Motor brake

Abstract

The motor brake (3) comprises: a fixed-side engaging plate (30) fixed to the motor shaft (4); a movable-side engaging plate (20) coaxially opposed to the fixed-side engaging plate (30) along the direction of the central axis (3a); and a self-holding solenoid (10) that causes the movable-side engaging plate (20) to move along the direction of the central axis to a stop release position (20A) separated from the fixed-side engaging plate (30) and a stop position (20B) engaged with the fixed-side engaging plate (30). When the motor stops, the solenoid (10) is driven to move the movable-side engaging plate (20) from the stop release position (20A) toward the stop position (20B). The movable-side engaging plate (20) reaching the stop position (20B) mechanically engages with the fixed-side engaging plate (30), forcibly stopping the motor shaft (4).

Description

Technical Field

[0001] This invention relates to a motor brake for stopping the motor shaft in emergency situations. Background Technology

[0002] Industrial motor brakes generally employ non-excitation electromagnetic brakes. When the brake is released, energizing the electromagnetic brake attracts the friction plate along the axial direction. In an emergency, stopping the energization of the electromagnetic brake allows the motor to stop using spring force and the friction of the friction plate. For example, patent document 1 describes a non-excitation electromagnetic brake.

[0003] Here, as a solenoid, a self-holding solenoid incorporating a permanent magnet is known for use with an open-frame solenoid. A plug-in iron core is attracted by a momentary energization of the coil, and after attraction, the plug-in iron core is held in place by the permanent magnet. This eliminates the need for energizing the plug-in iron core while it is in the attracted position, which is effective when extending battery life or reducing heat generation is desired. For example, Patent Document 2 describes the use of a self-holding solenoid as a hub motor for a parking brake.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2005-69391

[0007] Patent Document 2: Japanese Patent Application Publication No. 2013-56573 Summary of the Invention

[0008] Regarding brakes for motors without excitation, when the motor is running, the coil is energized, causing the friction plate to rotate freely under the magnetic attraction of the coil, overcoming the spring force. Wear particles from this free-rotation are generated on the friction plate. These particles are scattered towards the encoder disk located near the motor brake, causing encoder reading abnormalities. Additionally, oil mist or other oily substances sometimes adhere to the friction plate. This oil does not evaporate but remains on the friction plate, causing slippage during brake operation and preventing the motor from stopping in an emergency. Furthermore, the brake's stopping characteristics depend on the friction coefficient of the friction plate and the spring characteristics. Generally, a brake design tailored to the characteristics of each motor is required to generate braking force exceeding the motor's rated torque.

[0009] In view of this, the object of the present invention is to provide a motor brake that can reliably stop the motor in an emergency without using a friction plate and with low power consumption.

[0010] To solve the above-mentioned problems, the motor brake of the present invention is characterized by comprising:

[0011] A fixed side locking plate is integrally rotated with the motor shaft and is mounted on the motor shaft in a manner that does not move in the direction of the central axis;

[0012] A movable side locking plate, coaxially opposed to the fixed side locking plate in the direction of the central axis, is movable in the direction of the central axis but cannot rotate about the central axis; and

[0013] A solenoid that allows the movable side engaging plate to move along the central axis towards a stop release position separating it from the fixed side engaging plate and a stop position engaging it with the fixed side engaging plate.

[0014] One of the movable side locking plate and the fixed side locking plate has locking protrusions that protrude radially and are formed at equal angular intervals on the same circle centered on the central axis.

[0015] The other of the movable side locking plate and the fixed side locking plate has a locking recess formed in the radial direction at a position opposite to each of the locking protrusions in the direction from the central axis. The recessed end of the locking recess on the locking protrusion side opens in a manner that allows the locking protrusion to be inserted from the direction of the central axis.

[0016] In the stopped-released position of the movable-side locking plate, the locking protrusion disengages from the locking recess, and the fixed-side locking plate and the movable-side locking plate can rotate freely relative to each other.

[0017] At the stop position of the movable side locking plate, the locking protrusion is inserted into the locking recess, and the fixed side locking plate and the movable side locking plate are in a locking state where they cannot rotate relative to each other.

[0018] Under normal motor operation, the movable side engaging plate is in a stop-release position, separated from the fixed side engaging plate mounted on the motor shaft along the central axis. When the motor stops, the solenoid is driven, causing the movable side engaging plate to move from the stop-release position to the stop position. Upon reaching the stop position, the movable side engaging plate is mechanically engaged relative to the fixed side engaging plate, preventing relative rotation. That is, the engaging protrusions are forcibly inserted into the engaging recesses from the central axis, forming a mechanical engagement between them. Since the movable side engaging plate is a component that remains in a non-rotatable state, if the movable side engaging plate engages with the fixed side engaging plate on the motor shaft side, the motor shaft is forcibly stopped. If the solenoid is driven, causing the movable side engaging plate to return from the stop position to the stop-release position, the mechanical engagement between the fixed side engaging plate and the movable side engaging plate is released, and the motor shaft with the fixed side engaging plate is restored to a rotatable state.

[0019] It can eliminate the drawbacks caused by wear debris and friction plate slippage when the motor shaft is forcibly stopped using the friction force of the friction plate. In addition, compared with motor brakes that use friction plates, where the friction coefficient and spring force of the friction plate are set in a way that is suitable for each motor, the motor shaft is stopped by mechanical engagement, thus making the brake design easier.

[0020] Furthermore, regarding the motor brake of the present invention, a self-holding solenoid can be used as the solenoid. With a self-holding solenoid, energization is only required when the movable side engaging plate moves, eliminating the need for energizing the movable side engaging plate in both the stop-release and stop positions. Therefore, a motor brake with lower power consumption can be provided. Attached Figure Description

[0021] Figure 1 This is a schematic structural diagram showing a motor system equipped with the brake for a motor according to the present invention.

[0022] Figure 2 (A) is shown Figure 1 A diagram illustrating the operating state of a motor with a brake. Figure 2 (B) is an explanatory diagram showing the state of the motor when it is stopped.

[0023] Figure 3 (A) is an explanatory diagram showing the insert-type iron core side-locking circular plate as a movable side-locking plate. Figure 3 (B) is an explanatory diagram showing the motor shaft side engaging circular plate as a fixed-side engaging plate. Figure 3 (C) is a longitudinal sectional view showing the disengaged state of the motor during operation. Figure 3 (D) is a longitudinal sectional view showing the engaged state when the motor stops. Figure 3 (E) is an explanatory diagram showing the engagement state when the motor stops.

[0024] Figure 4 This is a schematic cross-sectional perspective view showing the structure of a self-holding solenoid for a motor brake. Detailed Implementation

[0025] Hereinafter, embodiments of the motor brake to which the present invention is applied will be described with reference to the accompanying drawings. Furthermore, the following embodiments illustrate one example of the present invention and are not intended to limit the invention to these embodiments.

[0026] Figure 1This is a schematic structural diagram showing the electric motor according to the embodiment. The electric motor 1 includes: a motor body 2; and a motor brake 3, which is mounted at the rear end of the motor body 2. The motor body 2 is a general electric motor, therefore, its internal structure is not shown in the diagram. The front end 4a of the motor shaft 4 of the motor body 2 protrudes forward from the front end of the cylindrical motor housing 5, and is connected to a load-side component (not shown). The rear end 4b of the motor shaft 4 passes through the rear end plate portion 5b of the motor housing 5 and protrudes rearward. A cup-shaped cover 6 for the motor brake 3 is fastened to the rear side of the motor housing 5. Inside the cover 6, the motor brake 3 is mounted on the end 4b of the motor shaft 4. A wiring cable 7 is led out from the motor brake 3 to the outside.

[0027] Figure 2 (A) is an explanatory diagram showing the state of the motor brake 3 when the motor is running. Figure 2 (B) is an explanatory diagram showing the state when the motor is stopped. The motor brake 3 includes: a solenoid 10; a movable side engagement plate 20, which is mounted on the front end of the insert-type iron core 11 of the solenoid 10; and a fixed side engagement plate 30, which is mounted on the shaft end 4b of the motor shaft 4.

[0028] The fixed-side locking plate 30 is formed into a circular plate shape of a specified thickness, rotates integrally with the motor shaft 4, and is coaxially fixed to the motor shaft 4 in a manner that does not move in the direction of the central axis 3a. The movable-side locking plate 20 is also formed into a circular plate shape, and is coaxially connected and fixed to the front end of the insert-type iron core 11 of the solenoid 10 in a manner that is coaxially opposite to the fixed-side locking plate 30 in the direction of the central axis 3a.

[0029] If the solenoid 10 is energized, the insert-type iron core 11 moves linearly along the central axis 3a with a specified stroke (e.g., 2-3 mm). When the insert-type iron core 11 is in... Figure 2 In the pulled-in position 11A shown in (A), the movable side engaging plate 20 fixed to its front end is in the stop release position 20A, separated from the fixed side engaging plate 30 by a certain gap in the direction of the central axis 3a. When the insert-type iron core 11 is in... Figure 2 In the state of the protruding position 11B shown in (B), the movable side engaging plate 20 fixed to its front end is in a stop position 20B that is mechanically engaged with the fixed side engaging plate 30. If the movable side engaging plate 20 is positioned in the stop position 20B, the fixed side engaging plate 30 becomes unable to rotate, and the rotation of the motor shaft 4 connected to it stops.

[0030] Figure 3 (A) is an explanatory diagram showing the movable side locking plate. Figure 3(B) is an explanatory diagram showing the fixed-side locking plate. Figure 3 (C) is a longitudinal sectional view showing the disengaged state of the motor during operation. Figure 3 (D) is a longitudinal sectional view showing the engaged state when the motor stops. Figure 3 (E) is an explanatory diagram showing the engagement state when the motor is stopped. The construction and engagement state of the movable side engagement plate 20 and the fixed side engagement plate 30 will be explained with reference to these figures.

[0031] The movable side engaging plate 20 has a plurality of outer peripheral engaging protrusions 21 and a plurality of inner peripheral engaging protrusions 22. The outer peripheral engaging protrusions 21 are arc-shaped protrusions of a certain thickness that are arranged at equal angular intervals on the same circle centered on the central axis 3a and protrude outward in the radial direction. The inner peripheral engaging protrusions 22 are also arc-shaped protrusions of a certain thickness that are arranged at equal angular intervals on the same circle centered on the central axis 3a and protrude inward in the radial direction.

[0032] The fixed-side engaging plate 30 has a plurality of outer peripheral engaging recesses 31 and a plurality of inner peripheral engaging recesses 32. The outer peripheral engaging recesses 31 are respectively positioned opposite to each outer peripheral engaging protrusion 21 in the direction from the central axis 3a. Each outer peripheral engaging recess 31 is an arc-shaped recess of a certain depth recessed outward in the radial direction, and is formed in a shape complementary to the outer peripheral engaging protrusion 21. Furthermore, the recessed end of the outer peripheral engaging recess 31 on the side of the outer peripheral engaging protrusion 21 is opened in a manner that allows the outer peripheral engaging protrusion 21 to be inserted in the direction from the central axis 3a.

[0033] Similarly, the inner peripheral engagement recesses 32 are respectively disposed opposite to each inner peripheral engagement protrusion 22 in the direction from the central axis 3a. The inner peripheral engagement recess 32 is an arc-shaped recess of a certain depth recessed in the radial direction, and is formed in a shape complementary to the inner peripheral engagement protrusion 22. In addition, the recessed end of the inner peripheral engagement recess 32 on the side of the inner peripheral engagement protrusion 22 is opened in a manner that allows the inner peripheral engagement protrusion 22 to be inserted in the direction from the central axis 3a.

[0034] More specifically, a movable side end face 23 in the movable side engaging plate 20 is formed opposite to the fixed side engaging plate 30. A circular annular protrusion 24 is formed coaxially on this movable side end face 23. The circular annular protrusion 24 protrudes from the movable side end face 23 in the direction of the central axis 3a with a certain thickness and a certain amount. The circular outer peripheral surface 25 of the circular protrusion 24 is smaller than the circular outer peripheral surface 23a of the movable side end face 23, and its circular inner peripheral surface 26 is larger than the circular inner peripheral surface 23b of the movable side end face 23. Outer peripheral engaging protrusions 21 are formed on the circular outer peripheral surface 25 of the circular protrusion 24 at first angular intervals along the circumferential direction. In addition, inner peripheral engaging protrusions 22 are formed on the circular inner peripheral surface 26 at second angular intervals along the circumferential direction. In addition, the front end portion of the annular protrusion 24 of the movable side locking plate 20 in the direction of the central axis is an annular front end portion 24a that protrudes toward the fixed side locking plate 30 from the outer peripheral side locking protrusion 21 and the inner peripheral side locking protrusion 22.

[0035] A circular fixed-side end face 33 is formed on the fixed-side engaging plate 30, which faces the movable-side end face 23 of the movable-side engaging plate 20. An annular groove 34 of a certain width and depth is formed coaxially on this fixed-side end face 33. The annular protrusion 24 of the movable-side engaging plate 20 can be inserted into the annular groove 34 from the direction of the central axis 3a. Regarding the annular groove 34, an outer peripheral engaging recess 31 is formed on the circular inner peripheral surface 35, which is its outer peripheral side, at a first angular interval along the circumferential direction. Furthermore, an inner peripheral engaging recess 32 is formed on the circular outer peripheral surface 36, which is the inner peripheral side of the annular groove 34, at a second angular interval along the circumferential direction.

[0036] The groove depth (groove depth in the direction of the central axis 3a) of the annular groove 34 is the same as the protrusion amount (protrusion amount in the direction of the central axis 3a) of the annular protrusion 24 of the movable side locking plate 20. If the annular protrusion is inserted into the annular groove 34, the annular front end face 27 of the annular protrusion 24 abuts against the groove bottom surface 37 in the direction of the central axis 3a, forming a state in which the fixed side end face 33 abuts against the movable side end face 23.

[0037] In the stop release position 20A of the movable side locking plate 20, as Figure 3As shown in (C), only the annular front end 24a of the annular protrusion 24 of the movable side engaging plate 20 is inserted into the annular groove 34 of the fixed side engaging plate 30 with clearance. In this state, both the outer peripheral engaging protrusion 21 and the inner peripheral engaging protrusion 22 are disengaged from the outer peripheral engaging recess 31 and the inner peripheral engaging recess 32 of the fixed side engaging plate 30. Therefore, the fixed side engaging plate 30 and the movable side engaging plate 20 are in a state of relative rotational freedom, and the motor shaft 4 is in a state of rotational freedom.

[0038] At the stop position 20B of the movable side locking plate 20, as Figure 3 As shown in (D) and (E), the outer peripheral engaging protrusion 21 and the inner peripheral engaging protrusion 22 are respectively inserted into the outer peripheral engaging recess 31 and the inner peripheral engaging recess 32, and the fixed side engaging plate 30 and the movable side engaging plate 20 are in an engaged state where they cannot rotate relative to each other. The movable side engaging plate 20 remains in a state where it cannot rotate around the central axis. Therefore, a rotation-stopping force is applied to the motor shaft 4, which is fixed to the fixed side engaging plate 30 that engages with the movable side engaging plate 20, thus forming a rotation-stopped state of the motor shaft 4.

[0039] Next, refer to Figure 4 The solenoid 10 that causes the movable side locking plate 20 to move to the stop release position 20A and the stop position 20B will be described.

[0040] The solenoid 10 is a self-holding solenoid. The solenoid 10 has a cylindrical frame 12. A hollow insert-type iron core 11 is configured to pass through the center of the frame 12. The insert-type iron core 11 is supported by the frame 12 and is able to move in the direction of the central axis 3a but cannot rotate. Inside the frame 12, a magnetic circuit including a coil 13 is formed to surround the insert-type iron core 11. This coil 13 generates an electromagnetic force for moving the insert-type iron core 11 towards the central axis 3a to a pull-in position 11A and a protruding position 11B. Additionally, a permanent magnet 14 is arranged inside the frame 12 to surround the insert-type iron core 11. This permanent magnet 14 generates an attractive force for holding the insert-type iron core 11 in its respective position (pull-in and protruding).

[0041] The movable side engaging plate 20 is coaxially fixed to the front end 11a of the insert-type iron core 11. When the insert-type iron core 11 is in the pulled-in position 11A, the movable side engaging plate 20 is positioned in the stop-release position 20A. If the insert-type iron core 11 moves to the protruding position 11B, the movable side engaging plate 20 is positioned in the stop position 20B.

Claims

1. A motor brake characterized by comprising: a fixed-side engaging plate that rotates integrally with a motor shaft of a control target and is attached to the motor shaft so as to move in a direction that is not a central axis direction; a movable-side engaging plate that is coaxial with the fixed-side engaging plate in the central axis direction; and a solenoid that moves the movable-side engaging plate in the central axis direction to a stop release position where the movable-side engaging plate is separated from the fixed-side engaging plate and a stop position where the movable-side engaging plate engages with the fixed-side engaging plate, the movable-side engaging plate comprising: a movable-side end surface that opposes the fixed-side engaging plate; a circular ring-shaped protruding portion that protrudes from the movable-side end surface in the central axis direction; a plurality of outer peripheral-side engaging convex portions that are formed at first angle intervals along a circular outer peripheral surface of the circular ring-shaped protruding portion and protrude in an outer radial direction in an arc shape; and a plurality of inner peripheral-side engaging convex portions that are formed at second angle intervals along a circular inner peripheral surface of the circular ring-shaped protruding portion and protrude in an inner radial direction in an arc shape, the fixed-side engaging plate comprising: a fixed-side end surface that opposes the movable-side end surface; a circular ring-shaped groove portion that is formed in the fixed-side end surface and allows the circular ring-shaped protruding portion to be inserted from the central axis direction; a plurality of outer peripheral-side engaging concave portions that are formed at the first angle intervals along the circular inner peripheral surface of the groove side surface on an outer peripheral side of the circular ring-shaped groove portion; and a plurality of inner peripheral-side engaging concave portions that are formed at the second angle intervals along the circular outer peripheral surface of the groove side surface on an inner peripheral side of the circular ring-shaped groove portion, a concave portion end on a side of the outer peripheral-side engaging convex portion of the outer peripheral-side engaging concave portion is open in a manner that allows the outer peripheral-side engaging convex portion to be inserted from the central axis direction, a concave portion end on a side of the inner peripheral-side engaging convex portion of the inner peripheral-side engaging concave portion is open in a manner that allows the inner peripheral-side engaging convex portion to be inserted from the central axis direction, the circular ring-shaped protruding portion of the movable-side engaging plate comprises a circular ring-shaped front end portion that protrudes toward the fixed-side engaging plate side more than the outer peripheral-side engaging convex portions and the inner peripheral-side engaging convex portions, in a state of the stop release position of the movable-side engaging plate, only the circular ring-shaped front end portion of the circular ring-shaped protruding portion is inserted into the circular ring-shaped groove portion of the fixed-side engaging plate, the outer peripheral-side engaging convex portions and the inner peripheral-side engaging convex portions are separated from the outer peripheral-side engaging concave portions and the inner peripheral-side engaging concave portions, respectively, and the fixed-side engaging plate and the movable-side engaging plate are relatively rotatable, in a state of the stop position of the movable-side engaging plate, the outer peripheral-side engaging convex portions and the inner peripheral-side engaging convex portions are inserted into the outer peripheral-side engaging concave portions and the inner peripheral-side engaging concave portions, respectively, and the fixed-side engaging plate and the movable-side engaging plate are in an engaged state in which relative rotation is not possible.

2. The motor brake according to claim 1, characterized in that the solenoid is a self-holding type solenoid that comprises: a frame; ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ a plunger core supported by the frame so as to be movable in the axial direction; a magnetic circuit including a coil that generates an electromagnetic force for moving the plunger core to a retracted position and a projected position in the axial direction; and a permanent magnet that generates an attractive force for holding the plunger core moved to the retracted position and the projected position in the position, the movable-side engagement plate is installed to the plunger core, and in the retracted position of the plunger core, the movable-side engagement plate is in the stop release position, and in the projected position of the plunger core, the movable-side engagement plate is in the stop position. ​

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