Center shaft torque sensor with limiting function

Abstract

The utility model relates to a center shaft torque sensor with a limiting function, and belongs to the field of power-assisted bicycles. The device comprises a middle shaft, a left bearing seat, a bearing, a protective sleeve, a right five-way seat, an elastic body, a needle bearing and a strain gauge, the two ends of the protective sleeve are connected with the left bearing seat and the right five-way seat respectively, the bearing is installed between the left bearing seat and the middle shaft, the needle bearing is installed between the elastic body and the middle shaft, and the strain gauge is installed between the elastic body and the middle shaft. The elastic body is located in the right five-way seat, the strain gauge is pasted on the elastic body, two ends of the elastic body are respectively a fixed end and a free end, and the elastic body is structurally characterized in that the fixed end of the elastic body is fixed with the right five-way seat, the free end of the elastic body is provided with a limiting convex rib, and the limiting convex rib and the elastic body are of an integrated structure.

Description

Technical Field

[0001] The utility model relates to a bottom bracket torque sensor with a limiting function, belonging to the field of assisted pedal bicycles. Background Technique

[0002] The bottom bracket torque sensor is applied to a bicycle with a chain drive using a resistive strain cantilever beam elastic body structure. A chain is used to pull between the rear axle and the bottom bracket of the bicycle, generating a pulling force from the rear axle to the bottom bracket. Taking this pulling force as information, through the detection principle of the resistive strain sensor, the displacement data of the pulling force on the elastic body is converted into the magnitude of the electric quantity. When the pedal bottom bracket rotates, the free end of the elastic body will generate displacement in all four directions of up, down, left, and right, thus reducing its service life. Installing a limiting snap ring at the free end of the elastic body can prevent the bottom bracket from generating displacement in the up, down, and right directions, enabling the bottom bracket to only generate displacement to the left.

[0003] For example, the Chinese patent document with the patent number 2023234179067 in the prior application provides a torque sensor with a cantilever beam structure. The limiting snap ring and the elastic body in the above patent document are set as a split structure. When assembling, the limiting snap ring and the elastic body need to be installed with screws, which has the disadvantages of being prone to loosening, poor concentricity, and complex processing. At the same time, the fixed end of the elastic body in the above prior art is connected to the right bottom bracket seat with screws, and it is difficult to ensure the concentricity between the elastic body and the right bottom bracket seat during installation. In addition, the needle roller bushing and the elastic body are also set as a split structure, resulting in an increase in the number of parts, inconvenient installation, and high processing costs. Content of the Utility Model

[0004] The purpose of the utility model is to overcome the above deficiencies existing in the prior art, and to provide a bottom bracket torque sensor with a limiting function and a reasonable structural design.

[0005] The technical solution adopted by the utility model to solve the above problems is: the bottom bracket torque sensor with a limiting function includes a bottom bracket, a left bearing seat, a bearing, a protective sleeve, a right bottom bracket seat, an elastic body, a needle roller bearing, and a strain gauge. Both ends of the protective sleeve are respectively connected to the left bearing seat and the right bottom bracket seat. The bearing is installed between the left bearing seat and the bottom bracket. The needle roller bearing is installed between the elastic body and the bottom bracket. The elastic body is located inside the right bottom bracket seat. The strain gauge is pasted on the elastic body. The two ends of the elastic body are respectively a fixed end and a free end. Its structural feature is that the fixed end of the elastic body is fixed to the right bottom bracket seat, and a limiting rib is arranged outside the free end of the elastic body. The limiting rib and the elastic body are set as an integral structure.

[0006] Further, the central axis torque sensor further includes a circuit board, a magnetic ring, and a waterproof signal line. The magnetic ring is fixed on the central axis, the circuit board is fixed at the fixed end of the elastomer, and the magnetic ring cooperates with the circuit board. The circuit board is connected to the waterproof signal line.

[0007] Further, the bearing is installed on the central axis through a shaft circlip A and a shaft circlip B.

[0008] Further, the needle roller bearing is installed on the central axis through a needle roller bearing circlip.

[0009] Further, a rubber ring is installed on the central axis, and the rubber ring contacts the needle roller bearing.

[0010] Further, an adjusting nut is installed on the right bottom bracket seat.

[0011] Further, a waterproof rubber cap is installed between the right bottom bracket seat and the free end of the elastomer.

[0012] Further, a chainring lock nut is installed on the central axis.

[0013] Further, the limiting rib is arranged in a C-shaped structure.

[0014] Further, a needle roller shaft sleeve is integrally arranged inside the free end of the elastomer, and the needle roller shaft sleeve cooperates with the needle roller bearing.

[0015] Further, a wire routing hole for leading out the waterproof signal line is formed inside the elastomer.

[0016] Compared with the prior art, the present utility model has the following advantages: In the central axis torque sensor with a limiting function, the limiting rib and the elastomer are integrally arranged, so there is no need to assemble the limiting rib and the elastomer, which can avoid loosening between the limiting rib and the elastomer, improve the concentricity of the limiting rib and the elastomer, and make processing more convenient; The fixed end of the elastomer and the right bottom bracket seat are tightly installed in an interference fit manner, which can improve the concentricity of the elastomer and the right bottom bracket seat, enhance the reliability, and improve the stability and service life during use, making the assembly simpler; The needle roller bearing sleeve and the elastomer are set as an integral structure, which can reduce the number of parts, improve the concentricity, and make installation more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the front view structural schematic diagram of the central axis torque sensor with a limiting function according to an embodiment of the present utility model.

[0018] Figure 2 is the right view structural schematic diagram of the central axis torque sensor with a limiting function according to an embodiment of the present utility model.

[0019] In the figure: central axis 1, shaft circlip A 2, left bearing seat 3, bearing 4, shaft circlip B 5, protective sleeve 6, circuit board 7, right bottom bracket seat 8, elastomer 9, rubber ring 10, adjusting nut 11, needle roller bearing 12, waterproof rubber cap 13, needle roller bearing circlip 14, magnetic ring 15, strain gauge 16, waterproof signal wire 17, chainring locking nut 18, limiting rib 19. Detailed implementation mode

[0020] The following further details the present utility model in conjunction with the accompanying drawings and through embodiments. The following embodiments are explanations of the present utility model, and the present utility model is not limited to the following embodiments.

[0021] Embodiment

[0022] See Figures 1 to 2 As shown, it should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions under which the present utility model can be implemented. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the efficacy that the present utility model can produce and the purpose that can be achieved, should still fall within the scope covered by the technical content disclosed in the present utility model. At the same time, if terms such as "upper", "lower", "left", "right", "middle", and "one" are cited in this specification, they are only for the convenience of clear narration and are not used to limit the scope under which the present utility model can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present utility model can be implemented.

[0023] The central axis torque sensor with a limiting function in this embodiment includes a central axis 1, a left bearing seat 3, a bearing 4, a protective sleeve 6, a circuit board 7, a right bottom bracket seat 8, an elastomer 9, a needle roller bearing 12, a magnetic ring 15, a strain gauge 16, and a waterproof signal wire 17.

[0024] In this embodiment, both ends of the protective sleeve 6 are respectively connected to the left bearing seat 3 and the right bottom bracket seat 8. The bearing 4 is installed between the left bearing seat 3 and the central axis 1. The needle roller bearing 12 is installed between the elastomer 9 and the central axis 1. The elastomer 9 is located inside the right bottom bracket seat 8. A wire routing hole for leading out the waterproof signal wire 17 is provided inside the elastomer 9.

[0025] The strain gauge 16 in this embodiment is pasted on the elastomer 9, and the two ends of the elastomer 9 are respectively a fixed end and a free end. The fixed end of the elastomer 9 is tightly fitted with the right five-way seat 8 in an interference fit manner, which can improve the concentricity of the elastomer 9 and the right five-way seat 8, enhance reliability, and improve the stability and life of use, making assembly simpler; a limiting rib 19 is arranged outside the free end of the elastomer 9, and the limiting rib 19 is arranged in a C-shaped structure. The limiting rib 19 and the elastomer 9 are an integrated structure, the magnetic ring 15 is fixed on the central axis 1, the circuit board 7 is fixed on the fixed end of the elastomer 9, and the magnetic ring 15 cooperates with the circuit board 7, and the circuit board 7 is connected to the waterproof signal line 17; a needle roller sleeve is arranged integrally with the free end of the elastomer 9, and the needle roller sleeve cooperates with the needle roller bearing 12.

[0026] The bearing 4 in this embodiment is installed on the middle shaft 1 through the shaft retaining spring A 2 and the shaft retaining spring B 5, the needle bearing 12 is installed on the middle shaft 1 through the needle bearing retaining spring 14, a rubber ring 10 is installed on the middle shaft 1, the rubber ring 10 is in contact with the needle bearing 12, an adjusting nut 11 is installed on the right five-way seat 8, a waterproof rubber cap 13 is installed between the right five-way seat 8 and the free end of the elastomer 9, and a chainring locking nut 18 is installed on the middle shaft 1.

[0027] Specifically, the fixed end of the elastic body 9 is fastened to the right five-way seat 8, and the free end of the elastic body 9 is in sliding contact with the middle shaft 1 through the needle bearing 12. The working mode of the entire elastic body 9 is a cantilever beam structure, and the free end moves with the radial shaking of the middle shaft 1.

[0028] In order to prevent the free end of the elastic body 9 from swaying in the circle as the central axis 1 rotates under force, a limiting rib 19 is integrally provided on the elastic body 9. The limiting rib 19 is arranged in a C-shaped structure, which can limit the central axis 1 in the upper, lower and right directions, so that the central axis 1 can only move freely in the spatial range of the left direction during the rotation process. Figure 2 shown.

[0029] A magnetic ring 15 is fixedly mounted on the middle axis 1, and the magnetic ring 15 rotates synchronously with the middle axis 1. A circuit board 7 with a Hall element is mounted at the corresponding position of the outer circle of the magnetic ring 15. The Hall element collects the magnetic pole signals of the N and S poles emitted by the outer circle of the magnetic ring 15 when the magnetic ring 15 rotates, and converts the signals into pulse electrical signals for output. The frequency of the pulsating electrical signals is the frequency of rotation of a person pedaling a bicycle. The pedaling frequency collection circuit can also simultaneously judge the forward rotation and reverse pedaling functions of a person pedaling a bicycle, so as to cooperate to complete the limitation that the forward pedaling has power assistance function, and the reverse pedaling has no signal power assistance.

[0030] Fixed to the right side of the bottom bracket of the bicycle is the right bottom bracket seat 8. The right bottom bracket seat 8 is of a cylindrical structure. There is a thread on the outer diameter of the cylinder. At the end of the thread, an adjusting nut 11 is installed. The thread on the outer diameter of the cylinder is fitted and fastened with the right threaded hole on the right side of the bicycle bottom bracket. A hole is drilled at the center of the left side wall of the inner diameter of the cylinder to pass through the bottom bracket spindle 1. The fixed end of the elastic body 9 is fixed on the left side wall of the inner diameter of the cylinder of the right bottom bracket seat 8. The head of the free end of the elastic body 9 is installed with a needle roller bearing 12. The needle roller bearing 12 contacts the bottom bracket spindle 1. The bottom bracket spindle 1 can rotate freely by using the needle roller bearing 12, or can rotate with a small circular swing under the guidance of a lateral force. Of course, during the rotation of the bottom bracket spindle 1, when it sways under the influence of an external force, the free end of the elastic body 9 generates a displacement through the needle roller bearing 12, thus creating the necessary conditions for detecting the torque magnitude information during the rotation process.

[0031] As Figure 2 shown, the fixed end of the elastic body 9 is coaxial with the inner hole of the right bottom bracket seat 8 and is positioned and fixed on the inner side wall of the right bottom bracket seat 8. The free end of the elastic body 9 is in radial rolling fit with the bottom bracket spindle 1 through the needle roller bearing 12 and can rotate freely and concentrically without the action of a lateral force. When the exposed square taper part of the bottom bracket spindle 1 is subjected to lateral forces from above, below, left, and right, the needle roller bearing 12 will also drive the free end of the elastic body 9 to displace and sway up, down, left, and right.

[0032] Normally, the force we need to collect is the force generated when a person pedals the crank to drive the chainring on the bottom bracket spindle 1 to rotate, and the chainring rotates to drive the bicycle rear wheel to roll through the chain. While the chain drags the rear wheel to roll, the rear wheel also gives a reverse pulling force to the bottom bracket spindle 1 in the direction of the rear wheel through the chain. This reverse pulling force and the force that the chainring rotates to drive the bicycle rear wheel to roll are forces with equal magnitudes and opposite directions.

[0033] Because the free end of the elastic body 9 is suspended in the air, when the bottom bracket spindle 1 rotates and the chainring pulls the chain to drive the rear wheel to roll, the pulling chain also gives a reverse pulling force to the bottom bracket spindle 1 fixed with the chainring. This reverse pulling force causes the bottom bracket spindle 1 to displace in the direction of the rear wheel. The magnitude of the displacement of the square taper part of the bottom bracket spindle 1 is proportional to the magnitude of the force that the chain drags the rear wheel to roll.

[0034] From Figure 2 it can be seen that the chain pulling direction between the bottom bracket spindle 1 and the rear wheel is the direction of the displacement movement of the elastic body 9 under force, and an open movement gap is required. Except for the left displacement direction where a certain movement gap needs to be reserved, there is no reverse pulling force from the rear wheel in the other three direction regions of up, down, and right. That is, except for the need to reserve a certain displacement space in the chain pulling movement direction, the free end of the elastic body 9 and the other direction regions of the circumference of the right bottom bracket seat 8 can be locked with each other, and there is no need to have a sliding gap space. As Figure 2As shown, a limiting rib 19 is integrally provided on the free end of the elastic body 9. In this way, when a person pedals a bicycle, the crank caused by the person's foot effectively limits and controls the shaking of the middle axis 1 in the upper, lower and right directions, thereby making the rotation of the middle axis 1 more stable and extending its service life.

[0035] The magnetic ring 15 is installed and fixed on the middle shaft 1 at the position with the smallest swing amplitude. The N and S magnetic poles are evenly distributed on the outer circumference of the magnetic ring 15. A cadence sensor is combined with the Hall element and its pulse generating circuit, positive and negative discrimination circuit, etc. on the corresponding circuit board 7. The magnetic ring 15 is installed and fixed on the middle shaft 1 and rotates synchronously with the middle shaft 1. The Hall element and its circuit on the circuit board 7 can sense and detect the speed of the middle shaft rotation and whether the middle shaft chain disc is rotating forward or reverse. The cadence sensor outputs the cadence signal and the instantaneous positive and negative rotation signal of the middle shaft chain disc through the waterproof signal line 17.

[0036] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the utility model. All equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the utility model are included in the protection scope of the utility model patent. Technicians in the technical field of the utility model can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the utility model or exceed the scope defined by the claims, they should all fall within the protection scope of the utility model.

Claims

1. A middle shaft torque sensor with a limit position function, comprising a middle shaft (1), a left bearing seat (3), a bearing (4), a protective sleeve (6), a right five-way seat (8), an elastic body (9), a needle bearing (12) and a strain gauge (16), wherein the two ends of the protective sleeve (6) are respectively connected to the left bearing seat (3) and the right five-way seat (8), the bearing (4) is installed between the left bearing seat (3) and the middle shaft (1), the needle bearing (12) is installed between the elastic body (9) and the middle shaft (1), the elastic body (9) is located in the right five-way seat (8), the strain gauge (16) is adhered to the elastic body (9), and the two ends of the elastic body (9) are respectively a fixed end and a free end, characterized in that: The fixed end of the elastic body (9) is fixed to the right five-way seat (8), and a limiting convex rib (19) is arranged outside the free end of the elastic body (9). The limiting convex rib (19) and the elastic body (9) are arranged as an integral structure, and the limiting convex rib (19) is arranged in a C-shaped structure.

2. The center shaft torque sensor with a limit function according to claim 1, characterized in that: The central axis torque sensor further comprises a circuit board (7), a magnetic ring (15) and a waterproof signal line (17); the magnetic ring (15) is fixed on the central axis (1); the circuit board (7) is fixed on a fixed end of the elastic body (9); the magnetic ring (15) cooperates with the circuit board (7); and the circuit board (7) is connected to the waterproof signal line (17).

3. The center shaft torque sensor with a limit function according to claim 1, characterized in that: The bearing (4) is mounted on the middle shaft (1) via shaft retaining spring A (2) and shaft retaining spring B (5).

4. The center shaft torque sensor with limit function according to claim 1, characterized in that: The needle bearing (12) is mounted on the central shaft (1) via a needle bearing retaining spring (14).

5. The center shaft torque sensor with limit function according to claim 1, characterized in that: A rubber ring (10) is mounted on the central shaft (1), and the rubber ring (10) is in contact with the needle roller bearing (12).

6. The center shaft torque sensor with limit function according to claim 1, characterized in that: An adjusting nut (11) is mounted on the right five-way seat (8).

7. The center shaft torque sensor with limit function according to claim 1, characterized in that: A waterproof rubber cap (13) is installed between the right five-way seat (8) and the free end of the elastic body (9).

8. The center shaft torque sensor with limit function according to claim 1, characterized in that: A toothed disc locking nut (18) is mounted on the middle shaft (1).

9. The central axis torque sensor with a limit function according to claim 1, characterized in that: A needle roller sleeve is integrally provided in the free end of the elastic body (9), and the needle roller sleeve cooperates with the needle roller bearing (12).

10. The central axis torque sensor with a limit function according to claim 1, characterized in that: A wiring hole for leading out the waterproof signal line (17) is provided inside the elastic body (9).

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