Electric machine and actuator

Abstract

The utility model discloses a compact structure's motor and the actuator including it, the motor includes stator and rotatablely arranged in the rotor of stator, the side end of stator is equipped with end cover, the first friction piece of fixed setting is equipped with in the end cover, the rotor includes the rotating shaft, the second friction piece of fixed setting is equipped with on the rotating shaft, the motor has at least first state and second state, in first state, the second friction piece and first friction piece are separated in axial direction, in second state, the first friction piece and second friction piece abut in axial direction and form friction brake, so that the rotor can stop rotating within the prescribed time when the motor is powered off, and further make the load driven by motor rotor can stop quickly.

Description

Technical Field

[0001] This utility model relates to the field of electric motors, and more specifically to a compact electric motor capable of rapid braking and an actuator including the motor. Background Technology

[0002] As is well known, because the rotating parts of an electric motor have inertia, under normal circumstances, after the power is cut off, the rotor will continue to rotate for a certain period of time before it can stop completely due to inertia. In order to brake the motor quickly, an additional braking structure is usually added to the outside of the motor housing. This results in the motor occupying a large space when in use. Even if the motor is small, the braking structure will still occupy a relatively large area.

[0003] With the rapid development of industrial automation, new energy vehicles, smart homes, and other fields, equipment integration and miniaturization have become inevitable trends. Additional braking structures increase the weight and size of the entire vehicle or electronic equipment, which contradicts the design principles of lightweight and high efficiency. Utility Model Content

[0004] In view of this, the present invention aims to provide an electric motor and an actuator having the electric motor, which can provide a fast braking function while having a simple and compact structure and low cost.

[0005] On one hand, this utility model provides an electric motor, which includes a stator and a rotor rotatably disposed in the stator. An end cover is disposed on the side end of the stator, and a first friction element is fixedly disposed in the end cover. The rotor includes a rotating shaft, and a second friction element is fixedly disposed on the rotating shaft. The electric motor has at least a first state and a second state. In the first state, the second friction element and the first friction element are axially separated. In the second state, the first friction element and the second friction element abut against each other in the axial direction to form friction.

[0006] The motor may exhibit one or more of the following features, either individually or in combination.

[0007] In some embodiments, the first friction element and the second friction element are coaxially mounted along the axis of the rotating shaft, the outer diameter of the second friction element is not greater than the outer diameter of the first friction element, and the first friction element is clearance-fitted with the rotating shaft.

[0008] In some embodiments, on a projection plane perpendicular to the axis, the outer contour of the second friction element is located inside the closed pattern formed by the outer contour of the first friction element.

[0009] In some embodiments, when the motor rotates in a first direction, the first and second friction elements separate axially; when the motor rotates in a second direction opposite to the first direction, the first and second friction elements contact each other, and the driving force between the rotor and the stator is greater than the frictional force between the first and second friction elements.

[0010] In some embodiments, the motor is in a first state when it rotates in a first direction; and in a second state when it rotates in a second direction or is in a power-off shutdown state.

[0011] In some embodiments, the end cap is provided with a bearing hole and an assembly hole in sequence in the axial direction, the diameter of the bearing hole is smaller than the diameter of the assembly hole; a bearing is installed in the bearing hole, and the first friction element is fixed in the assembly hole.

[0012] In some embodiments, the end cap is further provided with a clearance hole, the diameter of the mounting hole is smaller than the diameter of the clearance hole, and the second friction member is rotatably accommodated in the clearance hole.

[0013] In some embodiments, the first friction element is a disc-shaped component made of a metallic material, and the second friction element is a disc-shaped component made of an organic material.

[0014] In some embodiments, the first friction element is a powder metallurgy component, and the second friction element is a bakelite friction element or a brake pad composite material friction element.

[0015] On the other hand, the present invention provides an actuator, including a reduction mechanism and a motor as described in any of the above.

[0016] Compared with the prior art, the motor and actuator provided by this utility model are equipped with a first friction element and a second friction element on the end cover and rotor of the motor, respectively. When the motor is powered off, friction braking is formed by the contact of the two friction elements to overcome rotational inertia, so that the motor rotor can stop rotating within a specified time. The braking mechanism is set inside the motor, saving installation space, simplifying system integration, and is suitable for compact equipment design. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of one embodiment of the motor of the actuator of this utility model.

[0018] Figure 2 for Figure 1 The top view of the motor shown.

[0019] Figure 3 for Figure 1 The exploded view of the motor shown.

[0020] Figure 4 for Figure 1An exploded view of the motor from another angle.

[0021] Figure 5 for Figure 2 The motor shown is a cross-sectional view along line VV.

[0022] Figure 6 This is a cross-sectional view of the motor in another state.

[0023] Figure 7 for Figure 5 Enlarged view of circle VII in the center.

[0024] Figure 8 for Figure 6 A magnified view of center circle VIII.

[0025] Figure 9 This is a schematic diagram of an embodiment of the actuator of this utility model.

[0026] Explanation of icon numbers:

[0027] 100. Electric motor;

[0028] 20. Stator; 22. Stator housing; 221. Second shaft hole; 24. Permanent magnet;

[0029] 30. Rotor; 32. Shaft; 33. Iron core; 34. Coil; 36. Commutator; 38. Second friction element; 381. Second friction surface;

[0030] 40. End cap; 401. First shaft hole; 403. Assembly hole; 405. Clearance hole; 42. Brush; 44. First bearing; 46. Second bearing; 48. First friction element; 481. First friction surface;

[0031] 50. Circuit board; 52. Sensor; 54. Magnetic ring.

[0032] 200. Transmission mechanism Detailed Implementation

[0033] To facilitate understanding of this utility model, a more comprehensive description will be provided below with reference to the accompanying drawings. One or more embodiments of this utility model are exemplarily shown in the drawings to enable a more accurate and thorough understanding of the disclosed technical solutions. However, it should be understood that this utility model can be implemented in many different forms and is not limited to the embodiments described below.

[0034] This utility model provides a motor and an actuator including the motor, which can be used in vehicles to drive loads to move or rotate, such as in electric vehicles to drive the cover of its charging port to open and close, or to drive the windows to rise and fall, or the seats to adjust in multiple directions.

[0035] Figure 1-4 The figure shown is a specific embodiment of the actuator of this utility model. The actuator includes a motor 100 and a transmission mechanism 200 that cooperates with it (see figure 200). Figure 9 The motor 100 includes a stator 20 and a rotor 30 rotatably disposed at the center of the stator 20. A transmission mechanism 200 connects the rotor 30 and the load (such as a charging port cover, window, or seat in a vehicle). This mechanism can be a worm gear, rack and pinion, etc., to meet the transmission requirements for power reduction and torque change, enabling the load to rotate or move at an appropriate speed. The specific structure of the transmission mechanism can refer to the relevant structures of existing actuators, and will not be elaborated here.

[0036] The motor 100 is preferably a permanent magnet direct current (PMDC) motor, which has advantages such as small size, high efficiency, and simple structure. Specifically, for example... Figure 3-4 As shown, the stator 20 of the motor 100 includes a cylindrical stator shell 22 and a permanent magnet 24 attached to the inner wall of the stator shell 22; the rotor 30 of the motor 100 includes a shaft 32, an iron core 33 sleeved on the shaft 32, and a coil 34 wound on the iron core 33. When the coil 34 of the rotor 30 is energized, it generates a periodically changing magnetic field, which interacts with the magnetic field of the permanent magnet 24 of the stator 20, driving the rotor 30 to rotate continuously. The transmission mechanism is connected to the shaft 32 of the rotor 30, driving the load to rotate or move at an appropriate speed.

[0037] The motor 100 is preferably a brushed motor. In this embodiment, one end of the stator housing 22 is open to facilitate the assembly of the rotor 30, etc. An end cover 40 covers the open end of the stator housing 22 and extends partially into the stator housing 22. A brush 42 is arranged on the side of the end cover 40 facing the rotor 30, and a commutator 36 is arranged on the end of the shaft 32 near the end cover 40. The commutator 36 has multiple commutator segments, each of which is electrically connected to a coil 34. During the rotation of the rotor 30, the brush 42 sequentially contacts or separates from each commutator segment of the commutator 36, causing the corresponding coil 34 to be energized or de-energized, thereby generating a periodically changing magnetic field.

[0038] In this embodiment, a circuit board 50 is provided on the outer side of the end cover 40 (i.e., the side facing away from the rotor 30) for connecting an external power source to supply power to the brush 42. The circuit board 50 can be fixed to the end cover 40 by screws or the like, and the terminals of the brush 42 pass through the end cover 40 and are electrically connected to the circuit board 50. Preferably, a Hall sensor 52 is provided on the circuit board 50, and one end of the rotating shaft 32 (e.g., ...) is connected to the brush 42. Figure 5 The top of the rotor (as shown) extends outward through the end cap 40 and the circuit board 50. A magnetic ring 54 is fixedly sleeved on the rotating shaft 32 and corresponds to the Hall sensor 52. By sensing the change in the magnetic field of the magnetic ring 54 through the Hall sensor 52, the position of the rotor 30 can be determined, thereby controlling the operation of the motor 100.

[0039] Please also refer to Figure 5 , Figure 7 The end cover 40 has a first shaft hole 401 in its center, and a first bearing 44 is disposed in the first shaft hole 401. The stator housing 22 has a second shaft hole 221 in its center on the side opposite to the end cover 40, and a second bearing 46 is disposed in the second shaft hole 221. Both ends of the rotating shaft 32 pass through the first bearing 44 and the second bearing 46 respectively and extend beyond the end cover 40 and the stator housing 22, facilitating connection with other devices, such as transmission mechanisms. In this embodiment, the end of the rotating shaft 32 that extends out of the second bearing 46 is connected to a worm gear, which drives the load in conjunction with the worm wheel. The first bearing 44 and the second bearing 46 can be sliding bearings, and are preferably lubricated with lubricating oil between them and the rotating shaft 32 to reduce frictional resistance during relative rotation, making the rotation of the rotor 30 more stable and smooth.

[0040] A first friction element 48 is fixedly disposed on the end cap 40, and a second friction element 38 is fixedly disposed on the rotating shaft 32. Both the first friction element 48 and the second friction element 38 are disc-shaped, and their opposing surfaces respectively form a first friction surface 481 and a second friction surface 381. During operation, the motor 100 has at least a first state and a second state. In the first state, the second friction surface 381 and the first friction surface 481 are separated axially; in the second state, the first friction surface 481 and the second friction surface 381 abut axially to form friction braking, so that the rotor 30 of the motor 100 can stop within a specified time after the power is cut off.

[0041] The first friction element 48 is preferably made of a metallic material, such as copper, iron, or powder metallurgy. Its first friction surface 481 can be treated after forming to have a certain roughness, which can provide sufficient friction. It should be understood that the first friction element 48 is not limited to the above-mentioned materials, as long as it can cooperate with the second friction element 38 to achieve friction braking.

[0042] The second friction element 38 is preferably made of organic materials, such as bakelite, brake pad composite materials, rubber, etc., and its second friction surface 381 can be treated after molding to have a certain roughness to provide sufficient friction. It should be understood that the second friction element 38 is not limited to the above-mentioned materials, as long as it can cooperate with the first friction element 48 to achieve friction braking.

[0043] Specifically, the end cap 40 also has a mounting hole 403, which is sequentially arranged in the axial direction and interconnected with the first shaft hole 401. Preferably, the diameter of the mounting hole 403 is larger than the diameter of the first shaft hole 401, so that the interface between the two forms a stepped surface. The first friction element 48 is disposed in the mounting hole 403, preferably fixed in the mounting hole 403 by means of tight fit, bonding, welding, etc. When the first friction element 48 is installed in the mounting hole 403, it can be positioned in the axial direction by means of the stepped surface.

[0044] Preferably, a small gap is formed between the first friction element 48 and the rotating shaft 32, which ensures that the first friction element 48 does not affect the rotation of the rotating shaft 32. Furthermore, through the tight fit between the first friction element 48 and the mounting hole 403 of the end cover 40, the lubricating oil in the first bearing 44 will essentially not reach the locations of the first friction element 48 and the second friction element 38, thus affecting the braking effect when the first friction surface 481 and the second friction surface 381 come into contact. Simultaneously, the sealing effect of the first friction element 48 prevents the lubricating oil from being thrown out of the first shaft hole 401, resulting in better lubrication between the first bearing 44 and the rotating shaft 32.

[0045] The second friction element 38 is sleeved on the rotating shaft 32, and the two are fixed in the circumferential direction by a tight fit to rotate synchronously. Preferably, the outer diameter of the second friction element 38 is not greater than the outer diameter of the first friction element 48, so that the second friction element 38 and the end cover 40 have a radial clearance fit and will not cause interference or friction. The end cover 40 also has a clearance hole 405 to accommodate the second friction element 38, making the structure of the motor more compact. The clearance hole 405, the mounting hole 403, and the first shaft hole 401 are arranged sequentially in the axial direction and communicate with each other. Preferably, the diameter of the clearance hole 405 is larger than the diameter of the mounting hole 403. Of course, the first friction element 48 and the second friction element 38 are not limited to a disc shape and can be other shapes, as long as the outer contour of the second friction element 38 is located inside the closed shape formed by the outer contour of the first friction element 48 on the projection plane perpendicular to the axis.

[0046] For example, 5. Figure 7 As shown, when the actuator is not turned on, the motor is not powered on, the motor rotor 30 is in the initial position, and the second friction surface 381 of the second friction member 38 on its shaft 32 abuts against the first friction surface 481 of the first friction member 48 in the end cover 40.

[0047] When the actuator starts rotating in a predetermined first direction (e.g., clockwise), the motor is energized, current flows through the rotor windings, and an electromagnetic force is generated between the stator and rotor, driving the rotor 30 to rotate. The axial force generated by the worm gear reduction mechanism in the actuator during worm gear transmission pulls the rotor 30 to float towards the side away from the end cover 40, causing the second friction element 38 to separate from the first friction element 48. Figure 6 , Figure 8 As shown, the motor 100 is in the first state at this time. The rotation of the motor 100 drives the load to move or rotate accordingly, such as opening the cover of the charging port or lowering the car window.

[0048] When the actuator is de-energized, it stops driving the load. At this time, the motor 100 is in the second state, the electromagnetic force disappears, the axial force between the worm gear and the worm disappears, the shaft 32 floats axially toward the side where the end cover 40 is located, and the rotor 30 returns to the initial position, causing the second friction element 38 to come into contact with the first friction element 48 and generate friction, thereby overcoming the rotational inertia of the rotor 30 and enabling the rotor 30 to stop rotating within a specified time, achieving rapid friction braking.

[0049] When the actuator is activated again and rotates in a second direction opposite to the first direction (e.g., counterclockwise), causing the load to move or rotate, such as closing the charging port cover or raising the car window, the motor 100 is energized, current flows through the rotor windings, and an electromagnetic force is generated between the stator and rotor, driving the rotor to rotate counterclockwise. The axial force between the worm gears pushes the rotor 30 to float axially toward the side where the end cover 40 is located. During this process, the second friction element 38 and the first friction element 48 remain in contact due to the axial force of the worm gears. However, because the driving force on the rotor 30 generated by the magnetic field of the stator and rotor 20 is much greater than the frictional force between the first friction element 48 and the second friction element 38, the rotor 30 can overcome friction and continue to rotate.

[0050] When the load returns to its initial position, the actuator is de-energized again. At this time, the second friction element 38 and the first friction element 48 remain in contact. Moreover, since the rotor 30 is no longer driven, the friction between the second friction element 38 and the first friction element 48 can overcome the rotational inertia of the rotor 30, causing the rotor 30 to stop rotating within a specified time, thus achieving braking.

[0051] This invention achieves friction braking by configuring a first friction element 48 on the end cover 40 of the motor 100 and a second friction element 38 on the rotor 30. The cooperation of the first and second friction elements 48 enables the rotor 30 to stop rapidly upon power failure, thus stopping the load driven by the rotor 30 from moving or rotating within a specified time, avoiding excessive movement caused by the rotor 30's inertia. Furthermore, the cooperation between the first friction element 48 and the end cover 40 effectively seals off the lubricating oil, preventing it from flowing to the first and second friction surfaces 481 and affecting the friction braking effect. It also prevents lubricating oil from flowing to the commutator and affecting the motor's operation.

[0052] It should be understood that the actuator can be applied to drive any other load, not limited to opening and closing the cover of the charging port, driving the windows or seats, etc., nor limited to vehicles. It can also be applied to drive roller blinds and achieve rapid braking, etc. The brake device of the motor of this utility model is set inside the motor, which has a simple structure, is easy to assemble, saves installation space, simplifies system integration, and is suitable for compact equipment design.

[0053] It should be noted that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, such as combining different features in various embodiments, and these should all fall within the protection scope of the present invention.

Claims

1. An electric machine comprising a stator and a rotor rotatably disposed in said stator, characterized by, The stator is provided with an end cover on its side, and a first friction element is fixedly disposed in the end cover. The rotor includes a rotating shaft, and a second friction element is fixedly disposed on the rotating shaft. The motor has at least a first state and a second state. In the first state, the second friction element and the first friction element are separated in the axial direction. In the second state, the first friction element and the second friction element abut in the axial direction to form friction.

2. The electric machine of claim 1, wherein, The first friction element and the second friction element are coaxially mounted along the axis of the rotating shaft. The outer diameter of the second friction element is not greater than the outer diameter of the first friction element, and the first friction element is clearance-fitted with the rotating shaft.

3. The electric machine of claim 1, wherein, On a projection plane perpendicular to the axis, the outer contour of the second friction element is located inside the closed shape formed by the outer contour of the first friction element.

4. The electric machine of claim 1, wherein, When the motor rotates in the first direction, the first and second friction components separate axially; when the motor rotates in the second direction opposite to the first direction, the first and second friction components come into contact, and the driving force between the rotor and the stator is greater than the friction force between the first and second friction components.

5. The electric machine of claim 4, wherein, The motor is in the first state when it rotates in the first direction; the motor is in the second state when it rotates in the second direction or when it is powered off and stopped.

6. The electric machine of claim 1, wherein, The end cap is provided with bearing holes and assembly holes in sequence along the axial direction. The diameter of the bearing holes is smaller than the diameter of the assembly holes. A bearing is installed in the bearing holes, and the first friction element is fixed in the assembly holes.

7. The electric machine of claim 6, wherein, The end cap is also provided with a clearance hole, the diameter of the assembly hole is smaller than the diameter of the clearance hole, and the second friction element is rotatably accommodated in the clearance hole.

8. The electric machine of any one of claims 1-7, wherein, The first friction element is a disc-shaped component made of a metallic material, and the second friction element is a disc-shaped component made of an organic material.

9. The electric machine of claim 6, wherein, The first friction component is a powder metallurgy component, and the second friction component is a bakelite friction component or a brake pad composite material friction component.

10. An actuator, characterized by It includes a speed reduction mechanism and the motor as described in any one of claims 1-9.

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