阅读说明：本技术 一种采用轴向充磁磁环的扭矩传感器 (torque sensor adopting axial magnetizing magnetic ring ) 是由 孙增智 于 2019-08-09 设计创作，主要内容包括：本发明涉及一种采用轴向磁路的扭矩传感器结构,所述扭矩传感器结构包括输入转子组件、输出转子组件以及测量组件,所述输入转子组件和输出转子组件,分别安装在通过扭力杆连接的输入轴和输出轴上；所述输入转子组件包括轴向充磁的多极磁环、支架、辐条以及输入轴环套,所述辐条设置在支架上,所述支架设置在输入轴环套和轴向充磁的多极磁环之间；所述输出转子组件包括磁通汇聚环,支架以及输出轴环套；所述磁通汇聚环设置在支架的两端,所述测量组件包括磁通集束器和磁敏元件,所述磁通集束器和磁敏元件轴向设置在磁通汇聚环之间。该方案可以使得轴向磁路类型的传感器实现工业应用,显著提高扭矩角信号的采集效率,优化信噪比。(The invention relates to a torque sensor structure adopting an axial magnetic circuit, which comprises an input rotor assembly, an output rotor assembly and a measuring assembly, wherein the input rotor assembly and the output rotor assembly are respectively arranged on an input shaft and an output shaft which are connected through a torsion bar; the input rotor assembly comprises an axially magnetized multi-pole magnetic ring, a bracket, spokes and an input shaft ring sleeve, wherein 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 comprises a magnetic flux convergence ring, a bracket and an output shaft ring sleeve; the magnetic flux gathering rings are arranged at two ends of the support, the measuring assembly comprises a magnetic flux buncher and a magneto-sensitive element, and the magnetic flux buncher and the magneto-sensitive element are axially arranged between the magnetic flux gathering rings. The scheme can enable the sensor of the axial magnetic circuit type to realize industrial application, remarkably improve the acquisition efficiency of torque angle signals and optimize the signal-to-noise ratio.)

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), 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) comprises an axially magnetized multi-pole 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-pole magnetic ring (30);

The output rotor assembly (50) comprises magnetic flux convergence rings (61,62), a bracket (52) and an output shaft ring sleeve (51); the magnetic flux convergence rings (61,62) are arranged at two ends of the bracket (52);

The measuring assembly (40) comprises a flux collector (41,42) and a magneto-sensitive element (46), wherein the flux collector (41,42) and the magneto-sensitive element (46) are axially arranged between the flux convergence rings.

2. The torque transducer structure using an axial magnetic circuit according to claim 1, wherein the input rotor assembly further comprises spokes (21) disposed on the support (20), the spokes being a connection between the input ring housing and the multi-pole magnetic ring, the number of the spokes (21) being at least one.

3. The torque transducer structure employing an axial magnetic circuit according to claim 1, wherein the input rotor assembly includes a through-hole groove (22), the through-hole groove (22) of the carrier (20) is located between the connected input collar and the multi-pole magnetic ring, and the number of the through-hole grooves (22) is at least one.

4. The torque transducer structure using an axial magnetic circuit according to claim 3, wherein the inner diameter (D1) of the through-hole groove (22) of the holder (20) is not less than the inner diameter (D1) of the output shaft collar (51), and the outer diameter (D2) of the through-hole groove (22) is not less than the outer diameter (D2) of the output shaft collar (51).

5. the torque sensor structure using an axial magnetic circuit according to claim 1, wherein the axial position of the axially magnetized multi-pole magnetic ring (30) is limited between the flux convergence rings (61) and (62) interlocked with the output shaft, and the distance (H) between the flux convergence rings (61) and (62) is equal to the magnetic ring height (H) +2 × the gap (δ).

6. The torque sensor structure employing an axial magnetic circuit according to claim 1, wherein the output rotor assembly (50) comprises a magnetic flux convergence ring (61,62), a support (52) and an output shaft ring sleeve (51), the magnetic flux convergence ring (61,62) is disposed at both ends of the support (52), the magnetic flux convergence ring is provided with a magnetic flux convergence ring collecting tooth (63), and tooth form angles θ 1 of the collecting teeth (63) of the magnetic flux convergence ring (61,62) are axially coincident.

7. The torque transducer structure employing an axial magnetic circuit according to claim 6, wherein the tooth profile angle (θ 1) of the flux collecting ring collecting tooth (63) is substantially smaller than the magnetic pole angle (θ 2) of the multi-pole magnetic ring, θ 1/θ 2 being 0.3 to 0.7, and the flux collecting ring collecting tooth (63) is parallel to the flux collecting rings (61, 62).

8. The structure of a torque transducer employing an axial magnetic circuit as in claims 1 and 6, wherein the inner diameter (31) of the axially magnetized multi-pole magnetic ring (30) is approximately equal to the tooth crest diameter (64) of the flux convergence ring pickup teeth (63), and the outer diameter (32) of the axially magnetized multi-pole magnetic ring (30) < the tooth root diameter (65) of the flux convergence ring pickup teeth (63).

9. The torque sensor structure using an axial magnetic circuit according to claim 1, wherein the flux buncher comprises a collecting surface (43), a focusing body (45) and a bending part (44), the bending part (44) connects the collecting surface (43) and the focusing body (45), the working surface (47) of the focusing body has an area substantially smaller than that of the collecting surface (43), and the center of the working surface (47) of the focusing body coincides with the sensitive center of the magneto-sensitive element (46).

Technical Field

The invention relates to a sensor, in particular to a torque sensor structure adopting an axial magnetic circuit, and belongs to the technical field of sensors.

background

The power steering system is divided into 4 types according to the installation position of a power motor: steering column power-assisted (C-EPS), pinion power-assisted (P-EPS), double pinion power-assisted (D-EPS) and rack power-assisted (R-EPS). The steering column power-assisted type steering column has the advantages of simple and compact structure, convenience in manufacturing, maintenance and low cost, and is widely applied.

The torque sensor is a key component of a column type electric power steering system, people research many types of torque sensors by using different technical principles, and only the non-contact magnetic-sensing type torque sensor is distinguished by a plurality of advantages of simple structure and good cost performance, and becomes the mainstream application at present.

Mr. of the metabolic processes of Shanghai's communication points out in the "Current foreign research situation" of his paper: most hall-type torque sensors are based on MMT technology, and representative companies include french foreo (valo), BOSH (BOSH) in germany, BI in the united states, LG in korea, and the like.

The patent CN100468024C by the moving magnet technology company describes the structure of such a sensor, in which the rotor magnet is of the radially magnetized type, and the stator ring is extended with axially directed and overlapping teeth, and the geometric design of the stator ring teeth is improved against the problem of low sensitivity of the radial magnetic circuit structure.

The non-contact magnetic-sensing torque sensor is divided into 2 types of axial magnetization and radial magnetization according to the magnetic pole orientation of a multi-pole magnetic ring. The US patent US6810336B2 shows the basic structure of 2 magnetizing types of rotor magnet rings: fig. 1 and 10 are exploded views of an axial magnetizing type, and fig. 2 is a sectional view of the axial magnetizing type. Fig. 14 is an exploded view of a radial magnetizing type, and fig. 15 is a sectional view of the radial magnetizing type.

The main difference between the 2 magnetizing type magnetic circuits is the configuration of the stator ring teeth: in the magnetic circuit of axial magnetization, the stator ring tooth is parallel to the stator ring plane, the axial position of the multipolar magnetic ring is limited between 2 stator rings linked with the output shaft, and the stator ring tooth covers the upper and lower 2 end faces of the multipolar magnetic ring; in the magnetic circuit of radial magnetization, the stator ring teeth are bent to form a right angle with the plane of the stator ring, and the inner diameter of the stator ring tooth surface is larger than the outer diameter of the multipole magnetic ring.

the acquisition efficiency of the torque angle magnetic field is a key parameter of the magnetic-sensitive torque sensor, and the 2 magnetizing types of basic structures determine that the acquisition efficiency is obviously different.

In the axial magnetizing structure, the stator rings are respectively arranged at the outer sides of the upper end surface and the lower end surface of the magnetic ring, and each collecting tooth of the upper (or lower) stator ring has the same magnetic field polarity, so that the problem of magnetic flux short circuit between adjacent teeth is solved, and the collecting efficiency is higher. In the radial magnetizing structure, the collecting teeth of 2 stator rings are distributed on the outer side of the outer diameter of the magnetic ring in a staggered mode, the polarities of magnetic fields between adjacent teeth are opposite (except for a magnetic ring 0GS shaft), and the problem of magnetic flux short circuit between the adjacent teeth exists. Therefore, the torque angle magnetic field of the sensor with the radial magnetizing structure has low acquisition efficiency and unsatisfactory signal-to-noise ratio.

Although the torque sensor with the axial magnetizing structure has the advantage of high acquisition efficiency, the trace of the torque sensor is not seen in industrial application, and only the torque sensor with the radial magnetizing structure is unique. Because the torque sensor with the axial magnetizing structure has poor installation performance, the torque sensor is not suitable for industrial application.

As is well known, a steering column of a column-type electric power steering system includes an input shaft, a torsion bar, and an output shaft, the output shaft of the steering column is a carrier of a torque sensor, and the sensor is fixed to the output shaft by interference fit of an output shaft collar and the output shaft of the steering column.

When a user installs the steering column, the ring sleeve of the output shaft assembly is firstly pressed on the output shaft of the steering column, and then the ring sleeve of the input shaft assembly is fixed on the input shaft of the steering column.

The radial magnetizing type sensor is characterized in that a circular opening formed by the inner diameter of the tooth surface of a stator ring is arranged above the ring sleeve of the output shaft assembly, and a user can press the ring sleeve of the output shaft assembly through the circular opening to fix the output shaft assembly. Then, the input shaft assembly is placed into the circular opening, a ring sleeve of the input shaft assembly is fixed on the input shaft of the steering column, and the input shaft assembly is fixed. Therefore, the input shaft assembly of the sensor of the radial magnetizing type for industrial application is a separate assembly. An illustration of input shaft assemblies can be found in FIG. 3 of CN101017115B, MMT article SAN2006-1-0939 and Non-relating torque sensors aid energy maintenance applications.

In the axial magnetizing type sensor, the axial position of a multi-pole magnetic ring needs to be arranged in the middle of 2 stator rings, and a circular opening for a user to press and connect the ring sleeve of the output shaft assembly is not formed above the ring sleeve of the output shaft assembly, so that the input shaft assembly is not allowed to be installed as an independent assembly. The sensor installation of axial magnetization type needs to assemble the magnetic flux of output shaft subassembly and assembles 2 subassemblies of ring split into upper and lower gathering: the lower gathering ring assembly comprises an output ring sleeve, a lower half shell and a lower gathering ring, and the upper gathering ring assembly comprises an upper half shell and an upper gathering ring. The 2 subassemblies have to be as follows: the lower converging ring assembly → the magnetic ring assembly → the upper converging ring assembly. Because assemble the ring split and be 2 subassemblies, can cause the installation deviation of 2 ring chip intervals that assemble, the phase deviation of 2 teeth that assemble, 2 lock between the subassembly are fixed, still can produce the contradiction of reliability and convenience, leakproofness. Therefore, a new solution to this technical problem is urgently needed.

Disclosure of Invention

The invention provides a torque sensor structure adopting an axial magnetic circuit aiming at the problems in the prior art, and the technical scheme ensures that the torque sensor of the axial magnetic circuit type can be submitted to a user in a product assembly mode through an innovative input shaft rotor structure design, so that the torque sensor of the axial magnetic circuit type with high signal acquisition efficiency and excellent signal-to-noise ratio can be industrially applied; the invention also provides design improvement on important parts of the structure of the torque sensor of the axial magnetic circuit type, so that the performance of the sensor is further optimized.

In order to achieve the above object, according to the present invention, there is provided a torque sensor structure using an axial magnetic circuit, comprising an input rotor assembly, an output rotor assembly, and a measuring assembly, the input rotor assembly and the output rotor assembly being respectively mounted on an input shaft and an output shaft connected by a torsion bar,

the input rotor assembly comprises an axially magnetized multi-pole 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-pole magnetic ring;

The output rotor assembly comprises a magnetic flux convergence ring, a bracket and an output shaft ring sleeve; the magnetic flux gathering rings are arranged at two ends of the bracket;

The measuring assembly comprises a magnetic flux buncher and a magneto-sensitive element, and the magnetic flux buncher and the magneto-sensitive element are axially arranged between the magnetic flux convergence rings.

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

At present, only the torque sensor who adopts radial magnetic circuit has got into industrial application, and its input shaft ring cover and the multipolar magnetic ring that radially magnetizes adopt direct nestification to become the input rotor subassembly of independent installation, and the relative ring plane of collection tooth that its magnetic flux assembles the ring becomes the right angle and bends, makes 2 pieces of upper and lower magnetic fluxes assemble the collection tooth radial crisscross surrounding in the outside of multipolar magnetic ring of ring, before the installation of input rotor subassembly, the magnetic flux assembles the cylindrical uncovered that the collection tooth internal diameter side of ring waited to adorn multipolar magnetic ring. When the user installs, through uncovered earlier, with output shaft ring cover pressure equipment to the output shaft of steering column on, in installing cylindrical uncovered with the input rotor subassembly again, then with input shaft ring cover and fixed to the input shaft. In the torque sensor structure of the axial magnetic circuit, the collecting teeth of the magnetic flux converging ring are overlapped with the magnetic pole surfaces of the multi-pole magnetic ring, and the input rotor assembly structure cannot be used as an independent assembly installed later, so that the torque sensor of the axial magnetic circuit cannot enter industrial application.

To solve the problem of industrial application of the torque sensor structure of the axial magnetic circuit, the structure must have a space structure for press-fitting the output shaft sleeve. In the torque sensor structure of the axial magnetic circuit, the collecting teeth of the magnetic flux converging ring of the torque sensor structure must be overlapped with the magnetic pole surfaces of the multi-pole magnetic ring, and the space for pressing the output shaft ring sleeve cannot be arranged between the magnetic flux converging ring and the multi-pole magnetic ring according to the structure of the radial magnetic circuit. The structure of the input rotor assembly is improved, the direct nesting of the input shaft ring sleeve and the multi-pole magnetic ring is changed into gap connection, and the space problem of press mounting of the output shaft ring sleeve is solved by using the connection gap.

The invention sets a support with spoke structure between the input shaft ring sleeve and the multi-pole magnetic ring of the input shaft assembly, constructs a through hole groove between the input shaft ring sleeve and the multi-pole magnetic ring through the spoke, and uses the through hole groove as a gap, thereby solving the space problem of press mounting the output shaft ring sleeve.

the spokes are connecting bodies between the input shaft ring sleeve and the multi-pole magnetic ring, the number of the spokes is at least one, otherwise, the input shaft ring sleeve and the multi-pole magnetic ring cannot be connected into a whole. The spokes need to support the load of the magnetic ring, and the spokes are symmetrically distributed, so that the balanced stress of the magnetic ring is facilitated. Therefore, the spokes are preferably distributed symmetrically or asymmetrically.

As an improvement of the present invention, the input rotor assembly includes through-hole slots, the through-hole slots of the bracket are located between the connected input shaft ring sleeve and the multi-pole magnetic ring, and the number of the through-hole slots is at least one. The invention aims to arrange the support spokes, and constructs through hole grooves between the input shaft ring sleeve and the multi-pole magnetic ring, wherein the number of the through hole grooves is synchronously changed along with the number of the spokes.

As an improvement of the invention, the inner diameter (D1) of the through hole groove of the bracket is not less than the inner diameter (D1) of the output shaft sleeve, and the outer diameter (D2) of the through hole groove is not less than the outer diameter (D2) of the output shaft sleeve. The through hole groove is a channel for press fitting the press fitting ring of the output shaft ring sleeve, the press fitting object is the output shaft ring sleeve, and the through hole groove is used for ensuring the smooth passing of the press fitting ring, so that the radial dimension of the through hole groove is related to the output shaft ring sleeve.

the axial position of the axially magnetized multi-pole magnetic ring is limited between magnetic flux convergence rings linked with the output shaft, and the distance (H) between the magnetic flux convergence rings is equal to the height (H) +2 multiplied by the gap (delta) of the magnetic ring. It can be seen from the formula that the critical dimension of the axial height of the relational sensor is limited by the height and clearance of the magnetic ring.

As an improvement of the invention, the output rotor assembly comprises a magnetic flux convergence ring, a support and an output shaft ring sleeve, wherein the magnetic flux convergence ring is arranged at two ends of the support, magnetic flux convergence ring acquisition teeth are arranged on the magnetic flux convergence ring, and tooth form angles theta 1 of the acquisition teeth of the magnetic flux convergence ring are axially overlapped.

As an improvement of the invention, the tooth profile angle (theta 1) of the collecting tooth of the magnetic flux convergence ring is significantly smaller than the magnetic pole angle (theta 2) of the multi-pole magnetic ring, theta 1/theta 2 is 0.3-0.7, and the collecting tooth of the magnetic flux convergence ring is parallel to the magnetic flux convergence ring.

In the known torque sensor structure of the axial magnetic circuit, the tooth profile angle of the collecting tooth of the magnetic flux converging ring is equal to the magnetic pole angle of the multi-pole magnetic ring, and because the magnetic induction intensity on the surface of the magnetic pole is not uniformly distributed and the magnetic induction intensity from the central axis of the magnetic pole to the boundary of the magnetic pole at the 2 side is in attenuation distribution, when theta 1/theta 2 is equal to 1, the collecting tooth of the magnetic flux converging ring can only obtain the average magnetic induction intensity on the surface of the magnetic pole. However, the tooth form angle of the collecting tooth of the magnetic flux converging ring cannot be too small, the tooth form angle is too small, the area for collecting magnetic flux is small, and efficient collection of corner magnetic signals cannot be achieved.

As an improvement of the invention, the inner diameter (31) of the axially magnetized multi-pole magnetic ring is approximately equal to the tooth crest diameter of the magnetic flux gathering ring acquisition teeth, and the outer diameter of the axially magnetized multi-pole magnetic ring is less than the tooth bottom diameter of the magnetic flux gathering ring acquisition teeth.

The tooth crest diameter of the magnetic flux convergence ring acquisition teeth is obviously smaller than the inner diameter of the multi-pole magnetic ring, and the magnetic flux convergence ring acquisition teeth can enter the inner diameter side space of the multi-pole magnetic ring and interfere with the space of the press-mounting output shaft ring sleeve. The tooth crest diameter of the collecting teeth of the magnetic flux converging ring is obviously larger than the inner diameter of the multi-pole magnetic ring, and the collecting teeth cannot completely cover the magnetic pole end face of the multi-pole magnetic ring, so that the loss of the collected magnetic signals is caused.

The outer diameter of the multi-pole magnetic ring is required to be smaller than the tooth bottom diameter of the collecting teeth of the magnetic flux converging ring, and the outer diameter of the multi-pole magnetic ring is too large, so that magnetic signals of the collecting teeth can be attenuated by the tooth bottom diameter short circuit of the collecting teeth of the magnetic flux converging ring.

As an improvement of the invention, the magnetic flux buncher comprises a collecting surface, a focusing body and a bending part,

the bending part is connected with the collecting surface and the focusing body, the area of the working surface of the focusing body is obviously smaller than that of the collecting surface, and the center of the working surface of the focusing body is coincided with the sensitive center of the magnetic sensing element.

At present, torque sensor's magnetic flux buncher has adopted the structure of 2 portions of bending more, has several not enough: 1. the occupied radial space is large. 2. Through 2 bending, the parallelism tolerance of the collecting surface and the focusing working surface of the buncher is larger, and the collecting efficiency of magnetic signals is influenced. 3. When the magnetic sensor adopts a double-sensing center, the width of the focusing working surface needs to be extended, so that the magnetic induction intensity of the focusing working surface is weakened. The buncher only provided with 1 bending part is designed, and the radial space occupation of the buncher is reduced. The area of the focusing working surface is obviously smaller than that of the collecting surface, so that the magnetic flux of the collecting surface can be focused and enhanced, and 2 focusing working surface positions can be flexibly set according to the position of the double-sensitive center of the magnetic sensitive element in redundant configuration. The 2 focusing working planes of 1 collecting plane are shared, the magnetic rotation angle signals are completely synchronous, and the difference of phase and intensity does not exist.

According to the scheme, through an innovative input shaft rotor structure design, a spoke structure for constructing a through hole groove is introduced between an input shaft sleeve and a multi-pole magnetic ring, so that a space for press-mounting an output shaft sleeve is provided, the torque sensor of an axial magnetic circuit type with high signal acquisition efficiency and excellent signal-to-noise ratio can be submitted to a user in a product assembly mode, and industrial application is realized. The scheme also carries out design improvement on important parts of the torque sensor structure of the axial magnetic circuit type, and specifically comprises the following steps of 1, giving an optimal design range of a tooth profile angle of a key element magnetic flux convergence ring acquisition tooth in the axial magnetic circuit, and an optimal design range of a convergence ring acquisition tooth profile angle (theta 1) related to a magnetic pole angle (theta 2): theta 1/theta 2 is 0.3-0.7. 2. The design principle of the radial dimension of the magnetic flux convergence ring acquisition teeth is given, the inner diameter of the axially magnetized multi-pole magnetic ring is approximately equal to the tooth crest diameter of the magnetic flux convergence ring acquisition teeth, and the outer diameter of the axially magnetized multi-pole magnetic ring is less than the tooth bottom diameter of the magnetic flux convergence ring acquisition teeth. 3. The design of a key element magnetic flux buncher in an axial magnetic circuit is improved, a bending part is adopted to connect an acquisition surface and a focusing body, and the area of a working surface of the focusing body is obviously smaller than that of the acquisition surface.

the torque sensor of the axial magnetizing magnetic ring with high acquisition efficiency is industrially applied by the scheme, the improved sensor structure not only improves the sensitivity and the signal-to-noise ratio of the sensor, but also can improve the consistency of product performance, simplify the complexity of product manufacture and user installation, and reduce the cost of product manufacture, package, transportation and user installation.

Drawings

FIG. 1 is an exploded view of a torque sensor structure employing an axial magnetic circuit;

FIG. 2 is a schematic illustration of an input shaft rotor assembly;

FIG. 3 is a schematic view of the output shaft rotor assembly;

FIG. 4 is a schematic view of a flux concentrator;

FIG. 5 is a schematic view of an axially magnetized magnetic ring;

FIG. 6 is a schematic view of a flux concentrating ring and an axially magnetized magnetic ring;

FIG. 7 is a schematic view of the installation of the measurement assembly;

FIG. 8 is a schematic view of another embodiment of an input shaft rotor assembly;

fig. 9 is a schematic view of another embodiment of a magnetic flux collector.

The specific implementation mode is as follows:

for the purpose of enhancing an understanding of the present invention, the present embodiment will be described in detail below with reference to the accompanying drawings.