A torque sensor using an axially magnetized magnetic ring

Abstract

The present invention relates to a torque sensor structure using an axial magnetic circuit, the torque sensor structure includes an input rotor assembly, an output rotor assembly and a measuring assembly, the input rotor assembly and the output rotor assembly are respectively mounted on an input shaft and an output shaft connected by a torsion bar; the input rotor assembly includes an axially magnetized multi-pole magnetic ring, a bracket, spokes and an input shaft ring sleeve, the spokes are arranged on the bracket, and the bracket is arranged between the input shaft ring sleeve and the axially magnetized multi-pole magnetic ring; the output rotor assembly includes a magnetic flux converging ring, a bracket and an output shaft ring sleeve; the magnetic flux converging ring is arranged at both ends of the bracket, and the measuring assembly includes a magnetic flux buncher and a magnetic sensitive element, and the magnetic flux buncher and the magnetic sensitive element are axially arranged between the magnetic flux converging ring. This solution can enable the axial magnetic circuit type sensor to be industrially applied, significantly improve the acquisition efficiency of the torque angle signal, and optimize the signal-to-noise ratio.

Description

Technical Field

[0001] The invention relates to a sensor, in particular to a torque sensor structure using an axial magnetic circuit, and belongs to the technical field of sensors. Background Art

[0002] Power steering systems are divided into four categories according to the installation position of the power motor: column-assisted EPS (C-EPS), pinion-assisted EPS (P-EPS), dual pinion-assisted EPS (D-EPS) and rack-assisted EPS (R-EPS). Column-assisted EPS has been widely used due to its simple and compact structure, easy manufacturing and maintenance, and low cost.

[0003] The torque sensor is a key component of the column electric power steering system. People have developed many types of torque sensors using different technical principles. Only the non-contact magnetic torque sensor stands out with its many advantages such as simple structure and good cost performance, and has become the mainstream application now.

[0004] Mr. Xie Cheng from Shanghai Jiaotong University pointed out in the "Current Status of Foreign Research" of his paper: Currently most Hall-type torque sensors are based on MMT technology, among which the more representative companies include Valeo in France, Bosch in Germany, BI in the United States, LG in South Korea, etc.

[0005] Patent CN100468024C of Mobile Magnet Technology describes the structure of this sensor, in which the rotor magnet is of the radially magnetized type, and the stator ring extends with axially pointing and overlapping teeth. In order to address the low sensitivity problem of the radial magnetic circuit structure, the geometric design of the stator ring teeth has been improved.

[0006] According to the magnetic pole orientation of the multi-polar magnetic ring, the non-contact magnetic torque sensor is divided into two types: axial magnetization and radial magnetization. U.S. Patent US6810336B2 gives the basic structure of the two types of rotor magnetic ring magnetization: Figure 1 Figure 10 is an exploded view of the axial magnetization type. Figure 2 FIG14 is an exploded view of a radial magnetization type, and FIG15 is a cross-sectional view of a radial magnetization type.

[0007] The main difference between the two types of magnetization magnetic circuits is the structure of the stator ring teeth: in the axially magnetized magnetic circuit, the stator ring teeth are parallel to the stator ring plane, the axial position of the multi-pole magnetic ring is limited between the two stator rings linked to the output shaft, and the stator ring teeth cover the upper and lower end faces of the multi-pole magnetic ring; in the radially magnetized magnetic circuit, the stator ring teeth are bent at right angles to the stator ring plane, and the inner diameter of the stator ring tooth surface is greater than the outer diameter of the multi-pole magnetic ring.

[0008] The acquisition efficiency of the torque angular magnetic field is a key parameter of the magnetic torque sensor. The basic structures of the two types of magnetization determine that the acquisition efficiency is significantly different.

[0009] In the axial magnetization structure, the stator rings are placed on the outside of the upper and lower end surfaces of the magnetic ring. The collection teeth of the upper (or lower) stator ring have the same magnetic field polarity, and there is no problem of magnetic flux short circuit between adjacent teeth, so the collection efficiency is relatively high. In the radial magnetization structure, the collection teeth of the two stator rings are staggered and distributed on the outside of the outer diameter of the magnetic ring. The magnetic field polarity between adjacent teeth is opposite (except for the 0GS axis of the magnetic ring), and there is a problem of magnetic flux short circuit between adjacent teeth. Therefore, the sensor with radial magnetization structure has a relatively low collection efficiency of torque angular magnetic field and an unsatisfactory signal-to-noise ratio.

[0010] Although the torque sensor with axial magnetization structure has the advantage of high acquisition efficiency, it has not been seen in industrial applications, and only the torque sensor with radial magnetization structure is popular. This is because the torque sensor with axial magnetization structure has poor installability and is not suitable for industrial applications.

[0011] As is known to all, the steering column of the column-type electric power steering system comprises an input shaft, a torsion bar and an output shaft. The output shaft of the steering column is the carrier of the torque sensor, and the sensor is fixed on the output shaft through an interference fit between the output shaft sleeve and the output shaft of the steering column.

[0012] When the user installs, he must first press the collar of the output shaft assembly onto the output shaft of the steering column, and then fix the collar of the input shaft assembly onto the input shaft of the steering column.

[0013] For radial magnetization type sensors, above the ring sleeve of the output shaft assembly is a circular opening surrounded by the inner diameter of the stator ring tooth surface. The user can press the ring sleeve of the output shaft assembly through the circular opening to fix the output shaft assembly. Then, put the input shaft assembly into the circular opening, fix the ring sleeve of the input shaft assembly on the input shaft of the steering column, and fix the input shaft assembly. Therefore, for radial magnetization type sensors used in industrial applications, the input shaft assembly is an independent assembly. For illustrations related to the input shaft assembly, please refer to CN101017115B Figure 3 , MMT paper SAN2006-1-0939 and Non-contacting torquesensors aim at power steering applications.

[0014] For axial magnetization type sensors, the axial position of the multi-pole magnetic ring needs to be set in the middle of the two stator rings. There is no circular opening above the ring sleeve of the output shaft assembly for the user to crimp the ring sleeve of the output shaft assembly, and the input shaft assembly is not allowed to be installed as an independent assembly. To install an axial magnetization type sensor, the magnetic flux convergence ring of the output shaft assembly needs to be split into two subassemblies of the upper and lower convergence rings: the lower convergence ring assembly includes the output ring sleeve, the lower half shell and the lower convergence ring, and the upper convergence ring assembly includes the upper half shell and the upper convergence ring. The two subassemblies must be installed in the order of: lower convergence ring assembly → magnetic ring assembly → upper convergence ring assembly. Since the convergence ring is split into two subassemblies, there will be installation deviations in the spacing between the two convergence ring pieces, phase deviations in the two convergence teeth, and the buckling fixation between the two subassemblies, which will also cause contradictions between reliability, convenience, and sealing. Therefore, a new solution is urgently needed to solve this technical problem. Summary of the invention

[0015] The present invention is aimed at the problems existing in the prior art and provides a torque sensor structure using an axial magnetic circuit. Through the innovative input shaft rotor structure design, the technical solution enables the axial magnetic circuit type torque sensor to be submitted to users in the form of a product assembly, so that the axial magnetic circuit type torque sensor with high signal acquisition efficiency and excellent signal-to-noise ratio can be industrially applied. The present invention also makes design improvements to the important components of the axial magnetic circuit type torque sensor structure, so as to further optimize the sensor performance.

[0016] In order to achieve the above object, the technical solution of the present invention is as follows: a torque sensor structure using an axial magnetic circuit, characterized in that the torque sensor structure includes an input rotor assembly, an output rotor assembly and a measuring assembly, wherein the input rotor assembly and the output rotor assembly are respectively mounted on an input shaft and an output shaft connected by a torsion bar,

[0017] The input rotor assembly comprises an axially magnetized multi-polar magnetic ring, a bracket and an input shaft ring sleeve; the bracket (20) is arranged between the input shaft ring sleeve and the axially magnetized multi-polar magnetic ring;

[0018] The output rotor assembly includes a magnetic flux converging ring, a bracket and an output shaft ring sleeve; the magnetic flux converging ring is arranged at both ends of the bracket;

[0019] The measuring assembly comprises a magnetic flux buncher and a magnetic sensitive element, wherein the magnetic flux buncher and the magnetic sensitive element are axially arranged between magnetic flux converging rings.

[0020] As an improvement of the present invention, the input rotor assembly further comprises spokes, wherein the spokes are arranged on a bracket, the spokes are connecting bodies between the input shaft ring sleeve and the multi-stage magnetic ring, and the number of the spokes is at least one.

[0021] At present, only torque sensors using radial magnetic circuits have entered industrial applications. The input shaft ring sleeve and radially magnetized multi-polar magnetic ring are directly nested to form an independently installed input rotor assembly. The collection teeth of the magnetic flux convergence ring are bent at right angles relative to the ring plane, so that the collection teeth of the upper and lower magnetic flux convergence rings are radially staggered around the outside of the multi-polar magnetic ring. Before the input rotor assembly is installed, the inner diameter side of the collection teeth of the magnetic flux convergence ring is a cylindrical opening to be installed with the multi-polar magnetic ring. When the user installs, first press the output shaft ring sleeve onto the output shaft of the steering column through the opening, then install the input rotor assembly into the cylindrical opening, and then fix the input shaft ring sleeve to the input shaft. The torque sensor structure of the axial magnetic circuit has the collection teeth of the magnetic flux convergence ring overlapping the magnetic pole surface of the multi-polar magnetic ring, and the input rotor assembly structure cannot be used as an independent component installed later, resulting in the inability of the torque sensor of the axial magnetic circuit to enter industrial applications.

[0022] To solve the industrial application problem of the torque sensor structure of the axial magnetic circuit, its structure must have a space structure for press-fitting the output shaft ring sleeve. In the torque sensor structure of the axial magnetic circuit, the collection teeth of its magnetic flux convergence ring and the magnetic pole surface of the multi-polar magnetic ring must overlap. It is impossible to set a space for press-fitting the output shaft ring sleeve between the magnetic flux convergence ring and the multi-polar magnetic ring according to the structure of the radial magnetic circuit. The present invention improves the structure of the input rotor assembly, changes the direct nesting of the input shaft ring sleeve and the multi-polar magnetic ring into a gap connection, and uses the connection gap to solve the space problem of press-fitting the output shaft ring sleeve.

[0023] The present invention arranges a bracket with a spoke structure between the input shaft ring sleeve and the multi-polar magnetic ring of the input shaft assembly, constructs a through hole groove between the input shaft ring sleeve and the multi-polar magnetic ring through the spoke, and uses the through hole groove as a gap to solve the space problem of the press-fit output shaft ring sleeve.

[0024] The spokes are the connectors between the input shaft ring and the multi-polar magnetic ring. There must be at least one spoke, otherwise the input shaft ring and the multi-polar magnetic ring cannot be connected as one. The spokes need to support the load of the magnetic ring. Symmetrical distribution of spokes is conducive to balanced force on the magnetic ring. Therefore, the spokes are preferably distributed symmetrically, but they can also be distributed asymmetrically.

[0025] As an improvement of the present invention, the input rotor assembly includes a through-hole slot, the through-hole slot of the bracket is located between the connected input shaft ring sleeve and the multi-polar magnetic ring, and the number of the through-hole slot is at least one. The purpose of setting the bracket spokes of the present invention is to construct a through-hole slot between the input shaft ring sleeve and the multi-polar magnetic ring, and the number of the through-hole slots changes synchronously with the number of spokes.

[0026] As an improvement of the present invention, the inner diameter (d1) of the through hole groove of the bracket is ≤ the inner diameter (D1) of the output shaft ring sleeve, and the outer diameter (d2) of the through hole groove is ≥ the outer diameter (D2) of the output shaft ring sleeve. The through hole groove is a channel for the press-fitting ring of the output shaft ring sleeve, and the press-fitting object is the output shaft ring sleeve. The through hole groove must ensure that the press-fitting ring passes smoothly, so the radial size of the through hole groove is associated with the output shaft ring sleeve.

[0027] As an expression of the axial correlation parameters of the present invention, the axial position of the axially magnetized multi-pole magnetic ring is limited between the magnetic flux converging ring and the output shaft, and the distance between the magnetic flux converging ring and the output shaft (H) = magnetic ring height (h) + 2 × gap (δ). It can be seen from the formula that the key dimension of the axial height of the sensor is subject to the magnetic ring height and the gap.

[0028] As an improvement of the present invention, the output rotor assembly includes a magnetic flux converging ring, a bracket and an output shaft ring sleeve. The magnetic flux converging ring is arranged at both ends of the bracket. The magnetic flux converging ring is provided with magnetic flux converging ring collecting teeth, and the tooth angle θ1 of the collecting teeth of the magnetic flux converging ring overlaps axially.

[0029] As an improvement of the present invention, the tooth angle (θ1) of the magnetic flux converging ring collecting teeth is significantly smaller than the magnetic pole angle (θ2) of the multi-polar magnetic ring, θ1 / θ2=0.3~0.7, and the magnetic flux converging ring collecting teeth are parallel to the magnetic flux converging ring.

[0030] In the known axial magnetic circuit torque sensor structure, the tooth profile angle of the magnetic flux gathering ring collection teeth is equal to the magnetic pole angle of the multi-pole magnetic ring. Since the magnetic induction intensity on the magnetic pole surface is not uniformly distributed, it is attenuated from the magnetic pole center axis to the two-side magnetic pole boundary. Therefore, when θ1 / θ2=1, the magnetic flux gathering ring collection teeth can only obtain the average magnetic induction intensity on the magnetic pole surface. However, the tooth profile angle of the magnetic flux gathering ring collection teeth cannot be too small. If the tooth profile angle is too small, the area of ​​the collected magnetic flux is also small, and the efficient collection of the angular magnetic signal cannot be achieved. The present invention proposes the optimal design range θ1 / θ2=0.3~0.7 through experiments.

[0031] As an improvement of the present invention, the inner diameter (31) of the axially magnetized multi-polar magnetic ring is approximately the tooth top diameter of the magnetic flux converging ring collecting teeth, and the outer diameter of the axially magnetized multi-polar magnetic ring is less than the tooth bottom diameter of the magnetic flux converging ring collecting teeth.

[0032] The top diameter of the magnetic flux gathering ring collection teeth is significantly smaller than the inner diameter of the multi-polar magnetic ring. The magnetic flux gathering ring collection teeth will enter the inner diameter side space of the multi-polar magnetic ring and interfere with the space of the press-fit output shaft ring sleeve. The top diameter of the magnetic flux gathering ring collection teeth is significantly larger than the inner diameter of the multi-polar magnetic ring. The collection teeth cannot fully cover the magnetic pole end face of the multi-polar magnetic ring, resulting in the loss of the collectible magnetic signal.

[0033] It is required that the outer diameter of the multi-pole magnetic ring is smaller than the tooth bottom diameter of the magnetic flux converging ring collecting teeth. If the outer diameter of the multi-pole magnetic ring is too large, the magnetic signal of the collecting teeth will be short-circuited and attenuated by the tooth bottom diameter of the magnetic flux converging ring collecting teeth.

[0034] As an improvement of the present invention, the magnetic flux buncher comprises a collecting surface, a focusing body and a bending portion.

[0035] The bending portion connects the collection surface and the focusing body, the area of ​​the working surface of the focusing body is significantly smaller than the area of ​​the collection surface, and the center of the working surface of the focusing body coincides with the sensitive center of the magnetic sensitive element.

[0036] At present, the magnetic flux buncher of the torque sensor mostly adopts a structure with two bending parts, which has several shortcomings: 1. It occupies a relatively large radial space. 2. After two bends, the parallelism tolerance of the collection surface and the focusing working surface of the buncher is too large, which affects the collection efficiency of the magnetic signal. 3. When the magnetic sensitive element adopts a dual sensitive center, it is necessary to extend the width of the focusing working surface, which causes the magnetic induction intensity of the focusing working surface to weaken. The present invention designs a buncher with only one bending part, which reduces the radial space occupied by the buncher. The area of ​​the focusing working surface is significantly smaller than the area of ​​the collection surface, which can not only focus and enhance the magnetic flux of the collection surface, but also flexibly set the positions of the two focusing working surfaces according to the positions of the dual sensitive centers of the redundantly configured magnetic sensitive elements. The two focusing working surfaces that share one collection surface have completely synchronized magnetic rotation angle signals, and there is no difference in phase and intensity.

[0037] This scheme introduces a spoke structure with a through-hole groove between the input shaft ring sleeve and the multi-pole magnetic ring through an innovative input shaft rotor structure design to provide space for the press-fit output shaft ring sleeve, so that the axial magnetic circuit type torque sensor with high signal acquisition efficiency and excellent signal-to-noise ratio can be submitted to users in the form of a product assembly to achieve industrial application. This scheme also makes design improvements to the important components of the axial magnetic circuit type torque sensor structure, as follows: 1. The optimal design range of the tooth profile angle of the flux convergence ring collection teeth, a key component in the axial magnetic circuit, is given, and the optimal design range of the tooth profile angle (θ1) of the convergence ring collection teeth associated with the magnetic pole angle (θ2) is: θ1 / θ2=0.3~0.7. 2. The radial dimension design principle of the flux convergence ring collection teeth is given, the inner diameter of the axially magnetized multi-pole magnetic ring ≈ the tooth top diameter of the flux convergence ring collection teeth, and the outer diameter of the axially magnetized multi-pole magnetic ring < the tooth bottom diameter of the flux convergence ring collection teeth. 3. The design of the flux buncher, a key component in the axial magnetic circuit, has been improved. A bending part is used to connect the collection surface and the focusing body. The area of ​​the working surface of the focusing body is significantly smaller than that of the collection surface.

[0038] This solution enables the industrial application of torque sensors with axially magnetized magnetic rings with high collection efficiency. The improved sensor structure not only improves the sensitivity and signal-to-noise ratio of the sensor, but also improves the consistency of product performance, simplifies the complexity of product manufacturing and user installation, and reduces the cost of product manufacturing, packaging, transportation and user installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is an exploded view of the torque sensor structure using an axial magnetic circuit;

[0040] Figure 2 is a schematic diagram of the input shaft rotor assembly;

[0041] Figure 3 is a schematic diagram of the output shaft rotor assembly;

[0042] Figure 4 is a schematic diagram of a flux buncher;

[0043] Figure 5 It is a schematic diagram of an axially magnetized magnetic ring;

[0044] Figure 6 It is a schematic diagram of the magnetic flux converging ring and the axial magnetizing magnetic ring;

[0045] Figure 7 It is a schematic diagram of the installation of the measuring components;

[0046] Figure 8 is a schematic diagram of another embodiment of an input shaft rotor assembly;

[0047] Fig. 9 It is a schematic diagram of another embodiment of a magnetic flux collector. DETAILED DESCRIPTION

[0048] In order to deepen the understanding of the present invention, the present embodiment is described in detail below with reference to the accompanying drawings.

[0049] Example 1: See Figure 1-Figure 7 , Figure 1The torque sensor structure of the axial magnetic circuit is shown, and the torque sensor structure includes an input rotor assembly 10, an output rotor assembly 50 and a measuring assembly 40. The input rotor assembly 10 and the output rotor assembly 50 are respectively mounted on an input shaft 01 and an output shaft 03 connected by a torsion bar 02. The input rotor assembly 10 includes an axially magnetized multi-polar magnetic ring 30, a bracket 20 and an input shaft ring sleeve 11; the bracket 20 is arranged between the input shaft ring sleeve 11 and the axially magnetized multi-polar magnetic ring 30; the output rotor assembly 50 includes magnetic flux converging rings 61, 62, a bracket 52 and an output shaft ring sleeve 51; the magnetic flux converging rings 61, 62 are arranged at both ends of the bracket 52; the measuring assembly 40 includes magnetic flux bunchers 41, 42 and a magnetic sensitive element 46, and the magnetic flux bunchers 41, 42 and the magnetic sensitive element 46 are axially arranged between the magnetic flux converging rings.

[0050] The input rotor assembly also includes a spoke 21, which is arranged on the bracket 20. The spoke is a connector between the input shaft ring and the multi-polar magnetic ring. The number of spokes 21 is at least one. The spokes 21 are preferably symmetrically distributed, but can also be asymmetrically distributed. The input rotor assembly also includes a through-hole slot 22. The through-hole slot 22 of the bracket 20 is located between the connected input shaft ring and the multi-polar magnetic ring. The number of through-hole slots 22 is at least one. The through-hole slots 22 are preferably symmetrically distributed, but can also be asymmetrically distributed. The inner diameter (d1) of the through-hole slot 22 of the bracket 20 is ≤ the inner diameter D1 of the output shaft ring 51, and the outer diameter d2 of the through-hole slot 22 is ≥ the outer diameter D2 of the output shaft ring 51. The magnetic flux collector includes a collection surface 43, a focusing surface 45, and a bending portion, and the bending portion connects the collection surface 43 and the focusing surface 45. The number and center position of the focusing surfaces of the same magnetic flux collector can be flexibly set according to the number and position of the IC sensitive center. The axial position of the axially magnetized multi-polar magnetic ring 30 is limited between the magnetic flux converging rings 61 and 62 linked to the output shaft, and the distance (H) between the magnetic flux converging rings 61 and 62 = magnetic ring height (h) + 2 × gap (δ). The magnetic flux converging ring is provided with a magnetic flux converging ring collecting tooth 63, and the tooth angle (θ1) of the magnetic flux converging ring collecting tooth 63 is associated with the magnetic pole angle (θ2) of the multi-polar magnetic ring, θ1 / θ2 = 0.3 to 0.7, the inner diameter 31 of the axially magnetized multi-polar magnetic ring 30 ≈ the tooth top diameter 64 of the magnetic flux converging ring collecting tooth 63, and the outer diameter 32 of the axially magnetized multi-polar magnetic ring 30 ≤ the tooth bottom diameter 65 of the magnetic flux converging ring collecting tooth 63.

[0051] In the above scheme, Figure 2It is a schematic diagram of the input shaft rotor assembly. In order to solve the assembly installation problem of the torque sensor using an axial magnetic ring, a bracket 20 with a spoke 21 structure is provided between the input shaft ring sleeve 11 and the multi-stage magnetic ring 30, and a through-hole groove 22 between the input shaft ring sleeve and the multi-stage magnetic ring is constructed by the spoke. It is stipulated that the number of spokes ≥ 1 and the number of through-hole grooves ≥ 1, because at least 1 through-hole groove is required for assembly installation. Example 1 adopts a structure of 2 symmetrically distributed spokes and 2 through-hole grooves. The through-hole groove 22 is the passage space for the user's crimping ring, and the object of crimping is the output shaft ring sleeve 51 of the sensor. Therefore, the radial parameters of the through-hole groove are determined by the diameters D1 and D2 of the output shaft ring sleeve, and it is required that the inner diameter of the through-hole groove (d1) is ≤ the inner diameter D1 of the output shaft ring sleeve, and the outer diameter d2 of the through-hole groove is ≥ the outer diameter D2 of the output shaft ring sleeve.

[0052] Figure 3 Schematic diagram of the output shaft rotor assembly, using an axially magnetized magnetic ring torque sensor, the multi-pole magnetic ring 30 of the input rotor assembly needs to be set between the two magnetic flux converging rings 61, 62, the magnetic flux converging ring is fixed on the output assembly bracket 52 linked to the output shaft, a working gap δ is set between the multi-pole magnetic ring and the magnetic flux converging ring, the distance between the two magnetic flux converging rings = magnetic ring height + 2 × δ, Figure 7 The positions of the flux converging ring, multi-pole magnetic ring and flux collector after installation are illustrated.

[0053] Figure 5 It is a schematic diagram of an axially magnetized magnetic ring. Figure 6 It is a schematic diagram of a flux converging ring and an axially magnetized magnetic ring. The tooth profile angle of the magnetic flux converging ring collection teeth is related to the magnetic pole angle of the multipolar magnetic ring. The optimal design range of the tooth profile angle is: θ1 / θ2=0.3~0.7. The inner diameter 31 of the axially magnetized multipolar magnetic ring 30 is ≈ the tooth top diameter 64 of the magnetic flux converging ring collection teeth 63, and the outer diameter 32 of the axially magnetized multipolar magnetic ring 30 is ≤ the tooth bottom diameter 65 of the magnetic flux converging ring collection teeth 63.

[0054] Figure 4 is a schematic diagram of a magnetic flux collector. Figure 7 It is a schematic diagram of the installation of the magnetic flux collector. There is only one bending portion 44 between the collecting surface 43 and the focusing body 45 of the magnetic flux collectors 41, 42. The bending portion 44 connects the collecting surface 43 and the focusing body 45. The area of ​​the working surface 47 of the focusing body is significantly smaller than the area of ​​the collecting surface 43. The center of the working surface 47 of the focusing body coincides with the sensitive center of the magnetic sensitive element 46.

[0055] Embodiment 2:

[0056] Figure 8This is another embodiment of the input shaft rotor assembly, which adopts a structure of three symmetrically distributed spokes and three through-hole slots. The present invention recommends that the symmetrical distribution of the spokes and through-hole slots is preferred, because the symmetrical distribution can make the crimped output shaft ring sleeve evenly stressed, and the rest of the structure and advantages are exactly the same as those of embodiment 1.

[0057] Embodiment 3:

[0058] Fig. 9 This is another embodiment of the magnetic flux collector. Similar to the first embodiment, the magnetic flux collector has only one collection surface 43 and one bending portion 44, but has two focusing bodies 45. The two focusing working surfaces share one collection surface, and the positions of the two focusing working surfaces can be flexibly set according to the positions of the dual sensitive centers of the redundantly configured magnetic sensing elements. The two focusing working surfaces share one collection surface, and the magnetic rotation angle signals are completely synchronized, and there is no difference in phase and intensity.

[0059] The present invention can also combine at least one of the technical features described in Examples 2 and 3 with Example 1 to form a new implementation. The remaining structures and advantages are exactly the same as those of Example 1.

[0060] It should be noted that the above embodiments are not intended to limit the protection scope of the present invention, and equivalent changes or substitutions made on the basis of the above technical solutions all fall within the protection scope of the claims of the present invention.

Claims

1. A torque sensor structure using an axial magnetic circuit, characterized in that: The torque sensor structure comprises an input rotor assembly (10), an output rotor assembly (50) and a measuring assembly (40), wherein the input rotor assembly (10) and the output rotor assembly (50) are respectively mounted on an input shaft (01) and an output shaft (03) connected via a torsion bar (02). The input rotor assembly (10) comprises an axially magnetized multi-polar magnetic ring (30), a first bracket (20) and an input shaft ring sleeve (11); the first bracket (20) is arranged between the input shaft ring sleeve (11) and the axially magnetized multi-polar magnetic ring (30); The output rotor assembly (50) comprises a first magnetic flux converging ring (61), a second magnetic flux converging ring (62), a second bracket (52) and an output shaft ring sleeve (51); the first magnetic flux converging ring (61) and the second magnetic flux converging ring (62) are arranged at two ends of the second bracket (52); The measuring assembly (40) comprises a magnetic flux buncher (41, 42) and a magnetic sensitive element (46), wherein the magnetic flux buncher (41, 42) and the magnetic sensitive element (46) are axially arranged between magnetic flux converging rings; The input rotor assembly further comprises a spoke (21), the spoke being arranged on the first bracket (20), the spoke being a connector between the input shaft ring sleeve and the multipolar magnetic ring, the number of the spoke (21) being at least one, the axial position of the axially magnetized multipolar magnetic ring (30) being limited between a first magnetic flux converging ring (61) and a second magnetic flux converging ring (62) linked to the output shaft, the distance (H) between the first magnetic flux converging ring (61) and the second magnetic flux converging ring (62) being equal to the magnetic ring height (h) + 2× the gap (δ), The output rotor assembly (50) comprises a first magnetic flux converging ring (61), a second magnetic flux converging ring (62), a second bracket (52) and an output shaft ring sleeve (51); the first magnetic flux converging ring (61) and the second magnetic flux converging ring (62) are arranged at two ends of the second bracket (52); magnetic flux converging ring collecting teeth (63) are arranged on the magnetic flux converging rings; the tooth profile angles θ1 of the collecting teeth (63) of the first magnetic flux converging ring (61) and the second magnetic flux converging ring (62) are axially overlapped; The tooth profile angle θ1 of the magnetic flux converging ring collecting teeth (63) is significantly smaller than the magnetic pole angle θ2 of the multi-polar magnetic ring, θ1 / θ2=0.3-0.7, and the magnetic flux converging ring collecting teeth (63) are parallel to the first magnetic flux converging ring (61) and the second magnetic flux converging ring (62). The inner diameter (31) of the axially magnetized multi-polar magnetic ring (30) is equal to the tooth top diameter (64) of the magnetic flux converging ring collecting teeth (63), and the outer diameter (32) of the axially magnetized multi-polar magnetic ring (30) is less than the tooth bottom diameter (65) of the magnetic flux converging ring collecting teeth (63). The magnetic flux buncher comprises a collecting surface (43), a focusing body (45) and a bending portion (44), wherein the bending portion (44) connects the collecting surface (43) and the focusing body (45), the area of ​​the working surface (47) of the focusing body is significantly smaller than the area of ​​the collecting surface (43), and the center of the working surface (47) of the focusing body coincides with the sensitive center of the magnetic sensitive element (46).

2. The torque sensor structure using an axial magnetic circuit according to claim 1, characterized in that: The input rotor assembly comprises a through hole slot (22), the through hole slot (22) of the first bracket (20) is located between the connected input shaft ring sleeve and the multi-polar magnetic ring, and the number of the through hole slot (22) is at least one.

3. The torque sensor structure using an axial magnetic circuit according to claim 2 is characterized in that: The inner diameter (d1) of the through hole groove (22) of the first bracket (20) is less than or equal to the inner diameter (D1) of the output shaft ring sleeve (51), and the outer diameter (d2) of the through hole groove (22) is greater than or equal to the outer diameter (D2) of the output shaft ring sleeve (51).

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