JP2006188160A - Power assisted bicycle and magnetizing method of position detecting magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve assisting performance, and to execute stable control by accurately detecting torque and providing a bending joint which can be easily assembled, in a power assisted bicycle. <P>SOLUTION: A spring opening at a tip end portion and having twist at both ends is fixed to an adaptor and a wheel through a slit-shaped fixing member attached so as not to apply surface pressure at each end of the spring. Sensor rings respectively fixed to the adaptor and the wheel are integrally magnetized while adding pressure to the adaptor, thereby making a torque detection origin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric assist type bicycle having both human power driving force and electric driving force, and more particularly to a method of magnetizing a bending joint and a position detecting magnet to be mounted on the bicycle.

  The electrically assisted bicycle has two driving forces, one of which is a driving force that rotates the wheel through the rotating side of the chain and the casing, and the other is a pedal. Is detected, the motor is rotated with a torque having a magnitude corresponding to the torque, and the wheels are driven via a speed reduction mechanism. For example, Patent Document 1 is known as such an electrically assisted bicycle. According to this Patent Document 1, the motor is arranged in the drive unit, and the drive motor is increased in speed for the purpose of reducing the size and weight of the structure, and the required torque is reduced by a gear or a pulley. Like to get.

  Conventional power-assisted bicycles have a reduction mechanism at the rear wheel, which increases the position of the product and hinders weight reduction and requires a major change in the basic structure of a normal bicycle. Has occurred and the cost is high. Further, when the charge voltage of the drive motor battery is lost during traveling, the manpower driving force required for traveling increases and fatigue occurs. Furthermore, since a motor having a brush is employed as the drive motor, the transmission efficiency between the motor and the running tire is low, and even if regenerative braking is performed, braking energy is absorbed by the loss of the motor and transmission mechanism, and the battery is It has problems such as being unable to charge.

As a means for solving the problems of Patent Document 1, Patent Document 2 is known. In this patent document 2, a motor controlled by a torque proportional to a human driving force transmitted from a pedal through a chain is an outer rotor type DC brushless motor, which is coupled with a human power transmission mechanism without gears. The human driving force is detected by the torsional torque generated in the above.
Japanese Patent Laid-Open No. 10-324288 JP 2002-46685 A

  As in Patent Document 2, a human power transmission mechanism as a torque transmission path that transmits a pedaling force of a person to a rear wheel tire must be displaced in order to detect torque generated there, and mechanically. In the past, there has been no flexible joint that requires strength and deflection, and has an appropriate structure with a simple structure that affects motor control and bicycle riding comfort. Further, the magnet for detecting the pedal depression force has an unstable control performance because the set torque of the assist motor cannot be determined due to variations in the torque detection origin.

  Accordingly, an object of the present invention is to provide a bending joint and a method for magnetizing its position detecting magnet with good torque detection accuracy and easy mounting.

A first aspect of the present invention is an electrically assisted bicycle having both a human driving force and an electric driving force composed of a permanent magnet, and transmits torque obtained by human power to a rotating part via a bending joint.
The flexible joint has a ring-shaped spring having an opening at the tip and a twist, and a notch larger than the thickness of the spring, and each tip of the sprig is attached to the notch with a gap 2 It is characterized by comprising a single fixing member.

  According to a second aspect of the present invention, the cut portions of the two fixing members are formed in a step shape, and the tips of the springs are attached to the step portions of the step shape with gaps, respectively. It is.

  According to a third aspect of the present invention, the flexible joint is disposed between an adapter integrally formed with a sprocket for transmitting a pedaling force of a pedal and a wheel as a rotating portion, and the adapter and the wheel have a position detecting magnet. Each of the sensor rings is provided with a feature.

  According to a fourth aspect of the present invention, the spring is a ring-shaped spring having about 0.8 turns.

  According to a fifth aspect of the present invention, one of the two fixing members is fixed to the adapter at the portion without the cut portion, and the other is fixed at the wheel to the wheel without the cut portion. Each of the notch portions is characterized in that one end of the spring is attached with a gap so as to be in a free state where no surface pressure is applied.

A sixth aspect of the present invention is an electrically assisted bicycle having both human power driving force and electric driving force composed of permanent magnets, and the torque obtained by human power is applied to the wheel of the rotating part via a pedal, an adapter and a flexible joint. In what to communicate,
A sensor ring is provided on each of the adapter and the wheel, and each sensor ring is magnetized integrally with a pressure applied to the adapter.

  A seventh aspect of the present invention is characterized in that the pressurizing pressure is a pressure that becomes a torque detection origin of the pedal depression force.

  As described above, according to the present invention, since it is attached in a free state between the spring and the fixing member constituting the bending joint so that no residual pressurization occurs, the hysteresis that is bent by the pedal effort is extremely reduced. The detection accuracy is improved and the assist rate control performance is enhanced. In addition, since the two magnets that detect pedal depression force are magnetized together after applying pressure to the origin of torque detection in the pedal depression force direction, torque detection can always be detected from the origin without variation, Furthermore, the assist rate control performance is improved.

  FIG. 1 shows a configuration diagram of a drive unit in which the present invention is used, where 1 is an axle, 2 is a bearing fitted to the axle, and a sprocket 4 is integrally formed on the outside via an adapter 3. It is pivotally fixed. Although not shown in the drawings, the sprocket 4 has a chain connected to the pedal. Reference numeral 5 denotes a wheel, which is formed in a disk shape and has a hollow portion, the inner diameter side of which is connected to the adapter 3 via a bearing 6, and a spoke to which a wheel spoke is attached on the outside. A hole 7 is formed. The hollow portion of the wheel 5 is configured to be hermetically sealed, and is disposed so as to extend in the outer diameter direction of the columnar plate 8 fixed to the axle 1. A fixed iron core 9 is disposed along the circumferential direction at the tip of the support plate 8, and a stator winding 10 is wound around the fixed iron core 9. Further, on the inner surface of the wheel 5 facing the stator core 9, permanent magnets 11 are alternately arranged with N and S poles along the circumference via a gap G to form a rotor.

  Reference numeral 12 denotes a yoke portion installed on the wheel 5, and an outer rotor type permanent magnet synchronous motor is constituted by these 9 to 12, and the rotor and tire portion of this motor are stretched and connected by spokes. The tire can be driven efficiently without providing a speed reduction mechanism. Reference numeral 13 denotes a printed board. On the printed board 13, elements of a power conversion unit (not shown) and circuit parts of a control unit for controlling the elements are mounted and fixed to the support plate 8 with bolts or the like. Yes. Reference numeral 20 denotes a bending joint according to the present invention, which is disposed between the flange 3a of the adapter 3 and the wheel 5 facing the flange 3a. Reference numeral 14 denotes a first sensor ring (magnet) attached to the flange 3a of the adapter, 15 denotes a second sensor ring (magnet) attached to the step of the wheel 5, and the first sensor ring 14 is second. The diameter is smaller than that of the sensor ring 15. Each sensor ring is magnetized so that N and S poles are alternately formed. In addition, on the fixed side of the position facing each sensor ring, position detectors 16 and 17 made of Hall elements or the like are disposed and fixed to the column plate 8.

  The bending joint 20 includes a spring 21 as shown in FIG. 2 and a fixing member (nut) 22 as shown in FIG. The spring 21 is a ring-shaped one, but it is not a complete ring-shaped one that is connected, but about 0.8 turns are used, and the tip of the opening is twisted in the vertical direction. Thus, fixing holes 21a and 21b are formed. Two nuts 22 are used, each having a stepped shape, and a screw hole 23b is screwed in the lower step portion, and a screw hole 23 is screwed in the non-high step portion. ing.

  As shown in FIG. 4, the two nuts 22 (22a, 22b) having a step are respectively arranged in the respective holes 21a, 21b on the front end side where the springs 21 are opened. As shown by, one is fixed to the wheel 5 and the other is fixed to the flange 3a of the adapter 3 via bolts. As a fixing method, the step nut 22a is fixed to the side surface of the flange portion 3a of the adapter with the bolt 24b, one end of the spring 21 is inserted into the notch space portion of the step nut 22a, and the bolt 24a is attached to the flange portion 3a of the adapter. Install. A step nut 22b for attaching the other end of the spring 21 is fixed to the wheel 5 by a bolt 24c, and the tip end of the spring 21 is inserted into a notch space portion of the step nut and is attached via a bolt 24d. As shown in FIG. 4, the state of the spring 21 and the step nut 22 after the attachment is such that a gap W1 is formed between the nut step and the tip of the spring, and a gap W2 is formed between the nuts. So that the spring is in a movable state and is not subjected to surface pressure. Therefore, the holes 21a and 21b drilled in the spring are formed to be larger than the diameters of the bolts 24b and 24d. In addition, although the fixing member 22 shown in FIG. 3 is fastened with a nut formed in a stepped shape, the fixing member 22 may not be a stepped shape but may be a notch-shaped cutout portion larger than the thickness of the spring.

  In the electrically assisted bicycle constructed as described above, a driving force is transmitted to the wheel 5 through the sprocket 4, the adapter 3, and the flexible joint 20 by stepping on the pedal, and these are supported by the bearings 2 and 6 to be axles. Rotate 1 up. By this rotation, the permanent magnet 11 fixed to the wheel 5 is also rotated, and the attraction force generated between the rotating permanent magnet 11 and the stator winding 10 is used, and the rotor position detector (not shown) is used. The rotation is continued by switching the direction of the current flowing through the stator winding 10 according to the detected position signal.

  On the other hand, the sensor rings 14 and 15 magnetized so that a plurality of N and S poles are alternately arranged in a manner similar to the rotation radius by a method described later has a phase difference corresponding to the twist of the bending joint 20 caused by the pedal depression force. Detected. This signal is introduced as a human driving force into the control circuit of the power converter, and is used as the assist torque setting value for the permanent magnet type synchronous motor. That is, since the torque of the permanent magnet synchronous motor is proportional to the current, an error signal between the torque setting value and the detected current is obtained, a PWM signal is generated according to the error signal, and an inverter as a power converter is installed. To control and drive the motor as human-powered assist.

FIG. 6 is a perspective view of the adapter 3 to which the sensor ring 14 is fixed, and FIG. 7 is a front view as seen from the inside of the wheel 5 to which the sensor ring 15 is fixed. FIG. 8 is an assembled view of the adapter 3, the wheel 5, the sensor rings 14 and 15, and the flexible joint 20. The two sensor rings 14 and 15 having different diameters are magnets, which are alternately arranged with N poles and S poles, and both are arranged with the same polarity of a plurality of poles. Then, when the bending joint 20 is bent according to the pedal depression force, it is rotationally displaced between the magnets (sensor rings) 14 and 15, and a phase difference is generated in the magnetic flux detected by the position detectors 16 and 17.
At this time, the magnets 14 and 15 are connected by the bending joint 20, and the positional relationship between the two in an unloaded state should not be changed by receiving a repeated load caused by the pedaling force. That is, at the torque detection origin at which the load is applied from the no-load state, the phases of the two magnets 14 and 15 must always match. However, in the past, it is not possible to match the phases at the torque detection origin. It was difficult.

  In the present invention, an interval between W1 and W2 is provided at the tip of the spring 21 constituting the flexible joint so that the positional relationship between the two in a free state at no load does not change. As shown in the figure, after each sensor ring is attached to the adapter 3 and the wheel 5, a pressure is applied to the adapter 3, and in this state, the sensor rings 14 and 15 are magnetized integrally by a well-known method to make the torque detection origin constant. ing.

Further, the reason why the bending joint 20 is configured as described above is as follows.
There are various methods for arranging the flexible joint between the adapter 3 and the wheel 5. For example, a spring is used as a bending joint as in the present invention, and both ends of the spring are clamped by screws and fixed by surface pressure. In this case, due to the dimensional constraints, the spring cannot be completely fixed by the surface pressure due to screwing, and there is a clearance around the spring mounting hole, resulting in a position shift corresponding to that amount due to the external force after assembly, and the remaining spring It is held in a state with pressurization. In such a state, the following problem occurs.
(1) Since the spring bends in response to the increase or decrease of the pedal depression force from the state where the residual pressure is applied, the hysteresis of the spring deflection characteristic is increased, which affects the detection system. (2) The residual pressurization state of the spring is not easy to apply a load equivalent to the pedal depression force in the assembly process, and the equipment is too large to be suitable for mass production. Also, with a simple load, the residual pressure state varies and the initial state (torque detection origin) is not stable.

  In the above-described present invention, as shown in FIG. 4 or FIG. 5, a step having a size slightly larger than the thickness of the spring 21 and nuts 22 a and 22 b having two screw holes 23 a and 23 b are used, and there is no step between the nuts. The high part is fixed to the adapter 3 and the wheel 5 via bolts 24b and 24c. And the front-end | tip of the spring 21 is inserted in each level | step-difference part of each nut 22a, 22b, respectively, and it attaches with bolt 24a, 24d. As a result, the adapter 3 and the wheel 5 are connected by the spring 21, and the spring 21 is attached in a free state without residual pressure by the gap of the step portion of the nut. Accordingly, since the spring 21 is bent by the pedal depression force from the natural length, the hysteresis is extremely small, and the influence on the detection accuracy is negligible. In addition, the torque detection origin can be established with a small load in the assembly process. Become.

The partial longitudinal section front view showing the embodiment of the present invention. The block diagram of the spring used for this invention. The block diagram of the fixing member used for this invention. The assembly partial drawing of a bending joint. Installation explanatory drawing of a bending joint. The perspective view which shows the adhering state of a 1st sensor ring. The front view which shows the adhering state of a 2nd sensor ring. Explanatory drawing of the assembly completion state of a bending joint part.

Explanation of symbols

1 ... Axle
2, 6 ... Bearing
3 ... Adapter
4 ... Sprocket
5 ... Wheel
7 ... Spoke holes
8 ... Staff plate
9 ... Stator core
10 ... Stator winding
DESCRIPTION OF SYMBOLS 11 ... Permanent magnet 14, 15 ... 1st and 2nd sensor ring 16, 17 ... Position detection part 20 ... Deflection joint 21 ... Spring 22 ... Fixing member (nut)

Claims (7)

An electrically assisted bicycle having both a human driving force and an electric driving force composed of a permanent magnet, which transmits torque obtained by human power to a rotating part via a bending joint,
The flexible joint has a ring-shaped spring having an opening at the tip and a twist, and a notch larger than the thickness of the spring, and each tip of the sprig is attached to the notch with a gap 2 An electrically assisted bicycle characterized by comprising a single fixing member. 2. The electric assist type according to claim 1, wherein the cut portions of the two fixing members are formed in a stepped shape, and each tip of the spring is attached to the stepped stepped portion with a gap. bicycle. The flexible joint is disposed between an adapter that is integrated with a sprocket that transmits the pedaling force of the pedal and a wheel that is a rotating part, and a sensor ring that serves as a position detection magnet is disposed on the adapter and the wheel. The electrically assisted bicycle according to claim 1 or 2, characterized in that it is provided. 4. The electrically assisted bicycle according to claim 1, wherein the spring is a ring-shaped spring having about 0.8 turns. One of the two fixing members is fixed to the adapter at the portion without the cut portion, and the other is fixed to the wheel at the portion without the cut portion. 5. The electric assist type bicycle according to claim 1, wherein one end is attached with a gap so as to be in a free state where no surface pressure is applied. In an electrically assisted bicycle having both a human driving force and an electric driving force composed of a permanent magnet, which transmits torque obtained by human power to a wheel of a rotating part via a pedal, an adapter and a flexure joint,
A magnetizing method for a position detecting magnet for an electrically assisted bicycle, wherein a sensor ring is provided on each of the adapter and the wheel, and each sensor ring is magnetized integrally with a pressure applied to the adapter. 7. The method of magnetizing a position detecting magnet for an electrically assisted bicycle according to claim 6, wherein the pressurizing pressure is a pressure serving as a torque detection origin of a pedal depression force.