those of the above-described first or second embodiment.
Further, the aligning adjustment according to the present invention is also applicable in the machining apparatus according to the above-mentioned embodiments.
Further, the machine apparatus of the end face of the work according to the invention is not limited to those of the above-described respective embodiments but can pertinently be modified or improved.
For example, although according to the above-described respective embodiments, there is shown an example of the case of using the elastic cup grinding wheel as an elastic tool, in place thereof, as shown by
In this case, as in the individual embodiments described above, works 12 continuously supplied from a charge unit 51 are rotated and revolved via the spindle 50 (80) and machined with the abrasive belt 40 pressed to the end face of the works 12 at a fixed pressure by means of the pressure unit 60. In this way, machining can be performed in the same way as with the elastic cup grinding wheel 19. The operation and the effect similar to those of the above-described first embodiment can be obtained. The abrasive belt 40 can adjust a machining force (normal line grinding resistance) by pertinently adjusting the tension, and can machine to follow the roller and therefore, machining can be carried by a crowned shape smoothly connected to the plane portion and the chamfer face of the end face.
Further, although according to the above-described respective embodiments, the cylindrical roller is exemplified as the roller to be machined, the invention is applicable also to a spherical roller.
Further, in the fourth embodiment, the pressure slide table can be used with the position side table to advance the machining tool. The pressure slide table may be used alone.
In addition thereto, materials, shapes, dimensions, modes, numbers, arranging locations and the like of the works, spindle, charge and discharge units, machining tools, pressure units, pressure slide tables, pressure actuators, speed control section, linear gauges, positioning slide tables, elastic cup grinding wheels, abrasive belts, dressing tools, inner disks, cages, drive belts exemplified in the above-described respective embodiments are arbitrary and not limited.
| Number | Date | Country | Kind |
|---|---|---|---|
| P.2004-073926 | Mar 2004 | JP | national |
| P.2005-037614 | Feb 2005 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2551568 | Roshong | May 1951 | A |
| 2754635 | Ortegren | Jul 1956 | A |
| 3859756 | Zerbola | Jan 1975 | A |
| 3889428 | Steinegger et al. | Jun 1975 | A |
| 4531327 | Dzewaltowski et al. | Jul 1985 | A |
| 5609514 | Yasunaga et al. | Mar 1997 | A |
| 6955583 | Dall'Aglio | Oct 2005 | B2 |
| Number | Date | Country |
|---|---|---|
| 26 36 689 | Aug 1976 | DE |
| 59-34502 | Feb 1984 | JP |
| 2002-86336 | Mar 2002 | JP |
| 2003-21145 | Jan 2003 | JP |
| 3455411 | Jul 2003 | JP |
| 08-074858 | Apr 2004 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20050233683 A1 | Oct 2005 | US |
