JPS6028747A - Motor with brake - Google Patents

Abstract

PURPOSE:To generate a brake torque in a small-sized light-weight motor by integrating a permanent magnet and an electromagnet, and controlling to switch the energization of an electromagnet. CONSTITUTION:An exciting coil 27 is not energized when a motor is stopped, a brake disc 20 is attracted by a permanent magnet 23, and the outer periphery of the brake disc 20 is pressed to a frictional disc 26. An energizing coil 27 is energized by the coil 27 when the motor is rotated, a magnetic flux for cancelling the magnetic flux by the magnet 23 is generated, and the disc 20 is separated from the disc 26 by a recoiling spring 22. The magnetic fluxes of the magmet 23 and the coil 27 are added by altering the energizing polarity to the coil 27, and acted to the disc 22, a large contacting pressure is generated between the discs 22 and 26 to abruptly brake.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an electric motor with a brake.

Conventional configuration and its problems Conventional brake-equipped electric motors, as shown in Fig. 1, have a concrete configuration. The brake disc 2 is pulled apart by the force of a brake spring 3 and pressed against a friction disc 6 fixed to the motor shaft 4, thereby braking the motor shaft 4. Therefore, when the electric motor 6 is operating, the brake plate 2 must be attracted against the force of the brake spring 3. In the event of an emergency stop, etc., the necessary braking torque is extremely large, and the return force of the brake spring 3 that generates that torque is also large, and of course the excitation coil 1 that attracts the brake disc 2 against that force also needs to be applied. A large one is required and the shape/
This increases the weight, which is a serious drawback, especially when an electric motor with a brake is mounted on a moving part of a mechanical device.

OBJECTS OF THE INVENTION In view of the above-mentioned drawbacks of the conventional motor, the present invention provides a compact and lightweight electric motor with a brake.

Structure of the Invention The present invention uses a combination of a permanent magnet and an electromagnet, and when the motor is running, the magnetic flux with the permanent magnet is canceled out by energizing the excitation coil of the electromagnet, thereby releasing the brake disk with a return spring. During a normal stop, the magnetic flux of the permanent magnet attracts the brake disk and performs braking, and when sudden braking is required, such as during an emergency stop, the excitation coil is energized with the opposite polarity, thereby reducing the magnetic flux of the excitation coil and the permanent magnet. It is configured to generate a large braking torque by applying magnetic flux, and is designed to be smaller and lighter when generating the same braking torque.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a sectional view of a flat type electric motor with a brake according to an embodiment of the present invention.

In FIG. 2, the electric motor 7 includes an electric motor shaft 8, an armature 9,
It is composed of yokes 10, 11, permanent magnets 12, commutator 13, brush 14, brush spring 15, bearing 16, casing 17, etc., but the structure is universal and is not directly related to the present invention, so it will not be explained in detail. is omitted.On the motor shaft 8 on the opposite side from the motor 7, there is a magnetic material attached with a key 19 or a spline so that it can rotate with the shaft and be slidable in the axial direction. A brake disc 2Q consisting of the following is installed.

A return spring 22 is placed between the brake disc 20 and a collar 21 fixed on the motor shaft 8, and urges the brake disc 20 in a direction opposite to the attractive force of the permanent magnet 23. It is pressed against a stopper 24 fixed on the motor shaft 8. The permanent magnet 23 is formed in a double annular shape with a U-shaped cross section, and is placed on the casing 17 by a holder 26, concentrically with the motor shaft 8, and with a slight contact with the brake disc 20 when not attracted. They are fixed facing each other with a gap in between. The magnetic pole of the permanent magnet 23 is formed in the axial direction of the motor shaft 8, and in a normal state, the permanent magnet 23 moves the brake disc 2o towards the return spring 2.
It is adsorbed against the force of 2. In the adsorbed state, the outer periphery of the brake disc 2o is opposite to the holder 26.
It is pressed against a friction disk 26 fixed to the friction disk 26, and the frictional force with the friction disk 26 generates sufficient braking torque against the load.

Page 5 An annular excitation coil 27 is buried in a resin in the U-shaped recess of the permanent magnet 23, and is connected to a brake control circuit (not shown). The excitation coil 2 is arranged so that the magnetic flux when energized flows in the axial direction of the motor, similarly to the permanent magnet 23.

The operation of the electric motor with a brake configured as described above will be explained below.

When the electric motor is stopped, the excitation coil 27 is not energized by the brake control circuit, the brake disc 2o is attracted by the permanent magnet 23, and the outer periphery of the brake disc 2o is connected to the fixed friction disc. 26, and the frictional force of both forces generates braking torque against the load.

The braking torque in this case only needs to be large enough to withstand the torque due to the load when the vehicle is stationary.

When the motor is rotating, the brake control circuit energizes the excitation coil 27, causing the excitation coil 27 to generate a magnetic flux in a direction that cancels the magnetic flux produced by the permanent magnet 23, and whose magnitude is equal to the permanent magnet 23. magnet 2
If the magnetic fluxes are the same as those of No. 3, they cancel each other out and the attractive force disappears, and the brake disc 2o is separated from the friction disc 26 by the return spring 22, and the braking torque disappears.

When stopping the rotating electric motor, when the electric current of the electric motor is cut off and the electric current of the excitation coil 27 is cut off at the same time, the brake disc 22 is attracted by the permanent magnet 23 and comes into contact with the friction disc 26. It generates braking torque and gradually stops while absorbing the inertia of the load. When the rotating electric motor is to be stopped immediately, such as in the case of an emergency, the magnetic flux of the permanent magnet 23 and the magnetic flux of the exciting coil 27 are added by changing the polarity of the current to the exciting coil 27 using the brake control circuit. This acts on the brake disk 22 and generates a large contact pressure with the friction disk 26, resulting in rapid braking.

Furthermore, when the present invention is applied to a servo motor or the like to perform a stopping operation to a target position, page 7 shows that the brake control circuit controls the excitation coil 27.
It is possible to adjust the brake torque by changing the degree of energization, and it is possible to perform an optimal stopping operation.

Effects of the Invention As is clear from the above explanation, the present invention integrates a permanent magnet and an electromagnet, and when the motor is running, the polarity of the electromagnet and the permanent magnet is changed to cancel out each other's magnetic flux, producing a brake torque of 1o, and stopping the motor at a standstill. Sometimes the magnetic flux of a permanent magnet causes the brake disc υ
It generates braking torque by pressing it against the circular plate, and when it comes to a sudden stop, the polarity of the permanent magnets is the same to obtain a strong magnetic flux, and even larger braking torque can be generated, so the same braking torque can be generated. This has the effect of reducing the size and weight of the motor, making it particularly suitable for use as a brake-equipped electric motor mounted on moving parts of machinery and other parts where inertia needs to be reduced, and the effect of its industrial use has been fully recognized. FIG. 1 is a side sectional view showing the structure of a conventional electric motor with a brake, and FIG. 2 is a side sectional view showing an embodiment of the present invention.

2o...brake disc, 22...return spring, 23...permanent magnet, 26...friction disc, 27...excitation coil.

Claims (1)

[Claims] an electric motor, a double annular permanent magnet with a U-shaped cross section provided concentrically with the motor shaft of the electric motor, an annular excitation coil installed in a recess of the U-shaped cross section of the permanent magnet; a brake disc made of a magnetic material, which is attached to the motor shaft by a spline so that it rotates integrally with the shaft and is slidable in the axial direction, and is biased by a return spring in a direction opposite to the attractive force of the permanent magnet; An electric motor with a brake consists of this brake disc and a friction disc fixed opposite to it.