Shoe support grinder and processing method of workpiece

Abstract

To provide a shoe support grinder which improves roundness and productivity of a thin workpiece W.SOLUTION: A processing method of workpiece includes a process of performing rough machining of a workpiece W by means of a grindstone 3 on a front shoe 11 and a rear shoe 12 of a shoe support grinder 1, a process of rotating an unloading arm 16 thereafter, rotating the rough-machined workpiece W by rotating the unloading arm to a place of a demagnetizing device 20 to decrease or remove magnetism of the workpiece W, and a process of rotating the unloading arm 16 again to load the workpiece W onto the front shoe 11 and the rear shoe 12 to perform finish processing by means of the grindstone 3.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a shoe support grinding machine equipped with a magnetic chuck and a method for machining a workpiece.

Background Art

[0002] Conventionally, as this type of grinding machine, a bearing groove grinding machine as described in JIS B 0105 2102 number 06907 is known.

[0003] And, for example, as in Patent Document 1, a grinding machine equipped with a front shoe, a rear shoe, a magnetic chuck, a loading arm, an unloading arm, etc. is known.

[0004] This type of grinding machine has been widely used since the 1980s as described in Non-Patent Document 1.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in a conventional shoe support grinding machine, when machining a thin workpiece such as an inner ring of a bearing, due to the flatness shape of the end face as a machining reference (for example, a shape with minute unevenness), the workpiece is deformed under the influence of the chucking force of the magnetic chuck. As a result, there is a problem that the roundness after machining removed from the magnetic chuck becomes triangular or elliptical. In order to minimize such influence, it is necessary to machine with a weakened chucking force, which lengthens the machining time.

[0007] For this reason, rough machining is performed with the chucking force increased, demagnetization is carried out, and finish machining is then performed after weakening the chucking force.

[0008] Conventionally, after unloading the roughly finished workpiece, demagnetization was carried out, and management in two steps (two machines or two passes) was required.

[0009] The present invention has been made in view of such points, and its object is to solve such conventional problems and improve the roundness and productivity of thin workpieces.

Means for Solving the Problems

[0010] In order to achieve the above object, in this invention, a devise is added to the procedure for demagnetizing the workpiece.

[0011] Specifically, in the first invention, a front shoe and a rear shoe that support a magnetic workpiece to be ground on a grindstone, a magnetic chuck provided on a main spindle and gripping the workpiece, a rotatable loading arm for placing the workpiece on the front shoe and the rear shoe, a rotatable unloading arm for unloading the workpiece from above the front shoe and the rear shoe, a first drive unit for rotationally driving the loading arm, a second drive unit for rotationally driving the unloading arm, A demagnetizing device for reducing or removing the magnetism of the workpiece, A control device that controls the first drive unit and the second drive unit to control the timing of the rotation operations of the loading arm and the unloading arm, After the workpiece is roughly machined by the grinding wheel on the front shoe and the rear shoe, the control device operates the second drive unit, rotates the unloading arm to rotate the workpiece to the demagnetizing device, reduces or removes the magnetism of the workpiece, and rotates the unloading arm again to place the workpiece on the front shoe and the rear shoe and perform finish machining by the grinding wheel.

[0012] According to the above configuration, since the workpiece is firmly gripped by the magnetic chuck and the cutting amount is increased for rough machining, in the case of a thin workpiece, the roundness is likely to be low due to the influence of the magnetic force. However, the control device rotates only the unloading arm once to demagnetize the workpiece with the demagnetizing device and then returns it to the grinding position. Therefore, in the finishing process, the gripping force of the magnetic chuck can be reduced, and finish machining can be performed while maintaining the roundness. In this way, demagnetization can be easily performed between rough machining and finish machining with one machine.

[0013] In the second invention, in the first invention, The first drive unit and the second drive unit are servo motors that can be separately rotationally controlled by the control device.

[0014] According to the above configuration, since the first drive unit and the second drive unit can be rotated by separate servo motors, the workpiece can be easily demagnetized between rough machining and finish machining without interference between the loading arm and the unloading arm.

[0015] In the invention of the third workpiece processing method, A front shoe and a rear shoe that support a magnetic workpiece to be ground by a grinding wheel, A magnetic chuck provided on the main spindle and gripping the workpiece, A rotatable loading arm for placing the workpiece on the front shoe and the rear shoe, A rotatable unloading arm for unloading the workpiece from above the front shoe and the rear shoe, A first drive unit for rotationally driving the loading arm, A second drive unit for rotationally driving the unloading arm, Prepare a shoe support grinding machine equipped with a demagnetizing device for reducing or removing the magnetism of the workpiece, Rough-machine the workpiece on the front shoe and the rear shoe, Operate the second drive unit, rotate the unloading arm to rotate the rough-machined workpiece to the demagnetizing device, and reduce or remove the magnetism of the workpiece, Rotate the unloading arm to place the workpiece on the front shoe and the rear shoe again and finish-machine it with the grinding wheel.

[0016] According to the above configuration, since rough machining is performed with a large cutting amount while firmly gripping the workpiece with a magnetic chuck, the roundness is likely to be low in a thin-walled workpiece. However, once only the unloading arm is rotated to demagnetize the workpiece with a demagnetizing device and then returned to the grinding position, in the finishing process, the gripping force of the magnetic chuck can be reduced, and finishing can be performed while maintaining the roundness. In this way, demagnetization can be easily performed between rough machining and finishing with one machine.

Advantages of the Invention

[0017] As described above, according to the present invention, it is possible to demagnetize the workpiece during the processing cycle between rough finishing and finishing, the chucking force during rough finishing can be freely switched, and it can contribute to improving the roundness of thin-walled workpieces and significantly improving productivity.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0020] -Configuration of the Shoe Support Grinding Machine- Figs. 1 to 3 show the shoe support grinding machine 1 according to an embodiment of the present invention. This shoe support grinding machine 1 includes a base 2 installed on the ground or the like, and a grinding wheel shaft 4 for rotatably supporting a grinding wheel 3 is provided on this base 2.

[0021] The grinding wheel shaft 4 is placed on an X-axis table 5 and a Z-axis table 6 and is movable in the X-axis direction and the Z-axis direction respectively, and is rotatable at a specified speed by a tool motor 4a.

[0022] And at a position facing the grinding wheel shaft 4, a main spindle 7 for rotatably supporting a workpiece W in parallel with this grinding wheel shaft 4 is provided. The main spindle 7 is rotatable by a main spindle motor 8, and a magnetic chuck 10 controlled to be magnetized or demagnetized by a control device 9 is provided at its tip.

[0023] As shown enlarged in Fig. 4, at a position facing the magnetic chuck 10, a front shoe 11 and a rear shoe 12 for supporting a magnetic workpiece W to be ground by the grinding wheel 3 are provided. These front shoe 11 and rear shoe 12 themselves may be known ones.

[0024] And a loading arm 15 for placing the workpiece W on the front shoe 11 and the rear shoe 12 is rotatably provided near these front shoe 11 and rear shoe 12, specifically, at a position slightly away from the grindstone 3 than the rear shoe 12.

[0025] An unloading arm 16 for unloading the workpiece W from above the front shoe 11 and the rear shoe 12 is rotatably provided at a lower position closer to the grindstone 3 than this loading arm 15 (between the loading arm 15 and the rear shoe 12).

[0026] The loading arm 15 is rotationally driven by a first servo motor 19a as a first drive unit. Further, the unloading arm 16 is rotationally driven independently of the loading arm 15 by a second servo motor 19b as a second drive unit. Although not shown in detail, the loading arm 15 and the unloading arm 16 each have a loading plug and are configured to advance in the Z-axis direction when gripping the workpiece W and to retract when releasing the workpiece W.

[0027] The shoe support grinding machine 1 further includes a control device 9 that controls the first servo motor 19a and the second servo motor 19b to control the timing of the rotational operations of the loading arm 15 and the unloading arm 16. The control device 9 is composed of, for example, an electric control panel equipped with a microcomputer or the like.

[0028] Although details will be described later, the control device 9 operates the first servo motor 19a after the workpiece W is rough machined on the front shoe 11 and the rear shoe 12, rotates the unloading arm 16 to rotate the workpiece W to the demagnetizing device 20, reduces or removes the magnetism of the workpiece W, and then places the workpiece W on the front shoe 11 and the rear shoe 12 again to perform control for finish machining with the grindstone 3.

[0029] The first servo motor 19a and the second servo motor 19b are servo motors that can be separately rotationally controlled by the control device 9, but they do not necessarily have to be configured as servo motors. Other electric actuators or air or hydraulic actuators may also be used.

[0030] In this embodiment, the loading arm 15 is longer than the unloading arm 16, and the loading arm 15 is rotatable between the work receiving position of the inshoot 17 where the work W is carried in and the grinding position composed of the front shoe 11 and the rear shoe 12.

[0031] The unloading arm 16 is rotatable between the grinding position composed of the front shoe 11 and the rear shoe 12 and the unloading position of the outshoot 18 where the processed work W is carried out.

[0032] In this embodiment, the loading arm 15 is slightly longer than the unloading arm 16, but the length relationship may be reversed.

[0033] And the demagnetization device 20 is provided at the unloading position of the outshoot 18. The demagnetization device 20 itself may be a known one.

[0034] In this embodiment, a dressing device 21 for dressing the grinding wheel 3 is provided on the side opposite to the grinding wheel shaft 4 of the grinding wheel 3.

[0035] -Processing method of workpiece W- Next, a processing method of the workpiece W using the shoe support grinding machine 1 according to this embodiment will be described with reference to FIG. 5. In this embodiment, the processing of the groove portion on the outer circumference of the inner ring of the bearing will be described as an example, but it is not limited thereto.

[0036] In the invention of the processing method of the workpiece W according to this embodiment, first, the above-described shoe support grinding machine 1 is prepared.

[0037] Then, in step S01, the workpiece W is roughly machined on the front shoe 11 and the rear shoe 12. In this embodiment, the groove portion on the outer periphery of the inner ring of the bearing is roughly machined. At this time, since the workpiece W is firmly gripped by the magnetic chuck and roughly machined with a relatively large force, in the case of a thin-walled workpiece W, due to the influence of the magnetic force, the roundness may be low when demagnetized.

[0038] After cutting a predetermined amount, in step S02, the rough machining is completed.

[0039] Next, in step S03, the X-axis table 5 is moved to retract the grinding wheel 3.

[0040] Next, in step S04, the rotation of the main spindle 7 is stopped.

[0041] In step S05, the magnetic chuck 10 is reversely magnetized to release the magnetic force of the workpiece W.

[0042] In step S06, the unloading arm 16 holding the workpiece W rotates the workpiece W and rotates it to the position of the demagnetizing device 20.

[0043] In step S07, the workpiece W is demagnetized by the demagnetizing device 20.

[0044] In step S08, the unloading arm 16 is rotated in the reverse direction to return the workpiece W to the grinding position above the front shoe 11 and the rear shoe 12 again.

[0045] In step S09, the magnetic chuck 10 is magnetized again to grip the workpiece W. At this time, a magnetic force is applied to the workpiece W with a magnetic force weaker than that during rough machining. Then, the workpiece W does not deform as in the case of rough machining.

[0046] In step S10, the main spindle 7 is rotated again. The rotational speed shall be the rotational speed of the finish machining.

[0047] In step S11, while moving the X-axis table 5, the grinding wheel 3 is advanced to adjust the depth of cut.

[0048] In step S12, finish machining is performed with the grinding wheel 3. At this time, since the magnetic force by the magnetic chuck 10 is relatively weak, the workpiece W is finish-machined in a state where it hardly bends. During finish machining, since the depth of cut is relatively small and the rotational torque is also small, even if the magnetic force is weaker than during rough machining, the workpiece W does not come off the magnetic chuck 10.

[0049] Then, when the machining of a predetermined depth of cut is completed, in step S13, the finish machining is terminated.

[0050] Next, the same processes from the retraction of the grinding wheel in step S03 to the demagnetization of the workpiece in step S07 are performed from step S14 to step S18.

[0051] Then, in step S19, the control device 9 gives an instruction, rotates the first servo motor 19a and the second servo motor 19b to rotate the machined workpiece W to the unloading position of the outshoot 18, and at the same time, demagnetization is performed again by the demagnetizing device 20, and the loading arm 16 receives the next workpiece W from the workpiece receiving position of the inshoot 17 and conveys it to the grinding position.

[0052] In step S20, the workpiece W that has come to the grinding position is magnetized to the magnetic chuck 10. The magnetic force at this time is a relatively strong magnetic force for rough machining.

[0053] In step S21, the control device 9 gives an instruction, rotates the first servo motor 19a and the second servo motor 19b, the loading arm 16 returns to the workpiece receiving position of the inshoot 17, and the unloading arm 16 returns to the grinding position.

[0054] In step S22, the rotation of the main spindle 7 is started.

[0055] In step S23, the grinding wheel 3 advances, and the process returns to step S01 to start rough machining of a new workpiece W.

[0056] Thus, after rough machining is completed, only the unloading arm 16 is rotated to demagnetize the workpiece W with the demagnetizing device 20 and then return it to the grinding position again. Therefore, in the finishing process, the gripping force of the magnetic chuck 10 can be reduced, and finishing can be performed while maintaining the roundness. In this way, demagnetization can be easily performed between rough machining and finishing with a single machine.

[0057] In this embodiment, the workpiece W is the inner ring of a bearing, and the grinding wheel 3 is used to machine the groove portion on the outer periphery of the inner ring. However, particularly when the inner ring of the bearing is thin, it is easily deformed by the influence of the magnetic chuck 10. However, in this embodiment, since it is not necessary to weaken the chucking force for machining, the machining time does not increase, and it is possible to machine the inner ring of the bearing with high roundness.

[0058] Thus, since the first servo motor 19a and the second servo motor 19b can be separately rotationally driven by the control device 9, the loading arm 15 and the unloading arm 16 can demagnetize the workpiece W between rough machining and finishing without interfering with each other. Conventionally, there was no idea of adopting a configuration with an increase in the number of such parts, and there was no such need.

[0059] Therefore, according to the shoe support grinding machine 1 according to this embodiment, it is possible to demagnetize the workpiece W during the machining cycle, freely switch the chucking force during rough machining and finishing, and significantly improve the roundness and productivity of the thin-walled workpiece W.

[0060] (Other Embodiments) The present invention may be configured as follows with respect to the above embodiment.

[0061] That is, in the above-described embodiment, as an example of the control device 9, an example of an electric control panel having a microcomputer was described. However, the control device 9 may be physically configured in any manner as long as it controls the "shoe support grinding machine 1". For example, the control device 9 may utilize software (program) such as a programmable logic controller (PLC). Alternatively, the control device 9 may be realized by combining hardware (circuit components).

[0062] Note that the above embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses.

Explanation of Reference Numerals

[0063] 1 Shoe support grinding machine 2 Base 3 Grinding wheel 4 Grinding wheel shaft 4a Tool motor 5 X-axis table 6 Z-axis table 7 Spindle 8 Spindle motor 9 Control device 10 Magnetic chuck 11 Front shoe 12 Rear shoe 15 Loading arm 16 Unloading arm 17 Insert 18 Outshoot 19a First servo motor 19b Second servo motor 20 Demagnetizing device 21 Dressing device

Claims

1. a front shoe and a rear shoe for supporting a magnetic workpiece to be ground by a grinding wheel; A magnetic chuck is provided on a main spindle and holds the workpiece; A rotatable loading arm that places the workpiece on the front shoe and the rear shoe; a rotatable unloading arm for unloading the workpiece from above the front shoe and the rear shoe; a first drive unit that drives the loading arm to rotate; a second drive unit that drives the unloading arm to rotate; A demagnetizing device that reduces or removes the magnetism carried by the workpiece; a control device that controls the first drive unit and the second drive unit to control timing of the rotation operation of the loading arm and the unloading arm, The control device is configured to perform control such that, after the workpiece is roughly machined by the grindstone on the front shoe and the rear shoe, the second drive unit is actuated, the unloading arm is rotated to rotate the workpiece to the demagnetization device, the magnetism of the workpiece is reduced or removed, and the unloading arm is rotated again to place the workpiece on the front shoe and the rear shoe and finish machine the workpiece by the grindstone. A shoe support grinding machine characterized by:

2. The first drive unit and the second drive unit are servo motors whose rotation can be controlled separately by the control device.

2. The shoe support grinding machine according to claim 1 .

3. a front shoe and a rear shoe for supporting a magnetic workpiece to be ground by a grinding wheel; A magnetic chuck is provided on a main spindle and holds the workpiece; A rotatable loading arm that places the workpiece on the front shoe and the rear shoe; a rotatable unloading arm for unloading the workpiece from above the front shoe and the rear shoe; a first drive unit that rotates the loading arm; a second driving unit that rotates the unloading arm; a shoe support grinding machine having a demagnetizing device for reducing or removing magnetism carried by the workpiece; Rough machining the workpiece on the front shoe and the rear shoe; Activating the second drive unit to rotate the unloading arm and rotate the roughly machined workpiece to the demagnetization device, thereby reducing or removing magnetism from the workpiece; The unloading arm is rotated to place the workpiece on the front shoe and the rear shoe again, and the workpiece is finished by the grindstone.

1. A method for grinding a workpiece, comprising:

Images