JPH06133496A - Motor containing torque limiter - Google Patents

Abstract

PURPOSE:To obtain a motor which contains a torque limiter in which setting of a control torque is easy, a problem such as a variation in the torque during operating is eliminated, and which has a long life and eliminates an increase in a mounting space. CONSTITUTION:A rotor 4 of a motor is journaled rotatably to a rotary shaft 5, a hysteresis member 1 is fixed to an end face of the rotor, and a permanent magnet 2 is fixed to the shaft 5 in such a manner that the magnet 2 is opposed to the member 1 via an air gap and a torque is transmitted from the rotor 4 to the shaft 5 by an electromagnetic torque operating between the member 1 and the magnet 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor having a built-in torque limiter, and more particularly to a motor having a built-in torque limiter composed of a permanent magnet and a member having an appropriate hysteresis coefficient.

[0002]

2. Description of the Related Art Conventionally, when a mechanical device is driven by a motor and the load torque of the mechanical device exceeds the rated torque of the motor, the motor may overheat or the load device may be damaged. This can happen, and if the degree exceeds a certain limit, it may cause a serious failure that damages the motor or load device. Therefore, conventionally, if a torque limiter is interposed between the motor and the load device and the load torque exceeds a certain limit, the torque limiter slips and the torque exceeding the limit is prevented from being transmitted. Measures have been taken to prevent damage to the motor and load device. FIG. 2 is an example in which a friction type torque limiter is provided on the output shaft of a conventional motor. Reference numeral 11 is a drive motor, 12 is a load device, and 13 is a friction type torque limiter. The torque limiter 13 connects the input side disk 13-1 to the output shaft 1 of the motor.
The output side disk 13-2 is fixed to the load side input shaft 12-1, and the friction member 13-3 is interposed between the input side disk 13-1 and the output side disk 13-2. Then, the spring 13-5 applies an axial pressure to the friction member 13-3 to generate a transmission torque between the input side disk 13-1 and the output side disk 13-2. If the torque transmitted from the motor 11 to the load device 12 is within the rated torque of the motor, for example, no slip occurs between the input side disk 13-1 and the output side disk 13-2, and the load device 12 is It rotates at the same speed as the motor 11.

However, if the torque of the load device 11 is the motor 1
In a situation where the torque limiter 13 exceeds the rated torque, even if an attempt is made to transmit the torque exceeding the limit torque of the torque limiter 13, the input side disk 13-1 and the output side disk 13-2 of the torque limiter 13 are separated from each other. A slippage occurs between them, the transmission torque is suppressed within the limit torque, and the load device continues to operate in a torque transmission state within the rated torque of the motor 11 to prevent overloading of the motor 11.

[0004]

However, in the torque limiter device according to the prior art as described above, a friction member is interposed between the disks on the input side and the output side, and a spring is provided between both disks. Since the structure is such that the value of the torque transmitted by applying pressure is set, there is a problem that the variation of the transmission torque is large due to wear and heat generation of the friction member, it is difficult to set the limiting torque, and the service life is short due to aging. Further, since the torque limiter 13 is provided outside the motor, an extra space is required when the motor is mounted, and therefore the device cannot be downsized.

[0006]

A motor incorporating a torque limiter according to the present invention rotatably supports a rotor around a rotary shaft, and a hysteresis member and a permanent magnet are provided between the rotor and the rotary shaft. Are opposed to each other through a gap, and one is fixed to the rotor and the other is fixed to the rotating shaft, and the torque of the rotor is transmitted to the rotating shaft by the electromagnetic force acting between the hysteresis member and the permanent magnet. To achieve the purpose.

[0007]

In the motor incorporating the torque limiter according to the present invention, the torque is transmitted between the rotor and the rotary shaft by the electromagnetic force acting between the hysteresis member and the permanent magnet. It is easy to perform, the transmission torque is stable, and since it is provided inside the motor close to the rotor, there is an effect that the mounting space of the motor can be reduced.

[0008]

1 is a cross-sectional view showing a motor incorporating a torque limiter according to the present invention, showing an example of an induction motor, in which 1 is a hysteresis member, 2 is a permanent magnet, 3 is a yoke of a permanent magnet, 4 is a rotor, 5 is a rotating shaft, 6 is a bearing that rotatably supports the rotor with respect to the rotating shaft, 7 is a case of a motor stator, 8 is a stator, and 9 is a gap between a hysteresis member and a permanent magnet. Reference numeral 10 is a bearing that supports the rotating shaft.

In a motor having a built-in torque limiter shown in FIG. 1, a stator 8 is provided inside a stator case 7, and a rotating shaft 5 is rotatably supported by bearings 10 provided in front of and behind the stator case 7. Then, the rotor 4 is rotatably supported by the bearing 6 with respect to the rotary shaft 5, the hysteresis member 1 is fixed to one end surface of the rotor 1, and the yoke 3 with which the permanent magnet 2 is abutted is fixed to the rotary shaft 5. The permanent magnet 2 and the hysteresis member 1 are fixed so as to face each other with a gap 9 therebetween.

The end surface of the permanent magnet 2 is appropriately magnetized so that the magnetic flux of the permanent magnet 2 circulates between the opposing hysteresis member 1 through the air gap 9.

When the motor rotates, an attractive force acts between the rotor 4 and the rotating shaft 5 due to the interaction between the permanent magnet 2 and the hysteresis member 1 and the magnetic pole that is generated due to a delay in the change due to the hysteresis characteristic. The shaft 5 rotates at the same speed as the rotor 4 and transmits power to a load device connected to the rotating shaft 5.

The attractive force acting between the rotor 4 and the rotary shaft 5 is determined by the magnetic flux of the permanent magnet 2, the hysteresis coefficient of the hysteresis member 1 and the electromagnetic force determined by the gap 9 between the permanent magnet 2. Therefore, the limiting torque can be determined by adjusting the size of the gap 9 between the two. Motor rotation shaft 5
When the load torque applied to the motor exceeds the limit torque, the rotating shaft 5 cannot follow the rotor 4 and slips, thereby preventing the motor from being overloaded.

In the embodiment of the present invention shown in FIG. 1, the hysteresis member 1 is fixed to the end face of the rotor 4 of the motor, and the permanent magnet 2 is fixed to the rotary shaft 5, respectively. The same effect can be obtained by a structure in which 1 is fixed to the rotary shaft 5 and the permanent magnet 2 is fixed to the end surface of the rotor 4. or,
Although the embodiment shown in FIG. 1 shows the structure in which the torque limiter is provided inside the induction motor, it goes without saying that the same effect can be obtained even if the motor is a DC motor.

[0014]

The motor having a built-in torque limiter according to the present invention has the above-described structure, and the torque is transmitted from the rotor to the rotary shaft by the electromagnetic force acting between the rotor and the rotary shaft. The limiting torque can be easily set and the limiting torque is stable over a long period of time, and the torque limiter is built into the motor, so that the mounting space of the motor can be small.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a motor incorporating a torque limiter according to the present invention.

FIG. 2 is an explanatory diagram of a configuration in which a friction type torque limiter according to a conventional technique is provided between a motor and a load device.

[Explanation of symbols]

 1: Hysteresis member 2: Permanent magnet 3: Permanent magnet yoke 4: Rotor 5: Rotating shaft 6: Bearing that rotatably supports the rotor on the rotating shaft 7: Stator case 8: Stator 9: Hysteresis member Between the magnet and the permanent magnet 10: Bearing that rotatably supports the rotating shaft 11: Drive motor 12: Load device 13: Friction torque limiter 13-1: Input side disk 13-2: Output side disk 13-3: Friction Member 13-4: Spring stopper 13-5: Spring

Claims (4)

[Claims] 1. A motor having a structure in which power is taken out from a stator having a winding wound around it and a rotary shaft of the rotor that is rotatably supported facing the stator via a gap and rotates the rotor. A hysteresis member made of a semi-hard magnet material is provided on the end surface of the rotor so as to be slidable with respect to the shaft, and a permanent magnet is fixed to the rotor shaft together with a yoke made of a magnetic material. A motor with a built-in torque limiter, which is arranged so as to face each other with a gap. 2. A rotor having a structure in which power is taken out from a stator around which a winding is wound and a rotary shaft of the rotor that is rotatably supported facing the stator through a gap. A rotor is slidably supported on a shaft, a permanent magnet is fixed to the end face of the rotor together with a magnetic yoke, a hysteresis member made of a semi-hard magnet material is fixed to the rotor shaft, and the hysteresis member is fixed to the permanent magnet. A motor having a built-in torque limiter, which is arranged so as to face each other with a gap. 3. The motor incorporating the torque limiter according to claim 1, wherein the motor is an induction motor. 4. The motor incorporating the torque limiter according to claim 1, wherein the motor is a DC motor.