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EP-3992066-B1 - POWER SWITCHING STRUCTURE

EP3992066B1EP 3992066 B1EP3992066 B1EP 3992066B1EP-3992066-B1

Inventors

  • Lien, Norman
  • TIEN, CHI-CHEN
  • HSIEH, PEI-SHENG

Dates

Publication Date
20260513
Application Date
20211029

Claims (7)

  1. A power switching structure for driving a driven object, comprising: an input shaft (10), which is drivable by at least one primary power; a detection shaft sleeve (20), which is fixedly fit to the input shaft (10), the detection shaft sleeve (20) being operable to directly detect a torque value of the input shaft (10) and to issue a corresponding strain signal; an output assembly (30), which comprises a first transmission sleeve (31), a second transmission sleeve (35), and an output member (38), the first transmission sleeve (31) being rotatably sleeved on the input shaft (10), the second transmission sleeve (35) being rotatably sleeved on and spanning over outer circumferences of the input shaft (10) and the first transmission sleeve (31), at least one one-way bearing (37) being arranged between the second transmission sleeve (35) and the first transmission sleeve (31) to allow the first transmission sleeve (31) to drive, in a one-way manner, the second transmission sleeve (35) in an input direction of the primary power of the input shaft (10), an output member (38) being mounted on the second transmission sleeve (35) for driving the driven object; and an assisting power assembly (40), which comprises a power member (41) rotatably sleeved on the second transmission sleeve (35), at least one one-way bearing (42) being arranged between the power member (41) and the second transmission sleeve (35) to allow the power member (41) to drive, in a one-way manner, the second transmission sleeve (35) in a direction in which the output member (38) drives the driven object, in order to generate an assisting power that assistively drives the second transmission sleeve (35) according to the strain signal, wherein the power member (41) of the assisting power assembly (40) is provided with a radial-direction positioning member (43) at one side of the one-way bearing (42) and wherein the assisting power assembly (40) is provided with an axial-direction positioning member (44) at an opening side of the radial-direction positioning member (43) and wherein the driven object comprises a bicycle, and the input shaft (10) is a crankshaft of the bicycle, the crankshaft being operable through pedaling cranks on two ends thereof to generate the primary power for driving.
  2. The power switching structure according to claim 1, wherein one end of the first transmission sleeve (31) of the output assembly (30) is formed with a coupling section (32), and a corresponding end of the detection shaft sleeve (20) is formed with a coupling section (25) correspondingly connectable therewith, so as to allow the input shaft (10) to drive, by means of the detection shaft sleeve (20), the first transmission sleeve (31).
  3. The power switching structure according to claim 2, wherein the coupling section (25) of the detection shaft sleeve (20) comprises external mating teeth, and the coupling section (32) of the first transmission sleeve (31) comprises internal mating teeth engageable therewith.
  4. The power switching structure according to claim 1, wherein at least one bearing (36) is arranged between the second transmission sleeve (35) of the output assembly (30) and the input shaft (10).
  5. The power switching structure according to claim 1 or 2 or 4, wherein at least one bearing (33) is arranged between the first transmission sleeve (31) of the output assembly (30) and the input shaft (10).
  6. The power switching structure according to claim 1, wherein the second transmission sleeve (35) of the output assembly (30) is provided with a radial-direction positioning member (371) at two sides of the one-way bearing (37).
  7. The power switching structure according to claim 6, wherein the output assembly (30) is provided with an axial-direction positioning member (372) arranged at an opening side of the radial-direction positioning member (371).

Description

An existing bicycle torque detection mechanism is generally a strain gauge attached to a surface of a crankshaft. The crankshaft, when driven by pedaling acting on the left-side and right-side crank, would undergo deformation by torque applied thereto, so that the strain gauge may detect a strain occurring in the crankshaft, and a controller is operable to control an assisting power output from an assisting motor or to make direct driving. However, in such a structure, when pedaling is applied to a crank that is provided with a chain wheel, a portion of the force is transmitted to the chain wheel, so that the torque that is applied to the crankshaft would exhibit a great error, thereby reducing the accuracy of measurement, and thus affecting the amount of assisting power output from the motor. In other words, the known torque detection mechanism may induce an error in the measurement of the torque-induced deformation of the crankshaft and this cause an issue of incorrect supply of assisting power. Further, when it needs to do direct driving by applying an external force, the primary power and the assisting power may cause interference to thereby cause damage of parts and failure of conducting switching according to practical needs of a user. Prior art patent documents are known. WO 2019/176649 A1 discloses a motor unit used in an electric bicycle. An outputter is connected with a sprocket. The outputter has teeth to engage with a gear of the motor unit. The motor unit is arranged at one side of an input shaft 6 to supply torque to the sprocket, so that the outputter is operable to output a combined force of human power and torque from the motor unit. SUMMARY OF THE INVENTION Thus, the primary objective of the present invention is to enable selection made for supplying a primary power, an assisting power, or an external power for driving, in order to suit the needs for different types of driving. A secondary objective of the present invention is to provide a simple structure for reducing transmission loss of an acting force of an input shaft and for timely and accurately measure a torque value of the input shaft to thereby greatly reduce a measurement error of the torque value of the input shaft, making the output of an assisting power smoother and more stably, without causing situations of incorrectness or abrupt rushing, so as to make driving by the assisting power more reliable. As such, the present invention uses the detection shaft sleeve of the input shaft to indirectly drive the first and second transmission sleeves of the output assembly, and a phenomenon of micro-motion static frictional force is induced between the first and second transmission sleeves and the input shaft, allowing the detection shaft sleeve to directly and accurately measure a torque value of the input shaft, so as to avoid the situation that a small force cannot be effectively detected, while a large force as a result of accumulation thereof cause an abrupt rush of the assisting power, and consequently, outputting of the assisting power is made smooth and stable. Also, based on the arrangement of the one-way bearings between the second transmission sleeve and the first transmission sleeve and the power member, the output member of the second transmission sleeve may select a source of power according to practical needs to thereby enhance flexibility of operation thereof. The present invention provides a power switching structure for driving a driven object, which comprises: an input shaft, which is drivable by at least one primary power; a detection shaft sleeve, which is fixedly fit to the input shaft, the detection shaft sleeve being operable to directly detect a torque value of the input shaft and to issue a corresponding strain signal; an output assembly, which comprises a first transmission sleeve, a second transmission sleeve, and an output member, the first transmission sleeve being rotatably sleeved on the input shaft, the second transmission sleeve being rotatably sleeved on and spanning over outer circumferences of the input shaft and the first transmission sleeve, at least one one-way bearing being arranged between the second transmission sleeve and the first transmission sleeve to allow the first transmission sleeve to drive, in a one-way manner, the second transmission sleeve in an input direction of the primary power of the input shaft, the output member being mounted on the second transmission sleeve for driving the driven object; and an assisting power assembly, which comprises a power member rotatably sleeved on the second transmission sleeve, at least one one-way bearing being arranged between the power member and the second transmission sleeve to allow the power member to drive, in a one-way manner, the second transmission sleeve in a direction in which the output member drives the driven object, in order to generate an assisting power that assistively drives the second transmission sleeve according to the strai