Brushless direct current motor

Abstract

The invention provides a brushless direct current motor, and belongs to the technical field of aviation motors, the brushless direct current motor specifically comprises a shell, a front end cover, a rear end cover, a rotor and a stator, the front end cover is installed at one end of the shell, the rear end cover is installed at the other end of the shell, and a rotating shaft of the rotor is rotatably connected with the front end cover through a front bearing; a rotating shaft of the rotor is rotationally connected with the rear end cover through a rear bearing, and the shell, the front end cover and the rear end cover are all made of metal materials; the front end cover is provided with a first socket, the first socket is electrically connected with a twisted-pair shielding wire, the first socket is fixedly connected with the front end cover through the shielding wire, the front end cover is provided with a mounting hole for mounting the first socket, and one end, far away from the rear end cover, of the first socket is located in the mounting hole; the inner wall of the housing is provided with a threading groove, and the twisted-pair shielding wire is led out from the first socket, passes through the threading groove, and then is led to the rear end cover. According to the processing scheme, the weight of the motor is reduced, and the shielding performance and the high temperature resistance of the motor are improved.

Description

Technical Field

[0001] The present application relates to the field of electric motors for aviation, and in particular to a brushless DC motor. Background Art

[0002] During long taxiing phases, aircraft may frequently brake, causing the brake system to overheat. In severe cases, this can lead to a fire in the fan brake system. Brake cooling fans are typically used to reduce the temperature. Brake cooling fans consist of a brake drive motor and fan blades. According to the main engine requirements, this drive motor should meet the requirements of a Φ100×232 dimension, an output power of 510W, and a rated speed of 7850rpm. Existing electric motors are heavy, bulky, and poorly shielded. Summary of the Invention

[0003] In view of this, the present application provides a brushless DC motor that solves the problems in the prior art, reduces the weight of the motor, and improves the shielding and high temperature resistance of the motor.

[0004] The brushless DC motor provided in this application adopts the following technical solution:

[0005] A brushless DC motor comprises a housing, a front end cover, a rear end cover, a rotor, and a stator. The front end cover is mounted on one end of the housing, and the rear end cover is mounted on the other end of the housing. The rotor shaft is rotatably connected to the front end cover via a front bearing, and the rotor shaft is rotatably connected to the rear end cover via a rear bearing. The housing, the front end cover, and the rear end cover are all made of metal.

[0006] The front cover is provided with a first socket, the first socket is electrically connected to a twisted shielded pair wire, the first socket is fixedly connected to the front cover through the shielded wire, the front cover is provided with a mounting hole for mounting the first socket, and an end of the first socket away from the rear cover is located in the mounting hole;

[0007] A wire threading groove is provided on the inner wall of the shell, and the twisted shielded pair wires are led out from the first socket, pass through the wire threading groove, and then lead to the rear end cover.

[0008] Optionally, the rear end cover and the front end cover are made of aluminum alloy, the front bearing and the rear bearing are made of stainless steel, the front end cover and the rear end cover are provided with holes for the rotating shaft to pass through, steel sleeves are interference-pressed in the holes, the front bearing is installed in the steel sleeve of the front end cover, and the rear bearing is installed in the steel sleeve of the rear end cover.

[0009] Optionally, slotted countersunk screws are installed on the mating surfaces of the inner wall of the hole and the outer wall of the steel sleeve, and the length direction of the slotted countersunk screws is parallel to the length direction of the rotating shaft.

[0010] Optionally, the shell is made of aluminum alloy, and the shell and stator are pressed into the shell by heat assembly. The side wall of the shell is provided with a plurality of slotted cone-end set screws evenly distributed along the circumference, and the slotted cone-end set screws pass through the side wall of the shell and are tightened against the outer ring of the stator. The end surface of the shell and the front end cover and the end surface of the shell and the rear end cover are both provided with slots, and a wire screw sleeve is fixed in the slot. The shell and the front end cover are fixedly connected by a fastening screw threadedly connected to the wire screw sleeve, and the shell and the rear end cover are fixedly connected by a fastening screw threadedly connected to the wire screw sleeve, and the wire screw sleeve is made of stainless steel.

[0011] Optionally, the rear bearing is a ball bearing, and a boss is provided in the steel sleeve of the rear end cover. The boss is located on the side of the rear bearing facing away from the front end cover, and the boss and the rear bearing bracket are provided with a butterfly spring surrounding the outer circumference of the rotating shaft.

[0012] Optionally, the rotating shaft is made of titanium alloy, and a weight-reducing center hole is provided in the end of the rotating shaft close to the rear end cover.

[0013] Optionally, the rotor includes a rotor core, a magnet, a dynamic balance ring, and a rotor sleeve. The rotor core is arranged on the outer periphery of the rotating shaft, the magnet surrounds the outer periphery of the rotor core, and the rotor sleeve is arranged on the outer periphery of the magnet. The dynamic balance ring is fixed at both ends of the rotor core, the dynamic balance ring and the rotating shaft are connected by threads, and adhesive is filled between the dynamic balance ring and the rotating shaft.

[0014] Optionally, the magnetic steel is SmCo28 magnetic steel.

[0015] In summary, this application has the following beneficial technical effects:

[0016] The present application provides shielding of the motor through the design of the first socket of the front end cover, while reducing the weight of the motor casing and rotor while improving the strength and stability of the connection between the various components. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 For this application, a brushless DC motor;

[0019] Figure 2 This is a structural diagram of the rear end cover of this application;

[0020] Figure 3This is a schematic structural diagram of the shell of this application;

[0021] Figure 4 This is a schematic diagram of the structure of the stator of this application;

[0022] Figure 5 This is a schematic diagram of the structure of the rotor of this application.

[0023] Explanation of the accompanying reference numerals: 1. Housing; 11. Slotted tapered end set screw; 12. Wire thread sleeve; 2. Front end cover; 21. Front bearing; 22. First socket; 3. Rear end cover; 31. Rear bearing; 32. Butterfly spring; 33. Second socket; 4. Steel sleeve; 41. Slotted countersunk screw; 42. Boss; 43. Sleeve; 5. Stator; 51. Coil; 52. Stator end piece; 53. Slot wedge; 54. Stator core; 6. Rotor; 61. Rotating shaft; 62. Dynamic balancing ring; 63. Rotor sleeve; 64. Magnet; 65. Rotor core; 65. Adhesive; 7. Sensor back cover. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0025] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0026] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0027] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0028] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples. However, one skilled in the art will appreciate that the aspects described can be practiced without these specific details.

[0029] An embodiment of the present application provides a brushless DC motor.

[0030] like Figure 1 As shown, a brushless DC motor includes a housing 1, a front end cover 2, a rear end cover 3, a rotor 6 and a stator 5. The front end cover 2 is installed at one end of the housing 1, and the rear end cover 3 is installed at the other end of the housing 1. The rotating shaft 61 of the rotor 6 is rotatably connected to the front end cover 2 through a front bearing 21, and the rotating shaft 61 of the rotor 6 is rotatably connected to the rear end cover 3 through a rear bearing 31. The housing 1, the front end cover 2 and the rear end cover 3 are all made of metal.

[0031] The front end cover 2 is provided with a first socket 22, to which a twisted shielded pair wire is electrically connected. The first socket 22 is fixedly connected to the front end cover 2 through the shielded wire. The front end cover 2 is provided with a mounting hole for mounting the first socket 22, and one end of the first socket 22 away from the rear end cover 3 is located in the mounting hole; the speed sensor is used to transmit signals, and the shielding layer is connected to the rectangular socket pin for grounding, so as to prevent the speed signal from being interfered with by the electrical signal during transmission.

[0032] In the embodiment of the present application, the line voltage of the brushless DC motor is 270V, and the speed is 7850rpm under a load of 0.7Nm.

[0033] The inner wall of the housing 1 is provided with a threading groove, and the twisted shielded pair wire is led out from the first socket 22 through the threading groove and then led to the rear end cover 3. The lead wire of the first socket 22 passes through the threading groove inside the housing 1, which can reduce the volume of the entire motor.

[0034] The rear end cover 3 is provided with a second socket 33 , which is a J599 III series electrical connector resistant to salt spray and hot and humid environments.

[0035] like Figure 1 and Figure 2As shown, the rear end cover 3 and front end cover 2 are made of aluminum alloy, and the front bearing 21 and rear bearing 31 are made of stainless steel. The front end cover 2 and rear end cover 3 are provided with holes for the rotation shaft 61 to pass through. A steel sleeve 4 is press-fitted into the holes. The front bearing 21 is mounted within the steel sleeve 4 of the front end cover 2, and the rear bearing 31 is mounted within the steel sleeve 4 of the rear end cover 3. The aluminum alloy rear end cover 3 and front end cover 2 effectively reduce the weight of the motor. The steel sleeve 4, which serves as a bearing mounting chamber between the end cover and the bearing, is designed to improve machining accuracy and mechanical strength and reduce the effects of high-temperature thermal expansion on the bearing. A slotted countersunk screw 41 is punched and installed on the mating surface of the inner wall of the hole and the outer wall of the steel sleeve 4. The mating surface of the front end cover 2 and the steel sleeve 4 and the slotted countersunk screw 41 on the front end cover 2 are threadedly connected. The mating surface of the rear end cover 3 and the steel sleeve 4 and the slotted countersunk screw 41 on the front end cover 2 are threadedly connected to increase the installation strength of the connecting steel sleeve 4. The length direction of the slotted countersunk screw 41 is parallel to the length direction of the rotating shaft 61. Among them, the slotted countersunk screw 41 at the front end cover 2 enters from one side of the outer surface of the front end cover 2 and is threadedly connected to the steel sleeve 4. The steel sleeve 4 of the rear end cover 3 is provided with a boss 42 on the outer periphery of the end near the front end cover 2. The rear end cover 3 is provided with a sleeve 43 surrounding the outer periphery of the steel sleeve 4. The boss 42 overlaps the end surface of the sleeve 43 facing the front end cover 2. The slotted countersunk screw 41 at the rear end cover 3 passes through the boss 42 and is threadedly connected to the sleeve 43. The inner side of the sleeve 43 and the outer wall of the steel sleeve 4 are each provided with a semicircular thread groove. The two semicircular thread grooves are connected to form a whole threaded hole that cooperates with the slotted countersunk screw 41. During the processing, after the steel sleeve 4 and the sleeve 43 of the rear end cover 3 are press-fitted by interference fit, the inner diameter of the sleeve 43 is machined again with the rear end cover 3 as the positioning to ensure the coaxiality of the two and the verticality of the bearing chamber, thereby improving the fitting accuracy.

[0036] like Figure 1 and Figure 3As shown, the housing 1 is made of aluminum alloy. The housing 1 and stator 5 are press-fitted into the housing 1 by heat-fitting. The sidewalls of the housing 1 are provided with a number of slotted, tapered-end set screws 11 evenly distributed along the circumference. These slotted, tapered-end set screws 11 penetrate the sidewalls of the housing 1 and abut against the outer ring of the stator 5. The end faces of the housing 1 and the front end cover 2, as well as the end faces of the housing 1 and the rear end cover 3, are both provided with slots. Wire screw inserts 12 are fixed in these slots. The housing 1 and the front end cover 2 are fixedly connected by fastening screws threadedly connected to the wire screw inserts 12. The housing 1 and the rear end cover 3 are fixedly connected by fastening screws threadedly connected to the wire screw inserts 12. The wire screw inserts 12 are made of stainless steel. The aluminum alloy housing 1 can reduce the weight of the entire motor. The slotted, tapered-end set screws 11 are used to limit the axial displacement of the stator 5. Moreover, the wire thread sleeve on the housing 1 is made of stainless steel, which improves the bearing capacity and fatigue strength of the screw connection and can strengthen the stable connection between the housing 1 and the front cover 2 and the rear cover 3.

[0037] In one embodiment, the outer side of the rear end cover 3 is fixed with a sensor rear cover by screws, and a wire screw sleeve 12 is provided on the outer side of the rear end cover 3 .

[0038] The rear bearing 31 is a ball bearing. A boss 42 is provided within the steel sleeve 4 of the rear end cover 3. The boss 42 is located on the side of the rear bearing 31 facing away from the front end cover 2. A butterfly spring 32 is provided between the boss 42 and the bracket of the rear bearing 31, surrounding the outer circumference of the rotating shaft 61. The butterfly spring 32 increases the axial preload of the rear bearing 31 and limits its axial displacement.

[0039] like Figure 4 As shown, the stator 5 is composed of a coil 51, slot wedges 53, and a stator core 54. The stator core 54 is composed of stator laminations and stator end plates 52. The stator laminations are laminated and bonded together and then fixed by laser welding to improve mechanical strength. In one embodiment, the stator laminations are composed of stator lamination slots and laser welding slots. The number of stator lamination slots is 12 and they are evenly distributed in an annular pattern. The slots are pear-shaped with oblique shoulders, with a slot width of 2 mm, a slot height of 0.5 mm, a slot shoulder width of 6.5 mm, a slot shoulder height of 1.5 mm, a slot depth of 13 mm, and a slot bottom radius of 1.5 mm. By reducing the height and width of the slots, the stator 5 adopts a structure with a small slot height and width, effectively improving product efficiency.

[0040] The rotating shaft 61 is made of titanium alloy, and a weight-reducing center hole is provided in the end of the rotating shaft 61 close to the rear end cover 3. The length of the weight-reducing center hole accounts for half of the total length of the rotating shaft 61, which can effectively reduce the weight of the rotating shaft 61.

[0041] like Figure 5As shown, the rotor 6 includes a rotor core 65, a magnet 64, a dynamic balance ring 62, and a rotor sleeve 63. The rotor core 65 is arranged on the outer periphery of the rotating shaft 61, the magnet 64 surrounds the outer periphery of the rotor core 65, and the rotor sleeve 63 is sleeved on the outer periphery of the magnet 64. The dynamic balance ring 62 is fixed to both ends of the rotor core 65. The dynamic balance ring 62 and the rotating shaft 61 are connected by threads, and the space between the dynamic balance ring 62 and the rotating shaft 61 is filled with adhesive 66 to improve the connection tightness. The magnet 64 is SmCo28 magnet and can withstand high temperatures of 300°C. In addition, there is a V-shaped groove in the middle of the dynamic balance ring 62 to facilitate positioning during deweighting.

[0042] In one embodiment, the stator core 54 has an outer diameter of 76 mm, an inner diameter of 42 mm, and a core length of 14 mm, while the rotor core 65 has an outer diameter of 40.6 mm, an inner diameter of 22 mm, and a core length of 16 mm. Practice has shown that this combination of stator and rotor cores 65 can effectively improve product efficiency.

[0043] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A brushless DC motor, comprising a housing (1), a front end cover (2), a rear end cover (3), a rotor (6) and a stator (5), wherein the front end cover (2) is mounted on one end of the housing (1), and the rear end cover (3) is mounted on the other end of the housing (1), a rotating shaft (61) of the rotor (6) is rotatably connected to the front end cover (2) via a front bearing (21), and a rotating shaft (61) of the rotor (6) is rotatably connected to the rear end cover (3) via a rear bearing (31), characterized in that: The housing (1), the front end cover (2) and the rear end cover (3) are all made of metal; The front end cover (2) is provided with a first socket (22), the first socket (22) is electrically connected to a twisted pair shielded wire, the first socket (22) is fixedly connected to the front end cover (2) via the shielded wire, the front end cover (2) is provided with a mounting hole for mounting the first socket (22), and one end of the first socket (22) away from the rear end cover (3) is located in the mounting hole; The inner wall of the housing (1) is provided with a wire threading groove, and the twisted shielded pair wire is led out from the first socket (22) through the wire threading groove and then led to the rear end cover (3).

2. The brushless DC motor according to claim 1, characterized in that: The rear end cover (3) and the front end cover (2) are made of aluminum alloy, the front bearing (21) and the rear bearing (31) are made of stainless steel, the front end cover (2) and the rear end cover (3) are provided with holes for the rotating shaft (61) to pass through, a steel sleeve (4) is press-fitted into the holes, the front bearing (21) is installed in the steel sleeve (4) of the front end cover (2), and the rear bearing (31) is installed in the steel sleeve (4) of the rear end cover (3).

3. The brushless DC motor according to claim 2, characterized in that: A slotted countersunk screw (41) is installed by drilling holes on the matching surfaces of the inner wall of the hole and the outer wall of the steel sleeve (4), and the length direction of the slotted countersunk screw (41) is parallel to the length direction of the rotating shaft (61).

4. The brushless DC motor according to claim 1, characterized in that: The shell (1) is made of aluminum alloy. The shell (1) and the stator (5) are press-fitted into the shell (1) by heat assembly. The side wall of the shell (1) is provided with a plurality of slotted cone-end set screws (11) evenly distributed along the circumference. The slotted cone-end set screws (11) pass through the side wall of the shell (1) and are pressed against the outer ring of the stator (5). The end surface of the shell (1) and the front cover (2) and the end surface of the shell (1) and the rear cover (3) are both provided with slots. A wire screw sleeve (12) is fixed in the slot. The shell (1) and the front cover (2) are fixedly connected by a set screw threadedly connected to the wire screw sleeve (12). The shell (1) and the rear cover (3) are fixedly connected by a set screw threadedly connected to the wire screw sleeve (12). The wire screw sleeve (12) is made of stainless steel.

5. The brushless DC motor according to claim 4, characterized in that: The rear bearing (31) is a ball bearing. A boss (42) is provided in the steel sleeve (4) of the rear end cover (3). The boss (42) is located on the side of the rear bearing (31) facing away from the front end cover (2). The boss (42) and the rear bearing (31) bracket are provided with a butterfly spring (32) surrounding the outer circumference of the rotating shaft (61).

6. The brushless DC motor according to claim 1, characterized in that: The rotating shaft (61) is made of titanium alloy, and a weight-reducing center hole is provided in the end of the rotating shaft (61) close to the rear end cover (3).

7. The brushless DC motor according to claim 1, characterized in that: The rotor (6) comprises a rotor core (65), a magnetic steel (64), a dynamic balancing ring (62), and a rotor sleeve (63); the rotor core (65) is arranged on the outer periphery of a rotating shaft (61); the magnetic steel (64) surrounds the outer periphery of the rotor core (65); the rotor sleeve (63) is sleeved on the outer periphery of the magnetic steel (64); the dynamic balancing ring (62) is fixed to both ends of the rotor core (65); the dynamic balancing ring (62) and the rotating shaft (61) are connected by threads; and adhesive (66) is filled between the dynamic balancing ring (62) and the rotating shaft (61).

8. The brushless DC motor according to claim 7, characterized in that: The magnetic steel (64) is SmCo28 magnetic steel.

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