Low-cost full-load motor

Abstract

The invention discloses a low-cost full-load motor which comprises a rotor, a stator and a hollow rotating shaft, the hollow rotating shaft is arranged on the rotor through a rotor hub and used for transmitting torque, a bearing assembly is arranged between the hollow rotating shaft and the stator in the axial direction, and floating end bearings and fixed end bearings of the assembly are arranged at intervals in the axial direction of the hollow rotating shaft. And the hollow rotating shaft is axially positioned relative to the bearing seat by the fixed end bearing supporting point. The floating end bearing supporting point can bear axial displacement generated when the distance between the two bearings is changed due to thermal expansion of the hollow rotating shaft relative to the bearing seat, and the accumulated tolerance of components influencing the distance between the two bearings is made up. The problems that a conventional motor is high in manufacturing cost, tedious in assembly and troublesome in maintenance are solved. Besides, the motor has a full-bearing function, the output end of the motor can be connected with a load end with any load direction change and operates stably, the load end does not need to be connected after a bearing structure is switched over, and the problems of large occupied space and high weight are solved.

Description

Technical Field

[0001] The invention relates to a motor for a helicopter rotor, and in particular to a design of an appearance, an interface and an internal structure of a motor for an unmanned helicopter rotor. Background Art

[0002] The motors conventionally used in helicopter rotor systems only provide torque as a power source and do not participate in load-bearing. When driving the rotor structure to rotate, other external structures are required to carry and transmit torque. As a rotor motor, when the rotor speed changes during the operation of the helicopter, the rotor shaft will be subjected to the complex aerodynamic forces exerted on the rotor. For the rotor shaft, the forces exerted can be decomposed into bidirectional axial forces, bending moments and torques. In order to deal with this situation, there are two solutions on the market. The first is a solution of motor, other structures and rotor structure. The motor of this solution contains a pair of deep groove ball bearings, which can only output torque, and then the rotor system is connected and loaded through the support of the other structures. In addition to the motor structure, this solution also has other structures, so the solution occupies a large space, is heavy and has high cost. The second is the motor plus rotor structure solution. The motor of this solution contains a pair of angular contact ball bearings, which can not only output torque, but also bear bidirectional axial loads. Compared with the first solution, no other structures are required. However, when assembling the angular contact ball bearings of the motor, the overall clearance of the bearing group must be controlled. Otherwise, when carrying an axial load in a certain direction during operation, the other angular contact ball bearing that is not subject to the axial load may have excessive clearance, resulting in the bearing. In addition to pre-tightening by customizing springs, it is also necessary to control the machining accuracy and use high-precision gaskets of different thicknesses to affect the clearance and ensure that it is controlled within the ideal bearing clearance range. In the process of mass production of motors, this process is extremely time-consuming, so the entire process will incur additional manufacturing, assembly, and maintenance costs.

[0003] In order to solve these problems caused by conventional motors driving helicopter rotor systems, it is necessary to design a motor that can connect to the load end with any load direction change and operate stably, while also ensuring the requirements of reducing weight, being easy to use, safe and reliable, and reducing costs. Summary of the invention

[0004] In view of this, the present invention provides a low-cost full-load motor. In view of this, the purpose of the present invention is to provide a structural scheme that can be used for an unmanned helicopter rotor motor. The structural scheme has a simple structure, small size and light weight, low manufacturing cost, and can be connected to load ends with any load direction changes and operate stably.

[0005] The present invention provides a low-cost full-load motor adopts the following technical solution:

[0006] A low-cost full-load motor comprises a rotor, a stator and a hollow shaft, wherein the hollow shaft is arranged on the rotor through a rotor hub for transmitting torque, a bearing assembly is axially arranged between the hollow shaft and the stator, and a floating end bearing and a fixed end bearing of the assembly are arranged axially at intervals along the hollow shaft.

[0007] Optionally, the floating end bearing is arranged close to the output end of the hollow shaft.

[0008] Optionally, a bearing capable of withstanding axial displacement is arranged between the inner ring and the outer ring of the floating end bearing, or a bearing with a clearance fit is adopted between one of the inner ring and the outer ring and the mating surface, and the fixed end bearing can axially position the hollow shaft relative to the bearing seat.

[0009] Optionally, a shaft ring is arranged between the floating end bearing and the fixed end bearing.

[0010] Optionally, a locking member is also included, which is arranged on the hollow rotating shaft and pressed against the fixed end bearing.

[0011] Optionally, the stator is provided with a bearing seat end cover, and the bearing seat end cover is located on one side of the rotor and has a channel, and the channel is arranged in a maze.

[0012] Optionally, a rotor hub is provided on the rotor, and a centering step is provided between the rotor and the rotor hub.

[0013] Optionally, a second centering step is provided between the stator and the outer bearing seat and the inner bearing seat.

[0014] Optionally, a centering step three is provided between the bearing end cover and the outer bearing seat, and a centering step four for mounting the motor is provided on the bearing seat end cover.

[0015] Optionally, fasteners are provided on the inner bearing seat, and the fasteners are used to fix the inner bearing seat, the rotor, the outer bearing seat, the stator, the bearing seat end cover, and the fixed end bearing together.

[0016] In summary, the present invention includes at least one of the following beneficial technical effects: It solves the problems of high manufacturing cost, complicated assembly and troublesome maintenance of conventional motors. In addition, the motor has a full load-bearing function, and its output end can be connected to the load end with any load direction change and operate stably, without the need to transfer the load structure and then connect the load end, which solves the problem of large space occupation and high weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a side sectional view of an embodiment of the present invention;

[0018] Figure 2Schematic diagram of the assembly of the embodiment of the present invention Figure 1 ;

[0019] Figure 3 Schematic diagram of the assembly of the embodiment of the present invention Figure 2 ;

[0020] Figure 4 Schematic diagram of the assembly of the embodiment of the present invention Figure 3 .

[0021] Explanation of the reference numerals in the accompanying drawings: 1. rotor hub; 2. hexagon socket cylindrical head screw; 3. locking thin nut; 4. flat washer; 5. B-type flat key; 6. hollow shaft; 7. floating end bearing; 8. inner bearing seat; 9. hexagon socket short cylindrical head screw; 10. rotor; 11. stator; 12. outer bearing seat; 13. F-type precision locking nut; 14. bearing seat end cover; 15. fixed end bearing; 16. shaft collar. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1-4 The present invention is described in further detail.

[0023] The embodiment of the present invention discloses a low-cost fully-loaded motor.

[0024] Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 A low-cost full-load motor comprises a rotor 10, a stator 11 and a hollow shaft 6. The hollow shaft 6 is arranged on the rotor 10 through a rotor hub 1 for transmitting torque. A bearing assembly is arranged axially between the hollow shaft 6 and the stator 11. The bearing assembly comprises a floating end bearing 7 and a fixed end bearing 15. The floating end bearing 7 and the fixed end bearing 15 are arranged at intervals along the axial direction of the hollow shaft 6. The support point of the fixed end bearing 15 axially positions the hollow shaft 6 relative to the bearing seat. The support point of the floating end bearing 7 can withstand the axial displacement caused by the change of the distance between the two bearings due to the thermal expansion of the hollow shaft 6 relative to the bearing seat, and compensate for the accumulated tolerance of the components that affect the distance between the two bearings. The above content solves the problems of high manufacturing cost, cumbersome assembly and troublesome maintenance of conventional motors. In addition, the motor has a full-load function, and its output end can be connected to the load end with any load direction change and run stably, without the need to transfer the load structure and then connect the load end, solving the problems of large space occupation and high weight.

[0025] The floating end bearing 7 is arranged near the output end of the hollow rotating shaft 6. The floating end bearing is a bearing that can withstand axial displacement between the inner and outer rings of the bearing. For example, a cylindrical roller bearing with a rib on only one ring. Or a bearing with a clearance fit between one of the bearing rings and the mating surface. In this embodiment, a deep groove ball bearing is used.

[0026] The outer ring of the floating end bearing 7 and the matching surface on the inner bearing seat are clearance matched to form a floating end that can withstand axial displacement. The outer ring of the fixed end bearing 15 is provided with an outer bearing seat 12 and a bearing seat end cover 14 to form a fixed end with axial positioning function. When the hollow shaft 6 is subjected to an axial load in any direction, the internal clearance of the fixed end bearing 15 changes and bears the axial load, while the clearance matching surface of the floating end bearing 7 will be slightly displaced in the axial direction, and the axial load will be unloaded at the same time, avoiding the floating end bearing from participating in the axial load and causing damage.

[0027] A shaft collar is arranged between the floating end bearing 7 and the fixed end bearing 15, and is tightened with a locking nut. By arranging the shaft collar between the two bearings, not only can the two bearings be supported, but also a force arm is formed. When the output end of the hollow shaft 6 is subjected to a bending moment caused by the load end, the floating end bearing 7 is used as a fulcrum, and the floating end bearing 7 and the fixed end bearing 15 can effectively share the radial load.

[0028] Since the fixed end bearing 15 is a high-precision standard part, the clearance standard is qualified and no additional clearance adjustment is required. With the fixed / floating bearing configuration structure, the step of manually adjusting the distance between the two bearings and the bearing clearance during assembly is eliminated, thereby reducing the machining accuracy requirements for motor parts and making it more convenient to mass-produce motors with this structural solution. The fixed end bearing support point axially positions the hollow shaft relative to the bearing seat. In this embodiment, a double-row angular contact ball bearing is used.

[0029] The motor 100 also includes a locking member, which is arranged on the hollow rotating shaft 6 and pressed against the fixed end bearing 15, so as to fix the motor as a whole and prevent it from loosening. In this example, the locking member adopts an F-type precision locking nut 13.

[0030] The stator 11 is provided with a bearing seat end cover 14, and the bearing seat end cover 14 is located on one side of the rotor 10 and has a channel, and the channel adopts a maze setting. In this embodiment, the maze setting means that the channel has certain regular bends similar to a maze, which has a dust-proof effect.

[0031] A rotor hub 1 is provided on the rotor 10 , and a flat key is provided between the rotor hub 1 and the hollow shaft 6 . The flat key is a B-type flat key 5 , which transmits the power of the rotor hub 1 to the hollow shaft 6 .

[0032] A centering step 1 is provided between the rotor 10 and the rotor hub 1. By providing the centering step 1, the hollow shaft 6 on the rotor hub 1 can be located at the axial center of the rotor 10 during assembly, thereby achieving rapid assembly without the need for additional auxiliary positioning.

[0033] Similarly, a centering step 2 is provided between the stator 11 and the outer bearing seat 12 and the inner bearing seat 8. This facilitates the subsequent rapid assembly of the stator 11 and the outer bearing seat 12 and the inner bearing seat 8, and is easy to install.

[0034] Similarly, a centering step three is provided between the bearing seat end cover 14 and the outer bearing seat 12, and a centering step four is also provided on the bearing seat end cover 14, so as to facilitate subsequent quick assembly and installation.

[0035] The inner bearing seat 8 is provided with fasteners, which are used to fix the inner bearing seat 8, the rotor 10, the outer bearing seat 12, the stator 11, the bearing seat end cover 14, and the fixed end bearing 15. The fasteners are hexagon socket head screws 2, locking thin nuts 3 and flat washers 4.

[0036] The rotor 10 and the rotor hub 1 are fixed together by bolts. A hollow shaft 6 passes through the middle of the rotor hub 1, and a pair of flat keys are contained between them. The bearing seat end cover 14 on the stator 11 has a motor mounting hole, and the motor is fixed first. When the inner stator 11 is powered on to drive the rotor 10 to rotate, the hollow shaft 6 will rotate synchronously. The two bearings between it and the stator 11 support the stable rotation structure of the hollow shaft 6. Among them, the floating end bearing 7 close to the rotor hub 1 adopts a closed single-row deep groove ball bearing in this example, which is installed between the hollow shaft 6 and the inner bearing seat 8 on the stator 11. The bearing can only bear radial loads; the other fixed end bearing 15 is a double-row angular contact ball bearing in this example, which is installed between the hollow shaft 6 and the outer bearing seat 12 and the bearing seat end cover 14 on the stator 11, and can bear combined loads.

[0037] When the hollow shaft 6 of the motor is subjected to an axial load, the axial load is borne by the fixed end bearing 15, while the single-row deep groove ball bearing 7 is in a floating state and can be displaced on the shaft to unload the axial load; when the hollow shaft 6 is bent, the bending moment acts on the support points formed by the two bearings, and the radial load caused is borne by the two bearings. Therefore, the motor structure has a stable and reliable full-load performance.

[0038] The structure is easy to assemble. Figure 2 and Figure 3 , and then let Figure 1 and Figure 2 Combined together, under the guidance of the tooling, the inner bearing seat 8 can smoothly slide onto the floating end bearing 7, and the inner ring of the fixed end bearing 15 can also smoothly slide onto the hollow shaft 6 at the same time, because they are all clearance fit. Figure 4 The F-type precision locking nut 13 can be screwed in and tightened, which is easy to install. Since all bearings are closed, they have their own sealing devices and are maintenance-free.

[0039] In other embodiments, the hollow shaft 6 can be replaced by a solid shaft.

[0040] In other embodiments, the flat key structure of the B-type flat key may be replaced with a spline structure.

[0041] The present invention has low cost, compact and reliable structure, easy installation and maintenance-free, and the output end can resist tension, compression, bending and shearing. The motor adopting this structural scheme can be connected to the load end with complex load conditions, and is particularly suitable as a power source to connect the rotor system of an aircraft.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A low-cost full-load motor comprises an outer rotor, an inner stator and a hollow shaft. The hollow shaft is arranged on the outer rotor through a rotor hub for transmitting torque. A bearing assembly is axially arranged between the hollow shaft and the inner stator. The floating end bearing and the fixed end bearing of the assembly are arranged axially at intervals along the hollow shaft.

2. A low-cost fully loaded motor according to claim 1, characterized in that: The floating end bearing is arranged close to the output end of the hollow rotating shaft.

3. A low-cost fully loaded motor according to claim 1, characterized in that: A bearing capable of withstanding axial displacement is arranged between the inner ring and the outer ring of the floating end bearing, or a bearing with clearance fit is adopted between one of the inner ring and the outer ring and the mating surface, and the fixed end bearing can axially position the hollow shaft relative to the bearing seat.

4. A low-cost fully loaded motor according to claim 1, characterized in that: A shaft ring is arranged between the floating end bearing and the fixed end bearing.

5. A low-cost fully loaded motor according to claim 1, characterized in that: It also includes a locking piece, which is arranged on the hollow rotating shaft and pressed against the fixed end bearing.

6. A low-cost fully loaded motor according to claim 1, characterized in that: The stator is provided with a bearing seat end cover, and the bearing seat end cover is located on one side of the rotor and has a channel, and the channel is arranged in a labyrinth.

7. A low-cost fully loaded motor according to claim 1, characterized in that: A rotor hub is arranged on the rotor, and a centering step 1 is arranged between the rotor and the rotor hub.

8. A low-cost fully loaded motor according to claim 7, characterized in that: A second centering step is arranged between the stator and the outer bearing seat and the inner bearing seat.

9. A low-cost fully loaded motor according to claim 6, characterized in that: A third centering step is provided between the bearing end cover and the outer bearing seat, and a fourth centering step for mounting the motor is provided on the bearing seat end cover.

10. A low-cost fully loaded motor according to claim 2, characterized in that: The inner bearing seat is provided with fasteners, and the fasteners are used to fix the inner bearing seat, the rotor, the outer bearing seat, the stator, the bearing seat end cover and the fixed end bearing together.

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