Micro-Newton meter-scale torque sensor based on photoelectric principle

Abstract

A micro-Newton meter-scale torque sensor based on a photoelectric principle belongs to the technical field of torque measurement and comprises a shell used for accommodating a shading sleeve, a static grating, a movable grating, a light intensity detection plate and a light source. The two ends of the deformation shaft are installed on the shell respectively; a plurality of elastic columns arranged in the axial direction are machined in the middle of the deformation shaft in the circumferential direction, and a gap is formed between every two adjacent elastic columns. A light intensity detection plate, a movable grating, a static grating and a light source are sequentially arranged from the stress end to the fixed end of the deformation shaft; the static grating and the movable grating are arranged at intervals in the axial direction and installed on the deformation shaft, light and dark stripes of the static grating and the movable grating are arranged in a staggered mode, and the light intensity detection plate and the light source are installed on the shading sleeve. And the shading sleeve is positioned by the shell. The device can be widely applied to the aspects of bearing friction torque measurement, elastic element torsion characteristic test and the like when being used for measuring the micro-Newton meter-scale torque.

Description

Technical Field

[0001] The present invention relates to a measuring device, in particular to a micro-newton-meter torque sensor based on a photoelectric principle, belonging to the technical field of torque measurement. Background Art

[0002] The friction torque of a bearing is the combined torque opposing the direction of rotation, generated by the relative motion between the inner ring, outer ring, cage, and rolling elements during bearing operation. Friction torque is a critical performance indicator for rolling bearings, directly related to energy loss, temperature, noise, and vibration changes during bearing rotation. Bearings play a vital role in high-precision instruments. However, traditional bearing friction torque measurement and elastic element torsional characteristic testing devices struggle to accurately measure small torques, particularly those in the micron-meter range. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies by providing a micron-meter torque sensor based on photoelectric principles. This sensor has a large deformation capacity and can measure small moments. Its structural deformation minimizes material deformation, resulting in a wide linear range and capable of measuring micron-meter torques.

[0004] A micro-newton-meter torque sensor based on photoelectric principle, comprising: The housing is used to accommodate the light shielding sleeve, the static grating, the dynamic grating, the light intensity detection plate and the light source; A deformable shaft, with both ends of the deformable shaft respectively mounted on the housing; A light intensity detection plate, a dynamic grating, a static grating and a light source are sequentially arranged from the force-bearing end to the fixed end along the deformation axis; The static grating and the dynamic grating are arranged along the axial gap and mounted on the deformation shaft. The light and dark stripes of the static grating and the dynamic grating are arranged alternately. The light intensity detection plate and the light source are respectively installed on the light shielding sleeve; The light shielding sleeve is positioned by the housing.

[0005] Furthermore, a cone is processed on the end of the deformation shaft adjacent to the light source, a threaded hole is processed on the top of the cone, and the cone is installed on the housing.

[0006] Furthermore, the deformable shaft comprises a deformable shaft force section, a deformable block and a deformable shaft fixed section; one end of the deformable block is connected to the deformable shaft force section, and the other end of the deformable block is connected to the deformable shaft fixed section.

[0007] Furthermore, the torque sensor also includes a limiter, which includes a positioning block and an L-shaped support. The positioning block is installed at the force-bearing end of the deformable shaft, and the L-shaped support is installed at the shell. A bolt is screwed on the L-shaped support, and the distance between the end of the bolt and the positioning block is adjustable.

[0008] Compared with the prior art, the present invention has the following advantages: This application uses a deformable shaft and photoelectric principles to achieve the measurement of tiny torques, which cannot be achieved with traditional strain gauges.

[0009] The torque sensor of this application can achieve 10 -6 The instrument measures torque in the Nm (1μNm) range with an accuracy exceeding 0.3%. The central column structure of the deformable shaft utilizes structural deformation to minimize material deformation. Under minimal torque, it achieves large deformation, a wide linear range, and a dynamic response exceeding 1500Hz. It is applicable to bearing friction torque measurement and testing the torsional characteristics of elastic components.

[0010] The following is a further description of the scheme of the application in conjunction with the accompanying drawings and embodiments: BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of the three-dimensional structure of a micro-newton-meter torque sensor based on the photoelectric principle of an embodiment; Figure 2 This is the main cross-sectional schematic diagram of this application; Figure 3 is a three-dimensional diagram of the deformed shaft of Example 1; Figure 4 is a main cross-sectional view of the deformed shaft of Example 1; Figure 5 For the Figure 4 CC cross-section in; Figure 6 This is a front view of the deformed shaft of Example 2; Figure 7 for Figure 6 A top view of Figure 8 For the Figure 7 dd cross-section in; Figure 9 This is a front view of the deformed shaft of Example 3; Figure 10 is a three-dimensional diagram of the deformation block of Example 3; Figure 11 is a schematic diagram of a light shield; Figure 12 is a schematic diagram of the positioning block; Figure 13 is a schematic diagram of an L-shaped support; Figure 14 is a schematic diagram of a static grating or a dynamic grating; Figure 15 This is the principle diagram of the torque sensor used in this application for measuring micron-meter-level torque.

[0012] In the figure: 1. back cover, 2. outer shell, 3. light-shielding sleeve, 4. static grating sleeve, 5. static grating, 6. dynamic grating, 7. pin I, 8. light intensity detection plate, 9. front cover, 10. deformation shaft, 11. limiter, 11-1. positioning block, 11-2. L-shaped support, 12. retaining ring, 13. oil-free bearing, 14. dynamic grating sleeve, 15. sealing ring I, 16. pin II, 17. pin III, 18. bearing, 19. pin IV, 20. light source, 21. sealing ring II, 22. shell, 100. elastic column, 101. cone, 102. threaded hole, 103. deformation shaft load section, 104. deformation block, 105. deformation shaft fixed section, 1041. coupling, 1042. flexible hinge, 1043. hollow column. DETAILED DESCRIPTION

[0013] The embodiments of the technical solution of the present invention will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the technical terms or scientific terms used in this application have the common meanings understood by those skilled in the art.

[0014] Example 1, reference Figure 1-Figure 5 The present embodiment provides a micro-newton-meter torque sensor based on a photoelectric principle, comprising: The housing 22 is used to accommodate the light shielding sleeve 3, the static grating 5, the dynamic grating 6, the light intensity detection plate 8 and the light source 20; A deformable shaft 10, with both ends of the deformable shaft 10 respectively mounted on the housing 22; The deformable shaft 10 is circumferentially processed with multiple elastic columns 100 or thin sheets arranged along the axial direction, with a gap between two adjacent elastic columns 100; a light intensity detection plate 8, a dynamic grating 6, a static grating 5 and a light source 20 are sequentially arranged along the deformable shaft 10 from the force-bearing end to the fixed end; The static grating 5 and the dynamic grating 6 are arranged along the axial gap and mounted on the deformation shaft 10; The light and dark stripes of the static grating 5 and the dynamic grating 6 are arranged alternately; The light intensity detection plate 8 and the light source 20 are respectively installed on the light shielding sleeve 3; The light shielding sleeve 3 is positioned by the housing 22 .

[0015] The design of the deformation axis 10 of this implementation scheme adopts distributed arrangement of columns, preferably four elastic columns, which form a hollow structure in a circumferential direction. The advantage is that the deformation is large and small torque can be measured. The structural deformation reduces the deformation of the material itself and has a large linear range.

[0016] Example 2, reference Figure 6-Figure 8The difference between this embodiment and embodiment 1 is that: two elastic columns 100 or thin sheets arranged along the axial direction are processed around the circumference of the deformation shaft 10, and the two elastic columns 100 are symmetrically arranged with a gap between them. The advantage of this structure is that the deformation is large, which can meet the measurement of small torques, and the linear range of structural deformation is large; along the deformation shaft 10 from the force-bearing end to the fixed end, a light intensity detection plate 8, a dynamic grating 6, a static grating 5 and a light source 20 are arranged in sequence.

[0017] In the above-mentioned embodiments 1 and 2, the end portion (defined as the fixed end) of the deformable shaft 10 adjacent to the light source 20 is processed with a cone 101 , the top of the cone 101 is processed with a threaded hole 102 , and the cone 101 is mounted on the housing 22 .

[0018] The taper of the cone 101 is 5:1-20:1. It is installed on the rear cover 1 through the cone surface fit and bolt tightening. The force-bearing end of the deformable shaft 10 is installed on the front cover 9 through the oil-free bearing I13. The oil-free bearing I13 is fixed by the retaining ring 12. Example 3: As an alternative to the deformable shaft 10, please refer to Figure 9 The deformable shaft 10 comprises a deformable shaft force section 103, a deformable block 104 and a deformable shaft fixed section 105; one end of the deformable block 104 is connected to the deformable shaft force section 103, and the other end of the deformable block 104 is connected to the deformable shaft fixed section 105. Figure 10 The deformable block 104 includes a coupling 1041, a flexible hinge 1042, and a hollow column 1043. The coupling 1041 is connected to the hollow column 1043 via the flexible hinge 1042. One end of the coupling 1041 extends into the hollow column 1043, connecting the two via the flexible hinge 1042. The end surface of the hollow column 413 has alternately arranged protrusions and grooves. The end surface of the deformable shaft force-bearing section 103 also has protrusions and grooves. The deformable shaft force-bearing section 103 and the hollow column 1043 are connected by the protrusions and grooves. The other end of the coupling 1041 is connected to the deformable shaft fixed section 105. For example, the hollow column 1043 is connected to the coupling 1041 by the protrusions and grooves and fixed with epoxy glue. The other end of the coupling 1041 is connected to the deformable shaft fixed section 105 by a set screw or epoxy glue.

[0019] In this embodiment, the coupling 1041 is connected to the hollow column 1043 through the flexible hinge 1042, and the overall structure is stable and reliable, so that the three-section connected deformation shaft 10 has a large deformation and can measure small torques. The structural deformation also reduces the deformation of the material itself and has a large linear range.

[0020] In this embodiment, the fixing method of the protruding claws and the grooves is adopted so that the three-section connected deformable shaft 10 can run continuously for a long time and has a good vibration reduction effect.

[0021] A silicon diode or silicon photocell is mounted on the light intensity detection board 8 to detect changes in light intensity. The light source 20 is an LED to provide light. The light intensity detection board 8 is mounted on the light shielding sleeve 3 via a pin I7. The light source 20 is mounted on the light shielding sleeve 3 via a pin IV19.

[0022] Reference Figure 15 The flexible structure of the column of the deformable shaft 10 is deformed when subjected to torque, causing the crossing angle between the dynamic grating 6 and the static grating 5 to change, causing the change in the light intensity received by the silicon diode or silicon photocell on the light intensity detection board 8, and further causing the change in the voltage across the silicon diode or silicon photocell, thereby measuring the torque applied to the deformable shaft 10.

[0023] Reference Figure 14 According to the design range of the torque sensor, when a certain micro torque is applied in the positive and negative directions, the rotation angle of the deformed shaft 10 is ± The light and dark stripes of the static grating 5 and the dynamic grating 6 should be staggered at an angle θ 2 matches, the matching relationship is , is the coefficient, =0.5-0.8. A silicon photocell or silicon diode is mounted on the medium light intensity detection board 8. Considering the linear range of light transmission of the silicon photocell and assembly accuracy requirements, the first-order mode of the deformation axis is greater than 1500 Hz.

[0024] Optionally, the number of light and dark stripes on the dynamic grating 6 and the number of dark and light stripes on the static grating 5 are the same, ranging from 72 to 360, with an initial staggered angle of 2.5° to 0.2°. Preferably, the light and dark stripes overlap to such an extent that half are obscured and half are exposed, allowing both positive and negative torque to be measured, with light transmission increasing in one direction and decreasing in the other.

[0025] Furthermore, the static grating 5 is mounted on the static grating sleeve 4, which is mounted on the deformable shaft 10, and the dynamic grating 6 is mounted on the dynamic grating sleeve 14, which is mounted on the deformable shaft 10. Preferably, the static grating 5 is mounted on the static grating sleeve 4 via a pin III17, and the static grating sleeve 4 is mounted on the fixed end of the deformable shaft 10 via a set screw. An oil-free bearing II18 is installed between the static grating 5 and the static grating sleeve 4, and the oil-free bearing II18 is provided on the deformable shaft 10.

[0026] The dynamic grating 6 is mounted on the dynamic grating sleeve 14 through the pin II16, and the dynamic grating sleeve 14 is mounted on the force-bearing end of the deformable shaft 10 through a set screw.

[0027] Further, refer to Figure 2 The housing 22 includes a rear cover 1, an outer shell 2 and a front cover 9; the outer shell 2 is a cylindrical shell with open ends, and the rear cover 1 and the front cover 9 are respectively installed at the open ends of the outer shell 2.

[0028] Reference Figure 2 and Figure 11 One end of the light-shielding sleeve 3 is mounted on the front cover 9, with a sealing ring I15 arranged between the two, and the other end of the light-shielding sleeve 3 is mounted on the rear cover, with a sealing ring II21 arranged between the two.

[0029] The front cover 9 and the rear cover 1 are respectively clearance-fitted with the housing 2 and connected by bolts.

[0030] Further, refer to Figure 12 and Figure 13 The micron-meter torque sensor also includes a limiter 11, which includes a positioning block 11-1 and an L-shaped support 11-2. The positioning block 11-1 is mounted on the end of the deformable shaft 10 adjacent to the light intensity detection plate 8 (defined as the force-bearing end, for example, the deformable shaft force-bearing section 103). The L-shaped support 11-2 is mounted on the front cover 9. A bolt 11-3 is screwed into the L-shaped support 11-2. The distance between the end of the bolt 11-3 and the positioning block 11-1 is adjustable. The L-shaped support has two bolt holes. By adjusting the distance between the bolt and the positioning block 11-1, the maximum torque measurement and the deformation of the deformable shaft can be limited.

[0031] In this embodiment, Based on the technical solution of the above-mentioned micro-newton-meter torque sensor, the following embodiments are provided: Example 4 Based on the above-mentioned micron-meter torque sensor, 10 -6 The measurement of torque in the mNm (1μNm) range has a linear accuracy higher than 0.3%, a dynamic response greater than 1000Hz, and a measuring range of up to 0.1 mNm.

[0032] Example 5 3.5mNm range, test data are shown in Table 1. Three sets of data were tested, and the linear accuracy was better than 0.1%, with a maximum mean absolute error of 6μNm.

[0033] Table 1. 3.5mNm range torque sensor accuracy test

[0034] Example 6 The test results of the 1mNm range are shown in Table 2. It can be seen that the linear accuracy in this range is higher than 0.3%, and the maximum mean absolute error is 4.3μNm.

[0035] Table 2. 1.0mNm range torque sensor accuracy test

[0036] The present invention has been disclosed above with reference to preferred embodiments, but this is not intended to limit the present invention. Any person skilled in the art who, without departing from the scope of the technical solution of the present invention, can make slight changes or modifications to the above-disclosed structures and technical contents to produce equivalent embodiments with equivalent changes, all of which still fall within the scope of the technical solution of the present invention.

Claims

1. A micro-newton-meter torque sensor based on photoelectric principle, comprising: A housing (22) for accommodating the light shielding sleeve (3), the static grating (5), the dynamic grating (6), the light intensity detection plate (8) and the light source (20); A deformation shaft (10) is mounted at both ends on the housing (22); a light intensity detection plate (80, a dynamic grating (6), a static grating (5) and a light source (20) are sequentially arranged along the deformation shaft (10) from the force-bearing end to the fixed end; The static grating (5) and the dynamic grating (6) are arranged along the axial gap and mounted on the deformation shaft (10); The light and dark stripes of the static grating (5) and the dynamic grating (6) are arranged in an alternating manner; The light intensity detection plate (8) and the light source (20) are respectively mounted on the light shielding sleeve (3); The light-shielding sleeve (3) is positioned by the housing (22).

2. The micron-meter torque sensor based on the photoelectric principle according to claim 1, characterized in that: A plurality of elastic columns (100) arranged along the axial direction are processed circumferentially on the middle portion of the deformable shaft (10), and a gap exists between two adjacent elastic columns (100).

3. The micron-meter torque sensor based on the photoelectric principle according to claim 1, characterized in that: The deformable shaft (10) comprises a deformable shaft force-bearing section (103), a deformable block (104) and a deformable shaft fixed section (105); one end of the deformable block (104) is connected to the deformable shaft force-bearing section (103), and the other end of the deformable block (104) is connected to the deformable shaft fixed section (105).

4. The micron-meter torque sensor based on the photoelectric principle according to claim 1, characterized in that: The interlacing angle of the light and dark stripes is 2.5°-0.2°.

5. The micron-meter torque sensor based on the photoelectric principle according to claim 1, characterized in that: described The static grating (5) is mounted on the static grating sleeve (4), the static grating sleeve (4) is mounted on the deformation shaft (10), the dynamic grating (6) is mounted on the dynamic grating sleeve (14), and the dynamic grating sleeve (14) is mounted on the deformation shaft (10).

6. The micron-meter torque sensor based on the photoelectric principle according to claim 1, characterized in that: The light source (20) is a light emitting diode.

7. The micron-meter torque sensor based on the photoelectric principle according to claim 1, characterized in that: A silicon photocell or a silicon diode is mounted on the light intensity detection board (8).

8. The micron-meter torque sensor based on the photoelectric principle according to claim 2, characterized in that: A cone (101) is processed at the fixed end of the deformable shaft (10), a threaded hole (102) is processed at the top end of the cone (101), and the cone (101) is mounted on the housing (22).

9. The micron-meter torque sensor based on the photoelectric principle according to claim 2 or 3, characterized in that: The invention also includes a limiter (11), wherein the limiter (11) includes a positioning block (11-1) and an L-shaped support (11-2), wherein the positioning block (11-1) is mounted on the force-bearing end of the deformable shaft (10), the L-shaped support (11-2) is mounted on the housing (22), and a bolt (11-3) is screwed on the L-shaped support (11-2), and the distance between the end of the bolt (11-3) and the positioning block (11-1) is adjustable.

10. The micro-newton-meter torque sensor based on the photoelectric principle according to claim 1, characterized in that: The rotation angle ±θ1 of the deformation axis 10 matches the staggered angle θ2 of the light and dark stripes of the static grating 5 and the dynamic grating 6. , k is the coefficient, k=0.5-0.8.

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