Multi-circle angular displacement measuring device based on single gear structure

Abstract

A multi-circle angular displacement measuring device based on a single gear structure comprises a shell, a rotating shaft, a driving wheel, a driven wheel, magnetic steel, a deep groove ball bearing, a circuit board and a Hall chip. Three deep groove ball bearings are respectively mounted in holes in the upper and lower end faces of the bottom of the shell; the small-section end of the rotating shaft penetrates through the first deep groove ball bearing and the second deep groove ball bearing, and the root of the rotating shaft is inserted into a mounting hole of the driving wheel. The driving wheel is fixed with the inner ring of the deep groove ball bearing II; the first magnetic steel is installed in a groove of the driving wheel. A driven wheel is fixed with an inner ring of the deep groove ball bearing III, and teeth of the driven wheel are meshed with teeth of the driving wheel; the second magnetic steel is installed in a groove of the driven wheel. The circuit board is arranged on a boss in the shell; the first Hall chip and the second Hall chip are installed on the circuit board and axially correspond to the first magnetic steel and the second magnetic steel respectively. The device is high in vibration resistance, small in accumulative error, high in positioning precision, absolute in mechanical measurement, capable of achieving real absolute multi-circle angle measurement and capable of being used for application needing to track multiple rotation periods.

Description

Technical Field

[0001] This invention belongs to the field of aerospace angular displacement measurement, specifically relating to a multi-turn angular displacement measuring device based on a single gear structure. Background Technology

[0002] Multi-turn angular displacement measuring devices are widely used in industrial, precision instrument, robotics, and aerospace servo fields. Multi-turn absolute angular displacement measuring devices are particularly important in scenarios that require long-term reliable measurement of rotation angles because they can directly obtain absolute position information without initial calibration or cumulative counting, such as servo motor control and spacecraft attitude adjustment control.

[0003] Traditional multi-turn absolute angular displacement measuring devices often employ a composite structure of "gear sets + multiple sensors": multiple sets of gears with different transmission ratios are used to detect single-turn angular displacement and the number of turns, and then the data is fused to obtain the multi-turn absolute position. This type of structure has obvious limitations: the meshing of multiple gear sets requires sufficient space, resulting in a large overall size of the device; the high installation accuracy requirements of the gear sets increase the complexity and cost of the manufacturing process; mechanical wear and clearance errors occur during gear meshing, and measurement accuracy decreases over long-term use.

[0004] The patent [A Mechanical Multi-Turn Absolute Encoder, CN202020073707.6, authorized] uses four driven gears with mutually prime tooth counts and one driving gear to achieve multi-turn absolute measurement. Its advantage is true mechanical multi-turn measurement, but its disadvantages include a large number of gears, a large volume, poor shock resistance, and decreased accuracy over long-term use. The patent [Accumulating Error-Free Gear Encoder, CN202111668772.9, authorized] uses a base gear and a combination of meshing differential gears. Based on the differential principle, it reduces the number of gears. Its advantage is a simple single-stage reduction structure, but its disadvantages include still using a five-gear combination, large installation space, high manufacturing difficulty, and high cost. Furthermore, it uses a four-group differential combination principle, resulting in a large data processing computation and high MCU requirements. Summary of the Invention

[0005] Overcoming the shortcomings of existing technologies, this invention proposes a multi-turn angular displacement measuring device based on a single gear structure, which features strong vibration resistance, small cumulative error, high-precision positioning, and absolute mechanical measurement, achieving true absolute multi-turn angle measurement and can be used in applications that require tracking multiple rotation cycles.

[0006] A multi-turn angular displacement measuring device based on a single gear structure includes a housing, an end cover, a rotating shaft, a driving wheel, a driven wheel, a magnet one, a magnet two, a deep groove ball bearing one, a deep groove ball bearing two, a deep groove ball bearing three, a circuit board, a Hall chip one, and a Hall chip two. Three deep groove ball bearings are fixedly installed in holes on the upper and lower end faces of the bottom of the housing. The small-section end of the rotating shaft passes through deep groove ball bearing one and deep groove ball bearing two, and the root of the rotating shaft is inserted into the mounting hole of the driving wheel and fixed with screws. The driving wheel is fixed to the inner ring of deep groove ball bearing two. Magnet one is fixedly installed in the groove of the driving wheel. The driven wheel is fixed to the inner ring of deep groove ball bearing three, ensuring that the teeth of the driven wheel and the driving wheel mesh. Magnet two is fixedly installed in the groove of the driven wheel. The circuit board is mounted and fixed on a boss inside the housing. Hall chips one and two are mounted on the circuit board, corresponding axially to magnets one and two, respectively. The end cover is fixed to the top of the housing.

[0007] The number of teeth on the driving gear and the driven gear follows the relationship between Z and Z+1, and there is no common factor. When the driving gear rotates Z+1 full revolutions, the driven gear rotates Z full revolutions. The actual rotation angles of the driving and driven gears are exactly 360° apart.

[0008] Furthermore, the angle difference between the driving wheel and the driven wheel per revolution is Δδ = 360° × 1 / (Z+1); when the driving wheel 4 rotates N revolutions, the cumulative angle difference between the driving wheel and the driven wheel is Δδ' = N × Δδ.

[0009] Furthermore, by determining the range of the δ2-δ1 value, the number of rotations of the measuring device can be determined; δ2 and δ1 represent the angle values ​​of the driving wheel 4 and driven wheel 5 collected by the circuit board 8, respectively. If Δδ×N<δ2-δ1<Δδ×(N+1), then the measuring device has rotated N times.

[0010] Furthermore, the rotation direction of the angular displacement measuring device is determined based on the change in the cumulative angle difference Δδ' between the driving and driven wheels. If the driving wheel rotates in the positive direction, the value of Δδ' increases; if the driving wheel rotates in the negative direction, the value of Δδ' decreases.

[0011] The circuit board collects angles ranging from 0 to 360°, which are the angle values ​​of a single rotation of the driving wheel and the driven wheel, respectively.

[0012] The Hall chip one and Hall chip two are located 0.5 to 2 mm above the axial direction of the driving wheel and driven wheel, respectively.

[0013] The Hall chip one and Hall chip two respectively realize independent single-turn angular displacement measurement. They adopt AMR anisotropic magnetoresistive technology to realize 0 to 360° absolute angular position measurement, 21-bit core angular resolution, and a maximum speed of 120,000 rpm, achieving a nonlinear error of <±0.07° throughout the entire stroke range.

[0014] Technical invention points:

[0015] (1) The present invention uses a transmission structure in which a single gear meshes with the driving gear on the main shaft. The number of teeth of the driving and driven gears follows the relationship between Z and Z+1, and there is no common factor. When the driving gear rotates Z+1 full turns, the driven gear rotates Z full turns. The actual rotation angles of the driving and driven gears are exactly 360° apart, thus realizing true absolute measurement.

[0016] (2) The single-turn angle difference between the driving and driven gears in this invention is Δδ = 360° × 1 / (Z+1). When the driving gear rotates N times, the cumulative angle difference Δδ' = N × Δδ. The data difference between the driving and driven gears is fixed and does not repeat within Z+1 turns. The number of rotations of the device is measured by determining the range of the angle difference between the driving and driven gears.

[0017] (3) The present invention utilizes the position information of the drive gear on the main shaft to realize the angular position measurement within the range of 0 to 360°.

[0018] (4) The obtained circle number information and the angle position information within the range of 0 to 360° are integrated into a multi-circle angle position measurement information.

[0019] (5) The maximum count (number of revolutions) achieved by the present invention is M = 360° / △δ.

[0020] (6) The information of the driving gear and the information of the driven gear in this invention are independent angular position information within the range of 0 to 360°, and are redundant to each other.

[0021] (7) The present invention has magnets installed on the driving gear and the driven gear, and Hall position detection sensor chips are axially corresponding to the magnets.

[0022] The beneficial effects of this invention are as follows:

[0023] (1) The angular displacement measuring device of the present invention is a structure design that uses only a single gear meshing, compared with the traditional method of using five gear sets, which reduces the cumulative error, improves the measurement accuracy and vibration resistance, and reduces the spatial volume of the measuring device.

[0024] (2) The tooth count design of the driving and driven gears of the angular displacement measuring device of the present invention follows the relationship between Z and Z+1, and there is no common factor. The data difference between the driving gear and the driven gear is fixed and non-repeating within Z+1 turns, realizing true absolute multi-turn measurement. While obtaining the number of turns information, the absolute position information of the measuring device can also be obtained.

[0025] (3) The angular displacement measuring device of the present invention adopts gear mechanical connection, which can realize absolute measurement of the revolution after power failure, thus breaking through and solving the problem of information blind spot after power failure of previous electronic counting.

[0026] (4) The present invention can identify the rotation direction of the angular displacement measuring device based on the change in the angle difference between the driving and driven wheels, such as whether it increases or decreases.

[0027] (5) The driving gear and driven gear of the present invention independently acquire angular position information within the range of 0 to 360°, which has redundant functions. At the same time, based on the acquired number of revolutions and the angular position information within the range of 0 to 360°, they are fused into a multi-revolution angular position measurement information. Compared with the traditional multi-gear group information fusion technology, the MCU calculation is smaller and faster, which improves the dynamic response speed of the measuring device. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a multi-turn angular displacement measuring device based on a single gear structure.

[0029] Figure 2 This is a schematic diagram of the master-slave gear connection structure;

[0030] Among them, 1-housing, 2-end cover, 3-shaft, 4-drive wheel, 5-driven wheel, 6-1-magnet one, 6-2-magnet two, 7-1-deep groove ball bearing one, 7-2-deep groove ball bearing two, 7-3-deep groove ball bearing three, 8-circuit board, 9-1-Hall chip one, 9-2-Hall chip two Detailed Implementation

[0031] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection claimed by the present invention.

[0032] like Figure 1 , 2 As shown, a multi-turn angular displacement measuring device based on a single gear structure includes a housing 1, an end cover 2, a rotating shaft 3, a driving wheel 4, a driven wheel 5, magnets 6-1 / 6-2, deep groove ball bearings 7-1 / 7-2 / 7-3, a circuit board 8, and Hall effect chips 9-1 / 9-2.

[0033] Three deep groove ball bearings 7-1, 7-2, and 7-3 are fixedly installed in the holes on the upper and lower end faces of the bottom of the housing 1, respectively. The small-section end of the rotating shaft 3 passes through the deep groove ball bearings 7-1 and 7-2, and the root of the rotating shaft 3 is inserted into the mounting hole of the drive wheel 4 and fixed with screws. The drive wheel 4 is fixed to the inner ring of the bearing 7-2. The magnet 6-1 is fixedly installed in the groove of the drive wheel 4. The driven wheel 5 is fixed to the inner ring of the bearing 7-3 to ensure that the teeth of the driven wheel 5 and the drive wheel 4 mesh with each other. The magnet 6-2 is fixedly installed in the groove of the driven wheel 5. The circuit board 8 is mounted and fixed on the boss inside the housing 1. Hall chips 9-1 and 9-2 are mounted on the circuit board 8 and are axially corresponding to the magnets 6-1 and 6-2, respectively. The end cap 2 is fixed to the top of the housing 1.

[0034] The aforementioned angular displacement measuring device is designed with only a single gear meshing structure. This is to reduce the cumulative error generated in gear transmission and improve measurement accuracy, and to reduce mechanical connection points, thereby improving reliability and vibration resistance.

[0035] The circuit board 8 collects angles ranging from 0 to 360°, which are the angle values ​​of a single rotation of the driving wheel 4 and the driven wheel 5. There are Hall effect sensor chips on the circuit board at an axial height of 0.5 to 2 mm above the driving wheel 4 and the driven wheel 5, which are used to detect position angle information within the range of 0 to 360°.

[0036] The number of teeth on the driving wheel 4 and the driven wheel 5 follows a relationship of Z and Z+1, such that the angle difference between the driving and driven wheels per revolution is Δδ = 360° × 1 / (Z+1). For every revolution of the driving wheel 4, the driven wheel 5 lags behind by Δδ. When the driving wheel 4 rotates Z+1 revolutions, the driven wheel 5 lags behind by a full 360°, i.e., it rotates Z revolutions, constituting a complete measurement cycle, thus achieving true absolute measurement.

[0037] When the driving wheel 4 rotates N times, the cumulative angular difference Δδ' between the driving and driven wheels is Δδ = N × Δδ. If δ2 and δ1 represent the angle values ​​of the driving wheel 4 and driven wheel 5 collected by the circuit board 8, respectively, then the number of rotations of the measuring device can be determined by judging the range of the δ2-δ1 value. If Δδ × N < δ2 - δ1 < Δδ × (N + 1), then the measuring device has rotated N times.

[0038] This invention provides a detailed explanation using the example of driving gear 4 and driven gear 5 having 63 and 64 teeth, respectively. The angular relationship and number of rotations between driving gear 4 and driven gear 5 are shown in Table 1. The data difference between the driving gear and driven gear is fixed and non-repeating within 64 rotations, where Δδ = 360° × 1 / (Z+1), Z = 63, Z+1 = 64, therefore Δδ = 360° × 1 / 64 = 5.625°.

[0039] Table 1. Angular relationship between driving wheel 4 and driven wheel 5 and determination of number of rotations.

[0040]

[0041]

[0042] If 5.625×1<δ2-δ1<5.625×2, then it has rotated more than one revolution, and so on.

[0043] The angular displacement measuring device can determine the actual rotation angle, δ2+N×360, based on the number of revolutions and the angle value collected by circuit board 8. It can acquire both the number of revolutions and the actual rotation angle, breaking the limitation of traditional measuring devices that can only acquire the rotation angle information of the last revolution.

[0044] The angular displacement measuring device adopts a battery-free gear meshing structure design. Based on the inertial rotation of the gear, the absolute measurement of the number of revolutions after power failure can be obtained.

[0045] The cumulative angular difference Δδ' of the driving and driven wheels in the angular displacement measuring device is N × Δδ. If the driving wheel rotates in the positive direction, the value of Δδ' increases; if the driving wheel rotates in the negative direction, the value of Δδ' decreases. The rotation direction of the angular displacement measuring device can be determined based on the change in the cumulative angular difference Δδ' between the driving and driven wheels.

[0046] In the aforementioned angular displacement measuring device, position sensing Hall chips 9-1 and 9-2 respectively realize independent single-turn angular displacement measurement. Using AMR anisotropic magnetoresistive technology, it can achieve absolute angular position measurement from 0 to 360°, with a core angular resolution of 21 bits, a maximum rotation speed of 120,000 rpm, and a nonlinear error of <±0.07° throughout the entire stroke range.

[0047] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-turn angular displacement measuring device based on a single gear structure, characterized in that, The device includes a housing, end caps, a shaft, a drive wheel, a driven wheel, magnet one, magnet two, deep groove ball bearing one, deep groove ball bearing two, deep groove ball bearing three, a circuit board, Hall effect chip one, and Hall effect chip two. Three deep groove ball bearings are fixedly installed in holes on the upper and lower end faces of the housing bottom. The small-section end of the shaft passes through deep groove ball bearing one and deep groove ball bearing two, and the root of the shaft is inserted into the mounting hole of the drive wheel and fixed with screws. The drive wheel is fixed to the inner ring of deep groove ball bearing two. Magnet one is fixedly installed in the groove of the drive wheel. The driven wheel is fixed to the inner ring of deep groove ball bearing three, ensuring that the teeth of the driven wheel and the drive wheel mesh. Magnet two is fixedly installed in the groove of the driven wheel. The circuit board is mounted and fixed on a boss inside the housing. Hall effect chips one and two are mounted on the circuit board, corresponding axially to magnet one and magnet two, respectively. The end cap is fixed to the top of the housing.

2. The multi-turn angular displacement measuring device based on a single gear structure according to claim 1, characterized in that, The number of teeth on the driving gear and the driven gear follows the relationship between Z and Z+1, and there is no common factor. When the driving gear rotates Z+1 full revolutions, the driven gear rotates Z full revolutions. The actual rotation angles of the driving and driven gears are exactly 360° apart.

3. The multi-turn angular displacement measuring device based on a single gear structure according to claim 2, characterized in that, The angle difference between the driving wheel and the driven wheel per revolution is Δδ = 360° × 1 / (Z+1); when the driving wheel 4 rotates N revolutions, the cumulative angle difference between the driving wheel and the driven wheel is Δδ' = N × Δδ.

4. The multi-turn angular displacement measuring device based on a single gear structure according to claim 3, characterized in that, By determining the range of the δ2-δ1 value, the number of rotations of the measuring device can be determined; δ2 and δ1 represent the angle values ​​of the driving wheel 4 and driven wheel 5 collected by the circuit board 8, respectively. If Δδ×N<δ2-δ1<Δδ×(N+1), then the measuring device has rotated N times.

5. The multi-turn angular displacement measuring device based on a single gear structure according to claim 4, characterized in that, The rotation direction of the angular displacement measuring device is determined by the change in the cumulative angle difference Δδ' between the driving and driven wheels. If the driving wheel rotates in the positive direction, the value of Δδ' increases; if the driving wheel rotates in the negative direction, the value of Δδ' decreases.

6. The multi-turn angular displacement measuring device based on a single gear structure according to claim 1, characterized in that, The circuit board collects angles ranging from 0 to 360°, which are the angle values ​​of a single rotation of the driving wheel and the driven wheel, respectively.

7. The multi-turn angular displacement measuring device based on a single gear structure according to claim 1, characterized in that, The Hall chip one and Hall chip two are located 0.5 to 2 mm above the axial direction of the driving wheel and driven wheel, respectively.

8. The multi-turn angular displacement measuring device based on a single gear structure according to claim 1, characterized in that, The Hall chip one and Hall chip two respectively realize independent single-turn angular displacement measurement. They adopt AMR anisotropic magnetoresistive technology to realize 0 to 360° absolute angular position measurement, 21-bit core angular resolution, and a maximum speed of 120,000 rpm, achieving a nonlinear error of <±0.07° throughout the entire stroke range.

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