JP2017035758A - Crowning method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and surely perform processing with a sufficient drop amount (crowning amount) even at the crowning of an extremely small curvature radius R.SOLUTION: In a crowning method which uses a through-feed super finishing machine, presses a workpiece W which is conveyed by a feed roller to a grindstone S, and applies crowning to an end part of the workpiece W by reciprocating the grindstone S, the grindstone S is fixed to a free end D of a link mechanism 30, and the grindstone S is oscillated in a plane in which the workpiece W draws a moving trajectory.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a crowning method and apparatus, which is not intended to be limited, but can be used to crown the outer diameter surface of a roller bearing roller.

  Rolling bearing rollers are usually made of high-quality bearing steel, and include cylindrical rollers, needle rollers, tapered rollers, and spherical rollers. Cylindrical rollers are used for cylindrical roller bearings, and the generatrix of the outer diameter surface is basically a straight line and parallel to the central axis of the roller. The needle roller is a cylindrical roller having a large length to diameter ratio and a small diameter. A tapered roller is a roller in which the generatrix of the outer diameter surface is basically a straight line and intersects the central axis of the roller. A spherical roller is a roller whose outer diameter surface has a convex curvature on a plane including the central axis of the roller.

  The outer diameter surface of the roller is also called a rolling surface, and is the surface of the roller that is in rolling contact with the raceway, so that it is finished with high accuracy. In addition, for the main purpose of preventing concentrated stress generated at the end of the contact portion with the raceway, there is a case where a process, that is, crowning, is applied to give a very slight curvature to the raceway or the roller bus. When the roller and the raceway are in a theoretical line contact, a considerably larger stress (edge load) is generated at the end of the roller than at the center portion, and the bearing life is significantly reduced. In order to prevent this, in the vicinity of the end of the roller, the rolling surface of the roller or the generatrix of the raceway surface is slightly curved so that it does not contact when there is no load. By doing in this way, the edge load of the edge part of the roller at the time of load can be reduced.

  In order to efficiently superfinish the outer diameter surface of the roller bearing roller, a method using a through feed superfinishing machine is known. The through-feed superfinishing machine uses a pair of drive rolls (hereinafter referred to as feed rolls) in which the feed rolls are arranged substantially in parallel and the distance between them is smaller than the workpiece (roller) diameter. In the feed roll, for example, one feed roll is disposed horizontally and the other feed roll is disposed at a predetermined angle with respect to the horizontal, and the angle is referred to as a through feed angle. Alternatively, one feed roll may be disposed with an inclination of α / 2 above the horizontal direction, and the other feed roll may be disposed with an inclination of α / 2 downward with respect to the horizontal direction. The relative inclination angle α between the two corresponds to the through feed angle.

  By providing the through-feed angle, a conveying force is generated in the axial direction of the feed roll when the feed roll is rotated in the same direction. That is, when a workpiece is supplied between the feed rolls in a posture in which the rotation axis coincides with the rotation axis of the feed roll, the workpiece moves in the axial direction while rotating on the pair of feed rolls.

  The outer diameter surface of the workpiece is uniformly processed by pressing the grindstone against the workpiece on the feed roll while continuously feeding the workpiece, and applying a reciprocating motion (oscillation) parallel to the workpiece axis to the grindstone. At this time, the grindstone is constrained in degrees other than the vertical direction by the grindstone holder, and is usually pressurized from above by the air cylinder. The grindstone holder and the air cylinder are fixed to the oscillation head to constitute an oscillation unit, and the oscillation is given to the grindstone by finely moving the oscillation unit substantially parallel to the workpiece axis.

  Patent Document 1 describes the following technique as related to crowning processing using a through-feed superfinishing machine. That is, a plurality of convex portions with different curvature radii are formed in the axial direction at positions facing each other on the feed roll, and the curvature radius smoothly changes to the outer peripheral surface of the substantially cylindrical workpiece that is fed between the feed rolls and rotates. A curve having a crowning amount is formed. When the workpiece moves between a pair of opposing contact portions, the cross-sections in the axial direction of the plurality of contact portions have different contours. Therefore, the workpiece moves between the contact portions along different tracks, and The outer peripheral surface of the workpiece is processed into different shapes.

  For example, when machining into a gentle shape, the grindstone is pressed when the workpiece passes between gently shaped contact parts, and when machining a hard part with a slant, the work has a slanted shape. When passing between the contact parts, the grindstone is pressed and processed. Then, by combining the processing between the contact portions, a generatrix shape of a desired workpiece as a whole, for example, a straight shape, a single R shape, or a crowning shape formed by joining a plurality of arcs having different curvature radii is obtained. The grindstone is guided and held so as to be slidable in the vertical direction, and is pressed down by a piston / cylinder mechanism to press the work surface having a shape along the workpiece feed against the workpiece.

  In Patent Document 2, in a processing method in which a cylindrical member is inserted from one side by a conveying roller, an end portion of the cylindrical member is superfinished, and is taken out from the traveling direction as it is, the crowning shapes at both ends of the cylindrical member are likely to be asymmetric. It is based on the recognition of the problem. And in order to make the both ends of a workpiece | work become the same crowning, the technique which makes a workpiece | work reciprocate by rotating a feed roll forward and backward is described.

  As a processing apparatus, a feed roll and two or more sets of grindstone units are used. A feed roll is arranged with one feed roll inclined at an angle of α / 2 above the horizontal direction and the other feed roll arranged at an angle of α / 2 below with respect to the horizontal direction. An inclination angle is provided. Each grindstone unit is composed of a superfinishing grindstone unit that moves up and down only when viewed from the center of the feed roll, and a superfinishing grindstone unit that moves up and down and oscillates. . The head swing in this case is a movement for changing the contact angle with the workpiece according to the traveling direction of the workpiece.

  Patent Document 3 describes a technique of imparting a crowning shape with a through-feed superfinishing machine using a feed drum having a spiral groove on the outer periphery when machining the outer diameter surface of a tapered roller. The outer diameter surface of the tapered roller is composed of a straight straight portion and crowning portions formed at both ends in the axial direction of the straight portion, and the outer diameter surface of the roller is inclined with respect to the processing surface of the grindstone. In this state, the rollers are moved and processed in the conveying direction while rotating.

  The processing apparatus includes a pair of feed drums and a grindstone. The feed drum has a helical guide screw surface on its outer periphery, and is driven to rotate around the central axis. The pair of feed drums includes a male feed drum and a female feed drum, and the guide screw surface of the male feed drum is partitioned from the adjacent peripheral surface portion by a spiral collar portion. When the feed drum is rotated in a state where the large end surface of the roller is in contact with the collar portion, the roller is transported from the upstream side to the downstream side in the transport direction with the small end surface facing forward (that is, the transport direction).

  The guide screw surface is divided into two divided screw surface portions arranged in the axial direction so as to support the outer peripheral surface of the roller at two positions on the front and rear sides of the roller. A circumferential groove is formed between the axially divided screw surface portions defined by the flange portions. Between the collar portion and the divided screw surface portion, a circumferential groove narrower than the circumferential groove between the divided screw surface portions is formed. The female-side feed drum 2 is not provided with a collar portion, and is composed of a guide screw surface including two divided screw surface portions arranged in the axial direction that support the outer peripheral surface of the roller at two positions on the front and rear sides of the roller.

  The inclination angle of the straight line connecting the two roller contact points to the grinding surface of the grindstone with respect to the feed drum axis is continuously changed from large to small to large as it goes from the upstream side to the downstream side in the roller conveyance direction. The split screw surface portion of the feed drum is formed. Then, when the tapered roller is passed from the upstream position in the conveying direction of the feed drum to the intermediate position, the crowning portion on the small end surface side of the outer peripheral surface of the tapered roller is superfinished at the lower end edge of the grindstone. After that, when the tapered roller is passed from the intermediate position in the conveying direction of the feed drum to the downstream position, the crowning portion on the large end surface side of the outer peripheral surface of the tapered roller is superfinished with the lower end edge of the grindstone. .

  A plurality of plate-like grindstones are arranged in parallel to the axial direction of the feed drum, and are arranged so that the lower edge of the grindstone processing surface is inserted between both feed drums. The grindstone is swingably supported by the support member, and each grindstone can be swung parallel to the central axis with respect to the support member (see FIGS. 9 and 10 of Patent Document 3). That is, when the roller is conveyed with the crowning portion of the roller hitting the lower edge of the grindstone, the grindstone is oscillated and displaced accordingly. When the rollers are conveyed from the upstream side to the downstream side in the conveyance direction of the feed drum, the grinding stone is slightly swung and displaced with respect to the crowning portion of the roller, and the outer circumference of the roller with respect to the lower edge of the processing surface of the grinding stone By transporting the inclined surface, a crowning portion with a minute curvature is obtained.

JP 2004-322307 A JP 2005-118926 A JP 2012-061571 A

  It is known that when a roller contacts a flat surface or another cylindrical surface over the entire length under a certain load condition, an edge load is generated at both ends of the roller. In order to avoid or mitigate this, it is effective to provide crowning at both ends of the roller, and it is theoretically ideal that the axial section has a logarithmic shape with a radius of curvature that decreases toward the end. Has been shown. Since it is extremely difficult to create such a theoretical logarithmic curve shape industrially, a “composite arc” composed of a plurality of arcs having different curvature radii is usually used as a crowning shape.

  However, in the through-feed superfinishing machine, the grindstone holder and the air cylinder are fixed to the oscillation head, and the oscillation head is restrained by a linear guide or a similar mechanism. Therefore, the oscillation of the grindstone itself occurs only in the direction parallel to the rotation axis of the feed roll. Since the oscillation amplitude is at most several millimeters, there is no significant problem when the radius of curvature R of the crowning is sufficiently large, and a crowning shape almost corresponding to the trajectory of the workpiece can be obtained. However, when the radius of curvature R of the crowning becomes small, the rocking locus of the grindstone that should originally follow the radius of the movement trajectory of the workpiece is linear, so that the contact between the grindstone and the workpiece becomes intermittent, resulting in abnormalities in the grindstone. Wear is induced and machining becomes insufficient.

  An object of the present invention is to improve the followability to the radius of curvature R of the crowning in the crowning process. In other words, it is an object to provide a technique capable of accurately and reliably processing with a sufficient drop amount (crowning amount) even for crowning with a very small radius of curvature R.

  The present invention solves the problem by adopting a link device in the grindstone rocking portion of the through-feed superfinishing machine and making the rocking motion locus of the grindstone substantially arc-shaped.

  That is, the present invention uses a through-feed superfinishing machine, presses a grindstone against a work conveyed by a feed roller, and reciprocates the grindstone to perform crowning on the end of the work. In the above, the grindstone is fixed to a free node of a link device, and the grindstone is swung in a plane in which the work draws a movement trajectory.

  The link device is specifically a double lever mechanism. That is, of the four-node rotation mechanism in which all four nodes are connected by a rotation pair, the two longest nodes are the lever nodes, the shortest node is the free node, and the node opposite to the free node is the fixed node. The lever node oscillates around the rotating pair with the fixed node, and the free node draws an arc-shaped movement along with it. A grindstone holder is attached to the free node, and the free node is reciprocated by a driving device.

By setting the length of the fixed joint and the length of the lever joint so that the orthogonal axis passing through the center of the free joint and the normal to the movement trajectory of the workpiece coincide with each other when the swing displacement is maximum The grindstone can be efficiently brought into contact with the workpiece.
Further, as the distance from the neutral position increases, the grindstone holder moves away from the workpiece, but the movement is canceled as follows. That is, the grindstone is held so as to be movable in the normal direction of the workpiece trajectory (arc of curvature radius R) in the grindstone holder and is always pressurized during processing, so that the grindstone holder swings. However, the grindstone is always pressed against the workpiece.
In this manner, the rocking locus of the grindstone can be made substantially coincident with the movement locus of the workpiece, so that machining can be performed while the grindstone and the workpiece are always in contact with each other at a constant pressure.

  According to the present invention, the followability to the radius of curvature R of the crowning is improved. By adopting a link device and oscillating with the movement path of the grindstone accurately following the movement path of the workpiece, the radius of curvature of the workpiece end, which was difficult with conventional through-feed superfinishing, is small and deep drop amount It is possible to reliably perform the crowning process with high accuracy.

It is a partially broken front view of a processing apparatus. It is II-II sectional drawing of FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is a diagram of a link device portion. It is the V section enlarged view of Drawing 4, and shows a contact part of a grindstone and a work typically. It is the elements on larger scale of FIG. It is the elements on larger scale of FIG.

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

As shown in FIGS. 1 and 2, the processing apparatus includes a grindstone holder 10, an air cylinder 20, and a link device 30.
The grindstone S is held by the grindstone holder 10, the grindstone S is pressed against the workpiece W by the air cylinder 20, and the grindstone S is swung in this state to perform super finishing. In order to oscillate the grindstone S, the link device 30 is used, the grindstone is attached to the free node D of the link device 30, and the free node D is reciprocated. As the reciprocating drive device, an eccentric cam, a crank mechanism, or other appropriate mechanism can be selected and employed. FIG. 1 shows an example in which an eccentric cam 32 is employed.
Here, the moving amount of the grindstone S is about ± 0.5 mm and the amplitude is about 1 mm, but is exaggerated in the drawing.

The workpiece S is conveyed while rotating by the pair of feed rolls having the through feed angle described above. Then, as shown in FIG. 1, the movement trajectory of the workpiece W, strictly speaking, the movement trajectory of the outer diameter surface of the workpiece W is set to be an arc having a curvature radius equal to the curvature radius R of the crowning.

As the grindstone S, a plate-shaped stick grindstone can be used. The working surface of the grindstone S, that is, the surface in contact with the workpiece W, is formed in the same arc shape as the movement locus of the workpiece W. The grindstone holder 10 houses a grindstone clamp 14. As can be seen from FIG. 2, the grindstone clamp 14 has a slit 16, and the upper portion of the plate-shaped grindstone S is inserted and held in the slit 16.
Further, as can be seen from FIG. 3, a protrusion 18 is formed on the back surface of the grindstone clamp 14. The protrusion 18 extends in the vertical direction of FIGS. 1 and 2 and perpendicular to the paper surface of FIG.

Looking at the cross section (FIG. 3), both the inner wall surface of the grindstone holder 10 and the outer wall surface of the grindstone clamp 14 are rectangular, with the upper and lower sides being long sides and the left and right sides being short sides. A longitudinal groove 12 is formed on the inner wall surface corresponding to the long side located on the upper side in FIG. 3, and this longitudinal groove 12 receives the projection 18 of the grindstone clamp 14 described above. The long side on the lower side of FIG. 3 is open leaving an area near the short side.

The inner wall surface on the long side of the grindstone holder 10 is in contact with the outer wall surface of the grindstone clamp 14 and serves as a guide surface when the grindstone clamp 14 slides. Thus, since the grindstone clamp 14 is guided by the grindstone holder 10, it can move only in one direction, that is, in the vertical direction in FIGS. 1 and 2, and in the direction perpendicular to the paper surface in FIG.

The grindstone clamp 14 receives the action of the piston rod 22 of the air cylinder 20 through the cylinder block 24. That is, when the piston rod 22 advances, the grindstone clamp 14 is pushed through the cylinder block 24, and the grindstone S is pushed out toward the workpiece W. In the case of the embodiment, the workpiece W is positioned below the grindstone S, and the grindstone S is pushed down and pressed against the workpiece W. Therefore, the air cylinder 20 constitutes a pressurizing device for pressing the grindstone S against the workpiece W.

The cylinder block 24 is fixed to the tip of the piston rod. As can be seen from FIG. 1, the lower surface of the cylinder block 24 is a concave surface, and the upper surface of the grindstone clamp 14 in contact therewith is a convex surface. These convex and concave surfaces have the same radius of curvature. Further, as indicated by an imaginary line in FIG. 1, a liquid passage hole for supplying a machining fluid is provided inside the cylinder block 24. The fluid passage hole is opened on the lower surface of the cylinder block 24, and the machining fluid supplied from the fluid passage hole lubricates the convex surface of the grindstone clamp 14 and the concave surface of the cylinder block 24.

The grindstone clamp 14 is pushed down by the advancement of the piston rod 22 of the air cylinder 20. At this time, the grindstone clamp 14 can move only in one direction by the guide function by the grindstone holder 10 described above. In addition to housing the grindstone clamp 14 having the same rectangular cross section in the grindstone holder 10 having the rectangular cross section, the projection 18 of the grindstone clamp 14 and the vertical groove 12 of the grindstone holder 10 are fitted together, so that only the above-mentioned guide function is provided. In addition, an effect of maintaining a stable posture of the grindstone clamp 14 is obtained.

  Specifically, the link device 30 is a lever mechanism of a four-bar rotation mechanism. That is, as shown in FIG. 4, a four-node rotation mechanism in which all four nodes A, B, C, and D are connected by a rotation pair, and nodes A and B are used as levers, and the shortest node D is a free node. And the node C that is the opposite side of the shortest node D is a fixed node. Lever nodes A and B are equal in length and are the longest nodes. The fixed section C is shorter than the lever sections A and B. The pair a, b, a ′, b ′ employs a rolling bearing or a sliding bearing in order to realize a rotating pair with less resistance.

When the link device 30 moves the free node D, the lever nodes A and B swing. That is, the lever node A swings about the even number a, and the lever node B swings about the pair b. The free node D forms a rotational pair with the free end a ′ of the lever A at one end, and forms a rotational pair with the free end b ′ of the lever B at the other end. Therefore, when the lever nodes A and B swing, the free node D draws an arc-shaped movement locus. In FIG. 4, the neutral position of the link device 30 is indicated by a solid line, and the state in which the levers A and B are swung to the right side and the left side is indicated by broken lines.

4 is an enlarged view of the circled portion of FIG. The action surface of the grindstone S when the link device 30 is in the neutral position is indicated by a solid line, and the action surface of the grindstone S when moved to the right is indicated by a broken line. A one-dot chain line indicates a work outer diameter surface finished by the grindstone S. As described above, the workpiece outer diameter surface is an arc surface having a radius of curvature equal to the radius of curvature R of the crowning.

The pair a of the lever node A and the pair b of the lever node B are provided on the leg portion 28 of the bracket 26. The pair a ′ of the lever A and the pair b ′ of the lever B are provided in the grindstone holder 10. Therefore, the movement trajectory of the free node D described above is also the movement trajectory of the grindstone holder 10 and also the movement trajectory of the grindstone S. The bracket 26 is fixed to a frame or other stationary member of the processing apparatus.

FIG. 6 is an enlarged view of the grindstone holder 10 portion. Here, only the amplitude on one side, that is, the state where the levers A and B swing from the neutral position to the right side in the figure is shown. The solid line is in the neutral position, and the two-dot chain line is in the swinging state. FIG. 7 is a partially enlarged view of FIG. A solid line indicates a neutral position, and a two-dot chain line indicates a swinging state. In these drawings, the arrow x indicates the moving direction of the grindstone holder 10 during swinging, and the arrow y indicates the moving direction of the grindstone clamp 14 and the grindstone S that are pressurized from above.

When the entire grindstone holder 10 is swung by the rotation of the eccentric cam 32 (FIG. 1), the grindstone holder 10 moves in the direction indicated by the arrow x by the action of the link device 30. When the grindstone holder 10 moves in the direction of the arrow x, the working surface of the grindstone S moves away from the work W, but the grindstone S is pressed against the work W because the grindstone clamp 14 is pressurized by the air cylinder 20. At this time, since the grindstone clamp 14 is guided by the grindstone holder 10 and moves only in the direction of the arrow y, the grindstone S always performs (substantially) arc motion while contacting the workpiece W.

The rocking part is basically only the grindstone S, the grindstone clamp 14, the grindstone holder 10, and the piston rod 22, and the mass element such as the main body of the air cylinder 20 does not rock, so the moment of inertia is extremely small and the oscillation frequency is high. Can also follow, and vibration can be suppressed.

Further, the resistance when the grindstone holder 10 swings mainly includes the sliding resistance between the convex surface of the grindstone clamp 14 and the concave surface of the cylinder block 24, and the rolling or sliding resistance of a bearing provided as a turning center. However, the former is alleviated by the lubricating action by the working fluid. The latter is also considerably reduced by the use of a lubricant.

  The effects of the above-described embodiment can be summarized as follows.

  In the embodiment, the grindstone S is fixed to the free node D of the link device 30, and the grindstone S is swung in a plane in which the workpiece W draws a movement trajectory. The link device 30 is a two-lever mechanism of the four-bar rotation mechanism, and has two lever nodes A and B, a fixed node C, and a free node D, all connected by a rotating pair. When the grindstone S is attached to the free node D and the free node D is reciprocated, the lever nodes A and B swing around the rotating pairs a and b, respectively, and the grindstone SS reciprocates along an arc-shaped trajectory. To do.

A driving device 32 for reciprocating the free node D is provided. By adopting a link device in which the free node D draws an arcuate movement trajectory, any drive device for reciprocating the free node D can be selected from the eccentric cam 32, crank mechanism and other existing actuators. Can be selected and used.

It has a pressurizing device 20 for pressing the grindstone S against the workpiece W, the grindstone holder 10 constitutes a free node D, and the grindstone clamp 14 that holds the grindstone S can be moved relative to the grindstone holder 10. The grindstone clamp 14 is pushed by the pressurizing device 20. Thereby, the grindstone clamp 14 can be relatively moved while the grindstone holder 10 is swung, and the grindstone S can be pressed against the workpiece W.

The fixed joint C is constituted by the bracket 26 fixed to the stationary member, and the pressurizing device 20 is fixed to the bracket 26, so that the pressurizing device 20 having a large mass does not swing, so that the moment of inertia of the swing is extremely small. . Therefore, it is possible to follow a high oscillation frequency. It is also advantageous from the viewpoint of vibration suppression.

By storing the grindstone clamp 14 having the outer wall surface having the rectangular cross section in the grindstone holder 10 having the inner wall surface having the rectangular cross section, the grindstone clamp 14 can be moved only in one direction (guide function). Further, by making the one direction coincide with the normal direction with respect to the arcuate movement trajectory of the free node D, the grindstone S is pushed out in the normal direction even when the grindstone holder 10 swings away from the neutral position. It can always be pressed against the workpiece W.

The projection 18 provided on the outer wall surface of the grindstone clamp 14 is fitted in the groove 12 provided on the inner wall surface of the grindstone holder 10, so that the stable posture of the grindstone clamp and thus the grindstone is maintained together with the guide function. Can be made.

  As described above, the embodiment of the present invention has been described by taking as an example the case where the roller for a rolling bearing is a workpiece. However, the present invention is not limited to the embodiment illustrated and described herein, and is within the scope of the claims. Needless to say, various modifications can be made without departing.

  For example, although the case where the number of the grindstone holders is single is illustrated in FIG. 2, a plurality of grindstone holders can be provided in one link device. Further, a plurality of the above-described mechanisms can be provided in one facility. That is, it can also be set as a multiple-type crowning processing apparatus such as double or triple.

  In addition, although a roller of a rolling bearing has been given as a representative example of a workpiece (workpiece), it can also be applied to a roller for linear motion guide, a bearing race, and a cam follower.

DESCRIPTION OF SYMBOLS 10 Grinding wheel holder 12 Vertical groove 14 Grinding wheel clamp 16 Slit 18 Protrusion 20 Air cylinder (pressurizing device)
22 Piston rod 24 Cylinder block 26 Bracket 28 Leg 30 Link device A, B Lever joint C Fixed joint D Free joint 32 Eccentric cam (drive device)
S Whetstone W Workpiece

Claims (9)

Using a through-feed superfinishing machine, pressing a grindstone against a work conveyed by a feed roller, and reciprocating the grindstone to perform crowning on the end of the work,
The grindstone is fixed to a free node of a link device, and the grindstone is swung in a plane in which the work draws a movement trajectory,
When the displacement amount of the swing is maximum, the length of the fixed node and the length of the lever node of the link device so that the orthogonal axis passing through the center of the free node coincides with the normal line of the movement locus of the workpiece. Set
A crowning method, wherein the grindstone is held so as to be movable in a normal direction of a movement trajectory of the workpiece in a grindstone holder constituting the free node, and is always pressurized toward the workpiece during machining. Using a through-feed superfinishing machine, pressing a grindstone against a work conveyed by a feed roller, and reciprocating the grindstone to perform crowning on the end of the work,
A crowning apparatus in which the grindstone is fixed to a free node of a link device, and the grindstone is swung in a plane in which the work draws a movement trajectory. The link device is a double-lever mechanism having two levers, a fixed node, and a free node, all connected by a rotating pair.
The length of the fixed node and the length of the lever are set so that the orthogonal axis passing through the center of the free node and the normal to the movement trajectory of the workpiece coincide with each other when the displacement amount of the swing is maximum. 2. Crowning machine. Having a grindstone holder for holding the grindstone so as to be movable in the normal direction of the movement trajectory of the workpiece, and constituting the free node with the grindstone holder;
The crowning apparatus according to claim 3, further comprising a pressurizing device for pressurizing the grindstone toward the workpiece. 5. A crowning apparatus according to claim 2, further comprising a driving device for reciprocating the free node. The crowning processing apparatus according to claim 2, 3, or 4, further comprising a grindstone clamp housed in the grindstone holder and capable of moving relative to the grindstone holder, wherein the grindstone clamp is pushed by the pressurizing device. The crowning processing apparatus according to claim 5 or 6, wherein a fixing node is constituted by a bracket fixed to a stationary member, and the pressurizing device is fixed to the bracket. The crowning apparatus according to claim 5, 6 or 7, wherein the grindstone clamp has an outer wall surface having a rectangular cross section, the grindstone holder has an inner wall surface having a rectangular cross section, and the grindstone clamp is accommodated in the grindstone holder. 9. A crowning apparatus according to claim 8, wherein the protrusion provided on the outer wall surface of the grindstone clamp is fitted in a groove provided on the inner wall surface of the grindstone holder.

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