JP3969292B2 - Wheel holding mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a grindstone holding mechanism for holding a grindstone used for superfinishing or the like.
[0002]
[Prior art]
Superfinishing machines that perform superfinishing work, for example, a grindstone pressed against the raceway surface formed on the outer periphery of the inner ring of the ball bearing from the outside in the radial direction, with the rocking axis passing through the center of curvature of the raceway surface as the center. , And is configured to swing on a plane passing through the center of curvature and the center of rotation of the inner ring. In such a superfinishing machine, the grindstone is inserted into a through-hole provided in the grindstone adapter with its both ends projecting outward, and another is applied by a pressure cylinder or the like disposed on the one end side. It is comprised so that an edge part may be pressed on a track surface (for example, refer patent document 1).
[0003]
[Patent Document 1]
Japanese Patent Publication No. 4-24186 (Fig. 2)
[0004]
[Problems to be solved by the invention]
By the way, in order to stabilize the processing accuracy with respect to a workpiece such as an inner ring, the grindstone needs to be held by the adapter in a state where a gap with respect to the grindstone adapter is appropriately maintained. In other words, the grindstone adapter is required to hold the grindstone in a state in which the pressing force in the pressing direction against the raceway surface of the grindstone by the cylinder is prevented and the wobble is prevented from wobbling. Such stable grinding wheel holding prevents the work processing accuracy from being lowered. Specifically, the grindstone adapter is required to hold the grindstone with a gap of about 0.01 to 0.1 mm as an appropriate gap between the wall surface of the through hole and the surface of the grindstone.
[0005]
However, in the conventional grindstone holding mechanism as described above, the grindstone wears over time on the wall surface of the through-hole due to the contact between the grindstone and the wall surface of the through-hole of the grindstone adapter. It becomes impossible to hold the grindstone with the appropriate gap. As a result, the grindstone fluctuates greatly and the workpiece machining accuracy decreases. In addition, since the gap is a minute gap as described above, there is also a problem that the machining accuracy of the workpiece is easily affected by variations in the radial direction dimension of the grindstone.
Depending on the degree of wear of the grindstone adapter, the grindstone may be removed depending on the degree of wear of the grindstone adapter when removing the grindstone adapter from the finished workpiece or when removing the workpiece or setting the next workpiece on the superfinishing machine. Occasionally, the adapter could slip out and processing could not be performed stably and continuously.
[0006]
In view of the conventional problems as described above, the present invention maintains an appropriate gap between the grindstone and the through hole of the grindstone adapter during processing even when wear occurs on the wall surface of the through hole of the grindstone adapter. The objective is to provide a grindstone holding mechanism that can prevent a decrease in the machining accuracy of the workpiece and reliably prevent the grindstone from slipping out of the grindstone adapter during non-machining and can perform continuous workpiece machining stably. And
[0007]
[Means for Solving the Problems]
The present invention is a grindstone holding mechanism that performs grinding on the processed surface by being swung in a state of being pressed against the processed surface,
A grindstone adapter provided with a through-hole into which the grindstone is inserted with a gap, a movable part that can be brought into and out of contact with the grindstone within the through-hole, and the movable part in contact with the grindstone Moving means for separating, and control means for performing drive control of the moving means,
The control means moves the movable part away from the grindstone so that a gap between the grindstone and the through hole becomes a predetermined gap during processing, and brings the movable part into contact with the grindstone during non-processing. A grindstone is fixed to the grindstone adapter (Claim 1).
[0008]
In the grindstone holding mechanism configured as described above, the control means controls the movement of the moving means, so that the movable part is moved so that the gap between the grindstone and the through hole of the grindstone adapter becomes a predetermined gap during processing. Even if wear occurs on the wall surface of the through hole, the gap can be maintained at an appropriate gap by moving the movable part according to the wear size. Moreover, since the said grindstone can be fixed to a grindstone adapter by making a movable part contact a grindstone at the time of non-processing, it can prevent reliably that a grindstone slips out from an adapter.
[0009]
In the grindstone holding mechanism (Claim 1), it is preferable that the moving means is configured using a piezo element (Claim 2).
In this case, the size (volume) of the piezo element is changed by the applied voltage and the movable part can be moved, and the structure of the moving means can be simplified.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment showing a grindstone holding mechanism of the present invention will be described with reference to the drawings. In the following description, a case where the present invention is applied to a superfinishing machine that superfinishes the raceway surface of the inner ring of the ball bearing by grinding will be described.
FIG. 1 is a schematic cross-sectional view showing a main part of a grindstone holding mechanism according to an embodiment of the present invention. In the figure, a grindstone holding mechanism 1 of this embodiment includes a grindstone adapter 2 that holds a columnar (for example, columnar) grindstone A, and this holding mechanism 1 is a grindstone head portion (not shown) of the superfinishing machine. ). The grindstone holding mechanism 1 is disposed between an inner ring 10 as a workpiece (workpiece) and a grindstone pressing mechanism 20 that presses the grindstone A against the inner ring 10 side during grinding. In the state where the grindstone A pressed against the raceway surface 10 a of the inner ring 10 is held by 20, it is configured to swing together with the mechanism 20 in the left-right direction (direction indicated by a double arrow B) in the figure. Further, the grindstone holding mechanism 1 is configured to be movable above the raceway surface 10a, and can be retracted from the machining position shown in the drawing when not being machined.
The inner ring 10 is supported by a support device (not shown) and is rotated in the circumferential direction during the processing.
[0011]
The grindstone pressing mechanism 20 is provided with a cylinder 20a and a piston rod 20b whose one end is disposed in the cylinder 20a and whose other end is in contact with the grindstone A. A pressurized fluid such as air or oil is supplied or discharged into a pressure chamber 20c formed in 20a. Then, the grindstone pressing mechanism 20 adjusts the pressure applied to the grindstone A pressed against the raceway surface 10a by sliding the rod 20b downward in the figure based on the supply amount of the pressurized fluid to the pressure chamber 20c. To do. Further, the grindstone A is swung in the direction of the double arrow B from the position shown in the drawing together with the holding mechanism 1 in a state where the grindstone pressing mechanism 20 applies pressure to the grindstone A, so that the grindstone A has the center of curvature of the raceway surface 10a. It vibrates left and right on the raceway surface 10a around the swing axis passing therethrough, and the raceway surface 10a is superfinished.
[0012]
The grindstone adapter 2 includes an adapter main body 2a and a cylindrical sleeve member 2b that is fitted into a fitting hole 2a1 provided in the adapter main body 2a and that is configured as a through hole 2b1 into which the grindstone A is inserted. The right end of the figure is connected to the swing mechanism on the main body side of the superfinishing machine.
The sleeve member 2b is provided with an opening 2b2 having a rectangular cross section. The opening 2b2 is formed according to the opening shape and is flush with the wall surface of the through hole 2b1. A movable portion 2c (shown by a cross hatch in the figure) having a rectangular cross section is attached to be removable.
[0013]
Further, on one side of the movable portion 2c (the back surface of the opposite surface of the grindstone A), a driving unit 3 is connected as a moving means for moving the portion 2c to and away from the grindstone A. The movable portion 2c is It is configured to be able to contact and separate from the grindstone A inside the hole 2b1 in an orthogonal direction orthogonal to the axis of the through hole 2b1. And this movable part 2c is separated from the grindstone A so that the clearance gap between the surface of the grindstone A and the wall surface of the through-hole 2b1 may be a minute predetermined gap at the time of grinding. Further, when the grindstone adapter 2 holds the grindstone A with a predetermined gap between the grindstone A and the through hole 2b1 in this way, the pressure applied to the adapter 2 in the pressing direction of the grindstone A from the rod 20b varies. The whetstone A can be stably held in a state in which the whetstone A is prevented from wobbling.
In addition, the movable portion 2c is moved to the center side of the through hole 2b1 when not being processed, and comes into contact with the grindstone A so as to sandwich the grindstone A with the wall surface of the through hole 2b1. Fix to the grindstone adapter 2.
[0014]
The drive unit 3 is installed in a mounting hole 2a2 provided in the adapter main body 2a so that one end opening communicates with the fitting hole 2a1. The drive unit 3 includes a piezo (piezoelectric) element disposed so as to be able to expand or contract in a direction orthogonal to the through-hole 2b1. The movable portion 2c is linearly slightly displaced by deforming the piezo element in accordance with the input instruction signal (voltage signal).
[0015]
The control unit 5 includes a first adjusting means 5a for adjusting a voltage value for clamping for bringing the movable part 2c into contact with the grindstone A and fixing it to the adapter 2, and a contact state between the grindstone A of the movable part 2c. And a second adjusting means 5b for adjusting the voltage value for unclamping for making the gap of the grindstone A with respect to the adapter 2 a predetermined gap is provided. The control unit 5 includes an amplifier 5c that amplifies the voltage of a power source (not shown) based on the voltage value instructed by the first adjusting means 5a or the second adjusting means 5b. The voltage applied to the piezo element of the drive unit 3 is continuously changed according to the adjustment value in the first adjustment means 5a or the second adjustment means 5b, and fine adjustment of the displacement amount in the movable part 2c is smoothly performed. Can be done.
[0016]
As described above, in the grindstone holding mechanism 1 of the present embodiment, the movable portion 2c is separated from the grindstone A so that the gap between the grindstone A and the through hole 2b1 of the grindstone adapter 2 becomes a predetermined gap during grinding. The said clearance gap can be maintained with a suitable clearance gap at the time of grinding. That is, even when wear occurs on the wall surface of the through hole 2b1 or when a new grindstone A is set on the grindstone adapter 2, the first adjusting means 5a and the second adjusting means 5b appropriately piezo the drive unit 3. By adjusting the voltage applied to the element and slightly moving the movable part 2c in accordance with the wear dimension and the new outer dimension of the grindstone A, the gap can be easily maintained at an appropriate gap. As a result, even when the wall surface of the through-hole 2b1 is worn, the grindstone adapter 2 can hold the grindstone A with an appropriate gap and can prevent the processing accuracy of the inner ring 10 from being lowered. Moreover, since the movable part 2c can contact the grindstone A so that the grindstone A is held between the wall surfaces of the through holes 2b1 when not being machined, and the grindstone A can be fixed to the grindstone adapter 2, the inner ring after the machining is completed. It is possible to reliably prevent the grindstone A from coming out of the through hole 2b1 when taking out 10 or setting the next inner ring 10 on the superfinishing machine. Accordingly, continuous machining of the inner ring 10 can be performed stably.
[0017]
Moreover, in this embodiment, it is possible to reliably prevent the grindstone A from coming out of the grindstone adapter 2 regardless of whether the grindstone adapter 2 is worn or not by bringing the movable part 2c into contact with the grindstone A. It is not necessary to connect the grindstone A and the piston rod 20b integrally using a connecting member such as a bolt screwed to the grindstone end or a chuck component that holds the end, and the grindstone A can be replaced. Can be performed smoothly.
[0018]
In the above description, the case where the present invention is applied to a grindstone holding mechanism incorporated in a superfinishing machine for an inner ring raceway surface has been described. However, the present invention holds a grindstone that is swung in a state of being pressed against a machining surface. It can be applied, and can be applied to various machine tools that perform grinding such as finishing on the processed surface.
In the above description, the grindstone adapter 2 provided with the movable portion 2c in the sleeve member 2b having the through hole 2b1 has been described, but the present invention is not limited thereto, and the through hole into which the grindstone is inserted; What is necessary is just to provide a movable part that can be brought into and out of contact with the grindstone inside the through hole. It is not limited. Specifically, a plurality of movable parts equally distributed around the grindstone may be provided, and the movable parts may be moved to adjust the gap with the grindstone adapter or to lock the grindstone. Further, a configuration may be adopted in which a gap is adjusted or the grindstone is automatically locked by providing a detection means for detecting the dimension of the gap and performing a feedback control based on the gap detection value of the detection means.
[0019]
Further, in the above description, the case where the driving unit (moving unit) 3 is configured using a piezo element has been described. However, the moving unit of the present invention can move the movable part 2c toward and away from the grindstone A. A micromotor, an electromagnet, or the like can be used instead of the piezo element. However, when these motors and electromagnets are used, it is necessary to provide a conversion member that converts the rotational motion of the motor into a linear motion, or to secure a larger installation space for the electromagnet than the piezoelectric element. Therefore, it is preferable to use a piezo element that facilitates the simplification of the structure of the drive unit 3 and that can easily make the grindstone adapter 2 and thus the grindstone holding mechanism 1 compact.
In the above description, the control unit 5 including the two adjustment units 5a and 5b has been described. However, for example, only the adjustment unit that adjusts the voltage value for clamping is provided in the control unit, and the voltage value for unclamping is You may comprise so that it may apply automatically by the circuit which makes only a predetermined voltage value lower than the voltage value for clamping.
Further, two piezo elements are arranged in two layers in the moving direction of the movable portion 2c, and one and the other are used as the moving means and the pressure sensor, respectively, and the applied voltage of the piezo element for the moving means based on the sensor detection value. You may comprise so that it may adjust.
[0020]
【The invention's effect】
The present invention configured as described above has the following effects.
According to the grindstone holding mechanism of the first aspect, even when wear occurs on the wall surface of the through-hole or when a new grindstone is set on the grindstone adapter, the movable part is slightly changed according to the wear dimension and the new external dimension of the grindstone. By displacing, the gap can be maintained at an appropriate gap, and unlike the conventional example, wobbling of the grindstone caused by the widening of the gap can be reliably and easily prevented, and the workpiece machining accuracy is reduced. Can be prevented. In addition, since it is possible to reliably prevent the grindstone from coming out of the grindstone adapter during non-machining, continuous machining of the workpiece can be performed stably.
[0021]
Moreover, according to the grindstone holding mechanism of claim 2, since the structure of the moving means can be simplified, the grindstone adapter and the grindstone holding mechanism can be easily made compact, and it is small and excellent in processing efficiency. A grindstone holding mechanism can be configured easily.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a main part of a grindstone holding mechanism according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Grindstone holding mechanism 2 Grindstone adapter 2a Adapter main body 2b Sleeve member 2b1 Through hole 2c Movable part 3 Drive part (moving means, piezo element)
5 Control unit (control means)
10 Inner ring (Raceway)
10a Raceway A Grinding wheel

Claims (2)

A whetstone holding mechanism that grinds the processed surface by being rocked while being pressed against the processed surface,
A grindstone adapter provided with a through-hole into which the grindstone is inserted with a gap, and a movable part that can be brought into and out of contact with the grindstone inside the through-hole,
Moving means for moving the movable part toward and away from the grindstone;
Control means for performing drive control of the moving means,
The control means moves the movable part away from the grindstone so that a gap between the grindstone and the through hole becomes a predetermined gap during processing, and brings the movable part into contact with the grindstone during non-processing. A grindstone holding mechanism for fixing a grindstone to the grindstone adapter. The grindstone holding mechanism according to claim 1, wherein the moving means is configured using a piezo element.

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