Torque measurement system for bicycles with electric assist and bicycles with electric assist

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a torque sensor system, and in particular to a pedelec and its torque sensor system.

[0002] Specifically, the present invention relates to a torque sensor system for a pedelec, comprising an annular gear, a planetary gear train, a sun gear output shaft, and a signal processing unit which are engaged in turn; wherein: the signal processing component is provided for measuring a performance of an applied force, converting measuring results thereof to an electric signal, and outputting the electric signal. The present invention also relates to a pedelec comprising such torque sensor system.BACKGROUND OF THE INVENTION

[0003] Each of documents US 5,915,493 A and US 2002 / 0173397 A1 discloses a torque sensor system and a pedelec of the respective generic type as specified above.

[0004] Document US 5,915,493 A discloses an electric power-assisted manually powered vehicle such as a bicycle, wherein, the drive unit and control are mounted as a unit to minimize external wiring and to facilitate heat transfer from the control unit to the atmosphere while protecting the control unit. Sensors for the control unit are also mounted on the outer housing and cooperate with the internal components of the outer housing to provide the necessary signals for control. This document discloses the features of the preamble of claim 1.

[0005] Document US 2002 / 0173397 A1 discloses an auxiliary-bicycle torsion sensing and large gear plate minimization apparatus, arranged in a transmission apparatus of an auxiliary-bicycle and including a sun gear, a unidirectional device, a planet gear set and a sensing device. The sun gear of planet gear set is connected to the crank axle of auxiliary-bicycle and driven directly with it. The stepping power of the crank axle is output to the large gear plate of auxiliary-bicycle through the transmission of sun gear, planet gear and unidirectional device. One side of a swing arm, used for pivotally arranging the sun gear and the planet gear, is arranged with the sensing device. When the crank axle is rotated by the stepping force of the rider, the swing arm will generate a rotation torsion, and the sensing device senses the torsion value to control the power output of the driving motor.

[0006] Document WO 2014 / 161365 A1 discloses a motor for use on an assisted bicycle, the motor comprising a hub motor body, a central shaft provided on the hub motor body, and a planetary moment sensor mounted inside the hub motor body. The planetary moment sensor comprises a sun gear mounted on the central shaft, a planetary gear set meshing with the sun gear, and a ring gear meshing with the planetary gear set, wherein one of the planetary gear set and the ring gear is defined as a power input component and the other as an a power output component. The sun gear is further provided with a limiting mechanism for limiting rotation of the sun gear within a certain angle and a moment signaling mechanism, and the moment signaling mechanism cooperating with the sun gear.

[0007] Document JP H10-1085 A discloses a torque detector capable of directly measuring driving torque generated by manpower in succession from its generation to increase to broaden the adaptability to drive control. A crankshaft and a one-way clutch for transmitting the driving torque from the crankshaft are connected to each other by means of plurally-threaded screws of a larger lead angle. When a driving torque is generated to the crankshaft by pedaling, an axial thrust force is simultaneously caused in proportion to the driving torque. A load sensor interposed between ball bearings supporting the crankshaft and a casing detects the thrust force and sends the detection signal to a torque enumeration part of a controller which is turn enumerates a torque value.

[0008] A pedelec refers to a mechatronic vehicle on the basis of ordinary small cars, and the mechatronic vehicle takes an accumulator as the auxiliary energy with installation of motor, controller, accumulator, turning handle, brake handle and other control assembly, and display instrument system. The widespread pedelec is equipped with a speed sensor; as the speed signal is collected, the faster a person treads, the more power is outputted, and thus the speed sensor is not applicable to low speed climbing, and the riding effect is poor when climbing.

[0009] The new generation sensor system is equipped with a torque sensor; however, the existing torque sensor system is equipped with a strain set or a strain gauge structure, which collects the torque data through checking the deformation of a middle shaft under treading; as the processing of the strain set is relatively complex, it is hard to meet the consistency, and the processing cost is high. Therefore, in respect of the existing torque sensor system, it is necessary to reduce the cost and increase the reliability of the torque signal.SUMMARY OF THE INVENTION

[0010] To solve the above defects of the existing technology, the present invention provides a torque sensor system for a pedelec according to claim 1 attached and a pedelec according to claim 11 attached. Preferred embodiments of the invention are specified in dependent claims.

[0011] Compared with the existing technology, the present invention has following beneficial effects. 1. The structure of the torque sensor system is more compact, and the torque transmission signal between the planetary gear train and the annular gear is stable and reliable. 2. The rocker controls the force sensing resistor or the Hall element to convert the pressure signal, thereby replacing the strain set and the strain gauge, which can reduce the production cost and increase the consistency of the signal. 3. The torque sensor system effectively solves the problem of the pedelec that the power output is dependent on the treading pressure when climbing. 4. The torque sensor system can be widely applied in different mechanical drive structures, widening its application ranges. 5. The user will have more real riding experience and will feel more comfortable when using the pedelec with the torque sensor system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will now be described by referring to the accompanying drawings that illustrate the non-restrictive embodiments of the present invention, so that other features, objects and advantages of the present invention will be evident. Fig. 1 is a front view of a torque sensor system for a pedelec according to a first preferred embodiment of the present invention. Fig. 2 is an A-A sectional view of the torque sensor system according to the first preferred embodiment of the present invention. Fig. 3 is a partial enlarged view of a pressure conversion device according to the first preferred embodiment of the present invention. Fig. 4 is a schematic diagram of the pressure conversion device according to the first preferred embodiment of the present invention. Fig. 5 is a structural sketch view of the torque sensor system according to the first preferred embodiment of the present invention. Fig. 6 is a structural sketch view of a torque sensor system with a signal processing component being a Hall element according to a second preferred embodiment of the present invention.

[0013] In figures: 1: middle shaft; 2: sun gear output shaft; 3: first bearing; 4: second bearing; 5: planetary gear train; 51: planetary gear; 52: planetary pin; 53: planetary support; 6: annular gear; 7: fixed support; 8: signal processing component; 9: pressure conversion device; 91: locating pin; 92: rocker; and 93: return spring.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0014] A further detailed description will be provided for the present invention in combination with a description of the preferred embodiments. The following preferred embodiments will help the person skilled in the art further understand the present invention, but will not limit the present invention in any form. It is noted that the person skilled in the art can fulfill several transformations and promotions on the premise of the conception of the present invention.

[0015] As shown in Figure 1 to Figure 4, according to a first preferred embodiment of the present invention, a torque sensor system for a pedelec comprises a middle shaft 1, a planetary gear train 5, a sun gear output shaft 2, an annular gear 6, a pressure conversion device 9, a signal processing component 8 and a fixed support 7. The middle shaft 1 serves as an input shaft, which is fixed with a planetary support 53 of the planetary gear train 5 through a spline structure, and the planetary gear train 5 is driven by the middle shaft 1; a relative movement exists between the planetary gear train 5 and the sun gear output shaft 2; a torque signal acting on the middle shaft 1 is converted to a pressure signal by the annular gear 6 combined with the pressure conversion device 9, and the pressure signal is converted to an electric signal and then transmitted to a controller by the signal processing component 8; and finally, a torque feedback is achieved.

[0016] A limiting structure is arranged on the fixed support 7, for restricting a displacement of the pressure conversion device 9, so that a rocker 92 can accurately return back to an original position under an action of a return spring 93. The rocker 92 shifts between a reset position and a stressing position; at the reset position, the rocker 92 is against by the limiting structure, while at the stressing position, the rocker 92 is kept away from the limiting structure, and a gap is generated between the rocker 92 and the limiting structure.

[0017] In Figure 3, a block serves as the limiting structure is located at a power output arm side of the rocker. Alternatively, the block is located at a power input arm side of the rocker, or two blocks are respectively located at the power input arm side and the power output arm side.

[0018] The middle shaft 1 and the planetary gear train 5 are fixed together; the middle shaft 1 and the sun gear output shaft 2 are assembled together through a first bearing 3 and a second bearing 4, and the middle shaft serves as a torque input shaft.

[0019] The planetary gear train 5 comprises planetary gears 51, planetary pins 52 and the planetary support 53, wherein the planetary support 53 is connected to the middle shaft 1 through the spline structure. The planetary gears 51 are linked with the planetary support 53 via the planetary pins 52; the planetary support 53 rotates along with the middle shaft 1, and the planetary gears 51 on the planetary support 53 rotate relatively to the sun gear output shaft 2.

[0020] The pressure conversion device 9 comprises a locating pin 91, the rocker 92 and the return spring 93; wherein the locating pin 91 serves as a pivot of the rocker 92; a first end and a second end of the rocker 92 are respectively matched with the annular gear 6 and the return spring 93; and an applied force of the annular gear 6, namely a first applied force, is reduced in a certain percentage based on a lever principle and then acts on the signal processing component 8.

[0021] As shown in Figure 3, the signal processing component 8 is a force sensing resistor, which directly detects a pressure and then converts the pressure signal to the electric signal. Specifically, a second applied force, namely the reduced first applied force based on the lever principle, is applied on the return spring by the second end of the rocker, then transmitted to the force sensing resistor by the return spring, and finally converted to the electric signal by the force sensing resistor.

[0022] Figure 4 is a schematic diagram of the pressure conversion device of the torque sensor system provided by the first preferred embodiment of the present invention. In Figure 4, the first end of the rocker 92 is engaged with the annular gear 6, and when the annular gear is under an action of a torque, the torque drives the first end of the rocker 92 to rotate with the locating pin 91 as the pivot; after the first applied force is reduced based on the lever principle, the second end of the rocker 92 applies the second applied force on the return spring 93, and the return spring transfers the pressure to the force sensing resistor. Preferably, the annular gear 6 has a notch, so that the first end of the rocker 92 stretches into the notch for engaging.

[0023] Figure 6 shows a second preferred embodiment of the present invention, and the person skilled in the art can consider the second preferred embodiment as a modification of the first preferred embodiment. The second preferred embodiment is different from the first preferred embodiment in that the signal processing component 8 is a Hall element; a principle of the Hall element is displacement detection; in case of a definite structure, a linear relation exists between the torque and a displacement of the rocker 92, then a displacement signal of the rocker 92 is converted to the electric signal through the Hall element, and a torque detection is thereby realized indirectly. Specifically, the second end of the rocker applies the second applied force on the return spring, so as to generate the displacement, and then the Hall element converts the displacement to the displacement signal; wherein the Hall element is arranged on the rocker and located in the middle of two isotropic magnets. When the rocker moves, the Hall element is driven to move between the magnets, and, as a consequence, an electromotive force is accordingly generated, which will be transmitted to the controller after processing, so as to realize the torque feedback. Preferably, the reset position serves as a null position of the electromotive force.

[0024] In conclusion, the present invention provides a torque sensor system with lower cost and more reliable signal and a pedelec with more real and comfortable riding experience.

[0025] The preferred embodiments of the present invention are described above. It is noted that the present invention is not limited to the embodiments, and the person skilled in the art can make various transformations and changes within the scope of claims.

Claims

1. A torque sensor system for a pedelec, comprising a middle shaft (1), an annular gear (6), a planetary gear train (5), a sun gear output shaft (2), and a signal processing component (8) which are engaged in turn; wherein: the signal processing component (8) is provided for measuring a performance of an applied force, converting measuring results thereof to an electric signal, and outputting the electric signal; characterized in that the planetary gear train (5) acts as a power input unit, and the annular gear (6) acts as a power output unit; a pressure conversion device (9) is provided for receiving a first applied force generated by the power output unit and then converting the first applied force to a second applied force based on a lever principle; the pressure conversion device (9) is engaged in turn with the annular gear (6), the planetary gear train (5), the sun gear output shaft (2), and the signal processing component (8); and the signal processing component (8) is provided for measuring a performance of the second applied force, wherein the middle shaft (1) serves as an input shaft, which is fixed with a planetary support (53) of the planetary gear train (5) through a spline structure, and the planetary gear train (5) is driven by the middle shaft (1); a relative movement exists between the planetary gear train (5) and the sun gear output shaft (2); a torque signal acting on the middle shaft (1) is converted to a pressure signal by the annular gear (6) combined with the pressure conversion device (9), and the pressure signal is converted to an electric signal and then transmitted to a controller by the signal processing component (8); and finally, a torque feedback is achieved.

2. The torque sensor system for the pedelec as recited in claim 1, wherein the pressure conversion device (9) comprises a rocker (92), a return spring (93) and a locating pin (91); the locating pin (91) serves as a pivot of the rocker (92); a first end of the rocker (92) is matched with the power output unit, and a second end of the rocker (92) is matched with the return spring (93).

3. The torque sensor system for the pedelec as recited in claim 2, wherein the pressure conversion device (9) further comprises a limiting structure which is set at a steering direction of the rocker (92) driven by the return spring (93), for limiting a displacement of the rocker (92).

4. The torque sensor system for the pedelec as recited in claim 2, wherein the first end of the rocker (92) is engaged with the power output unit; the first applied force of the power output unit acts on the first end of the rocker (92) under a torque, and then the rocker (92) transmits the torque to the second end of the rocker (92) with the locating pin (91) as the pivot.

5. The torque sensor system for the pedelec, as recited in claim 2, wherein the first applied force is reduced to the second applied force by the rocker (92) based on the lever principle, and then the second applied force acts on the return spring (93).

6. The torque sensor system for the pedelec as recited in claim 2, wherein: the signal processing component (8) is a force sensing resistor; and the second applied force is applied on the return spring (93) by the second end of the rocker (92), then the return spring (93) transmits the second applied force to the force sensing resistor, and finally the force sensing resistor converts the second applied force to the electric signal.

7. The torque sensor system for the pedelec as recited in claim 2, wherein: the signal processing component (8) is a Hall element; and the second applied force is applied on the return spring (93) by the second end of the rocker (92), so as to generate a displacement, and then the Hall element converts the displacement to a displacement signal; wherein the Hall element is arranged on the rocker (92) and in the middle of two isotropic magnets.

8. The torque sensor system for the pedelec as recited in claim 6 or claim 7, wherein the annular gear (6) is driven by the planetary gear train (5).

9. The torque sensor system for the pedelec, as recited in claim 6 or claim 7, wherein the torque sensor system further comprises a fixed support (7) for holding the annular gear (6), the planetary gear train (5) and the signal processing component (8); and the first end of the rocker (92) is matched with an edge of the annular gear (6).

10. The torque sensor system for the pedelec as recited in claim 6 or claim 7, wherein the annular gear (6) acts as the power input unit, and the planetary gear train (5) acts as the power output unit; and the first end of the rocker (92) is matched with an edge of a planetary support (53) of the planetary gear train (5).

11. A pedelec comprising a torque sensor system as recited in any one of claims 1 to 10.