JPH0567447U - Thermal displacement compensator - Google Patents

Abstract

(57) [Abstract] [Purpose] To stabilize the work accuracy by measuring the thermal displacement around the processing tool and correcting the thermal displacement by a simple means. [Structure] A reference surface is formed around the processing tool, a non-contact detection head is provided at a position corresponding to the reference surface on the non-moving side, and the reference surface is appropriately engaged with the detection head to measure the thermal displacement amount. , X, Y, Z correction. [Effect] While simplifying the device and reducing the cost,
The correction amount detection time can be shortened.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention measures the amount of thermal displacement of a member that holds a processing tool in a state where thermal displacement is likely to occur, such as a spindle that is supported by a grindstone of a grinding machine and rotates, and that is supported by a column. The present invention relates to a thermal displacement correction device suitable for detecting a correction amount to be corrected for thermal displacement.

[0002]

[Prior Art]

 For example, in a grinder having a spindle holding a grindstone on the tip side and being cantilevered by a column mounted on a bed, the tip side of the spindle is likely to be thermally displaced. If the predetermined grinding is carried out while the thermal displacement is maintained, the work cannot be finished with a predetermined size with high precision. Therefore, in the past, processing machines that are sensitive to thermal displacement have been installed in a constant temperature room where the room temperature is constant, or they have been cooled by using a fan and a cooler to minimize thermal displacement. In addition, there was also a system in which a machining program was formed to automatically incorporate a correction amount corresponding to a temperature change around a processing tool into a control device side based on an empirical value to perform thermal displacement correction.

[0003]

[Problems to be solved by the device]

 In factories that handle large quantities of precision processed products, it is necessary to install all processing machines in a temperature-controlled room. However, the equipment cost of the temperature-controlled room is expensive, and in many cases it is practically impossible to satisfy the above conditions. Further, when the processing machine is cooled by a fan, a cooling machine, etc., it is difficult to uniformly cool each part of the processing machine according to the heat generation degree of each part, and it is impossible to eliminate thermal displacement. In addition, it is difficult to control the degree of cooling, and problems such as overcooling tend to occur.

The present invention was devised in view of the above circumstances, and it is possible to easily measure the amount of thermal displacement around a processing tool by a simple means and to detect the amount of thermal displacement correction so that the amount of thermal displacement correction can be detected. The purpose is to provide a device.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention forms a reference surface in the thermal displacement direction of a member holding a processing tool and in a direction intersecting with the thermal displacement direction, and at a position facing the reference surface on the stationary side of a processing machine. In addition, a thermal displacement correction device is provided which is provided with a non-contact detection head that detects the displacement amount of the reference surface.

[0006]

[Action]

 In the initial state where thermal displacement does not occur, the reference surface formed in the portion holding the processing tool is engaged with the detection head installed on the stationary side to obtain the initial value. When thermal displacement occurs, the reference surface is appropriately engaged with the detection head side, and the difference from the initial value is obtained to obtain the correction amount. By inputting the correction amount into the control device of the processing machine and performing corrections in the X, Y, and Z directions, the processing tool can be held at almost the same position as in the initial state.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, a grinding machine is adopted as a processing machine, but of course the invention is not limited to this. As shown in FIG. 1, a grindstone 4 having a grindstone flange 3 is fixed to the tip of a spindle 5. A headstock 12 that pivotally supports the main shaft 5 is cantilevered by a column 13 and moves along the Y-axis direction (vertical direction). The column 13 is placed on the bed 14. On the other hand, a table 15 is slidably supported on the bed 14 along the Z-axis direction (front-rear direction), and a saddle 16 is slid on the table 15 along the X-axis direction (left-right direction in the plane of the drawing). Freely supported. The work 10 held by the chuck 17 is mounted on the saddle 16. On the other hand, a support 11 is placed on the table 15, and the first detection head 1 and the second detection head 2 are fixed on the support 11. The first and second detection heads 1 and 2 are non-contact type detection heads, and are connected to the correction value calculation unit 8 of the NC device 9. In this embodiment, the first detection head 1 is arranged along the Y-axis direction, and the second detection head 2 is arranged along the Z-axis direction. The first and second detection heads and the support base 11 for supporting them are arranged at a position where they do not interfere with the grindstone flange 3 and the spindle 5 side during processing of the workpiece 10 by the grindstone 4. On the other hand, a first reference surface 6 is formed on the outer peripheral portion of the grindstone flange 3, and a second reference surface 7 is formed on the end surface of the grinding wheel flange 3 which is orthogonal to the first reference surface 6. The first and second reference planes 6 and 7 are formed from those having highly accurate roundness and flatness. The first reference surface 6 engages with the first detection head 1, and when the first reference surface 6 is brought close to the first detection head 1 side, a slight gap is formed between them. To be done. The second reference surface engages with the second detection head at a position with a slight gap. As described above, since the first and second detection heads are composed of non-contact type detection heads, the amount of displacement of the first and second reference planes 6 and 7 should be measured through the gap. Comes out.

Next, the operation of this embodiment will be described. As shown in FIG. 2, the table 15 is moved to the grindstone 4 side to engage the first and second detection heads 1 and 2 with the first and second reference surfaces 6 and 7 prior to processing. .. Thereby, initial values in the Y-axis direction and the Z-axis direction are obtained and stored in the NC device 9 side. Although the detection head is not provided in the X-axis direction in this embodiment, in the case of the grinder having the structure shown in FIG. 1, since the displacement of the grindstone 4 occurs mainly in the Y-axis direction and the Z-axis direction, This is because no axial correction is required. Of course, the detection head may be arranged also in the X-axis direction. Next, as shown in FIG. 1, the table 15 and the saddle 16 are moved in the Z-axis direction and the X-axis direction, and the workpiece 10 held by the chuck 17 is positioned immediately below the grindstone 4. Further, the headstock 12 is moved along the Y-axis direction to bring the grindstone 4 and the workpiece 10 into contact with each other. The work 10 is ground by rotating the main shaft 5 and moving the saddle 16 in the X-axis direction. The correction amount is detected when thermal displacement begins to occur due to the progress of processing. Judgment of the occurrence of thermal displacement depends on experience, but it is desirable to make a time schedule for the detection time in advance. The engagement between the grindstone 4 and the workpiece 10 is stopped, the headstock 12 is moved along the Y-axis direction, the table 15 is moved in the Z-axis direction, and the grindstone flange 3 is returned to the position where the initial value was measured. As described above, the first and second detection heads 1 and 2 are engaged with the first and second reference surfaces 6 and 7 in a non-contact state. When the grindstone flange 3 is not thermally displaced at all, the gap between the first and second detection heads 1 and 2 and the first and second reference surfaces 6 and 7 is exactly the same as in the initial state. However, when the grindstone flange 3 is thermally displaced, the gap changes. The first and second detection heads 1 and 2 input the detected value in the state where the gap is changed to the correction value calculation unit 8 of the NC device 9. The correction value calculation unit 8 compares the initial value that was previously input and stored with the detected value that was input this time, and obtains the amount of change as the correction value. The correction values are input to the Y-axis and Z-axis correction control unit (not shown) of the NC device, and the Y-axis and Z-axis corrections of the headstock 12 and the table 15 are automatically performed. After that, the grindstone 4 and the work 10 are aligned again and the grinding process is continued. After that, the same operation is repeated. As described above, in the case of this embodiment, the first and second detection heads 1 and 2 and the first and second reference surfaces 6 and 7 can be simply engaged as needed. The correction amount is automatically detected by the operation, and the correction is performed by the NC device 9. Therefore, the grindstone 4 and the work 10 are always kept under the same conditions as in the initial state. Thereby, highly accurate grinding is performed.

In this embodiment, the detection head is not arranged in the X-axis direction as described above, but it may be arranged, of course. Although the first and second reference surfaces are formed on the grindstone flange 3, the invention is not limited to this. Further, although the present embodiment has described the grinder, the processing machine is not limited to the grinder. Further, in this embodiment, the first and second reference planes 6 and 7 and the first and second detection heads 1 and 2 arranged corresponding thereto are arranged orthogonally to each other, but it is not always limited thereto. Not a thing. Further, although the first and second detection heads 1 and 2 corresponding to the first and second reference planes 6 and 7 are single, they may be arranged in parallel.

[0010]

[Effect of the device]

 According to the present invention, the following effects can be obtained. (1) When a thermal displacement occurs, the thermal displacement amount can be obtained by a simple operation of simply engaging the reference surface formed at the displacement portion with the detection head arranged at a predetermined position. By correcting the X, Y, and Z axes based on the values, the position of the processing tool is corrected, and highly accurate processing is performed. (2) Since the first and second reference surfaces may be formed on the member itself that holds the processing tool, no special separate member is required. Therefore, it can be implemented extremely easily and inexpensively. (3) Further, it is not necessary to use a special detecting head, and a known general non-contact detecting head is used. Therefore, the equipment cost is low.

[Brief description of drawings]

FIG. 1 is a side view showing the overall structure of an embodiment of the present invention.

FIG. 2 is an enlarged partial cross-sectional view around a detection head for explaining the operation of the present embodiment.

[Explanation of symbols]

 1 1st detection head 2 2nd detection head 3 Grindstone flange 4 Grindstone 5 Spindle 6 1st reference surface 7 2nd reference surface 8 Correction value calculation part 9 NC device 10 Work 11 Support stand 12 Spindle stand 13 Column 14 Bed 15 Table 16 Saddle 17 Chuck

Claims (1)

[Scope of utility model registration request] 1. A reference plane is formed in a thermal displacement direction of a member holding a processing tool and a direction intersecting with the thermal displacement direction, and a displacement amount of the reference plane is set at a position opposite to the stationary reference plane of the processing machine. A thermal displacement correction device comprising a non-contact detection head for detection.