Electromagnetic brake

Abstract

Reduce the volume of the electromagnetic brake's outer casing. [Solution] The present invention relates to an electromagnetic brake including a stator and a rotor. The stator includes an outer shell, two coils, a friction section, and a permanent magnet. The outer shell includes an outer ring section, an inner ring section, a bottom, and an annular groove. The outer ring section is positioned around the inner ring section, and the bottom is connected between one side of the outer ring section and one side of the inner ring section. The outer ring section, inner ring section, and bottom together form an annular groove, and the two coils are positioned within the annular groove. The friction section is positioned away from the bottom of the outer shell and includes an inner friction plate and an outer friction plate. The outer friction plate is positioned around the inner friction plate, and the permanent magnet is positioned orbitally between the inner and outer friction plates. The rotor is rotatably connected to the stator and includes an armature. The armature is positioned opposite the friction section, and the friction section and the permanent magnet are located between the armature and the outer shell.

Description

Technical Field

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[0001] The present invention relates to brakes, particularly electromagnetic brakes.

Background Art

[0002] Currently, electromagnetic brakes are widely used in robotic arms and various motors, and have become an essential key component in Industry 4.0. Conventional electromagnetic brakes are composed of a combination of a single coil and a permanent magnet, and are assembled with press parts and cutting parts. Along with the requirements for miniaturization of robotic arms and various motors, the space for installing components inside them is limited, and there is a demand for thinner and smaller outer diameters for electromagnetic brakes.

[0003] Under the condition that the volume of the electromagnetic brake is limited, the generated braking force is likely to decrease. Currently, in order to improve the braking force of the electromagnetic brake, the voltage is increased when the electromagnetic brake is activated, and when the operating position of the electromagnetic brake reaches a predetermined position, the voltage is decreased to the original supply voltage. When the electromagnetic brake has only a single coil, it is necessary to use an external power supply device to control the increase and decrease of the voltage. As a result, not only does it lead to an increase in the control device and cost, but also energy consumption occurs during the process of increasing and decreasing the voltage.

[0004] Therefore, it is currently urgently necessary to develop an electromagnetic brake that overcomes the above disadvantages.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is to provide an electromagnetic brake. The electromagnetic brake includes two coils arranged in a first annular groove of the outer shell, and the two coils can achieve the effect of reducing the overall power loss of the power supply depending on the driving method with different timings. Furthermore, the friction part of the electromagnetic brake of the present invention includes an inner friction plate and an outer friction plate, and a permanent magnet is arranged circumferentially between the inner friction plate and the outer friction plate, and the friction part and the permanent magnet are located between the armature and the outer shell. Due to the above structural features, the electromagnetic brake of the present invention can reduce the installation volume of the outer shell. [Means for solving the problem]

[0006] To achieve the above objective, one embodiment of the present invention is an electromagnetic brake comprising a stator and a rotor. The stator comprises an outer shell, two coils, a friction section, and a permanent magnet. The outer shell comprises an outer ring section, an inner ring section, a first bottom, and a first annular groove, the outer ring section being positioned around the inner ring section, the first bottom being connected between one side of the outer ring section and one side of the inner ring section, and the outer ring section, inner ring section, and first bottom together forming a first annular groove. The two coils are positioned within the first annular groove. The friction section is positioned on the side of the outer shell away from the first bottom and comprises an inner friction plate and an outer friction plate, the outer friction plate being positioned around the inner friction plate. The permanent magnet is positioned orbitally between the inner and outer friction plates. The rotor is rotatably connected to the stator and comprises an armature. The armature is positioned opposite the friction section, and the friction section and the permanent magnet are located between the armature and the outer shell. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing the structure of the electromagnetic brake of the present invention. [Figure 2] Figure 1 is a schematic diagram showing the structure of the stator and rotor of the electromagnetic brake. [Figure 3] Figure 1 is a schematic diagram showing the cross-sectional structure of the electromagnetic brake. [Figure 4]Figure 1 is a schematic diagram showing the disassembled structure of the electromagnetic brake. [Figure 5] This is a schematic diagram showing the circuit configuration of a brake control circuit for controlling an electromagnetic brake according to the present invention. [Figure 6] Figure 5 shows the switching timing diagram of the brake control circuit. [Figure 7A] Figure 1 is a side view of the electromagnetic brake when it is not energized. [Figure 7B] Figure 1 is a side view of the electromagnetic brake when energized. [Modes for carrying out the invention]

[0008] Several typical embodiments illustrating the features and advantages of the present invention will be described in detail in the following description. The present invention can have various variations in different embodiments, none of which will depart from the scope of the invention, and it should be understood that the description and drawings are used essentially for illustrative purposes and are not intended to limit the invention.

[0009] Refer to Figures 1 to 4. Figure 1 is a schematic diagram showing the structure of the electromagnetic brake of the present invention, Figure 2 is a schematic diagram showing the structure of the stator and rotor of the electromagnetic brake shown in Figure 1, Figure 3 is a schematic diagram showing the cross-sectional structure of the electromagnetic brake shown in Figure 1, and Figure 4 is a schematic diagram showing the exploded structure of the electromagnetic brake shown in Figure 1. As shown, the electromagnetic brake 1 of the present invention is applicable to robot arms and motors and includes a rotor 2 and a stator 3. The rotor 2 includes a hub 21, three leaf springs 22, an armature 23, and three first fixing members 24. The hub 21 includes a rotating shaft 211, an annular portion 212, and three first through holes 213. The rotating shaft 211 is a columnar structure with a hollow portion, the annular portion 212 is arranged on the outer circumferential surface of the rotating shaft 211, and the three first through holes 213 are spaced apart around the rotating shaft 211 and drilled in the annular portion 212. The first fixing member 24 described above may be a screw or a rivet, but is not limited to these.

[0010] The three leaf springs 22 are positioned on the side of the annular portion 212 of the hub 21 facing the stator 3 and are arranged around the pivot axis 211. Each leaf spring 22 includes at least one second through hole 221, each second through hole 221 aligning with a corresponding first through hole 213 of the hub 21. The armature 23 is positioned on the side of the annular portion 212 of the hub 21 facing the stator 3, and the three leaf springs 22 are located between the annular portion 212 of the hub 21 and the armature 23. The armature 23 includes a first placement hole 231 and three third through holes 232, the first placement hole 231 being located in the center of the armature 23 to position the pivot 211 of the hub 21, the three third through holes 232 being arranged around the first placement hole 231, each third through hole 232 being aligned with a corresponding first through hole 213 and a corresponding second through hole 221. Each first fixing member 24 fastens the hub 21, the leaf spring 22 and the armature 23 to each other by passing through the corresponding first through hole 213 of the hub 21, the corresponding second through hole 221 of the leaf spring 22 and the corresponding third through hole 232 of the armature 23.

[0011] The stator 3 is rotatably connected to the rotor 2 and includes an outer shell 31, a first coil 321, a second coil 322, an inner shell 33, control components 34, friction parts 35, a permanent magnet 36, a copper plate 37, and four second fixing members 38. The outer shell 31 includes an outer ring portion 311, an inner ring portion 312, a first bottom portion 313, and a first annular groove 314, the outer ring portion 311, the inner ring portion 312, the first bottom portion 313, and the first annular groove 314 being integrally formed structures. The outer ring portion 311 is positioned around the inner ring portion 312, which includes a fourth arrangement hole 312a and four sixth through holes 312b, the fourth arrangement hole 312a being located in the center of the inner ring portion 312, and the four sixth through holes 312b being positioned around the fourth arrangement hole 312a. The first bottom portion 313 is connected to the side of the outer ring portion 311 away from the rotor 2 and to the side of the inner ring portion 312 away from the rotor 2. The outer ring portion 311, the inner ring portion 312, and the first bottom portion 313 all form a first annular groove 314, and the opening direction of the first annular groove 314 is toward the hub 21 of the rotor 2.

[0012] The first coil 321 is positioned within the first annular groove 314 of the outer shell 31 and around the inner ring portion 312. The second coil 322 is positioned within the first annular groove 314 of the outer shell 31 and around the inner ring portion 312. The second coil 322 is located between the first coil 321 and the outer ring portion 311 of the outer shell 31, and the first coil 321 is located between the inner ring portion 312 of the outer shell 31 and the second coil 322. The resistance value of the second coil 322 is different from the resistance value of the first coil 321.

[0013] In this embodiment, the inner shell 33 is positioned within the first annular groove 314 of the outer shell 31 and includes a second bottom portion 331, an upper ring portion 332, a lower ring portion 333, and a second annular groove 334. The second bottom portion 331 is positioned around the inner ring portion 312 of the outer shell 31, the upper ring portion 332 is formed extending from the side of the second bottom portion 331 away from the first bottom portion 313 toward the outer ring portion 311, and the lower ring portion 333 is formed extending from the side of the second bottom portion 331 adjacent to the first bottom portion 313 toward the outer ring portion 311. The second bottom portion 331, the upper ring portion 332, and the lower ring portion 333 together form the second annular groove 334, and the opening direction of the second annular groove 334 is toward the outer ring portion 311 of the outer shell 31. In this embodiment, the first coil 321 and the second coil 322 are arranged within the second annular groove 334 of the inner shell 33, and the first coil 321 is located on the inner circumference side of the second annular groove 334 of the inner shell 33 compared to the second coil 322.

[0014] The control component 34 consists of a circuit board 341 and an electric wire 342. The circuit board 341 is located within the first annular groove 314 of the outer shell 31, between the lower ring portion 333 of the inner shell 33 and the first bottom portion 313 of the outer shell 31. One end of the electric wire 342 is connected to the circuit board 341, at least a portion of the electric wire 342 passes through the outer ring portion 311 of the outer shell 31 and is located outside the outer shell 31, and the other end of the electric wire 342 is connected to an external control device (not shown).

[0015] The friction section 35 is located on the side of the outer shell 31 away from the first bottom 313 and is situated between the armature 23 and the outer shell 31. As shown in Figure 3, the friction section 35 includes an inner friction plate 351 and an outer friction plate 352. The inner friction plate 351 includes a second placement hole 351a and four fourth through holes 351b, the second placement hole 351a being located in the center of the inner friction plate 351 and the four fourth through holes 351b being arranged around the second placement hole 351a. The outer friction plate 352 is arranged around the inner friction plate 351, forming a gap 353 between the outer friction plate 352 and the inner friction plate 351. The permanent magnet 36 is arranged around the gap 353 between the inner friction plate 351 and the outer friction plate 352 of the friction section 35, and the permanent magnet 36 is located between the armature 23 and the outer shell 31 (as shown in Figure 3).

[0016] The copper plate 37 is located between the inner friction plate 351 of the friction section 35 and the inner ring section 312 of the outer shell 31, and includes a third placement hole 371 and four fifth through holes 372. The third placement hole 371 is located in the center of the copper plate 37 to accommodate the rotation axis 211 of the hub 21 and is aligned with the second placement hole 351a of the inner friction plate 351 and the first placement hole 231 of the armature 23. The four fifth through holes 372 are located around the third placement hole 371, and each fifth through hole 372 is aligned with the corresponding fourth through hole 351b of the inner friction plate 351. Each second fixing member 38 penetrates the corresponding fourth through hole 351b in the inner friction plate 351, the corresponding fifth through hole 372 in the copper plate 37, and the corresponding sixth through hole 312b in the inner ring portion 312 of the outer shell 31, thereby fixing the inner friction plate 351, the copper plate 37, and the outer shell 31 to each other.

[0017] Furthermore, the electromagnetic brake 1 of the present invention further includes a brake control circuit 9 provided on a circuit board 341. The brake control circuit 9 comprises an RC delay circuit and a PWM circuit, and the objective of controlling the switching timing of two coils (i.e., a first coil 321 and a second coil 322) is achieved by controlling the RC delay circuit and the PWM circuit. Refer to Figures 5, 6, 7A, and 7B in conjunction with Figures 1 to 4. Figure 5 is a schematic diagram showing the circuit configuration of the brake control circuit for controlling the electromagnetic brake of the present invention, Figure 6 is a switching timing diagram of the brake control circuit shown in Figure 5, Figure 7A is a side view of the electromagnetic brake shown in Figure 1 when it is not energized, and Figure 7B is a side view of the electromagnetic brake shown in Figure 1 when it is energized. As shown in Figure 5, the brake control circuit 9 of the present invention receives a DC voltage Vo (e.g., 24V) supplied from a DC power supply 8. The brake control circuit 9 further includes a first input terminal 91, a second input terminal 92, a first output terminal 93, a second output terminal 94, a third output terminal 95, a resistor R, a control unit 96, a first transistor S1, a second transistor S2, a first diode D1, and a second diode D2. The brake control circuit 9 receives a DC voltage Vo via the first input terminal 91 and the second input terminal 92, and outputs output voltages via the first output terminal 93, the second output terminal 94, and the third output terminal 95. The voltage output from the second output terminal 94 is called the first output voltage, and the voltage output from the third output terminal 95 is called the second output voltage. The first end of resistor R is connected to the first input terminal 91. The control unit 96 consists of an RC delay circuit and a PWM circuit and is connected between the second end of resistor R and the second input terminal 92. The first transistor S1 is a PMOS transistor, its gate is connected to the control unit 96, its source is connected to the second input terminal 92, and its drain is connected to the third output terminal 95. The second transistor S2 is an NMOS transistor, its gate is connected to the control unit 96, its source is connected to the second input terminal 92, and its drain is connected to the second output terminal 94.The cathode of the first diode D1 is connected to the first output terminal 93, and the anode of the first diode D1 is connected to the second output terminal 94. The cathode of the second diode D2 is connected to the second output terminal 94, and the anode of the second diode D2 is connected to the third output terminal 95. The ends of the first coil 321 of the electromagnetic brake 1 are connected to the first output terminal 93 and the second output terminal 94, respectively, and the ends of the second coil 322 are connected to the second output terminal 94 and the third output terminal 95, respectively.

[0018] When the brake control circuit 9 is not receiving voltage, as shown in Figures 4 and 7A, the friction portion 35 of the stator 3 attracts the armature 23 of the rotor 2 by the internal permanent magnet 36, and the contact between the armature 23 of the rotor 2 and the friction portion 35 of the stator 3 generates a braking effect. When the brake control circuit 9 receives a DC voltage Vo supplied from the DC power supply 8 via the first input terminal 91 and the second input terminal 92, the control unit 96 controls the operation of the first transistor S1 and the second transistor S2. As can be seen from Figure 6, between time t0 and time t1 (i.e., over-excitation time), the control unit 96 controls the first transistor S1 to turn off and the second transistor S2 to turn on, thereby supplying an output voltage from the second output terminal 94 to supply current to the first coil 321 and operate it. As shown in Figures 4 and 7B, when the first coil 321 is energized, a magnetic field is generated in the opposite direction to the permanent magnet 36, canceling out the magnetic field of the permanent magnet 36 itself. As a result, the armature 23 of the rotor 2 is released from the attraction of the permanent magnet 36 in the friction part 35 of the stator 3, a gap is formed between the armature 23 and the friction part 35, and the brake release effect is obtained.

[0019] Subsequently, when the RC delay circuit in the control unit 96 delays the DC voltage Vo by several milliseconds and reaches between time t1 and time t2 (i.e., the steady excitation time), the control unit 96 controls to turn on the first transistor S1 and turn off the second transistor S2. Thereby, the third output terminal 95 also supplies an output voltage, and current flows through the first coil 321 and the second coil 322 to operate, maintaining the state shown in FIG. 7B. As can be seen from the above description, the braking release force provided by the first coil 321 is relatively large and is used to activate the braking release function of the electromagnetic brake 1. The braking release force provided by the first coil 321 and the second coil 322 together is relatively small and is used to maintain the braking release function of the electromagnetic brake 1. By the above control method, while maintaining the output current at at least 40% (since a low current for maintaining braking release is sufficient), the power consumption of the entire power supply can be reduced.

[0020] As described above, the electromagnetic brake of the present invention includes two coils arranged in the first annular groove of the outer shell. The two coils can achieve the effect of reducing the power loss of the entire power supply according to different timing driving methods. Furthermore, the friction part of the electromagnetic brake of the present invention includes an inner friction plate and an outer friction plate. The permanent magnet is circumferentially arranged between the inner friction plate and the outer friction plate. The friction part and the permanent magnet are located between the armature and the outer shell. Due to the above structural features, the electromagnetic brake of the present invention can achieve miniaturization of the outer shell.

Explanation of Signs

[0021] 1: Electromagnetic brake 2: Rotor 21: Hub 211: Rotating shaft 212: Annular part 213: First through hole 22: Leaf spring 221: Second through hole 23: Armature 231: First arrangement hole 232: Third through hole 24: First fixing member 3: Stator 31: Outer shell 311: Outer ring section 312: Inner ring section 312a: 4th arrangement hole 312b: 6th through hole 313: 1st bottom 314: First annular groove 321: First coil 322: Second coil 33: Inner shell 331:Second bottom 332: Upper ring section 333: Lower ring section 334: Second annular groove 34: Control components 341: Circuit board 342: Electric wire 35:Friction part 351:Inner friction plate 351a: 2nd placement hole 351b: 4th through hole 352:Outer friction plate 353: Gap 36: Permanent magnet 37: Copper plate 371: 3rd placement hole 372: Fifth through hole 38: Second fixing member 8:DC power supply Vo: DC voltage 9: Control circuits 91: First input terminal 92: Second input terminal 93: First output terminal 94: Second output terminal 95: Third output terminal R: Resistance 96: Control Unit S1: First transistor S2: Second transistor D1: First diode D2: Second diode

Claims

1. An electromagnetic brake including a stator and a rotor, The stator includes an outer shell, two coils, a friction section, and a permanent magnet. The outer shell includes an outer ring portion, an inner ring portion, a first bottom portion, and a first annular groove, wherein the outer ring portion is arranged around the inner ring portion, the first bottom portion is connected between one side of the outer ring portion and one side of the inner ring portion, and the outer ring portion, the inner ring portion, and the first bottom portion together form the first annular groove. The two coils are arranged in the first annular groove, The friction portion is located on the side of the outer shell away from the first bottom and includes an inner friction plate and an outer friction plate, the outer friction plate being located around the inner friction plate. The permanent magnet is arranged in a circular manner between the inner friction plate and the outer friction plate. The rotor is rotatably connected to the stator and includes an armature. The armature is positioned opposite the friction portion, and the friction portion and the permanent magnet are located between the armature and the outer shell. Electromagnetic brake.

2. The electromagnetic brake according to claim 1, wherein the two coils each have different resistance values ​​and include a first coil and a second coil, the second coil being located between the first coil and the outer ring portion of the outer shell, and the first coil being located between the inner ring portion of the outer shell and the second coil.

3. The electromagnetic brake according to claim 1, wherein the rotor further includes a hub, the hub includes a rotating shaft, an annular portion, and a plurality of first through holes, the annular portion being disposed on the outer circumferential surface of the rotating shaft, and the plurality of first through holes being drilled in the annular portion and arranged around the rotating shaft.

4. The electromagnetic brake according to claim 3, wherein the rotor further comprises a plurality of leaf springs, each of which is positioned between the annular portion of the hub and the armature and comprises a plurality of second through holes, each of which is aligned with a corresponding first through hole.

5. The electromagnetic brake according to claim 4, wherein the armature includes a first positioning hole and a plurality of third through holes, the first positioning hole being located at the center of the armature for positioning the rotation axis of the hub, and the plurality of third through holes being arranged around the first positioning hole, with each third through hole being aligned with the corresponding first through hole and the corresponding second through hole.

6. The electromagnetic brake according to claim 5, wherein the rotor further includes a plurality of first fixing members, each of which passes through a corresponding first through hole, a corresponding second through hole, and a corresponding third through hole to fix the hub, the plurality of leaf springs, and the armature to each other.

7. The stator further includes an inner shell, which is positioned within the first annular groove of the outer shell and includes a second bottom portion, an upper ring portion, a lower ring portion, and a second annular groove. The second bottom portion is positioned around the inner ring portion of the outer shell, the upper ring portion is formed extending from one side of the second bottom portion toward the outer ring portion of the outer shell, and the lower ring portion is formed extending from the other side of the second bottom portion toward the outer ring portion of the outer shell, and the second bottom portion, the upper ring portion, and the lower ring portion all form the second annular groove, and the opening direction of the second annular groove is toward the outer ring portion of the outer shell. The electromagnetic brake according to claim 1, wherein the two coils are arranged in the second annular groove.

8. The stator further includes control components, the control components consisting of a circuit board and wires. The electromagnetic brake according to claim 7, wherein the circuit board is disposed in the first annular groove of the outer shell and is located between the lower ring portion of the inner shell and the first bottom portion of the outer shell, the electric wire is connected to the circuit board, and at least a portion of the electric wire passes through the outer ring portion of the outer shell and is located outside the outer shell.

9. The electromagnetic brake further includes a brake control circuit provided on a circuit board, The electromagnetic brake according to claim 7, wherein the brake control circuit comprises an RC delay circuit and a PWM circuit, and the switching timing of the two coils is controlled by controlling the RC delay circuit and the PWM circuit.

10. The electromagnetic brake according to claim 1, wherein the inner friction plate of the friction portion includes a second arrangement hole and a plurality of fourth through holes, the second arrangement hole is located at the center of the inner friction plate, and the plurality of fourth through holes are arranged around the second arrangement hole.

11. The stator further includes a copper plate, the copper plate being located between the inner friction plate of the friction portion and the inner ring portion of the outer shell, and including a third arrangement hole and a plurality of fifth through holes. The electromagnetic brake according to claim 10, wherein the third arrangement hole is located in the center of the copper plate and is aligned with the second arrangement hole and the first arrangement hole of the armature, and the plurality of fifth through holes are arranged around the third arrangement hole, with each of the fifth through holes being aligned with the corresponding fourth through hole.

12. The inner ring portion of the outer shell includes a fourth arrangement hole and a plurality of sixth through holes, The electromagnetic brake according to claim 11, wherein the fourth arrangement hole is located in the center of the inner ring portion and is aligned with the second arrangement hole and the third arrangement hole, and the plurality of sixth through holes are arranged around the fourth arrangement hole, and each of the sixth through holes is aligned with the corresponding fifth through hole and the corresponding fourth through hole.

13. The electromagnetic brake according to claim 12, wherein the stator further includes a plurality of second fixing members, each of which passes through a corresponding fourth through hole, a corresponding fifth through hole, and a corresponding sixth through hole.

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