JPH09308187A - Motor with brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure an installation place for a brake which produces torque opposite to the direction of revolution of a motor and brakes it and to make setting work unnecessary. SOLUTION: A drum 15 for forming an induced current circuit fixed to a shaft 7 and a supporting frame 19 fixed to a housing 1 are arranged coaxially to the shaft 7, and are put in the housing 1. The stator 11 the rotor 12 of a motor are fixed to the housing 1 and the drum 15. A plurality of pole shoes 17 having magnetic pole generating exciting coils 16 are arranged inside the drum 15, and fitted to the supporting frame 19 radially. A direct current is caused to flow in the exciting coils and magnetic fluxes and eddy currents are generated inside the drum 15, and by their interaction torque having a direction opposite to that of the rovolution of the drum 15 i.e., the revolution of the motor is generated and is caused to act as a braking force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor integrally provided with a braking device, and more specifically, to an electric motor having a braking device built into a housing.

[0002]

2. Description of the Related Art It is well known to use a mechanical or electric braking means to brake an electric motor when the motor is to be stopped rapidly, or when a heavy load is lowered at a safe speed by an electric motor driven hoist. .

Of these, the electric braking means is advantageous in terms of maintenance as compared with the mechanical braking means because it has no frictional portion, and it is easy to maintain a constant speed without stopping the cable. It is also well known that it is widely used for safety when lowering heavy objects in cars and hoisting machines in mines.

Regenerative braking, dynamic braking, anti-phase braking, and single-phase braking are known as electric braking means, but one of the anti-phase braking is used when a hoisting machine lowers a heavy object at a low speed. Inductive braking is often used.

FIG. 2 shows a hoisting machine utilizing an induction braking method for generating a rotating magnetic field in a direction opposite to that of an electric motor.
The electric motor 52 and the brake 53 are arranged in a line and connected to each other by a joint. FIG. 3 shows an example of a brake 53 conventionally provided for practical use, in which a drum 56 for forming an induction current circuit is fixed to a shaft 55 rotatably installed in the center of a housing 54, and an exciting coil 57 is provided. A magnetic pole piece 58 wound with is fixed to the housing 54 and arranged inside the drum 56.

When a direct current is passed through the exciting coil 57, the radially arranged magnetic pole pieces 58 are alternately magnetized to N and S in the circumferential direction, and the magnetic flux is linked to the drum 56. When the shaft 55 connected to the electric motor rotates, the magnetic flux changes, and an eddy current is generated inside the drum 56 by the power generation action. The torque generated by this eddy current acts as a braking force because it is opposite to the rotating direction of the drum 56, that is, the rotating direction of the electric motor, and this braking torque can be arbitrarily controlled by the direct current.

[0007]

The conventional hoisting machine with a brake has a structure in which a hoisting machine in which a winding cylinder and an electric motor are arranged in series is further arranged in series with a braking machine, and the overall length is considerably long. Therefore, not only does it require a large installation space, but the hem of the brake is cumbersome because the brake shaft is concentric with the hoist shaft.

The present invention requires the above-mentioned problem caused by connecting a brake having a structure for applying a braking force to the electric motor in a direction opposite to its rotation, in series with the electric motor, that is, it requires a large installation space.
This was done to solve the problem that the hem of the brake is troublesome.

[0009]

That is, according to the present invention, a drum for forming an induced current circuit is fixed to a shaft of an electric motor, a rotor is fixed to the outer side of the drum, and a magnetic pole piece having a magnetic flux generating exciting coil is provided in a housing. It is fixed to the inside of the drum, that is, the braking device is built in the housing of the electric motor. It is possible to eliminate the hem work.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The stator of an electric motor is mounted on the inner peripheral surface of a stator frame of a housing just like a normal electric motor, but the rotor is mounted on the outer peripheral surface of a drum of a braking device. The drum is preferably concentrically and cantileveredly fixed to the shaft of the electric motor by a plate-shaped or arm-shaped bracket provided at one end of the drum, and in this case, the magnetic pole piece having the exciting coil is opposite to the bracket. It is easy to load the inside of the drum from the open end of the side. It is advantageous in terms of assembly that the pole pieces are fixed to one bracket bearing of the housing and attached to the outer peripheral surface of a cylindrical support frame arranged concentrically with the shaft.

The stator and the rotor, the drum and the magnetic pole pieces, the support frame and the shaft are arranged concentrically with a proper circumferential clearance, and the shaft is freely rotatable in bracket bearings on both sides of the housing. In general, the housing bearing has a vent for heat dissipation, and the shaft has ventilation blades.

The present invention also provides a DC motor, a synchronous motor,
Although it can be applied to any of the induction motors, the speed control can be performed easily and appropriately when applied to a winding type or high resistance type electric motor, particularly a three-phase induction motor.
According to the present invention, when a three-phase induction motor with a built-in braking device is used as a hoist to lower a heavy object, regenerative braking that operates as an induction generator is performed at synchronous speeds or higher, and braking is performed at low speeds. It is possible to carry out the well-known braking operation in which the braking means is changed in response to the speed at which induction braking is performed by the device.

Further, when the braking device is built in as in the present invention, the housing has a large diameter instead of the total length, but it is only about one frame larger than an ordinary electric motor, so that the installation is restricted in place. I rarely get it.

[0014]

1 is a cross-sectional view showing an example in which the present invention is applied to a three-phase induction motor, and a housing 1 comprising a cylindrical stator frame 2 and bracket bearings 3 and 5 bolted to both ends thereof. The shaft 7 passing through the center of the bracket bearing 3.
5 is rotatably supported by bearings 4 and 6. One of the protruding ends of the shaft 7 has a key 8 that is coupled to a winding cylinder, which is a load, and the other protruding end has a DC rotation. A generator 9 is connected.

A stator 11 composed of an iron core and windings is attached to the inner peripheral surface of the stator frame 2, and a rotor 12 composed of a laminated iron core and windings is arranged inside the stator 11. ing.

On the other hand, a cylindrical drum 15 made of a magnetic material for forming an induction current circuit is fixed to a bracket 14 whose one end is fixed to the shaft 7 so as to be concentrically and cantilevered to the shaft 7. It is arranged between the shaft 7 and the stator 11. The rotor 12 is fixed to the outer peripheral surface of the drum 15, and functions as a normal induction motor that rotates the shaft 7 by the moving magnetic field of the stator 11.

The bracket 14 has a structure in which a plurality of plate-like arms are radially provided on a boss fitted to the shaft 7 so that air can freely flow.

Next, a cylindrical support frame 19 is installed between the shaft 7 and the drum 15 concentrically with the shaft 7 with a slight clearance. The support frame 19 is a bracket bearing. 5
Is fixed in a cantilever manner by bolt connection to the bracket 14 and is inserted from the open end opposite to the bracket 14.

The exciting coil 16 is provided on the outer peripheral surface of the support frame 19.
A plurality of magnetic pole pieces 17 each having a circle are radially attached at equal intervals in the circumferential direction, and the magnetic pole pieces 17 have a narrow gap with the drum 15.

Further, the bracket 14 and the bracket bearing 3
Ventilation blades 20 attached to the shaft 7 are provided in the space between and, and ventilation holes 21 are provided in the bracket bearing 5 on the opposite side to prevent overheating of the interior of the housing 1 due to heat generation. .

The drum 15, the exciting coil 16 and the magnetic pole piece 17 constitute a braking device 18. When no direct current is applied to the exciting coil 16, the drum 15 functions as a normal three-phase induction motor, and a load connected to the shaft 7 is applied. To drive.

When a direct current is passed through the exciting coil 16, the radially arranged magnetic pole pieces 17 are magnetized in the circumferential directions N and S, and the magnetic flux is linked to the drum 15. When the electric motor is running, The eddy current is generated inside the drum 15 to generate the torque in the direction opposite to the rotating direction of the drum 15, as described above. This torque acts as a braking force because it is opposite to the rotating direction of the electric motor, and the braking torque can be arbitrarily controlled by changing the direct current for excitation.

Therefore, when a heavy load is unwound by the hoist, it is possible to prevent the heavy load from rotating at a high speed by rotating the shaft 7 and to wind the heavy load while maintaining a safe low speed.

[0024]

As described above, according to the present invention, the braking device for generating and braking the torque in the opposite direction to the rotation of the electric motor is built in, and the rotor is fixed to the drum forming the induced current circuit for braking. In addition, it is possible to install an electric motor that has a braking function and can safely handle loads in places where there is no room, because the place and hem work required for installing a separate brake are unnecessary. Is.

Further, since it is not necessary to separately handle the brake, there is an advantage that storage and transportation are easy.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of installation of a conventional electric motor with a brake.

3 is a vertical cross-sectional view of the brake of FIG.

[Explanation of symbols]

1 housing, 2 stator frames, 7 axes, 11 stators, 12 rotors, 15 drums, 16 example magnetic coils, 17 magnetic pole pieces, 18
Braking device, 19 support frame

Claims (1)

[Claims] 1. A drum for forming an induced current circuit fixed to the shaft and a support frame fixed to the housing are concentrically arranged and built in the shaft in a housing rotatably supporting the shaft. The stator and rotor of the electric motor are fixed to the inner peripheral surface of the stator frame of the housing and the outer peripheral surface of the drum, respectively, and a plurality of magnetic pole pieces having magnetic pole generating excitation coils are provided. An electric motor with a braking device, which is located inside the drum and radially mounted on an outer peripheral surface of the support frame.