CN216851561U - Brushless motor for vehicle braking system and vehicle braking system - Google Patents

Abstract

The utility model discloses a brushless motor for a vehicle braking system and the vehicle braking system, wherein a stator assembly and a rotor assembly of the brushless motor for the vehicle braking system are both arranged in a shell, the rotor assembly comprises a rotating shaft and a rotor arranged on the rotating shaft, and a first bearing is arranged between the rotating shaft and the shell; the second bearing is arranged between the rotating shaft and the shell, and the first bearing and the second bearing are arranged on two axial sides of the stator assembly at intervals. This brushless motor for vehicle braking system, the support performance to the pivot is good, can prevent effectively that the rotor subassembly from taking place to heel at the pivoted process, has effectively guaranteed the axiality of stator module and rotor subassembly, has effectively guaranteed that the magnetic field clearance that forms between stator module and the rotor subassembly is even, has improved brushless motor for vehicle braking system's working property.

Description

Brushless motor for vehicle braking system and vehicle braking system

Technical Field

The utility model relates to a vehicle braking technical field especially relates to a brushless motor and vehicle braking system for vehicle braking system.

Background

With the continuous development of scientific technology, the application technology of the direct current brushless motor control system is more perfect and mature, and the direct current brushless motor control system has a series of advantages of simple structure, reliable operation, small operation sound, long service life, convenient maintenance and the like of an alternating current motor, and also has a plurality of advantages of high operation efficiency, good speed regulation performance and the like of the direct current motor. In a brake boosting system of an automobile, a brushless motor is required, and electric energy is converted into hydraulic pressure through high-speed operation of the brushless motor.

The brushless motor for the vehicle braking system disclosed in the prior art, including motor housing, stator module and rotor subassembly, motor housing's internally mounted has stator module, stator module's inside coaxial rotation is provided with the rotor subassembly, the rotor subassembly is including the rotor core that is the tube-shape and the even magnet steel that sets up in the rotor core outside, the one end of rotor core is inserted in motor housing's one end and is linked to each other with motor housing through the bearing, the inside coaxial arrangement of rotor core has the lead screw that links to each other with rotor core one end is fixed, screw nut on the lead screw is connected with helping hand jar piston transmission, the motor drives rotor core and rotates, and then drive the lead screw and rotate, screw nut drives helping hand jar piston motion, helping hand jar piston promotes the hydraulic oil of helping hand jar, with hydraulic oil pressure feed to four wheel cylinder calliper, thereby realize brake function.

However, in the existing brushless motor for the vehicle braking system, a bearing is usually only arranged at one end of the rotor, and a single bearing has poor supporting performance for the rotor assembly, so that a rotating shaft of the rotor assembly has a phenomenon of tilting in a rotating process, the coaxiality of the stator assembly and the rotor assembly is difficult to ensure, and a magnetic field gap formed between the stator assembly and the rotor assembly is uneven, so that the brushless motor for the vehicle braking system has poor working performance.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a brushless motor and vehicle braking system for vehicle braking system to solve the poor pivot that leads to of vehicle braking system for brushless motor's support performance among the prior art and take place the problem of heeling at the pivoted in-process.

To achieve the purpose, the utility model adopts the following technical proposal:

a brushless motor for a vehicle braking system, comprising a housing, a rotor assembly and a stator assembly, wherein the stator assembly and the rotor assembly are both disposed in the housing, the rotor assembly comprises a rotating shaft and a rotor disposed in the rotating shaft, and further comprising:

the first bearing is arranged between the rotating shaft and the shell;

and the second bearing is arranged between the rotating shaft and the shell, and the first bearing and the second bearing are arranged on two axial sides of the stator assembly at intervals.

Specifically, the bearing further comprises a first limiting structure and a second limiting structure which are respectively located on two axial sides of the first bearing.

Specifically, first limit structure including form in epaxial first spacing face of commentaries on classics, second limit structure including set up in spacing face of second in the casing, the axial both ends of first bearing respectively with first spacing face with spacing face butt of second.

Specifically, the first limiting structure comprises a first limiting part connected with the shell, the second limiting structure comprises a second limiting surface arranged in the shell, and two axial ends of the first bearing are respectively abutted to the first limiting part and the second limiting surface.

Specifically, the first limiting part is a clamp spring clamped to the housing; or the first limiting piece is a nut screwed with the shell.

Specifically, still include the elastic component, the elastic component butt in the axial outer end of second bearing and casing, the axial outer end is for keeping away from the one end of rotor.

Specifically, still include sealed lid, the casing is equipped with the draw-in groove, sealed lid joint in the draw-in groove.

Specifically, the sealing device further comprises a first sealing ring, and the first sealing ring is used for sealing the sealing cover and the shell along the axial direction of the rotating shaft.

Specifically, still include plug assembly, plug assembly includes the wiring board and is suitable for with the adapter of wiring board grafting, the wiring board be used for with the stator module electricity is connected, the adapter is used for electrically connecting with the controller.

The utility model provides a vehicle braking system, includes lead screw, screw nut, piston and brake master cylinder, the lead screw spiro union in screw nut, screw nut transmission connect in the piston, screw nut drives the piston with brake master cylinder sliding connection still includes foretell vehicle braking system and uses brushless motor, lead screw fixed connection in the pivot.

The utility model has the advantages that:

the utility model provides a brushless motor for vehicle braking system and vehicle braking system, the brushless motor for vehicle braking system includes a shell, a rotor component and a stator component, the stator component and the rotor component are all arranged in the shell, the rotor component includes a rotating shaft and a rotor arranged on the rotating shaft, wherein, the brushless motor for vehicle braking system also includes a first bearing and a second bearing, through arranging the first bearing between the rotating shaft and the shell, arranging the second bearing between the rotating shaft and the shell, and the first bearing and the second bearing are arranged on the axial both sides of the stator component at intervals, thereby, the first bearing and the second bearing support the rotor component simultaneously, compared with the prior art that only one bearing supports the rotating shaft, the brushless motor can effectively prevent the rotor component from tilting in the rotating process, thereby effectively ensuring the coaxiality of the stator component and the rotor component, the magnetic field gap formed between the stator assembly and the rotor assembly is effectively ensured to be uniform, and the working performance of the brushless motor for the vehicle braking system is improved.

Drawings

Fig. 1 is a schematic view of a part of a structure of a brushless motor for a vehicle braking system according to an embodiment of the present invention (a first limiting member is a nut);

fig. 2 is a cross-sectional view of a brushless motor for a vehicle brake system according to an embodiment of the present invention (a first stopper is a nut);

fig. 3 is a schematic structural diagram of a rotor assembly of a brushless motor for a vehicle braking system according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a part of a structure of a brushless motor for a vehicle braking system according to an embodiment of the present invention (the first limiting member is a nut);

fig. 5 is a schematic view of a part of a structure of a brushless motor for a vehicle braking system according to an embodiment of the present invention (the first limiting member is a snap spring).

In the figure:

1. a housing; 11. a housing main body; 111. a card slot; 12. a shell cover;

2. a rotor assembly; 21. a rotating shaft; 22. a rotor;

3. a stator assembly;

4. a first bearing;

5. a second bearing;

61. a first limiting surface; 62. a clamp spring; 63. a nut;

7. a second limiting surface;

8. an elastic member;

9. a sealing cover; 91. flanging;

10. a first seal ring;

20. a plug assembly; 201. a wiring board; 2011. an electric plug; 202. an adapter; 2021. a slot; 2022. a PIN needle; 2023. and a second seal ring.

Detailed Description

In order to make the technical problem solved by the present invention, the technical solutions adopted by the present invention and the technical effects achieved by the present invention clearer, the following will be described in further detail with reference to the accompanying drawings, and obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by the skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, detachably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The existing brushless motor for the vehicle braking system is usually only provided with a bearing at one end of a rotor, and the supporting performance of a single bearing on a rotor assembly is poor, so that the phenomenon of side inclination of a rotating shaft of the rotor assembly in the rotating process is caused, the coaxiality of the stator assembly and the rotor assembly is difficult to ensure, the magnetic field gap formed between the stator assembly and the rotor assembly is uneven, and the working performance of the brushless motor for the vehicle braking system is poor.

The utility model provides a brushless motor for vehicle braking system, as shown in fig. 1, this brushless motor for vehicle braking system includes casing 1, rotor subassembly 2 and stator subassembly 3, stator subassembly 3 and rotor subassembly 2 all set up in casing 1, rotor subassembly 2 includes pivot 21 and sets up in the rotor 22 of pivot 21, this brushless motor for vehicle braking system still includes first bearing 4 and second bearing 5, first bearing 4 is used for supporting pivot 21, the inner circle of first bearing 4 is fixed to be set up in pivot 21, the outer lane supports in casing 1; the second bearing 5 is also used for supporting the rotating shaft 21, the inner ring of the second bearing 5 is fixedly arranged on the rotating shaft 21, the outer ring is supported on the shell 1, and the first bearing 4 and the second bearing 5 are axially arranged at intervals on two axial sides of the stator assembly 3.

This brushless motor for vehicle braking system, as shown in fig. 1, the inner circle through with first bearing 4 and second bearing 5 is all fixed to be set up in pivot 21, support the outer lane of first bearing 4 and second bearing 5 in casing 1 respectively, and first bearing 4 and second bearing 5 interval set up in stator module 3's axial both sides, thereby, rotor module 2 is supported simultaneously to first bearing 4 and second bearing 5, only support pivot 21 through a bearing among the prior art, can prevent effectively that rotor module 2 from taking place to heeling at the pivoted process, thereby stator module 3 and rotor module 2's axiality has effectively been guaranteed, it is even effectively to have guaranteed that the magnetic field gap that forms between stator module 3 and the rotor module 2, vehicle braking system uses brushless motor's working property has been improved.

Further, the outer ring of the first bearing 4 is in interference fit with the inner wall of the housing body 11 of the housing 1, the inner ring of the first bearing 4 is in interference fit with the rotating shaft 21, the outer ring of the second bearing 5 is in interference fit with the inner wall of the housing body 11 of the housing 1, and the inner ring of the second bearing 5 is in interference fit with the rotating shaft 21. The stator assembly 3 comprises a stator iron core group, a stator winding wound inside the stator iron core group and a terminal assembly communicated with the stator winding, wherein the terminal assembly comprises a plurality of connecting sheets, and the terminal plate 201 of the plug assembly 20 is electrically connected with one of the connecting sheets.

Wherein one of the first bearing 4 and the second bearing 5 can simultaneously bear the axial load and the radial load given by the rotating shaft 21, and the other of the first bearing 4 and the second bearing 5 can bear at least the radial load given by the rotating shaft 21. By the arrangement, the radial load given by the rotating shaft 21 can be borne, the axial load given by the rotating shaft 21 can be borne, and the working performance of the brushless motor for the vehicle braking system is further improved.

As shown in fig. 2, the brushless motor for a vehicle brake system further includes a first limit structure and a second limit structure respectively located at two axial sides of the first bearing 4. By arranging the first limit structure and the second limit structure on two axial sides of the first bearing 4, the first limit structure and the second limit structure jointly limit the arrangement position of the first bearing 4 on the rotating shaft 21, so as to prevent the position of the first bearing 4 along the axial direction of the rotating shaft 21 from changing.

Specifically, the first limit structure and the second limit structure are arranged so that the first bearing 4 is used for bearing the axial load and the radial load given by the rotating shaft 21, and the second bearing 5 is used for bearing the radial load given by the rotating shaft 21. Thereby first bearing 4 and second bearing 5 can support pivot 21, prevent effectively that rotor subassembly 2 from taking place to heels in the pivoted process to effectively guaranteed stator module 3 and rotor subassembly 2's axiality, effectively guaranteed that the magnetic field clearance that forms between stator module 3 and the rotor subassembly 2 is even, improved vehicle brushless motor's for braking system working property.

Further, in the present embodiment, the first bearing 4 is a four-point contact ball bearing, and the second bearing 5 is a deep groove ball bearing.

Specifically, as shown in fig. 2 and fig. 3, the first limiting structure includes a first limiting surface 61 formed on the rotating shaft 21, the second limiting structure includes a second limiting surface 7 disposed on the housing 1, and two axial ends of the first bearing 4 are respectively abutted to the first limiting surface 61 and the second limiting surface 7. Specifically, the first limit surface 61 abuts against one end of the inner ring of the first bearing 4 close to the rotor 22; the second stopper surface 7 abuts against one end of the outer ring of the first bearing 4 away from the rotor 22.

As an alternative embodiment, the first limiting structure may further include a first limiting member, the first limiting member abuts against one end of the outer ring of the first bearing 4 close to the rotor 22, and the second limiting structure includes a second limiting surface 7 disposed on the housing 1, and the second limiting surface 7 abuts against one end of the outer ring of the first bearing 4 far away from the rotor 22. The arrangement position of the first bearing 4 is completely limited along the axial direction of the rotating shaft 21, and meanwhile, the first limiting structure and the second limiting structure can ensure that the first bearing 4 effectively bears the axial force given by the rotating shaft 21.

Wherein, the first limiting part is a clamp spring 62 clamped in the shell 1; or the first limiting member is a nut 63 screwed with the shell 1.

In the present embodiment, as shown in fig. 2 and 4, the first stopper is a nut 63 screwed with the housing 1. Specifically, the nut 63 is provided with a center hole, the rotating shaft 21 penetrates through the center hole of the nut 63 and is in clearance fit with the center hole, the nut 63 is provided with an external thread, the inner wall of the shell body 11 of the shell 1 is provided with an internal thread, and the internal thread is in threaded fit with the external thread so that the nut 63 abuts against the outer ring of the first bearing 4, the position of the outer ring of the first bearing 4 is effectively limited through the nut 63, and the first bearing 4 can effectively bear the axial load given by the rotating shaft 21.

Furthermore, the external thread of the nut 63 and the internal thread of the shell body 11 are coated with adhesive glue; alternatively, the nut 63 is riveted to the case body 11 with a rivet, thereby further enhancing the connection reliability of the nut 63 and the case body 11.

As an alternative, as shown in fig. 5, the first limiting member is a snap spring 62 snapped in the housing 1, and the snap spring 62 is snapped in the housing 1. Specifically, the inner wall of the housing body 11 of the housing 1 is provided with a first groove, the clamp spring 62 is clamped in the first groove along the radial portion, and the clamp spring 62 is abutted against the outer ring of the first bearing 4 along the radial portion, so that the position of the outer ring of the first bearing 4 is effectively limited by the clamp spring 62, the first bearing 4 can effectively bear the axial load given by the rotating shaft 21, and the rotating shaft 21 penetrates through the clamp spring 62 and is in clearance fit with the clamp spring 62. Compared with the nut 63, the axial load that the snap spring 62 can bear is relatively small, so that a specific first limiting member can be adaptively selected according to the magnitude of the axial load borne by the first bearing 4.

As shown in fig. 2 and 4, the brushless motor for a vehicle braking system further includes an elastic member 8, the elastic member 8 abuts against an axially outer end of the second bearing 5 and the housing 1, and the axially outer end is an end away from the rotor 22. In particular, the elastic element 8 abuts against the cover 12 of the housing 1 and the axially outer end of the second bearing 5. Because the second bearing 5 only bears radial load, the assembly position of the second bearing 5 along the axial direction is limited only by the elastic piece 8, so that the second bearing 5 and the first bearing 4 are matched to jointly support the rotating shaft 21, the coaxiality of the rotor assembly 2 and the stator assembly 3 is ensured, and the uniform magnetic field gap formed between the stator assembly 3 and the rotor assembly 2 is ensured.

Specifically, the spring is a wave spring. By providing the wave spring between the second bearing 5 and the housing cover 12, the wave spring can be in contact with both the inner race of the second bearing 5 and the outer race of the second bearing 5, thereby defining the assembly position of the second bearing 5 in the axial direction.

As shown in fig. 2, the brushless motor for a vehicle braking system further includes a sealing cover 9, the housing 1 is provided with a slot 111, and the sealing cover 9 is clamped in the slot 111. Specifically, sealed lid 9 is equipped with turn-ups 91, and casing main part 11 is equipped with draw-in groove 111, and turn-ups 91 joint is in draw-in groove 111 to prevent other materials such as water through sealed lid 9 and get into in vehicle is brushless motor's for braking system casing 1, thereby guarantee that vehicle is brushless motor for braking system can effectively work.

Specifically, the seal cover 9 is a stamped part. It can be understood that the flange 91 of the sealing cover 9 has certain elasticity, and after the sealing cover 9 is pressed on the housing main body 11, the flange 91 rebounds and is clamped in the clamping groove 111.

As shown in fig. 2, the brushless motor for a vehicle brake system further includes a first sealing ring 10, and the first sealing ring 10 is used for sealing the sealing cover 9 and the housing 1 along the axial direction of the rotating shaft 21. Thereby further preventing other substances such as water from entering the housing 1 of the brushless motor for a vehicle brake system. Specifically, the housing body 11 is further provided with a second groove, and the first sealing ring 10 is partially embedded in the second groove and tightly abuts against the sealing cover 9 along the axial direction of the rotating shaft 21.

Specifically, the first seal ring 10 is partially embedded in the second groove in an interference manner. The first seal ring 10 is thus in close contact with the side walls and the bottom wall of the second groove, thereby further ensuring that the first seal ring 10 effectively seals the gap between the seal cover 9 and the housing body 11.

Furthermore, the number of the first sealing rings 10 is a plurality of, the housing main body 11 is provided with a plurality of second grooves at intervals along the radial direction, the first sealing rings 10 are partially embedded in the second grooves in an interference manner in a one-to-one correspondence manner, and the first sealing rings 10 are all abutted against the sealing cover 9 along the axial direction of the rotating shaft 21. So configured to form a redundant seal. It will be appreciated that even if one of the first sealing rings 10 fails, the other first sealing rings 10 will effectively seal the gap between the sealing cap 9 and the housing 1.

As shown in fig. 2, the brushless motor for a vehicle brake system further includes a plug assembly 20, the plug assembly 20 includes a terminal block 201 and an adapter 202 adapted to be plugged into the terminal block 201, the terminal block 201 is used for electrically connecting with the stator assembly 3, and the adapter 202 is used for electrically connecting with a controller. When the wiring board 201 and the adapter 202 are plugged, the controller is electrically connected with the brushless motor for the vehicle brake system, so that the controller controls the rotor 22 of the brushless motor to rotate to drive the screw rod to rotate, and the screw nut screwed on the screw rod is driven to move back and forth along the axial direction.

Specifically, as shown in fig. 2, the terminal board 201 is provided with an electrical plug 2011, the adapter 202 is provided with a slot 2021, and the electrical plug 2011 is plugged into the slot 2021. By the arrangement, the connection and disconnection between the brushless motor and the controller can be controlled by controlling whether the adapter 202 is plugged in the wiring board 201; meanwhile, the distance between the controller and the wiring board 201 is adjusted by adjusting the plugging depth of the electrical plug 2011 plugged into the slot 2021, so that the interface end of the controller is not limited by the position of the wiring board 201.

Further, as shown in fig. 2, the adapter 202 is provided with a PIN 2022, and when the electrical plug 2011 is plugged into the socket 2021, the PIN 2022 is electrically connected to the electrical plug 2011.

Further, the adapter 202 and the PIN 2022 are integrally formed. The PIN 2022 is prevented from loosening or falling off the adapter 202. Wherein, a plurality of PIN needles 2022 are arranged on the adapter 202 at intervals. In this embodiment, three PIN PINs 2022 are provided at intervals on the adapter 202.

The housing cover 12 has a through hole, and the wiring board 201 passes through the through hole and is inserted into the slot 2021 of the adapter 202. Wherein, be equipped with second sealing washer 2023 on the adapter 202, second sealing washer 2023 is used for sealing up the junction of adapter 202 and controller, prevents that gasified brake fluid from getting into in the controller.

The utility model also provides a vehicle braking system, including lead screw, screw nut, piston and brake master cylinder, the lead screw spiro union is in screw nut, and the screw nut transmission is connected in the piston, and screw nut drives piston and brake master cylinder sliding connection, still includes foretell vehicle braking system and uses brushless motor, lead screw fixed connection in pivot 21. Specifically, the rotating shaft 21 drives the screw rod to rotate, so as to drive a screw nut screwed on the screw rod to reciprocate along the axial direction, the screw nut drives a piston to slide in a cylinder body of the brake master cylinder to push hydraulic oil in the brake master cylinder, and the hydraulic oil is conveyed to four wheel cylinder calipers of the vehicle, so that the braking function of the vehicle is realized.

It is to be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (10)

1. A brushless motor for a vehicle braking system, comprising a housing (1), a rotor assembly (2) and a stator assembly (3), wherein the stator assembly (3) and the rotor assembly (2) are both disposed in the housing (1), the rotor assembly (2) comprises a rotating shaft (21) and a rotor (22) disposed at the rotating shaft (21), and is characterized by further comprising:

a first bearing (4) provided between the rotating shaft (21) and the housing (1);

and the second bearing (5) is arranged between the rotating shaft (21) and the shell (1), and the first bearing (4) and the second bearing (5) are arranged on two axial sides of the stator assembly (3) at intervals.

2. The brushless motor for a vehicle brake system according to claim 1, further comprising a first limit structure and a second limit structure respectively located on both axial sides of the first bearing (4).

3. The brushless motor for a vehicle brake system according to claim 2, wherein the first limit structure includes a first limit surface (61) formed on the rotating shaft (21), the second limit structure includes a second limit surface (7) provided in the housing (1), and both axial ends of the first bearing (4) abut against the first limit surface (61) and the second limit surface (7), respectively.

4. The brushless motor for a vehicle brake system according to claim 2, wherein the first limit structure includes a first limit member connected to the housing (1), the second limit structure includes a second limit surface (7) provided in the housing (1), and both ends of the first bearing (4) in the axial direction abut against the first limit member and the second limit surface (7), respectively.

5. The brushless motor for a vehicle brake system according to claim 4, wherein the first stopper is a snap spring (62) that is snapped into the housing (1); or the first limiting piece is a nut (63) screwed with the shell (1).

6. The brushless motor for a vehicle brake system according to claim 1, further comprising an elastic member (8), wherein the elastic member (8) abuts against an axially outer end of the second bearing (5) and the housing (1), the axially outer end being an end away from the rotor (22).

7. The brushless motor for the vehicle brake system according to claim 1, further comprising a sealing cover (9), wherein the housing (1) is provided with a locking groove (111), and the sealing cover (9) is locked to the locking groove (111).

8. The brushless motor for a vehicle brake system according to claim 7, further comprising a first seal ring (10), the first seal ring (10) being for sealing the seal cover (9) and the housing (1) in an axial direction of the rotating shaft (21).

9. The brushless motor for the vehicle braking system according to claim 1, further comprising a plug assembly (20), wherein the plug assembly (20) comprises a terminal block (201) and an adapter (202) adapted to be plugged with the terminal block (201), wherein the terminal block (201) is used for being electrically connected with the stator assembly (3), and wherein the adapter (202) is used for being electrically connected with a controller.

10. A vehicle braking system, comprising a lead screw, a lead screw nut, a piston and a brake master cylinder, wherein the lead screw is screwed on the lead screw nut, the lead screw nut is in transmission connection with the piston, the lead screw nut drives the piston to be in sliding connection with the brake master cylinder, the vehicle braking system is characterized by further comprising the brushless motor for the vehicle braking system according to any one of claims 1 to 9, and the lead screw is fixedly connected with the rotating shaft (21).

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