JP6061799B2 - Torque sensor rotation prevention structure and electric assist bicycle having the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a rotation prevention structure for a torque sensor and an electrically assisted bicycle (hereinafter also referred to as “bicycle”) having the same, and more specifically, a rotation prevention structure for a torque sensor that can easily fix a torque sensor to a housing. The present invention also relates to an electrically assisted 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 securely fixed to a housing that houses the torque sensor.

  Examples of the structure for fixing the torque sensor to the housing include Patent Documents 1 and 2. In Patent Document 1, a male connector portion press-fitted into a window hole formed in a yoke of a torque sensor and a female connector portion inserted through a window hole formed in a housing are locked via pins. Thus, a structure for preventing the torque sensor from rotating with respect to the housing has been proposed. Patent Document 2 proposes a structure in which an engagement portion for engaging with a housing is provided on a coil bobbin around which a coil of a torque sensor is wound to prevent the coil bobbin from being rotated.

Japanese Patent Laid-Open No. 10-339679 JP 2003-28736 A

  However, the methods proposed in Patent Documents 1 and 2 are difficult to handle because the shape of the coil bobbin becomes complicated or the connector part must be mounted after the coil bobbin is inserted into the housing. There were still problems to be solved, such as the assembly process and the assembly work becoming complicated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a torque sensor rotation prevention structure capable of easily fixing a torque sensor to a housing and an electric assist bicycle including the same.

  As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by making the structure of the connector portion of the torque sensor and the housing for housing the torque sensor predetermined. The present invention has been completed.

That is, the anti-rotation structure for a torque sensor according to the present invention is provided with a crankshaft, a magnetostrictive shaft that can rotate integrally with the crankshaft, and coaxially arranged with the crankshaft, and an outer periphery of the magnetostrictive shaft. A torque sensor for detecting torque acting on the magnetostrictive shaft, and a rotation preventing structure for the torque sensor having a structure housed in the housing,
The torque sensor has a convex portion on the outer periphery, and the housing is provided with an opening with which the convex portion can be engaged, and the convex portion is locked to the opening,
The housing has a structure housed in a hanger pipe.

In the rotation preventing structure for a torque sensor according to the present invention, the housing has a cylindrical large diameter portion and a small diameter portion, and the large diameter portion has an inner diameter into which the torque sensor having the convex portion can be inserted. And it is preferable that the said opening part is provided in the said small diameter part. Moreover, in the rotation prevention structure of the torque sensor of the present invention, the convex portion is a connector portion for external output of the torque sensor, and the opening portion is opposite to the end portion of the small diameter portion on the large diameter portion side. The connector portion has a width that allows engagement with the connector portion, and the connector portion is engaged from the large-diameter portion side of the opening portion, and the connector portion is locked to the opening portion. Is preferred. Furthermore, in the rotation prevention structure for a torque sensor according to the present invention, the connector portion has a hollow box shape, the connector portion and the harness are connected inside the connector portion, and the inside of the connector portion. Is preferably sealed with a resin.

  The electrically assisted bicycle of the present invention is characterized in that the torque sensor rotation preventing structure of the present invention is applied.

  ADVANTAGE OF THE INVENTION According to this invention, the rotation prevention structure of the torque sensor which can fix a torque sensor to a housing easily, and an electrically assisted bicycle provided with the same can be provided.

1 is a schematic cross-sectional perspective view in the vehicle width direction of a hanger portion of a bicycle to which a structure for preventing rotation of a torque sensor 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 rotation prevention structure of the torque sensor of this invention is applied. FIG. 2 is a side view of a state in which the crankshaft shown in FIG. 1 is attached to a magnetostrictive shaft. It is a perspective view of an example of the coil bobbin which concerns on the rotation prevention structure of the torque sensor of this invention. It is a perspective view of an example of the housing concerning the rotation prevention structure of the torque sensor of the present invention. It is sectional drawing of the torque sensor vicinity which concerns on the rotation prevention structure of the torque sensor which concerns on one suitable embodiment of this invention. It is a disassembled perspective view which shows the structure of the hanger pipe of the bicycle to which the rotation prevention structure of the torque sensor of this invention was applied. 1 is a 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 bicycle hanger portion to which the torque sensor rotation prevention structure of the present invention is applied, and FIG. 2 is a bicycle hanger portion to which the torque sensor rotation prevention structure of the present invention is applied. FIG. 3 is a side view of a state in which the crankshaft shown in FIG. 1 is attached to the magnetostrictive shaft, and FIG. 4 is a perspective view of an example of a coil bobbin according to the rotation prevention structure of the torque sensor of the present invention. 5 is a perspective view of an example of a housing according to the rotation prevention structure of the torque sensor of the present invention, and FIG. 6 is a torque sensor according to the rotation prevention structure of the torque sensor according to a preferred embodiment of the present invention. It is sectional drawing of the vicinity.

  The structure for preventing rotation of a torque sensor according to the present invention relates to a torque sensor mounted in a hanger pipe 1 as a support member attached along the width direction to a lower part of a seat tube of a bicycle. Is hollow, has a large diameter portion 3a having an inner diameter larger than the outer diameter of the crankshaft 2, and is arranged coaxially with the crankshaft 2. And a cylindrical torque sensor 4 for detecting torque acting on the magnetostrictive shaft 3 disposed on the outer peripheral surface of the large diameter portion 3a of the magnetostrictive shaft 3, and these are substantially cylindrical. Is housed in the housing 5.

  In the example shown in FIG. 3, one end portion of the magnetostrictive shaft 3 disposed on the outer side in the radial direction of the crankshaft 2 is provided with a fitting portion in which a spline 3 b is formed along the axial direction of the magnetostrictive shaft 3. In addition, a fitting hole for fitting the fitting portion of the magnetostrictive shaft 3 is provided in the center of the drive sprocket 6. By fitting the fitting portion of the magnetostrictive shaft 3 into the driving sprocket 6, the magnetostrictive shaft is provided. 3, the drive sprocket 6 is spline-fitted (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 having a magnetostrictive effect is wound around and secured to the large diameter portion 3a (see FIG. 1) of the magnetostrictive shaft 3, and this surface intersects with the axial direction. A plurality of slits 7a arranged in the direction to be provided 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 FIG. 2, 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, and a magnetic flux is generated in each recess 4a. A coil bobbin 4b around which an exciting coil as a generating means is wound is disposed, and a yoke 4c for preventing leakage of magnetic flux is disposed on the outer periphery of the coil bobbin 4b.

  FIG. 4 is a perspective view of an example of a coil bobbin according to the rotation prevention structure of the torque sensor of the present invention. In the rotation prevention structure of the torque sensor of the present invention, a connector portion for external output is provided on the outer periphery of the torque sensor 4. 4d is arrange | positioned as a convex part, this connector part 4d and the harness 8 are connected, and the output of a torque sensor is transmitted 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 anti-rotation structure of the present invention, the connector portion 4d may be formed integrally with the coil bobbin 4b, and formed separately from each other, and fixed to each other by bonding or screwing. Also good. In the structure for preventing rotation of the torque sensor of the present invention, the convex portion is not limited to the connector portion 4d, and a convex portion may be provided separately from the connector portion 4d.

  FIG. 5 is a perspective view of an example of a housing according to the torque sensor rotation prevention structure of the present invention. In the torque sensor rotation prevention structure of the present invention, the hollow housing 5 includes a connector portion 4d. The large-diameter portion 5a having an inner diameter into which the torque sensor 4 can be inserted, and the small-diameter portion 5b having an inner diameter smaller than the large-diameter portion 5a. When the torque sensor 4 is accommodated in the housing 5 so as to be coaxial with the housing 5 from the end on the large diameter portion 5a side to the end on the opposite side of the small diameter portion 5b, the connector portion 4d is engaged. An opening 5c having a possible width is provided. Therefore, with the magnetostrictive shaft 3 and the torque sensor 4 attached to the crankshaft 2, the crankshaft 2 is inserted from the large diameter portion 5a side of the housing 5, and the opening 5c of the housing 5 and the connector portion 4d of the torque sensor 4 are inserted. And the torque sensor 4 is accommodated in the housing 5 while engaging the connector portion 4d to function as a detent member for the torque sensor 4. Thereby, it is possible to prevent the torque sensor 4 from rotating with respect to the housing 5. Moreover, since the torque sensor 4 can be accommodated in the housing 5 in a state where the torque sensor 4 and the harness 8 are connected, the assembling work can be easily performed.

  Although it is conceivable that the housing 5 is not provided with the large-diameter portion 5a and the small-diameter portion 5b, an opening is provided from the axial end of the housing 5 having a constant inner diameter. However, as shown in FIGS. Considering the holding of the bearings 9 arranged at both ends in the axial direction, it is necessary to cover the bearing 9 around the entire circumference, and even if the strength of the housing 5 itself is taken into consideration, an opening is provided at the axial end of the housing Is not preferred. Therefore, it is preferable to provide the housing with the large-diameter portion 5a and the small-diameter portion 5b as described above.

  In the rotation prevention structure of the torque sensor of the present invention, the connector portion 4d (see FIGS. 1 and 2) has a hollow box shape, and the connector portion 4d and the harness 8 are connected inside the connector portion 4d. And it is preferable that the inside of the connector part 4d is sealed with resin. By covering the connecting portion between the connector portion 4d and the harness 8 with resin, it is possible to prevent moisture from entering the connector portion 4d and to prevent the harness 8 from being damaged due to an unexpected operation.

  The rotation prevention structure for a torque sensor according to the present invention can be rotated integrally with the crankshaft 2, the crankshaft 2, and disposed on the outer periphery of the magnetostrictive shaft 3. A torque sensor 4 for detecting torque acting on the magnetostrictive shaft 3 and a structure for preventing rotation of the torque sensor having a structure housed in the housing 5, the torque sensor 4 having a convex portion on the outer periphery, and The housing 5 is provided with an opening 5c with which the convex portion can be engaged, and it is only important that the convex portion is locked to the opening 5c.

  For example, as shown in FIGS. 1 and 2, the magnetostrictive shaft 3 is rotatably mounted via bearings 9 arranged on both sides in the axial direction inside a substantially cylindrical housing 5. A female screw portion 3c 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 3c 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 protrusion 2b protruding outward in the radial direction is provided on the end side adjacent to the male screw portion 2a at one end of the crankshaft 2 along the circumferential direction. 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 comes into contact with the protrusion 2b provided on the crankshaft 2. Can be made easier.

  Note that an adhesive may be applied to the female screw portion 3 c formed on the inner peripheral surface of one end of the magnetostrictive shaft 3 and the male screw portion 2 a provided on the outer peripheral surface of the crankshaft 2. The fastening portion between 3c and 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 3c and the male screw portion 2a can be prevented or suppressed from being loosened.

  The substantially central portion of the magnetostrictive shaft 3 is a large-diameter portion 3a having an inner diameter larger than the outer diameter of the crankshaft 2, and the inner peripheral surface of the large-diameter portion 3a of the magnetostrictive shaft 3 and the outer peripheral surface of the crankshaft 2 A space 10 is formed between them. Between the inner peripheral surface of the other end opposite to the one end where the female screw portion 3c of the magnetostrictive shaft 3 is formed and the outer peripheral surface of the crankshaft 2, the sliding bearing 11 as a bearing is free from rattling. Is intervening. The sliding bearing 11 and the drive sprocket 6 are restricted from moving in the crankshaft direction by a retaining member 12. In the illustrated example, an elastic member 13 is interposed between the slide bearing 11 and the retaining member 12. 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 12 includes a cylindrical part and a flange part, and the sliding part 11 of the sliding bearing 11 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 12 are fixed by screwing. 1 and 2, a female screw portion 3 d is provided on the inner peripheral surface of the magnetostrictive shaft 3, and a male screw portion 12 a is provided on the outer peripheral surface of the cylindrical portion of the retaining member 12. With this structure, the retaining member 12 can be firmly fixed to the magnetostrictive shaft 3.

  Further, as shown in the drawing, in the torque sensor rotation preventing structure of the present invention, it is preferable that an elastic member 13 is interposed between the retaining member 12 and the bearing (slip bearing 11 in the illustrated example). By adopting such a structure, it is possible to prevent dust and moisture from entering the crankshaft assembly. As the elastic member 13, for example, an O-ring or packing made of rubber or resin can be used.

  In the torque sensor rotation preventing structure of the present invention, as shown in FIG. 6, the torque sensor 4 includes a plurality of support members 14 disposed on both outer sides in the axial direction of the torque sensor 4. It is preferably sandwiched between the first support member 14a, the second support member 14b, and the third support member 14c. In the example shown in FIG. 6, a convex strip 3 e extending in the circumferential direction is provided on the outer periphery on one side of the magnetostrictive shaft 3, and on the outer periphery on the other side of the magnetostrictive shaft 7 with the magnetostrictive foil 7 interposed therebetween. A recess 3f extending in the circumferential direction is provided, and a clamping member 15 (snap ring 15 in the illustrated example) is fitted to the recess 3f. By the ridges 3e and the snap ring 15, the torque sensor 4 and the support members 14 arranged on both outer sides in the axial direction are sandwiched via wave washers 16 described later. By appropriately designing the thickness of the support member 14, the arrangement position of the torque sensor 4 in the axial direction can be determined.

  Further, as shown in the figure, stepped portions 4e are provided at both ends of the coil bobbin 4b of the torque sensor 4, and a support member that contacts the torque sensor 4 among the plurality of support members 14, in the illustrated example, the first support member 14a. The axial inner surface 14aa and the outer peripheral surface 14ab are in contact with the step 4e of the coil bobbin, and the inner peripheral surface 14ac is in contact with the magnetostrictive shaft 3, which is the detection shaft. Both radial positionings are possible. Further, although the torque sensor 4 is sandwiched through a plurality of support members 14, the contact surfaces of the support members 14 can be slid, so that the rotation of the torque sensor with respect to the magnetostrictive shaft 3 is prevented. Can do.

  In the torque sensor rotation preventing structure of the present invention, among the plurality of support members 14 arranged on both outer sides in the axial direction of the torque sensor 4, the outermost support member 14 in the axial direction (the support member 14c in the illustrated example). The innermost support member (support member 14a in the illustrated example) is made of a highly slidable material, so that the above 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 14 includes three pairs of support members 14a, 14b, and 14c. However, the structure for preventing rotation of the torque sensor according to the present invention is not limited thereto. 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 14b on the ridge 3e side of the three pairs of support members 14 shown in the figure is increased and the support member 14c is omitted may be employed.

  In the torque sensor rotation preventing structure of the present invention, at least one support member on the snap ring 15 side of the torque sensor 4 among the plurality of support members 14, for example, the second support member 14b, and the magnetostrictive shaft. 3 is preferably made of a magnetic material. With this configuration, the coil bobbin 4b is covered with the protrusion 3e integral with the magnetostrictive shaft 3, the yoke 4c, and the support member (support member 14b 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 for forming the support member 14 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 for forming the yoke 4c can be used. . The shape of the support member 14 is not particularly limited, but an annular shape as illustrated is preferable from the viewpoint of manufacturing cost and workability of assembly work.

  In the torque sensor rotation preventing structure of the present invention, as described above, the clamping member (snap ring 15 in the illustrated example) and the outermost support member 14 on the clamping member side (third in the illustrated example). An elastic member 16 (in the illustrated example, a wave washer 16) is preferably interposed between the support member 14c). By interposing the elastic member, the coil bobbin 4b is pressed against the protrusion 3e via the support member 14 even if the axial dimension of the snap ring 15 and the width dimension of the recess 3f 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 16, but a wave washer 16 is preferable as shown in the figure.

  Next, a method for applying the torque sensor rotation prevention structure of the present invention to the hanger pipe 1 will be described. FIG. 7 is an exploded perspective view showing a configuration of a bicycle hanger pipe to which the torque sensor rotation prevention structure of the present invention is applied. To apply the torque sensor rotation prevention structure of the present invention to the hanger pipe 1, FIG. The housing 5 having the torque sensor rotation prevention structure of the present invention is inserted 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 8 extending from the housing 5 is taken out is provided at the substantially central portion in the axial direction of the hanger pipe 1. 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 8 extends from the housing 5 by pulling out the harness 8 from the inside of the hanger pipe 1 to the outside through the opening 1 a and inserting the male screw 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.

  The bicycle 101 of the present invention is obtained by applying the torque sensor rotation prevention structure of the present invention to a hanger pipe 116 which is a support member attached to the lower part of a seat tube 105 along the width direction. The bicycle 101 of the present invention is not particularly limited except that the structure for preventing rotation of the torque sensor of the present invention is applied, and a known configuration can be adopted for other configurations.

DESCRIPTION OF SYMBOLS 1 Hanger pipe 1a Opening 1b Recess 1c Inclined surface 2 Crankshaft 2a Male thread part 2b Protrusion part 3 Magnetostrictive shaft 3a Large diameter part 3b Spline 3c, 3d Female thread part 3e Convex strip 3f Concave strip 4 Torque sensor 4a Concave 4c Coil bobbin 4c 4d Connector part (convex part)
4e Step part 5 Housing 5a Large diameter part 5b Small diameter part 5c Opening part 5d Flange part 5e Concave part 5f Male thread part 6 Drive sprocket (drive side rotating member)
7 Magnetostrictive foil 7a, 7b Slit 8 Harness 9 Bearing 10 Space 11 Sliding bearing (bearing)
12 Retaining Member 13 Elastic Member 14 Support Member 15 Nipping Member (Snap Ring)
16 Elastic member (wave washer)
Reference Signs List 17 Anti-rotation member 17a Main body portion 17b First engagement portion 17c Second engagement portion 18 Fixing member 18a Female thread portion 18b Abutting portion 18c Flange portion 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 (5)

A crankshaft, a magnetostrictive shaft that can rotate integrally with the crankshaft, and is disposed coaxially with the crankshaft, and a torque sensor that is disposed on the outer periphery of the magnetostrictive shaft and detects torque acting on the magnetostrictive shaft In the structure for preventing rotation of the torque sensor having a structure housed in the housing,
With the torque sensor is convex portion on the outer periphery, and said convex portion on the housing has opening sections engagement is provided, Ri said protrusions name locked to the opening,
A structure for preventing rotation of a torque sensor, wherein the housing has a structure housed in a hanger pipe .   The housing has a cylindrical large-diameter portion and a small-diameter portion, the large-diameter portion has an inner diameter into which the torque sensor having the convex portion can be inserted, and the opening is provided in the small-diameter portion. The structure for preventing rotation of a torque sensor according to claim 1. The convex portion is a connector portion for external output of the torque sensor, and the opening portion is directed from the end portion on the large diameter portion side to the opposite end portion of the small diameter portion, and the connector portion is engageable. 3. The structure for preventing rotation of a torque sensor according to claim 2, wherein the structure has a width, the connector part is engaged from the large diameter part side of the opening part, and the connector part is locked to the opening part.   The torque according to claim 3, wherein the connector part has a hollow box shape, the connector part and the harness are connected inside the connector part, and the inside of the connector part is sealed with resin. Sensor rotation prevention structure.   An electrically assisted bicycle, to which the structure for preventing rotation of a torque sensor according to any one of claims 1 to 4 is applied.

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