Inertial static and dynamic force composite loading system

Abstract

The application discloses an inertial static and dynamic force composite loading system, and relates to the field of loading control systems.The system comprises an air control box, a multifunctional acquisition card, a piezoelectric driver, a machine tool workbench, a loading tool, an air cylinder and a piezoelectric dynamic loading device.The piezoelectric dynamic loading device further comprises a base, a linear bearing, an outer cylinder, a counterweight frame, a piezoelectric actuator, a front plate, a pre-tightening nut, a force sensor, an insulating gasket and a loading head.The inertial static and dynamic force composite loading system adopts the above structure, utilizes the piezoelectric actuator with high rigidity and high response, and combines the piezoelectric dynamic loading device with the pneumatic loading device, so that the static and dynamic force composite loading of the numerical control machine tool is realized, the dynamic frequency range and the dynamic force size of the dynamic force are improved, the approximate simulation of the actual cutting load is completed, and technical support is provided for the measurement and evaluation and research of the reliability and other indexes of the numerical control machine tool.

Description

Technical Field

[0001] The present invention relates to the technical field of loading control systems, and in particular to an inertial static and dynamic force composite loading system. Background Art

[0002] In the actual application of CNC machine tools, the cutting loads on the spindle and table consist of two components: static average cutting force and dynamic cutting force. To conduct test evaluation and research on CNC machine tool reliability, accuracy retention, and accelerated degradation, a loading device is required to approximately simulate the load conditions under actual CNC machine tool operating conditions for environmental and safety reasons.

[0003] Existing loading systems typically use power devices such as electric cylinders, pneumatic cylinders, or hydraulic cylinders to load the spindles of CNC machine tools. These devices can effectively simulate the static portion of actual cutting forces by adjusting motor torque, gas, or oil pressure. However, they suffer from a common problem, namely, they cannot effectively simulate the dynamic portion of actual cutting forces. Even if dynamic forces can be generated by adjusting motor torque, gas, or oil pressure, their adjustment frequency is too low, typically less than 10 Hz, and the dynamic force range is too small to simulate the actual load conditions of high-speed spindles, let alone conduct test scenarios requiring high-frequency dynamic forces, including accelerated degradation tests. Summary of the Invention

[0004] The purpose of the present invention is to provide an inertial static and dynamic force composite loading system. By utilizing a high-rigidity and high-response piezoelectric actuator, a piezoelectric dynamic loading device is designed to be combined with a pneumatic loading device to achieve static and dynamic load composite loading of CNC machine tools, complete an approximate simulation of the actual cutting load, and overcome the defects of the prior art such as low dynamic frequency of the loading force and small dynamic force range.

[0005] To achieve the above-mentioned objectives, the present invention provides an inertial static and dynamic force composite loading system, comprising a machine tool worktable and a loading fixture arranged on the machine tool worktable, wherein the loading fixture is provided with a cylinder, the cylinder is connected to an air control box via an air pipe, the air control box is connected to a control acquisition box via an air control cable, the control acquisition box is connected to a piezoelectric driver via a drive control line, the piezoelectric driver is connected to a piezoelectric dynamic loading device via a piezoelectric actuator cable, and the piezoelectric dynamic loading device is screwed to the cylinder.

[0006] Preferably, the piezoelectric dynamic loading device includes a base and an outer cylinder arranged on the base, a piezoelectric actuator is arranged in the outer cylinder, one end of the piezoelectric actuator is connected to the counterweight frame through a bolt, and linear bearings are provided at both ends of the counterweight frame. The other end of the outer cylinder is connected to the front plate, the front plate is connected to one end of the pre-tightening nut, and the other end of the pre-tightening nut is connected to a loading head, a force sensor is arranged between the loading head and the pre-tightening nut, and insulating gaskets are provided on both sides of the force sensor.

[0007] Preferably, the outer wall of the linear bearing abuts against the inner wall of the outer cylinder.

[0008] Preferably, the piezoelectric actuator is connected to the piezoelectric driver, and the piezoelectric driver is connected to the piezoelectric control interface of the control acquisition box through the drive control line. The input voltage of the piezoelectric driver is adjusted by the D / A module in the control acquisition box, thereby controlling the telescopic amplitude of the piezoelectric actuator, so that the counterweight frame installed on the piezoelectric actuator generates reciprocating motion under the support of the linear bearing, thereby generating inertial force.

[0009] Preferably, the counterweight frame is provided with two counterweight mounting holes, and the counterweight mounting holes are used to install counterweights of different masses as needed to adjust the magnitude of the inertial force.

[0010] Preferably, the base is connected to the end of the cylinder through a thread, and the static force generated by the cylinder is transmitted to the front plate through the base and the outer cylinder. The dynamic force generated by the reciprocating motion of the piezoelectric actuator and the counterweight also acts on the front plate. The dynamic force and the static force are superimposed on the front plate to form a static-dynamic composite loading force, and finally the composite loading force is applied to the spindle of the CNC machine tool through the loading head.

[0011] Preferably, the force sensor is a piezoelectric force sensor, which is connected to the force signal input interface of the control acquisition box through a force sensor signal line.

[0012] Preferably, a display, an industrial computer and a multi-function acquisition card are provided in the control acquisition box. The digital IO channel of the multi-function acquisition card controls the solenoid valve in the air control box, thereby controlling the extension and contraction of the cylinder. The D / A channel of the multi-function acquisition card controls the reciprocating motion of the piezoelectric actuator by outputting an analog voltage. The A / D channel is used to collect the composite loading force measured by the force sensor.

[0013] Beneficial effects of the present invention:

[0014] (1) The present invention uses a high-rigidity and high-response piezoelectric actuator to drive the counterweight to reciprocate and generate inertial force to generate dynamic force, which can generate a dynamic force with a frequency range of 0.3KHz-1KHz and a maximum dynamic load of 600N, effectively solving the defects of low dynamic frequency of loading force and small dynamic force range in the prior art.

[0015] (2) The present invention uses a piezoelectric force sensor to measure the composite loading force. Since the piezoelectric force sensor has much greater stiffness than the traditional strain force sensor, it can effectively improve the overall stiffness of the loading system and solve the problem of low dynamic force caused by low stiffness.

[0016] (3) The design structure of the piezoelectric dynamic loading device in the present invention can superimpose the dynamic force and the static force at the front plate, so that static loading and dynamic loading can be carried out simultaneously, achieving an approximate simulation of the actual cutting load, and providing technical support for the evaluation and research of CNC machine tool reliability, precision retention and accelerated degradation tests.

[0017] Therefore, the present invention adopts an inertial static and dynamic force composite loading system of the above structure. By using a piezoelectric actuator with high stiffness and high response to design a piezoelectric dynamic loading device, and combining it with a pneumatic loading device, it realizes the static and dynamic load composite loading of the CNC machine tool, completes the approximate simulation of the actual cutting load, and overcomes the defects of the existing technology such as low dynamic frequency of the loading force and small dynamic force range.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of an inertial static and dynamic force composite loading system of the present invention;

[0020] Figure 2 Schematic diagram of the structure of the piezoelectric dynamic loading device;

[0021] Figure 3 The figure is a schematic diagram of a composite loading example obtained by using an inertial static and dynamic force composite loading system of the present invention.

[0022] Reference numerals

[0023] 1. Piezoelectric driver; 2. Drive control line; 3. Industrial computer; 4. Display; 5. Control acquisition box; 6. Multi-function acquisition card; 7. Air control cable; 8. Air control box; 9. Air pipe; 10. Loading fixture; 11. Cylinder; 12. Piezoelectric dynamic loading device; 13. Machine tool worktable; 14. Force sensor signal line; 15. Piezoelectric actuator cable; 16. Base; 17. Linear bearing; 18. Outer cylinder; 19. Counterweight frame; 20. Piezoelectric actuator; 21. Front plate; 22. Pre-tightening nut; 23. Force sensor; 24. Loading head; 25. Insulation gasket; 26. Counterweight mounting hole. DETAILED DESCRIPTION

[0024] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0025] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0026] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0027] Example

[0028] like Figure 1-2As shown, an inertial static and dynamic force composite loading system, including a machine tool worktable 13 and a loading tool 10 arranged on the machine tool worktable 13, the loading tool 10 is provided with a cylinder 11, the inlet and outlet of the cylinder 11 is connected with the electromagnetic valve in the air control box 8 through the air pipe 9, the air control box 8 is connected with the control interface of the control and collection box 5 through the air control cable 7, the extension and contraction of the cylinder 11 is controlled, the size of the static force of the composite loading system is adjusted by adjusting the output air pressure of the pressure reducing valve in the air control box 8. The control and collection box 5 is connected with the piezoelectric driver 1 through the driving control line 2, the piezoelectric driver 1 is connected with the piezoelectric dynamic loading device 12 through the piezoelectric actuator cable 15, the piezoelectric dynamic loading device 12 is screwed with the cylinder 11; the piezoelectric dynamic loading device 12 includes a base 16 and an outer cylinder 18 arranged on the base 16, the outer cylinder 18 is provided with a piezoelectric actuator 20, one end of the piezoelectric actuator 20 is connected with the counterweight frame 19 through a bolt, the two ends of the counterweight frame 19 are provided with linear bearings 17, the other end of the outer cylinder 18 is connected with a front plate 21, the front plate 21 is connected with one end of a pre-tightening nut 22, the other end of the pre-tightening nut 22 is connected with a loading head 24, a force sensor 23 is arranged between the loading head 24 and the pre-tightening nut 22, insulating gaskets 25 are arranged on the two sides of the force sensor 23; the outer wall of the linear bearing 17 abuts against the inner wall of the outer cylinder 18.

[0029] The piezoelectric actuator 20 is connected with the piezoelectric driver 1, the piezoelectric driver 1 is connected with the piezoelectric control interface of the control and collection box 5 through the driving control line 2, the input voltage of the piezoelectric driver 1 is adjusted through the D / A module in the control and collection box 5, so as to control the extension and contraction amplitude of the piezoelectric actuator 20, the counterweight frame 19 installed on the piezoelectric actuator 20 reciprocates under the support of the linear bearing 17, so as to generate inertial force; the frequency and size of the dynamic force of the composite loading system are adjusted by adjusting the frequency and amplitude of the input voltage of the piezoelectric driver 1; two counterweight mounting holes 26 are arranged on the counterweight frame 19, different quality counterweights can be installed in the counterweight mounting holes 26 according to needs, so as to adjust the size of the inertial force; the base 16 is connected with the end of the cylinder 11 through threads, the static force generated by the cylinder 11 is transmitted to the front plate 21 through the base 16 and the outer cylinder 18, the dynamic force generated by the reciprocating movement of the piezoelectric actuator 20 and the counterweight also acts on the front plate 21, the dynamic force and the static force are superimposed at the front plate 21 to form a static and dynamic composite loading force, finally the composite loading force is applied to the main shaft of the numerical control machine tool through the loading head 24.

[0030] The force sensor 23 is a piezoelectric force sensor, which is connected to the force signal input interface of the control acquisition box 5 through the force sensor signal line 14; the control acquisition box 5 is equipped with a display 4, an industrial computer 3 and a multi-function acquisition card 6. The digital IO channel of the multi-function acquisition card 6 controls the solenoid valve in the air control box 8, thereby controlling the extension and contraction of the cylinder 11. The D / A channel of the multi-function acquisition card 6 controls the reciprocating motion of the piezoelectric actuator 20 by outputting an analog voltage. The A / D channel is used to collect the composite loading force measured by the force sensor 23.

[0031] like Figure 3 The figure shows a schematic diagram of a composite loading example obtained by using an inertial static and dynamic force composite loading system of the present invention. In this loading example, the static force is 1530N, the dynamic force is 80N, and the dynamic force frequency is 800Hz. It can be seen from the figure that the inertial static and dynamic force composite loading system provided by the present invention can approximately simulate the load conditions under the actual working conditions of CNC machine tools.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An inertial static and dynamic force composite loading system, characterized by: The invention comprises a machine tool workbench and a loading fixture provided on the machine tool workbench, wherein the loading fixture is provided with a cylinder, the cylinder is connected to an air control box via an air pipe, the air control box is connected to a control acquisition box via an air control cable, the control acquisition box is connected to a piezoelectric driver via a drive control line, the piezoelectric driver is connected to a piezoelectric dynamic loading device via a piezoelectric actuator cable, and the piezoelectric dynamic loading device is screwed to the cylinder; The piezoelectric dynamic loading device includes a base and an outer cylinder arranged on the base, a piezoelectric actuator is arranged in the outer cylinder, one end of the piezoelectric actuator is connected to the counterweight frame by a bolt, and both ends of the counterweight frame are provided with linear bearings, the other end of the outer cylinder is connected to the front plate, the front plate is connected to one end of the pre-tightening nut, and the other end of the pre-tightening nut is connected to a loading head, a force sensor is arranged between the loading head and the pre-tightening nut, and insulating gaskets are provided on both sides of the force sensor; The piezoelectric actuator is connected to the piezoelectric driver, and the piezoelectric driver is connected to the piezoelectric control interface of the control acquisition box via the drive control line. The input voltage of the piezoelectric driver is adjusted by the D / A module in the control acquisition box, thereby controlling the expansion and contraction range of the piezoelectric actuator, so that the counterweight frame mounted on the piezoelectric actuator generates reciprocating motion under the support of the linear bearing, thereby generating inertial force; The base is connected to the end of the cylinder through a thread. The static force generated by the cylinder is transmitted to the front plate through the base and the outer cylinder. The dynamic force generated by the reciprocating motion of the piezoelectric actuator and the counterweight also acts on the front plate. The dynamic force and the static force are superimposed on the front plate to form a static-dynamic composite loading force. Finally, the composite loading force is applied to the spindle of the CNC machine tool through the loading head.

2. The inertial static and dynamic combined loading system according to claim 1, characterized in that: The outer wall of the linear bearing abuts against the inner wall of the outer cylinder.

3. The inertial static and dynamic combined loading system according to claim 1, characterized in that: The counterweight frame is provided with two counterweight mounting holes, and the counterweight mounting holes are used to mount counterweights of different masses as required to adjust the magnitude of the inertial force.

4. The inertial static and dynamic combined loading system according to claim 1, characterized in that: The force sensor is a piezoelectric force sensor, which is connected to the force signal input interface of the control acquisition box through a force sensor signal line.

5. The inertial static and dynamic combined loading system according to claim 1, characterized in that: The control and acquisition box is equipped with a display, an industrial computer and a multi-function acquisition card. The digital IO channel of the multi-function acquisition card controls the solenoid valve in the air control box, thereby controlling the extension and contraction of the cylinder. The D / A channel of the multi-function acquisition card controls the reciprocating motion of the piezoelectric actuator by outputting an analog voltage. The A / D channel is used to collect the composite loading force measured by the force sensor.

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