A machine tool static stiffness testing fixture and testing method

Abstract

The present invention is applicable to the field of machine tool technology and provides a machine tool static stiffness test fixture and test method, including a standard stress test rod and a mounting base, wherein the mounting base has a rotating assembly, the output end of the rotating assembly is mounted with a clamping platform, the movable clamping mouth of the clamping platform has an electronic thrust gauge, the top of the fixed clamping mouth is provided with a bracket, a rotating block is mounted on the bracket, and thrust pieces are fixed on the two planes of the rotating block. The working piece at the bottom of the standard stress test rod is a cube, and the test fixture also includes a micrometer in contact with the surface of the working piece. The present invention measures the static stiffness curve of the whole machine in two or three directions, and then simulates the standard stress test rod to obtain the simulated static stiffness curve of the test rod. The static stiffness curve of the machine tool spindle can be obtained by subtracting the curves, and the calculation method is simple. A boss is formed outwardly on the top of the working piece. Through the guiding effect of the slide rail and the support frame, the thrust gauge will not be offset in the Z direction and the lateral direction, thereby ensuring the measurement accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of machine tools, and in particular relates to a static stiffness testing fixture and a testing method for a machine tool. Background Art

[0002] Static stiffness is an important performance indicator for evaluating the load-bearing capacity of the end of a machine tool. It characterizes the ability to resist elastic deformation after the action of cutting forces. Establishing a static stiffness model that can reflect the mapping relationship between the local stiffness of components and joints and the end stiffness is the first step in guiding the design of static stiffness matching. The static stiffness of a machine tool spindle refers to the ability of the spindle to resist deformation under the action of cutting forces. It is usually expressed as the force applied in the displacement direction when the front end of the spindle produces a unit displacement. The static stiffness of the spindle is an important indicator for evaluating the quality of the entire CNC machine tool and is also an important indicator for the design of machine tool spindles. It can not only reflect the vibration resistance and stability of the spindle unit, but the static performance of the CNC machine tool spindle will affect its dynamic characteristics. The static deformation of the CNC machine tool spindle under the action of constant load and its own gravity will not only change the geometric accuracy of the parts and reduce the processing quality, but also serve as the basis for predicting the dynamic characteristics of the spindle, bearing life and noise.

[0003] Currently, when testing the static stiffness of machine tools, a force gauge is typically fixed to the machine table. The force gauge then applies a load to the machine spindle, and a dial indicator is used to measure the spindle's deformation relative to the table. The dial indicator reading under a specific load is then recorded. Finally, a static stiffness curve for that direction is fitted based on a series of discrete points of load and deformation data. However, in practice, the force gauge is required to apply a load to the machine spindle, and the spindle's irregular shape causes relative movement between the force gauge and the spindle, affecting the test results. Summary of the Invention

[0004] In view of the above problems, the purpose of the present invention is to provide a machine tool static stiffness testing fixture and testing method, aiming to solve the above technical problems.

[0005] The present invention adopts the following technical solutions:

[0006] The machine tool static stiffness test fixture includes a standard force-bearing test rod for vertical installation on the machine tool spindle, and also includes a mounting base, a rotating component is provided on the mounting base, a clamping platform is installed on the output end of the rotating component, an electronic thrust gauge is fixed to the top of the movable clamping mouth of the clamping platform through a connecting plate, a bracket is provided on the top of the fixed clamping mouth of the clamping platform, a rotating block is installed on the bracket, and push pieces are fixed on the two planes of the rotating block, and the two push pieces are vertically arranged, the standard force-bearing test rod includes a connecting column and an action piece formed at the bottom of the connecting column, the action piece is cubic, and the test fixture also includes a micrometer that contacts the surface of the action piece.

[0007] Furthermore, the top of the active member is shaped into a boss.

[0008] Furthermore, the four vertical sides of the active member are forty-five degree slopes.

[0009] Furthermore, a guide rail is provided at the bottom of the rear portion of the connecting plate, a matching slider is installed on the guide rail, a slot plate is provided at the bottom of the slider, a plurality of positioning slots are formed at angles on the mounting base, and a matching support frame is inserted between the slot plate and one of the positioning slots.

[0010] Furthermore, both the slot plate and the positioning slot are provided with dovetail slots, and the two sections of the support frame are dovetail blocks matching the dovetail slots.

[0011] Furthermore, a baffle is fixed to the end of the connecting plate.

[0012] On the other hand, the machine tool static stiffness testing method comprises the following steps:

[0013] Step S101: Adjust the height of the standard force-checking rod on the machine tool spindle so that the electronic thrust gauge is aligned with one Y-direction surface of the working member. Adjust the movement of the clamping platform so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-checking rod. Then, reset the electronic thrust gauge. Apply the dial indicator to the other Y-direction surface of the working member of the standard force-checking rod and reset it. Then, gradually drive the electronic thrust gauge to record the force values ​​and corresponding dial indicator displacement values ​​at several test points, thereby completing the data recording in the Y direction of the standard force-checking rod.

[0014] Step S102: Retract the electronic thrust gauge and the dial indicator, rotate the assembly 90 degrees, align the electronic thrust gauge with one X-direction surface of the working member, adjust the clamping platform's movement so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-bearing test rod, then reset the electronic thrust gauge, apply the dial indicator to the other X-direction surface of the working member of the standard force-bearing test rod and reset it, gradually drive the electronic thrust gauge, record the applied force values ​​and corresponding dial indicator displacement values ​​at several test points, and complete the X-direction data recording of the standard force-bearing test rod;

[0015] Step S103: retract the electronic thrust gauge and the micrometer, adjust the height and position of the machine tool spindle so that the bottom surface of the standard force check rod contacts the vertical push piece of the rotary block, adjust the movement of the clamping table so that the thrust head of the electronic thrust gauge contacts the horizontal push piece of the rotary block, then reset the electronic thrust gauge, apply the micrometer to the top surface of the action piece of the standard force check rod and reset it, gradually drive the electronic thrust gauge, record the force values ​​and corresponding micrometer displacement values ​​of several test points, where the last test point is the test point with the maximum allowable force N, and complete the data recording in the Z direction of the standard force check rod;

[0016] Step S104: Fit the recorded data of the standard stress-bearing test rod in the X and Y directions to obtain the static stiffness curves of the whole machine in the two directions; record the maximum displacement value of the standard stress-bearing test rod in the Z direction;

[0017] Step S105: simulating static stiffness curves of the standard stress-bearing test rod in two directions by software;

[0018] Step S106 : Subtract the static stiffness curve of the rod test simulation from the static stiffness curve of the entire machine to obtain the static stiffness curves of the machine tool spindle in two directions.

[0019] The third aspect is the static stiffness test method of machine tools, including:

[0020] Step S201: Adjust the height of the standard force-checking rod on the machine tool spindle so that the electronic thrust gauge is aligned with one Y-direction surface of the working member. Adjust the movement of the clamping platform so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-checking rod. Then, reset the electronic thrust gauge. Apply the dial indicator to the other Y-direction surface of the working member of the standard force-checking rod and reset it. Then, gradually drive the electronic thrust gauge to record the force values ​​and corresponding dial indicator displacement values ​​at several test points, thereby completing the data recording in the Y direction of the standard force-checking rod.

[0021] Step S202: Retract the electronic thrust gauge and the dial indicator, rotate the assembly 90 degrees, align the electronic thrust gauge with one X-direction surface of the working member, adjust the clamping platform's movement so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-bearing check rod, then reset the electronic thrust gauge, apply the dial indicator to the other X-direction surface of the working member of the standard force-bearing check rod and reset it, gradually drive the electronic thrust gauge, record the applied force values ​​and corresponding dial indicator displacement values ​​at several test points, and complete the X-direction data recording of the standard force-bearing check rod;

[0022] Step S203: retract the electronic thrust gauge and the micrometer, rotate the assembly 45 degrees, align the electronic thrust gauge with an inclined surface of the working member, adjust the movement of the clamping platform so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-bearing test rod, then reset the electronic thrust gauge, apply the micrometer to the inclined surface opposite to the working member of the standard force-bearing test rod and reset it, gradually drive the electronic thrust gauge, record the applied force values ​​and corresponding micrometer displacement values ​​at several test points, and complete the data recording in the inclined direction of the standard force-bearing test rod.

[0023] Step S204: retract the electronic thrust gauge and the micrometer, adjust the height and position of the machine tool spindle so that the bottom surface of the standard force-checking rod contacts the vertical push piece of the rotary block, adjust the movement of the clamping table so that the thrust head of the electronic thrust gauge contacts the horizontal push piece of the rotary block, then reset the electronic thrust gauge, apply the micrometer to the top surface of the action piece of the standard force-checking rod and reset it, gradually drive the electronic thrust gauge, record the force values ​​and corresponding micrometer displacement values ​​of several test points, where the last test point is the test point with the maximum allowable force N, and complete the data recording in the Z direction of the standard force-checking rod;

[0024] Step S205: Fit the recorded data of the standard stress-bearing test rod in the X, Y and inclined plane directions to obtain the static stiffness curves of the whole machine in the three directions; record the maximum displacement value of the standard stress-bearing test rod in the Z direction;

[0025] Step S206: Using software to simulate the static stiffness curves of the standard stress-bearing test rod in the three directions of X, Y, and 45 degrees.

[0026] Step S207 : Subtract the static stiffness curve of the rod test simulation from the static stiffness curve of the whole machine to obtain the static stiffness curves of the machine tool spindle in the X, Y and 45 degree directions.

[0027] Furthermore, the static stiffness curves of the machine tool spindle in the X, Y, and 45-degree directions are F1(X), F2(Y), and F3(U), respectively. The maximum allowable force of the standard force-bearing rod is N, and the maximum displacement thresholds in the three directions and the Z direction are X0, Y0, U0, and Z0, respectively.

[0028] When F1(N)<X0, F2(N)<Y0, F3(N)<U0 and the maximum displacement value in the Z direction when the applied force is N is <Z0; and (X0-F1(N)) / X0+(Y0–F2(N)) / Y0+(U0–F3(N)) / U0>P, where P is the deviation degree threshold, it is judged that the static stiffness test of the machine tool is qualified.

[0029] The beneficial effects of the present invention are as follows: the invention sets a stress-bearing check rod with a standard structure, and through the structural design of the clamping table, the static stiffness curves of the whole machine in two or three directions can be measured; then the standard stress-bearing check rod is simulated to obtain the simulated static stiffness curve of the check rod, and the static stiffness curve of the machine tool spindle is obtained by subtracting the simulated static stiffness curve of the check rod from the static stiffness curve of the whole machine; in this method, since the stress-bearing check rod is of a standard structure, the bottom is a cubic active part with a flat active surface, and a boss is formed outward on the top of the active part, which is convenient for placing the active end of the micrometer; and when the electronic thrust gauge is moving, by setting a support frame downward at the tail end of the connecting plate, the support frame can position the angle on the one hand, and on the other hand, the guide rail and the slider on the connecting plate can only slide back and forth, and the thrust gauge will not have Z-direction and lateral displacement, thereby ensuring measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a diagram of the structure of the detection tooling for Z-direction detection provided by an embodiment of the present invention;

[0031] Figure 2 yes Figure 1 A magnified view of the inspection tooling;

[0032] Figure 3 yes Figure 2 Partial details of the inspection tooling;

[0033] Figure 4 This is a diagram of the structure of the inspection tooling for Y-direction inspection provided by an embodiment of the present invention;

[0034] Figure 5 This is a structural diagram of the detection tooling for X-direction detection provided by an embodiment of the present invention;

[0035] Figure 6 is a record data table provided by an embodiment of the present invention;

[0036] Figure 7 1 is a schematic diagram of the static stiffness curve of the whole machine provided by an embodiment of the present invention;

[0037] Figure 8 Schematic diagram of a simulated static stiffness curve of a test rod provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0039] In order to illustrate the technical solution of the present invention, specific embodiments are provided below.

[0040] like Figure 1 、 2As shown in Figure 3, Figure 100 is a machine tool, and Figure 200 is a testing fixture. The static stiffness testing fixture of the machine tool provided in this embodiment includes a standard force-bearing test rod 1 for vertical installation on the main shaft of the machine tool, and also includes a mounting base 2. A rotating assembly 3 is provided on the mounting base 2. A clamping platform 5 is installed at the output end of the rotating assembly 3. An electronic thrust gauge 7 is fixed to the top of the movable side of the clamping jaws of the clamping platform 5 through a connecting plate 6. A bracket 8 is provided on the top of the fixed clamping jaws of the clamping platform 5. A rotating block 9 is installed on the bracket 8. Pushing members 10 are fixed on the two planes of the rotating block 9. The two pushing members 10 are vertically arranged. The standard force-bearing test rod 1 includes a connecting column 11 and an action member 12 formed at the bottom of the connecting column. The action member 12 is cubic. The testing fixture also includes a micrometer 4 that contacts the surface of the action member. The installation position of the micrometer 4 is not limited in this embodiment.

[0041] In this structure, the force-bearing rod is a standard design, with an upper portion serving as a connecting column for mounting to the machine tool spindle and a lower portion serving as a cubical active member. As a structure, the active member has three X, Y, and Z dimensions, each of which is flat. Furthermore, the active member 12 has an outwardly extending boss formed on its top. This boss serves as the active end of the micrometer in the Z direction.

[0042] The specific form of the rotating component 3 can have an active rotation function, such as a rotating cylinder, or can only rotate freely, such as a turntable flange, by manually rotating the angle of the clamping table.

[0043] During the propulsion process of the electronic thrust meter, due to the blocking force of the force-bearing rod and the long length of the connecting plate of the electronic thrust meter, the connecting plate will have a small deviation in the Z direction and the lateral direction, which will affect the detection accuracy. To this end, this embodiment designs a specific stable structure. Specifically, a guide rail 13 is provided at the bottom of the rear part of the connecting plate 6, and a matching slider 14 is installed on the guide rail 13. A groove plate 15 is provided at the bottom of the slider 14. A plurality of positioning grooves 16 are formed on the mounting base 2 according to angles, and the figure shows three angle directions of 0°, 45° and 90°. A matching support frame 17 is inserted between the groove plate 15 and one of the positioning grooves 16. In this structure, after the clamping platform is rotated to the required angle, the upper and lower sections of the support frame are aligned and inserted into the groove plate and the positioning groove. Since the groove plate and the positioning groove are both provided with dovetail grooves, the two sections of the support frame are dovetail blocks that match the dovetail grooves. The support frame can be used to position the angle, while the guide rails and sliders on the connecting plate can only slide forward and backward, preventing the thrust meter from moving up and down or left and right, playing a supporting role and ensuring measurement accuracy. In the figure, a baffle 18 is fixed to the end of the connecting plate 6 to prevent the slider from detaching.

[0044] For the above structure, the operation of this test fixture is as follows:

[0045] Step S101: Adjust the height of the standard force check rod on the machine tool spindle so that the electronic thrust gauge is aligned with one Y-direction surface of the working part, adjust the movement of the clamping table so that the thrust head of the electronic thrust gauge contacts the working part of the standard force check rod, then reset the electronic thrust gauge, apply the dial indicator to the other Y-direction surface of the working part of the standard force check rod and reset it, gradually drive the electronic thrust gauge, record the force values ​​and corresponding dial indicator displacement values ​​at several test points, and complete the data recording in the Y direction of the standard force check rod.

[0046] The machine tool spindle can move up and down, forward and backward, and the movable clamp of the clamping table carries the electronic thrust gauge and can move forward and backward. First, adjust the position of the standard force check rod and the movable clamp of the clamping table so that the thrust head of the electronic thrust gauge contacts a surface of the standard force check rod in the Y direction. First, adjust the electronic thrust gauge connecting plate to align with the 0° positioning groove below, such as Figure 4 The state shown. Then, insert the upper and lower ends of the support frame into the slot plate and the positioning slots. The friction between the support frame and the positioning slot is high, preventing free movement. Before testing, reset the electronic thrust gauge and dial indicator to zero. Actuate the electronic thrust gauge, select several test points, and record the applied force and corresponding dial indicator displacement at each point.

[0047] In addition, since the connection firmness of the movable clamping mouth of the connecting plate and the clamping platform cannot be fully guaranteed, in order to prevent the end of the connecting plate from deviating downward during operation, this structure has an adjustable support frame 14 installed downward at the end of the connecting plate to first support the mounting base and then operate the electronic thrust gauge.

[0048] Step S102: retract the electronic thrust gauge and the micrometer, rotate the assembly 90 degrees, align the electronic thrust gauge with one X-direction surface of the working member, adjust the movement of the clamping platform so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-bearing test rod, then reset the electronic thrust gauge, apply the micrometer to the other X-direction surface of the working member of the standard force-bearing test rod and reset it, gradually drive the electronic thrust gauge, record the applied force values ​​and corresponding micrometer displacement values ​​at several test points, and complete the data recording in the X direction of the standard force-bearing test rod.

[0049] After completing the Y direction detection in step S101, this step first retracts the support frame, retracts the electronic thrust gauge and removes the micrometer. Then, after the rotating assembly rotates 90 degrees, the connecting plate is aligned with the 90° positioning groove, as shown in the figure. Figure 5 As shown, after installing the support frame at a 90-degree angle, align the electronic thrust gauge with one X-direction surface of the working member. The subsequent process is the same as the Y-direction test. Select several test points and record the applied force and corresponding micrometer displacement at each point.

[0050] Step S103: retract the electronic thrust gauge and the micrometer, adjust the height and position of the machine tool spindle so that the bottom surface of the standard force-checking rod contacts the vertical push piece of the rotary block, adjust the movement of the clamping table so that the thrust head of the electronic thrust gauge contacts the horizontal push piece of the rotary block, then reset the electronic thrust gauge, apply the micrometer to the top surface of the action piece of the standard force-checking rod and reset it, gradually drive the electronic thrust gauge, record the force values ​​of several test points and the corresponding micrometer displacement values, where the last test point is the test point with the maximum allowable force N, and complete the data recording in the Z direction of the standard force-checking rod.

[0051] Since the electronic thrust gauge cannot output force upward, this embodiment enables the electronic thrust gauge to indirectly act on the bottom surface of the force-bearing test rod by means of a turn block and two push pieces. First, adjust the height and position of the machine tool spindle so that the bottom surface of the force-bearing test rod contacts the vertical push piece of the turn block, then turn the handle to make the movable clamp move together with the electronic thrust gauge until it contacts the horizontal push piece of the turn block. Reset the electronic thrust gauge and micrometer to zero, record the force values ​​of several test points and the corresponding micrometer displacement values, and complete the data recording in the Z direction of the standard force-bearing test rod.

[0052] Step S104 , respectively fitting the recorded data of the standard stress test rod in the X and Y directions to obtain the static stiffness curves of the whole machine in the two directions; and also recording the maximum displacement value of the standard stress test rod in the Z direction for use in the subsequent step S106 .

[0053] Step S105: Simulating static stiffness curves of the standard stress-bearing test rod in two directions through software.

[0054] Step S106 : Subtract the static stiffness curve of the rod test simulation from the static stiffness curve of the entire machine to obtain the static stiffness curves of the machine tool spindle in two directions.

[0055] As a specific example, after obtaining the recorded data in two directions, the specific recorded data is as follows: Figure 6 The static stiffness curves of the whole machine in the XY direction are obtained by least square fitting respectively, as shown in Figure 7 As shown, the static stiffness curve of the test rod simulation is as follows Figure 8 shown.

[0056] As can be seen, 1) on-site measurements show that the rigidity of the entire machine tool in the X-direction is approximately 1.5 μm / N, and in the Y-direction is 1.4 μm / N, forming a linear distribution. 2) Simulation results for the load-bearing rod body show that the load-bearing rod body has a linear distribution of approximately 0.4 μm / N in the X and Y directions. 3) The calculated rigidity of the machine tool in the X and Y directions is approximately 1 μm / N. 4) On-site measurements show that the rigidity of the machine tool in the Z-direction is good. 5) Simulation results for the load-bearing rod body show that the rigidity in the Z-axis direction is very high, and its deformation is negligible. Therefore, it can be inferred that the deformation in the Z-direction is very small, and no curve fitting is required.

[0057] In this method, the static stiffness curves of the bed spindle in the XY direction can be obtained as F1(X) and F2(Y), the maximum allowable force of the standard force-bearing rod is N, and the maximum displacement thresholds in the XY direction and the Z direction are X0, Y0 and Z0 respectively;

[0058] When F1(N)<X0, F2(N)<Y0 and the maximum displacement value in the Z direction when the applied force is N is<Z0; and (X0-F1(N)) / X0+(Y0–F2(N)) / Y0>P1, where P1 is the deviation threshold when measured in two directions, the machine tool static stiffness test is judged to be qualified.

[0059] In addition, this embodiment also provides another detection method, including the following steps:

[0060] In a third aspect, the machine tool static stiffness testing method comprises:

[0061] Step S201: Adjust the height of the standard force-checking rod on the machine tool spindle so that the electronic thrust gauge is aligned with one Y-direction surface of the working member. Adjust the movement of the clamping platform so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-checking rod. Then, reset the electronic thrust gauge. Apply the dial indicator to the other Y-direction surface of the working member of the standard force-checking rod and reset it. Then, gradually drive the electronic thrust gauge to record the force values ​​and corresponding dial indicator displacement values ​​at several test points, thereby completing the data recording in the Y direction of the standard force-checking rod.

[0062] Step S202: Retract the electronic thrust gauge and the dial indicator, rotate the assembly 90 degrees, align the electronic thrust gauge with one X-direction surface of the working member, adjust the clamping platform's movement so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-bearing check rod, then reset the electronic thrust gauge, apply the dial indicator to the other X-direction surface of the working member of the standard force-bearing check rod and reset it, gradually drive the electronic thrust gauge, record the applied force values ​​and corresponding dial indicator displacement values ​​at several test points, and complete the X-direction data recording of the standard force-bearing check rod;

[0063] Step S203: retract the electronic thrust gauge and the micrometer, rotate the assembly 45 degrees, align the electronic thrust gauge with an inclined surface of the working member, adjust the movement of the clamping platform so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-bearing test rod, then reset the electronic thrust gauge, apply the micrometer to the inclined surface opposite to the working member of the standard force-bearing test rod and reset it, gradually drive the electronic thrust gauge, record the applied force values ​​and corresponding micrometer displacement values ​​at several test points, and complete the data recording in the inclined direction of the standard force-bearing test rod.

[0064] Step S204: retract the electronic thrust gauge and the micrometer, adjust the height and position of the machine tool spindle so that the bottom surface of the standard force-checking rod contacts the vertical push piece of the rotary block, adjust the movement of the clamping table so that the thrust head of the electronic thrust gauge contacts the horizontal push piece of the rotary block, then reset the electronic thrust gauge, apply the micrometer to the top surface of the action piece of the standard force-checking rod and reset it, gradually drive the electronic thrust gauge, record the force values ​​and corresponding micrometer displacement values ​​of several test points, where the last test point is the test point with the maximum allowable force N, and complete the data recording in the Z direction of the standard force-checking rod;

[0065] Step S205: Fit the recorded data of the standard stress test rod in the X, Y, and inclined directions to obtain the static stiffness curves of the whole machine in the three directions. This step also uses the least squares fitting method; in addition, the maximum displacement value of the standard stress test rod in the Z direction is recorded and used in the subsequent step S207;

[0066] Step S206: Using software to simulate the static stiffness curves of the standard stress-bearing test rod in the three directions of X, Y, and 45 degrees.

[0067] Step S207 : Subtract the static stiffness curve of the rod test simulation from the static stiffness curve of the whole machine to obtain the static stiffness curves of the machine tool spindle in the X, Y and 45 degree directions.

[0068] In this method, the inclined direction detection of the working part is added, the detection range is wider, and it can better simulate the operating conditions of the machine tool.

[0069] The static stiffness curves of the machine tool spindle in the X, Y, and 45-degree directions are F1(X), F2(Y), and F3(U), respectively. The maximum allowable force of the standard force-bearing rod is N, and the maximum displacement thresholds in the three directions and the Z direction are X0, Y0, U0, and Z0, respectively.

[0070] When F1(N)<X0, F2(N)<Y0, F3(N)<U0 and the maximum displacement value in the Z direction when the applied force is N is <Z0; and (X0-F1(N)) / X0+(Y0–F2(N)) / Y0+(U0–F3(N)) / U0>P, where P is the deviation degree threshold, it is judged that the static stiffness test of the machine tool is qualified.

[0071] Although the maximum displacement value in the Z direction when the applied force is N is basically negligible, it is still necessary to set the maximum displacement threshold Z0. If it is greater than or equal to Z0, the static stiffness test of the machine tool is directly deemed to be unqualified.

[0072] If F1(N), F2(N), and F3(N) are all less than the set maximum displacement thresholds under maximum applied force N, the basic condition for a qualified test is met. Furthermore, this embodiment further determines the degree of deviation between the maximum displacement values ​​in the three directions and the corresponding maximum displacement thresholds. If F1(N), F2(N), and F3(N) are all close to X0, Y0, and U0, this indicates that the degree of deviation in the three directions is relatively small, indicating that the machine tool spindle may be prone to fatigue after long-term operation, posing a potential risk. Therefore, the machine tool static stiffness test is also considered unqualified in this case, further improving accuracy.

[0073] On the other hand, since this method also adds 45-degree direction data detection, for each point of measurement, under normal circumstances, This method can be used to check whether the fitted curve is accurate. If the error is large, for example, if several points are taken, If the set value is exceeded, retesting and curve fitting are required to further ensure the accuracy of the test data.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A machine tool static stiffness test fixture, characterized in that:

7. The swiftly and minutely adjusting device for a wood-planer working table as claimed in claim 1, wherein said linking rod and said adjusting base are pivotally connected to each other with a bolt, and said bolt has a round shank to contact with said linking rod. said linking rod has a round shank to contact with said linking rod.

2. The machine tool static stiffness test fixture according to claim 1, characterized in that: The groove plate and the positioning groove are both provided with dovetail grooves, and the two sections of the support frame are dovetail blocks matching the dovetail grooves.

3. The machine tool static stiffness testing fixture as claimed in claim 2, characterized in that: A baffle is fixed at the end of the connecting plate.

4. A method for testing static stiffness of a machine tool, characterized in that: The testing method is applied to the machine tool static stiffness testing fixture according to any one of claims 1 to 3, and the testing method comprises the following steps: Step S101: Adjust the height of the standard force-checking rod on the machine tool spindle so that the electronic thrust gauge is aligned with one Y-direction surface of the working member. Adjust the movement of the clamping platform so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-checking rod. Then, reset the electronic thrust gauge. Apply the dial indicator to the other Y-direction surface of the working member of the standard force-checking rod and reset it. Then, gradually drive the electronic thrust gauge to record the force values ​​and corresponding dial indicator displacement values ​​at several test points, thereby completing the data recording in the Y direction of the standard force-checking rod. Step S102: Retract the electronic thrust gauge and the dial indicator, rotate the assembly 90 degrees, align the electronic thrust gauge with one X-direction surface of the working member, adjust the clamping platform's movement so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-bearing test rod, then reset the electronic thrust gauge, apply the dial indicator to the other X-direction surface of the working member of the standard force-bearing test rod and reset it, gradually drive the electronic thrust gauge, record the applied force values ​​and corresponding dial indicator displacement values ​​at several test points, and complete the X-direction data recording of the standard force-bearing test rod; Step S103: retract the electronic thrust gauge and the micrometer, adjust the height and position of the machine tool spindle so that the bottom surface of the standard force check rod contacts the vertical push piece of the rotary block, adjust the movement of the clamping table so that the thrust head of the electronic thrust gauge contacts the horizontal push piece of the rotary block, then reset the electronic thrust gauge, apply the micrometer to the top surface of the action piece of the standard force check rod and reset it, gradually drive the electronic thrust gauge, record the force values ​​and corresponding micrometer displacement values ​​of several test points, where the last test point is the test point with the maximum allowable force N, and complete the data recording in the Z direction of the standard force check rod; Step S104: Fit the recorded data of the standard stress-bearing test rod in the X and Y directions to obtain the static stiffness curves of the whole machine in the two directions; record the maximum displacement value of the standard stress-bearing test rod in the Z direction; Step S105: simulating static stiffness curves of the standard stress-bearing test rod in two directions by software; Step S106 : Subtract the static stiffness curve of the rod test simulation from the static stiffness curve of the entire machine to obtain the static stiffness curves of the machine tool spindle in two directions.

5. A method for testing static stiffness of a machine tool, characterized in that: The testing method is applied to the machine tool static stiffness testing fixture according to any one of claims 1 to 3, and the testing method comprises: Step S201: Adjust the height of the standard force-checking rod on the machine tool spindle so that the electronic thrust gauge is aligned with one Y-direction surface of the working member. Adjust the movement of the clamping platform so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-checking rod. Then, reset the electronic thrust gauge. Apply the dial indicator to the other Y-direction surface of the working member of the standard force-checking rod and reset it. Then, gradually drive the electronic thrust gauge to record the force values ​​and corresponding dial indicator displacement values ​​at several test points, thereby completing the data recording in the Y direction of the standard force-checking rod. Step S202: Retract the electronic thrust gauge and the dial indicator, rotate the assembly 90 degrees, align the electronic thrust gauge with one X-direction surface of the working member, adjust the clamping platform's movement so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-bearing check rod, then reset the electronic thrust gauge, apply the dial indicator to the other X-direction surface of the working member of the standard force-bearing check rod and reset it, gradually drive the electronic thrust gauge, record the applied force values ​​and corresponding dial indicator displacement values ​​at several test points, and complete the X-direction data recording of the standard force-bearing check rod; Step S203: retract the electronic thrust gauge and the dial indicator, rotate the assembly 45 degrees, align the electronic thrust gauge with an inclined surface of the working member, adjust the clamping platform's movement so that the thrust head of the electronic thrust gauge contacts the working member of the standard force-bearing test rod, then reset the electronic thrust gauge, apply the dial indicator to the inclined surface opposite the working member of the standard force-bearing test rod and reset it, gradually drive the electronic thrust gauge, record the applied force values ​​and corresponding dial indicator displacement values ​​at several test points, and complete the data recording in the inclined direction of the standard force-bearing test rod; Step S204: retract the electronic thrust gauge and the micrometer, adjust the height and position of the machine tool spindle so that the bottom surface of the standard force-checking rod contacts the vertical push piece of the rotary block, adjust the movement of the clamping table so that the thrust head of the electronic thrust gauge contacts the horizontal push piece of the rotary block, then reset the electronic thrust gauge, apply the micrometer to the top surface of the action piece of the standard force-checking rod and reset it, gradually drive the electronic thrust gauge, record the force values ​​and corresponding micrometer displacement values ​​of several test points, where the last test point is the test point with the maximum allowable force N, and complete the data recording in the Z direction of the standard force-checking rod; Step S205: Fit the recorded data of the standard stress-bearing test rod in the X, Y and inclined plane directions to obtain the static stiffness curves of the whole machine in the three directions; record the maximum displacement value of the standard stress-bearing test rod in the Z direction; Step S206: Using software to simulate the static stiffness curves of the standard stress-bearing test rod in the three directions of X, Y, and 45 degrees. Step S207 : Subtract the static stiffness curve of the rod test simulation from the static stiffness curve of the whole machine to obtain the static stiffness curves of the machine tool spindle in the X, Y and 45 degree directions.

6. The machine tool static stiffness testing method according to claim 5, characterized in that: The static stiffness curves of the machine tool spindle in the X, Y, and 45-degree directions are F1(X), F2(Y), and F3(U), respectively. The maximum allowable force of the standard force-bearing rod is N, and the maximum displacement thresholds in the three directions and the Z direction are X0, Y0, U0, and Z0, respectively. When F1(N)<X0, F2(N)<Y0, F3(N)<U0 and the maximum displacement value in the Z direction when the applied force is N is <Z0; and (X0-F1(N)) / X0+(Y0–F2(N)) / Y0+(U0–F3(N)) / U0>P, where P is the deviation degree threshold, it is judged that the static stiffness test of the machine tool is qualified.

Images