JP2005262332A - Camshaft grinding method and grinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camshaft grinding method which does not require a phase sensor for measuring the phase of a cam and a phase reference for machining the cam. <P>SOLUTION: According to the camshaft grinding method, contact elements 42U, 42D of a sizing device 40 are brought into contact with the cam 50 of a camshaft 52 supported in a manner rotatable about an axial center C, and the camshaft 52 supported at the axial center C is rotated, to thereby measure the cam phase of the cam 50. Then the cam 50 is machined based on the measured cam phase. Thus the phase reference for machining the cam is not required for the camshaft 52. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, the camshaft is held and rotated between the main shaft constituting the shaft center and the center, and the grindstone is moved in the cutting direction in accordance with this rotation to grind the non-circular camshaft. The present invention relates to a camshaft grinding method and a grinding machine.

  Conventionally, in a grinding machine for processing a camshaft, the camshaft is held and rotated between the main shaft constituting the shaft center and the center, and the grindstone is moved in the cutting direction in synchronization with this rotation. A circular camshaft is ground.

Here, in order to grind the cam of a non-circular camshaft, it is necessary to phase the cam with respect to the axis. In order to achieve this phase alignment, in the prior art, a phase reference (pin, pin hole, key groove) is provided on the camshaft. As shown in FIG. 7A, the camshaft 52 including the cam 50 is fixed to the main shaft 25a of the headstock 25 with a chuck 52b, and the phase reference pin 48 on the main shaft side is inserted into the phase reference hole 54 on the camshaft 52 side. As a result, the phase of the cam 50 is matched to the headstock 25. FIG. 7B shows a bb cross section of FIG. While rotating the camshaft around the main shaft C and moving the grinding wheel 29 in the cutting direction X in response to this rotation, the cam 50 eccentric from the shaft center (main shaft) C is ground. Here, Patent Document 1 discloses a technique for detecting the phase of a cam using a sizing device. Patent Document 2 discloses a technique for grinding a camshaft without providing a phase reference.
Japanese Utility Model Publication No. 63-5406 JP-A-6-155125

  However, in the prior art, processing for providing a phase reference (pins, pin holes, key grooves) on the camshaft is required. Further, if there is a gap between the phase reference provided on the camshaft side and the phase reference provided on the main shaft side, a phase angle error has occurred in the cam by the gap. Furthermore, since it is necessary to perform machining in anticipation of this gap, it is necessary to set a large margin (black skin: ground part) in order not to grind parts that should not be ground on the cam. In addition, there is a problem that the grinding time becomes long in order to have a large amount of black skin.

  On the other hand, in Patent Document 2, the camshaft is ground without providing a phase reference, but there is a problem that it is necessary to separately provide a phase sensor for measurement.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a camshaft grinding method and a grinding machine capable of eliminating a phase reference for cam machining without providing a phase sensor. Is to provide.

In order to achieve the above object, the camshaft grinding method of the present invention rotates the camshaft while holding the camshaft between the main shaft constituting the shaft center and the center, and moving the grindstone in the cutting direction corresponding to this rotation. In a camshaft grinding method for grinding a cam of a non-round camshaft:
Contacting a sizing device contact with a cam of a camshaft rotatably supported on an axis;
Rotating the camshaft supported on an axis to measure the cam phase of the cam;
And a step of machining the cam based on the measured cam phase.

In addition, the grinding machine of the present invention holds and rotates the camshaft between the main shaft constituting the shaft center and the center, and moves the grindstone in the cutting direction in response to this rotation, so that it has a non-round shape. In grinding machines that grind camshaft cams:
Cam phase measuring means for measuring the cam phase of the cam by contacting the contact of the sizing device to the cam of the camshaft rotatably supported on the shaft, and rotating the camshaft;
And a processing means for processing the cam based on the measured cam phase.

  In the camshaft grinding method according to the first aspect, the contact of the sizing device is brought into contact with the cam of the camshaft rotatably supported on the shaft center, the camshaft supported on the shaft center is rotated, and the cam shaft Measure the cam phase. Then, the cam is processed based on the measured cam phase. For this reason, it is not necessary to provide a processing phase reference on the camshaft. Furthermore, the cam phase angle error caused by the error between the camshaft-side machining phase reference and the grinding machine-side phase reference can be eliminated, and machining accuracy can be improved and the grinding part can be reduced. Thus, the processing time can be shortened.

  According to the second aspect of the present invention, the cam phase is measured by setting the cam phase where the measured values of the upper contact and the lower contact of the sizing device are the same as the cam top position. For this reason, it is possible to accurately measure the cam phase.

  According to the third aspect, all cams of the camshaft are processed based on the measured cam phase of one cam. For this reason, the measurement time can be shortened, and the camshaft can be ground in a short time.

  According to the fourth aspect of the present invention, the cam phase of the cam at the center of the camshaft is measured, and all the cams of the camshaft, that is, the right and left cams of the center cam are processed based on the measured cam phase. When machining based on the phase reference provided at one end of the camshaft, the cam on the other end side has a large phase angle error because the machining position is far from the reference. On the other hand, in the present invention, the right and left cams close to the measured central cam are processed, so that the phase angle error of the cam on the camshaft end side can be reduced.

  In the grinding machine according to claim 5, the cam of the sizing device is brought into contact with the cam of the camshaft rotatably supported on the shaft center, and the camshaft supported on the shaft center is rotated so that the cam phase of the cam. Measure. Then, the cam is processed based on the measured cam phase. For this reason, it is not necessary to provide a processing phase reference on the camshaft. Furthermore, the cam phase angle error caused by the error between the camshaft-side machining phase reference and the grinding machine-side phase reference can be eliminated, and machining accuracy can be improved and the grinding part can be reduced. Thus, the processing time can be shortened.

[First embodiment]
FIG. 1 shows a grinding machine 20 according to a first embodiment of the present invention. The grinding machine 20 has a bed 22, and a workpiece table 23 is installed on the bed 22 so as to be movable in the Z-axis direction (traverse axis). The workpiece table 23 includes a servo motor 24 and the servo motor 24. Is moved in the Z-axis direction by a feed screw (not shown) rotated by.

  On the work table 23, a headstock 25 and a tailstock 26 are installed opposite to each other on the left and right. A chuck provided on the spindle 25a of the headstock 25 is provided between the headstock 25 and the tailstock 26. Both ends of the camshaft 52 are supported by 25b and a center 26a provided on the tailstock 26. The main shaft 25a is rotated by a main shaft motor 25M.

  In FIG. 1, a grindstone table 27 is installed on a bed 22 so as to be movable in an X-axis direction (cutting direction) perpendicular to the moving direction of the workpiece table 23, and a servo motor 28 fixed to the bed 22 and the servo motor 28. It is moved in the X-axis direction by a feed screw (not shown) rotated by the servo motor 28. A grinding wheel 29 that grinds the camshaft 52 and an inverter motor 30 that drives the grinding wheel 29 are attached to the grinding wheel base 27. The numerical controller 100 controls the motors 24, 25 M, 28, and 30 via the driving device 102.

  FIG. 2 shows an enlarged view of the camshaft 52 in FIG. A plurality of cams 50 are provided on the camshaft 52. At a position facing the grinding wheel 29 shown in FIG. 1, a sizing device 40 having a contact 42U for measuring the cam 50 of the camshaft 52 is arranged.

  FIG. 3A shows a cross section taken along the line AA in FIG. The sizing device 40 includes a lower contact 42D together with the upper contact 42U shown in FIG. 2, and is sent by the sizing feeder 44 to detect the cam 50 at the forward position as shown in FIG. 3B. I do. In the sizing device 40, the origin is set at the center of the camshaft 52, that is, on the horizontal line of the main shaft C. It should be noted that the horizontal line of the main axis C here does not mean a physical horizontal line, but means a relative positional relationship during measurement and processing. The upper contact 42U and the lower contact 42D are adjusted such that the cam profile pre-processed surface for measuring the phase angle is in contact with the horizontal offset of the spindle C in the vertical direction. In the first embodiment, the sizing device 40 is used not only for measuring the machining state of the cam 50 during machining, but also for measuring the phase of the cam before the machining starts, and the cam 50 is machined based on the measured phase. . As shown in FIG. 1, the sizing device 40 is controlled by the numerical control device 100 via the driving device 102.

The phase measurement of the cam 50 in the grinding machine according to the first embodiment will be described with reference to FIGS. 3 and 4.
FIG. 3A shows a state in which the camshaft 52 is carried in by a carry-in device (not shown). As shown in FIG. 3 (A), the shaft 25 is supported on the shaft C by the main shaft 25a and the center 26a of the tailstock 26 (see FIG. 2). In this charged state, the shaft center (main shaft) C and the cam top 50T are displaced from each other, that is, at a position deviated from the horizontal line on the shaft center C. First, as shown in FIG. 3B, the sizing device 40 is advanced so that the upper contact 42U and the lower contact 42D are located at the target position with the axis C interposed therebetween, and the contacts 42U and 42D are cammed. 50 cam profiles are brought into contact with the pre-machined surface. Then, as shown in FIG. 4A, the spindle motor 25M shown in FIG. 1 is driven to rotate the camshaft 52 slightly in the clockwise direction, and the measured values of the upper contact 42U and the lower contact 42D are the same. The camshaft 52 is rotated until Here, when the measured values of the upper contact 42U and the lower contact 42D do not become the same even when rotated clockwise, that is, as shown in FIG. 4 (B), the cam top 50T is a horizontal line on the axis C. If it is below, the cam shaft 52 is rotated counterclockwise, and the cam shaft 52 is rotated until the measured values of the upper contact 42U and the lower contact 42D become the same. As shown in FIG. 5, the horizontal line on the axis C intersects the cam top 50T by rotating the cam 50 so that the measured values of the upper contact 42U and the lower contact 42D are the same. . That is, since the cam 50 is symmetric with respect to a line segment connecting the axis C and the cam top 50T in the figure, the measured value of the upper contact 42U (a1 in the figure) and the measured value of the lower contact 42D. When (equal to a2 in the figure) becomes equal, the horizontal line on the axis C intersects the cam top 50T. In the first embodiment, cam processing is performed using this cam phase (phase in which the horizontal line on the axis C intersects the cam top 50T) as a phase reference.

FIG. 6 is a process diagram of the camshaft 52 grinding in the grinding machine of the first embodiment.
First, the camshaft 52 having a substantially finished shape by the forging process in the previous stage is carried in by a carry-in device (not shown) (S12), and the black skin left on the cam 50 in the subsequent processes is ground. The spindle 25a of the spindle stock 25 is advanced and inserted into the rear reference hole 50r of the camshaft 52 shown in FIG. 2 (S14), and the center 26a of the tailstock 26 is advanced to the front reference hole 50f of the camshaft 52. The camshaft 52 is held on the C axis (axial center C). Thereafter, the chuck 25b is closed and the camshaft 52 is fixed to the main shaft 25a (S18). Then, as described above with reference to FIG. 3B, the sizing device 40 is advanced to bring the upper contact 42U and the lower contact 42D into contact with the cam 50 (S20). Here, as shown in FIG. 2, among the plurality of cams of the camshaft 52, the central cam 50 with respect to the axis C is the measurement target. Then, as described above with reference to FIG. 4A, the spindle motor 25M shown in FIG. 1 is driven to slightly rotate the camshaft 52, and the outputs of the upper contact 42U and the lower contact 42D are equal. By stopping the rotation at the position, the cam top 50T of the cam 50 is phase aligned with the axis C (S22). Then, the sizing device 40 is retracted (S24). Thus, the phase detection of the cam 50 is completed, and the cam profile processing is performed by calculating the cam phase angle that has been input in advance with respect to the measured cam phase angle. Here, similarly to the prior art described above with reference to FIG. 7B, the cam 50 eccentric from the axis C is ground by moving the grinding wheel 29 in the cutting direction in accordance with the rotation of the camshaft 52. (S26). In the first embodiment, the phase of one cam 50 at the center is detected, and the right cam 50 and the left cam 50 in the center of the figure are ground.

  In the first embodiment, the cam phase of the cam at the center of the camshaft is measured, and all cams of the camshaft, that is, the right and left cams of the center cam are processed based on the measured cam phase. When processing is performed based on the phase reference provided at one end of the camshaft as in the prior art described above with reference to FIG. 7, the processing position of the cam at the other end is far from the reference. The phase angle error was large. On the other hand, in the first embodiment, the right and left cams close to the measured central cam are processed, and therefore the phase angle error of the cam on the camshaft end side can be reduced.

  In the grinding machine and the camshaft grinding method of the first embodiment, the contacts 42U and 42D of the sizing device 40 are brought into contact with the cam 50 of the camshaft 52 that is rotatably supported by the axis C, and the axis C is contacted. The cam phase of the cam 50 is measured by rotating the supported cam shaft 52. Then, the cam 50 is processed based on the measured cam phase. For this reason, it is not necessary to provide a processing phase reference on the camshaft 52. Furthermore, the cam phase angle error caused by the gap between the camshaft side processing phase reference 54 and the grinding machine side phase reference 48 in the prior art described above with reference to FIG. 7 can be eliminated. Processing accuracy can be increased. By increasing the processing accuracy, it becomes possible to reduce the excess black skin, that is, the grinding portion, which has been provided in the past to prevent the portion that should not be ground from being shaved, thereby shortening the processing time. it can.

  In the above-described embodiment, the phase measurement of the cam 50 has been described. However, the grinding machine and the camshaft grinding method of the present invention can be applied to various workpieces having a non-circular grinding portion.

It is a block diagram which shows the structure of the grinding machine which concerns on 1st Embodiment of this invention. It is explanatory drawing which expands and shows the camshaft in FIG. 3A and 3B are explanatory diagrams of cam phase detection in the grinding machine according to the first embodiment. 4A and 4B are explanatory diagrams of cam phase detection in the grinding machine according to the first embodiment. It is explanatory drawing of the phase detection of the cam in the grinding machine which concerns on 1st Embodiment. It is process drawing which shows the process of the camshaft grinding in the grinding machine of 1st Embodiment. FIG. 7A is an explanatory view showing camshaft grinding in a conventional grinding machine, and FIG. 7B is a cross-sectional view taken along line bb in FIG. 7A.

Explanation of symbols

20 grinding machine 25 spindle head 25a spindle 26 tailstock 26a center 27 grinding wheel base 28 servo motor 29 grinding wheel 40 sizing device 50 cam 50T cam top 52 camshaft C shaft center

Claims (5)

A camshaft that grinds the cam of a non-circular camshaft by holding and rotating the camshaft between the main shaft constituting the shaft center and the center and moving the grindstone in the cutting direction in response to this rotation In grinding method:
Contacting a sizing device contact with a cam of a camshaft rotatably supported on an axis;
Rotating the camshaft supported on an axis to measure the cam phase of the cam;
A camshaft grinding method comprising: machining the cam on the basis of the measured cam phase. The sizing device has an upper contact and a lower contact located at a target position across the axis, and the measurement of the cam phase is performed between the upper contact and the lower contact of the sizing device. 2. The camshaft grinding method according to claim 1, wherein the cam phase at which the measured values are the same is set to the cam top position. 3. The camshaft grinding method according to claim 1, wherein all cams of the camshaft are processed based on the measured cam phase of one cam. The camshaft grinding method according to claim 1 or 2, wherein the cam phase of a cam at a central portion of the camshaft is measured, and all cams of the camshaft are processed based on the measured cam phase. A grinding machine that grinds cams of non-circular camshafts by holding and rotating the camshaft between the main shaft and the center constituting the shaft center and moving the grindstone in the cutting direction in response to this rotation In:
Cam phase measuring means for measuring the cam phase of the cam by contacting the contact of the sizing device to the cam of the camshaft rotatably supported on the shaft, and rotating the camshaft;
And a processing means for processing the cam based on the measured cam phase.

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