Method and structure for correcting thermal displacement of spindle box of numerical control machine tool

Abstract

The invention discloses a method and a structure for correcting thermal displacement of a spindle box of a numerical control machine tool, and belongs to the field of machine tools. A mounting plate is made of materials different from the spindle box in thermal expansion coefficient, the tail end of the mounting plate is fixed to the bottom of the spindle box, other portions of the mounting plate are slidably mounted on the spindle box, and the extending direction of the mounting plate is the same as that of the spindle box. The reading head mounting rack is fixed at the other end of the mounting plate, and the reading head is fixed on the reading head mounting rack; when the spindle box generates thermal displacement, the tail end of the mounting plate moves along with the bottom of the spindle box due to different thermal expansion coefficients of materials of the mounting plate and the spindle box, and one end of the mounting plate for fixing the reading head mounting rack slides relative to the spindle box, so that the reading head generates displacement relative to the bottom of the spindle box; when the reading head displaces, the grating ruler can correct the position of the reading head in real time, and the corrected displacement is the thermal displacement of the spindle box, so that the thermal displacement of the spindle box is corrected, and the part machining precision is improved.

Description

Technical Field

[0001] The invention relates to the field of numerical control, and in particular to a method and a structure for correcting thermal displacement of a spindle box of a numerical control machine tool. Background Art

[0002] The existing CNC machine tool grating ruler is fixed on the upper part of the spindle box and moves with the spindle box, and the reading head is installed in a fixed position on the slide saddle. Due to the overall layout of the CNC machine tool, the grating ruler can only be installed in the upper position of the spindle box. When the grating ruler is installed in the upper position, the grating ruler can correct the thermal displacement of the upper part of the spindle box, but the thermal displacement of the lower part of the spindle box cannot be corrected. During the processing, the positioning accuracy will deviate due to the inability to control the thermal displacement of the lower part, and the tool tip position will shift relative to the initial coordinate, resulting in deviations in the size of the processed parts. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, one of the objectives of the present invention is to provide a method for correcting the thermal displacement of a spindle box of a CNC machine tool, which can correct the overall thermal displacement of the spindle box and improve the machining accuracy of parts.

[0004] In order to overcome the deficiencies of the prior art, a second object of the present invention is to provide a structure for correcting the thermal displacement of a spindle box of a CNC machine tool, which can correct the overall thermal displacement of the spindle box and improve the machining accuracy of parts.

[0005] One of the purposes of the present invention is achieved by the following technical solution:

[0006] A method for correcting thermal displacement of a spindle box of a CNC machine tool comprises the following steps:

[0007] The grating ruler is fixedly installed on the saddle;

[0008] The mounting plate is made of a material having a different thermal expansion coefficient from that of the spindle box, the end of the mounting plate is fixed to the bottom of the spindle box, the other parts of the mounting plate are slidably mounted on the spindle box, and the extending direction of the mounting plate is the same as the extending direction of the spindle box;

[0009] The reading head mounting frame is fixed to the other end of the mounting plate, and the reading head is fixed to the reading head mounting frame;

[0010] When the spindle box produces thermal displacement, due to the different thermal expansion coefficients of the materials of the mounting plate and the spindle box, the end of the mounting plate moves with the bottom of the spindle box, and the mounting plate fixes one end of the reading head mounting frame and slides with the spindle box, causing the reading head to be displaced relative to the bottom of the spindle box. When the reading head is displaced, the grating ruler will correct the position of the reading head in real time. The corrected displacement is the thermal displacement of the spindle box, thereby correcting the thermal displacement of the spindle box.

[0011] Furthermore, the thermal expansion coefficient of the mounting plate is lower than the thermal expansion coefficient of the spindle box.

[0012] Furthermore, the mounting plate is made of iron-nickel alloy.

[0013] Furthermore, other parts of the mounting plate are slidably mounted on the spindle box via a pressing block.

[0014] The second object of the present invention is achieved by adopting the following technical solution:

[0015] A structure for correcting the thermal displacement of a spindle box of a numerically controlled machine tool is used to implement any of the above-mentioned methods for correcting the thermal displacement of a spindle box of a numerically controlled machine tool. The structure for correcting the thermal displacement of a spindle box of a numerically controlled machine tool comprises a spindle box, a saddle, a grating ruler and a reading head, wherein the grating ruler is fixed to the saddle. The structure for correcting the thermal displacement of a spindle box of a numerically controlled machine tool also comprises a mounting plate and a reading head mounting frame. The thermal expansion coefficient of the mounting plate is different from that of the spindle box. The end of the mounting plate is fixed to the bottom of the spindle box, and the rest of the mounting plate is slidably mounted on the spindle box. The reading head mounting frame is fixed to the other end of the mounting plate, and the reading head is fixed to the reading head mounting frame.

[0016] Furthermore, the spindle box and the saddle are both arranged vertically.

[0017] Furthermore, the modified CNC machine tool spindle box thermal displacement structure also includes a pressing block, which is fixed to the spindle box and is buckled with the mounting plate.

[0018] Furthermore, the pressing block is in an inverted L shape.

[0019] Furthermore, there are multiple pressing blocks, which are arranged in pairs, and the mounting plate is located between two pressing blocks.

[0020] Furthermore, the modified CNC machine tool spindle box thermal displacement structure also includes screws and pins, and the end of the mounting plate is fixed to the bottom of the spindle box by the screws and the pins.

[0021] Compared with the prior art, the method for correcting the thermal displacement of the spindle box of a CNC machine tool of the present invention is to fix the grating ruler on the saddle; a mounting plate is made of a material with a different thermal expansion coefficient from the spindle box, the end of the mounting plate is fixed to the bottom of the spindle box, and the other parts of the mounting plate are slidably mounted on the spindle box, and the extension direction of the mounting plate is the same as the extension direction of the spindle box; a reading head mounting frame is fixed to the other end of the mounting plate, and the reading head is fixed to the reading head mounting frame; when the spindle box generates thermal displacement, due to the different thermal expansion coefficients of the materials of the mounting plate and the spindle box, the end of the mounting plate moves with the bottom of the spindle box, and one end of the mounting plate fixing the reading head mounting frame slides with the spindle box, causing the reading head to be displaced relative to the bottom of the spindle box, and when the reading head is displaced, the grating ruler will correct the position of the reading head in real time, and the corrected displacement is the thermal displacement of the spindle box, thereby correcting the thermal displacement of the spindle box and improving the machining accuracy of parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A flow chart of a method for correcting thermal displacement of a spindle box of a CNC machine tool according to the present invention;

[0023] Figure 2 A three-dimensional diagram of the thermal displacement structure of the spindle box of a CNC machine tool corrected by the present invention;

[0024] Figure 3 for Figure 2 Correct the enlarged view of the thermal displacement structure A of the CNC machine tool spindle box;

[0025] Figure 4 for Figure 2 Corrected enlarged view of the thermal displacement structure B of the CNC machine tool spindle box.

[0026] In the figure: 1. spindle box; 2. saddle; 3. fixing plate; 4. grating scale; 5. mounting plate; 6. reading head mounting bracket; 7. screw; 8. pin; 9. pressure block. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0029] See also Figures 1 to 4 The present invention provides a method for correcting thermal displacement of a spindle box of a numerically controlled machine tool, comprising the following steps:

[0030] The grating ruler 4 is fixedly mounted on the saddle 2;

[0031] The mounting plate 5 is made of a material having a different thermal expansion coefficient from the spindle box 1, the end of the mounting plate 5 is fixed to the bottom of the spindle box 1, and the other parts of the mounting plate 5 are slidably mounted on the spindle box 1, and the extending direction of the mounting plate 5 is the same as the extending direction of the spindle box 1;

[0032] The reading head mounting frame 6 is fixed to the other end of the mounting plate 5, and the reading head is fixed to the reading head mounting frame 6;

[0033] When the spindle box 1 produces thermal displacement, due to the different thermal expansion coefficients of the materials of the mounting plate 5 and the spindle box 1, the end of the mounting plate 5 moves with the bottom of the spindle box 1, and the end of the mounting plate 5 fixing the reading head mounting frame 6 slides with the spindle box 1, causing the reading head to be displaced relative to the bottom of the spindle box 1. When the reading head is displaced, the grating ruler 4 will correct the position of the reading head in real time. The corrected displacement is the thermal displacement of the spindle box 1, thereby correcting the thermal displacement of the spindle box 1.

[0034] Specifically, the thermal expansion coefficient of the mounting plate 5 is lower than that of the spindle box 1. The mounting plate 5 is made of an iron-nickel alloy, specifically 4J36. The thermal expansion coefficient of the iron-nickel alloy material is extremely low within the range of 0 to 100°C, and the external dimensions can remain almost unchanged. The other parts of the mounting plate 5 are slidably mounted on the spindle box 1 through the pressing block 9, that is, only the end of the mounting plate 5 is fixed to the bottom of the spindle box 1, and the rest of the mounting plate 5 is slidably mounted on the spindle box 1, which is an open structure. The mounting plate 5 is integrally formed.

[0035] The method for correcting the thermal displacement of the spindle box of a CNC machine tool of the present invention comprises the following steps: fixing a grating ruler 4 on a saddle 2; using a material with a different thermal expansion coefficient from the spindle box 1 to make a mounting plate 5, the end of the mounting plate 5 is fixed to the bottom of the spindle box 1, and the other parts of the mounting plate 5 are slidably mounted on the spindle box 1, and the extension direction of the mounting plate 5 is the same as the extension direction of the spindle box 1; a reading head mounting frame 6 is fixed to the other end of the mounting plate 5, and the reading head is fixed to the reading head mounting frame 6; when the spindle box 1 generates thermal displacement, due to the different thermal expansion coefficients of the materials of the mounting plate 5 and the spindle box 1, the end of the mounting plate 5 moves with the bottom of the spindle box 1, and one end of the mounting plate 5 fixing the reading head mounting frame 6 slides with the spindle box 1, so that the reading head is displaced relative to the bottom of the spindle box 1, and when the reading head is displaced, the grating ruler 4 will correct the position of the reading head in real time, and the corrected displacement is the thermal displacement of the spindle box 1, thereby correcting the thermal displacement of the spindle box 1 and improving the machining accuracy of parts.

[0036] The present application also discloses a structure for correcting thermal displacement of a spindle box of a CNC machine tool, which is used to implement any of the above methods for correcting thermal displacement of a spindle box of a CNC machine tool. The structure for correcting thermal displacement of a spindle box of a CNC machine tool comprises a spindle box 1, a saddle 2, a fixing plate 3, a grating ruler 4, a mounting plate 5, a reading head mounting frame 6, a screw 7, a pin 8 and a pressing block 9.

[0037] The spindle box 1 is arranged vertically.

[0038] The slide saddle 2 is vertically arranged, and the slide saddle 2 is parallel to the spindle box 1 .

[0039] The fixing plate 3 is fixed to the slide saddle 2, and the fixing plate 3 extends in the vertical direction. The grating ruler 4 is fixed to the fixing plate 3. The grating ruler 4 extends from the top end to the bottom end of the slide saddle 2.

[0040] The thermal expansion coefficient of the mounting plate 5 is lower than that of the spindle box 1. The mounting plate 5 is made of an iron-nickel alloy, and the specific model is 4J36. The thermal expansion coefficient of the iron-nickel alloy material is relatively small in the range of 0 to 100°C, and the external dimensions are relatively stable. The end of the mounting plate 5 is fixed to the bottom of the spindle box 1, and the other parts of the mounting plate 5 are slidably installed on the spindle box 1, and the mounting plate 5 extends in the vertical direction. Specifically, the end of the mounting plate 5 is fixed to the bottom of the spindle box 1 by a screw 7 and a pin 8. There are a plurality of pressing blocks 9, and the plurality of pressing blocks 9 are arranged in pairs. Each pressing block 9 is in an inverted L shape, and the mounting plate 5 is located between the two pressing blocks 9.

[0041] The reading head mounting frame 6 is fixed to the top of the mounting plate 5. The reading head is fixed to the reading head mounting frame 6. The grating ruler 4 is parallel to the mounting plate 5, and the grating ruler 4 and the mounting plate 5 have the same length.

[0042] The present application discloses a structure for correcting the thermal displacement of a CNC machine tool spindle box, which can correct the thermal displacement of the CNC machine tool spindle box in real time to ensure the accuracy of the tool tip coordinates; the structure for correcting the thermal displacement of the CNC machine tool spindle box is a purely mechanical connection, without an additional detection unit to detect the thermal displacement, and is simple to install and highly reliable in use; the problem of poor surface quality caused by intermittent compensation caused by the use of a compensation algorithm can be solved.

[0043] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which are equivalent modifications and improvements made to the above embodiments based on the essential technology of the present invention, and all of them belong to the protection scope of the present invention.

Claims

1. A method for correcting thermal displacement of a spindle box of a CNC machine tool, characterized in that: The following steps are involved: The grating ruler is fixedly installed on the saddle; The mounting plate is made of a material having a different thermal expansion coefficient from that of the spindle box, the end of the mounting plate is fixed to the bottom of the spindle box, the other parts of the mounting plate are slidably mounted on the spindle box, and the extending direction of the mounting plate is the same as the extending direction of the spindle box; The reading head mounting frame is fixed to the other end of the mounting plate, and the reading head is fixed to the reading head mounting frame; When the spindle box produces thermal displacement, due to the different thermal expansion coefficients of the materials of the mounting plate and the spindle box, the end of the mounting plate moves with the bottom of the spindle box, and the mounting plate fixes one end of the reading head mounting frame and slides with the spindle box, causing the reading head to be displaced relative to the bottom of the spindle box. When the reading head is displaced, the grating ruler will correct the position of the reading head in real time. The corrected displacement is the thermal displacement of the spindle box, thereby correcting the thermal displacement of the spindle box.

2. The method for correcting thermal displacement of a CNC machine tool spindle box according to claim 1, characterized in that: The thermal expansion coefficient of the mounting plate is lower than the thermal expansion coefficient of the spindle box.

3. The method for correcting thermal displacement of a CNC machine tool spindle box according to claim 2, characterized in that: The mounting plate is made of iron-nickel alloy.

4. The method for correcting thermal displacement of a CNC machine tool spindle box according to claim 2, characterized in that: The other parts of the mounting plate are slidably mounted on the spindle box through a pressing block.

5. A structure for correcting thermal displacement of a spindle box of a CNC machine tool, used for implementing the method for correcting thermal displacement of a spindle box of a CNC machine tool as claimed in any one of claims 1 to 4, wherein the structure for correcting thermal displacement of a spindle box of a CNC machine tool comprises a spindle box, a saddle, a grating ruler and a reading head, and is characterized in that: The grating scale is fixed to the saddle, and the structure for correcting the thermal displacement of the CNC machine tool spindle box also includes a mounting plate and a reading head mounting bracket. The thermal expansion coefficient of the mounting plate is different from that of the spindle box. The end of the mounting plate is fixed to the bottom of the spindle box, and the rest of the mounting plate is slidably installed on the spindle box. The reading head mounting bracket is fixed to the other end of the mounting plate, and the reading head is fixed to the reading head mounting bracket.

6. The structure for correcting thermal displacement of a spindle box of a CNC machine tool according to claim 5, characterized in that: The spindle box and the saddle are both arranged vertically.

7. The structure for correcting thermal displacement of a spindle box of a CNC machine tool according to claim 6, characterized in that: The structure for correcting thermal displacement of a spindle box of a CNC machine tool further comprises a pressing block, which is fixed to the spindle box and is buckled with the mounting plate.

8. The structure for correcting thermal displacement of a spindle box of a CNC machine tool according to claim 7, characterized in that: The pressing block is in an inverted L shape.

9. The structure for correcting thermal displacement of a spindle box of a CNC machine tool according to claim 8, characterized in that: There are multiple pressing blocks, which are arranged in pairs, and the mounting plate is located between two pressing blocks.

10. The structure for correcting thermal displacement of a spindle box of a CNC machine tool according to claim 5, characterized in that: The modified CNC machine tool spindle box thermal displacement structure also includes screws and pins, and the end of the mounting plate is fixed to the bottom of the spindle box through the screws and the pins.

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