JP2012187648A - Method for grinding inner surface of workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for grinding an inner surface of a workpiece, capable of cutting into high-accuracy profiles of arbitrary shapes such as an ellipse, a triangle, and the like on an inner surface of a workpiece by using a general-purpose inner surface grinding machine.SOLUTION: A jig J having a profile shaped similarly to a requested inner-surface profile formed on its outer circumference is fitted onto a cylindrical outer-diameter surface of the workpiece W, a fitted assembly A of the workpiece W and the jig J is attracted and supported by an attractive surface of a drive plate 1 which is rotationally driven unidirectionally, and the fitted assembly A is rotated while supporting an outer circumference of the fitted assembly A by a plurality of shoes 2a and 2b. A grinding wheel 4 is pushed against the inner surface of the workpiece W, and the inner surface of the workpiece W is ground by rotationally moving the grinding wheel 4 in a radial direction of the workpiece W.

Description

  The present invention relates to a method for grinding a work inner surface for grinding a required profile on a work inner surface.

  Grinding the work inner surface using an internal grinder has been conventionally performed, but using a general-purpose internal grinder to grind an inner profile with a special shape such as an ellipse on the inner circumference of the work Can not.

  For this reason, when grinding a specially shaped inner surface profile on the inner periphery of the workpiece, a CNC grinder by computer numerical control as described in Patent Document 1 is generally used. However, the CNC grinder is extremely expensive, the equipment is expensive, and it is necessary to make the grinding wheel perform a useless movement, so that there is an inconvenience that processing takes time.

  Patent Documents 2 to 5 propose machining techniques that allow the inner circumference of a workpiece to be elliptically ground by adding a special mechanism to a lathe that does not have a cam grinding function or a grinding machine. It is impossible to grind the inner profile of a special shape other than an ellipse such as a triangle.

  Here, as a grinding method for grinding a non-circular inner profile formed of a polygon such as a triangle on the inner periphery of a workpiece, the one shown in FIG. 6 is conventionally known. In this grinding method, the cylindrical workpiece W is clamped from the outer diameter side by the three outer claws 21 of the chuck 20 attached to the end of the main shaft, and each outer claw 21 has a uniform outer diameter surface of the workpiece W. The workpiece W is elastically deformed in a triangular shape by the action of pressing in the direction, the grinding wheel 22 is pressed against the inner surface of the workpiece W rotating with the main shaft, the inner surface is ground into a perfect circle, and then the outer claws are moved outward. The workpiece is released from the movement. As shown in FIG. 7, the workpiece W is restored in shape by its own restoring elasticity, and the outer peripheral surface which is not ground becomes cylindrical, and the ground inner surface becomes a triangle. An inner surface profile having a desired shape is formed on the inner periphery.

JP 2002-103193 A JP 2001-293647 A JP 2002-321102 A Japanese Patent Application Laid-Open No. 7-136821 JP 7-156006 A

  By the way, in the grinding method shown in FIG. 6, since the shape of the workpiece W after grinding is restored to a predetermined inner surface profile by restoring elasticity, the thickness of the workpiece W is sufficiently thin, about several tens μm to 100 μm. It is only possible to deal with non-circular shapes within the range of elastic deformation.

  Further, if there are protrusions or flanges on the outer periphery of the work W, it is difficult to elastically deform uniformly over the entire circumferential direction, and a highly accurate inner surface profile cannot be obtained.

  The object of the present invention is high accuracy of an arbitrary shape such as an ellipse or a triangle on the inner periphery of the workpiece using a general-purpose internal grinding machine, even for thick workpieces and workpieces having protrusions and flanges on the outer periphery. An object of the present invention is to provide a method for grinding an inner surface of a work so that an inner surface profile can be ground.

  In order to solve the above problems, in the present invention, a jig having a profile similar to the required inner surface profile formed on the outer periphery is fitted to the cylindrical outer diameter surface of the workpiece, and the workpiece and the jig The fitting assembly is sucked and supported by a suction surface of a drive plate that is driven to rotate in one direction, and the fitting assembly is rotated while the outer periphery of the fitting assembly is supported by a plurality of shoes. A configuration in which the grinding wheel is pressed against the inner surface, moved in the radial direction of the workpiece while the grinding wheel is rotated, and the workpiece inner surface is ground, and a surface having the same shape as the outer peripheral profile of the jig is ground on the inner surface of the workpiece. Adopted.

  If comprised as mentioned above, since the grinding wheel grinds the inner surface of a workpiece | work with the distance with the outer periphery of a jig | tool constant, the profile of a jig outer periphery will be formed in the inner surface of a workpiece | work.

  Here, if the center of the workpiece is offset with respect to the rotation center of the drive plate, the outer periphery of the jig is always pressed against the shoe, so that the inner periphery of the workpiece can be stably ground. At this time, the offset amount is equal to or greater than the strain amount with respect to the perfect circle of the outer peripheral profile of the jig, specifically, about several hundred μm to several mm.

  If the workpiece rotation is unstable due to the fitting assembly mounting error to the drive plate, or if the jig's outer profile has a larger distortion than the offset, the jig will rotate to the outer circumference of the jig. When a possible clamping roller is contacted and the mating assembly is pressed against the work support surface of the shoe by the clamp roller, the mating assembly rotates while maintaining contact with the work support surface of the shoe. Therefore, the work inner surface can be ground stably and accurately.

  In this invention, as described above, a jig having a profile similar to the required inner surface profile formed on the outer periphery is fitted to the cylindrical outer diameter surface of the workpiece, and the outer periphery of the jig is supported by a plurality of shoes. In this rotating state, the grinding wheel is brought into contact with the inner surface of the workpiece and the inner surface of the workpiece is ground, so that the grinding wheel grinds the inner circumference of the workpiece with a constant distance from the jig outer circumference. An inner surface profile identical to the profile of the jig outer periphery can be formed, and an inner surface profile of an arbitrary shape such as an ellipse or a triangle can be ground on the inner periphery of the workpiece using a general-purpose inner surface grinding machine.

  Moreover, even for thick workpieces, unequal thickness workpieces, or workpieces having flanges or protrusions on the outer periphery, an inner surface profile having the same shape as the outer periphery profile of the jig can be formed on the inner periphery of the workpiece.

(I) is a longitudinal sectional view showing an outline of a grinding apparatus for carrying out a grinding method for an inner surface of a workpiece according to the present invention, and (II) is a side view of (I). (III) is a longitudinal sectional view showing an example of processing when a triangular inner profile is formed on the inner periphery of the workpiece, and (IV) is a side view of (III). (V) is a longitudinal sectional view showing an example of processing in the case of forming a triangular inner profile with respect to the inner periphery of a work having protrusions on the outer periphery, and (VI) is a side view of (V). Side view showing another example of workpiece stabilization support means Longitudinal sectional view showing an example of processing when grinding an annular groove on the work inner surface Side view showing a conventional grinding method for forming a triangular inner profile on the inner periphery of a workpiece Longitudinal section showing the workpiece after grinding

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 (I) and 1 (II) show a working example in which a substantially triangular profile is ground on the inner periphery of a workpiece W using an internal grinding machine.

  The internal grinding machine includes a drive plate 1 that sucks and supports the workpiece W, a pair of shoes 2a and 2b that support the outer periphery of the workpiece W that is sucked and supported by the drive plate 1, and a grinding wheel 4 that grinds the inner periphery of the workpiece W. have.

  The drive plate 1 is attached to the tip of a main shaft (not shown) via a magnet chuck and rotates together with the main shaft. The tip of the drive plate 1 serves as a suction surface 1a, and the workpiece W is sucked and supported by the suction surface 1a. Yes.

  Of the pair of shoes 2a and 2b, one shoe 2a is disposed at a position facing the lower outer periphery of the workpiece W supported by suction on the suction surface 1a of the drive plate 1, and the other shoe 2b is the outer back of the workpiece W. It is arrange | positioned in the position facing.

  When grinding the inner surface of the workpiece W into an elliptical shape, a jig J having a profile similar to the elliptical profile formed on the outer periphery is fitted to the cylindrical outer diameter surface 10 of the workpiece W, and the fitting set The solid A is sucked and supported by the suction surface 1a of the drive plate 1, and the fitting assembly A is rotated in a state where the outer periphery of the fitting assembly A is supported by the work supporting surfaces 3 of the pair of shoes 2a and 2b. The grinding wheel 4 is pressed against the inner surface of W and moved in the radial direction of the workpiece W in a state where the grinding wheel 4 is rotated to grind the inner surface of the workpiece W.

  Here, the grinding wheel 4 is rotated in the same direction as the rotation direction of the workpiece W, and the rotation speed thereof is made different from the rotation speed of the workpiece W. When the grinding wheel 4 grinds the inner surface of the workpiece W, the grinding wheel 4 grinds the inner surface of the workpiece W at a constant distance from the outer periphery of the jig J. For this reason, an inner surface profile having the same shape as the outer peripheral profile of the jig J is accurately formed on the inner surface of the workpiece W.

  In addition, when the workpiece W is rotated with respect to the jig J during internal grinding of the workpiece W, a highly accurate inner surface profile cannot be formed on the inner surface of the workpiece W. The attachment is made strong so that it does not rotate relatively by press fitting or the like.

  As described above, since the grinding wheel 4 grinds the inner surface of the workpiece W at a constant distance from the outer periphery of the jig J, as shown in FIGS. 2 (III) and (IV), the outer peripheral profile is a triangular jig. When J is used, a triangular inner surface profile can be formed on the inner periphery of the workpiece W.

  Further, as shown in FIG. 5, when a jig J having a cylindrical outer peripheral profile and a grinding wheel 4 having an outer peripheral arc shape is used, an annular groove 6 is formed on the inner periphery of the workpiece W. It is also possible to grind the raceway groove of the bearing outer ring.

  Thus, since the outer peripheral profile of the jig J can be formed on the inner periphery of the workpiece W, by forming a profile having a similar shape to the required inner surface profile on the outer periphery of the jig J, the curvature in the circumferential direction can be increased. If the jig J is smoothly rotated by the support by the shoes 2a and 2b and the drive by the drive plate 1 and the shape of the workpiece W is smoothly changed, the inner periphery of the workpiece W is aimed. The inner surface profile can be formed with high accuracy.

  Further, even if the workpiece W has a thick or unequal thickness or a workpiece W having protrusions 7 or flanges on the outer periphery as shown in FIG. 3, the profile of the jig outer periphery is the same as the profile of the jig outer periphery. A profile of shape can be formed.

  In forming a profile for the outer periphery of the jig J, a profile of an arbitrary shape can be formed relatively easily and accurately by adopting a CNC grinder, a jig borer, or a wire cut electric discharge machining apparatus.

In the internal grinding of the workpiece W by the grinding wheel 4, if the center O _{1 of the} workpiece W is offset with respect to the rotation center O ₂ of the drive plate 1 as shown in FIG. As a result, the outer periphery of the jig J is always pressed against the work support surface 3 of the shoes 2a and 2b, and the fitting assembly A rotates stably, so that the inner surface of the work W can be ground stably and with high precision. it can. At this time, the offset amount δ is equal to or larger than the strain amount with respect to the perfect circle of the outer peripheral profile of the jig J, and specifically, about several hundred μm to several mm.

  FIG. 4 shows a case where the rotation of the workpiece W is unstable due to an attachment error of the fitting assembly A to the drive plate 1 or the amount of distortion with respect to the perfect circle of the outer periphery profile of the jig J is larger than the offset amount δ. In this manner, the rotatable clamp roller 8 is brought into contact with the outer periphery of the jig J in the fitting assembly A, and the workpiece W is pressed by the clamp roller 8 against the workpiece supporting surface 3 of the shoes 2a, 2b. By grinding the inner surface, the inner surface of the work W can be stably and accurately ground.

  Here, in FIG. 4, a clamp roller 8 is rotatably supported by a free end of a roller arm 11 that can swing around a shaft 9, and a cylinder 12 that is connected midway in the length direction of the roller arm 11. Thus, the fitting assembly A is pressed against the work support surface 3 of the shoes 2a and 2b via the clamp roller 8. However, instead of the cylinder 12, the clamp roller 8 is fitted with the fitting assembly A by a spring. The roller arm 11 may be urged in the direction of pressing.

  The outer periphery of the grinding wheel 4 is made to coincide with the required cross-sectional shape of the inner surface profile. For example, when the cross-sectional shape of the inner surface profile is a straight shape, it is a cylindrical shape, and when the inner surface profile is a tapered shape, it is a tapered shape.

W Work J Jig A Fitting assembly 1 Drive plate 2a Shoe 2b Shoe 3 Work support surface 4 Grinding wheel 8 Clamp roller

Claims (3)

  A drive plate in which a jig having a profile similar to the required inner surface profile is formed on the outer peripheral surface of the workpiece and the outer periphery of the workpiece is rotated in one direction. The suction assembly is supported by suction, the fitting assembly is rotated in a state where the outer periphery of the fitting assembly is supported by a plurality of shoes, the grinding wheel is pressed against the inner surface of the workpiece, and the grinding wheel is rotated. The workpiece inner surface is ground by grinding the inner surface of the workpiece by moving it in the radial direction of the workpiece and grinding the surface having the same shape as the outer peripheral profile of the jig on the inner surface of the workpiece.   The workpiece inner surface grinding according to claim 1, wherein the workpiece inner surface is ground in a state where the center of the workpiece is offset with respect to the rotation center of the drive plate and the outer periphery of the fitting assembly is pressed against the workpiece supporting surface of the shoe. Processing method.   2. The work inner surface is ground according to claim 1, wherein a rotatable clamp roller is brought into contact with an outer periphery of the jig of the fitting assembly, and the inner surface of the workpiece is ground in a state in which the fitting assembly is pressed against the workpiece supporting surface of the shoe. Grinding method for work inner surface.

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