A conductive hairspring bending moment measurement system using aerostatic bearings

Abstract

The present invention discloses a conductive hairspring bending moment measurement system using a gas hydrostatic bearing. The measurement system includes a spindle motor, a coupling, a rotary table, a rotary shaft, a platform, a workbench, and a grating system, wherein: the rotary table is cold-mounted on the rotary shaft; the rotary shaft is connected to the spindle motor via a coupling; the platform is fixed to the workbench and symmetrically arranged on both sides of the rotary table; the grating system includes a circular scale grating, a reading head, and a grating digital display; the circular scale grating is wound around the outer surface of the rotary table; the reading head is fixed to the workbench and used in conjunction with the circular scale grating; the grating digital display is integrated with an electronic subdivision circuit and is connected to the reading head via a cable. The present invention can test the combined torque of conductive hairsprings of different structures and materials to determine the hairspring arrangement scheme with the minimum interference torque, and realize measurement automation through control.

Description

Technical Field

[0001] The present invention belongs to the technical field of inertial navigation, and relates to a conductive hairspring bending moment measurement system, and in particular to a conductive hairspring bending moment measurement system using a gas hydrostatic bearing. Background Art

[0002] Inertial technology is a technique that enables continuous sensing of the trajectory and attitude of a controlled object, independent of external interference. Inertial instruments such as gyroscopes and accelerometers are important measurement sensors in inertial systems. They offer advantages such as high precision and a wide range. They are used to measure the attitude, position, and angular velocity of a missile relative to an inertial space reference. Based on this data, the missile is precisely controlled to ensure it hits its target or remains on track. The gyroscope's motor rotates at high speed, supported by an air bearing. The fixed axis of the high-speed rotating rigid body is used to establish an inertial reference, and its precession is used to measure angular velocity. A sensor measures angular motion and outputs the position signal as an electrical signal. The pendulum assembly in the accelerometer is centered by the air bearing. When the sensitive axis is subjected to acceleration, the pendulum assembly's position changes. This change signal is input to an amplifier, which drives a torque generator to generate feedback torque that balances the inertial torque acting on the proof mass, causing it to reset. The accelerometer output is an electrical signal proportional to the input acceleration, flowing through the torque generator. The motor gyro and pendulum assembly are supported by air bearings and mounted within a float filled with inert gas. The float assembly, including the float, sensor rotor, and torquer rotor, is assembled within the housing and completely suspended in the oil. The electrical signal required by the float is input via a conductive hairspring, one end of which is welded to the float and the other to the terminal in the housing. The conductive hairspring is the primary signal transmission component, serving as the intermediary between the moving and fixed parts. Therefore, its performance and accuracy directly impact the accuracy of the inertial navigation system.

[0003] Due to the complex shape and small size of conductive hairsprings, analyzing and calculating the stiffness of hairsprings with different structures and materials, as well as the resulting interference torque after assembly, is extremely difficult. Existing analysis methods often use the finite element method (FEM), an approximate solution. Insufficient mesh density or a finite element model that fails to accurately reflect the actual operating environment can result in varying degrees of error.

[0004] Assembly stress in a conductive hairspring is a significant source of error in high-precision micro-inertial instrument components. The difference between the free-standing and assembled forms of a conductive hairspring generates elastic stress, which in turn creates a reaction torque in the inertial environment, introducing errors in signal transmission. The interference torque introduced by the conductive hairspring itself is unavoidable and non-negligible. Generally, a conductive hairspring must meet conductivity requirements while maintaining low stiffness to ensure free rotation of the float around its axis. Optimizing the hairspring design can mitigate the impact of bias error. For example, hairspring materials with good conductivity and a low elastic modulus can be selected; while meeting signal transmission requirements and ensuring process feasibility, the hairspring's working length can be increased and its cross-sectional thickness reduced. Furthermore, the cross-sectional shape and mounting angle of the conductive hairspring can also contribute to differences in stiffness. Therefore, it is desirable to design a measurement device that can easily and accurately determine the hairspring layout that achieves good conductivity, low stiffness, and minimizes interference torque. Summary of the Invention

[0005] The purpose of the present invention is to provide a conductive hairspring bending moment measurement system using a gas hydrostatic bearing with good stability, high precision and convenient measurement. The measurement system utilizes the advantages of the air bearing's frictionlessness and high precision to more accurately measure the interference torque caused by the conductive hairspring assembly stress of a small magnitude. The combined torque of conductive hairsprings with different structures and materials can be tested to determine the hairspring arrangement scheme with the minimum interference torque, and measurement automation is achieved through control.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A conductive hairspring bending moment measurement system using a gas static pressure bearing includes a spindle motor, a coupling, a rotary table, a rotary shaft, a platform, a workbench, and a grating system, wherein:

[0008] The spindle motor uses a gas static pressure bearing and is controlled by a servo drive;

[0009] The rotary table cold-loading sleeve is arranged on the rotary shaft;

[0010] The rotary shaft is connected to the spindle motor via a coupling;

[0011] The platform is fixed on the workbench and is symmetrically arranged on both sides of the rotary workbench;

[0012] The grating system includes a circular scale grating, a reading head and a grating digital display;

[0013] The circular scale grating is wound around the outer surface of the rotary table;

[0014] The reading head is fixed on the workbench and used in pair with the circular scale grating;

[0015] The grating digital display is integrated with an electronic subdivision circuit and is connected to a reading head via a cable.

[0016] A method for measuring the bending moment of a conductive hairspring using the above-mentioned measurement system comprises the following steps:

[0017] Step 1: Weld a pair of conductive hairsprings symmetrically in the same horizontal plane, with one side of the conductive hairspring welded to the upper surface of the platform and the other side welded to the upper surface of the rotary table;

[0018] Step 2: The spindle motor is controlled by an external servo driver. The servo driver issues a servo start command, and the spindle motor and the rotary table are locked.

[0019] Step 3: Turn off the servo drive. Under the action of the reaction torque generated by the stress of the conductive hairspring assembly, the rotary table rotates, and the circular scale grating and the reading head produce relative displacement;

[0020] Step 4: The photoelectric sensitive element in the reading head converts the light and dark changing Moiré fringes into electrical signal output. The electrical signal is input into the electronic subdivision circuit through a cable for high-multiple subdivision. The angular displacement and time of the rotary table's rotation can be obtained and displayed on the grating digital display. The angular acceleration of the rotary table's rotation is calculated from the read data. The torque obtained by further calculation is the interference torque generated by the stress of the conductive hairspring assembly.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The present invention utilizes the characteristics of gas hydrostatic bearings, such as stable operation, large bearing capacity, frictionless and high precision, to more accurately measure the interference torque generated by the conductive hairspring. Pressurized gas enters the gap through the throttle, and a pressure gas film is generated in the gap to make the electric spindle rotor float. Under ideal conditions, the spindle rotor can achieve stable and frictionless rotation. The spindle motor and the rotary table connected to it are locked by the control of the servo driver. After the conductive hairspring to be measured is welded on the workbench, the servo driver is turned off. The interference torque generated by the assembly stress of the conductive hairspring causes the rotary table to rotate, and the circular scale grating and the reading head produce relative displacement. The photoelectric sensitive element in the reading head converts the light and dark changing Moiré fringes into electrical signal output. The electrical signal is input into the electronic subdivision circuit through a cable for high-multiple subdivision to achieve arc-second reading.

[0023] 2. The present invention can measure the interference torque generated by conductive hairsprings of different materials, cross-sectional shapes, sizes and installation angles, so as to determine the arrangement of the conductive hairspring with the minimum interference torque and realize measurement automation through control. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1Schematic diagram of the axial cross-section structure of the high-precision gas static pressure rotary device of the present invention;

[0025] Figure 2 Schematic diagram of the hardware of the conductive hairspring interference torque measurement system of the present invention;

[0026] Figure 3 Schematic diagram of the three-dimensional structure of the conductive hairspring interference torque measurement system of the present invention;

[0027] In the figure, 1. motor, 11. motor seat, 12. motor end cover, 13. motor shaft, 14. motor rotor, 15. motor stator, 2. rear end cover, 3. gas static pressure rear bearing, 31. rear bearing seat, 32. rear porous radial bearing, 33. rear porous thrust bearing, 34. rear inlet flow duct, 4. gas static pressure front bearing, 41. front bearing seat, 42. front porous thrust bearing, 43. front porous radial bearing, 44. outlet flow duct, 45. forward flow duct, 5. front end cover, 6. electric spindle, 7. coupling, 8. rotary table, 9. rotary axis, 10. circular scale grating, 16. platform, 17. workbench, 18. reading head, 19. cable, 20. conductive hairspring. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below with reference to the accompanying drawings, but the present invention is not limited thereto. Any modification or equivalent substitution of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention shall be included in the scope of protection of the present invention. In the description of the present invention, it should be understood that the terms "upper," "lower," "horizontal," "longitudinal," and other directional terms are merely for the purpose of facilitating the description of the present invention and do not indicate or imply that the elements referred to must have a specific orientation. Furthermore, the use of a porous throttling method in the gas hydrostatic bearing in the description of the invention is for the purpose of facilitating the description of the present invention and therefore should not be construed as a specific limitation of the present invention.

[0029] In the present invention, the shell is a cylindrical surface, the generatrix direction of the cylindrical surface is called the axial direction, and the radius direction on the same circular cross section is called the radial direction.

[0030] like Figure 1-Figure 3 As shown, the conductive hairspring bending moment measurement system using a gas static pressure bearing provided by the present invention includes a spindle motor, a coupling 7, a rotary table 8, a rotary shaft 9, a platform 16, a workbench 17 and a grating system, wherein:

[0031] The spindle motor includes a motor 1, a rear end cover 2, a gas static pressure rear bearing 3, a gas static pressure front bearing 4, a front end cover 5, and an electric spindle 6. The motor 1 is cold-mounted on the electric spindle 6, and the rear end cover 2, the gas static pressure rear bearing 3, the gas static pressure front bearing 4, and the front end cover 5 are coaxially sleeved on the electric spindle 6 and connected by bolts.

[0032] The rotary table 8 is cold-mounted on the rotary shaft 9;

[0033] The rotary shaft 9 is connected to the motor shaft 6 via a coupling 7;

[0034] The platform 16 is fixed on the workbench 17;

[0035] The platform 16 is a pair of columns symmetrically fixedly arranged on both sides of the rotary table 8, and the upper surface of the platform 16 and the upper surface of the rotary table 8 are in the same horizontal plane;

[0036] The grating system includes a circular scale grating 10, a reading head 18, a cable 19 and a grating digital display. The circular scale grating 10 is wound around the outer wall of the rotary worktable 8. The reading head 18 is fixed on the worktable 17 and used in pair with the circular scale grating 10. The grating digital display is integrated with an electronic subdivision circuit and is connected to the reading head 18 via a cable 19.

[0037] In the present invention, the electric spindle 6 is a "Z"-shaped cylindrical structure with an annular flange provided in the middle.

[0038] In the present invention, the motor 1 includes a motor shaft 13, a motor rotor 14, a motor stator 15, a motor base 11 and a motor end cover 12, wherein: the motor shaft 13 is cold-mounted on the electric spindle 6, the motor rotor 14 is cold-mounted on the motor shaft 13, the motor stator is cold-mounted in the motor base 11, the motor base 11 is coaxially mounted on the electric spindle 6, and the upper surface of the motor base 11 contacts the lower surface of the rear end cover 2 and is connected by bolts, and the upper surface of the motor end cover 12 contacts the lower surface of the motor base 11 and is connected by bolts.

[0039] In the present invention, the gas static pressure rear bearing 3 takes a porous throttling gas static pressure bearing as an example, including a rear bearing seat 31, a rear porous radial bearing 32, a rear porous thrust bearing 33, and a rear intake air duct 34, wherein: the upper surface of the rear bearing seat 31 is provided with an annular groove A, the lower surface of the annular groove A is provided with an intake air duct A, one side of the intake air duct A is connected to the annular groove A through a rectangular chamfer 342, and the other side of the intake air duct A is connected to the rear intake air duct 34; the rear bearing seat An annular groove A is radially opened on the inner wall of 31, and an intake flow channel B is opened on the inner wall of the annular groove A. One side of the intake flow channel B is connected with the annular groove A through a rectangular chamfer 341, and the other side of the intake flow channel B is connected with the rear intake flow channel 34; the rear porous radial bearing 32 is a cylindrical structure, arranged in the annular groove A on the inner wall of the rear bearing seat 31 and sleeved on the electric spindle 6; the rear porous thrust bearing 33 is a circular ring structure, arranged in the circular ring groove A on the upper surface of the rear bearing seat 31.

[0040] In the present invention, the gas static pressure front bearing 4 takes a porous throttling gas static pressure bearing as an example, including a front bearing seat 41, a front porous radial bearing 43, a front porous thrust bearing 42, an inlet air flow channel 45 and an outlet air flow channel 44. The lower surface of the front bearing seat 41 is provided with an annular groove, and the annular flange of the electric spindle 6 is located in the annular groove. The upper surface of the annular groove is provided with a circular annular groove B, and the upper surface of the circular annular groove B is provided with an inlet air flow channel C. One side of the inlet air flow channel C is connected to the circular annular groove B through a rectangular chamfer 451. The inlet air flow channel C is connected to the circular annular groove B through a rectangular chamfer 451. The other side is connected to the forward air flow duct 45; an annular groove B is radially opened on the inner wall of the front bearing seat 41, and an intake air flow duct D is opened on the inner wall of the annular groove B. One side of the intake air flow duct D is connected to the annular groove B through a rectangular chamfer 452, and the other side of the intake air flow duct D is connected to the forward air flow duct 45; the front porous radial bearing 43 is a cylindrical structure, which is arranged in the annular groove B on the inner wall of the front bearing seat 41 and is sleeved on the electric spindle 6; the front porous thrust bearing 42 is a circular ring structure, which is arranged in the circular ring groove B on the lower surface of the front bearing seat 41.

[0041] In the present invention, an annular hole is provided between the inner wall of the gas static pressure rear bearing 3 and the outer wall of the cylindrical structure below the annular flange of the electric spindle 6, and an annular hole is provided between the upper surface of the gas static pressure rear bearing 3 and the lower surface of the annular flange of the electric spindle 6.

[0042] In the present invention, an annular hole is provided between the inner wall of the annular groove of the gas static pressure front bearing 4 and the outer wall of the annular flange of the electric spindle 6, an annular hole is provided between the inner wall of the gas static pressure front bearing 4 and the outer wall of the cylindrical structure above the annular flange of the electric spindle 6, and an annular hole is provided between the upper surface of the annular groove of the gas static pressure front bearing 4 and the upper surface of the annular flange of the electric spindle 6.

[0043] In the present invention, the annular apertures provided between the gas static pressure front bearing 4 and the electric spindle 6, and the annular apertures provided between the gas static pressure rear bearing 3 and the electric spindle 6, are interconnected.

[0044] The above-mentioned measurement system can be used to measure the interference torque generated by the assembly stress of a pair of symmetrical conductive hairsprings 20. The specific measurement method is as follows:

[0045] Step 1: Weld a pair of conductive hairsprings 20 symmetrically in the same horizontal plane, with one side of the conductive hairspring 20 welded to the upper surface of the platform 16 and the other side welded to the upper surface of the rotary table 8.

[0046] Step 2: The spindle motor is controlled by an external servo driver. The servo driver issues a servo start command, and the spindle motor and the rotary table 8 are locked.

[0047] Step 3: Turn off the servo driver. Under the action of the reaction torque generated by the assembly stress of the conductive hairspring 20, the rotary table 8 rotates, and the circular scale grating 10 and the reading head 18 produce relative displacement.

[0048] Step 4: The photoelectric sensitive element in the reading head 18 converts the light and dark changing Moiré fringes into electrical signal output. The electrical signal is input into the electronic subdivision circuit through the cable 19 for high-multiple subdivision. The angular displacement and time of the rotation of the rotary table 8 can be obtained and displayed on the grating digital display. The angular acceleration of the rotation of the rotary table is calculated from the read data. The torque further calculated according to the law of fixed-axis rotation of a rigid body is the interference torque generated by the stress of the conductive hairspring assembly.

Claims

1. A conductive hairspring bending moment measurement system using a gas hydrostatic bearing, characterized in that The measuring system includes a spindle motor, a coupling, a rotary table, a rotary axis, a platform, a workbench and a grating system, wherein: The spindle motor uses a gas static pressure bearing and is controlled by a servo drive; The rotary table cold-loading sleeve is arranged on the rotary shaft; The rotary shaft is connected to the spindle motor via a coupling; The platform is fixed on the workbench and is symmetrically arranged on both sides of the rotary workbench; The grating system includes a circular scale grating, a reading head and a grating digital display; The circular scale grating is wound around the outer surface of the rotary table; The reading head is fixed on the workbench and used in pair with the circular scale grating; The grating digital display is integrated with an electronic subdivision circuit and is connected to a reading head via a cable.

2. The conductive hairspring bending moment measurement system using a gas static pressure bearing according to claim 1, characterized in that The spindle motor includes a motor, a rear end cover, a gas static pressure rear bearing, a gas static pressure front bearing, a front end cover, and an electric spindle, wherein: the motor is cold-mounted on the electric spindle, and the rear end cover, the gas static pressure rear bearing, the gas static pressure front bearing and the front end cover are coaxially sleeved on the electric spindle.

3. The conductive hairspring bending moment measurement system using a gas static pressure bearing according to claim 2, characterized in that The electric spindle is a "Z"-shaped cylindrical structure with an annular flange in the middle.

4. The conductive hairspring bending moment measurement system using a gas static pressure bearing according to claim 2, characterized in that The motor includes a motor shaft, a motor rotor, a motor stator, a motor base and a motor end cover, wherein: the motor shaft is cold-mounted on the electric spindle, the motor rotor is cold-mounted on the motor shaft, the motor stator is cold-mounted in the motor base, the motor base is coaxially mounted on the electric spindle, and the upper surface of the motor base is connected to the lower surface of the rear end cover, and the upper surface of the motor end cover is connected to the lower surface of the motor base.

5. The conductive hairspring bending moment measurement system using a gas static pressure bearing according to claim 2, characterized in that The annular apertures provided between the gas static pressure front bearing and the electric spindle, and the annular apertures provided between the gas static pressure rear bearing and the electric spindle, are interconnected.

6. The conductive hairspring bending moment measurement system using a gas static pressure bearing according to claim 2 or 5, characterized in that The gas static pressure rear bearing is a porous throttling gas static pressure bearing, including a rear bearing seat, a rear porous radial bearing, a rear porous thrust bearing, and a rear intake air flow channel, wherein: a circular annular groove A is provided on the upper surface of the rear bearing seat, an intake air flow channel A is provided on the lower surface of the circular annular groove A, one side of the intake air flow channel A is connected to the circular annular groove A through a rectangular chamfer, and the other side of the intake air flow channel A is connected to the rear intake air flow channel; an annular groove A is radially provided on the inner wall of the rear bearing seat, an intake air flow channel B is provided on the inner wall of the annular groove A, one side of the intake air flow channel B is connected to the annular groove A through a rectangular chamfer 341, and the other side of the intake air flow channel B is connected to the rear intake air flow channel; the rear porous radial bearing is arranged in the annular groove A on the inner wall of the rear bearing seat and is sleeved on the electric spindle; the rear porous thrust bearing is arranged in the circular annular groove A on the upper surface of the rear bearing seat.

7. The conductive hairspring bending moment measurement system using a gas static pressure bearing according to claim 6, characterized in that An annular aperture is provided between the inner side wall of the gas static pressure rear bearing and the outer side wall of the cylindrical structure below the annular flange of the electric spindle, and an annular aperture is provided between the upper surface of the gas static pressure rear bearing and the lower surface of the annular flange of the electric spindle.

8. The conductive hairspring bending moment measurement system using a gas static pressure bearing according to claim 2 or 5, characterized in that The gas static pressure front bearing is a porous throttling gas static pressure bearing, including a front bearing seat, a front porous radial bearing, a front porous thrust bearing, a forward air flow channel and an outgoing air flow channel, the lower surface of the front bearing seat is provided with an annular groove, the annular flange of the electric spindle is located in the annular groove, the upper surface of the annular groove is provided with a circular annular groove B, the upper surface of the circular annular groove B is provided with an inlet air flow channel C, one side of the inlet air flow channel C is connected to the circular annular groove B through a rectangular chamfer, and the other side of the inlet air flow channel C is connected to the forward air flow channel; the inner wall of the front bearing seat is radially provided with an annular groove B, the inner wall of the annular groove B is provided with an inlet air flow channel D, one side of the inlet air flow channel D is connected to the annular groove B through a rectangular chamfer, and the other side of the inlet air flow channel D is connected to the forward air flow channel; the front porous radial bearing is arranged in the annular groove B on the inner wall of the front bearing seat and is sleeved on the electric spindle; the front porous thrust bearing is arranged in the annular groove B on the lower surface of the front bearing seat.

9. The conductive hairspring bending moment measurement system using a gas static pressure bearing according to claim 8, characterized in that An annular hole is provided between the inner wall of the annular groove of the gas static pressure front bearing and the outer wall of the annular flange of the electric spindle, an annular hole is provided between the inner wall of the gas static pressure front bearing and the outer wall of the cylindrical structure above the annular flange of the electric spindle, and an annular hole is provided between the upper surface of the annular groove of the gas static pressure front bearing and the upper surface of the annular flange of the electric spindle.

10. A method for measuring the bending moment of a conductive hairspring using the measurement system according to any one of claims 1 to 9, characterized in that The method comprises the following steps: Step 1: Weld a pair of conductive hairsprings symmetrically in the same horizontal plane, with one side of the conductive hairspring welded to the upper surface of the platform and the other side welded to the upper surface of the rotary table; Step 2: The spindle motor is controlled by an external servo driver. The servo driver issues a servo start command, and the spindle motor and the rotary table are locked. Step 3: Turn off the servo drive. Under the action of the reaction torque generated by the stress of the conductive hairspring assembly, the rotary table rotates, and the circular scale grating and the reading head produce relative displacement; Step 4: The photoelectric sensitive element in the reading head converts the light and dark changing Moiré fringes into electrical signal output. The electrical signal is input into the electronic subdivision circuit through a cable for high-multiple subdivision. The angular displacement and time of the rotary table's rotation can be obtained and displayed on the grating digital display. The angular acceleration of the rotary table's rotation is calculated from the read data. The torque obtained by further calculation is the interference torque generated by the stress of the conductive hairspring assembly.

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