JP4029602B2 - High-precision profile grinding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a profile grinding method for profile grinding (form grinding) of a cam surface of a cam and a tooth surface of a gear into a highly accurate shape.
[0002]
[Prior art]
Conventional high-accuracy profile grinding methods include point grinding (profile grinding that creates a shape by the movement of the grinding wheel according to the profile design value) and grinding while moving and positioning the tip of the grinding stone at each point of the shape to be machined. Then, the desired shape was ground.
However, when a highly accurate shape with a tolerance of 10 μm or less is required, the tip of the grindstone has a shape of about R0.1 mm as shown in FIG. There is a problem that the desired shape cannot be obtained because the desired shape is shifted by 10 μm or more from the desired shape.
[0003]
Also, when attaching the workpiece to the workpiece holding part of the grinding machine, deformation of the workpiece due to the clamping force, misalignment, inclination, etc. occur, and the error due to this also becomes 10 μm or more, There was a problem that a necessary shape could not be obtained.
Furthermore, when the measuring device is image measurement, if the focal length of the image measurement is short during measurement of the machining shape and the machining reference position, the workpiece reference part and the workpiece machining part cannot be directly measured, and the machining shape reference There was also a problem that positioning and correction could not be performed.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a high-precision profile grinding method capable of stably obtaining a high-precision shape having a tolerance of 10 μm or less.
[0005]
[Means for Solving the Problems]
The present invention provides a high-precision profile grinding method according to each of the claims as means for solving the above-mentioned problems.
Precision profile grinding method according to claim 1, first, the initial setting of the prior grinding wheel position in the profile grinding of the workpiece is performed, grinding wheel position for machining a workpiece are determined, then, A workpiece with a measuring part at one end and a workpiece with a machining part at the other end is attached to the workpiece holder, and the workpiece and measuring part of the workpiece are profile-grinded at the same time. Measure the shape, compare the measured machining shape with the stored machining shape, find the error, correct the relative movement amount of the grindstone based on this, and again the machining part and the measurement part at the same time After profile grinding, the measuring part is removed from the workpiece. In this way, in particular, by providing a measuring unit at one end within the measurable focal length of the workpiece and removing the measuring unit after profile grinding, the profile-ground shape of the workpiece is It is possible to measure accurately at high magnifications (without removing the workpiece) and by obtaining the amount of deviation from the desired shape and correcting the positioning position of the tip of the grindstone. An accurate shape can be obtained.
The high-accuracy profile grinding method of claim 2 specifically limits the procedure of profile grinding, and has the same effects as the method of claim 1.
[0006]
The high-accuracy profile grinding method according to claim 3 adds a procedure for initial positioning of the grindstone that is performed prior to profile grinding of the workpiece. The image measuring device is fixed to the grindstone head, and the dummy workpiece is covered. Attach the workpiece workpiece holding part to a fixed position on the table, profile grinding the dummy workpiece, measure the machining shape of the dummy workpiece with an image measuring device, and set the reference position of the machining shape of the dummy workpiece On the other hand, the processing reference position of the workpiece measuring unit is measured with an image measuring device to determine the reference position of the workpiece, and the reference of the workpiece measuring unit is measured from the time of measuring the reference position of the machining shape of the dummy workpiece. The moving amount of the image measuring device until the position measurement is stored, and the workpiece is added from the relative positional relationship between the stored moving amount of the image measuring device and the stored position of the grindstone head. Seeking grindstone position required, in which to perform a profile grinding after positioning the grinding wheel tip. Thereby, the position and inclination of the shape to be processed can be processed accurately, and a more accurate shape can be obtained.
According to the high-precision profile grinding method of the fourth aspect, the profile grinding is performed a plurality of times in accordance with the positioning of the grindstone and the correction of the profile grinding, thereby further improving the machining accuracy.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a high-precision profile grinding method according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic overall configuration diagram of a profile grinding apparatus for carrying out the high-precision profile grinding method of the present invention. The profile grinding apparatus 1 holds a workpiece 3 and is movable in the X-axis direction indicated by B in FIG. 1, and a disc-shaped grinding wheel 2 for grinding the workpiece 3. And the image measuring device 4 for measuring the processed shape of the workpiece 3.
[0008]
On the table 11, a fixed center 9 and a movable center 10, which are work holders 5 that hold the workpiece 3, are provided. The workpiece 3 is sandwiched between the fixed center 9 and the movable center 10. Retained. The movable center 10 is movable so that the interval formed between the movable center 10 and the fixed center 9 can be changed, and a rotation mechanism (not shown) for rotating the held workpiece 3 is provided. ing.
In the present invention, the workpiece 3 is provided with a machining portion 8 and a measuring portion 7, and the workpiece 3 is held by the work holder 5 so that the measuring portion 7 is on the fixed center 9 side. The
[0009]
The grindstone head 6 is provided with a rotation drive mechanism (not shown) for rotating the supported grindstone 2 and is movable in the Y-axis direction indicated by A and the Z-axis direction indicated by C in FIG. It is configured.
An image measuring device support 12 that supports the image measuring device 4 is fixed to the grindstone head 6.
Furthermore, a dummy workpiece holder 14 is provided so that the dummy workpiece 13 can be attached to a predetermined position on the table 11.
[0010]
FIG. 2 is a diagram for explaining how to obtain the grinding wheel origin when processing a workpiece. As shown in FIG. 2, the relative distances L1 (Y direction) and L2 (Z direction) between the machining origin of the dummy workpiece 13 and the machining origin of the workpiece 3 are measured, and the relative distances L1 and L2 and the dummy workpiece are processed. The grindstone position for machining the workpiece 3 is accurately determined from the known grindstone position. That is, the grindstone origin coordinates (Y, Z) obtained when the known grindstone origin coordinates (Y0, Z0) are Y = Y0 + L1, Z = Z0 + L2. As a result, the grindstone position necessary for processing the workpiece is determined. This only needs to be set once at the beginning of processing.
[0011]
FIG. 3A is a diagram for explaining point grinding, and shows profile grinding in which a shape is created by the movement of the grindstone 2 along the profile design value as shown in FIG. 3A.
FIG. 3B is a diagram for explaining the movement of the grindstone 2 during profile grinding. As shown in FIG. 3B, the movement of the grindstone 2 (the grindstone head 6) is positioned at the initial profile design value while the grindstone 2 is constantly rotated, and the workpiece 3 is moved as shown in FIG. A reciprocating movement in the X-axis direction indicated by A (A movement (1), (2)) to perform processing in one point and A direction, and then simultaneous movement in B (Y-axis direction) and C (Z-axis direction) Then, the grindstone 2 is moved to the second point (B, C movement (3)), and the A movement is performed again at this point to process the workpiece 3 in the 1 point / A direction. By repeating these steps, grinding of all profiles is completed.
[0012]
Next, the operation of the profile grinding apparatus having the above-described configuration, that is, a high-precision profile grinding method using this apparatus will be described.
First, the dummy workpiece 13 is set on the table 11, and the workpiece 3 having the machining unit 8 and the measuring unit 7 is held by the workpiece holder 5.
Next, the position of the grindstone head 6 is memorized, and the shape is processed by profile grinding by the movement of the table 11 and the grindstone head 6 (movement in the X, Y, and Z directions) with the grindstone 2 that rotates the dummy workpiece 13 at that position. . Next, the shape that has been ground at this time is measured by the image measuring device 4, and the measured machining shape is compared with a predetermined machining shape that is stored, and an error is obtained. While correcting the movement amount, the reference position of the machining shape of the dummy workpiece 13 and the reference position of the measuring unit 7 of the workpiece 3 are measured by the image measuring device 4, and the reference position of the machining shape of the dummy workpiece 13 is measured. The movement amount of the image measuring device 4 from when the measuring unit 7 of the workpiece 3 is measured to the reference position measurement is stored, and the relative positional relationship between the stored movement amount of the image measuring device 4 and the stored position of the grindstone head 6 is stored. From this, the grindstone position necessary for machining the workpiece 3 is obtained. That is, the initial setting of the grindstone position is performed by the method described above with reference to FIG. This can basically be performed once prior to processing of the workpiece.
[0013]
Next, based on the obtained grindstone position, the processed portion 8 of the workpiece 3 and the measuring portion 7 at one end thereof are simultaneously processed by profile grinding, and the shape processed at this time is processed by the image measuring device 4. The measured machining shape is compared with the stored predetermined machining shape to obtain an error. Based on this error, the relative movement amount of the grindstone 2 is corrected. To implement.
[0014]
Next, the movable center 10 of the workpiece holding unit 5 is rotated by a predetermined angle, for example, approximately 21.1765 ° to change the machining position of the workpiece 3, and the machining portion 8 of the workpiece 3 as described above. Then, shape processing by profile grinding of the measurement unit 7, measurement by the image measurement device 4, correction of the relative movement amount based on the measurement result, and re-profile grinding are performed. By repeating this a predetermined number of times (for example, 17 times), the workpiece is processed over the entire peripheral surface, and the tooth surface of the gear is profile-ground into a highly accurate shape. After the profile grinding, the measuring unit 7 is removed from the workpiece 3.
[0015]
【The invention's effect】
As described above, according to the present invention, the measuring unit is provided at one end of the workpiece, the measuring unit is removed after profile grinding, and the image measuring device is fixed to the grindstone head, and the dummy workpiece is processed. Mounted on the same table as the workpiece, profile grinding the dummy workpiece, positioning the grinding wheel tip so that the reference position of the workpiece and the reference position of the workpiece coincide, and profile grinding, the R shape of the grinding wheel tip Corresponding to the correction of the positioning position of the tip of the wheel during profile grinding, and accurately measuring the misalignment of the work piece that occurs when correcting the misalignment and inclination when mounting the work piece, By reflecting the positioning of the tip of the grindstone, a highly accurate shape with a tolerance of 10 μm or less can be obtained by profile grinding.
[Brief description of the drawings]
FIG. 1 is a schematic overall configuration diagram of a profile grinding apparatus for carrying out a high-precision profile grinding method according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining how to obtain a grinding wheel origin when processing a workpiece.
FIG. 3A is a diagram for explaining point grinding, and FIG. 3B is a diagram for explaining movement of a grindstone during profile grinding.
FIG. 4 is an enlarged view of a grindstone tip.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Profile grinding apparatus 2 ... Grinding stone 3 ... Workpiece 4 ... Image measuring device 5 ... Work holder 6 ... Grinding wheel head 7 ... Workpiece measuring part 8 ... Workpiece processing part 9 ... Fixing of work holder Center 10 ... Movable center 11 of work holder ... Table 12 ... Image measuring device support 13 ... Dummy work

Claims (4)

In the method of profile grinding with high precision by point grinding the outer periphery of the workpiece using a disc-shaped grindstone,
First, prior to profile grinding of the workpiece, initial setting of the grindstone position is performed, and the grindstone position for machining the workpiece is determined,
Next , a work piece provided with a measurement part at one end and a work part at the other end side is held and held between a fixed center and a movable center of the work holding part,
Profile grinding of the workpiece part and the measurement part at the same time,
After this profile grinding, measure the processing shape of the measurement unit with an image measurement device,
Comparing the measured machining shape with the stored machining shape to determine the error,
The relative movement amount of the grindstone is corrected with the error, and again the profile grinding is performed on the workpiece and the measurement unit of the workpiece simultaneously ,
After the second profile grinding, the high-precision profile grinding method is characterized in that the measuring section is removed from the workpiece. The profile grinding process
Said moved relative to the workpiece point grinding the grinding wheel in the X-axis direction (A) is a direction perpendicular against the axis of rotation of the grinding wheel,
Next, the grindstone is moved and positioned relative to the workpiece in the Y-axis direction (B) that is the rotation axis direction of the grindstone and the Z-axis direction (C) that is the cutting direction of the grindstone, and then the grindstone relatively moving allowed point grinding against the workpiece in the X-axis direction (a) is a direction perpendicular against the axis of rotation of the grinding wheel,
The high-precision profile grinding method according to claim 1, wherein these steps are repeated. Initial setting of the grindstone position performed prior to profile grinding of the workpiece is
Fixing the image measuring device to the grindstone head;
Attaching the workpiece to the workpiece holder,
On the other hand, after attaching the dummy workpiece to a predetermined position on the table to which the workpiece holder is fixed, the dummy workpiece is profile ground,
The processing shape of the dummy workpiece is measured by the image measuring device to obtain a reference position of the processing shape of the dummy workpiece,
On the other hand, the processing reference position of the measurement unit of the workpiece is measured by the image measuring device to obtain the reference position of the workpiece,
Storing the movement amount of the image measuring device from the reference position measurement of the machining shape of the dummy workpiece to the reference position measurement of the measurement unit of the workpiece;
The grindstone position required for processing the workpiece is obtained from a relative positional relationship between the stored movement amount of the image measuring device and the stored position of the grindstone head . High-precision profile grinding method.   The high-precision profile grinding method according to any one of claims 1 to 3, wherein profile grinding is performed a plurality of times in accordance with positioning of the grindstone and correction of the profile grinding.

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