An eight-point locking device and method for repeated locking of test quality

Abstract

An eight-point locking device for repeated locking of test mass is disclosed. This invention relates to a locking device that addresses the problems of inaccurate locking position and uneven locking force in existing test mass locking mechanisms. The invention features symmetrical locking devices on both sides of the test mass. Each locking device includes a transmission mechanism, an actuator, and a lead screw assembly. The transmission mechanism is connected to the actuator via the lead screw assembly. This invention has a simple structure and achieves stable locking and releasing. The invention incorporates adjustable links at both ends of the locking mechanism to adjust the locking position and locking force of the test mass, ensuring accurate locking position during launch and avoiding damage to the test mass surface and disturbances during release caused by inconsistent locking forces at each locking point. This invention belongs to the field of aerospace technology.

Description

Technical Field

[0001] The invention relates to a locking device and a locking method, and in particular to an eight-point locking device and a locking method for testing quality and repeated locking. The invention belongs to the field of aerospace technology. Background Art

[0002] Gravitational waves are matter waves that transmit energy in the form of gravitational radiation. Their proposal has proposed a new means for detecting nature. However, due to the very small amplitude of gravitational waves, they are difficult to measure and detect. In the 1990s, the European Space Agency and NASA jointly proposed the space laser interferometer gravitational wave detection project - the LISA program. The space gravitational wave detection light source emits lasers, which are reflected by the surface of the test mass (TM) and are received by the receiver. When the gravitational waves pass through the optical path, they cause changes in the light. The changes are received by the receiver and the existence of gravitational waves can be detected. However, gravitational waves have a low frequency and small amplitude, which places strict requirements on the accuracy of the detection system. Therefore, for the testing quality of core components, it is required to be locked, released and captured accurately and without disturbance.

[0003] The existing domestic locking mechanism for test mass mainly adopts a four-rod locking solution, but because its driving mode is connecting rod drive, it is difficult to ensure the uniform speed and slowness of the mechanism when locking and releasing the test mass, which inevitably brings a certain impact on the test quality. At the same time, the existing domestic locking mechanism does not have an adjustable link in the actuator (locking rod), which can easily lead to inaccurate locking position of the test mass and uneven locking force. (Related literature on prior art: Li Huadong. Design and analysis of inertial sensor test mass locking and release mechanism [D]. University of Chinese Academy of Sciences, 2020.) Summary of the invention

[0004] In order to solve the problem that the locking position of the test mass is inaccurate and the locking force is uneven when the test mass locking mechanism completes the test mass locking, the present invention further proposes an eight-point locking device and method for repeated locking of the test mass.

[0005] The technical solution adopted by the present invention to solve the above problems is:

[0006] The test mass of the present invention is provided with a locking device symmetrically on both sides, and each locking device comprises a transmission mechanism, an actuator and a screw assembly, and the transmission mechanism is connected to the actuator through the screw assembly.

[0007] Furthermore, the transmission mechanism includes an ultrasonic motor and a gear reducer assembly, the output shaft of the ultrasonic motor is fixedly connected to the input end of the gear reducer assembly, and the output end of the gear reducer assembly is connected to the screw assembly.

[0008] Furthermore, the gear reducer assembly includes a positioning nut, a deep groove ball bearing, a gear shaft bearing, an elastic retaining ring, a secondary gear reducer, a screw bearing and a nut support cover, the secondary gear reducer includes a primary gear shaft, a primary pinion, a primary gear, a secondary gear shaft, a secondary pinion and a secondary gear, the output shaft of the ultrasonic motor is fixedly connected to the primary pinion through a positioning nut and a deep groove ball bearing, the primary pinion is meshed with the secondary gear, the secondary pinion and the secondary gear are mounted on the secondary gear shaft, both ends of the secondary gear shaft are sequentially mounted with elastic retaining rings and gear shaft bearings from the inside to the outside, the secondary pinion is meshed with the primary gear, the primary gear is mounted on the primary gear shaft, the output end of the primary gear shaft is connected to the screw assembly through a screw bearing, and the nut support cover is mounted on the positioning nut and the screw bearing.

[0009] Furthermore, the inner wall of the primary gear shaft is provided with an internal thread for connecting the screw assembly.

[0010] Furthermore, the screw rod assembly includes a screw rod and a connecting seat, the upper end of the screw rod is threadedly connected to the internal thread of the lower end of the first-stage gear shaft, and the lower end of the screw rod is connected to the middle part of the upper surface of the connecting seat and is formed as one piece.

[0011] Furthermore, the actuator comprises a flexible end actuator and a rigid end actuator, and the flexible end actuator and the rigid end actuator are respectively located on two sides of the test mass.

[0012] Furthermore, the flexible end actuator includes an adjustable end cover, a large disk, a disc spring, four push rods, and a strain type pressure sensor. The large disk is respectively provided with four mounting holes for cooperating with the push rods. The lower end of each push rod is inserted into a corresponding mounting hole. A limiting ring is provided on the upper part of each push rod. The disc spring is sleeved on the push rod and is located between the upper surface of the limiting ring and the lower surface of the adjustable end cover. The adjustable end cover is threadedly connected to the upper end of the push rod, and a strain type pressure sensor is provided on the lower part of each push rod.

[0013] Furthermore, the rigid end actuator includes an adjustable end cover, a large disk, a disc spring, four push rods and a strain type pressure sensor. The large disk is respectively provided with four mounting holes for cooperating with the push rods. The lower end of each push rod is inserted into a corresponding mounting hole. A limiting ring is provided on the upper part of each push rod. The disc spring is mounted on the push rod and is located between the lower surface of the limiting ring and the bottom plate of the mounting hole. The adjustable end cover is threadedly connected to the upper end of the push rod, and a strain type pressure sensor is provided on the lower part of each push rod.

[0014] Furthermore, the inner wall of each mounting hole is provided with a limiting groove for mounting a limiting ring, and the outer edge of the limiting ring is provided with a protrusion matching with the limiting groove.

[0015] Furthermore, a hemispherical protrusion is provided at the lower end of each of the push rods.

[0016] The beneficial effects of the present invention are:

[0017] 1. The driving mode of the present invention adopts an ultrasonic motor with a reducer, which can well control the slow and uniform locking and releasing of the test mass of the mechanism, avoiding the impact of this process on the test mass, ensuring that the mechanism will not cause excessive damage to its surface when locking the test mass, and at the same time, when releasing the test mass, it will not cause unnecessary disturbance due to excessive changes in the release speed;

[0018] 2. The present invention introduces corresponding adjustable links in the locking mechanisms at both ends of the test mass. Through different installation methods of the push rods in the flexible end actuator and the rigid end actuator, the locking force of the push rod can be effectively adjusted, so as to adjust the locking position and locking force of the test mass respectively, thereby ensuring the accurate locking position of the test mass during the launch process, and avoiding the damage to the surface of the test mass caused by the mechanism due to the inconsistent locking force of each locking point and the disturbance caused by the release of the test mass.

[0019] 3. The present invention uses an ultrasonic motor as a power source and is driven by friction, which will not cause magnetic field interference to the inertial sensor, and will not generate magnetic torque inside the test mass to affect the stability of the test mass;

[0020] 4. The present invention utilizes the 8-point locking method of the four push rods on both sides of the test mass to achieve high-precision movement of the locking push rods. At the same time, the limit rings arranged on the push rods can prevent the push rods from rotating, thereby improving the locking reliability of the locking mechanism for the test mass.

[0021] 5. The present invention provides a stable low-disturbance test mass locking device with compact structural layout, small mechanism volume, small occupied space, simple structure, avoiding over-positioning, and achieving stable locking and release. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the overall structural appearance diagram of the present invention;

[0023] Figure 2 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 3 It is a schematic diagram of the transmission mechanism structure of the present invention;

[0025] Figure 4 It is a structural diagram of a two-stage gear reducer;

[0026] Figure 5 It is a structural schematic diagram of the screw rod assembly;

[0027] Figure 6It is a schematic diagram of the structure of the actuator of the present invention;

[0028] Figure 7 is a cross-sectional view of the flexible end actuator;

[0029] Figure 8 It is a cross-sectional view of the rigid end actuator. DETAILED DESCRIPTION

[0030] Specific implementation method: Figure 1 As shown, the test mass 4 is installed in the electrode frame 5, the two ends of the electrode frame 5 are respectively connected to the base 6, the actuator 2 is located in the base 6, the two locking mechanisms are symmetrically arranged along the test mass 4, each side of the locking mechanism is provided with four locking push rods, and the mechanisms on both sides work together to achieve eight-point locking of the test mass.

[0031] like Figure 2 As shown, each of the locking devices comprises a transmission mechanism 1, an actuator 2 and a screw assembly 3, and the transmission mechanism 1 is connected to the actuator 2 via the screw assembly 3;

[0032] like Figure 3 , Figure 4 As shown, the transmission mechanism 1 includes an ultrasonic motor 1-1 and a gear reducer assembly, the output shaft of the ultrasonic motor 1-1 is fixedly connected to the input end of the gear reducer assembly, and the output end of the gear reducer assembly is connected to the screw assembly 3. The ultrasonic motor 1-1 uses the inverse piezoelectric effect to achieve precise control of the stator, and has the advantages of high precision, high resolution, good stability, etc. If there is no non-magnetization design requirement, the ultrasonic motor 1-1 can be replaced by an ordinary servo motor.

[0033] The gear reducer assembly includes a positioning nut 1-2, a deep groove ball bearing 1-3, a gear shaft bearing 1-4, an elastic retaining ring 1-5, a secondary gear reducer 1-6, a screw bearing 1-7 and a nut support cover 1-9; the secondary gear reducer 1-6 includes a primary gear shaft 1-6-1, a primary pinion 1-6-2, a primary large gear 1-6-3, a secondary gear shaft 1-6-4, a secondary pinion 1-6-5 and a secondary large gear 1-6-6, the output shaft of the ultrasonic motor 1-1 is fixedly connected to the primary pinion 1-6-2 through the positioning nut 1-2 and the deep groove ball bearing 1-3, transmitting and amplifying the motor torque, the primary pinion 1-6-2 and the secondary large gear 1-6-6 are meshed, and the secondary pinion 1-6-5 and the secondary large gear 1-6-6 are sleeved on the secondary gear shaft 1 -6-4, both ends of the secondary gear shaft 1-6-4 are sequentially mounted with elastic retaining rings 1-5 and gear shaft bearings 1-4 from the inside to the outside, which are used to fix the gear shaft and reduce rotational friction. The secondary small gear 1-6-5 is meshed with the primary large gear 1-6-3, and the primary large gear 1-6-3 is mounted on the primary gear shaft 1-6-1. The output end of the primary gear shaft 1-6-1 is connected to the screw 3-1 of the screw assembly 3 through the screw bearing 1-7. The inner wall of the primary gear shaft 1-6-1 is provided with an internal thread for connecting the screw assembly 3, which cooperates with the screw 3-1 to form a screw nut. The screw 1-8 moves linearly under the drive of the nut, and has the advantages of high transmission efficiency, high transmission accuracy, and high service life. The nut support cover 1-9 is mounted on the positioning nut 1-2 and the screw bearing 1-7.

[0034] like Figure 5 As shown, the screw assembly 3 includes a screw 3-1 and a connecting seat 3-2. The screw 3-1 is provided with an external thread for threading with the internal thread at the lower end of the first gear shaft 1-6-1. The lower end of the screw 3-1 is connected to the middle of the upper surface of the connecting seat 3-2 and is integrally formed. The connecting seat 3-2 is fixedly connected to the middle of the upper surface of the large disc 2-2 of the actuator by screws, so as to drive the four push rods 2-4 on one side to move simultaneously through the screw assembly 3.

[0035] like Figure 6 As shown, according to the stiffness of the disc spring 2-3 inside the actuator 2 and the different placement positions, they are respectively called flexible end actuators and rigid end actuators, and the flexible end actuators and rigid end actuators are respectively located on both sides of the test mass 4. The purpose of such a setting is that if rigid end actuators are used on both sides, an over-constrained structural system will be formed, and it will be difficult to achieve uniform force distribution. Therefore, the combination of flexible end actuators and rigid end actuators can solve the above contradictions, achieve high preload locking of the test mass, and avoid the problem of over-positioning.

[0036] like Figure 7As shown, the flexible end actuator comprises an adjustable end cap 2-1, a large disc 2-2, a disc spring 2-3, four push rods 2-4, and a strain gauge pressure sensor 2-5. The large disc 2-2 is provided with four mounting holes 2-2-1 for cooperating with the push rods 2-4. The lower end of each push rod 2-4 is inserted into a corresponding mounting hole 2-2-1. A limiting ring 2-4-1 is provided on the upper part of each push rod 2-4. The disc spring 2-3 is sleeved on the push rod 2-4 and is located between the upper surface of the limiting ring 2-4-1 and the lower surface of the adjustable end cap 2-1. The adjustable end cap 2-1 is threadedly connected to the upper end of the push rod 2-4. The adjustable end cap 2-1 presses the disc spring 2-3, thereby pressing the push rod 2-4 onto the large disc 2-2. In addition, the rigidity of the disc spring 2-3 inside the flexible end actuator is relatively small, which is conducive to adjusting and averaging the contact force of the four push rods 2-4 on the same side.

[0037] like Figure 8 As shown, the rigid end actuator includes an adjustable end cover 2-1, a large disc 2-2, a disc spring 2-3, four push rods 2-4 and a strain gauge pressure sensor 2-5. The large disc 2-2 is provided with four mounting holes 2-2-1 for cooperating with the push rod 2-4. The lower end of each push rod 2-4 is inserted into a corresponding mounting hole 2-2-1. A limit ring 2-4-1 is provided on the upper part of each push rod 2-4. The disc spring 2-3 is sleeved on the push rod 2-4 and is located between the lower surface of the limit ring 2-4-1 and the bottom plate of the mounting hole 2-2-1. The adjustable end cover 2-1 is threadedly connected to the upper end of the push rod 2-4. The adjustable end cover 2-1 presses the push rod 2-4, and then presses the disc spring 2-3 against the large disc 2-2. In addition, the rigidity of the disc spring 2-3 inside the rigid end actuator is relatively large, which is conducive to high-precision positioning after the test mass is locked.

[0038] Preferably, the rigid end disc spring 2-3 can be replaced by a spring.

[0039] Preferably, the inner wall of each mounting hole 2-2-1 is provided with a limiting groove for installing a limiting ring 2-4-1, and the outer edge of the limiting ring 2-4-1 is provided with a protrusion that matches the limiting groove, which can prevent the top rod 2-4 from rotating and play a limiting role.

[0040] Preferably, the lower end of each of the push rods 2-4 is provided with a hemispherical protrusion 2-4-2, and the hemispherical protrusion 2-4-2 is used to correspond to the ball socket of the test mass to facilitate positioning and force application.

[0041] Working principle:

[0042] 1. Connection process

[0043] First, install the four push rods 2-4 of the locking mechanism into the large disc 2-2, and tighten the two through the adjustable end cover 2-1 and the disc spring 2-3, and connect the screw 1-8 to the large disc 2-2. Then put it into the base 6, and the screw 3-1 of the screw assembly 3 extends from the base 6. After installing the gear nut and the screw bearing 1-7 in the secondary gear reducer 1-6, screw the screw 3-1, and install the nut support cover 1-9 on the base 6 by screws. Then install the positioning nut 1-2 and the screw bearing 1-7 into the nut support cover 1-9. Through the gear shaft bearing 1-4 and the elastic retaining ring 1-5, the gear shaft of the secondary gear reducer 1-6 is placed in the nut support cover 1-9. Finally, the output shaft of the ultrasonic motor 1-1 is connected to the primary pinion 1-6-2 of the secondary gear reducer 1-6 through the positioning nut 1-2 and the deep groove ball bearing 1-3 to complete the assembly of the whole machine.

[0044] 2. Working process:

[0045] Due to the large vibration during the launch process, the ejector rods 2-4 are required to provide a large locking force to lock the test mass without damaging the surface of the test mass. The accuracy of the work during the ground installation phase is particularly important. The specific working process is as follows:

[0046] During the ground installation and locking stage, to ensure that the locking force is evenly distributed on the eight push rods 2-4. First, start the ultrasonic motor 1-1 at the rigid end, rotate the screw 3-1 and drive the large disc 2-2 to move in the vertical direction until it touches the limit device of the base 6, at which time the ultrasonic motor 1-1 stops and locks. Place the test mass 4 on the four push rods 2-4 at the rigid end, and adjust the longitudinal length of the push rod 2-4 by adjusting the compression amount of the disc spring 2-3 through the adjustable end cover 2-1 to center the test mass. Then start the ultrasonic motor 1-1 at the flexible end, so that the push rod 2-4 touches the surface of the test mass 4. When the large disc 2-2 touches the limit device on the base 6, the ultrasonic motor 1-1 stops working and locks. The strain gauge pressure sensor 2-5 on the push rod 2-4 works, and the pressure is measured according to the strain gauge pressure sensor 2-5 on each push rod 2-4. By adjusting the adjustable end cover 2-1 to continuously adjust the compression amount of the disc spring 2-3, the pressure of each push rod 2-4 is finally uniform. Complete the test quality ground installation locking work.

[0047] During the on-track unlocking stage, the ultrasonic motor 1-1 at the flexible end rotates in the opposite direction, driving the push rod 2-4 of the flexible end actuator to slowly retreat until the strain gauge pressure sensors 2-5 on all push rods 2-4 indicate zero, to ensure that the unlocking process does not interfere with the test mass. After that, it enters the fast retreat state, and the ultrasonic motors 1-1 at both ends rotate rapidly, driving the actuators 2 at both ends to quickly move away from the test mass 4 and retreat to the predetermined position, so as to improve the efficiency of the unlocking process.

[0048] During the repeated locking process on the track, the ultrasonic motors 1-1 on both sides rotate slowly to drive the actuators 2 at both ends to move simultaneously, and the push rods 2-4 on both sides slowly approach the test mass. When the strain gauge pressure sensor 2-5 produces an indication, it means that the end of the push rod 2-4 is in contact with the test mass 4. At this time, the ultrasonic motor 1-1 at the flexible end continues to rotate, and the ultrasonic motor 1-1 at the rigid end stops. In this way, the locking force is slowly applied to the test mass 4 until the sensor indication reaches the required locking force, and the ultrasonic motor 1-1 at the flexible end stops working, indicating that the repeated locking is completed.

[0049] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. An eight-point locking device for repeatedly locking a test mass, wherein a locking device is symmetrically arranged on both sides of a test mass (4), each locking device comprising a transmission mechanism (1), an actuator (2) and a screw assembly (3), wherein the transmission mechanism (1) is connected to the actuator (2) via the screw assembly (3), the transmission mechanism (1) comprises an ultrasonic motor (1-1) and a gear reducer assembly, wherein the output shaft of the ultrasonic motor (1-1) is fixedly connected to the input end of the gear reducer assembly, and the output end of the gear reducer assembly is connected to the screw assembly (3); characterized in that: According to the different installation positions of the disc spring inside the actuator (2), the actuator (2) is divided into a flexible end actuator and a rigid end actuator, wherein the flexible end actuator and the rigid end actuator are respectively located on both sides of the test mass (4). The flexible end actuator comprises an adjustable end cover (2-1), a large disc (2-2), a disc spring (2-3), four push rods (2-4), and a strain gauge pressure sensor (2-5); the large disc (2-2) is respectively provided with four mounting holes (2-2-1) for cooperating with the push rods (2-4); the lower end of each push rod (2-4) is inserted into a corresponding mounting hole (2-2-1); a limiting ring (2-4-1) is provided at the upper part of each push rod (2-4); the disc spring (2-3) is sleeved on the push rod (2-4) and is located between the upper surface of the limiting ring (2-4-1) and the lower surface of the adjustable end cover (2-1); the adjustable end cover (2-1) is threadedly connected to the upper end of the push rod (2-4); and a strain gauge pressure sensor (2-5) is provided at the lower part of each push rod (2-4); The rigid end actuator comprises an adjustable end cover (2-1), a large disc (2-2), a disc spring (2-3), four push rods (2-4) and a strain gauge pressure sensor (2-5). The large disc (2-2) is respectively provided with four mounting holes (2-2-1) for cooperating with the push rods (2-4). The lower end of each push rod (2-4) is inserted into a corresponding mounting hole (2-2-1). A limiting ring (2-4-1) is provided at the upper part of each push rod (2-4). The disc spring (2-3) is sleeved on the push rod (2-4) and is located between the lower surface of the limiting ring (2-4-1) and the bottom plate of the mounting hole (2-2-1). The adjustable end cover (2-1) is threadedly connected to the upper end of the push rod (2-4). The lower part of each push rod (2-4) is provided with a strain gauge pressure sensor (2-5).

2. An eight-point locking device for repeated locking of test mass according to claim 1, characterized in that: The inner wall of each mounting hole (2-2-1) is provided with a limiting groove for mounting a limiting ring (2-4-1), and the outer edge of the limiting ring (2-4-1) is provided with a protrusion matching the limiting groove.

3. An eight-point locking device for repeated locking of test mass according to claim 1, characterized in that: A hemispherical protrusion (2-4-2) is provided at the lower end of each push rod (2-4).

4. A locking method for an eight-point locking device for repeated locking of test quality according to claim 1, characterized in that: The method comprises the following steps: Step 1: During the ground installation and locking stage, first start the ultrasonic motor (1-1) at the rigid end, so that the screw rod (3-1) rotates and drives the large disc (2-2) to move in the vertical direction until it touches the limit device of the base (6). At this time, the ultrasonic motor (1-1) stops and locks; place the test mass (4) on the four push rods (2-4) at the rigid end, and adjust the compression amount of the disc spring (2-3) by adjusting the adjustable end cover (2-1) to adjust the longitudinal length of the push rod (2-4) so ​​that the test mass is centered; then the ultrasonic motor (1-1) at the flexible end Start, so that the push rod (2-4) touches the surface of the test mass (4); when the large disc (2-2) touches the limit device on the base (6), the ultrasonic motor (1-1) stops working and is locked; the strain gauge pressure sensor (2-5) on the push rod (2-4) works, and the pressure is measured by the strain gauge pressure sensor (2-5) on each push rod (2-4); the compression amount of the disc spring (2-3) is continuously adjusted by adjusting the adjustable end cover (2-1) to finally make the pressure of each push rod (2-4) uniform; complete the ground installation and locking work of the test mass; Step 2: During the on-track unlocking phase, the ultrasonic motor (1-1) at the flexible end rotates in the opposite direction, driving the push rod (2-4) of the flexible end actuator to slowly retreat until the readings of the strain gauge pressure sensors (2-5) on all the push rods (2-4) are zero, so as to ensure that the unlocking process does not interfere with the test mass; thereafter, the system enters a rapid retreat state, and the ultrasonic motors (1-1) at both ends rotate rapidly, driving the actuators (2) at both ends to quickly move away from the test mass (4) and retreat to a predetermined position, so as to improve the efficiency of the unlocking process; Step 3: During the repeated locking process on the track, the ultrasonic motors (1-1) on both sides rotate slowly to drive the actuators (2) at both ends to move simultaneously, and the push rods (2-4) on both sides slowly approach the test mass. When the strain gauge pressure sensor (2-5) produces an indication, it indicates that the end of the push rod (2-4) is in contact with the test mass (4). At this time, the ultrasonic motor (1-1) at the flexible end continues to rotate, and the ultrasonic motor (1-1) at the rigid end stops, thereby slowly applying a locking force to the test mass (4) until the sensor indication reaches the required locking force, and the ultrasonic motor (1-1) at the flexible end stops working, indicating that the repeated locking is completed.

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