JP2004174683A - Grindstone holding mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grindstone holding mechanism capable of preventing lowering of working precision of a work by maintaining a proper clearance between a grindstone and a through hole of a grindstone adapter in working even in the case when a wall surface of the through hole of the grindstone adapter is abrased and capable of stably carrying out continuous working of the work by certainly preventing falling of the grindstone out of the grindstone adapter at the time of non-working. <P>SOLUTION: The grindstone adapter 2 is provided with a sleeve member 2b on which the through hole 2b1 to insert a grindstone A into it is formed and a movable part 2c free to make contact with and to separate from the grindstone A inside the through hole 2b1. Thereafter, the movable part 2c is separated from the grindstone A so that the clearance between the grindstone A and the through hole 2b1 of the grindstone adapter 2 becomes a specified clearance as a control unit (control means) 5 carries out driving control of a driving part (moving means) 3 at the time of working and the grindstone A is fixed on the grindstone adapter 2 by making the movable part 2c contact with the grindstone A at the time of non-working. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a grindstone holding mechanism for holding a grindstone used for superfinishing and the like.
[0002]
[Prior art]
The super-finishing machine that performs super-finishing is, for example, a grindstone pressed against the raceway surface formed on the outer circumference of the inner ring of the ball bearing from the outside in the radial direction, with the swing axis passing through the center of curvature of the raceway surface as the center. It 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 super-finishing machine, the grinding wheel is inserted into a through-hole provided in the grinding wheel adapter with both ends protruding outward, and the grinding wheel is pressed by a pressure cylinder or the like disposed at one end thereof. The end is pressed against the raceway surface (for example, see 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 for a workpiece such as an inner ring, the above-mentioned grindstone needs to be held by the grindstone adapter with the gap maintained properly. In other words, the whetstone adapter is required to hold the whetstone in a state where the pressing force of the cylinder in the pressing direction of the whetstone against the raceway surface is prevented from fluctuating, and the whetstone is prevented from wobbling. Such stable holding of the grindstone prevents a decrease in work processing accuracy. More specifically, in the whetstone adapter, it is required that the whetstone be held at 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 whetstone.
[0005]
However, in the conventional grinding wheel holding mechanism as described above, due to the contact between the grinding wheel and the wall surface of the through-hole of the grinding wheel adapter, the wall surface of the through-hole causes abrasion with the grinding wheel over time. The whetstone cannot be held in the appropriate gap. As a result, the whetstone is largely displaced, and the processing accuracy of the work is reduced. Further, since the gap is a minute gap as described above, there has been a problem that the processing accuracy of the work is easily affected by variations in the radial dimension of the grindstone.
Also, depending on the degree of wear of the grindstone adapter, the grindstone may be removed during removal of the work by releasing the grindstone adapter from the finished work, or when setting the next work in a super finishing machine, etc. In some cases, the adapter could fall out of the adapter and the machining could not be performed stably and continuously.
[0006]
In view of the above-described conventional problems, the present invention maintains a proper gap between the grindstone and the through hole of the grindstone adapter at the time of machining even when wear occurs on the wall surface of the through hole of the grindstone adapter. The purpose of the present invention is to provide a whetstone holding mechanism that can prevent a decrease in the processing accuracy of a work and prevent the whetstone from slipping out of a whetstone adapter during non-working, thereby stably performing a continuous processing of a work. And
[0007]
[Means for Solving the Problems]
The present invention is a whetstone holding mechanism that performs a grinding process on the processing surface by being rocked while being pressed against the processing surface,
A whetstone adapter provided with a through-hole for inserting the whetstone with a gap, and a movable part capable of coming into contact with and separating from the whetstone inside the through-hole, and connecting the movable part to the whetstone Moving means for separating, and control means for controlling the driving of the moving means,
The control means separates the movable portion from the grindstone so that a gap between the grindstone and the through hole becomes a predetermined gap at the time of machining, and contacts the movable portion with the grindstone at the time of non-machining, thereby A grindstone is fixed to the grindstone adapter (claim 1).
[0008]
In the whetstone holding mechanism configured as described above, the control means controls the driving of the moving means, so that the movable part is moved so that the gap between the whetstone and the through hole of the whetstone adapter becomes a predetermined gap during processing. Even if abrasion occurs on the wall surface of the through-hole, the gap can be maintained at an appropriate gap by moving the movable portion according to the abrasion dimension. In addition, at the time of non-machining, the whetstone can be fixed to the whetstone adapter by bringing the movable part into contact with the whetstone, so that the whetstone can be reliably prevented from falling out of the adapter.
[0009]
In the above-mentioned whetstone 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 changes according to the applied voltage, so that the movable part can be moved, and the structure of the moving means can be simplified.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment showing a grinding wheel holding mechanism of the present invention will be described with reference to the drawings. In the following description, a case will be described in which the present invention is applied to a superfinishing machine for superfinishing the raceway surface of an inner ring of a ball bearing by grinding.
FIG. 1 is a schematic 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 the present embodiment includes a grindstone adapter 2 for holding a columnar (for example, columnar) grindstone A, and the holding mechanism 1 is a grindstone head (not shown) of the superfinishing machine. ). The grindstone holding mechanism 1 is disposed between an inner ring 10 as a workpiece (work) and a grindstone pressing mechanism 20 for pressing the grindstone A toward the inner ring 10 during grinding. In a state where the grindstone A pressed against the raceway surface 10a of the inner race 10 by the inner ring 20 is held, it is configured to swing together with the mechanism 20 in the left-right direction (the direction indicated by the double-headed arrow B) in the figure. The whetstone holding mechanism 1 is configured to be movable above the raceway surface 10a, so that it can be evacuated from the processing position shown in the drawing when not processing.
The inner ring 10 is supported by a support device (not shown), and is rotated in the circumferential direction during processing.
[0011]
The grinding wheel pressing mechanism 20 includes a cylinder 20a, a piston rod 20b having one end disposed inside the cylinder 20a and the other end abutting on the grinding stone A. The cylinder 20a is provided via a supply / discharge port (not shown). A pressurized fluid such as air or oil is supplied or discharged into a pressure chamber 20c formed in the inside 20a. The grindstone pressing mechanism 20 slides the rod 20b downward in the figure based on the supply amount of the pressurized fluid to the pressure chamber 20c to adjust the pressing force to the grindstone A pressed against the raceway surface 10a. I do. Further, the whetstone A is swung in the direction of the double-headed arrow B from the position shown in the figure together with the holding mechanism 1 in a state where the whetstone pressing mechanism 20 applies the pressing force to the whetstone A, so that the whetstone A moves the center of curvature of the raceway surface 10a. It vibrates left and right on the raceway surface 10a around the swinging axis passing therethrough, and performs superfinishing on the raceway surface 10a.
[0012]
The grindstone adapter 2 includes an adapter body 2a and a cylindrical sleeve member 2b which is fitted into a fitting hole 2a1 provided in the adapter body 2a and has a through hole 2b1 into which the grindstone A is inserted. The right end of the figure is connected to a 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 in accordance with the opening shape, and is configured to be 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 so as to be freely attached and detached.
[0013]
Further, a drive unit 3 as a moving means for moving the portion 2c toward and away from the grindstone A is connected to one surface of the movable portion 2c (the back surface opposite to the facing surface of the grindstone A). The grindstone A is configured to be able to contact and separate from the grindstone A inside the hole 2b1 in a direction perpendicular to the axis of the through hole 2b1. The movable portion 2c is separated from the grindstone A so that the gap between the surface of the grindstone A and the wall surface of the through hole 2b1 becomes a minute predetermined gap during the grinding process. When the grindstone adapter 2 holds the grindstone A at a predetermined gap between the grindstone A and the through hole 2b1, the pressing force of the adapter 2 in the pressing direction of the grindstone A from the rod 20b varies. And the whetstone A can be stably held in a state where the whetstone A is prevented from wobbling.
In addition, the movable portion 2c is moved toward the center of the through hole 2b1 at the time of non-machining than at the time of machining, and comes into contact with the grindstone A so as to sandwich the grindstone A between the wall surface of the through hole 2b1 and the grindstone A. Fix to the whetstone adapter 2.
[0014]
The drive section 3 is installed in a mounting hole 2a2 provided in the adapter body 2a such that one end opening communicates with the fitting hole 2a1. The driving unit 3 includes a piezo (piezoelectric) element arranged to be able to expand or contract in a direction perpendicular to the through hole 2b1. The movable portion 2c is linearly and minutely displaced by deforming the piezo element according to the input instruction signal (voltage signal).
[0015]
The control unit 5 has first adjusting means 5a for adjusting a voltage value for clamping for bringing the movable portion 2c into contact with the grindstone A and fixing it to the adapter 2, and a contact state between the movable portion 2c and the grindstone A. And a second adjusting means 5b for adjusting the voltage value for unclamping so that the gap between the whetstone A and the adapter 2 becomes a predetermined gap. The control unit 5 includes an amplifier 5c that amplifies the voltage of a power supply (not shown) based on the voltage value specified by the first adjusting unit 5a or the second adjusting unit 5b. The voltage applied to the piezo element of the drive unit 3 is continuously changed according to the adjustment value of the first adjustment unit 5a or the second adjustment unit 5b, and the fine adjustment of the displacement amount in the movable part 2c is smoothly performed. You can do it.
[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 the grinding process. The above gap can be maintained at an appropriate gap during grinding. That is, even when the wall surface of the through hole 2b1 is worn or when a new grindstone A is set on the grindstone adapter 2, the piezo of the drive unit 3 is appropriately adjusted by the first adjusting means 5a and the second adjusting means 5b. By adjusting the voltage applied to the element and slightly displacing the movable portion 2c in accordance with the wear dimension and the external dimension of the new 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 at an appropriate gap, and can prevent the processing accuracy of the inner ring 10 from being lowered. Further, at the time of non-machining, the movable portion 2c can contact the grindstone A so as to sandwich the grindstone A between the wall surface of the through hole 2b1 and fix the grindstone A to the grindstone adapter 2, so that the completed inner ring is formed. When taking out 10 or setting the next inner ring 10 in the superfinishing machine, the whetstone A can be reliably prevented from coming out of the through-hole 2b1. Therefore, continuous processing of the inner ring 10 can be performed stably.
[0017]
Further, in the present embodiment, by bringing the movable portion 2c into contact with the grindstone A, it is possible to reliably prevent the grindstone A from coming out of the grindstone adapter 2 irrespective of whether or not wear occurs on the grindstone adapter 2. There is no need to integrally connect the grindstone A and the piston rod 20b by using a connecting member such as a bolt screwed to the end of the grindstone or a chuck component for holding the end, and the work of replacing the grindstone A, etc. 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, but the present invention holds a grindstone that is rocked while being pressed against a processing surface. The present invention can be applied to various machine tools for performing a grinding process such as a finishing process on a processed surface.
Further, in the above description, the whetstone adapter 2 in which the movable portion 2c is provided on the sleeve member 2b having the through hole 2b1 has been described, but the present invention is not limited to this, and the through hole into which the whetstone is inserted, It is only necessary to provide a movable part that can be brought into contact with and separated from the grindstone inside the through hole. The presence or absence and shape of the sleeve member, the number and shape of the movable part, the control method, and the like are the same as those described above. Not limited. Specifically, a plurality of movable parts may be provided at regular intervals around the grindstone, and the movable parts may be moved to adjust the gap between the grindstone and the adapter or to lock the grindstone. Further, a configuration may be employed in which the gap adjustment and the grindstone lock are automatically performed by providing a detection unit for detecting the size of the gap and performing feedback control based on the gap detection value of the detection unit.
[0019]
Further, in the above description, the case where the driving section (moving means) 3 is constituted by using the piezo element has been described. However, the moving means of the present invention may be one that moves the movable portion 2c toward and away from the grindstone A. Instead, a micromotor or an electromagnet may be used instead of the piezo element. However, when these motors and electromagnets are used, it is necessary to provide a conversion member for converting the rotational motion of the motor into a linear motion, or to secure a larger installation space for the electromagnets than the piezo element. Therefore, it is preferable to use a piezo element which can easily simplify the structure of the drive unit 3 and can easily make the grinding wheel adapter 2 and, consequently, the grinding wheel holding mechanism 1 compact.
In the above description, the control unit 5 including the two adjusting means 5a and 5b has been described. However, for example, only the adjusting means for adjusting the voltage value for clamping is provided in the control unit, and the voltage value for unclamping is The voltage may be automatically applied by a circuit that lowers the voltage value for clamping by a predetermined voltage value.
Further, two piezo elements are arranged in two layers in the moving direction of the movable part 2c, and one and the other are respectively used as the moving means and the pressure sensor, and the applied voltage of the piezo element for the moving means is determined based on the sensor detection values. May be adjusted.
[0020]
【The invention's effect】
The present invention configured as described above has the following effects.
According to the whetstone holding mechanism of the first aspect, even when the wall surface of the through-hole is worn or when a new whetstone is set on the whetstone adapter, the movable part is minute according to the wear size and the outer dimensions of the new whetstone. By displacing, the gap can be maintained at an appropriate gap, so that unlike the conventional example, wobble of the grindstone caused by the spread of the gap can be reliably and easily prevented, and the processing accuracy of the work 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 work can be stably performed.
[0021]
According to the grinding wheel holding mechanism of the second aspect, the structure of the moving means can be simplified, so that the grinding wheel adapter and the grinding wheel holding mechanism can be easily made compact, and small and excellent in processing efficiency. The whetstone holding mechanism can be easily configured.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing a main part of a grinding wheel holding mechanism according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Whetstone holding mechanism 2 Whetstone adapter 2a Adapter body 2b Sleeve member 2b1 Through hole 2c Movable part 3 Drive unit (moving means, piezo element)
5 control unit (control means)
10 Inner ring (track ring)
10a Track surface A Whetstone

Claims (2)

A whetstone holding mechanism that performs a grinding process on the processing surface by being rocked while being pressed against the processing surface,
A through-hole for inserting the whetstone with a gap, and a whetstone adapter provided with a movable part capable of coming and going with respect to the whetstone inside the through-hole,
Moving means for moving the movable part toward and away from the whetstone,
Control means for controlling the driving of the moving means,
The control means separates the movable portion from the grindstone so that a gap between the grindstone and the through hole becomes a predetermined gap at the time of machining, and contacts the movable portion with the grindstone at the time of non-machining, thereby A whetstone holding mechanism, wherein a whetstone is fixed to the whetstone adapter. The whetstone holding mechanism according to claim 1, wherein the moving unit is configured using a piezo element.

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