JPH0822139B2 - Electric motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to an electric motor that obtains a braking force by utilizing the magnetic action of a stator when the electric motor is turned on and off,
More specifically, the present invention relates to an electric motor that reduces a portion that rotates integrally with a rotor and restricts a modified portion of the electric motor body as much as possible to incorporate a braking mechanism having a braking force.

b. Conventional technology As a braking device for an electric motor, there are a mechanical braking method and an electric braking method.

As a mechanical braking method, a method of providing an electromagnetic brake is known. However, a device provided with such an electromagnetic brake requires a separate power source, and thus has drawbacks such as an increase in cost and an increase in size.

Therefore, there is known a prior art in which the magnetic force of the stator is used to obtain the braking force. (Jitsuko Sho 60-37016) This prior art will be explained with reference to FIG.
Is a casing, 101 is a stator core 102 and stator winding 10
It is a stator consisting of three. This stator 101 is a stator core 10
A fixed iron core 104 is integrally provided on one end face of 2
The stator winding 103 is commonly inserted in the winding insertion grooves 2 and 104. The base plate of the fixed iron core 104 is the stator iron core 1
It is formed by stacking thin plates made of the same material as the base plate of 02, and the inner peripheral end of each base plate is bent in the axial direction to form a cone-shaped magnetic pole surface 10.
Make up 5.

On the other hand, the rotary shaft 107 supporting the rotor 106 has a fixed iron core.
A movable iron core 109 having a magnetic pole surface 108 having a shape corresponding to the magnetic pole surface 105 of 104 is provided so as to be movable only in the axial direction. One end surface of the movable iron core 109 has a braking lining 1
A rotary braking plate 111 to which 10 is attached is provided, and a fixed braking surface 113 is formed on the inner surface of the motor bracket 112 facing the braking lining 110 of the rotary braking plate 111.
Reference numeral 114 denotes a pressing spring disposed between the movable iron core 109 and the rotor 106, which constantly presses the movable iron core 109 toward the motor bracket 112 side.

 The operation of the above prior art will be described.

When the stator winding 103 is excited when starting the electric motor,
A rotating magnetic field is generated, and a magnetic attraction force is generated between the fixed iron core 104 and the movable iron core 109. As a result, the movable iron core 109 is attracted to the fixed iron core 104 side against the elastic force of the pressing spring 114,
The braking lining 110 is separated from the fixed braking surface 113. The movable iron core 109 is locked by the step portion of the rotating shaft 107 and stops. Thus, the electric motor is in the operating state.

Next, when the power supply is cut off and the example magnetism of the stator winding 103 is released, the magnetic attraction force between the fixed iron core 104 and the movable iron core 109 disappears, and the biasing force of the pressing spring 114 acts to move the movable iron core 109.
Moves to the motor bracket 112 side. In this way, the braking lining 110 is pressed against the fixed braking surface 113, and the rotating shaft 107 is braked via the movable iron core 109.

c. Problem to be Solved by the Invention However, according to the above-described conventional braking device, when the stator 101 is molded, the stator core 102 and the stator core 104 that are separate bodies are formed.
In addition, since the conical magnetic pole surface is formed, and the tooth portion of the fixed iron core 104 needs to be bent while sequentially changing the diameter, the machining becomes complicated and the electric motor itself must be greatly improved. Further, since the fixed iron core 104 projects to the inner peripheral side of the fixed solid iron core 102, it is difficult to wind the stator winding 103. Further, since the movable iron core 109 and the pressing spring 114 rotate together with the rotating shaft 107, the rotating shaft 107 is more weighted and the movable iron core 109 and the pressing spring 114 are likely to be damaged. Furthermore, since there is a gap between the movable iron core 109 and the fixed iron core 104, the electromagnetic force due to the rotating magnetic field cannot be effectively used, and therefore the pressing spring 114
Since the pressing force of is limited, the braking force cannot be increased. Further, since the pressing spring 114 and the movable iron core 109 are mounted on the rotating shaft 107, there is a problem that the weight of the rotating shaft 107 increases.

The present invention solves the above-mentioned problems of the prior art, and provides an electric motor capable of reducing a portion that rotates integrally with a rotating shaft, suppressing a modified portion of an electric motor body as much as possible, and incorporating a braking mechanism having a braking force. The purpose is to

d. Means for Solving the Problems In order to solve the above problems, the present invention provides a stator 3 and a rotor 6 in a motor housing configured by a casing 1 and a motor bracket 2, The stator 3 is mounted via a rotary shaft 7 supported by a motor housing.
The stator 3 is rotatably supported on the inner axis of
In a motor for driving the rotor 6 to rotate by a rotating magnetic field generated in the motor 6, a disc-shaped brake plate 12 provided with a brake lining 13 facing the side surface of the rotor 6 is supported on the rotary shaft 7 and On the guide member 15
Mounted concentrically with the rotary shaft 7 and provided on the inner peripheral side of the protrusion 16 interposed between the rotor 6 and the brake plate 12,
Moreover, the cylindrical armature 14 having the friction surface 16a provided on the surface of the protrusion 16 facing the brake lining 13 is slidable on the guide member 15 in the same direction as the axial direction of the rotary shaft 7. Springs 17, 19 for urging the armature 14 so that the friction surface 16a contacts the brake lining 13 are mounted on the motor housing, and the inner peripheral surface of the stator 3 and the rotor 6 are A gap is provided between the outer peripheral surfaces so that the tip of the armature 14 can move in and out, and when the stator 3 is excited, the magnetic attraction of the stator 3 is used to move the tip of the armature 14 to The spring is pulled when the armature 14 is pulled away from the brake plate 12 by suction into the gap and the stator 3 is in the non-excited state.
Brake plate for armature 14 using the resilience of 17, 19
The reason is that it is pressed to the 12 side to obtain braking force.

e. Action When the stator 3 of the electric motor is excited, the attraction force of the stator 3 works, and the armature 14 moves to the side of the stator 3 against the repulsive force of the springs 17 and 19. Then, the friction surface 16a of the armature 14 is separated from the brake lining 13 of the brake plate 12. Thus, the rotary shaft 7 of the electric motor rotates.

Next, when the electric power to the stator 3 of the electric motor is cut off, the magnetic attraction force of the stator 3 disappears.
The armature 14 is pulled toward the brake 12 plate side by the elastic force of. Thus, the friction surface of the armature 14
16a presses against the brake lining 13 of the brake plate 12 to exert a braking action and stop the rotation of the rotary shaft 7. Since only the brake plate 12 is provided on the rotary shaft 7, the weight of the rotary shaft 7 does not increase. Further, since the stator 3 and the rotor 6 are used as they are, it is not necessary to remodel the electric motor itself.

f. Examples Hereinafter, the present invention will be described in detail with reference to the illustrated examples.

1 is a longitudinal sectional view showing an embodiment when the braking force of the electric motor according to the present invention is working, FIG. 2 is a partially enlarged sectional view when the electric motor of FIG. 1 is in a driving state, and FIG. 1 is a partially enlarged sectional view showing an armature tip portion in FIG. 1 in an enlarged manner, FIG. 4 is a vertical sectional side view showing another embodiment of the present invention, and FIG. 5 is a sectional view taken along the line AA in FIG. Is.

1 to 3, 1 is a casing, 2 is a motor bracket, and the casing 1 and the motor bracket 2 constitute a motor housing. Reference numeral 3 denotes a stator provided on the inner peripheral surface of the casing 1, which is composed of a stator core 4 and a stator winding 5. Reference numeral 6 denotes a rotor supported by a rotary shaft 7 which is rotatably supported on the inner axis of the stator 3, and is composed of a rotor core 8 and a rotor conductor 9.

The rotating shaft 7 is supported on the inner surfaces of the bosses 1a and 2a of the casing 1 and the bracket 2 via bearings 10 and 11, and a disc-shaped brake plate 12 is fixedly supported in the middle thereof. The brake plate 12 is arranged between the convex portion 7a of the rotary shaft 7 and the bearing 11, and this has a ring-shaped brake lining 13 mounted along the peripheral edge of the plate surface on the rotor 6 side so that the friction surface 13a. Is formed.

Reference numeral 14 denotes a cylindrical armature which is arranged on the inner end surface of the stator iron core 4 in a state of being abutted at a predetermined interval, and which is mounted concentrically with the rotating shaft 7 on the outer surface side of the boss portion 2a of the bracket 2. The guide member 15 is slidably supported in the same direction as the axial direction of the rotary shaft 7. The armature 14 is provided with a protrusion 16 projecting between the rotor 6 and the brake plate 12 on the inner peripheral side, and the protrusion 16 has a friction surface on a surface facing the friction surface 13a of the brake lining 13. Face 16a
Are formed.

17 is attached to the rear end of the armature 14 and is attached 1
One or a plurality of leaf springs, one end of which is engaged with a hole 14a formed in the rear end of the armature 14 and the other end of which is fixed to the bracket 2 through caulking pins or screws 18 or the like. .

As shown in FIG. 3, the armature 14 is formed in a stepped portion 14b with its tip end corresponding to the corner portion of the stator core 4. Between the inner peripheral surface of the stator 3 and a part of the outer peripheral surface of the rotor, a gap Q through which the tip portion 14c of the armature 14 moves in and out is formed. The gap Q may be formed by forming the step 9a on the facing surface of the rotor conductor 9 corresponding to the tip of the armature 14.

 Next, the operation of the above electric motor will be described.

When the electric motor is stopped, that is, when the stator 3 is not excited, the armature 14 is pulled toward the bracket 2 side by the elastic force of the leaf spring 17. The friction surface 16a of the armature 14 is the friction surface 1 of the brake lining 13.
The rotary shaft 7 is in a braking state by being pressed against the 3a (see FIG. 1).

When the power is turned on during the operation of the electric motor, the stator winding 5 is excited to generate a rotating magnetic field, and the stator core 4
Serves as a magnetic path that allows a part of the magnetic flux of the rotating magnetic field to pass through the gap Q, and a magnetic attraction force acts between the stator core 4 and the armature 14. As a result, the armature 14 is attracted toward the stator core 4 side against the elastic force of the leaf spring 17 and moves in the axial direction, and the armature 14 is stepped at the corner portion of the stator core 4 by the step portion 14b.
Are adsorbed (see FIG. 2). Thus the armature
By the movement of 14, the friction surface 16a is separated from the friction surface 13a of the brake lining 13, and the rotating shaft 7 becomes free. Then, the rotating magnetic field generated by the stator 3 causes the rotor 6 to start rotating and enter a driving state.

Next, FIGS. 4 and 5 show a pin spring 19 used as a spring instead of the leaf spring 17 of the embodiment shown in FIG.
The other parts have the same structure as in FIG.

That is, a pin hole 20 is formed in the outer peripheral surface of the armature 14, and the pin spring 19 is inserted into the pin hole 20. Both ends of the pin spring 19 are engaged with the inner peripheral surface of the bracket 2 by forming holes 26, for example.

The pin spring 19 is inserted at a position where the boss portion 2a of the bracket 2 is removed.

Also in this case, the armature 14 is attracted against the repulsive force of the pin spring 19 by the attraction force of the stator 3 and is attracted to the corner portion of the stator core 4 by the attraction force of the stator 3, and the friction surface 16a is brake lining. It moves away from the friction surface 13a of 13. As a result, the rotating shaft 7 is released from the braking state and starts rotating. On the other hand, when the excitation of the stator is released by cutting off the power supply, the elastic force of the pin spring 19 pulls the armature 14 back, and the friction surface 16a becomes the friction surface 1 of the brake lining 13.
It comes into pressure contact with 3a and becomes in a braking state.

g. Effects of the Invention As described above, according to the electric motor of the present invention, the disc-shaped brake plate 12 provided with the brake lining 13 facing the side surface of the rotor 6 is supported on the rotary shaft 7, and the motor The guide member 15 is mounted concentrically with the rotary shaft 7 in the housing, and the protrusion 16 interposed between the rotor 6 and the brake plate 12 is provided on the inner peripheral side. A tubular armature 14 provided with a friction surface 16a on the surface facing the brake lining 13 is disposed on the guide member 15 so as to be slidable in the same direction as the axial direction of the rotary shaft 7, and the friction surface Springs 17 and 19 for urging the armature 14 are attached to the motor housing so that 16a comes into contact with the brake lining 13, and between the inner peripheral surface of the stator 3 and the inner peripheral surface of the rotor 6, A space is provided to allow the tip of the armature 14 to move in and out, and When the stator 3 is excited, the tip end of the armature 14 is sucked into the gap by using the magnetic attraction force of the stator 3 to separate the armature 14 from the brake plate 12, and the stator. When 3 is in the non-excited state, the elastic force of the springs 17 and 19 is used to press the armature 14 toward the brake plate 12 to obtain the braking force. Since the braking mechanism can be assembled only by incorporating 12, the braking mechanism can be provided with a small number of parts and a slight improvement. Therefore, it is possible to provide an inexpensive and compact electric motor as compared with a motor in which a braking mechanism is mounted outside the electric motor.

Also, since only the brake plate 12 is attached to the rotary shaft 7, the rotary shaft 7 is not so heavily loaded.
The torque of the electric motor does not decrease.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing an embodiment when the braking force of an electric motor according to the present invention is working, and FIG. 2 is a case where the electric motor of FIG. 1 is driven. 3 is a partially enlarged sectional view of FIG.
FIG. 4 is a partially enlarged sectional view showing an armature tip portion in an enlarged manner, FIG. 4 is a vertical sectional view showing another embodiment of the present invention, and FIG.
The drawing is a sectional view taken along the line AA in FIG. 4, and FIG. 6 is a half sectional view showing a conventional electric motor. 1 ... Casing, 2 ... Motor bracket, 3 ... Stator, 6 ... Rotor, 7 ... Rotating shaft, 12 ... Brake plate, 13 ... Brake lining, 14 ... Armature, 14c ... Tip Part, 16 ... Projection, 16a ... Friction surface, 17 ... Leaf spring, 19 ... Pin spring.

Claims (1)

[Claims] 1. A stator 3 and a rotor 6 are provided in a motor housing composed of a casing 1 and a motor bracket 2, and the rotor 6 is mounted on a rotor shaft 7 supported by the motor housing. Of the rotor 6 that is rotatably supported on the inner axis of the rotor 3 and that drives the rotor 6 to rotate by the rotating magnetic field generated in the stator 3.
A disk-shaped brake plate 12 provided with a brake lining 13 facing the side surface of the rotor 6 is supported by the rotary shaft 7, and a guide member 15 is mounted in the motor housing concentrically with the rotary shaft 7, A cylindrical armature 14 provided on the inner peripheral side of the protrusion 16 interposed between the brake plate 12 and the brake plate 12, and having a friction surface 16a on the surface of the protrusion 16 facing the brake lining 13, The guide member 15 is slidably disposed in the same direction as the axial direction of the rotary shaft 7, and the friction surface
Springs 17 and 19 for urging the armature 14 are attached to the motor housing so that 16a comes into contact with the brake lining 13, and between the inner peripheral surface of the stator 3 and a part of the outer peripheral surface of the rotor 6. When a gap is provided in which the tip of the armature 14 moves in and out, and when the stator 3 is excited,
The magnetic attraction force of the stator 3 is used to attract the tip of the armature 14 into the gap to separate the armature 14 from the brake plate 12, and when the stator 3 is in the non-excited state, An electric motor characterized in that the armature 14 is pressed against the brake plate 12 side by using the elastic force of the springs 17 and 19 to obtain a braking force.