A hollow tubular structure torque sensor for a resistance strain type middle motor

Abstract

This utility model relates to a resistance strain gauge type hollow tubular torque sensor for a mid-mounted motor, belonging to the technical field of electric-assisted bicycles. The utility model includes a Hall element board, a static circuit board, a dynamic circuit board, an outer cover, a magnetic ring, and a resistance strain gauge. The Hall element board is connected to the static circuit board and mates with the magnetic ring. The static circuit board mates with the dynamic circuit board, and the static circuit board is fixed inside the outer cover. Its structural features include: an elastic body and a one-way valve base. The elastic body is threadedly connected to the one-way valve base. The dynamic circuit board and the magnetic ring are both fixed to the elastic body. The resistance strain gauge is adhered to the elastic body. A bearing is installed between the elastic body and the outer cover. The elastic body and the outer cover are abutted and fixed by a retaining spring. The outer wall of the outer cover is provided with a cover locking protrusion to prevent rotation of the outer cover. The static circuit board is connected to a signal line for signal output.

Description

Technical Field

[0001] This utility model relates to a resistance strain gauge type hollow tubular torque sensor for a mid-mounted motor, belonging to the field of electric-assisted bicycle technology. Background Technology

[0002] The signal transmission methods of the mid-mounted torque sensor can be divided into two main categories: wired transmission and wireless transmission. Currently, the application and prospects focus more on wireless transmission, which can be achieved using infrared signal tubes and wireless transmitter and receiver modules.

[0003] In existing technologies, the elastomer and one-way actuator base in wirelessly transmitted mid-mounted torque sensors are often integrated structures made of the same material. This is done to facilitate production and reduce processing costs. However, since the functions of the elastomer and the one-way actuator base are completely different, the materials required for them may not be the same. If these two different functional components are made of the same material and processed using the same techniques, the product's performance will be compromised. If the hardness and wear resistance requirements of the one-way actuator base are met, the toughness, deformation, and resilience characteristics of the elastomer cannot be satisfied; conversely, if the necessary technical conditions of the elastomer are met, the technical parameters of the one-way actuator base cannot be met.

[0004] The two differ significantly in their material selection. As a result, the centrally located torque sensor with an integrated structure of elastomer and one-way valve base is generally not suitable for practical applications, especially in cutting-edge technology fields that require high sensitivity and stability. Utility Model Content

[0005] The purpose of this invention is to overcome the above-mentioned deficiencies in the prior art and to provide a resistance strain gauge type hollow tubular torque sensor for a mid-mounted motor with a reasonable structural design.

[0006] The technical solution adopted by this utility model to solve the above problems is as follows: This resistance strain gauge type hollow tubular structure torque sensor for a mid-mounted motor includes a Hall element plate, a static circuit board, a dynamic circuit board, an outer cover, a magnetic ring, and a resistance strain gauge. The Hall element plate is connected to the static circuit board, and the Hall element plate cooperates with the magnetic ring. The static circuit board cooperates with the dynamic circuit board, and the static circuit board is fixed inside the outer cover. Its structural features are: it also includes an elastic body and a one-way valve base. The elastic body and the one-way valve base are connected by threads or keys. The dynamic circuit board and the magnetic ring are both fixed on the elastic body, and the resistance strain gauge is pasted on the elastic body.

[0007] Furthermore, a bearing is installed between the elastomer and the outer cover.

[0008] Furthermore, the elastomer and the outer cover are fixed together by a retaining spring.

[0009] Furthermore, a spline is provided on one side of the inner wall of the elastomer.

[0010] Furthermore, the static circuit board is connected to the signal line for electrical signal output.

[0011] Furthermore, the outer wall of the outer cover is provided with a cover locking protrusion to prevent the outer cover from rotating.

[0012] Compared with the prior art, this utility model has the following advantages: The resistance strain gauge type hollow tubular structure torque sensor for a mid-mounted motor sets the elastomer and the one-way valve base as separate structures, allowing for the selection of materials that meet the technical characteristics of the workpiece for separate processing. Furthermore, during assembly, the two are connected by threads or keys, which can simultaneously satisfy the characteristics of the elastomer in terms of toughness, deformation, and resilience, as well as the characteristics of the one-way valve base in terms of hardness and wear resistance. In addition, it can improve the product quality qualification rate of the assembly, reduce the defect rate and scrap rate, and reduce processing and manufacturing costs. Attached Figure Description

[0013] Figure 1 This is a cross-sectional structural schematic diagram of a resistance strain gauge type hollow tubular torque sensor for a mid-mounted motor, according to an embodiment of this utility model.

[0014] In the diagram: 1. Snap ring; 2. Hall element board; 3. Static circuit board; 4. Dynamic circuit board; 5. Bearing; 6. Outer cover; 7. Magnetic ring; 8. Resistance strain gauge; 9. Elastomer; 10. One-way valve base; 11. Cover locking protrusion; 12. Output signal line. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and through embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0016] Example

[0017] See Figure 1As shown in the accompanying drawings, the structures, proportions, sizes, etc., depicted in this specification are merely for illustrative purposes to aid those skilled in the art and to provide a clear understanding. They are not intended to limit the scope of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of this invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the use of terms such as "upper," "lower," "left," "right," "middle," and "one" in this specification is solely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0018] The resistance strain gauge type hollow tubular structure torque sensor for a mid-mounted motor in this embodiment includes a Hall element board 2, a static circuit board 3, a dynamic circuit board 4, an outer cover 6, a magnetic ring 7, a resistance strain gauge 8, an elastomer 9, and a one-way valve base 10. The Hall element board 2 is connected to the static circuit board 3, the Hall element board 2 is coupled to the magnetic ring 7, and the static circuit board 3 is coupled to the dynamic circuit board 4.

[0019] In this embodiment, the static circuit board 3 is fixed inside the outer cover 6, the elastic body 9 is connected to the one-way valve base 10 by threads or keys, the dynamic circuit board 4 and the magnetic ring 7 are both fixed on the elastic body 9, the resistance strain gauge 8 is pasted on the elastic body 9, and the two dynamic circuit boards 4 and the static circuit board 3 are kept relatively parallel and have a certain gap.

[0020] In this embodiment, a bearing 5 is installed between the elastomer 9 and the outer cover 6 to maintain the mutual rotation between the outer cover 6 and the elastomer 9, ensuring stable concentricity and low resistance. The elastomer 9 and the outer cover 6 are fixed by a retaining spring 1. The outer wall of the outer cover 6 is provided with a cover locking protrusion 11 to prevent the outer cover 6 from rotating. The static circuit board 3 is connected to the signal line for electrical signal output. A spline is provided on one side of the inner wall of the elastomer 9.

[0021] In this embodiment, a coil is fixedly installed on both the static circuit board 3 and the dynamic circuit board 4. The coil on the static circuit board 3 is a power transmitting coil, and the coil on the dynamic circuit board 4 is a power induction receiving coil.

[0022] In this embodiment, the static circuit board 3 is equipped with a combination of components for receiving infrared photoelectric signals, and the dynamic circuit board 4 is equipped with a combination of infrared phototubes for emitting torque electrical signals.

[0023] Specifically, the resistance strain gauge type hollow tubular torque sensor of the central motor can limit the outer cover 6 through the set cover locking protrusion 11. During operation, the relative rotation of the elastic body 9, the one-way valve base 10 and the outer cover 6 can realize the detection of torque and pedal frequency signals. The detected torque and pedal frequency signals can be output through the signal line.

[0024] To significantly improve signal acquisition, signal regularity, linear variables, and deformation space, the elastic body 9 and the one-way valve base 10 in this resistance strain gauge type hollow tubular torque sensor for a mid-mounted motor are designed as separate structures. Different materials are used to complete the elastic body 9 and the one-way valve base 10 to ensure that the elastic body 9 can guarantee deformation and toughness, while the one-way valve base 10 can guarantee hardness and wear resistance. During installation, the elastic body 9 and the one-way valve base 10 are fastened with threads. Furthermore, the strain area of ​​the elastic body 9 adopts a spoke shape to maximize the deformation space. Resistance strain gauges 8 are set for each spoke, with an optimal configuration of 3-4 spokes. The width and thickness of the spokes can be adjusted according to different variables.

[0025] In the diagram, GND represents the negative terminal of the ground wire (-), torque represents the electrical signal output by the torque sensor, cadence represents the pulse signal output by the rotation of the central shaft, and 5V represents the positive terminal of the power supply (+).

[0026] Brief introduction to the working principle of the sensor:

[0027] The splined end of the inner hole of the elastomer 9 is first inserted into the matching central shaft, so that the spline of the inner hole of the elastomer 9 meshes with the spur key on the central shaft. At this time, rotating the central shaft will drive the elastomer 9 to rotate together. The outer wall of the outer cover 6 is provided with a cover locking protrusion 11. When the cover locking protrusion 11 is engaged with the groove of the motor cavity shell, it can stop the outer cover 6 from rotating. At this time, the outer cover 6 rotates with the central shaft, while the outer cover 6 is locked and stationary, so that the static circuit board 3 and the dynamic circuit board 4 inside the elastomer 9 rotate in a space that is parallel to each other. The external power supply is sent to the power induction coil on the static circuit board 3 through the output signal line 12. The coil emits an electrical energy signal, which is received by the power receiving coil on the dynamic circuit board 4, which is kept at a relatively parallel gap, and converted into DC power for use by the internal circuit of the elastomer 9. The coils and circuits on the static circuit board 3 and the dynamic circuit board 4 complete the function of wireless power transmission from the outside to the inside of the rotating elastomer 9.

[0028] The working principle of the torque sensor is as follows: One end of the elastic body 9 with internal splines is inserted into the matching bottom shaft, where it meshes with the spur key on the bottom shaft. Rotating the bottom shaft will drive the elastic body 9 to rotate synchronously. The other end of the elastic body 9, namely the one-way valve base 10, is ultimately linked to the bicycle chainring through the wedge clutch assembly. That is, when a person pedals, the bottom shaft rotates, and the bottom shaft drives the elastic body 9 to rotate synchronously through the support key on the shaft. Since the one-way valve base 10 is connected to the chainring, this end of the chainring becomes the resistance to the rotation of the bottom shaft and the elastic body 9. For the structure of the elastic body 9, one end of the spline teeth rotates synchronously with the bottom shaft, while the other end of the one-way valve base 10, connected to the chainring and the chain, generates resistance, causing the elastic body 9 to undergo torsional deformation. This deformation is sensed by the resistance strain gauge 8 attached to the elastic body 9 and converted into an electrical signal output through the circuit.

[0029] The static circuit board 3 and the dynamic circuit board 4 also have the function of wireless transmission of torque electrical signals. That is, the dynamic circuit board 4 is equipped with several phototube devices, which convert the torque signal detected by the resistance strain gauge 8 measurement circuit into photoelectric wave signals and transmit them. The photoelectric wave receiving circuit composed of several phototube devices installed on the static circuit board 3 receives the signals and then converts them into electrical signals for transmission, thus realizing the function of wireless transmission of electrical signals in the elastic body 9.

[0030] The working principle of cadence signal detection: A magnetic ring 7 is installed on the central shaft of the torque sensor. Magnets with alternating N and S poles are distributed on the outer diameter surface of the magnetic ring 7. It rotates with the central shaft. Corresponding to it is the Hall element board 2. When the central shaft drives the magnetic ring 7 to rotate, the corresponding Hall element board 2 detects the rotation signal and outputs the signal in the form of a pulse signal.

[0031] Furthermore, it should be noted that the specific embodiments described in this specification may differ in the shape and name of their components. The above description is merely illustrative of the structure of this utility model. All equivalent or simple variations made based on the structure, features, and principles described in this utility model are included within the protection scope of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not deviate from the structure of this utility model or exceed the scope defined by the claims, all of which should fall within the protection scope of this utility model.

Claims

1. A hollow tubular structure torque sensor for a resistance strain type middle motor, comprising a Hall element plate (2), a static circuit board (3), a dynamic circuit board (4), an outer cover (6), a magnetic ring (7) and a resistance strain gauge (8), the Hall element plate (2) is connected with the static circuit board (3), the Hall element plate (2) is matched with the magnetic ring (7), the static circuit board (3) is matched with the dynamic circuit board (4), and the static circuit board (3) is fixed in the outer cover (6), characterized in that: It also includes an elastomer (9) and a one-way valve base (10), the elastomer (9) and the one-way valve base (10) are connected by threads or keys, the dynamic circuit board (4) and the magnetic ring (7) are both fixed on the elastomer (9), and the resistance strain gauge (8) is attached to the elastomer (9).

2. The resistance strain gauge type hollow tubular structure torque sensor for a centrally located motor according to claim 1, characterized in that: A bearing (5) is installed between the elastomer (9) and the outer cover (6).

3. The resistance strain gauge type hollow tubular structure torque sensor for a centrally located motor according to claim 1, characterized in that: The elastomer (9) and the outer cover (6) are fixed together by a retaining spring (1).

4. The resistance strain gauge type hollow tubular structure torque sensor for a centrally located motor according to claim 1, characterized in that: The inner wall of one side of the elastomer (9) is provided with a spline.

5. The resistance strain gauge type hollow tubular structure torque sensor for a centrally located motor according to claim 1, characterized in that: The static circuit board (3) is connected to the signal line for electrical signal output.

6. The resistance strain gauge type hollow tubular structure torque sensor for a centrally located motor according to claim 1, characterized in that: The outer wall of the outer cover (6) is provided with a cover locking protrusion (11) to prevent the outer cover (6) from rotating.

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