JP2007320008A - Cam grinder and cam grinding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cam grinder, grinding the recessed part of a cam without minding interference of a wheel spindle stock and a work, and increasing the peripheral speed of the grinding wheel to efficiently grind a cam having a recessed part. <P>SOLUTION: This cam grinder includes: a spindle stock 1 for driving a work W having a cam part Wa in rotation; the wheel spindle stock 3 for driving the grinding wheel 2 in rotation; and moving means 4, 5, 11, 15 for relatively moving the work and the grinding wheel in the direction where the grinding wheel 2 approaches and separates from the work W and in the direction parallel to the rotating shaft 7 of the work W, wherein the wheel spindle stock 3 is provided with a rotating shaft 6 of the grinding wheel at right-angled to the rotating shaft 7 of the work, in the grinding wheel 2, the outer peripheral surface 3 is bulged like a circular arc in the thickness direction of the grinding wheel, and while the work W and the grinding wheel 2 are rotated, the grinding wheel 2 is brought into contact with the outer periphery of the cam part Wa of the work, and the work W and the grinding wheel 2 are relatively moved by the moving means 4, 5 to grind the cam having the recessed part 14 on the outer periphery of the cam part Wa. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cam grinding machine and a cam grinding method for grinding a cam having a recess.

As a cam grinding machine that grinds the cam part of a workpiece such as a camshaft, the spindle has a spindle that rotates the workpiece, and a grinding wheel base that has a grinding wheel that rotates around an axis parallel to the spindle, while rotating the workpiece by the spindle, There is known one that grinds the outer periphery of a cam portion into a desired cam shape by moving a grindstone base in a direction orthogonal to the main shaft in conjunction with the rotation of the main shaft (for example, see Patent Document 1).
In recent years, the cam shape of the cam portion of the camshaft tends to be a gourd shape having a recess. This is because, when the cam shape is a gourd shape, the operation speed of the valve controlled by the cam increases between the open state and the closed state, thereby improving the engine output and fuel consumption.

  In order to grind a cam having a recess, it is necessary to use a small-diameter grinding wheel that can contact the recess. If the diameter of the grinding wheel is reduced, the grinding wheel head may protrude from the outer periphery of the grinding wheel and the grinding wheel table may interfere with other cam parts or tailstocks of the workpiece. In the cam grinder with the parallel to each other, even if the diameter of the grinding wheel is reduced, the diameter is limited to about 100 mm at most, and therefore a concave portion having a radius of curvature smaller than 50 mm (R50) cannot be ground. Also, with a small-diameter grinding wheel, the peripheral speed of the grinding wheel does not increase so much, and the grinding wheel base must be made compact so that it does not protrude from the outer periphery of the small-diameter grinding wheel, and the rigidity of the rotating shaft of the grinding wheel is low. For this reason, it has been impossible to apply a large grinding load by increasing the cutting depth, and it took time to grind.

In order to avoid interference between the grinding wheel platform and the workpiece, there is a method of arranging the grinding wheel platform at an angle with respect to the rotation axis of the workpiece (see, for example, Patent Documents 2 and 3). Therefore, the grinding wheel has a low peripheral speed and the cam grinding takes time. Therefore, in the thing of patent document 2, apart from the angular grinding wheel head which arranged the small diameter grinding wheel diagonally with respect to the axis of rotation of a work, the rough grinding grinding wheel base which arranged the large diameter grinding wheel in parallel with the work was installed, Grinding time is shortened by rough grinding with the large diameter grinding wheel. However, if two grindstone stands are installed in this way, the apparatus becomes large.
JP 2004-188560 A Japanese Patent No. 3644068 JP 2006-35387 A

  In view of the situation described above, the present invention can grind the concave portion of the cam without worrying about the interference between the grinding wheel table and the workpiece, and also has the concave portion efficiently by increasing the peripheral speed of the grinding wheel. An object is to provide a cam grinding machine and a cam grinding method capable of grinding a cam.

  In order to achieve the above object, the cam grinding machine of the present invention includes a spindle stock for rotationally driving a workpiece having a cam portion, a grinding wheel platform for rotationally driving a grinding wheel, and a direction in which the grinding wheel approaches and separates toward the workpiece. And a moving means for moving the workpiece and the grinding wheel relative to each other in a direction parallel to the rotation axis of the workpiece, and the grinding wheel table is provided with the rotation axis of the grinding wheel perpendicular to the rotation axis of the workpiece. The outer peripheral surface bulges in an arc shape in the thickness direction of the grinding wheel, the grinding wheel is brought into contact with the outer circumference of the cam portion of the workpiece while rotating the workpiece and the grinding wheel, and the workpiece and the grinding wheel are moved relative to each other by the moving means. The cam having a concave portion on the outer periphery of the cam portion is ground.

  The cam grinding method of the present invention is a grinding wheel in which the outer periphery of the cam portion of a rotating workpiece rotates around an axis provided at a right angle to the rotation axis of the workpiece and the outer peripheral surface bulges in an arc shape in the grinding wheel thickness direction. The grinding wheel is ground by moving the workpiece and the grinding wheel relative to each other in a direction in which the grinding wheel approaches and separates toward the workpiece and in a direction parallel to the rotation axis of the workpiece. And

  In the cam grinding machine and the cam grinding method of the present invention, the rotational axis of the grinding wheel is provided at a right angle to the rotational axis of the workpiece, and the outer peripheral surface of the grinding wheel is expanded in an arc shape in the grinding wheel thickness direction. Since the concave portion of the cam can be ground by R, the diameter of the grinding wheel can be increased regardless of the R of the concave portion of the cam, and the grinding wheel base and the workpiece do not interfere with each other. Further, it is possible to easily grind the concave portion having a small R, which has been difficult in the past. Furthermore, by using a grinding wheel with a large diameter, the peripheral speed of the grinding wheel can be increased, and the rigidity of the rotating shaft of the grinding wheel can be increased, so it is possible to increase the cutting depth and apply a large grinding load. Thus, the cam having the recess can be efficiently ground. Since it is not necessary to provide two grinding wheel platforms, the apparatus does not become large. By relatively moving the workpiece and the grinding wheel in a direction parallel to the rotation axis of the workpiece, the cam including the recess can be easily ground.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing an embodiment of a cam grinder of the present invention, and FIG. 2 is a side view of the cam grinder. In this cam grinding machine, a work table 10 is provided on the slide base 20 on the front side of the bed 9, and the work table 10 is moved in the left-right (Z) direction by the Z-axis ball screw 11 and the Z-axis servo motor 4. Support is possible. On the work table 10, a headstock 1 and a tailstock 12 are provided, and a workpiece W is detachably attached horizontally between the spindle 1a and the tailstock 12 of the headstock 1 in the horizontal direction. Yes. The rotation axis 7 of the workpiece W coincides with the axis of the main shaft 1a, and the main shaft 1a is rotationally driven by the main shaft servomotor 13 provided on the main shaft 1 so that the work W is rotated counterclockwise in FIG. Rotate with variable speed according to.
The workpiece W is a camshaft and has a plurality of cam portions Wa in the axial direction. As shown in FIG. 3, each cam portion Wa has a base circle portion 18, a lift portion 14, and a cam top portion 19, and the lift portion is a concave portion 14 that is recessed in an arc shape.

  A grindstone bed 3 is provided behind the work table 10 on the bed 9. The grinding wheel base 3 is supported by an X-axis ball screw 15 and an X-axis servo motor 5 so as to be movable in the front-rear (X) direction. The grinding wheel base 3 has a rotary shaft 6 provided in the vertical direction, the grinding wheel 2 is attached to the lower part of the rotary shaft 6, and the upper part of the rotary shaft 6 is connected to a grinding wheel motor 16. Thus, the rotary shaft 6 and the grinding wheel 2 are rotated in one direction. The grinding wheel 2 uses a large-diameter grinding wheel having a diameter of 250 to 350 mm, and the peripheral speed is about 120 to 160 m / sec. Moreover, as shown in FIG. 3, the outer peripheral surface 8 of the grinding wheel 2 bulges in a semicircular shape in the grinding wheel thickness direction. R in the grinding wheel thickness direction of the grinding wheel outer peripheral surface 8 is equal to or less than R of the concave portion 14 of the cam portion of the workpiece W. In addition, as shown in FIGS. 2 and 3, the grinding wheel 2 has a central portion in the thickness direction located at the same height as the rotation shaft 7 of the workpiece W. In this way, the rotating shaft 6 of the grinding wheel 2 is set in the vertical direction perpendicular to the rotating shaft 7 of the workpiece W, and the outer peripheral surface 8 of the grinding wheel 2 is swelled in a semicircular shape in the thickness direction of the grinding wheel. The outer periphery of the vehicle 2 and the outer periphery of the cam portion Wa contact at one point, and the contact surface at the time of cutting becomes a spherical surface.

  The cam grinding machine further includes a control device 17 that controls the rotation of the main shaft servomotor 13, the Z-axis servomotor 4, the X-axis servomotor 5, and the grindstone motor 16. The control device 17 includes a program for controlling the movement of each motor to automatically grind the outer periphery of the cam portion Wa of the workpiece into a predetermined cam shape, and a cam profile corresponding to the final cam shape of the cam portion. Data is stored.

  As shown in FIG. 3, the present cam grinding machine makes a predetermined cut by bringing the outer periphery of the grinding wheel 2 rotating at high speed into contact with the outer periphery of the cam portion Wa of the workpiece, thereby providing the spindle servo motor 13 and the X-axis servo motor. 5 is simultaneously controlled by the control device 17 according to the rotation angle of the workpiece W, and the grindstone table 3 is reciprocated in the front-rear direction according to the rotation angle of the workpiece W based on the cam profile data stored in the control device 17. Thus, a cam having a desired shape can be ground on the outer periphery of the cam portion Wa. In the cam recess 14, the contact area with the grinding wheel 2 is large, and the grinding allowance is larger than the base circle portion 18 and the cam top portion 19. Therefore, the rotational speed of the workpiece W when grinding the recess 14 is The base circle portion 18 and the cam top portion 19 are slower than when grinding. The grinding of the cam portion Wa is performed through a plurality of grinding steps in the order of rough grinding → intermediate finish grinding → finish grinding → spark out while reducing the cutting amount of the grinding wheel 2 with respect to the outer periphery of the cam portion Wa. Such control is the same as that performed by the conventional cam grinding machine disclosed in Patent Document 1 and the like.

In this cam grinding machine, the rotating shaft 6 of the grinding wheel 2 is set in a vertical direction perpendicular to the rotating shaft 7 of the workpiece W. A dent along the circumferential direction R of the grinding wheel 2 is formed on the surface. Therefore, in this cam grinding machine, as shown in FIG. 4, when the grinding wheel 2 is reciprocated back and forth while rotating the workpiece W to grind the cam, the Z-axis servo is controlled by the controller 17 as shown in FIG. By driving the motor 4 and moving the workpiece W to the right or left, the surface of the cam can be ground flat. FIG. 4 shows a case where the workpiece W is ground while moving in the right direction.
More specifically, the workpiece W is moved from the right to the left or the left to the right by the width of the cam portion Wa at a relatively slow speed in each grinding step of rough grinding, intermediate finish grinding, finish grinding, and spark out. During the movement, the work W is rotated a plurality of times (at the same time, the grinding wheel 2 is reciprocated in the front-rear direction in synchronization with the rotation of the work W), and the outer periphery of the cam portion Wa is ground. In order to gradually reduce the cutting amount as the grinding process progresses, the moving speed of the workpiece W may be gradually decreased as the grinding process progresses. It is also possible to adjust the cutting depth only by controlling the above.
As another grinding method, the grinding wheel 2 is reciprocated back and forth in synchronization with the rotation of the workpiece W while rotating the workpiece W relatively slowly, and at the same time the workpiece W is rotated once, the workpiece W is moved to the cam portion Wa. The cam can also be ground by moving it multiple times from right to left and from left to right by the width of.
In the above two grinding methods, the workpiece W may be moved in the left-right direction only during finish grinding and spark-out without moving the workpiece W in the left-right direction in rough grinding and intermediate finish grinding.

  As described above, in this cam grinding machine, the rotary shaft 6 of the grinding wheel 2 is set in the vertical direction perpendicular to the rotary shaft 7 of the workpiece W, and the outer peripheral surface 8 of the grinding wheel 2 is expanded in an arc shape in the thickness direction of the grinding wheel. Since the cam recess 14 can be ground with R in the thickness direction of the grinding wheel, the diameter of the grinding wheel 2 can be increased regardless of the R of the recess 14 of the cam, and the grinding wheel base 3 The cam portion Wa, the headstock 1 and the tailstock 12 do not interfere with each other. In addition, grinding of the small R concave portion 14 which has been difficult in the past can be easily performed. Furthermore, since the peripheral speed of the grinding wheel 2 can be increased by using the grinding wheel 2 having a large diameter, and the rigidity of the rotary shaft 6 of the grinding wheel 2 can be increased, the amount of cutting is increased and a large grinding load is applied. The cam having the recess 14 can be ground efficiently. One grindstone table 3 can perform rough grinding to spark-out of the cam, and it is not necessary to provide two grindstone tables, so that the apparatus does not become large. Further, by performing grinding while moving the grinding wheel base 3 in the left-right direction, the cam including the concave portion 14 can be easily ground without forming a recess due to R in the circumferential direction of the grinding wheel 2 on the surface of the cam.

  The present invention is not limited to the embodiments described above. For example, the work table 10 can be fixedly provided on the bed 9 and the grindstone table 3 can be moved in the left-right direction and the front-rear direction. Alternatively, the grinding wheel rotation shaft 6 may be a horizontal axis, and the grinding wheel base 3 may be moved in the vertical direction so that the grinding wheel 2 approaches and separates toward the workpiece W. The grinding wheel 2 can arbitrarily form R in the thickness direction of the outer peripheral surface 8, and as shown in FIGS. 5 (a) and 5 (b), a smaller R or a larger R than a semicircle whose diameter is the grinding wheel thickness. Can also be supported.

It is a top view which shows one Embodiment of the cam grinding machine of this invention. It is a side view of the cam grinding machine. It is an enlarged side view which shows the state which grinds the cam part of a workpiece | work with a grinding wheel, Comprising: (a) is a state when grinding the lift part (concave part) of a cam part, (b) is a cam part. A state when the base circle portion is being ground, (c) shows a state when the cam top portion of the cam portion is being ground. It is an enlarged plan view which shows the state which is grinding the cam part of a workpiece | work with a grinding wheel. It is a side view which shows other embodiment of the shape of the outer peripheral surface of a grinding wheel.

Explanation of symbols

1 Main spindle base 2 Grinding wheel 3 Grinding wheel base 4 Z-axis servo motor (moving means)
5 Servo motor for X axis (moving means)
6 Rotating shaft of grinding wheel 7 Rotating shaft of workpiece 8 Outer peripheral surface of grinding wheel 9 Bed 10 Work table 11 Z-axis ball screw (moving means)
12 Tailstock 13 Servo motor for main spindle 14 Recess 15 X-axis ball screw (moving means)
16 Grinding wheel motor 17 Control device W Work Wa Work cam

Claims (2)

  The spindle head for rotationally driving the workpiece having the cam portion, the grinding wheel platform for rotationally driving the grinding wheel, and the workpiece and the grinding wheel relative to each other in a direction in which the grinding wheel approaches and separates toward the workpiece and in a direction parallel to the rotational axis of the workpiece. And a moving means for moving, the grinding wheel table is provided with the rotation axis of the grinding wheel at a right angle to the rotation axis of the workpiece, the grinding wheel has an outer peripheral surface bulging in an arc shape in the thickness direction of the grinding wheel, While rotating the workpiece and the grinding wheel, the grinding wheel is brought into contact with the outer periphery of the cam portion of the workpiece, and the cam having a recess on the outer periphery of the cam portion is ground by moving the workpiece and the grinding wheel relatively by the moving means. And cam grinding machine.   A grinding wheel rotating around an axis provided at a right angle to the rotation axis of the workpiece and having an outer circumferential surface bulging in an arc shape in the grinding wheel thickness direction is brought into contact with the outer circumference of the cam portion of the rotating workpiece. A cam grinding method comprising grinding a cam having a recess on an outer periphery of a cam portion by relatively moving a workpiece and a grinding wheel in a direction in which the grinding wheel approaches and separates and a direction parallel to a rotation axis of the workpiece.

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