JP2020075312A - Turning device and turning method - Google Patents

Abstract

To process an inner periphery and an outer periphery of a work-piece perfectly coaxially when turing, and to reduce strain in a radial direction of the work-piece when clamping.SOLUTION: A turning device comprises: a spindle 11 which rotates around an axis; a first holding part 12 which is located at an end part on an axial one side of the spindle 11 with a direction of the axis as an axial direction, and holds a work-piece 90 substantially coaxially with the spindle 11; a contact part 22 which is located on axial one side of the work-piece 90, and contacts the work-piece 90 in the axial direction; and a second holding part 24 which so holds the contact part 22 as to be capable of advancing toward and retracting from the work-piece 90 in the axial direction. The contact part 22 contacts the work-piece 90 and energizes the work-piece 90 toward axial other side when processing an outer peripheral surface of the work-piece 90, and retracts from the work-piece 90 while the first holding parts holds the work-piece 90 when processing an inner peripheral surface of the work-piece 90.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a turning apparatus and a turning method for processing an annular work by turning.

  An annular part such as an inner ring or an outer ring of a rolling bearing is usually subjected to finishing processing by grinding after passing through each step of turning and heat treatment. However, in order to reduce the manufacturing cost, the finishing process may be replaced with the grinding process and the turning process using a processing device such as a lathe may be performed.

  Parts such as the inner ring and the outer ring are required to be machined so that the inner peripheral surface and the outer peripheral surface are coaxial with high accuracy. When the finishing process is performed by the grinding process, since the resistance during the process is small, the work can be fixed using a magnet chuck or an air chuck. Therefore, by fixing the end surface of the work so that the clamp does not project on the surface to be processed, the inner peripheral surface and the outer peripheral surface can be processed simultaneously, and the inner peripheral surface and the outer peripheral surface can be processed coaxially with high accuracy. it can.

However, the turning process has a large resistance at the time of working, so that a stronger fixing method is required. Specifically, the inner peripheral surface 92 and the outer peripheral surface 93 of the annular work 90 are machined by cutting using a machining apparatus as shown in FIGS. 5 and 6. In FIG. 5, as the first step, the work 90 is fixed by a plurality of clampers 91 provided on the outer peripheral side of the work 90, and the inner peripheral surface 92 is processed. In this clamping method, since the clamper 91 covers the outer peripheral surface 93, it is impossible to process the outer periphery in the same state after processing the inner periphery. Therefore, the work 90 is once removed from the processing apparatus, and as a second step, the inner circumference of the work 90 is re-clamped by the collet chuck 94 to process the outer peripheral surface 93, as shown in FIG.
Even if the outer peripheral surface 93 of the workpiece 90 is machined in the first step, the collet chuck 94 covers the inner peripheral surface 92. Therefore, after machining the outer periphery, the inner periphery is left as it is. It cannot be processed. Therefore, in the second step, the work 90 needs to be re-clamped.

JP-A-1-135404

  In the turning process, the work 90 is processed coaxially with the main shaft of the lathe. Therefore, in order to machine the inner circumference and the outer circumference coaxially, when the workpiece 90 is clamped in the second step, the inner peripheral surface 92 machined in the first step becomes completely coaxial with the spindle of the lathe. Need to be fixed. However, there are variations in the fixing state when the work 90 is clamped, and the shaft of the work 90 is fixed to the main shaft of the lathe with some mounting error. For this reason, it has been extremely difficult to finish the inner peripheral surface 92 and the outer peripheral surface 93 completely coaxially.

  Further, when the outer peripheral surface 93 is processed by turning, a hard skiving method may be used in order to improve the accuracy of the finished surface or shorten the processing time. In the hard skiving method, the contact width between the tool and the work 90 is enlarged, and the cutting resistance is further increased as compared with the normal turning process. Therefore, when fixing the work 90, a mechanical clamp device with a large gripping force is used. used. However, when a plurality of circumferential positions are clamped like a three-jaw chuck, the work 90 may elastically deform into a polygonal shape. In this case, when the work 90 is removed from the processing device at the end of processing, the circularity of the work 90 may be deteriorated by elastically restoring the original shape.

  In view of the above situation, the present invention, when processing an annular work by cutting, the inner circumference and the outer circumference of the work can be processed completely coaxial, further, attracted by magnetic force or air. It is an object of the present invention to provide a turning apparatus and a turning method capable of reducing the radial strain even if the work is clamped more firmly than the method.

  One form of the present invention is a turning device that processes an annular work by cutting, and includes a main shaft that rotates about an axis and an end of the main shaft on one side in the axial direction with the direction of the shaft as the axial direction. And a contact portion disposed on one side of the workpiece in the axial direction and contacting the workpiece in the axial direction, and a contact portion. A second holding portion that holds the workpiece so as to be able to advance and retreat in the axial direction toward the workpiece, and the abutting portion abuts the workpiece when the outer peripheral surface of the workpiece is machined. Is urged toward the other side in the axial direction, and when the inner peripheral surface of the work is machined, the first holding portion retracts from the work while holding the work.

  Another aspect of the present invention is a turning method for processing an annular work by cutting, which comprises a main shaft rotating about an axis and an end of the main shaft on one side in the axial direction with the direction of the shaft as the axial direction. And a contact portion disposed on one axial side of the workpiece for axially contacting the workpiece, the first retaining portion being installed on the workpiece portion to hold the workpiece substantially coaxially with the spindle. A step of fixing the work to the first holding part by using a turning device including a second holding part that holds the part toward the work so as to be able to advance and retreat in the axial direction; An outer periphery processing step of processing the outer periphery of the work in a state where the portion is in contact with the work and urges the work toward the other side in the axial direction, and a state in which the first holding portion holds the work. In addition, an inner peripheral processing step of processing the inner periphery of the work by retracting the contact portion from the work is also provided.

  According to the present invention, when processing an annular work by cutting, the inner circumference and the outer circumference of the work can be processed completely coaxially, and the work is stronger than the method of adsorbing with magnetic force or air. It is possible to provide a turning apparatus and a turning method that do not deform the workpiece even when clamped to and can reduce radial strain. Further, since the work can be firmly fixed, the hard skiving method can be used when processing the outer peripheral surface. This improves the accuracy of the finished surface of the work.

It is an axial direction sectional view of a turning device which is one form of the present invention. It is an axial sectional view of a tapered roller bearing including an inner ring which is a workpiece. It is the side view which looked at the turning apparatus of FIG. 1 from the axial direction. It is a principal part enlarged view which shows the contact part in FIG. It is a schematic diagram which shows the workpiece clamping method at the time of the conventional inner periphery processing. It is a schematic diagram which shows the workpiece clamping method at the time of the conventional outer peripheral processing.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an axial cross-sectional view of a turning apparatus 10 that is one embodiment (hereinafter, this embodiment) of the present invention. FIG. 1 shows a state in which the inner ring of the tapered roller bearing is being turned. The turning apparatus 10 is, for example, a turning unit incorporated in a machining center, in which a machining material (hereinafter, a work 90) is clamped at a shaft end of a main spindle 11 and a cutting tool such as a chip attached to a tool holder (shown in the drawing). The surface of the work 90 is cut. In the following description, the direction of the axis m of the main shaft 11 is referred to as the axial direction, the direction orthogonal to the axis m is referred to as the radial direction, and the direction around the axis m is referred to as the circumferential direction.

First, the inner ring 82 manufactured by processing the workpiece 90 as the workpiece will be described. FIG. 2 is an axial sectional view of a tapered roller bearing 80 having the inner ring 82 as a component.
The tapered roller bearing 80 includes an outer ring 81, an inner ring 82, and a plurality of tapered rollers 83. The outer ring 81 and the inner ring 82 are each made of a steel material such as bearing steel. An outer raceway surface 84 formed of a conical surface is formed on the inner circumference of the outer ring 81, and an inner raceway surface 85 formed of a conical surface is formed on the outer circumference of the inner ring 82. A plurality of tapered rollers 83 are rotatably incorporated between the outer raceway surface 84 and the inner raceway surface 85, and the inner ring 82 can rotate with respect to the outer ring 81.

When a load is applied to the tapered roller bearing 80, the tapered roller 83 rolls while being strongly pressed against the raceway surfaces 84 and 85. For this reason, the inner ring 82 and the outer ring 81 are heat-treated and hardened to a hardness of about 60 HRC to prevent fatigue damage such as peeling from occurring on the raceway surfaces 84 and 85.
A small collar 86 having a diameter slightly larger than that of the inner raceway surface 85 is formed on the smaller diameter side of the inner raceway surface 85. Further, a large collar 87 having a diameter larger than that of the inner raceway surface 85 is formed on the larger diameter side of the inner raceway surface 85. The side surface of the large rib 87 on the inner raceway surface 85 side comes into contact with the end surface of the tapered roller 83, and serves as a guide surface 88 when the tapered roller 83 rolls in the circumferential direction.
The end faces of the inner ring 82 and the outer ring 81 on both sides in the axial direction are each formed by a plane orthogonal to the axis. In the following description, the end face of the inner ring 82 on the large brim 87 side is referred to as the large end face 78, and the end face of the small brim 86 side is referred to as the small end face 79.

Although not shown, the tapered roller bearing 80 is usually used in a form in which the outer circumference of the outer ring 81 is fitted to the inner circumference of the shaft box and the shaft is fitted to the inner circumference of the inner ring 82. It is rotatably supported by.
In such a shaft support structure, the shaft is rotated by reducing the coaxiality between the outer peripheral surface 71 of the outer race 81 and the outer raceway surface 84 and the coaxiality between the inner peripheral surface 72 of the inner race 82 and the inner raceway surface 85. It is possible to suppress whirling when doing. When the coaxiality is poor (when the value of coaxiality is large), the whirling of the shaft becomes large, so that large vibration and noise are generated during rotation. Further, by reducing the circularity of the outer raceway surface 84 and the inner raceway surface 85, the rotational accuracy of the tapered roller bearing 80 can be improved to reduce noise and vibration, and the contact stress generated on each raceway surface can be reduced. Can be reduced to improve the rolling life of the tapered roller bearing 80.
As described above, in the processing device for processing the annular work 90 such as the inner ring 82 and the outer ring 81 of the tapered roller bearing 80, the coaxiality between the outer circumference and the inner circumference is reduced, and the circularity of the inner circumference and the outer circumference is reduced. There is a demand for high-precision processing capability.

Next, the turning apparatus 10 will be described with reference to FIG.
The turning apparatus 10 includes a main shaft 11 that holds and rotates a work 90, and a clamp device 20 that axially presses the work 90.

Although not shown, the main shaft 11 is supported by rolling bearings such as angular ball bearings and tapered roller bearings, is rotatable about the axis m, and cannot be displaced in the axial direction.
A magnet chuck 12 (first holding unit) that holds the work 90 is attached to one end of the main shaft 11 in the axial direction. Hereinafter, in FIG. 1, the side where the magnet chuck 12 is attached to the main shaft 11 (the left side in the figure) is referred to as one side in the axial direction, and the opposite side (the right side in the figure) is the other side in the axial direction. That. A work attachment surface 13 for fixing the work 90 is formed on one side of the magnet chuck 12 in the axial direction in a direction orthogonal to the axis m. The magnet chuck 12 can adsorb and fix the work 90 made of an iron-based material to the work mounting surface 13 by an electromagnet built therein.
In FIG. 1, the work 90 is fixed to the work mounting surface 13 via a steel backing plate 14. The backing plate 14 has an annular shape, and a surface that abuts the work mounting surface 13 and a surface that abuts the work 90 are parallel to each other. The work 90 is fixed substantially coaxially with the main shaft 11 in a direction in which the large end surface 78 contacts the backing plate 14.

Next, the clamp device 20 will be described with reference to FIGS. 1 and 3. FIG. 3 is a side view of the turning apparatus 10 of FIG. 1 as viewed in the axial direction from one side in the axial direction to the other side in the axial direction, and shows how the support arm 21 is displaced.
The clamp device 20 is a device that further firmly holds the work 90 by pressing the work 90 fixed to the magnet chuck 12 in the axial direction. The clamp device 20 includes an abutting portion 22 that abuts the workpiece 90, and a swing support base 24 (second holding portion) that holds the abutting portion 22.
The swing support base 24 has a support arm 21 and a rotation shaft 23. The rotary shaft 23 is supported by a rolling bearing (not shown) such as a tapered roller bearing inside the housing 26, and is installed parallel to the main shaft 11. The support arm 21 is arranged in the axial direction of the rotary shaft 23. It is fixed to one end and extends radially outward. The rotary shaft 23 is rotatable about the axis n and is not axially displaceable with respect to the housing 26.

The contact portion 22 is attached to the end portion of the support arm 21 on the side away from the rotation shaft 23 in a direction in which the axis k is parallel to the axis n. The distance between the axis k of the contact portion 22 and the axis n of the rotating shaft 23 is equal to the distance between the axis m of the main shaft 11 and the axis n of the rotating shaft 23.
The contact portion 22 rotates about the axis n in a plane orthogonal to the axis n as the rotation shaft 23 rotates. Further, as can be seen from FIG. 1, the abutting portion 22 is arranged at a position displaced to one side in the axial direction with respect to the work 90, and when the rotating shaft 23 rotates, as shown in FIG. It can be arranged at a position coaxial with (position indicated by A in FIG. 3) or can be retracted to a position radially separated from the work 90 (position indicated by B in FIG. 3).

The swing support 24 is mounted on the pedestal 15 of the machining center so that it can slide in the axial direction. As a result, the contact portion 22 is held so as to be movable back and forth in the axial direction with respect to the work 90. As means for axially displacing the swing support base 24, mechanical displacement means using a cam or the like, or a feed device such as a ball screw is preferably used.
The pedestal 15 is provided with a positioning pin 16 protruding in the axial direction, and the support arm 21 is provided with a reference hole 25 penetrating in the axial direction. When the reference hole 25 and the positioning pin 16 are aligned in the axial direction, the contact portion 22 is arranged coaxially with the axis m.

  When processing the workpiece 90, the rotary shaft 23 rotates and the reference hole 25 and the positioning pin 16 are axially aligned. In this state, the swing support base 24 moves to the other side in the axial direction, the positioning pin 16 is inserted into the reference hole 25, and the contact portion 22 contacts the work 90 in the axial direction. .. A chamfer is provided at the tip of the positioning pin 16 so that the diameter thereof decreases toward one side in the axial direction, and the reference hole 25 is guided by the chamfer to easily fit with the positioning pin 16. Can be combined.

  The contact portion 22 will be described in detail with reference to FIG. FIG. 4 is an enlarged view of an essential part of FIG. 1, showing an axial cross section including the contact portion 22. A disk-shaped face plate 30 of the contact portion 22 is supported by a centering mechanism 31 and a support bearing 32.

  The face plate 30 has a configuration in which an attachment 33 that abuts the work 90 and a face plate base 34 that holds the attachment 33 are integrally combined by a bolt 35. The attachment 33 has a disc shape, and a contact surface 36 that comes into contact with the work 90 is formed in a plane shape in a direction substantially orthogonal to the axis m. Further, the diameter dimension of the contact surface 36 is larger than the diameter dimension of the end surface on one side in the axial direction of the work 90 (in this embodiment, the small end surface 79 of the inner ring 82), and contacts the work 90 over the entire circumference. By removing the bolts 35, the attachment 33 can be easily replaced with one having an appropriate size according to the workpiece 90 to be processed.

  The centering mechanism 31 includes a pin 37 and a case 38 that holds the pin 37.

  The pin 37 has a form in which a screw portion 39 and a head portion 40, and an intermediate shaft portion 41 provided between the screw portion 39 and the head portion 40 are coaxially arranged and integrally combined. The intermediate shaft portion 41 has a substantially square cross section in a direction orthogonal to the axis m. The screw portion 39 is arranged on the other axial side of the pin 37, and is screwed into a screw hole formed in the center of the face plate base 34. The end surface of the intermediate shaft portion 41 on the side of the screw portion 39 abuts the face plate base 34 in the axial direction, and the pin 37 and the face plate 30 are firmly fixed. The head portion 40 is in the shape of a disc having a larger diameter than the intermediate shaft portion 41, and the end surface 42 on the one axial side is formed as a spherical surface convex on the one axial side.

The case 38 includes a base member 43 that axially contacts the head 40 of the pin 37, and a holding member 44 that holds the head 40 of the pin 37.
The base member 43 is integrally formed with a screw shaft 45 extending to one side in the axial direction. The holding member 44 has a through hole 46 through which the intermediate shaft portion 41 of the pin 37 penetrates in the axial direction. The through hole 46 has a substantially square cross section in a direction orthogonal to the axis m, which is slightly larger than the intermediate shaft portion 41. This allows the pin 37 to be displaced in the radial direction with respect to the case 38. It cannot be rotated around.

Further, between the base member 43 and the holding member 44, the size of the space in which the head 40 is housed is larger than the size of the head 40 of the pin 37, and the head 40 of the pin 37 is axial and radial. It is installed with a slight clearance. Accordingly, the pin 37 can freely move in the radial direction and the axial direction between the base member 43 and the holding member 44 by the amount of the clearance, and can tilt in any direction with respect to the case 38. You can Accordingly, when the face plate 30 contacts the work 90, the orientation of the end face of the work 90 (the small end face 79 of the inner ring 82 in this embodiment) and the orientation of the contact face 36 of the face plate 30 are inclined with respect to each other. Even if there is, the abutting portion 22 can automatically tilt in any direction following the small end surface 79 of the workpiece 90 (it can be tilted), so that the small end surface 79 and the face plate 30 contact each other evenly over the entire circumference. be able to. Further, since the end surface of the head portion 40 of the pin 37 is spherical and is in contact with the case 38 at one point, the axial load acting on the face plate 30 is reliably supported even when the pin 37 is tilted. can do.
The diameter of the head portion 40 is larger than that of the through hole 46, and prevents the pin 37 from falling off the case 38.

Next, the support bearing 32 will be described.
The support bearing 32 is composed of one radial bearing 47 and a pair of thrust bearings 48 and 49 arranged on both sides of the radial bearing 47 in the axial direction. The outer ring of the radial bearing 47 is fixed to the support arm 21. The inner ring of the radial bearing 47 is inserted through the outer periphery of the screw shaft 45 provided on the base member 43, and is fixed integrally with the case 38 by screwing a nut on the shaft end of the screw shaft 45.
The radial bearing 47 is a roller bearing, and the cylindrical inner ring can be displaced in the axial direction with respect to the outer ring. When the contact portion 22 is pressed against the work 90 and a load in the axial direction is applied, the load is supported by the thrust bearing 48 on the other side in the axial direction. The thrust bearing 49 on one axial side prevents the inner ring from slipping out on the other axial side. The bearing rings of the thrust bearings 48 and 49 on the radial bearing 47 side are integrated with the outer ring of the radial bearing 47.

  Thus, in the turning apparatus 10 of the present embodiment, when the work 90 is processed, it can be urged coaxially in the axial direction. As a result, the work 90 can be pressed against the magnet chuck 12, so that the work 90 can be held with a remarkably large force as compared with the case where the work is held only by the magnet chuck 12.

  At the time of processing, since sliding friction occurs between the work 90 and the face plate 30, the face plate 30 rotates together with the work 90. Further, the case 38 rotates together with the face plate 30 because the through hole 46 is fitted in the intermediate shaft portion 41 of the pin 37 in a relatively non-rotatable manner in the circumferential direction and is supported by the support bearing 32. In this way, the face plate 30 smoothly rotates together with the work 90 and can be displaced in the radial direction by the centering mechanism 31, so that the rotation of the work 90 is not hindered. As a result, the work 90 can always be reliably held by the magnet chuck 12 and processed with high accuracy.

  Further, the contact portion 22 can be retracted from the work 90 in the radial direction by rotating the rotary shaft 23. As a result, a space for retracting the contact portion 22 in the axial direction is not required, so that the axial dimension of the clamp device 20 can be made compact. Therefore, even in a facility such as a machining center that has a small space in the axial direction, the turning apparatus 10 of the present embodiment can be easily incorporated.

Next, the procedure of a turning method for processing the workpiece 90 using the turning apparatus 10 will be described with reference to FIGS. 1 and 3.
As a machining procedure, each process of a workpiece preparation step, a workpiece fixing step, an outer periphery machining step, and an inner periphery machining step is sequentially performed.

In the work preparation step, after the annular inner ring processing material is manufactured by plastic working such as forging, the work 90 to be processed by the turning apparatus 10 is formed using a lathe or the like. The surface to be processed of the work 90 is larger than the final finished shape of the inner ring 82, and has a machining allowance.
After that, the work 90 is subjected to heat treatment such as quenching and tempering, and is hardened to a hardness of about 60 HRC.

  In the work fixing step, the work 90 subjected to the heat treatment in the work preparing step is fixed to the work mounting surface 13 of the magnet chuck 12 via the steel backing plate 14 (see FIG. 1). The work 90 is fixed such that the large end surface 78 is in contact with the backing plate 14 and its axis is in the axial direction. At this time, the accuracy of the position when the work 90 is mounted may be such that the machining allowance can be machined in the subsequent steps (outer peripheral machining step, inner peripheral machining step), and the center line of the workpiece 90 and the spindle 11 are not necessarily required. The axis m of does not have to match exactly.

Next, the outer peripheral processing step will be described.
In the outer peripheral processing step, the outer peripheral surface of the work 90 is turned while the workpiece 90 is axially biased by the clamp device 20. The outer peripheral surface means the whole or a part of the surface cut from the outside in the radial direction, such as the inner raceway surface 85, the outer peripheral surface of the large collar 87, the guide surface 88 of the tapered roller, and the outer peripheral surface of the small collar 86. Hereinafter, the surface processed in the outer peripheral processing step will be described as “outer peripheral surface A”.

In the outer periphery processing step, the rotation shaft 23 of the clamp device 20 rotates, and the contact portion 22 moves to a position coaxial with the main shaft 11 (position A in FIG. 3). Then, the swing support base 24 moves to the other side in the axial direction. At this time, the reference hole 25 provided in the support arm 21 and the positioning pin 16 are fitted to each other, the circumferential position of the contact portion 22 becomes coaxial with the main shaft 11, and the face plate 30 of the contact portion 22 is connected to the work 90. Abut in the axial direction. Note that FIG. 1 shows a state before the face plate 30 and the workpiece 90 are brought into contact with each other.
In the present embodiment, the face plate 30 is supported by the centering mechanism 31, so that the contact surface 36 of the attachment 33 automatically changes its direction so as to contact the entire surface of the work 90 following the small end surface 79. You can Therefore, the end surface of the work 90 can be pressed with a uniform force over the entire circumference.
The face plate 30 does not necessarily have to contact the work 90 over the entire circumference. For example, a plurality of radial grooves for discharging foreign matter may be formed on the contact surface 36 so as to make intermittent contact in the circumferential direction. However, like the conventional clamp claw, when locally clamped, the work 90 deforms into a polygon. Therefore, the length in the circumferential direction of contact is preferably about ⅔ or more of the entire length of the work 90.

  In this way, the outer peripheral surface A is cut while the workpiece 90 is axially biased toward the magnet chuck 12 by the contact portion 22. As described above, by using the clamping method of pressing the work 90 in the axial direction, a large sliding frictional force is generated between the work 90 and the magnet chuck 12, so that the work 90 is held more than the case where it is held only by the magnetic force. It can be fixed more firmly. Therefore, in the turning apparatus 10 of the present embodiment, the outer peripheral surface A of the work 90 can be processed by the hard skiving method having a large cutting resistance, and the outer peripheral surface A can be processed with a good surface roughness. Can be formed on the surface. Further, in the hard skiving method, the processing speed can be increased and the life of the chip is extended, so that the processing cost can be reduced.

In this way, the outer peripheral surface A of the work 90 is machined into a cylindrical surface coaxial with the axis m.
Further, in the method of holding the work 90 as in the present embodiment, the work 90 is merely sandwiched in the axial direction by the contact portion 22 and the magnet chuck 12, and is not subjected to a force in the radial direction. For this reason, the work 90 is processed without any distortion in the radial direction. Therefore, the roundness of the outer peripheral surface A can be reduced even when the turning processing device 10 is removed after the end of processing.

Next, the inner circumference processing step will be described.
In the inner peripheral machining step, the inner peripheral surface is machined by cutting while the contact portion 22 is retracted from the work 90 and is arranged at the position shown by B in FIG. The inner peripheral surface refers to the whole or a part of the inner peripheral surface 72 of the inner ring 82 and other surfaces cut from the inside in the radial direction. Hereinafter, the surface processed in the inner peripheral processing step will be described as “inner peripheral surface B”.
When retracting the contact portion 22, first, the swing support base 24 is moved to one side in the axial direction so that the face plate 30 is retracted in the axial direction from the work 90, and thereafter, the rotary shaft 23 is rotated. The contact portion 22 moves to a position retracted from the work 90 in the radial direction.

  The work 90 is fixed to the main shaft 11 by the magnetic force of the magnet chuck 12, and rotates together with the main shaft 11. In the inner circumference processing step, the contact portion 22 is retracted from the work 90, and the inner circumference of the work 90 is open toward the one side in the axial direction. The inner peripheral surface B of can be easily processed. Since the cutting resistance is not large when the inner peripheral surface B is processed, it can be fixed by the magnet chuck 12.

Thus, in the inner peripheral processing step, the inner peripheral surface B is processed into a cylindrical surface coaxial with the axis m.
At this time, the workpiece 90 is still fixed to the magnet chuck 12 in the outer periphery processing step, and is not removed from the turning device 10 even after the outer periphery processing step is completed. Therefore, when the inner peripheral surface B is machined in the inner peripheral machining step, the outer peripheral surface A of the work 90 is attached coaxially with the axis m, and therefore the work 90 is machined by machining the inner peripheral surface B in this state. The inner peripheral surface B can be machined completely coaxially with the outer peripheral surface A.

  Further, in the inner circumference processing step, the work 90 is only adsorbed in the axial direction by the magnet chuck 12 and is not subjected to a force in the radial direction. Therefore, the work 90 is machined in a state where there is no distortion in the radial direction, and at the end of machining, the work 90 is not elastically deformed, and is removed from the turning apparatus 10 in the shape machined into a perfect circle. ..

  Thus, in the present embodiment, the inner peripheral surface B and the outer peripheral surface A of the work 90 can be machined completely coaxially, and the circularity of the outer peripheral surface A and the inner peripheral surface B can be reduced. Further, since the work 90 can be clamped more firmly than the method of attracting with magnetic force or air, the hard skiving method can be used when processing the outer peripheral surface A. Thereby, the accuracy of the finished surface of the work 90 can be further improved.

Although the embodiments of the present invention have been described above, the matters described here are merely examples, and various modifications can be made without departing from the spirit of the invention.
For example, in the present embodiment, the case where it is used as a turning unit of a machining center has been described, but it may be used for processing by a general lathe.
Further, although the case where the inner ring 82 is machined has been described in the present embodiment, the inner and outer peripheries of the outer ring 81 and other annular work 90 can be machined coaxially with high precision in the same manner.

(Embodiment) 10: Turning device, 11: Spindle, 12: Magnet chuck (first holding part), 13: Work mounting surface, 14: Backing plate, 15: Pedestal, 16: Positioning pin, 20: Clamp device , 21: support arm, 22: abutting part, 23: rotating shaft, 24: rocking support base (second holding part), 25: reference hole, 30: face plate, 31: centering mechanism, 32: support bearing, 33: Attachment, 34: Face plate base, 36: Contact surface, 37: Pin, 47: Radial bearing, 48, 49: Thrust bearing,
(Tapered roller bearing) 71: outer peripheral surface (outer ring), 72: inner peripheral surface (inner ring), 80: tapered roller bearing, 81: outer ring, 82: inner ring, 84: outer raceway surface, 85: inner raceway surface,
(Prior Art) 90: Workpiece, 91: Clamper, 94: Collet Chuck

Claims (5)

A turning device for processing an annular work by cutting,
A spindle that rotates about an axis,
With the axial direction as the axial direction,
A first holding portion which is installed at an end portion of the spindle on one axial side and holds the work substantially coaxially with the spindle;
An abutting portion arranged on one axial side of the work and abutting the work in the axial direction,
A second holding portion that holds the abutting portion so as to advance and retreat in the axial direction toward the workpiece,
The contact portion, when processing the outer peripheral surface of the work, abuts against the work and biases the work toward the other side in the axial direction, and when processing the inner peripheral surface of the work, A turning apparatus, wherein the first holding part retracts from the work while holding the work. The abutting portion has a face plate that comes into axial contact with the work, and the face plate is rotatable with the work and tiltable in any direction following the work. The turning device according to claim 1. The face plate is supported so as to be rotatable around a rotary shaft provided in parallel with the main shaft at a position distant from the main shaft in the radial direction, and is retracted from the work in the radial direction. The turning device according to claim 2. The turning apparatus according to any one of claims 1 to 3, wherein the outer periphery of the work is processed by a hard skiving method. A turning method for processing an annular work by cutting,
A spindle that rotates about an axis,
With the axial direction as the axial direction, a first holding unit that is installed at an end of the main shaft on the one axial side and that holds the workpiece substantially coaxially with the main shaft,
An abutting portion arranged on one axial side of the work and abutting the work in the axial direction,
And a second holding portion that holds the abutting portion so as to advance and retract in the axial direction toward the workpiece,
A work fixing step of fixing the work to the first holding portion,
An outer periphery processing step of processing the outer periphery of the work in a state where the contact portion is in contact with the work and urges the work toward the other side in the axial direction,
An inner circumference processing step of processing the inner circumference of the work by retracting the contact portion from the work while the first holding part holds the work.
A turning method characterized by having.