JP5199015B2 - Cam surface grinding method - Google Patents

Description

  The present invention relates to a cam surface grinding method for grinding a cam surface formed on an outer peripheral surface of a cam, and particularly to a cam surface grinding method having a concave portion and a convex portion.

  In general, when the cam surface on the outer periphery of the cam is ground with a rotating grindstone that rotates on an axis parallel to the cam rotation axis, the rotating grindstone is rotated while the cam is rotated about the rotation axis. Advancing and retreating in the direction intersecting the axis, that is, in the radial direction of the cam. In such a cam surface grinding method, when a convex portion and a concave portion are formed on the cam surface, a small-diameter rotating grindstone that can contact the concave portion at one location, that is, the curvature of the outer peripheral surface is concave. It is necessary to use a rotating grindstone with a curvature equal to or less than the curvature of the part. Conversely, when a large-diameter rotating grindstone whose outer peripheral surface curvature exceeds that of the concave portion is used, there are two contact portions between the concave portion and the rotating grindstone, and grinding cannot be performed.

  However, when a small-diameter rotary grindstone is used, the axis of the rotary grindstone approaches the cam side. There is a possibility that a motor for driving the rotating grindstone, a grindstone support for supporting the rotating grindstone, and the like interfere with a shaft for supporting the cam. In addition, when a plurality of cams are formed on the workpiece at intervals in the axial direction, the wheel head or the like may interfere with other cams other than the cam being ground.

  In order to solve such a problem, Patent Document 1 discloses a grinding method in which a rotating grindstone having a tapered grinding surface is used and the axis of the rotating grindstone is inclined with respect to the axis of the cam. . According to this grinding method, since the axis of the rotating grindstone can be moved away from the axis of the cam, the above-described interference problem can be avoided. However, in this grinding method, since the outer peripheral surface of the rotating grindstone is tapered, accurate grinding cannot be expected only by advancing and retracting the rotating grindstone according to the irregularities of the cam surface. That is, the non-circular portion of the cam surface comes into contact with the grinding surface of the rotating wheel from an oblique direction, but the grinding surface of the rotating wheel has a tapered shape. The ridge line in contact with the cam is not parallel to the cam axis.

  In order to cope with such a problem, for example, a cam surface grinding method as disclosed in Patent Document 2 has been proposed. In this conventional method, the rotating grindstone having the tapered grinding surface is used as described above, and the rotating grindstone is camped in a state where the rotating axis of the rotating grindstone is inclined at a predetermined angle with respect to the rotating axis of the cam. It is made to move forward and backward according to the unevenness of the cam surface.

And in the conventional method of this patent document 2, the rotary grindstone is reciprocated in the direction orthogonal to the forward / backward movement direction in relation to the forward / backward movement position of the rotary grindstone. For this reason, the position of the ridge line is moved in a direction orthogonal to the advancing / retreating movement direction of the rotating grindstone, and an attempt is made to suppress occurrence of grinding unevenness and grinding residue.
JP-A-8-243906 JP 2000-510771 A

  However, Patent Document 2 only describes reciprocating the rotating grindstone in a direction orthogonal to the advancing / retreating movement direction so as to match the rotational position of the cam and the advancing / retreating movement position of the rotating grindstone. The above detailed operation is not disclosed. Incidentally, when the inventors of the present invention actually tested the grinding operation of the above-described grinding method of Patent Document 2, the cam was continuously rotated in one direction or moved in a direction perpendicular to the forward / backward direction. It has been found that it is difficult to perform grinding of the cam surface having the concave portion and the convex portion only by making them.

  The present invention has been made paying attention to such problems existing in the prior art. An object of the present invention is to provide a cam surface grinding method capable of accurately grinding a cam surface having a concave portion and a convex portion.

  In order to achieve the above object, the present invention provides a grinding surface on the outer periphery of a rotating grindstone while rotating a cam in which a concave portion and a convex portion are formed on the cam surface of the outer peripheral surface around its rotation axis. In the cam surface grinding method in which the cam surface is ground at a single point in contact with the cam surface, the rotating grindstone having a tapered grinding surface is used and passes through the rotation axis of the cam. In the first plane, the rotational axis of the rotary grindstone is tilted with respect to the rotational axis of the cam so as to have the same tilt angle as the tilt angle of the grinding surface, and in this tilted state, the rotary grindstone is moved to the first plane. And a reciprocating movement in a direction perpendicular to the rotation axis of the cam in a second plane perpendicular to the first plane, and a concave portion of the cam surface. When grinding It is characterized in that in opposite directions the direction of movement of the grinding wheel with respect to the rotation direction and the movement direction when grinding a convex portion of the cam surface in the rotational direction and the second plane of.

  Therefore, in this invention, since the rotation axis of the rotating grindstone is inclined with respect to the axis of the cam, the grindstone table or the like supporting the rotating grindstone does not interfere with the main shaft or the like supporting the cam, and the concave and convex portions. It is possible to easily grind the cam surface having Moreover, since the rotation direction of the cam is reversed and the reciprocating direction of the rotating grindstone is changed between the concave portion and the convex portion on the cam surface, the cam surface can be appropriately ground.

  As described above, according to the present invention, it is possible to accurately grind the cam surface having the concave portion and the convex portion.

Hereinafter, an embodiment of a cam surface grinding apparatus embodying the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, a work support 12 is disposed on the upper surface of the base 11 so as to be movable in the left-right direction (Z-axis direction). A spindle stock 13 is disposed on the upper surface of one side of the work support base 12, and a spindle 14 is rotatably supported by the spindle stock 13. A tailstock 15 is arranged on the other upper surface of the work support 12 so as to correspond to the headstock 13. A workpiece W such as a camshaft is detachably supported between the spindle 14 of the spindle stock 13 and the tailstock 15 so as to be positioned on the Z axis.

  As shown in FIGS. 1 and 2, a plurality (or a single) of cams C are integrally formed on the workpiece W at intervals in the axial direction. As shown in FIG. 3, a cam surface F is formed on the outer peripheral surface of each cam C. On the cam surface F of the cam C, three convex portions Fa1, Fa2, Fa3 and concave portions Fb1, Fb2, Fb3 are formed alternately at predetermined intervals.

  As shown in FIGS. 1 and 2, a work rotation motor 16 that can rotate forward and reverse is mounted on the head stock 13. Then, in a state where the workpiece W is supported between the spindle 14 of the spindle stock 13 and the tailstock 15, the spindle 14 is rotated by the motor 16, whereby the workpiece W having a plurality of cams C is obtained. It is rotated at a low speed around a rotation axis L1 extending in the Z-axis direction. An encoder 17 for detecting the rotation angle of the motor 16, that is, the rotation position, is attached to the outer end portion of the motor 16.

  As shown in FIGS. 1 and 2, corresponding to the work support 12, a moving table 18 is placed on the base 11 through a pair of guide rails 19 in the front-rear direction perpendicular to the rotation axis L <b> 1 of the work W It is arranged to be movable in the (X-axis direction). On the upper surface of the movable table 18, the column 20 is erected in a state of being inclined at a predetermined angle with respect to the rotation axis L <b> 1 of the workpiece W. A grindstone base 21 is supported on the front surface of the column 20 through a pair of guide rails 22 so as to be movable in the vertical direction (Y-axis direction) perpendicular to the moving direction of the moving base 18.

  As shown in FIGS. 1 and 2, the grinding wheel base 21 has a predetermined axis with respect to the rotation axis L <b> 1 (Z-axis direction) of the workpiece W in a first plane in which the grinding wheel shaft 23 passes through the rotation axis of the workpiece W. It is supported so as to be rotatable about a rotation axis L2 inclined at an angle α. A rotating grindstone 24 is attached to the end of the grindstone shaft 23, and a grinding surface 24 a made of a tapered surface is formed on the outer peripheral surface of the rotating grindstone 24. The angle of the tapered surface of the grinding surface 24a, that is, the angle of the grinding surface 24a is inclined at the same angle α as the angle α with respect to the rotation axis L2 of the grinding wheel shaft 23. A grinding wheel rotating motor 25 is mounted on the grinding wheel base 21. Then, when the grindstone shaft 23 is rotated by the motor 25, the rotating grindstone 24 is rotated in one direction at a high speed.

  As shown in FIG. 1, a grindstone X-axis direction moving motor 26 made of a servo motor or the like capable of rotating in the forward and reverse directions is mounted on the rear portion of the base 11. Then, the moving table 18 is moved in the first plane by the motor 26 via the feed screw 27, so that the rotating grindstone 24 intersects the rotation axis L1 of the cam C on the workpiece W (X axis). Direction), that is, the cam C is moved back and forth in the radial direction. An encoder 28 for detecting the rotation angle of the motor 26 is attached to the outer end portion of the motor 26.

  As shown in FIGS. 1 and 2, a grindstone Y-axis direction moving motor 29 made of a servomotor or the like capable of rotating in the forward and reverse directions is mounted on the rear portion of the column 20. Then, when the grindstone table 21 is moved by the motor 29 via the feed screw 30, the rotary grindstone 24 is vertically moved in the second plane perpendicular to the first plane (Y It is reciprocated in the axial direction. An encoder 31 for detecting the rotation angle of the motor 29 is attached to the outer end portion of the motor 29.

Next, the circuit configuration of the cam surface grinding apparatus configured as described above will be described.
As shown in FIG. 4, the control device 35 constitutes a control means for controlling the operation of the entire cam surface grinding device. The storage unit 36 stores a control program for controlling the operation of each part of the cam surface grinding apparatus, a machining program for machining the cam surface of various cams, various data necessary for executing the machining program, and the like. Yes.

  The control device 35 receives detection signals from the encoders 17, 28, and 31 for the motors, and receives an operation signal from the operation unit 37. The operation unit 37 includes an operation panel including various operation switches for instructing the operation of the cam surface grinding apparatus, operation keys for inputting machining data, and the like. In addition, the control device 35 outputs operation and stop signals to the motors 16, 25, 26, and 29 and outputs a display signal to the display unit 38. The display unit 38 includes a display for displaying machining data and the like when inputting machining data or grinding the cam surface.

  When the cam surface F of the cam C is ground according to the machining program stored in the storage unit 36, the control device 35, based on the detection signals from the encoders 17, 28, 31, each motor 16, 26, 29 is operated to control the rotation of the cam C, the reciprocating movement of the rotating grindstone 24 in the X-axis direction according to the uneven shape of the cam surface F, and the reciprocating movement of the rotating grindstone 24 in the Y-axis direction. The motor 26 for rotating the rotating grindstone 24 is continuously rotated at least when the cam surface F of the cam C is ground.

  As shown in FIG. 3, when the cam C having the convex portions Fa1 to Fa3 and the concave portions Fb1 to Fb3 on the cam surface F is ground, the control device 35 rotates the rotating grindstone 24 in one direction at a high speed. The cam C is rotated at a low speed in one direction or the other direction at a predetermined timing described later. Then, according to the shape change of the cam surface F accompanying the rotation of the cam C, that is, according to the irregularities of the cam surface F, the rotating grindstone 24 intersects the rotation axis L1 of the cam C in the first plane as will be described later. It moves forward and backward in the X axis direction, that is, in the radial direction of the cam C. At the same time, the rotary grindstone 24 is reciprocated in the Y-axis direction orthogonal to the forward / backward movement direction in the second plane.

Next, a method for grinding the cam surface by the cam surface grinding apparatus configured as described above will be described.
As shown in FIGS. 1 and 2, when the operation of the apparatus is started in a state where the workpiece W is mounted between the spindle 14 and the tailstock 15 of the spindle stock 13, the workpiece rotation motor 16 The cam C is rotated at a low speed around the rotation axis L1. At the same time, the grindstone rotating motor 25 rotates the rotating grindstone 24 at a high speed in one direction around the rotation axis L2 inclined at a predetermined angle α with respect to the rotation axis L1 of the cam C. Then, the grindstone X-axis direction moving motor 26 moves the rotating grindstone 24 closer to the cam surface F of the cam C along the X-axis direction, and as shown in FIG. Is brought into contact with the grinding start position P1 on the cam surface F.

  In the following description of the operation, the grinding start position P1 on the cam surface F is set at the boundary between the first convex portion Fa1 and the third concave portion Fb3 of the cam surface F, and the grinding starts. It is described that the grinding of the cam surface F proceeds from the position P1 toward the first convex portion Fa1 side. However, the grinding start position on the cam surface F may be anywhere, but the grinding of the cam C is ended when the cam C makes one rotation.

  Now, when grinding from the grinding start position P1 of the cam surface F toward the first convex portion Fa1, the cam C is rotated in the direction D1, as shown in FIG. The rotary grindstone 24 is moved backward in the X1 direction away from the axis L1 of the cam C along the X-axis direction by the grindstone X-axis direction moving motor 26 and is also moved in the X-axis direction by the grindstone Y-axis direction moving motor 29. Is moved upward in the Y1 direction along the Y-axis direction orthogonal to the Y direction. Thereby, the 1st convex part Fa1 of the cam surface F is ground in order from the grinding start position P1.

  Thereafter, as shown in FIG. 6, when the grinding of the first convex portion Fa1 proceeds to the apex position P2 of the first convex portion Fa1, the movement of the rotary grindstone 24 in the Y1 direction is continued. The movement of the rotating grindstone 24 in the X-axis direction is changed, and the rotating grindstone 24 is moved forward in the X2 direction approaching the axis L1 of the cam C. Thereby, the remaining portion of the first convex portion Fa1 is ground. And as shown in FIG. 7, when grinding progresses to the boundary position P3 of 1st convex part Fa1 and 1st concave part Fb1, grinding of 1st convex part Fa1 is complete | finished. That is, while the cam C is rotated by the rotation angle R1 in the direction D1 from the angular position shown in FIG. 5 to the angular position shown in FIG. 7, the grinding of the first convex portion Fa1 is completed.

  Subsequently, in the state shown in FIG. 7, the rotation direction of the cam C is reversed, and the cam C is rotated in the direction D2 opposite to the rotation direction D1 of the first convex portion Fa1. At the same time, the movement of the rotating grindstone 24 in the Y-axis direction is changed, and the rotating grindstone 24 is moved downward in the Y2 direction. Accordingly, the first concave portion Fb1 is ground in order from the boundary position P3 between the first convex portion Fa1 and the first concave portion Fb1.

  Thereafter, as shown in FIG. 8, when the grinding of the first concave portion Fb1 proceeds to the intermediate position P4 of the first concave portion Fb1, the rotation of the rotating grindstone 24 in the Y2 direction is continued. The movement of the grindstone 24 in the X-axis direction is changed, and the rotary grindstone 24 is moved backward in the X1 direction. Thereby, the remaining portion of the first concave portion Fb1 is ground. Then, as shown in FIG. 9, when the grinding proceeds to the boundary position P5 between the first concave portion Fb1 and the second convex portion Fa2, the grinding of the first concave portion Fb1 is completed. That is, the grinding of the first concave portion Fb1 is completed while the cam C is rotated by the rotation angle R2 in the direction D2 from the angular position shown in FIG. 7 to the angular position shown in FIG.

  In this case, the rotation angle R1 when grinding the first convex portion Fa1 is larger than the rotation angle R2 when grinding the first concave portion Fb1. For this reason, the cam C is rotated in the direction D1 by the rotation angle R1-R2 as a total while the continuous first convex portion Fa1 and first concave portion Fb1 are ground.

  In the state shown in FIG. 9, the rotation direction of the cam C is reversed, and the cam C is rotated in the direction D1 opposite to the rotation direction D2 of the first concave portion Fb1. At the same time, the movement of the rotating grindstone 24 in the Y-axis direction is changed, and the rotating grindstone 24 is moved upward in the Y1 direction. Accordingly, the second convex portion Fa2 is ground in order from the boundary position P5 between the first concave portion Fb1 and the second convex portion Fa2.

  Thereafter, at positions P6, P7, P8, and P9 on the cam surface F, operations similar to the positions P1, P2, P3, P4, and P5 on the cam surface F shown in FIGS. The grinding of the second convex portion Fa2 and the second concave portion Fb2 is performed in order. Further, the third convex portion Fa3 and the third concave portion Fb3 are similarly ground. Then, the cam C makes one rotation from the initial state, and as shown in FIG. 5, the grinding progresses to the boundary position between the third concave portion Fb3 and the first convex portion Fa1, that is, the grinding start position P1. At this time, the grinding of the entire cam surface F is completed.

The cam surface grinding method of this embodiment operated as described above has the following effects.
(1) When the cam surface F having the convex portions Fa1 to Fa3 and the concave portions Fb1 to Fb3 is ground, the rotational axis L2 of the rotating grindstone 24 is inclined with respect to the rotational axis L1 of the cam C. Accordingly, it is possible to prevent the grindstone shaft 23 of the rotating grindstone 24 from interfering with other members such as the cam C which is not ground.

  (2) When grinding the cam surface F having the convex portions Fa1 to Fa3 and the concave portions Fb1 to Fb3 as described above, the rotational axis L2 of the rotating grindstone 24 is inclined with respect to the rotational axis L1 of the cam C. The rotary grindstone 24 is moved back and forth in the direction (X-axis direction) intersecting the rotation axis L1 of the cam C, and reciprocated in the direction (Y-axis direction) perpendicular to the forward / backward movement direction. Therefore, even if the ridge line of the outer peripheral grinding surface 24a of the rotating grindstone 24 that contacts the cam surface F is not parallel to the direction of the rotational axis L1 of the cam C, the outer peripheral grinding surface 24a becomes a surface centered on the rotational axis L1. Can be ground.

  (3) When the concave portions Fb1 to Fb3 of the cam surface F are ground and when the convex portions Fa1 to Fa3 are ground, that is, when the concave and convex directions of the cam surface F are different, the rotation direction of the cam C To reverse. Therefore, the cam surface F can be accurately ground according to the uneven shape of the cam surface.

  (4) In grinding of the cam surface F, the cam surface F can be accurately ground only by moving the rotating grindstone 24 in the X and Y directions simultaneously with the rotation of the cam C, and the axial dimension of the rotating grindstone is short. Can be used. Incidentally, in order to accurately grind the cam surface F, it is conceivable to move the rotating grindstone 24 in the axial direction of the cam C during grinding, but in this way, the rotating grindstone moves from the cam surface F to its axial direction. It is necessary to use one having a long axial dimension so that it does not go outside. If a rotating grindstone having an axial dimension shorter than the cam surface F is used, it is necessary to rotate the cam C two or more times, and the time required for grinding becomes longer.

(Example of change)
In addition, this embodiment can also be changed and embodied as follows.
-In the said embodiment, although it implements about the grinding | polishing of the cam surface F which provided the three convex-shaped parts Fa1-Fa3 and the concave-shaped parts Fb1-Fb3, one each, two each or each on a cam surface Carrying out grinding of a cam surface provided with a plurality of convex portions and concave portions of four or more.

  -As the rotating grindstone 24, one whose curvature of the grinding surface 24a is equal to the curvature of the concave portions Fb1 to Fb3 of the cam surface F should be used.

The top view which shows one Embodiment of the cam surface grinding apparatus which actualized this invention. The principal part front view of the cam surface grinding apparatus of FIG. The partial expanded sectional view in the 3-3 line of FIG. The block diagram which shows the circuit structure of a cam surface grinding apparatus. The figure which shows the grinding operation state of the cam surface by the cam surface grinding apparatus. The figure which shows the grinding operation state of the cam surface following FIG. The figure which shows the grinding operation state of the cam surface following FIG. The figure which shows the grinding operation state of the cam surface following FIG. The figure which shows the grinding operation state of the cam surface following FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 13 ... Main shaft base, 14 ... Main shaft, 15 ... Tailstock, 16 ... Motor for work rotation, 18 ... Moving table, 21 ... Grinding wheel base, 23 ... Grinding wheel shaft, 24 ... Rotary grinding wheel, 24a ... Outer peripheral grinding surface, 25 ... Grinding wheel rotating motor, 26: grinding wheel X-axis direction moving motor, 29: grinding wheel Y-axis direction moving motor, 35 ... control device, 36 ... storage unit, W ... work, C ... cam, F ... cam surface, Fa1 Fa3 ... convex portion, Fb1 to Fb3 ... concave portion, L1 ... rotation axis of the cam, L2 ... rotation axis of the rotating grindstone, α ... inclination angle, D1, D2 ... rotation direction of the cam.

Claims (1)

A cam having a concave portion and a convex portion formed on the cam surface of the outer peripheral surface is rotated around its rotation axis, and the outer peripheral grinding surface of the rotating grindstone is brought into contact with the cam surface at one location, and the cam In the grinding method of the cam surface that grinds the surface,
As the rotating grindstone, a taper-shaped grinding surface is used,
In a first plane passing through the rotation axis of the cam, the rotation axis of the rotary grindstone is inclined with respect to the rotation axis of the cam so as to have the same inclination angle as the inclination angle of the grinding surface,
In this inclined state, the rotating grindstone is moved back and forth in the direction intersecting the cam rotation axis in the first plane, and is orthogonal to the cam rotation axis in the second plane orthogonal to the first plane. Reciprocate in the direction,
The rotational direction of the cam when grinding the concave portion of the cam surface and the moving direction of the rotating grindstone in the second surface are opposite to the rotational direction and the moving direction when grinding the convex portion of the cam surface, respectively. A method for grinding a cam surface.

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