JP2015010870A - Torque sensor positioning structure and electric power assisted bicycle provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque sensor positioning structure equipped with a torque sensor support member of simple structure having excellent slidability against a detection shaft and capable of improving the detection accuracy of a torque sensor, and an electric power assisted bicycle equipped with the same.SOLUTION: Provided is a torque sensor positioning structure having a magnetostriction shaft 3 fixed at one end of a crank shaft 2, capable of rotating integrally with the crank shaft 2, and disposed coaxially with the crank shaft 2 and a torque sensor 4 for detecting torque acting on the magnetostriction shaft 3 and disposed on the outer circumferential surface of the magnetostriction shaft 3, wherein the torque sensor 4 is held by a plurality of support members 8 disposed on the outside of both ends in the axial direction of the torque sensor 4.

Description

  TECHNICAL FIELD The present invention relates to a torque sensor positioning structure and an electric assist bicycle (hereinafter also referred to as “bicycle”) including the torque sensor, and more specifically, a torque sensor having a simple structure having excellent slidability with respect to a detection shaft. The present invention relates to a torque sensor positioning structure including a support member and capable of improving the detection accuracy of the torque sensor, and an electric assist bicycle including the same.

  In a bicycle using an electric motor as auxiliary power, auxiliary power is output according to the torque acting on the crankshaft, and therefore it is necessary to assemble a torque sensor for detecting the torque. As this torque sensor, a sensor that is mechanically detected by a sensor incorporated in a crankshaft portion of a bicycle and a device that detects torque by tension of a driving chain are conventionally known.

  A torque sensor of the type that detects torque with a sensor built into the crankshaft is a magnetostrictive foil that has a magnetostrictive effect wrapped around the outer peripheral surface of the magnetostrictive shaft that is fixed at one end of the crankshaft and can rotate integrally with the crankshaft. It has been fastened. In this type of magnetostrictive torque sensor, the magnetostrictive material fixed to the outer peripheral surface of the shaft is distorted by being twisted by the torque acting on the shaft, and the magnetic permeability changes, and the magnetic flux corresponding to the change in the magnetic permeability The torque is detected on the basis of the induced electromotive force induced in the detection coil by the change of. Therefore, such a torque sensor needs to be accurately positioned.

  Examples of the torque sensor positioning structure include Patent Documents 1 and 2. In Patent Document 1, an annular hollow member inserted on the outer periphery of the crankshaft and a one-way clutch provided on the hollow member for transmitting the pedaling torque to the rear wheel are provided in a recess provided on the outer periphery of the hollow member. A structure has been proposed in which a magnetic film is applied and the magnetostrictive torque sensor is positioned by a support member that is rotatably supported relative to the hollow member at both ends of the recess so that the magnetostrictive torque sensor is positioned at a position facing the magnetic film of the recess. . In Patent Document 2, a cylindrical coil bobbin around which a coil is wound is fitted on the sensor shaft so as to be relatively rotatable on the sensor shaft, and includes a cylindrical shield yoke that covers the outer peripheral side of the coil. A support body formed of a rubber-like elastic body formed on the outer peripheral side of the coil bobbin on the outer peripheral side of the coil bobbin, with a flange extending radially inward at the axial end. A structure has been proposed in which the support body supports the flange portion of the shield yoke so that a gap is formed between the support and the coil bobbin.

JP 2012-046154 A JP 2003-028736 A

  However, in the methods proposed in Patent Documents 1 and 2, the structure of the support member (support) of the torque sensor is complicated, or the slidability of the support member (support) with respect to the detection shaft of the torque sensor is not good. If it was enough, there were still problems to be solved. It is also an important issue to improve the torque detection accuracy of the torque sensor.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a torque sensor positioning structure that includes a torque sensor support member having a simple structure having excellent slidability with respect to a detection shaft and that can improve the detection accuracy of the torque sensor. Another object of the present invention is to provide an electric assist bicycle equipped with the same.

  As a result of intensive studies to solve the above problems, the present inventor can solve the above problems by arranging a predetermined support member on both sides of the torque sensor and holding the torque sensor between the support members. The present inventors have found that this can be done and have completed the present invention.

That is, the torque sensor positioning structure of the present invention is fixed on one end side of the crankshaft, is rotatable integrally with the crankshaft, and is disposed on the same axis as the crankshaft, and the magnetostrictive shaft. A torque sensor positioning structure having a torque sensor that is disposed on the outer circumferential surface of the magnetic sensor and that detects torque acting on the magnetostrictive shaft,
The torque sensor is characterized in that it is sandwiched between a plurality of support members respectively disposed on both outer sides in the axial direction of the torque sensor.

  In the torque sensor positioning structure of the present invention, among the plurality of support members disposed on both outer sides in the axial direction of the torque sensor, the outermost support member and the innermost support member in the axial direction are highly slidable. It is preferable to consist of materials. In the torque sensor positioning structure according to the present invention, the torque sensor and the plurality of support members may include a protruding ridge provided on one side of the magnetostrictive shaft and extending in the circumferential direction, and the protruding ridge sandwiching the magnetostrictive portion. It is preferable that it is clamped by the clamping member arrange | positioned on the opposite side. Furthermore, in the torque sensor positioning structure of the present invention, it is preferable that an elastic member is interposed between the clamping member and the support member on the outermost side in the axial direction on the clamping member side. Furthermore, in the torque sensor positioning structure of the present invention, it is preferable that at least one of the plurality of support members on the clamping member side of the torque sensor and the magnetostrictive shaft are made of a magnetic material.

  The electrically assisted bicycle according to the present invention is characterized by including the torque sensor positioning structure according to the present invention.

  According to the present invention, a torque sensor positioning structure that includes a torque sensor support member having a simple structure having excellent slidability with respect to a detection shaft, and that can improve the detection accuracy of the torque sensor, and An electrically assisted bicycle provided with this can be provided.

It is a schematic cross-sectional perspective view in the vehicle width direction of the hanger part of the bicycle to which the torque sensor positioning structure of the present invention is applied. It is a vehicle width direction schematic sectional drawing of the hanger part of the bicycle to which the positioning structure of the torque sensor of this invention is applied. It is a side view which shows the structure of the crankshaft to which the positioning structure of the torque sensor of this invention was applied. It is a disassembled perspective view which shows the structure of the crankshaft to which the positioning structure of the torque sensor of this invention was applied. It is sectional drawing of the torque sensor vicinity which concerns on the positioning structure of the torque sensor of this invention. It is a disassembled perspective view which shows the structure of the hanger pipe of the bicycle to which the positioning structure of the torque sensor of this invention was applied. It is a perspective view of an example of the housing which concerns on the positioning structure of the torque sensor of this invention. 1 is a schematic side view of a power-assisted bicycle according to a preferred embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional perspective view of a hanger portion of a bicycle to which the torque sensor positioning structure of the present invention is applied, and FIG. 2 is a vehicle width of a bicycle hanger portion to which the torque sensor positioning structure of the present invention is applied. FIG. 3 is a side sectional view showing a configuration of a crankshaft to which the torque sensor positioning structure of the present invention is applied, and FIG. 4 is a configuration of the crankshaft to which the torque sensor positioning structure of the present invention is applied. FIG. 5 is a sectional view of the vicinity of the torque sensor according to the positioning structure of the torque sensor of the present invention.

  The torque sensor positioning structure according to the present invention relates to a torque sensor mounted in a hanger pipe 1 as a support member, which is attached to a lower portion of a bicycle seat tube along the width direction. A magnetostrictive shaft 3 which is fixed at one end side and can rotate integrally with the crankshaft 2 and is arranged coaxially with the crankshaft 2, and a torque acting on the magnetostrictive shaft 3 arranged on the outer peripheral surface of the magnetostrictive shaft 3. And a cylindrical torque sensor 4 for detection, which are accommodated in a substantially cylindrical housing 5.

  In the example shown in FIG. 3, a fitting portion in which a plurality of splines 3 a along the axial direction of the magnetostrictive shaft 3 are formed at one end portion of the magnetostrictive shaft 3 arranged on the outer side in the radial direction of the crankshaft 2. In addition, in the center of the drive sprocket 6, a fitting hole for fitting the fitting portion of the magnetostrictive shaft 3 is provided. By fitting the fitting portion of the magnetostrictive shaft 3 into the driving sprocket 6, A drive sprocket 6 is spline-fitted to the magnetostrictive shaft 3 (see FIGS. 1 and 2). In the illustrated example, the drive sprocket 6 is illustrated as the drive-side rotating member, but in the case of a belt-driven bicycle, it is a drive pulley.

  Further, as shown in FIG. 3, a magnetostrictive foil 7 is wound around the outer periphery of the magnetostrictive shaft 3 as a magnetostrictive portion having a magnetostrictive effect, and is fixed to the surface in a direction crossing the axial direction. A plurality of slits 7a are provided. As shown in the drawing, a plurality of slits 7a are arranged substantially in parallel along the circumferential direction, and three rows are arranged in the axial direction. Right next to the three rows of slits 7a, there are provided a plurality of rows of slits 7b arranged substantially symmetrically with the three rows of slits 7a. The magnetostrictive foil 7 is made of a magnetic material having a magnetostrictive effect, such as an iron-based amorphous alloy, a nickel-based alloy, or a chromium-based alloy.

  Further, as shown in FIGS. 2 and 5, the torque sensor 4 has two recesses 4a formed at positions corresponding to the rows of the plurality of slits 7a, 7b arranged symmetrically in the left-right direction. The coil bobbin 4b around which an exciting coil as a magnetic flux generating means is wound is provided, and a yoke 4c for preventing leakage of magnetic flux is disposed on the outer periphery of the coil bobbin 4b.

  As shown in FIGS. 3 to 5, the torque sensor positioning structure of the present invention includes a plurality of support members 8 arranged on both outer sides in the axial direction of the torque sensor 4. It is sandwiched between the first support member 8a, the second support member 8b, and the third support member 8c. In the illustrated example, a convex strip 3b extending in the circumferential direction is provided on the outer periphery on one side of the magnetostrictive shaft 3, and in the circumferential direction on the outer periphery on the other side of the magnetostrictive foil 7 sandwiching the magnetostrictive foil 7. An extending recess 3c is provided, and a clamping member 9 (snap ring 9 in the illustrated example) is fitted to the recess. The ridge 3b and the snap ring 9 sandwich the torque sensor 4 and the support member 8 disposed on both outer sides in the axial direction. By appropriately designing the thickness of the support member 8, the arrangement position of the torque sensor 4 in the axial direction can be determined.

  Further, as shown in the drawing, stepped portions 4e are provided at both ends of the coil bobbin 4b of the torque sensor 4, and a supporting member that contacts the torque sensor 4 among the plurality of supporting members 8, in the illustrated example, the first supporting member 8a. The axial inner surface 8aa and the outer peripheral surface 8ab are in contact with the step portion 4e of the coil bobbin, and the inner peripheral surface 8ac is in contact with the magnetostrictive shaft 3 that is the detection shaft. Both radial positionings are possible. Further, although the torque sensor 4 is sandwiched via a plurality of support members 8, the contact surfaces of the support members 8 are slidable to prevent rotation of the torque sensor with respect to the magnetostrictive shaft 3. Can do. As will be described later, in the illustrated example, the elastic member 10 is provided between the snap ring 9 and the outermost support member on the snap ring 9 side (the third support member 8c in the illustrated example). A wave washer 10 is interposed.

  In the torque sensor positioning structure of the present invention, among the plurality of support members 8 arranged on both outer sides in the axial direction of the torque sensor 4, the outermost support member 8 in the axial direction (the support member 8 c in the illustrated example) Since the innermost support member (support member 8a in the illustrated example) is made of a highly slidable material, the above-mentioned effect can be obtained satisfactorily. In this case, as the outermost support member and the innermost support member in the axial direction, for example, polyacetal (POM), polyamide (PA), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), polybutylene terephthalate ( PBT), polyether nitrile (PEN), polyether ether ketone (PEEK), phenol formaldehyde (PF), or other resin may be used, or an oil-impregnated sintered alloy or ceramic may be used. . Preferably, it is composed of POM, PA, and PTFE, and particularly preferably is composed of POM.

  In the illustrated example, the support member 8 includes three pairs of support members 8a, 8b, and 8c. However, the torque sensor positioning structure of the present invention is not limited to this. For example, it may consist of two pairs of support members, or may consist of four or more pairs of support members. Moreover, the number of each support member arrange | positioned at the axial direction both outer sides of a torque sensor may each differ. For example, a structure in which the thickness of the support member 8b on the ridge 3b side of the three pairs of support members 8 shown in the figure is increased and 8c is omitted may be employed.

  In the torque sensor positioning structure of the present invention, among the plurality of support members 8, at least one support member on the snap ring 9 side of the torque sensor 4, for example, the second support member 8 b and the magnetostrictive shaft 3. Are preferably made of a magnetic material. With this configuration, the coil bobbin 4b is covered with the protrusion 3b integral with the magnetostrictive shaft 3, the yoke 4c, and the support member (support member 8b in the illustrated example) made of a magnetic material, and leakage of magnetic flux. And the influence of an external magnetic field can be prevented, and the detection accuracy of the torque sensor 4 can be improved. The magnetic material forming the support member 8 and the magnetostrictive shaft 3 is not particularly limited as long as it can prevent leakage of magnetic flux. For example, the same magnetic material as that forming the yoke 4c can be used. . In addition, although there is no restriction | limiting in particular about the shape of the said supporting member 8, From the viewpoint of manufacturing cost and workability | operativity of an assembly operation, the annular shape as shown in figure is preferable.

  In the torque sensor positioning structure of the present invention, as described above, the clamping member 9 (the snap ring 9 in the illustrated example) and the support member 8 on the most axially outer side on the clamping member 9 side (the third in the illustrated example). The elastic member 10 (in the illustrated example, the wave washer 10) is preferably interposed between the support member 8c). By interposing the elastic member, the coil bobbin 4b is pressed against the protrusion 3b via the support member 8 even if the axial dimension of the snap ring 9 and the width of the recess 3c are varied. The position accuracy of the coil bobbin 4b is improved, and the detection accuracy of the torque sensor can be further improved. An annular rubber member or the like may be used as the elastic member 10, but a wave washer is preferable as shown in the figure.

  The torque sensor positioning structure of the present invention is sandwiched between the torque sensor 4 and a plurality of annular support members 8 arranged on both sides in the axial direction of the torque sensor 4 (in the illustrated example, one side of the magnetostrictive shaft 3). It is only important that the support member 8 is sandwiched between the circumferentially extending protrusion 3b provided on the outer periphery of the magnet and the snap ring 9 disposed on the other side of the magnetostrictive shaft 3). Other configurations are not particularly limited.

  For example, as shown in FIGS. 1 and 2, the magnetostrictive shaft 3 is rotatably mounted via bearings 11 disposed on both sides in the axial direction inside a substantially cylindrical housing 5. A female screw portion 3e is provided on the inner peripheral surface of one end of the magnetostrictive shaft 3, and a male screw portion 2a corresponding to the female screw portion 3e is provided on the outer peripheral surface of one end of the crankshaft 2. It has been. The crankshaft 2 and the magnetostrictive shaft 3 are fixed by screwing them together, and can be structured to be integrally rotatable. Furthermore, it is preferable that a ridge 2b protruding outward in the radial direction is provided along the circumferential direction on the end side adjacent to the male screw portion 2a at one end of the crankshaft 2. With this configuration, when the crankshaft 2 and the magnetostrictive shaft 3 are screwed together, the magnetostrictive shaft 3 is positioned by tightening until one end of the magnetostrictive shaft 3 abuts against the ridge 2b provided on the crankshaft 2. Can be made easier.

  Note that an adhesive may be applied to the female screw portion 3e formed on the inner peripheral surface of one end of the magnetostrictive shaft 3 and the male screw portion 2a provided on the outer peripheral surface of the crankshaft 2. The fastening portion between 3e and the male screw portion 2a may be filled with an adhesive. Thereby, the magnetostrictive shaft 3 and the crankshaft 2 can be more firmly fixed, and the female screw portion 3e and the male screw portion 2a can be prevented or suppressed from loosening.

  In the illustrated example, the substantially central portion of the magnetostrictive shaft 3 is a large diameter portion 3d having an inner diameter larger than the outer diameter of the crankshaft 2, and the inner peripheral surface of the large diameter portion 3d of the magnetostrictive shaft 3 and the crankshaft. A space 12 is formed between the two outer peripheral surfaces. Between the inner peripheral surface of the other end opposite to the one end where the female screw portion 3e of the magnetostrictive shaft 3 is formed and the outer peripheral surface of the crankshaft 2, the sliding bearing 13 is not rattled. Is intervening. The sliding bearing 13 and the drive sprocket 6 are restricted from moving in the crankshaft direction by a retaining member 14. In the illustrated example, an elastic member 15 is interposed between the slide bearing 13 and the retaining member 14. In addition to the sliding bearing, the bearing of the crankshaft 2 may be a rolling bearing such as a ball bearing or a roller bearing.

  In the illustrated example, the retaining member 14 includes a cylindrical part and a flange part, and the sliding part 13 of the sliding bearing 13 is prevented by the cylindrical part, and the driving sprocket 6 is prevented from coming off by the flange part. In the illustrated example, the magnetostrictive shaft 3 and the retaining member 14 are fixed by screwing. 1 and 2, a female screw portion 3 f is provided on the inner peripheral surface of the magnetostrictive shaft 3, and a male screw portion 14 a is provided on the outer peripheral surface of the cylindrical portion of the retaining member 14. With this structure, the retaining member 14 can be firmly fixed to the magnetostrictive shaft 3.

  As shown in the drawing, in the torque sensor positioning structure of the present invention, it is preferable that an elastic member 15 is interposed between the retaining member 14 and a bearing (slip bearing 13 in the illustrated example). With such a structure, it is possible to prevent dust and moisture from entering the inside. As the elastic member 15, for example, an O-ring or packing made of rubber or resin can be used.

  Further, in the torque sensor positioning structure shown in FIGS. 1, 2, and 4, an external output connector portion 4d is disposed on the outer periphery of the torque sensor 4, and the connector portion 4d and the harness 16 are connected to each other. The output of the torque sensor is transmitted to the outside. In the illustrated example, the connector part 4d is attached to the coil bobbin 4b, but the arrangement position of the connector part 4d is not limited to this. In the torque sensor positioning structure of the present invention, the connector portion 4d may be formed integrally with the coil bobbin 4b, or may be formed separately and fixed by bonding, screwing, or the like. Good.

  FIG. 6 is an exploded perspective view showing a configuration of a bicycle hanger pipe to which the torque sensor positioning structure of the present invention is applied, and FIG. 7 is a perspective view of an example of a housing according to the torque sensor positioning structure of the present invention. . In the torque sensor positioning structure of the present invention, as shown in FIGS. 6 and 7, the housing 5 has a large diameter portion 5a having an inner diameter into which the torque sensor 4 having the connector portion 4d can be inserted, and a large diameter. A small-diameter portion 5b having an inner diameter smaller than that of the portion 5a. It is preferable to provide an opening 5c having a width with which the connector 4d can be engaged from the end on the large-diameter portion 5a side to the opposite end on the small-diameter portion 5b. With this structure, the crankshaft 2 is inserted from the large diameter portion 5a side of the housing 5 with the magnetostrictive shaft 3 and the torque sensor 4 attached to the crankshaft 2, and the opening 5c of the housing 5 and the torque sensor By accommodating the torque sensor 4 in the housing 5 while engaging the four connector portions 4d, the connector portion 4d can be used as a detent member for the torque sensor 4. Thereby, it is possible to better prevent the torque sensor 4 from rotating with respect to the housing 5. Since the torque sensor 4 can be accommodated in the housing 5 in a state where the torque sensor 4 and the harness 16 are connected, the assembling work can be easily performed.

  In the torque sensor positioning structure of the present invention, the connector portion 4d (see FIGS. 1 and 2) has a hollow box shape, the connector portion 4d and the harness 16 are connected inside the connector portion 4d, and The inside of the connector part 4d is preferably sealed with resin. By covering the connection portion between the connector portion 4d and the harness 16 with resin, it is possible to prevent moisture from entering the connector portion 4d and to prevent the harness 16 from being damaged due to an unexpected operation.

  Next, a method of applying the torque sensor positioning structure of the present invention to the hanger pipe 1 will be described. As shown in FIG. 6, the torque sensor positioning structure of the present invention is applied to the hanger pipe 1 by inserting the housing 5 having the torque sensor positioning structure of the present invention into the hanger pipe 1. At that time, it is preferable that a detent member 17 is interposed between one end of the hanger pipe 1 in the axial direction and the housing 5.

  In the illustrated example, one end of the hanger pipe 1 is provided with a plurality of recesses 1b that are recessed inward in the radial direction. In the illustrated example, the plurality of concave portions 1 b are provided at substantially equal intervals along the circumferential direction of one end portion of the hanger pipe 1. In the illustrated example, a large-diameter portion 5a is provided on one end side of the housing 5, and a flange portion 5d is formed at the end of the large-diameter portion 5a. The flange portion 5d is provided with a plurality of concave portions 5e that are recessed inward in the radial direction at substantially equal intervals along the circumferential direction of the flange portion 5d. The large-diameter portion 5a may be formed integrally with the main body portion of the housing 5, or may be formed as a separate body and then fixed to the main body portion by a known method such as screwing.

  The illustrated anti-rotation member 17 includes an annular body portion 17a, a plurality of first engaging portions 17b protruding from the outer periphery of the body portion 17a toward the housing 5 during assembly, and an outer periphery of the body portion 17a. A plurality of second engaging portions 17c protruding toward the opposite side of the first engaging portion 17b. In the illustrated example, two first engaging portions 17 b are provided at substantially equal intervals along the circumferential direction of the main body portion 17 a, and the first engaging portions 17 b are recessed portions 5 e of the flange portion 5 d of the housing 5. Are engaged with each other.

  The second engaging portions 17c of the rotation preventing member 17 are provided between the two first engaging portions 17b at two substantially equal intervals along the circumferential direction of the main body portion 17a. The first engagement portion 17b of the rotation preventing member 17 is engaged with the recess 5e of the housing 5, and the second engagement portion 17c of the rotation prevention member 17 is engaged with the recess 1b of the hanger pipe 1, respectively. 5 is connected so as not to rotate with respect to the hanger pipe 1.

  Furthermore, as described above, the opening 1a through which the harness 16 extending from the housing 5 is taken out is provided in the substantially central portion of the hanger pipe 1 in the axial direction. If the housing 5 is connected to the rotation preventing member 17 so as not to rotate, a space is provided between the outer peripheral surface of the housing 5 and the inner peripheral surface of the hanger pipe 1. When assembling to the pipe 1, the harness 16 extends from the housing 5 by drawing the harness 16 from the inside of the hanger pipe 1 to the outside through the opening 1 a in advance and inserting the male screw portion 5 f side of the housing 5 into the hanger pipe 1. Can be taken out through the opening 1a.

  Furthermore, in the illustrated example, a fixing member 18 is used for fixing the housing 5 and the hanger pipe 1. The fixing member 18 shown in the figure has a female screw portion 18 a that is screwed into the male screw portion 5 f of the housing 5 on the inner peripheral surface thereof. Further, an abutting portion 18 b that abuts on the inner peripheral surface of the other end of the hanger pipe 1 is formed on the outer peripheral surface of the fixing member 18. The contact portion 18b has an inclined surface whose outer diameter gradually increases as it goes outward in the axial direction of the hanger pipe 1 during assembly. In the illustrated example, a flange portion 18 c is provided on the outer side in the axial direction of the contact portion 18 b of the fixing member 18.

  Furthermore, an inclined surface 1c that gradually decreases from the other end side of the hanger pipe 1 is formed on the inner periphery of the other end of the hanger pipe 1 (see FIGS. 1 and 2). The inclination angle of the inclined surface 1c of the hanger pipe 1 with respect to the axial direction is formed in accordance with the inclination angle of the contact portion 18b of the fixing member 18 with respect to the axial direction. Thereby, the contact portion 18b of the fixing member 18 contacts the inclined surface 1c of the other end of the hanger pipe 1 in a state where the female screw portion 18a of the fixing member 18 is fastened to the male screw portion 5f of the housing 5. The axis of the housing 5 and the axis of the hanger pipe 1 can be matched. Thereby, the axial center of the crankshaft 2 and the axial center of the hanger pipe 1 can be made to correspond.

Next, the electrically assisted bicycle of the present invention will be described.
FIG. 8 is a side view of the electrically assisted bicycle according to one preferred embodiment of the present invention. A vehicle body frame 102 of the electric assist bicycle 101 shown in the figure includes a head tube 103, a down tube 104 extending obliquely downward and rearward from the head tube 103, a seat tube 105 extending obliquely upward and backward from a rear end of the down tube 104, and a seat tube. A pair of left and right chain stays 106 extending rearward from the vicinity of the lower end of 105, and a pair of left and right seat stays 107 connecting the rear ends of both chain stays 106 and the upper portion of the seat tube 105 are provided. At the lower end of the head tube 103, there is a front fork 108 that extends obliquely downward and forward, and a front wheel 109 is rotatably mounted at the lower end of the front fork 108. A handle 110 is attached to the upper end of the head pipe 103, and a saddle 111 is attached to the upper end of the seat tube 105. Further, a rear wheel 112 is rotatably attached to the rear end portion of the chain stay 106.

  The bicycle 101 of the present invention has a pedal 113 as in the case of a conventional electrically assisted bicycle, and the driving force is transmitted to the chain 114 when the driver steps the pedal 113 with his / her foot and rotates the rear wheel. 112, the rear wheel 112 is driven. In the electric assist bicycle 101 shown in the figure, the electric motor is provided in the hub 109a of the front wheel 109, and a battery 115 for supplying electric power to the electric motor is detachably attached to the rear of the seat tube 105. An electric motor for supplying auxiliary driving force to the front wheels 109 is provided inside the electric motor.

  As shown in FIG. 8, the bicycle 101 of the present invention is formed by mounting the torque sensor positioning structure of the present invention on a hanger pipe 116 that is a support member attached to the lower portion of the seat tube 105 along the width direction. Is. The bicycle 101 of the present invention is not particularly limited except that it includes the torque sensor positioning structure of the present invention described above, and any other known configuration can be adopted.

DESCRIPTION OF SYMBOLS 1 Hanger pipe 1a Opening 1b Concave 1c Inclined surface 2 Crankshaft 2a Male thread part 2b Convex strip 3 Magnetostrictive shaft 3a Spline 3b Convex strip 3c Concave strip 3d Large diameter part 3e, 3f Female thread part 4 Torque sensor 4a Concave 4c Coil bobbin 4c 4d Connector part 4e Step part 5 Housing 5a Large diameter part 5b Small diameter part 5c Opening part 5d Flange part 5e Recessed part 5f Male screw part 6 Drive sprocket (drive side rotating member)
7 Magnetostrictive foil 7a, 7b Slit 8, 8a, 8b, 8c Support member 9 Holding member (snap ring)
10 Elastic member (wave washer)
11 Bearing 12 Space 13 Sliding bearing (bearing)
DESCRIPTION OF SYMBOLS 14 Stop prevention member 14a Male thread part 15 Elastic member 16 Harness 17 Anti-rotation member 17a Main body part 17b 1st engagement part 17c 2nd engagement part 18 Fixing member 18a Female thread part 18b Contact part 18c Flange part 101 Electric assist bicycle 102 Body frame 103 Head tube 104 Down tube 105 Seat tube 106 Chain stay 107 Seat stay 108 Front fork 109 Front wheel 109a Hub 110 Handle 111 Saddle 112 Rear wheel 113 Pedal 114 Chain 115 Battery 116 Hanger pipe

Claims (6)

Fixed to one end of the crankshaft and rotatable integrally with the crankshaft. The magnetostrictive shaft is arranged coaxially with the crankshaft. The magnetostrictive shaft is arranged on the outer peripheral surface of the magnetostrictive shaft and acts on the magnetostrictive shaft. In a torque sensor positioning structure having a torque sensor for detecting torque,
The torque sensor positioning structure, wherein the torque sensor is sandwiched between a plurality of support members respectively disposed on both axial outer sides of the torque sensor.   The torque sensor according to claim 1, wherein, of the plurality of support members arranged on both outer sides in the axial direction of the torque sensor, the outermost support member and the innermost support member in the axial direction are made of a highly slidable material. Positioning structure.   The torque sensor and the plurality of support members are clamped by a circumferentially extending ridge provided on one side of the magnetostrictive shaft and a clamping member disposed on the opposite side of the ridge across the magnetostrictive portion. The torque sensor positioning structure according to claim 1, wherein the torque sensor positioning structure is provided.   The torque sensor positioning structure according to claim 3, wherein an elastic member is interposed between the clamping member and the axially outermost support member on the clamping member side.   5. The torque sensor positioning structure according to claim 3, wherein at least one of the plurality of support members includes at least one support member on a clamping member side of the torque sensor and a magnetostrictive shaft.   An electrically assisted bicycle comprising the torque sensor positioning structure according to any one of claims 1 to 5.

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