TWI564214B - Bicycle torque sensing device - Google Patents

Description

Bicycle torque sensing device

The present invention relates to a structural technique for sensing the torque of a bicycle by sensing strain, and more particularly to a torque sensing device for a bicycle.

As we all know, a bicycle is not only a kind of vehicle, but also a kind of leisure sports equipment. Its action is mainly by stepping on the foot of the rider, driving the chain through the crankshaft to drive the chain, thereby driving the wheel to rotate as a bicycle. Power, however, the road conditions encountered by riders when riding bicycles are not fixed, sometimes flat terrain, sometimes sloped terrain, especially sloped terrain, which will consume a lot of riders. Physical strength, in order to solve this problem, the development of electric bicycles.

The known electric bicycle is mainly driven by a motor to provide power. The power of the motor and the rider's pedaling force are integrated to drive the bicycle forward, so as to save the rider's physical strength. In the specific implementation, the way to control the output power of the motor can be divided into two types, one of which is a simple manual switch control, which enables the rider to provide power by manually turning on the motor, thereby reducing the output of the rider. The other is to measure the torque generated by the rider's pedaling force by the torque sensing device, and to control the output power of the electric motor by the magnitude of the torque.

For example, Taiwan Patent Publication No. M451316 and Taiwan Patent Publication No. M417320 respectively disclose that a sleeve is disposed on a crank shaft, and a surface of the sleeve is attached with a strain gauge for measuring a sleeve generated by a torsion force. Dependent variable, and convert the measured strain variable into a strain signal to control The electric motor outputs power.

However, the above-mentioned prior art adopts the method of fixing the strain gauge on the surface of the sleeve and the sleeve sleeved on the crank shaft. When the crank shaft is deformed by the torsion force, it is easy to occur because the deformation amount is small and is not easily transmitted to the sleeve. The phenomenon of the cylinder, which in turn causes the accuracy of the strain gauge to sense the torque, and the position of the mounting strain gauge of the above-mentioned prior art is a sleeve sleeved on the crankshaft, the sleeve is a rotating component, The signal output must be swiped by a slip ring or using wireless transmission technology, and these methods are easy to generate additional noise resulting in poor accuracy.

In view of this, the present invention aims to improve the structural position of the strain gauge in the torque sensing device of the conventional bicycle, so that the torsion force can be fully converted into tensile stress or/and compressive stress to remove the strain gauge to avoid torque conversion. The resultant force or component form of the non-positive force causes the unnecessary deformation of the strain gauge to improve the accuracy of the strain gauge sensing torque, and the strain gauge is mounted on the wheel base, which is a fixed part. The direct connection wire transmits the signal to the processor.

In order to achieve the above object and solve the problem, a preferred technical solution of the present invention provides a torque sensing device for a bicycle, comprising: a wheel seat fixed to a side of a five-way pipe, wherein a linear shape is formed on the wheel seat The beam has a beam core extending along the extension beam, the wheel seat is fixed with a sun gear; a crank shaft is inserted through the five-way pipe, the wheel seat and the sun wheel, and the crank shaft is coupled to the plurality of shafts a planetary gear, the planetary gear and the sun gear mesh with each other; a toothed disk pivotally disposed on the crank shaft, wherein the toothed disk forms a ring gear meshing with the planetary gear; a strain gauge fixed to the beam core line a traverse beam that passes through; wherein, the planetary gear and the sun gear and the ring gear respectively form a line force, and a tangential force formed between the planetary gear and the sun gear acts as a load of the sun gear via the wheel The seat is conducted to the extension beam, and the load is converted into an axial force along the beam line via the extension beam, and the extension beam is subjected to the axial force to generate a strain, and the strain gauge senses the strain as a crankshaft Tooth The torque sensing value between the discs.

In a further implementation, the foregoing technical solution further includes: the tangential force includes a first tangential force and a second tangential force, and the first tangential force is formed between the planetary gear and the sun gear. The second tangential force is formed between the planetary gear and the ring gear, and the first tangential force is the same as the direction of the second tangential force. The sum of the first tangential force and the second tangential force generates a reaction force that is opposite to the direction of the first tangential force and the second tangential force.

The sun gear is fixed to the wheel base via at least two fixing ends, and the fixing tips are symmetrically disposed on both sides of the wheel core of the sun gear. Wherein the fixed tip is fixed on the beam center line of the wheel base. The centers of the crankshaft, the sun gear, the fixed tip and the toothed disc are all located on the same straight line, and the straight line and the beam core line form a right angle with each other.

The number of beams is symmetrically placed on the wheel base by the fixed tip spacing. The extension beam is divided into a first extension beam and a second extension beam on a common beam line, and the strain gauge is disposed on a beam center line of at least one of the plurality of extension beams, the axial direction The tensile force of the first tensile beam generates tensile strain, and the axial force compresses the second tensile beam to generate a compressive strain, and the strain gauge senses at least one of the tensile strain and the compressive strain. Generate strain.

According to the above technical solution, the technical effect of the present invention is that the torque transmitted between the crankshaft and the toothed disc via the sun gear can fully transmit the load to the tensile or/and compressive axial force to act on the beam. The tensile or/and compressive stress of each unit area of the beam with the strain gauge attached is the same, and then produces a homogeneous strain within a specific length of the beam, so that the strain gauge is homogeneous. Deformation eliminates the need for the beam to withstand unnecessary bending moment loads, thereby improving the accuracy of the strain gauge sensing torque.

In addition, since the sun gear is fixed to the wheel base, the load of the sun gear can be transmitted to the beam through the stress dispersion of the wheel seat, so that The extension beam does not generate the component force in other directions when the axial force in the direction of the core of the beam is transmitted, and the extension beam is relieved from the unnecessary bending moment load to improve the accuracy of the strain gauge sensing torque, and the contribution is provided.

The specific implementation details of the above-mentioned device and the specific implementation details thereof will be described with reference to the following embodiments and drawings.

10‧‧‧ wheel seat

11‧‧‧ seat ring

12a, 12b‧‧

13‧‧‧

13a‧‧‧The first beam

13b‧‧‧Second

13c‧‧‧The third beam

13d‧‧‧Fourth

14a, 14b‧‧ ‧ beam heart line

20‧‧‧Sun Gear

21a, 21b‧‧‧ fixed tip

30‧‧‧ crankshaft

31‧‧‧ planet carrier

32‧‧‧ planetary gear

33‧‧‧ fixed plate

34‧‧‧ screw seat

35‧‧‧ screws

36‧‧‧Sleeve

37‧‧‧ crank

38‧‧‧ pedal

40‧‧‧ toothed disc

41‧‧‧ring gear

50‧‧‧Strain gauge

51a, 51b‧‧‧ feet

52‧‧‧Sensing Department

60‧‧‧5-way pipe

61‧‧‧ screws

71, 72, 73‧‧‧ bridge

71a, 72a, 73a‧‧ ‧ instrumentation amplifier

71b, 72b, 73b‧‧‧ rectifier

71c, 72c, 73c‧‧‧ numerical control unit

74‧‧‧Voltage and Torque Converter Module

L‧‧‧ Straight line

1 is a perspective exploded view of the first embodiment of the torque sensing device of the present invention; FIG. 2 is a cross-sectional view of the combination of FIG. 1; FIG. 3 is a cross-sectional view of the AA of FIG. Figure 2 is a cross-sectional view taken along line BB; Figure 5 is an explanatory view of the axial force acting on the beam in Figure 4; Figure 6 is a schematic view of the strain gauge in Figure 3 subjected to axial force; Figure 7a and Figure 7b are respectively 3 is a partially enlarged cross-sectional view of the girders of FIG. 3 and a schematic cross-sectional view thereof; FIG. 8a to FIG. 8c are schematic diagrams showing the circuit arrangement of the strain gauges shown in FIG. 3 in different carrying quantities; FIG. 9 is the first embodiment of the present invention. Control flow chart of the second embodiment.

First, referring to FIG. 1 to FIG. 4, a first embodiment of a torque sensing device for a bicycle provided by the present invention is disclosed. The torque sensing device includes a wheel base 10, a crank shaft 30, and a tooth. The disk 40 and a strain gauge 50. The wheel base 10 is screwed to the side of the Bottom Bracket Shells 60 by screws 61. A circular seat ring 11 is formed around the wheel base 10, and the center sides of the wheel base 10 are respectively formed. a circular trough 12a, 12b, the wheel base 10 is formed between the circular seat ring 11 and the two circular volutes 12a, 12b In the embodiment, the extension beam 13 is integrally formed with the circular seat ring 11 and the two circular volutes 12a, 12b. The extension beam 13 includes a first extension beam 13a, a second extension beam 13b, a third extension beam 13c and a fourth extension beam 13d, wherein the first extension beam 13a and the second extension beam 13b are the same beam core line 14a Throughout and evenly, the third extension beam 13c and the fourth extension beam 13d are penetrated and evenly divided by the other beam core line 14b, and the beam core lines 14a and 14b are spaced apart from each other and symmetrically distributed with respect to the wheel base 10. The strain gauge 50 is fixed to the first extension beam 13a, the second extension beam 13b, the third extension beam 13c, and the fourth extension beam 13d, respectively.

A sun gear 20 is fixed to the wheel base 10, and the wheel base 10 is disposed in the same axial direction as the sun gear 20, and the sun gear 20 is fixedly fixed to the wheel base 10 through the two fixing ends 21a and 21b, respectively. More specifically, the two fixed tips 21a, 21b are symmetrically disposed on both sides of the wheel center of the sun gear 20, so that the sun gear 20 can be fixed to the two circular volutes 12a, 12b through the two fixed tips 21a, 21b, respectively. It is integrated with the wheel base 10. The center of the fixed tip 21a is located on the circular volute 12a between the first extension beam 13a and the second extension beam 13b, and the first extension beam 13a, the center of the fixed tip 21a and the second extension beam 13b are sequentially The same beam core line 14a is penetrated, and the center of the fixed tip 21b is located on the circular trough 12b between the third extension beam 13c and the fourth extension beam 13d, and the center of the third extension beam 13c and the fixed tip 21b And the fourth girders 13d are sequentially penetrated by the same beam core line 14b, and the centers of the fixed tips 21a, 21b are respectively connected to the center of the collinear strain gauge 50 via the beam core lines 14a and 14b, respectively. And separated from each other.

The crankshaft 30 extends through the five-way pipe 60. The crankshaft 30 is fixedly connected with a crank 37 at both ends thereof, and a pedal 38 is pivotally connected through the crank 37. The crankshaft 38 can be used to drive the crank through the pedal of the rider. The shaft 30 rotates. A crank-shaped carrier 31 is axially coupled to the crankshaft 30. The carrier 31 is pivotally provided with a plurality of planetary gears 32. The planetary gears 32 are symmetrically disposed on the planet centering on the crankshaft 30. The frame 31 is placed in engagement with the sun gear 20 described above.

In addition, the crankshaft 30 is further provided with an annular fixing plate 33. The fixing plate 33 is provided with a screw seat 34, so that the carrier 31 can be screwed into the screw seat 34 by the screw 35 and the fixing plate 33. In combination, the planetary gear 32 is pivotally disposed between the carrier 31 and the fixed plate 33. The screw seat 34 is further sleeved with a sleeve 36. When the carrier 31 and the fixed plate 33 are integrally formed, The sleeve 36 is seated between the planet carrier 31 and the fixed plate 33 for maintaining a fixed distance between the carrier 31 and the fixed plate 33 to avoid the relationship between the carrier 31 and the fixed plate 33. The spacing is too small to cause the planet gears 32 to be obstructed while rotating.

The toothed disc 40 is pivotally mounted on the crankshaft 30. The ring gear 40 is formed with a ring gear 41 that meshes with the planetary gear 32. In a specific implementation, the toothed disc 40 is disposed on the carrier 31 and the fixed plate 33. The ring gear 41 is meshed with the planetary gear 32 therebetween.

Referring to FIG. 4 and FIG. 5, the crankshaft 30, the sun gear 20 and its fixed tips 21a, 21b, and the ring gear 40 and its ring gear 41 are illustrated. The centers of the components are all disposed on the same straight line L. The straight line L is parallel to the Y axis in the drawing, and the perpendicular line L and the beam line 14a, 14b form a right angle with each other.

Therefore, the crankshaft 30 contacts the ring gear 41 and the sun gear 20 via the planetary gears 32, respectively. When the planetary gears 32 rotate around the sun gear 20 in the clockwise direction, the planetary gears 32 themselves rotate in a clockwise direction. The planetary gear 32 drives the ring gear 41 to rotate in a clockwise direction to output power. When the ring gear 41 generates the torsion load T2, the planetary gear 32 generates the torsion T1 and the torsion load T3 on the sun gear 20, and the balance of the force is known to be T1=T2+T3. Wherein, the line force F1 is formed at the point of contact between the planetary gear 32 and the sun gear 20, and the line force F2 is formed at the point of contact between the planet gear 32 and the ring gear 41, and the tangential force F1 and F2 is parallel to each other.

When the planetary gear 32 is rotated by the crankshaft 30, the wheel core of the planetary gear 32 forms a reaction force F, and the center of the planetary gear 32 from the center of the crankshaft 30 is R1, so that T1 is known. =6×(F×R1), and according to the force balance theorem Σ F _x =0, it can be seen that F=F1+F2, through the calculation formula of the above-mentioned torque, it is known that T2=6×(F2×R2) (ring gear 41) The pitch circle radius), T3 = 6 × (F1 × R3) (the pitch circle radius of the sun gear 20).

Referring to FIG. 5 and FIG. 6 together, the tangential force F1 received by the sun gear 20 is transmitted to the wheel base 10 through the fixed tips 21a and 21b, and then transmitted to the beam 13 through the wheel base 10, from the above T3=6. ×(F1×R3), it can be seen that: 6 × (F1 × R3) = (F _{strain A} + F _{strain B} ) × R _strain , and F _{strain A} = F _{strain B} , F _{strain A} = F _{strain A1} + F _{strain A2} , F _{strain B} = F _{strain B1} + F _{strain B2} .

Where F _{strain A} is the sum of the axial forces received by the extension beams 13a, 13b, respectively, F _{strain A1} is the axial force received by the extension beam 13a, and F _{strain A2} is the axial direction of the extension beam 13b. The force, F _{strain B} is the sum of the axial forces respectively received by the extension beams 13c, 13d, the F _{strain B1} is the axial force received by the extension beam 13c, and the F _{strain B2} is the axis to which the extension beam 13d is subjected. The force, R _strain, is the distance between the center of the sun gear 20 to the center of the fixed tip 21a or 21b. According to this, the value of the axial force F _strain respectively received by the extension beam 13 can be obtained, and the strain generated by the extension beam 13 can be known.

Further, as shown in Figure 6, the first derivative beam and a second derivative beam 13a 13b, the axial force F _{strain A1} beam on the center line 14a of the X-axis direction to provide the forward biasing force F _compress the compression effect The first _tensile beam 13a and the strain gauge 50 fixed on the beam generate a compressive strain, and the axial force F _{strain A2} acts on the second _tensile beam 13b and the strain fixed on the beam by a positive tensile force F The tensile strain of the gauge 50 is generated. In the same situation, the third beam 13c and the strain gauge 50 fixed on the beam are also subjected to the tensile force F _tensile of the axial force F _{strain B1} in the X-axis to generate tensile strain, the fourth The extension beam 13d and the strain gauge 50 fixed on the beam are also subjected to a compressive strain by the action of the forward compression force F _compress of the axial force F _{strain B2} in the X-axis direction.

Referring to FIG. 3, it can be seen that the strain gauge 50 of the present invention must be fixed on the beam 13 through which the beam core wires 14a, 14b pass; basically, when In the case where any of the fracture gauges 50 has the same fracture area, the strain generated by each of the fractured regions should be the same, so the strain gauge 50 is only parallel to the beam cores 14a, 14b and fixed. On the Yanliang beam 13, a simple tensile strain or/and a compressive strain can be sensed. In other words, the fixed position of the strain gauge 50 on the beam cores 14a, 14b of the beam 13 is slightly upward or downward. It should not affect the accuracy of its sensed strain. In the implementation in which the above-mentioned extension beam 13 is divided into the first extension beam 13a, the second extension beam 13b, the third extension beam 13c, and the fourth extension beam 13d, the strain gauge 50 is fixed to the beam through which the beam core line 14a passes. The first beam 13a and the second beam 13b are arranged such that the center of the fixed tip 21a and the center of the strain gauge 50 are spaced apart from each other via the beam core line 14a, and the strain gauge 50 is fixed to the beam core line 14b. The third extension beam 13c and the fourth extension beam 13d are spaced apart from each other by the center of the fixed tip 21b and the center of the strain gauge 50 via the beam core line 14b. The fixing comprises integrally bonding the strain gauge 50 with the first extension beam 13a, the second extension beam 13b, the third extension beam 13c and the fourth extension beam 13d by means of adhesive bonding or embedding.

In addition, as can be further seen from FIG. 7a, the center of the strain gauge 50 is spaced apart from each other via the beam core lines 14a, 14b, meaning that the strain gauge 50 has two pins 51a, 51b which are substantially parallel to each other, and two pins. 51a, 51b are connected to form a plurality of serpentine-shaped sensing portions 52. When fixed, the two pins 51a, 51b are bisected on both sides of the beam wires 14a, 14b, and a plurality of snake-bend-shaped The sensing portion 52 is substantially parallel to the two sides of the beam wires 14a, 14b, and the two pins 51a, 51b are used to connect the bridge circuit (described later in detail). Accordingly, the positive compressive force F _compress can compress the strain gauges 50 on the first and second tenth beams 13a and 13d to generate a compressive strain, and the forward tensile force F _tensile can be stretched. The strain gauge 50 acting on the second extension beam 13b and the third extension beam 13c generates a tensile strain.

Please combine FIG. 7a and FIG. 7b to illustrate that the present invention is sensitive to the strain gauge generated by sensing the strain ε generated by the beam 13. In a preferred implementation, if the beam 13 has a change in curvature or profile. When different sections have different cross-sectional areas, the fixed strain gauge 50 at the minimum cross-sectional area A of the extension beam 13 may be selected to be optimal, and the minimum cross-sectional area A must be maintained on the extension beam 13 to be sufficient for overlaying. Or fixing the appropriate length of the strain gauge 50 such that any minimum cross-sectional area A within the appropriate length range is the same, so that the load that the sun gear 20 can bear can be agilely transmitted to the girders 13 via the volutes 12a, 12b. The strain is generated by the minimum cross-sectional area A of the gauge 50; however, the present invention is not limited thereto, and the strain gauge 50 can be sensed as long as the strain gauge 50 is fixed to the beam 13 through which the beam wires 14a, 14b pass. The strain. Further, the stress σ of each of the mass points P in the cross-sectional area A of the fixed strain gauge 50 on the extension beam 13 must be within the fatigue strength of the metal material selected for the extension beam 13. The above stress σ and strain ε are expressed by the following formulas (1) and (2):

Where S _ult is the tensile strength, E is the Young's modulus of the metal material of the _Yanliang 13, ε is the strain generated by the _Yanliang 13, and δ is the elongation or reduction of the tensile beam 13 after being applied by the axial force F. L is the length before the beam 13 is unstressed.

Next, please refer to FIG. 8a to FIG. 8c in combination, wherein FIG. 8a reveals that when the number of the extension beams 13 is singular or majority, only one strain gauge 50 is fixed on one of the extension beams 13, and the strain is connected by using the bridge 71. The pins 51a, 51b of the gauge 50 further detect the amount of change when the strain gauge 50 is affected by the strain ε generated on the beam, wherein the bridge 71 has the following formula (3): Where V _in is the input voltage of the power supply terminal, V _ab is the voltage difference between the point a voltage V _a and the point b voltage V _b , R ₄ is the resistance value of the strain gauge 50, and R ₁ , R ₂ , and R ₃ are respectively The resistance of the dissimilar resistance, and let R ₁ = R ₂ = R ₃ = R , when the strain gauge 50 is subjected to the positive compressive force F _compress or the positive tensile force F _tensile , R ₄ will be generated. The change includes that the resistance value of the strain gauge 50 becomes smaller when it is pressed, and the resistance value becomes larger when it is pulled. Accordingly, by bringing R ₄ = R + Δ R into the formula (3), the following formula (4) can be obtained: Where Δ R is the amount of change in which the resistance value becomes smaller or larger. Since the amount of change of Δ R is very small, the value of V _ab is also small, and the value needs to be amplified by the instrumentation amplifier 71a. The magnification of the instrumentation amplifier 71a is G , so the output voltage is calculated according to the following equation (5). :

Above output voltage After being rectified by the rectifier 71b, it is supplied to a numerical control unit (MCU) 71c to be based on the output voltage. The change value is used as the strain generated by the axial beam force of the above-mentioned extension beam 13, and is converted into a precise torque sensing value between the crankshaft 30 and the toothed disc 40.

Figure 7b shows the configuration of a bridge 72 with strain gauges 50 (i.e., two strain gauges) attached to the two beams 13a and 13b or 13c and 13d, respectively, and wherein R ₁ = R ₃ = R When the strain gauge 50 is subjected to the above-mentioned positive compressive force F _compress or tensile force F _tensile , the resistance values R ₂ and R _{4 of the} two strain gauges 50 change, and the resistances R ₂ and R _{4 of the} two strain gauges are When the force is changed, the resistance changes are -Δ R and Δ R , respectively. Therefore, the resistance values are R ₂ = R - Δ R and R ₄ = R + Δ R and are brought into the equation (3) to obtain the following formula (6). ):

After amplifying G times by the instrumentation amplifier 72a, the output voltage can be calculated according to the following formula (7). : The functions of the instrumentation amplifier 72a, the rectifier 72b and the numerical control unit (MCU) 72c are the same as described above.

Comparing equations (5) and (7), it can be seen that using two strain gauges 50 can obtain a larger output voltage variation than using one strain gauge 50. ,that is < And the use of two strain gauges 50 is about twice as large as the voltage change using a strain gauge 50. Since the denominator is constant, the linearity of using two strain gauges 50 is better than the design using one strain gauge 50. better.

FIG. 8c discloses a bridge circuit required to be assembled on the bridges 73 of the four beams 13a, 13b, 13c, and 13d, respectively, when a strain gauge 50 is fixed (ie, four strain gauges), when the strain gauge 50 is contracted or When the tension is stretched, the resistance values R ₁ , R ₂ , R ₃ and R ₄ change. When the resistances R ₂ and R ₃ are under stress, the resistance changes by -Δ R and the resistors R ₁ and R ₄ are stressed. The amount of change in the resistance value is Δ R , so that the resistance value is R ₂ = R ₃ = R - Δ R and R ₁ = R ₄ = R + Δ R and brought into the above formula (3), the following formula can be obtained ( 8): The output voltage of the following formula (9) can be calculated by amplifying G times by the instrumentation amplifier 73a. : The functions of the instrumentation amplifier 73a, the rectifier 73b, and the numerical control unit (MCU) 73c are the same as described above.

Comparing equations (7) and (9), it can be seen that using four strain gauges 50 can achieve a larger output voltage variation than using two strain gauges 50. ,that is < And it is known that the four-piece strain gauge 50 is twice the amount of change of the two strain gauges 50, and is about four times the amount of change of one strain gauge 50. Therefore, in the present invention, the more the number of the strain gauges 50 are arranged, the more accurate the torque sensing values that can be converted. However, the number of the configuration of the strain gauge 50 is not limited to four pieces, in other words, the application of the above formulas (5) and (7) is also applicable to the embodiment having four girders 13 .

Please refer to the control flow chart disclosed in FIG. 9 to illustrate that the output voltage can be rectified according to the rectifiers 71b, 72b, and 73b in FIGS. 8a, 8b, and 8c. , , For the function, a voltage value | V ₀ | representing the torque of the current output of the crankshaft 30 is obtained, and the voltage value | V ₀ | is transmitted to the numerical control unit (MCU) 71c, 72c, 73c to calculate the crankshaft. 30 output torque value. The voltage control unit (MCU) 71c, 72c, 73c carries a voltage and torque conversion module 74, and the voltage value | V ₀ | is transmitted to the voltage and torque conversion module 74, and the voltage value | V ₀ | Converted into a torque value | T ₀ |, and the numerical control unit (MCU) 71c, 72c, 73c or the voltage and torque conversion module 74 is built in or can be externally set to a predetermined torque value | |. When the torque value | T ₀ | is greater than the predetermined torque value | |hours (ie | T ₀ |>| |), the motor is provided with auxiliary power, and the auxiliary power is adjusted according to the change of the torque value. Conversely, when the torque value | T ₀ | is less than the predetermined torque value | |hours (ie | T ₀ |<| |), the motor is stopped to provide auxiliary power.

According to the description of the above embodiments, it should be understood that the present invention relies on the load of the sun gear to withstand the torsion between the crankshaft and the toothed disc, so that the load can be agilely transmitted to the beam of the fixed strain gauge. Effectively preventing the truss beam from being subjected to unnecessary bending moment load, thereby generating a uniform strain in a specific length range of the girders, so that the strain gauge generates a homogeneous deformation, thereby indeed improving the strain gauge in the torsion device. Torque sensing accuracy.

However, it should be noted that the above embodiments are merely illustrative of preferred embodiments of the invention, and are not to be construed as limiting the scope of the invention. Therefore, the present invention should be based on the content of the claims defined in the scope of the patent application.

10‧‧‧ wheel seat

12a, 12b‧‧

20‧‧‧Sun Gear

21a, 21b‧‧‧ fixed tip

30‧‧‧ crankshaft

31‧‧‧ planet carrier

32‧‧‧ planetary gear

33‧‧‧ fixed plate

37‧‧‧ crank

40‧‧‧ toothed disc

41‧‧‧ring gear

60‧‧‧5-way pipe

Claims (8)

A torque sensing device for a bicycle, comprising: a wheel seat fixed on a side of a five-way pipe, wherein the wheel seat is formed with a linear beam, the beam having a beam line extending along the beam, the wheel seat a sun gear is fixedly attached; a crank shaft extends through the five-way pipe, the wheel base and the sun gear, the crank shaft is coupled to the plurality of planetary gears, the planetary gear and the sun gear mesh with each other; Provided on the crankshaft, a ring gear meshing with the planetary gear is formed in the toothed disc; a strain gauge is fixed on the extension beam through which the beam core extends; wherein the planetary gear and the sun gear A line force is formed between the ring gears, and a tangential force formed between the planetary gear and the sun gear is transmitted as a load of the sun gear to the extension beam via the wheel seat, and the load is converted into a beam along the beam by the extension beam. The axial force of the core wire is subjected to the axial force to generate a strain, and the strain gauge senses the strain as a torque sensing value between the crankshaft and the toothed disc. The torque sensing device for a bicycle according to claim 1, wherein the tangential force includes a first tangential force and a second tangential force, and the first tangential force is formed on the planetary gear. The second tangential force is formed between the planetary gear and the ring gear, and the first tangential force is the same as the direction of the second tangential force. The torque sensing device for a bicycle according to claim 2, wherein the sum of the first tangential force and the second tangential force generates a reaction force, the reaction force and the first tangential force and the The direction of the second tangential force is opposite. The torque sensing device for a bicycle according to claim 1, wherein the sun gear is fixed to the wheel base via at least two fixing ends, the fixing The tip is symmetrically disposed on both sides of the wheel of the sun gear. The torque sensing device for a bicycle according to claim 4, wherein the fixed tip is fixed to a beam center line of the wheel base. The torque sensing device for a bicycle according to claim 5, wherein the centers of the crankshaft, the sun gear, the fixed tip and the toothed disc are all on the same straight line, and the straight line and the beam core line form a right angle with each other. The torque sensing device for a bicycle according to claim 4, wherein the number of the girders is symmetrically disposed on the wheel base by the fixed tip spacing. The torque sensing device for a bicycle according to the seventh aspect of the invention, wherein the beam is divided into a first beam and a second beam on a common beam line, and the strain gauge is disposed on the plurality of The axial force of the at least one of the girders of the beam, the axial force is tensilely applied to the first tempering beam to generate a tensile strain, and the axial force compresses the second tempering beam to generate a compressive strain, the strain The gauge senses at least one of the tensile strain and the compressive strain to generate a strain.