JP3870950B2 - Grinding method for thin member with circular cross section and grinding method for inner ring of thin ball bearing - Google Patents

Description

  The present invention relates to a method for grinding a thin member with a circular cross section and a method for grinding a thin ball bearing inner ring.

  When grinding the outer peripheral surface of a workpiece made of a thin member having a circular cross section such as a thin ring or pipe with a rotating grinding wheel, the workpiece has low rigidity. Therefore, when the workpiece is cut with the grinding wheel, as shown in FIG. As shown in FIG. 10, the workpiece a is deformed and ground to a state where the roundness error is large. In FIG. 9, b is a grinding wheel for grinding the workpiece a, and c is a pair of shoes applied to the workpiece a.

  The following (1) and (2) can be considered as a method for preventing the deformation of the workpiece made of the thin member having a circular cross section as described above during grinding.

  (1) Forcibly press the workpiece so as not to deform.

  (2) The grinding resistance force in the radial direction of the workpiece during grinding is reduced.

  As a conventional example of the above (1), there is Patent Document 1 in a centerless grinding machine of a type using an adjustment wheel.

As shown in FIG. 11, in addition to the blade e, the grinding wheel f, and the adjustment wheel g that receive the cylindrical thin pipe d as a work from below, the cylindrical thin pipe d is appropriately pressed by the pressing roller h from above. And the rigidity of the cylindrical thin pipe d during grinding is compensated by suppressing the deformation of the cylindrical thin pipe d.
Japanese Utility Model Publication No. 63-12913

  In the method as shown in FIG. 11, it is necessary to provide a new mechanism. It is also conceivable to apply the method shown in FIG. 11 to a shoe-type infeed centerless grinding machine as shown in FIG. However, this shoe-type infeed method centerless grinding machine has a complicated mechanism and has a problem that it becomes an obstacle to the arrangement of the in-process gauge and loading device when it is automated.

  The present invention has been made in view of such problems of the prior art described above, and the object of the present invention is to improve the processing efficiency as much as possible by a simple mechanism, Grinding method and thin-walled ball bearing inner ring capable of grinding a thin-walled cross-section thin member or a thin-walled ball bearing inner ring with a high roundness while suppressing a decrease in roundness due to deformation of a workpiece made of a thin-walled ball bearing inner ring It is intended to provide a grinding method.

In order to achieve the above object, the grinding method for a thin member with a circular cross section according to the present invention supplies a workpiece made of a thin member with a circular cross section so as to be substantially parallel to the axial direction of a grinding wheel rotating in the central axis direction. A workpiece driving means for supporting the outer periphery of the workpiece together with the grinding wheel, supporting the workpiece by a workpiece supporting means for positioning in a plane orthogonal to the central axis of the workpiece, and rotating the workpiece around the central axis of the workpiece. In the grinding method of the thin cross-section thin member in which the grinding wheel is pressed against the outer peripheral surface of the work while being rotated by the workpiece, and the outer periphery of the work is ground by the grinding wheel, the outer peripheral surface of the work can be formed by the work supporting means. to support the portion of the narrow width (narrow grinding part) as long as before by the grinding wheel by pressing the grinding wheel to the narrow grinding portion Grinding the narrow grinding part, then, by supporting the narrow grinding portion by the workpiece supporting means, said a narrow grinding portion reference plane, the axial direction of the outer peripheral surface of said workpiece by said grinding wheel The remaining portion of the width is ground, and thereafter, the narrow-width ground portion in the axial direction and the remaining portion of the outer peripheral surface of the workpiece ground first are collectively ground by the grinding wheel.

In order to achieve the above object, the thin ball bearing inner ring grinding method of the present invention supplies a workpiece made of a thin ball bearing inner ring so as to be substantially parallel to the axial direction of the grinding wheel rotating in the central axis direction. The outer periphery of the workpiece is supported together with the grinding wheel, and the workpiece is supported by a workpiece support means that is positioned in a plane orthogonal to the central axis of the workpiece, and the workpiece is rotated about the central axis of the workpiece. In the grinding method of the thin ball bearing inner ring, wherein the grinding wheel is pressed against the outer circumferential surface of the workpiece while being rotated by the workpiece driving means, and the outer circumference of the workpiece is ground by the grinding wheel, the outer circumferential surface of the workpiece by the workpiece supporting means. to support the narrow width parts as possible (narrow grinding portion) by the grinding wheel by pressing the grinding wheel to the narrow grinding portion Grinding the serial narrow grinding part, then, as a reference surface of the narrow grinding portion, characterized by grinding the race surface of the workpiece.

According to the present invention, the work support means supports the narrowest possible part (narrow grinding part) of the outer peripheral surface of the work and presses the grinding wheel against the narrow grinding part to grind the narrow grinding part. As a result, the grinding force becomes smaller than when grinding the entire width of the outer peripheral surface of the workpiece. Therefore, the deformation of the workpiece during grinding of the narrow-width grinding portion is reduced, and the round-width grinding portion has a roundness error. Less grinding. As a result, the grinding portion of the workpiece made of the thin member having a circular cross section or the thin ball bearing inner ring has a roundness following the narrow grinding portion which is the reference surface, and a high roundness can be obtained.

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

  As a parameter approximately proportional to the grinding resistance, there is K obtained by the following equation (1).

K = V · b / λ (1)
However, V: Cutting speed in the workpiece radial direction b: Axial contact width between workpiece and grinding wheel λ: Sharpness of grinding wheel

  Note that as the parameter K is decreased, the grinding resistance decreases, leading to prevention of deformation of the workpiece. Since the method of increasing λ is determined by the grinding wheel, V or b may be decreased. Among these, in the present invention, a method of reducing the axial contact width b between the workpiece and the grinding wheel is selected, and the reason is to improve the processing efficiency as much as possible.

(First embodiment)
First, a first embodiment will be described with reference to FIGS.

  FIG. 1 is a plan view showing a part of a grinding apparatus by an infeed method for carrying out a grinding method of a circular thin section member according to the present embodiment, and FIG. 2 is a view taken in the direction of arrow A in FIG.

  1 and 2, reference numeral 1 denotes a backing plate, which is rotated counterclockwise in FIG. The backing plate 1, a motor and a spindle (not shown) constitute a work driving means. A thin ring (ring) member (circular thin section member) 2 as a work is set at one end of the backing plate 1 so as to be rotatable. The thin ring member 2 is attracted to the backing plate 1 by magnetic force.

  On the outer peripheral surface of the thin ring member 2, a front shoe (work support means) 3 and a rear shoe (work support means) 4 whose sliding surfaces are made of cemented carbide are applied. The member 2 is positioned and supported in a plane perpendicular to the axis. The rotation center axis of the backing plate 1 and the center axis of the thin ring member 2 determined by the two shoes 3 and 4 are slightly decentered from each other so that the thin ring member 2 is always pressed against the two shoes 3 and 4. The position is such that force acts. The thin ring member 2 is rotated at substantially the same speed as the backing plate 1 by the action of the backing plate 1 while the position of the thin ring member 2 in the plane perpendicular to the axis is determined by the action of the two shoes 3 and 4. .

  Both the shoes 3 and 4 are in contact with only the narrowest possible portion (the hatched portion in FIG. 1, hereinafter referred to as a narrow-width ground portion) 5 of the outer peripheral surface of the thin ring member 2. It is arranged like this. Reference numeral 6 denotes a grinding wheel for grinding a target portion of the outer peripheral surface of the thin ring member 2, which rotates in the clockwise direction in FIG. 2 around a rotation axis 7 parallel to the rotation axis of the thin ring member 2. Is. Further, the thin ring member 2 and the grinding wheel 6 can be moved within a predetermined range in the axial direction (in the directions of arrows B and C in FIG. 1) by an axial feed means (not shown). In an infeed grinding machine, axial feed is not necessary.)

  As shown in FIGS. 1 and 2, the thin ring member 2 and the grinding wheel 6 are moved by an axial feed means (not shown) so that the grinding wheel 6 contacts the outer peripheral surface of the narrow grinding portion 5 of the thin ring member 2. The front shoe 3 and the rear shoe 4 are respectively set in a predetermined state while being relatively moved in the axial direction for positioning. Then, by driving the backing plate 1 and rotating the grinding wheel 6, first, the narrow grinding portion 5 on the outer peripheral surface of the thin ring member 2 is ground. In this case, it is desirable to make the grinding width of the narrow grinding portion 5 as narrow as possible. By grinding the narrow grinding portion 5 on the outer peripheral surface of the thin ring member 2 in such an arrangement, the grinding force becomes smaller than when the entire outer peripheral surface width of the thin ring member 2 is ground. The deformation of the thin ring member 2 is reduced, and the narrow grinding portion 5 is ground with less roundness error. FIG. 3 shows the roundness in the case of grinding in this way.

  The diameter of the narrow grinding portion 5 is set slightly larger than the target value.

  Next, the entire width of the outer peripheral surface of the thin ring member 2 is ground using the narrow grinding portion 5 as a reference surface. That is, the grinding wheel 6 in the state of FIG. 1 is moved and positioned in one direction (arrow B direction) by an axial feed means (not shown) so as to come into contact with the full width of the outer peripheral surface of the thin ring member 2. To the state.

  The movement of the grinding wheel 6 in the axial direction can be easily performed with an NC drive grinder. Then, in the state of FIG. 4, the entire width of the outer peripheral surface of the thin ring member 2 is ground by rotating the grinding wheel 6. In this case, the narrow-width grinding portion 5 of the thin ring member 2 serving as the grinding reference surface is ground with a small roundness error as described above, and the thin ring member 2 follows the narrow-width grinding portion 5. Since the entire outer peripheral surface width is ground by the grinding wheel 6, the remaining surface 8 of the outer peripheral surface of the thin ring member 2 is substantially the same as the narrow grinding portion 5 until it has the same dimensions as the narrow grinding portion 5. Circularity can be obtained, and grinding can be performed efficiently.

  In order to grind the entire width of the outer peripheral surface of the thin ring member 2 between the narrow grinding portion 5 and the remaining surface 8 without steps, it is necessary to drive the grinding wheel 6 further than the size of the narrow grinding portion 5. Further, in order not to lose the good roundness of the narrow-width grinding portion 5, it is desirable that the amount of the grinding grinding of the grinding wheel 6 is a very small amount of about several μm. Thereby, favorable roundness is obtained over the full width of the outer peripheral surface of the thin ring member 2. FIG. 5 shows the roundness of the grinding part when the workpiece 2 is ground in this manner.

In this embodiment,
Use the grinding wheel 6 with an outer diameter of 300 mm.
The width of the workpiece 2 (axial length): 17 mm, whereas the initial grinding width: 2 mm.

  The reason for selecting a method for reducing the axial contact width between the workpiece 2 and the grinding wheel 6 as in the above-described embodiment will be described.

  That is, according to the above formula (1), in the case of the infeed method, considering that the grinding resistance is reduced to the same level as when grinding the narrow-width grinding portion 5, the method of reducing the cutting speed V in the radial direction of the workpiece 2 is When the cutting speed V is set to 2/17, a larger number of times of grinding is required.

  On the other hand, in the present embodiment, once the processing for forming the reference surface with a narrow width is performed, it can be ground without any problem by a normal grinding method thereafter.

  As described above in detail, according to the grinding method of the thin cross-section thin member according to the present embodiment, the grinding wheel 6 that rotates the target portion of the thin ring member (circular cross-section thin member) 2 that is a workpiece is ground. Prior to this, the narrowest possible part (narrow-width grinding part) 5 of the outer peripheral surface of the workpiece 2 is ground by the grinding wheel 6. Accordingly, since only a small grinding force is generated, the deformation of the workpiece 2 is small, and the narrow-width grinding portion 5 is ground with high roundness. Next, by supporting the narrow grinding portion 5 by the work support means 3, 4, using the narrow grinding portion 5 as a reference surface, the remaining portion of the axial width of the outer peripheral surface of the workpiece 2 is the grinding wheel. Then, the narrow grinding portion 5 and the remaining portion in the axial direction of the outer peripheral surface of the workpiece 2 that have been ground first are collectively ground by the grinding wheel 6. As a result, the workpiece 2 is deformed during the grinding, but the grinding portion of the workpiece 2 has a roundness that follows the narrow-width grinding portion 5 that is a reference surface, and a high roundness is obtained.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS.

  6 and 7 are plan views showing a part of an infeed grinding apparatus for carrying out the grinding method for the thin ball bearing inner ring according to the present embodiment. In both figures, the same parts as those in FIG. 1 of the first embodiment are denoted by the same reference numerals.

  The present embodiment is different from the first embodiment described above in that the configuration of the grinding wheel and the workpiece are the thin-walled ball bearing inner ring 2 ', and the race surface is ground. That is, the grinding wheel 6 'in the present embodiment has a straight portion 6a at one end side from the substantially intermediate portion in the axial direction of the outer peripheral surface, and an R portion 6b at the other end side from the substantially intermediate portion in the axial direction of the outer peripheral surface. It is said that. Then, as shown in FIG. 6, the thin ball bearing inner ring 2 ′, the front shoe 3, the rear shoe 4 and the grinding wheel 6 ′ are set in the same manner as in the first embodiment, and the grinding wheel 6 ′ is rotated. Thus, first, the narrowest possible portion (narrow grinding portion) 5 of the outer peripheral surface of the thin ball bearing inner ring 2 ′ is ground by the straight portion 6a of the outer peripheral surface of the grinding wheel 6 ′.

  Next, the race surface 9 of the thin ball bearing inner ring 2 ′ is ground using the narrow grinding portion 5 as a reference surface. That is, the grinding wheel 6 ′ in the state of FIG. 6 is moved so that the R portion 6 b is in contact with the race surface 9 of the thin ball bearing inner ring 2 ′ to be in the state of FIG. 7. Then, the race surface 9 of the thin ball bearing inner ring 2 ′ is ground by rotating the grinding wheel 6 ′. In this case, the narrow-width ground portion 5 of the thin ball bearing inner ring 2 ′ serving as the grinding reference surface is ground with a small roundness error as described above, and the thin-wall ball bearing follows this narrow-width ground portion 5. Since the race surface 9 of the inner ring 2 ′ is ground, the race surface 9 has substantially the same roundness as the narrow-width grinding portion 5 and can be ground efficiently.

  Also in the present embodiment, a method for reducing the axial contact width b between the workpiece 2 'and the grinding wheel 6' is selected as in the first embodiment described above.

  According to the thin ball bearing inner ring grinding method according to the present embodiment, prior to grinding the target portion of the thin ball bearing inner ring 2 ′, which is a workpiece, with the rotating grinding wheel 6 ′, first, the workpiece 2 ′ The narrow grinding portion 5 on the outer peripheral surface of the workpiece 2 is ground with the grinding wheel 6 ′, and then the race surface 9 of the workpiece 2 ′ is ground using the narrow grinding portion 5 as a reference surface. As a result, the workpiece 2 ′ is deformed during the grinding, but the grinding portion of the workpiece 2 ′ has a roundness that follows the narrow-width grinding portion 5 that is a reference surface, and a high roundness is obtained.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG.

  FIG. 8 is a plan view showing a part of a grinding apparatus using a through-feed method for carrying out the grinding method for a thin member with a circular cross section according to the present embodiment.

  In the figure, the same parts as those shown in FIG. 1 of the first embodiment are denoted by the same reference numerals.

  This embodiment differs from the first embodiment described above in that both the first and second embodiments described above are applied to grinding by the infeed method. The form is that it is applied to grinding of the through-feed method.

  That is, as shown in FIG. 8, there is a predetermined interval in the axial direction on the outer peripheral surface of the grinding wheel 6 '' having an axial length longer than the axial length of the grinding wheel in the first and second embodiments described above. A plurality of (for example, 40) annular grooves 10 are provided, and a plurality of (for example, 10) thin ring members 2 serving as workpieces are provided between the grinding wheel 6 ″ and the adjustment wheel 11 made of a rubber wheel. While rotating in a state where they are arranged in a direction, they are moved in the direction of the arrow in the figure and ground.

  The plurality of thin ring members 2 are supported by a blade (not shown) disposed below the plurality of thin ring members 2. The blade and the adjustment wheel 11 constitute a work support means. Further, a work driving means for rotating the work 2 by the adjusting wheel 11 is configured. Further, the center axis of the adjusting wheel 11 is decentered from the center axis of the workpiece 2 and the center axis of the grinding wheel 6 ″ by a predetermined angle (for example, about 3 degrees), thereby arranging the workpiece 2 in the direction of the arrow in the figure. A workpiece feed means for moving is configured.

  In the figure, reference numeral 12 denotes a groove forming means for forming the annular groove 10 in the grinding wheel 6 ″, and the groove forming means 12 may also be used as a dresser.

  Next, the operation of the grinding apparatus for carrying out the grinding method of the thin cross-section member according to the present embodiment will be described.

  First, dressing and grooving are performed to form a plurality of annular grooves 10 on the outer peripheral surface of the grinding wheel 6 ". Next, the grinding wheel 6" and the adjustment wheel 11 are driven to rotate, and a plurality of thin ring members are formed. While rotating 2, the outer peripheral surface of each thin ring member 2 is ground by a grinding wheel 6 ″ by continuously moving in the direction of the arrow in FIG. 8.

  In the present embodiment, the dressing of the grinding wheel 6 ″ and the groove processing of the annular groove 10 are performed separately. However, the present invention is not limited to this. You may make it perform groove processing simultaneously.

  In the present embodiment, the thin ring member 2 is ground under the following conditions.

Condition Outer diameter of grinding wheel 6 ": 300mm
Groove width of the annular groove 10: 3 mm
Groove interval of the annular groove 10: 3 mm
Groove depth of the annular groove 10: several tens of μm to 1 mm
Work 2 width (axis length): 20 mm
If the groove depth of the annular groove 10 is too deep, there is a problem that the strength of the grinding wheel 6 ″ is lowered.

  Even in the through-feed method as in the present embodiment, by providing the annular groove 10 on the outer peripheral surface of the grinding wheel 6 ″ so that the contact width between the grinding wheel 6 ″ and the workpiece 2 is reduced, the same grinding wheel is used. In the cutting feed in the radial direction, the grinding resistance is reduced by the amount of the annular groove 10, and the number of times of grinding can be reduced as in the first and second embodiments described above, and the processing efficiency is improved.

  On the other hand, if the grinding resistance is reduced by a normal grinding wheel without the annular groove 10, the cutting feed of the grinding wheel has to be reduced, and the number of times of grinding is required accordingly.

  In the present embodiment, the plurality of thin ring members 2 are continuously fed and ground in the axial direction while rotating in an axial direction, so that the productivity is high.

  In the present embodiment, a plurality of thin ring members 2 are continuously fed in the axial direction and rotated while being arranged and rotated in the axial direction. However, the present invention is not limited to this. It can also be applied to other workpieces.

  In the present embodiment, the grooves on the outer peripheral surface of the grinding wheel 6 ″ are a plurality of annular grooves 10 having a predetermined interval in the axial direction. However, the present invention is not limited to this, and for example, a continuous spiral shape. It may be a groove.

  Also in the grinding method of the thin cross-section member according to the present embodiment, the same effect as the grinding method of the thin cross-section member according to the first embodiment described above is obtained.

It is a top view which shows a part of grinding apparatus for enforcing the grinding method of the cross-section circular thin member which concerns on 1st Embodiment. It is A arrow directional view of FIG. It is a figure which shows the roundness at the time of grinding with the grinding method of the cross-section circular thin member which concerns on 1st Embodiment. It is a top view which shows a part of grinding apparatus for enforcing the grinding method of the cross-section circular thin member which concerns on 1st Embodiment. It is a figure which shows the roundness at the time of grinding with the grinding method of the cross-section circular thin member which concerns on 1st Embodiment. It is a top view which shows a part of grinding apparatus for enforcing the grinding method of the thin ball bearing inner ring which concerns on 2nd Embodiment. It is a top view which shows a part of grinding apparatus for enforcing the grinding method of the thin ball bearing inner ring which concerns on 2nd Embodiment. It is a top view which shows a part of grinding apparatus for enforcing the grinding method of the cross-sectional circular thin member which concerns on 3rd Embodiment. It is a figure for demonstrating the problem in the grinding method of the conventional cross-section circular thin member. It is a figure which shows the roundness at the time of grinding with the grinding method of the conventional cross-sectional circular thin member. It is a figure which shows a part of conventional grinding apparatus of a cross-sectional circular thin wall member. It is a figure which shows the case where the grinding method by the grinding apparatus of a cross-sectional thin thin member shown in FIG. 11 is applied to a shoe type centerless grinding machine.

Explanation of symbols

1 Backing plate (work drive means)
2 Circular thin-walled member (work)
2 'circular thin-walled member (work)
3 shoes (work support means)
4 Shoe (work support means)
5 The narrowest possible part of the circumferential surface of the thin circular member (narrow grinding part)
6 Grinding wheel 6 'Grinding wheel 6 "Grinding wheel 11 Adjustment wheel (work support means, work drive means)

Claims (3)

A workpiece made of a thin member with a circular cross section is supplied so as to be substantially parallel to the axial direction of the grinding wheel rotating in the central axis direction, and the outer periphery of the workpiece is supported together with the grinding wheel, and is orthogonal to the central axis of the workpiece. While supporting the work by a work support means for positioning in a plane and rotating the work by a work driving means for rotating the work around a central axis of the work, the grinding wheel is pressed against the outer peripheral surface of the work, In the grinding method of the cross-section circular thin member that grinds the outer periphery of the workpiece with a grinding wheel
The workpiece support means supports the narrowest possible portion (narrow grinding portion) of the outer peripheral surface of the workpiece, and presses the grinding wheel against the narrow grinding portion to narrow the grinding by the grinding wheel. Grinding the portion, and then supporting the narrow grinding portion with the workpiece support means, using the narrow grinding portion as a reference surface, and using the grinding wheel, the remainder of the axial width of the outer peripheral surface of the workpiece A method for grinding a circular thin-walled member, characterized in that a portion of the outer peripheral surface of the workpiece, which has been ground first, is then ground together with a grinding wheel and the remaining portion is ground together with the grinding wheel. . A work consisting of an inner ring of a thin ball bearing is supplied so as to be substantially parallel to the axial direction of the grinding wheel rotating in the central axis direction, and the outer periphery of the work is supported together with the grinding wheel and orthogonal to the central axis of the work While supporting the work by a work support means for positioning in a surface to be rotated, and pressing the grinding wheel on the outer peripheral surface of the work while rotating the work by a work driving means for rotating the work around the central axis of the work, In the grinding method of the thin-walled ball bearing inner ring for grinding the outer periphery of the workpiece with the grinding wheel,
The workpiece support means supports the narrowest possible portion (narrow grinding portion) of the outer peripheral surface of the workpiece, and presses the grinding wheel against the narrow grinding portion to narrow the grinding by the grinding wheel. A method for grinding a thin-walled ball bearing inner ring, comprising grinding a portion and then grinding the race surface of the workpiece using the narrow grinding portion as a reference surface.   The grinding method according to claim 1 or 2, wherein the work support means comprises two shoes and the work drive means comprises a motor, a spindle and a packing plate.

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