JP2003130158A - Method for controlling power transmission device, automobile, bicycle and motor with frictional roller- type variable-speed machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling a power transmission device and a motor, using a frictional roller-type variable-speed machine which can be used to surely prevent the shaft of the motor from being taken around. SOLUTION: The power transmission device 1 is forced to transmit rotational power via the frictional roller-type variable-speed machine 21 from the shaft of the motor 2. A switching means 7 is provided, by which the lead lines 14, 15 of the motor 2 are switched to short-circuit, when a torque acting in order to take around the shaft of the motor 2, at least from the side of the frictional roller-type variable-speed machine 21 is operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrically assisted bicycle or an electrically assisted wheelchair having two power sources of human power and a motor, a hybrid electric vehicle having two powers of an engine and a motor, and an air conditioner for a motor integrated vehicle. It operates even when the motor that is the drive source is in a stopped state, such as a hybrid air conditioner that can be driven by engine power as well as a starter directly connected to the engine for idle stop (for example, in an electric assist bicycle, even if the motor is stopped, the pedal is operated). A power transmission device having a mode of rotating and propelling a vehicle with human power). The present invention also relates to a method of controlling a motor with a friction roller type transmission.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram of a power transmission device in an electrically assisted bicycle or the like. In order to drive a load 101 such as a gear of a bicycle, a first input portion 102 such as a pedal, which is manually operated, and a second input portion 10 which is an electric motor.
3 and 3 are provided in parallel with each other. A speed reducer 104 is provided at the rear stage of the electric motor 103, which has a higher torque but a lower torque than the first input unit 102, in order to reduce the rotational power from the motor 103 and increase the torque. . A driving force applied from the first input unit 102 is detected by a sensor (not shown), and a driving force corresponding to the driving force is detected by the motor 1
03 is generated and drives the load 101 even if the force applied to the first input unit 102 is small. That is, the drive torque T2 corresponding to the drive torque T1 generated in the first input unit 102 is generated by the motor 103 and the speed reducer 104. Then, the driving torque T1 and the driving torque T2 are merged at the merging portion 105, and the driving torque T3 that is the sum of the driving torques T1 and T2 (T3 = T1 + T2 when the loss due to friction or the like is not taken into consideration) is applied to the load 101. To drive.

By the way, in the case of an electrically assisted bicycle, for example, when the pedal is energized in spite of a gentle downhill or strong wind, the torque T3 required to drive the load 101 is first. The drive torque T1 applied to the input unit 102 may increase (T1> T3). In such a case (when the rotation on the driven side exceeds the rotation of the motor), an excess of the driving torque T1 applied to the first input unit 102 that exceeds the torque T3 required for driving the load 101 is exceeded. Torque (T1-T3) is
As indicated by an arrow, the reverse flow from the merging portion 105 to the motor 103 through the speed reducer 104. Then, the rotor of this motor 103 is rotated. As a result, the drive torque T1 applied to the first input unit 102 is not effectively used to drive the load 101, and the force required to generate the drive torque T1 at the first input unit 102 (for example, pedaling is performed). The force required for) will increase.

In order to eliminate such inconvenience, conventionally, a one-way clutch is provided between the speed reducer 104 and the merging portion 105 so that power is transmitted only from the speed reducer 104 to the merging portion 105. ing. JP-A-10-311
Japanese Unexamined Patent Publication No. 398 discloses that a wedge roller (registered trademark) type friction roller type transmission is provided as the speed reducer 104 instead of providing a one-way clutch between the speed reducer 104 and the merging portion 105. . This friction roller type transmission uses the wedge action of wedge rollers (movable rollers) to transmit rotational power from the input shaft to the output shaft.

[0005]

In a conventional power transmission device equipped with the above-mentioned wedge roller type friction roller type transmission (hereinafter also referred to as "wedge roller speed reducer"), a wedge roller is provided in the rotation direction of the motor. While the speed reducer transmits power, when the rotation on the driven side exceeds the rotation of the motor, the wedge roller speed reducer idles, so that the rotation on the driven side is not hindered. However, when the idle rotation torque of the wedge roller reducer is heavy, the wedge roller reducer does not idle and rotates the motor 103 together, and the motor 103
May be adversely affected. In particular, when a brush motor is used as the motor 103, the abrasion of the brush is accelerated due to the accompanying rotation, and the life of the brush is shortened.
The generation of dust may adversely affect surrounding bearings and the like. The present invention has been made in view of the above circumstances, and an object thereof is to provide a power transmission device and a method for controlling a motor with a friction roller type transmission that can reliably prevent the shaft of the motor from being rotated. Especially.

[0006]

An object of the present invention is a power transmission device for transmitting rotational power from a shaft of a motor through a friction roller type transmission, wherein the friction roller type transmission is provided on the shaft. A center roller that is concentrically fixed and has an outer peripheral surface as a first cylindrical surface; an outer ring that has an inner peripheral surface as a second cylindrical surface and is rotatably provided around the center roller relative to the center roller; An output shaft concentrically fixed to the outer ring, three or more pivots arranged in parallel with the central roller in the annular space between the first cylindrical surface and the second cylindrical surface, and each of these pivots The ring-shaped ring is rotatably supported and has three or more intermediate rollers each having an outer peripheral surface as a third cylindrical surface, and the center of the center roller and the center of the outer ring and the output shaft are eccentric to each other. Circumferential space width dimension And at least one intermediate roller among the three or more intermediate rollers is supported as a movable roller so as to be slightly displaceable in the circumferential direction of the annular space, and the remaining intermediate rollers are used as guide rollers. , The center roller is configured to move the movable roller toward a portion of the annular space having a small width dimension when the center roller rotates in a predetermined direction, and the shaft of the motor is at least from the friction roller type transmission side. It is achieved by a power transmission device including switching means for switching the lead wire of the motor so as to be short-circuited when a torque for rotating the motor is applied. Another object of the present invention is a method of controlling a motor with a friction roller type transmission that transmits rotational power from a shaft of the motor through a friction roller type transmission, wherein the friction roller type transmission is provided on the shaft. A central roller fixed concentrically and having an outer peripheral surface as a first cylindrical surface, an outer ring provided around the central roller having an inner peripheral surface as a second cylindrical surface and rotatable relative to the central roller, and An output shaft concentrically fixed to the outer ring, three or more pivots arranged in parallel with the central roller in an annular space between the first cylindrical surface and the second cylindrical surface, and each of these pivots. The annular ring is rotatably supported and has three or more intermediate rollers each having an outer peripheral surface as a third cylindrical surface, and the center of the center roller and the centers of the outer ring and the output shaft are eccentric. Circle width dimension The intermediate rollers are made non-uniform in the direction, and at least one of the three or more intermediate rollers is supported as a movable roller so as to be slightly displaceable in the circumferential direction of the annular space, while the remaining intermediate rollers are guide rollers. age,
When the center roller rotates in a predetermined direction, the movable roller is configured to move toward a portion having a narrow width dimension of the annular space, and at least the shaft of the motor is disposed from the friction roller type transmission side. This is achieved by a method of controlling a motor with a friction roller type transmission, characterized in that a lead wire of the motor is short-circuited when a torque that tends to rotate together acts.

According to the above construction, it is possible to surely prevent the shaft from being rotated together by short-circuit braking the motor by the switching means, so that the motor is not adversely affected. The switching means short-circuits the lead wire of the motor when the motor is stopped or when the shaft of the motor is rotating, and at least the torque for rotating the shaft from the friction roller type transmission acts. In doing so, the switching means shorts the leads. Even when the friction roller type transmission normally operates and the torque for rotating the shaft from the friction roller type transmission side does not act, it is preferable that the lead wire be short-circuited by the switching means.

In the above structure, it is preferable that the switching means is switched so as to supply electric power from a power source to the motor. In this way, by allowing the switching means to also have a plurality of functions, the number of parts can be reduced, and the cost can be reduced. Further, in the above structure, it is preferable that the switching means is switched so as to open the lead wire of the motor.
By doing this, when the friction roller or the one-way clutch burns, and the large torque that tries to rotate the shaft acts from the one-way clutch side (at the time of abnormality), the motor lead wire is opened. And try to rotate the motor. By doing this, compared to when the motor is stopped by short-circuiting the lead wires, the load torque from the driven side can be reduced, the operation suddenly stops, and the power transmission member is forced. It can prevent damage. Further, in the above configuration, it is preferable that the switching means is a relay. This makes it possible to inexpensively configure a circuit for short-circuiting the lead wires by automatic control. Further, in the above structure, it is preferable that the motor is a brush motor. According to the present invention, since there is no fear of damage to the brush, an inexpensive brush motor can be used with confidence. Further, in the above structure, it is preferable that a one-way clutch is further provided at the rear stage or the front stage of the friction roller type transmission. With this, the friction roller type transmission and the one-way clutch cooperate to more reliably prevent the motor from rotating together. As the one-way clutch, for example, a roller clutch disclosed in Japanese Patent Laid-Open No. 2000-27896 can be used. Also,
In the above structure, it is preferable that a one-way clutch is provided at a rear stage of the friction roller type transmission, and the idling torque of the one-way clutch is lower than the idling torque of the friction roller type transmission. This ensures that the idling torque of the friction roller type transmission is heavier than that of the one-way clutch when the torque to rotate the motor from the driven side acts, so that the one-way clutch is surely idle. Can be made. Then, it is possible to reliably prevent the seizure of the friction roller type transmission. Further, in the above configuration, it is preferable that the output shaft of the friction roller type transmission is connected to the crank shaft of the vehicle engine. An appropriate transmission may be provided between the output shaft and the crankshaft of the friction roller type transmission. Further, in the above structure, it is preferable that the output shaft of the friction roller type transmission is connected to the pedal shaft of the bicycle. An appropriate transmission may be provided between the output shaft and the crankshaft of the friction roller type transmission.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 schematically shows a power transmission device 1 according to a first embodiment, which is applied to a starting device for an automobile engine such as a hybrid electric vehicle. The power transmission device 1 is connected to a starter motor (hereinafter abbreviated as a motor) 2 that is rotationally driven by power supply from a power source E, a wedge roller speed reducer 21 provided on the motor 2, and a wedge roller speed reducer 21. The one-way clutch 3 and the switching means 7 for switching the electric power supply to the motor 2 according to the driving state of the engine 4 are provided. An endless belt (timing belt) 6 is wound around a pulley 5 fixed to a shaft (crankshaft) 4a of the engine 4 and a pulley 27 fixed to an output shaft of the one-way clutch 3. The pulleys 27, 5 and the belt 6 constitute a speed reducer. A transmission 9 is provided on the load side of the engine 4 via a flywheel 8. The engine 4 automatically stops (idle stop) when the vehicle is stopped.

In this embodiment, a brush motor is used as the motor 2 and a relay is used as the switching means 7. The switching means 7 includes two fixed terminals 11 and 12 and one movable terminal 13. Whether one of the fixed terminals 11 and 12 of the switching means 7 is turned on by driving the movable terminal 13 based on a command from a control means such as a computer (not shown),
Or, there are three position contacts that are both turned off at the same time. The plus side of the power source E is connected to one lead wire 14 of the motor 2 via the fixed terminal 12, and the minus side is connected to the other lead wire 15.

The wedge roller speed reducer 21 and the one-way clutch 3 transmit the rotational power of the motor 2 to the engine 4, but run idle when the rotational power from the engine 4 to the motor 2 acts. The idling torque of the one-way clutch 3 is set lower than the idling torque of the wedge roller speed reducer 21.
By providing the one-way clutch 3, it is possible to make a setting such that the idling performance of the wedge roller speed reducer 21 is slightly sacrificed and the pressing force between the rollers described later is increased.

Next, the operation of the power transmission device 1 will be described.
At the time of starting (during cranking), the fixed terminal 12 is switched to the ON state by the movable terminal 13 as shown in FIG. As a result, the motor 2 is energized via the lead wires 14 and 15, and the shaft of the motor 2 rotates in one direction. At the same time, the output shafts of the wedge roller speed reducer 21 and the one-way clutch 3 rotate in one direction, the pulley 5 is driven by the timing belt 6, and the shaft 4a fixed to the pulley 5 is driven.
Is driven to rotate and the engine 4 is started.

When the engine is rotating, the switching means 7
2 drives the movable terminal 13 to switch the fixed terminal 11 to the on state and the fixed terminal 12 to the off state as shown in FIG. As a result, the power supply to the motor 2 is cut off, the lead wires 14 and 15 are short-circuited via the fixed terminal 11, and the motor 2 is short-circuited and braked. At this time, the accompanying torque of the motor 2 increases, and the idling torque of the wedge roller speed reducer 21 and the idling torque of the one-way clutch 3 are surely smaller than the accompanying torque. Therefore, the rotational power of the engine 4 acts on the one-way clutch 3 via the pulley 5 and the belt 6, but the one-way clutch 3 idles and the stopped state of the motor 2 is maintained.
Even if the one-way clutch 3 is slightly rotated, the wedge roller speed reducer 21 idles and the stopped state of the motor 2 is maintained.

Next, the operation when an abnormality occurs will be described. For example, if the one-way clutch 3 or the wedge roller speed reducer 21 sticks, the rotation of the engine 4 is transmitted to the motor 2 and the load on the engine 4 increases. To prevent this
By detecting torque, temperature, vibration, etc., such an abnormal occurrence is detected, and as shown in FIG.
3 is driven to the neutral position, and both the fixed terminals 11 and 12 are turned off. As a result, the lead wires 14 and 15
Is in the open state, that is, both ends of the armature coil of the motor 2 are in the open state, and the counter electromotive voltage is not generated. Therefore, the accompanying torque of the motor 2 decreases, the rotation of the shaft of the motor 2 is allowed, and an excessive load is not applied to the engine 4.

According to the power transmission device 1 as described above, even if the one-way clutch 3 or the wedge roller reducer 21 fails, an excessive load is applied to the engine 4, the motor 2 or the switching device is switched. It is possible to prevent the means 7 from being damaged and it is possible to drive the vehicle safely and comfortably.

Next, the wedge roller speed reducer 21 will be described in detail. FIG. 4 shows an example of the wedge roller reducer. The wedge roller speed reducer 21 has a built-in one-way clutch 3 in the same housing and is integrally provided with the motor 2 to form a drive unit. Figure 5
FIG. 6 is a sectional view taken along line YY in FIG. 4.

As shown in FIG. 4, the wedge roller reducer 2
1 is a central roller 2 having an outer peripheral surface as a first cylindrical surface 23a.
3 and an outer ring 26 having an inner peripheral surface as a second cylindrical surface 26a and provided around the center roller 23 so as to be rotatable relative to the center roller 23. Central roller 23
Is fixed to the end of the first rotating shaft (the shaft 2a of the motor) concentrically with the first rotating shaft, and the outer ring 26 has the end of the second rotating shaft (output shaft) 26b. It is fixed concentrically with. The second rotary shaft 26b is formed in a cylindrical shape here, and the roller clutch 3 as a one-way clutch is provided therein.

As shown in FIG. 5, three pivots 29a, 29b, 29b are provided in the annular space between the first cylindrical surface 23a and the second cylindrical surface 26a, and the central roller 23 and the outer ring 2 are provided.
6 is arranged in parallel. Each of these pivots 29a, 29
intermediate rollers 24a, 24b, 24c by b, 29b
Is rotatably supported. Each of these intermediate rollers 2
The outer peripheral surfaces of 4a, 24b, and 24c are third cylindrical surfaces 28, and the third cylindrical surfaces 28 are in contact with the first and second cylindrical surfaces 23a and 26a. By making the center of the center roller 23 and the center of the outer ring 26 eccentric, the width dimension of the annular space is made non-uniform in the circumferential direction. Then, the three intermediate rollers 24a, 24
One intermediate roller 24a of b and 24c is supported as a movable roller while being supported so as to be slightly displaceable in the circumferential direction of the annular space. It is elastically pressed toward the narrow portion of the annular space.

In FIG. 5, when the center roller 23 rotates in the clockwise direction, the intermediate roller 24a, which is a movable roller, is rotated by the pivot 29.
It rotates counterclockwise about a and the outer ring 26 also rotates counterclockwise. In this way, the rotation of the center roller 23 is transmitted to the outer ring 26. The rotary power transmitted to the outer ring 26 is further transmitted to the pulley 27 via the second rotary shaft 26b shown in FIG. 4, the roller clutch 3, and the output shaft 25 of the roller clutch 3. Wedge roller reducer 21
For a more detailed explanation of the operation, see Japanese Patent Laid-Open No. 10-311398
It is disclosed in Japanese Patent Publication No. A more detailed description of the operation of the roller clutch 3 is disclosed in Japanese Patent Laid-Open No. 2000-27896.

Another example of the wedge roller reducer is shown in FIG. In the wedge roller speed reducer 21 ′ of FIG. 6, the other end of the output shaft 25 having the pulley 27 at one end is concentrically fixed to the second rotating shaft 26b ′ that is concentrically connected to the outer ring 26. . This wedge roller reducer 21 'does not have a one-way clutch. Such wedge roller reducer 21 '
May be applied to the power transmission device 1 shown in FIGS. 1 to 3 or the power transmission device of the second embodiment described below.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 7 is a schematic perspective view showing a drive system of the electrically assisted bicycle. The members having the same functions as those already described in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. A wedge roller speed reducer 21 is provided on the shaft of the motor (brush motor) 2 in the power transmission device 31 of the present embodiment, and a small diameter gear 32 is provided on the output shaft of the wedge roller speed reducer 21. The small-diameter gear 32 meshes with the large-diameter gear 33. A pedal shaft 35 is connected to the large-diameter gear 33 via a bevel gear 34. These gears 32, 33, 34
Constitutes a speed reducer. That is, also in this embodiment, the speed reducer is provided at the rear stage of the wedge roller speed reducer 21.

The switching means 37 of this embodiment has two
It is configured as a position contact, and does not switch the movable contact 13 to the neutral position as shown in FIG. A relay can be used as the switching means 37.

When starting to ride an electrically assisted bicycle in which the power transmission device 31 is incorporated, or when climbing an uphill, the fixed terminal 12 is turned on by the movable terminal 13 as shown in FIG. As a result, the lead wire 1
Electric power is supplied from the power source E to the motor 2 via 4, 15 and the motor 2 is rotationally driven. The rotational power of the motor 2 rotates the output shaft of the wedge roller reducer 21 and is transmitted to the pedal shaft 35 via the reducer. As a result, the rotational power of the motor 2 is added to the force of stepping on the pedal 36 manually, so that the bicycle can be easily traveled.

On the other hand, when going downhill, the motor 2
When the assistance by is unnecessary, the movable terminal 13 is driven to switch the fixed terminal 11 to the on state and the fixed terminal 12 to the off state. Then, the electric power from the power source E supplied to the motor 2 is cut off, and the lead wire 1
4, 15 are short-circuited. As a result, the motor 2 is short-circuited and the wedge roller speed reducer 21 runs idle even if the pedal shaft 36 is rotated manually.

The power transmission device 31 as described above can be constructed at low cost because the switching means 37 is a two-position contact.

The present invention is not limited to the above-described embodiment, but can be appropriately modified and improved. For example, the one-way clutch may be provided not at the rear stage of the wedge roller reducer but at the front stage of the wedge roller reducer (between the wedge roller reducer and the motor).

[0027]

As described above, according to the present invention,
A power transmission device and a method for controlling a motor with a friction roller type transmission that can reliably prevent the shaft of the motor from being rotated.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation of the first embodiment.

FIG. 3 is a diagram illustrating the operation of the first embodiment.

FIG. 4 is a diagram showing an example of a wedge roller speed reducer.

5 is a cross-sectional view taken along line YY in FIG.

FIG. 6 is a diagram showing another example of a wedge roller speed reducer.

FIG. 7 is a perspective view of a main part for explaining a second embodiment of the present invention.

FIG. 8 is a block diagram illustrating an example of a conventional power transmission device.

FIG. 9 is a block diagram illustrating an example of a conventional power transmission device.

[Explanation of symbols]

1, 31 Power transmission device 2 Motor (motor with friction roller type transmission) 3 One-way clutch 7, 37 Switching means 14, 15 Lead wire 21 Wedge roller speed reducer (friction roller type transmission) E Power source

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B62M 23/02 B60K 9/00 EF term (reference) 3D039 AA01 AA02 AA03 AB27 AC06 AC21 AD02 AD11 AD53 3J051 AA01 BA03 BB02 BD01 BE03 BE04 EA01 EA03 ED04 ED18 FA01 FA02 FA08 5H115 PA11 PC06 PG04 PG10 PI13 PI29 PU02 PU22 PU25 PU30 QI03 SE03 SE08 SE09

Claims (12)

[Claims] 1. A power transmission device for transmitting rotational power from a shaft of a motor via a friction roller type transmission, wherein the friction roller type transmission is concentrically fixed to the shaft and has an outer peripheral surface as a first surface. A center roller having a cylindrical surface, an outer ring provided with an inner peripheral surface as a second cylindrical surface around the center roller so as to be rotatable relative to the center roller, and an output shaft concentrically fixed to the outer ring. , Three or more pivots arranged parallel to the central roller in an annular space between the first cylindrical surface and the second cylindrical surface, and each outer peripheral surface rotatably supported by each of these pivots. Is provided as a third cylindrical surface, and three or more intermediate rollers are provided, and the center of the center roller and the center of the outer ring and the output shaft are eccentric, whereby the width dimension of the annular space becomes uneven in the circumferential direction. Make uniform, 3 At least one of the above intermediate rollers is supported as a movable roller by supporting it so as to be slightly displaceable in the circumferential direction of the annular space, and the remaining intermediate rollers are used as guide rollers, and the central roller is in a predetermined direction. When the rotary roller is rotated, the movable roller is configured to move toward a narrow width portion of the annular space, and at least the torque for rotating the shaft of the motor from the friction roller type transmission is applied. A power transmission device comprising switching means for switching to short-circuit the lead wire of the motor when the power transmission device operates. 2. The power transmission device according to claim 1, wherein the switching means also switches to supply electric power from a power source to the motor. 3. The power transmission device according to claim 1, wherein the switching means also switches so as to open the lead wire of the motor. 4. The power transmission device according to claim 1, wherein the switching means is a relay. 5. The power transmission device according to claim 1, wherein the motor is a brush motor. 6. A one-way clutch is further provided at a rear stage or a front stage of the friction roller type transmission.
The power transmission device according to any one of 1. 7. The one-way clutch is provided at a rear stage of the friction roller type transmission, and the idling torque of the one-way clutch is lower than the idling torque of the friction roller type transmission. The power transmission device described. 8. The power transmission device according to claim 1, wherein an output shaft of the friction roller type transmission is connected to a crank shaft of a vehicle engine. 9. An automobile provided with the power transmission device according to claim 8. 10. The output shaft of the friction roller type transmission is
The power transmission device according to any one of claims 1 to 7, which is connected to a pedal shaft of a bicycle. 11. A bicycle equipped with the power transmission device according to claim 10. 12. A method of controlling a motor with a friction roller type transmission, wherein rotational power is transmitted from a shaft of the motor via a friction roller type transmission, wherein the friction roller type transmission is concentrically fixed to the shaft. And a center roller having an outer peripheral surface as a first cylindrical surface, an outer ring provided with an inner peripheral surface as a second cylindrical surface around the center roller so as to be rotatable relative to the center roller, and concentric with the outer ring. Fixed to the output shaft, three or more pivots arranged parallel to the central roller in an annular space between the first cylindrical surface and the second cylindrical surface, and rotatable by these respective pivots. A width of the annular space is provided by including three or more intermediate rollers that are supported and each have an outer peripheral surface as a third cylindrical surface, and eccentric the center of the center roller and the centers of the outer ring and the output shaft. Circumferential dimension A non-uniformity is made over the intermediate rollers, and at least one intermediate roller among the three or more intermediate rollers is supported as a movable roller so as to be slightly displaceable in the circumferential direction of the annular space, and the remaining intermediate rollers are guide rollers. The movable roller is configured to move toward the narrow width portion of the annular space when the central roller rotates in a predetermined direction. At least from the friction roller type transmission side to the motor side. A method for controlling a motor with a friction roller type transmission, characterized in that a lead wire of the motor is short-circuited when a torque for rotating the shaft acts.