Inertial moment measuring device

Abstract

The application discloses an inertia moment measuring device, wherein a magnetic suspension bearing on the device comprises a rotor and a stator; a rotating part to be measured is coaxially fixed with the rotor; a pay-off wheel is coaxially fixed with the rotor, and one end of a pull wire is wound on the pay-off wheel; a pull wire driving assembly comprises a constant speed motor, a take-up wheel and a circular limiting wheel; the constant speed motor drives the take-up wheel to rotate at a constant speed, and the other end of the pull wire is wound on the outer periphery of the take-up wheel; the part of the pull wire between the take-up wheel and the pay-off wheel forms a straightening section, the straightening section is perpendicular to the rotating axis of the rotating part to be measured, and is tangent to the pull wire at a cutting point; the take-up wheel is slidingly arranged, the circular limiting wheel is fixed in position, the positions where the circular limiting wheel and the take-up wheel are tangent are located on the same side of the take-up wheel, and the outer periphery profile of the take-up wheel is a involute, so that the distance change from the cutting point of the pull wire to the rotating axis of the take-up wheel is proportional to the rotating angle of the take-up wheel; and a tension sensor measures the tension of the pull wire. The application makes the measurement of the inertia moment more convenient and accurate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of physical quantity measuring instrument, in particular to an inertia moment measuring device. BACKGROUND

[0002] For a part rotating around an axis, its inertia moment (also called rotational inertia) determines its rotation performance, so the measurement of inertia moment is very important.

[0003] For a rigid body with regular shape and uniform mass distribution, its inertia moment around a specific rotation axis can be calculated by mathematical method, but for a rigid body with complex shape or non-uniform mass distribution, it is very difficult to calculate its inertia moment by mathematical method, so experimental method is usually used to measure it.

[0004] In experiments, the inertia moment of a rigid body is generally measured by making the rigid body move in a certain form, and then the inertia moment of the rigid body is indirectly measured by describing the relationship between a specific physical quantity of the motion and the inertia moment. Common experimental methods include three-wire pendulum, etc.

[0005] However, in the existing experimental methods, there are many values to be measured, and the experimenter needs to record each value to be measured, and then calculate the inertia moment of the object according to the corresponding kinematic formula, which is time-consuming and laborious, and the measurement accuracy is difficult to guarantee. SUMMARY

[0006] The purpose of the present application is to provide an inertia moment measuring device to overcome the above-mentioned defects, and make the measurement process of inertia moment more simple and accurate.

[0007] To achieve the above purpose, the solution of the present application is: an inertia moment measuring device, comprising a magnetic suspension bearing, a pay-off wheel, a wire driving assembly, a wire and a tension sensor;

[0008] The magnetic suspension bearing comprises a rotor and a stator, and the rotor is suspended under the magnetic force of the stator; the measured rotating part is coaxially fixed with the rotor to make the measured rotating part freely rotate around its own rotation axis;

[0009] The pay-off wheel is coaxially fixed with the rotor to rotate with the measured rotating part, and one end of the wire is wound on the pay-off wheel;

[0010] The pull wire driving assembly comprises a constant speed motor, a take-up wheel and a circular limiting wheel, the constant speed motor is connected to and drives the take-up wheel to rotate at a constant speed, and the other end of the pull wire is wound around the outer periphery of the take-up wheel; the part of the pull wire between the take-up wheel and the pay-off wheel forms a straightening section, the straightening section is perpendicular to the rotation axis of the to-be-tested rotating member and is tangent to the pull wire at a pull wire tangent point; the take-up wheel is slidingly arranged, the circular limiting wheel is fixed in position, the positions where the circular limiting wheel and the take-up wheel are tangent are located on the same side of the take-up wheel as the positions where the straightening section and the take-up wheel are tangent, and the outer periphery contour of the take-up wheel is a involute, so that the distance from the pull wire tangent point to the rotation axis of the take-up wheel changes in direct proportion to the rotation angle of the take-up wheel;

[0011] A tension sensor is mounted on the pull wire for measuring the tension of the pull wire.

[0012] Further, the magnetic suspension bearing is provided with two, the two magnetic suspension bearings are symmetrically arranged, and the to-be-tested rotating member is fixed between rotors of the two magnetic suspension bearings.

[0013] Further, the stator comprises two first electromagnets arranged side by side, the two first electromagnets are fixed in position, the rotor is a cylindrical permanent magnet and is located above and between the two first electromagnets, and the two first electromagnets are used to apply magnetic force in the radial direction of the rotor to suspend the rotor.

[0014] Further, the stator further comprises a second electromagnet located on one axial side of the rotor, the second electromagnet is fixed in position and spaced from the rotor, and is used to apply magnetic force in the axial direction of the rotor.

[0015] Further, the magnetic suspension bearing further comprises a displacement sensor group and a controller, the displacement sensor group is used to collect spatial position information of the rotor, and the displacement sensor group, the second electromagnet and the two first electromagnets are all communicatively connected to the controller, so that the second electromagnet and the two first electromagnets adjust the magnetic force according to the spatial position information of the rotor.

[0016] Further, the displacement sensor group comprises a fixedly arranged photoelectric position sensor, a first Hall sensor and a second Hall sensor, the photoelectric position sensor is located directly above the rotor, the first Hall sensor is located below the rotor, and the second Hall sensor is located on one axial side of the rotor.

[0017] Further, a base frame and a portal frame are further included, the magnetic suspension bearing is fixed on the base frame, the portal frame is fixed above the base frame, and the pull wire driving assembly is arranged on the portal frame.

[0018] Further, a horizontal sliding track is formed on the door frame, the pull wire driving assembly has a sliding frame, the sliding frame is slidingly installed on the sliding track, the constant speed motor and the take-up reel are installed on the sliding frame, and the circular limiting wheel is installed on the door frame.

[0019] Further, a horizontal sliding track is formed on the door frame, the sliding frame is provided with a rolling wheel, the rolling wheel rolls in the sliding track, and the sliding frame slides along the sliding track.

[0020] With the above scheme, the application has the following beneficial effects: the magnetic suspension bearing is used to suspend the to-be-tested rotating member and make it freely rotate around the rotation axis, the take-up reel and the to-be-tested rotating member rotate together, one end of the pull wire is wound on the take-up reel, the other end of the pull wire is wound on the outer periphery of the take-up reel, the take-up reel is driven by the constant speed motor to rotate at a constant speed, the pull wire is wound into the take-up reel, the part of the pull wire between the take-up reel and the take-up reel is tensioned to form a straight section, the tangent point of the straight section and the take-up reel is on the same side of the take-up reel, the movement of the tangent point of the pull wire is limited, the outer periphery of the take-up reel is in the shape of an involute, the distance from the tangent point of the pull wire to the rotation axis of the take-up reel is proportional to the rotation angle of the take-up reel, the pull wire is uniformly accelerated and recovered by the constant speed motor, the to-be-tested rotating member and the take-up reel are uniformly accelerated and rotated together, the angular acceleration of the to-be-tested rotating member is a known quantity, the tension of the pull wire is measured by the tension sensor, the driving moment of the to-be-tested rotating member is obtained, and the inertia moment of the to-be-tested rotating member is calculated. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the application.

[0022] Figure 2 It is a schematic diagram of the three-dimensional structure of the application. Figure 1 It is a partial enlarged view of A in the middle.

[0023] Figure 3 It is a schematic diagram of the three-dimensional structure of the application.

[0024] Figure 4 It is a schematic diagram of the three-dimensional structure of the application.

[0025] Figure 5 It is a schematic diagram of the three-dimensional structure of the application.

[0026] Figure 6 It is a schematic diagram of the three-dimensional structure of the application.

[0027] Figure 7 Fig. 6 is a schematic view of the take-up reel rotating to another angle when winding the pull wire.

[0028] Label explanation: 1-magnetic suspension bearing, 2-winding wheel, 4-pull wire, 5-tension sensor, 6-rotor, 7-stator, 8-rotating part to be measured, 9-constant speed motor, 10-take-up reel, 11-circular limit wheel, 12-straight section, 13-pull wire cut point, 14-first electromagnet, 15-second electromagnet, 16-displacement sensor group, 18-optoelectronic position sensor, 19-first Hall sensor, 20-second Hall sensor, 21-chassis, 22-gantry, 23-slide, 24-sliding frame, 25-roller. DETAILED DESCRIPTION

[0029] The application will be described in detail below in combination with the drawings and specific embodiments.

[0030] The application provides a kind of inertial moment measuring device, as shown in Figures 1-7 Including magnetic suspension bearing 1, winding wheel 2, pull wire driving assembly, pull wire 4 and tension sensor 5;

[0031] Magnetic suspension bearing 1 includes rotor 6 and stator 7, rotor 6 is suspended under the magnetic force of stator 7, the magnetic suspension bearing 1 can be any kind of existing magnetic suspension bearing that can be fed back by sensor, ensure that when load is applied, rotor 6 position will not move with load;Rotating part to be measured 8 is coaxially fixed with rotor 6, so that rotating part to be measured 8 rotates freely around its own rotation axis, to avoid rotating part to be measured 8 in the process of rotation produces the frictional resistance that hinders rotating part to be measured 8 rotation;

[0032] Winding wheel 2 is coaxially fixed with rotor 6, to rotate with rotating part to be measured 8, one end of pull wire 4 is wound on winding wheel 2, the pull wire 4 is thin wire with diameter being negligible;

[0033] The cable drive assembly includes a constant-speed motor 9, a take-up reel 10, and a circular limit wheel 11. The constant-speed motor 9 can be any existing servo motor or stepper motor capable of controlling the rotation speed. In this embodiment, a stepper motor is preferred. The constant-speed motor 9 is connected to and drives the take-up reel 10 to rotate at a constant speed. The other end of the cable 4 is wound around the outer circumference of the take-up reel 10. The constant-speed motor 9 drives the take-up reel 10 to rotate at a constant speed to wind up and retract the cable 4, so that the portion of the cable 4 located between the take-up reel 10 and the release reel 2 is tensioned to form a straightened section 12. The straightened section 12 is perpendicular to the rotation axis of the rotating component 8 to be tested and is tangent to the take-up reel 10 at the cable tangency point 13. Preferably, the take-up reel 10 is located directly above the release reel 2, and the rotation axis of the take-up reel 10 is perpendicular to the rotating component 8 to be tested. The rotation axis of the moving part 8 is perpendicular; the take-up reel 10 is linearly slidable, the circular limit wheel 11 is fixed in position and tangent to the take-up reel 10, the position where the circular limit wheel 11 and the take-up reel 10 are tangent is on the same side of the take-up reel 10 as the position where the straightening section 12 and the take-up reel 10 are tangent. When the distance from the pull point 13 to the rotation axis of the take-up reel 10 increases, the circular limit wheel 11 will push against the take-up reel 10, causing the take-up reel 10 to move, thereby keeping the pull point 13 within a small range of movement, so that the movement of the pull point 13 can be ignored in subsequent calculations. The outer periphery of the take-up reel 10 is an involute, so that the change in the distance from the pull point 13 to the rotation axis of the take-up reel 10 is proportional to the rotation angle of the take-up reel 10.

[0034] Assuming the line connecting the point of tangency 13 of the pull line to the axis of rotation of the take-up reel 10 is perpendicular to the pull line 4, when it is not perpendicular, calculations can be performed based on velocity decomposition, and the displacement of the point of tangency of the pull line is negligible. Therefore, kinematic calculations yield:

[0035] r1 = r0 + bt;

[0036] v1=ω1r1=ω1(r0+bt)=ω1r0+ω1bt;

[0037] α = v'1(t) = ω1b;

[0038] Where r1 is the actual distance from the wire pulling point 13 to the rotation axis of the take-up reel 10 during the working process, r0 is the distance from the wire pulling point 13 to the rotation axis of the take-up reel 10 in the initial state, b is the proportional coefficient between the change in distance from the wire pulling point 13 to the rotation axis of the take-up reel 10 and the rotation angle of the take-up reel 10, t is the rotation time of the constant speed motor 9, v1 is the wire recovery speed, ω1 is the angular velocity of the take-up reel 10, and α is the acceleration of the wire.

[0039] Since ω1 and b are both constants, the acceleration of the pull line is a constant value, and the angular acceleration of the pay-off wheel 2 is a constant value, which is equal to the angular acceleration of the measured rotating member 8. According to the formula: M = Jα1, M is the moment, J is the moment of inertia, and α1 is the angular acceleration of the measured rotating member 8, J = M / α1 can be obtained. At this time, only one variable M needs to be measured to obtain J. Since the magnetic suspension bearing 1 allows the measured rotating member 8 to rotate freely around its own rotation axis, air resistance is ignored, and M is equal to the tension of the pull line 4.

[0040] The tension sensor 5 is installed on the pull line 4 to measure the tension of the pull line 4, and then the moment of inertia J can be obtained. The measurement process is very simple and accurate.

[0041] In the preferred embodiment, in order to make the rotation process of the measured rotating member 8 more stable and facilitate the balance of the force moment caused by the pull line 4 pulling the pay-off wheel 2 to overturn the measured rotating member 8, the magnetic suspension bearing 1 is provided with two magnetic suspension bearings 1, the two magnetic suspension bearings 1 are symmetrically arranged, and the measured rotating member 8 is fixed between the rotors 6 of the two magnetic suspension bearings 1.

[0042] More specifically, the magnetic suspension bearing 1 has the following structure. The stator 7 includes two first electromagnets 14 arranged side by side. The two first electromagnets 14 are fixed in position. The rotor 6 is a cylindrical permanent magnet and is located above and between the two first electromagnets 14. The two first electromagnets 14 are used to apply magnetic force in the radial direction of the rotor 6 to suspend the rotor 6. The stator 7 also includes a second electromagnet 15 located on one axial side of the rotor 6. The second electromagnet 15 is fixed in position and spaced from the rotor 6 to apply magnetic force in the axial direction of the rotor 6. The magnetic suspension bearing 1 also includes a displacement sensor group 16 and a controller, which is not shown in the figure. The controller can be any existing device such as a personal computer that can accept processing and output signals. The displacement sensor group 16 is used to collect spatial position information of the rotor 6. Specifically, the displacement sensor group 16 includes a fixed photoelectric position sensor 18, a first Hall sensor 19, and a second Hall sensor 20. The photoelectric position sensor 18 is located directly above the rotor 6. The first Hall sensor 19 is located below the rotor 6. The second Hall sensor 20 is located on one axial side of the rotor 6. The displacement sensor group 16, the second electromagnet 15, and the two first electromagnets 14 are all communicatively connected to the controller, so that the second electromagnet 15 and the two first electromagnets 14 can adjust the magnetic force according to the spatial position information of the rotor 6 to prevent displacement of the measured rotating member 8.

[0043] More specifically, in the embodiment, the magnetic suspension bearing 1 is fixed on a base frame 21, a portal frame 22 is fixed above the base frame 21, the wire drive assembly is arranged on the portal frame 22, a horizontally extending slide 23 is formed on the portal frame 22, the wire drive assembly has a sliding frame 24, a roller 25 is arranged on the sliding frame 24, the roller 25 rolls in the slide 23, the sliding frame 24 is slidingly installed on the slide 23 and slides along the slide 23, the constant speed motor 9 and the take-up reel 10 are installed on the sliding frame 24, and the circular limiting wheel 11 is installed on the portal frame 22.

[0044] The above merely describes the preferred embodiment of the present application, and is not intended to limit the design of the present application. Any equivalent changes made according to the key design of the present application shall fall within the protection scope of the present application.

Claims

1. An inertial torque measuring device, characterized in that: It includes a magnetic levitation bearing (1), a wire feeding wheel (2), a wire pulling drive assembly, a wire (4), and a tension sensor (5); The magnetic levitation bearing (1) includes a rotor (6) and a stator (7). The rotor (6) is suspended under the magnetic force of the stator (7). The rotating part (8) to be tested is fixed coaxially with the rotor (6) so that the rotating part (8) to be tested can rotate freely around its own rotation axis. The wire feeding wheel (2) is fixed coaxially with the rotor (6) so that it rotates together with the rotating part (8) to be tested. One end of the wire (4) is wound around the wire feeding wheel (2). The wire pulling drive assembly includes a constant speed motor (9), a take-up reel (10), and a circular limit wheel (11). The constant speed motor (9) is connected to and drives the take-up reel (10) to rotate at a constant speed. The other end of the wire (4) is wound around the outer circumference of the take-up reel (10). The part of the wire (4) located between the take-up reel (10) and the release reel (2) forms a straightening section (12). The straightening section (12) is perpendicular to the rotation axis of the rotating part (8) to be measured and is tangent to the take-up reel (10) at the wire tangency point (1). 3) The take-up reel (10) is slidably set, the circular limit wheel (11) is fixed in position and tangent to the take-up reel (10). The position where the circular limit wheel (11) and the take-up reel (10) are tangent is on the same side of the take-up reel (10) as the position where the straightening section (12) and the take-up reel (10) are tangent. The outer circumferential contour of the take-up reel (10) is an involute, so that the change in distance from the tangent point (13) of the pull line to the rotation axis of the take-up reel (10) is proportional to the rotation angle of the take-up reel (10). The tension sensor (5) is installed on the tension wire (4) to measure the tension of the tension wire (4).

2. The inertial torque measuring device as described in claim 1, characterized in that: There are two magnetic levitation bearings (1), which are symmetrically arranged. The rotating part (8) to be tested is fixed between the rotors (6) of the two magnetic levitation bearings (1).

3. The inertial torque measuring device as described in claim 1, characterized in that: The stator (7) includes two first electromagnets (14) arranged side by side, the two first electromagnets (14) are fixed in position, the rotor (6) is a cylindrical permanent magnet and is located above the position between the two first electromagnets (14), the two first electromagnets (14) are used to apply magnetic force to the rotor (6) in the radial direction so that the rotor (6) is levitated.

4. The inertial torque measuring device as described in claim 3, characterized in that: The stator (7) also includes a second electromagnet (15) located on one side of the axial direction of the rotor (6). The second electromagnet (15) is fixed in position and spaced apart from the rotor (6) for applying magnetic force in the axial direction of the rotor (6).

5. The inertial torque measuring device as described in claim 4, characterized in that: The magnetic levitation bearing (1) also includes a displacement sensor group (16) and a controller. The displacement sensor group (16) is used to collect the spatial position information of the rotor (6). The displacement sensor group (16), the second electromagnet (15) and the two first electromagnets (14) are all communicatively connected to the controller so that the second electromagnet (15) and the two first electromagnets (14) can adjust the magnetic force according to the spatial position information of the rotor (6).

6. The inertial torque measuring device as described in claim 5, characterized in that: The displacement sensor group (16) includes a fixedly installed photoelectric position sensor (18), a first Hall sensor (19) and a second Hall sensor (20). The photoelectric position sensor (18) is located directly above the rotor (6), the first Hall sensor (19) is located below the rotor (6), and the second Hall sensor (20) is located on one side of the axial direction of the rotor (6).

7. The inertial torque measuring device as described in claim 1, characterized in that: It also includes a base frame (21) and a gantry (22), the magnetic levitation bearing (1) is fixed on the base frame (21), the gantry (22) is fixed above the base frame (21), and the pull-wire drive assembly is disposed on the gantry (22).

8. The inertial torque measuring device as described in claim 7, characterized in that: A horizontally extending slide rail (23) is formed on the gantry (22). The cable drive assembly has a sliding frame (24) which is slidably mounted on the slide rail (23). The constant speed motor (9) and the take-up reel (10) are mounted on the sliding frame (24). The circular limit wheel (11) is mounted on the gantry (22).

9. The inertial torque measuring device as described in claim 8, characterized in that: The sliding frame (24) is provided with rollers (25), which roll in the slide rail (23) so that the sliding frame (24) slides along the slide rail (23).

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