CN113517789A

CN113517789A - Switched reluctance motor for garden tool

Info

Publication number: CN113517789A
Application number: CN202110544552.9A
Authority: CN
Inventors: 颜士伟; 池晓峰; 刘学; 张俊杰; 郑江松
Original assignee: Jiangsu Leili Motor Co Ltd
Current assignee: Jiangsu Leili Motor Co Ltd
Priority date: 2021-05-19
Filing date: 2021-05-19
Publication date: 2021-10-19

Abstract

The invention discloses a switched reluctance motor for garden tools, which comprises a front end cover, a rear end cover, a stator assembly, a controller and a heat conducting pad, wherein the inner side surface of the rear end cover is provided with a heat conducting pad mounting part; the stator assembly comprises a stator core and a coil framework arranged in the stator core, and the front end cover and the rear end cover are respectively fixed at two ends of the stator core; the controller is arranged between the stator assembly and the rear end cover; the heat conduction pad is arranged in the heat conduction pad mounting part of the rear end cover and is positioned between the rear end cover and the controller. The invention provides a switched reluctance motor for a garden tool, which solves the problems of installation and heat dissipation of a controller and meets the development trends of large motor power density, low cost, small volume and convenient movement of electric tools and garden tools.

Description

Switched reluctance motor for garden tool

Technical Field

The invention relates to a switched reluctance motor for a garden tool, and belongs to the technical field of motors.

Background

At present, most manufacturers of electric tools and garden tools use series excited motors to drive mechanical structures to rotate. As is well known, the series excited motor uses a carbon brush and a commutator, so that the life is short, the failure rate is high, and carbon brush dust pollutes the environment. And the defects that the permanent magnet direct current brushless motor is adopted by manufacturers but the price of the permanent magnet material is high and the demagnetization is easy exist. Therefore, the use of the switched reluctance motor for the garden tool is a good choice to overcome the above problems. However, compared with a system scheme of a series motor, the switched reluctance motor system scheme for the garden tool needs to solve the problems of installation and heat dissipation of the controller, and most manufacturers adopt a design scheme of separating the motor body from the controller, so that the development trend that the motor power density of the electric tool and the motor of the garden tool is large, the cost is low, the size is small, and the movement is convenient cannot be met.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides the switched reluctance motor for the garden tool, solves the problems of installation and heat dissipation of the controller, and meets the development trends of large motor power density, low cost, small volume and convenient movement of the electric tool and the garden tool.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a switched reluctance motor for a garden tool, comprising:

a front end cover;

the inner side surface of the rear end cover is provided with a heat conduction pad installation part;

the stator assembly comprises a stator core and a coil framework arranged in the stator core, and the front end cover and the rear end cover are respectively fixed at two ends of the stator core;

a controller disposed between the stator assembly and the rear end cap;

the heat conduction pad is arranged in the heat conduction pad mounting part of the rear end cover and is positioned between the rear end cover and the controller.

Further, the shape of heat conduction pad is fan-shaped, the heat conduction pad installation department is with the fan-shaped heavy groove of heat conduction pad shape adaptation, the controller includes the PCB board, installs at the positive power tube of PCB board, the one side of heat conduction pad is hugged closely with the fan-shaped heavy groove of the heat conduction pad installation department of rear end cover, the another side and the power tube of heat conduction pad are hugged closely, the fan-shaped heavy tank bottom surface of the heat conduction pad installation department of rear end cover is less than the free thickness size of heat conduction pad 0.5mm ~ 1mm to the distance of the cooling surface of power tube.

Further, the stator core comprises a plurality of stator salient poles and stator core grooves, a plurality of coil formers are arranged in the coil frame, the coil formers are wrapped on the stator salient poles, windings are wound on the coil formers, a plurality of grooves are formed in the radial outer edge of one axial end of the coil frame, puncture-type terminals which are electrically connected with the windings on the coil frame are inserted in the grooves, and each puncture-type terminal is electrically connected with the wiring end of the corresponding winding.

Furthermore, a plurality of positioning columns and a PCB supporting structure are arranged on the coil framework, the PCB supporting structure is a plurality of supporting columns arranged on the coil framework, and the supporting columns are positioned below the positioning columns; the PCB is provided with a positioning hole which is correspondingly assembled with the positioning column on the coil framework, and the PCB is arranged on the positioning column through the positioning hole and is axially supported by the supporting column; the PCB is provided with a plurality of welding pads, and the welding pads are welded with the puncture type terminals in the grooves of the coil framework correspondingly.

Further, the device comprises a rotor assembly, the rotor assembly comprises a rotor shaft, a rotor core, a front bearing, a rear bearing and a light barrier, the front bearing and the rear bearing are respectively fixed at two ends of the rotor shaft, a front bearing chamber is arranged at the center of the front end cover, the front bearing is arranged in the front bearing chamber, a rear bearing chamber is arranged at the center of the rear end cover, the rear bearing is arranged in the rear bearing chamber, the rotor core is provided with a plurality of rotor salient poles, an installation shaft hole is arranged at the center of the rotor core, the rotor core is fixed on the rotor shaft with convex ribs on the excircle through the installation shaft hole, the light barrier is provided with a plurality of light blocking parts which are uniformly distributed and correspond to the number of the rotor salient poles on the circumference, the light barrier is axially arranged between the rear bearing and the rotor core, and the center of the light barrier is provided with a flanging hole which is in interference fit connection with the excircle of the rotor shaft, and the relative angle between the rotor salient pole of the rotor core and the light blocking part of the light blocking plate is fixed.

Further, be provided with the fan on the rotor shaft, the fan is located between rotor core and the rear bearing, be provided with a plurality of inlet ports on the diapire of front end housing, be provided with a plurality of louvres that link up on the lateral wall of rear end housing.

Further, radial grids are arranged between the outer ring of the front bearing chamber of the front end cover and the edge shell of the bottom wall of the front end cover, the air inlet holes are formed by gaps among the grids, the outer diameter of each air inlet hole is larger than the outer diameter of the fan, the axial thickness of each grid is larger than that of the bottom wall of the front end cover, and a plurality of rear reinforcing ribs are uniformly arranged on the outer side of the rear bearing chamber of the rear end cover in the circumferential direction.

Furthermore, a front positioning protrusion is arranged on one side end face of the front end cover opening, a threaded hole is formed in the center of the front positioning protrusion, a plurality of rear positioning protrusions are evenly arranged on one side end face of the rear end cover opening in the axial direction, a through screw mounting hole is formed in the center of each rear positioning protrusion, a yoke portion of the stator core is provided with a convex portion mounting hole for inserting the front positioning protrusions and the rear positioning protrusions, the convex portion mounting hole axially penetrates through the stator core and is located on the outer side of the radial direction of the stator salient pole, a screw is arranged in the screw mounting hole of each rear positioning protrusion, the screw sequentially penetrates through the screw mounting hole of each rear positioning protrusion and the convex portion mounting hole of the stator core and is screwed into the threaded hole of each front positioning protrusion, and the rear end cover, the stator core and the front end cover are fixedly connected.

Further, a front reinforcing rib is arranged between the front positioning protrusion and the outer wall of the outer edge of the grating.

Further, the positive edge of the PCB board of controller is provided with motor control end socket and power input end socket, the reverse side of PCB board is provided with position sensor, the edge of PCB board is provided with the groove of stepping down that is used for the screw to pass, the center of PCB board is provided with the hole of stepping down that steps down for the rear bearing when being used for the motor assembly, still be provided with the motor control socket hole that corresponds with motor control end socket on the diapire of rear end cover and the motor power socket hole that corresponds with motor power input end socket.

Further, the controller includes a PCB board and a control circuit disposed on the PCB board, the control circuit including:

the MCU control unit is arranged in an IV area of the PCB;

the MCU control unit controls the power-on or power-off of the windings through the N-phase winding asymmetric half-bridge circuit;

the MCU control unit detects the current of the windings through the N-phase winding current detection circuits, the winding current detection circuits of i-phase windings and i + 2-phase windings in the N-phase windings are the same current detection circuit, wherein i +2 is less than or equal to N, and N is more than or equal to 4 and is an even number;

the rotor position detection circuit is arranged in a V-shaped area of the PCB and is used for detecting the angle position of the rotor assembly and transmitting the angle position to the MCU control unit;

a DC power input port for inputting a DC power for use by a controller;

and the direct current power supply input port transmits direct current to the auxiliary power supply, and the auxiliary power supply supplies power to the MCU control unit.

Further, N phase winding is 4 phase winding, be provided with 8 pads on the PCB board, 8 the pad is respectively pad A +, pad A-, pad B +, pad B-, pad C +, pad C-, pad D +, pad D-, pad A +, pad A-, pad C +, pad C-distributes in I district of PCB board, pad B +, pad B-, pad D +, pad D-distribute in II district of PCB board, be provided with 8 recesses on the coil skeleton, 8 the recess distributes into with 8 two corresponding regions of pad, the recess is located the corresponding pad below on the PCB board respectively.

Further, still include busbar voltage detection circuitry, busbar voltage detection circuitry sets up between DC power supply input port and auxiliary power supply, DC power supply input port auxiliary power supply and busbar voltage detection circuitry all set up in the VI district of PCB board.

Furthermore, the power debugging and downloading port circuit and the motor control end socket are arranged in the area III of the PCB.

The PCB further comprises a coil temperature detection circuit, wherein the coil temperature detection circuit is used for detecting the working temperature of the motor, and a temperature sensor in the coil temperature detection circuit is arranged on the reverse side of the PCB.

Further, the 4-phase winding is respectively an A-phase winding, a B-phase winding, a C-phase winding and a D-phase winding;

the 4-phase winding asymmetric half-bridge circuit comprises an A-phase asymmetric half-bridge circuit and a C-phase asymmetric half-bridge circuit which are used for driving an A-phase winding and a C-phase winding of the motor, and a B-phase asymmetric half-bridge circuit and a D-phase asymmetric half-bridge circuit which are used for driving a B-phase winding and a D-phase winding of the motor, wherein the A-phase asymmetric half-bridge circuit and the C-phase asymmetric half-bridge circuit are arranged in a first area of a PCB (printed circuit board), and the B-phase asymmetric half-bridge circuit and the D-phase asymmetric half-bridge circuit are arranged in a second area of the PCB;

the 4-phase winding current detection circuit comprises an A-phase current detection circuit, a C-phase current detection circuit, a B-phase current detection circuit and a D-phase current detection circuit, wherein the A-phase current detection circuit and the C-phase current detection circuit are used for detecting currents of an A-phase winding and a C-phase winding, the B-phase current detection circuit and the D-phase current detection circuit are used for detecting currents of a B-phase winding and a D-phase winding, the A-phase current detection circuit and the C-phase current detection circuit are arranged in an I area of a PCB, and the B-phase current detection circuit and the D-phase current detection circuit are arranged in a II area of the PCB.

By adopting the technical scheme, the controller is arranged between the rear end cover and the stator assembly, the circumferential movement of the controller is limited by the positioning columns and the positioning holes, the terminal on the framework is welded and fixed with the welding disc on the PCB of the controller, and the PCB supporting structure is matched with the rear end cover and the heat conducting pad to axially support and limit the controller, so that the controller is more firmly installed. The heat dissipation device has the advantages that the heat conduction pad is used for dissipating heat of the power tube on the controller, the heat dissipation air channel consisting of the air inlet hole, the fan and the heat dissipation holes is used for performing auxiliary heat dissipation on the controller and the stator assembly, the heat dissipation effect is better, a heat radiator does not need to be additionally arranged for dissipating heat of power devices on the driving plate, the structure is compact, and the installation space is saved.

Drawings

FIG. 1 is a front view of a switched reluctance motor for a garden tool according to the present invention;

FIG. 2 is a schematic view illustrating an internal structure of a switched reluctance motor for a garden tool according to the present invention;

FIG. 3 is a schematic view of the inside structure of the rear end cap of the present invention;

FIG. 4 is a schematic view of the outer configuration of the rear end cap of the present invention;

FIG. 5 is a schematic view of the inside structure of the front end cap of the present invention;

FIG. 6 is an exploded schematic view of the stator assembly of the present invention;

fig. 7 is a schematic view of a stator core according to the present invention;

FIG. 8 is a schematic structural diagram of a bobbin of the present invention;

FIG. 9 is an enlarged view of a portion of FIG. 8;

FIG. 10 is a schematic view of the structure of the windings and slots of the stator assembly of the present invention;

FIG. 11 is a front view of the rotor assembly of the present invention;

FIG. 12 is a side view of a rotor assembly of the present invention;

FIG. 13 is a top view of the controller of the present invention;

FIG. 14 is a side view of FIG. 13;

FIG. 15 is an electrical layout diagram of the controller of the present invention;

FIG. 16 is a schematic structural diagram of a heat dissipation air duct according to the present invention;

fig. 17 is a functional block diagram of a control circuit of the controller of the present invention.

Detailed Description

In order that the present invention may be more readily and clearly understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings.

As shown in fig. 1 to 16, a switched reluctance motor for a garden tool includes a front end cover 1, a rear end cover 2, a heat conduction pad 5, a stator assembly 3, a controller 4, and a rotor assembly 6. The front end cover 1 is made of a preferred metallic aluminum material and is subjected to die-casting processing, and the rear end cover 2 is made of a preferred metallic aluminum material and is subjected to die-casting processing. The front end cover 1 is provided with a front bearing chamber 11 at the center, and the rear end cover 2 is provided with a rear bearing chamber 22 at the center. A plurality of rear ribs 24 are uniformly arranged on the outer circumference of the rear bearing chamber 22 of the rear end cover 2, and the ribs are used for improving the rigidity of the rear bearing chamber 22 and preventing vibration and noise generated when the motor is heavily loaded.

As shown in fig. 3 and 4, the inner side surface of the rear end cover 2 is provided with a heat conduction pad mounting portion 21, the heat conduction pad 5 is fan-shaped and mounted in the heat conduction pad mounting portion 21 of the rear end cover 2, and the heat conduction pad 5 is located between the rear end cover 2 and the controller 4. The heat conducting pad mounting part 21 is a fan-shaped sinking groove matched with the shape of the heat conducting pad 5, and the depth of the groove is 0.5-2 mm.

As shown in fig. 6 to 10, the stator assembly 3 includes a stator core 31 and a coil bobbin 32 installed in the stator core 31, the front end cover 1 and the rear end cover 2 are respectively fixed at two ends of the stator core 31, the coil bobbin 32 is further provided with a plurality of positioning posts 321 and a PCB support structure, a plurality of grooves 33 are formed in a radial outer edge of one axial end of the coil bobbin 32, and piercing terminals 35 for electrically connecting with windings 34 on the coil bobbin 32 are inserted into the grooves 33.

The stator core 31 includes a plurality of stator salient poles 311 and stator core slots 312, a plurality of coil formers 322 are disposed in the coil frame 32, the coil formers 322 are wrapped on the stator salient poles 311, the windings 34 are wound on the coil formers 322, and each of the piercing terminals 35 is electrically connected to a terminal of the corresponding winding 34.

As shown in fig. 13 to 15, the controller 4 includes a PCB 41, a power tube 42 mounted on a front surface of the PCB 41, and a position sensor 47 mounted on a rear surface of the PCB 41. The position sensor 47 adopts a photoelectric switch, the position sensor 47 is directly installed on the controller 4, the position sensor 47 is not connected with the controller 4 by a lead, and the position signal transmission is reliable, the anti-interference performance is good, and the cost is low.

The PCB 41 is provided with positioning holes 43 correspondingly assembled with the positioning posts 321 on the coil bobbin 32, the PCB 41 is mounted on the positioning posts 321 through the positioning holes 43 and axially supported by a PCB support structure, the PCB support structure is a plurality of support columns 323 arranged on the coil bobbin 32, the support columns 323 are located below the positioning posts 321, and in addition, the support columns 323 can also be arranged on the coil bobbin 32 without the positioning posts 321. When the PCB 41 is mounted on the bobbin 32, the PCB 41 is mounted on the positioning posts 321 through the positioning holes 43 to ensure that the PCB 41 does not rotate in the circumferential direction. The support column 323 and the rear end cover 2 press the controller 4 through the heat conduction pad 5 to limit the axial movement of the controller 4, so that the controller 4 is reliably connected.

The PCB 41 is provided with a plurality of pads 44, the pads 44 are correspondingly soldered to the piercing terminals 35 in the grooves 33 of the bobbin 32, and the piercing terminals 35 on the bobbin 32 are soldered to the pads 44 on the PCB. The terminal of the winding 34 of the motor is directly welded and electrically connected with the welding pad 44 on the PCB 41 of the controller 4 through the puncture-type terminal 35, no wire is needed for connection, and the interference signal generated to the outside is small and the cost is low.

As shown in fig. 1 and 2, the heat conduction pad 5 is mounted between the rear end cover 2 and the controller 4, one surface of the heat conduction pad 5 is in close contact with the inner side surface of the rear end cover 2, and the other surface of the heat conduction pad 5 is in close contact with the power tube 42 of the controller 4. For reliable bonding, the distance from the heat conducting pad mounting part 21 of the rear end cover 2 to the heat radiating surface of the power tube 42 is smaller than the free thickness of the heat conducting pad 5 by 0.5-1 mm, and the heat conducting pad 5 can be fully bonded with the rear end cover 2 and the power tube 42 by compressing the heat conducting pad 5, so that the heat radiating effect is ensured to the maximum extent. The thermal pad 5 is an insulating and thermally conductive material having elasticity, viscosity and compressibility, and preferably a material in which silicon rubber is used as a base material and boron nitride and alumina are used as fillers.

When the motor runs, the heat generated by the power tube 42 is transferred to the rear end cover 2 through the heat conducting pad 5, and a radiator is not required to be additionally arranged on the surface of the power tube 42. The motor has the advantages of compact structure and low cost. The arrangement of the heat conducting pad 5 can also increase the creepage distance from the pin of the power tube 42 to the end cover, and avoid electric shock accidents caused by the too close distance between the high-voltage pin of the power tube 42 and the end cover.

As shown in fig. 11 and 12, the rotor assembly 6 includes a rotor shaft 61, a rotor core 62, a front bearing 63, a rear bearing 64 and a light barrier 65, the rotor core 62 has a plurality of rotor salient poles 621, a mounting shaft hole is provided at the center of the rotor core 62, the rotor core 62 is fixed on the rotor shaft 61 with a convex rib at the outer circle through the mounting shaft hole, the front bearing 63 and the rear bearing 64 are respectively fixed at both ends of the rotor shaft 61, the front bearing 63 is disposed in the front bearing chamber 11, and the rear bearing 64 is disposed in the rear bearing chamber 22.

The light barrier 65 is provided with a plurality of light blocking portions 651 which are uniformly distributed and correspond to the rotor salient poles 621 in number on the circumference of the light barrier 65, the light barrier 65 is axially installed between the rear bearing 64 and the rotor core 62, the light barrier 65 is made of a metal plate material through stamping, the center of the light barrier 65 is provided with a flanging hole 652 which is in interference fit connection with the excircle of the rotor shaft 61, the relative angle between the rotor salient poles 621 of the rotor core 62 and the light blocking portions 651 of the light barrier 65 is fixed, and when the rotor core 62 and the light barrier 65 are assembled, the relative position between the rotor core 62 and the light barrier 65 is guaranteed to be fixed through an auxiliary positioning tool. Two position sensors 47 installed on the opposite side of the PCB 41 determine the angular position of the rotor assembly 6 by detecting the rotor assembly 6 installed with the light barrier 65, and when the rotor assembly 6 rotates to a preset position, a control circuit on the controller 4 controls the power tube 42 to be turned on or off, so that the coil windings 34 on the corresponding stator assembly 3 are powered on or off, and the rotor assembly 6 continuously rotates under the electromagnetic force of the coils.

In order to solve the problem of heat dissipation between the coil windings of the stator assembly 3 and the power tube 42 of the controller 4, the fan 66 is disposed on the rotor shaft 61, the fan 66 is located between the rotor core 62 and the rear bearing 64, and the side wall of the rear end cap 2 is provided with a plurality of through heat dissipation holes 23. As shown in fig. 5, a plurality of air inlet holes are formed in the bottom wall of the front end cover 1, radial grids 12 are arranged between the outer ring of the front bearing chamber 11 of the front end cover 1 and the edge casing of the bottom wall of the front end cover 1, the air inlet holes are formed by gaps among the grids 12, the outer diameter of each air inlet hole is larger than that of the fan 66, and the axial thickness of each grid 12 is larger than that of the bottom wall of the front end cover 1, so that the strength of the front bearing chamber 11 is enhanced.

When the motor rotates, the fan 66 rotates along with the rotor shaft 61, air near the front end cover 1 flows into the air inlet, and the air flowing into the air inlet passes through the coil winding 34 on the stator assembly 3 under the action of the fan 66 and flows out of the heat radiation holes 23 of the rear end cover 2. As shown in fig. 16, the heat dissipation air duct composed of the air intake holes, the fan 66 and the heat dissipation holes 23 can cool the coil windings 34 on the stator assembly 3 and the power tubes 42 on the controller 4 at the same time. Compared with a system with a motor body and a drive plate separated, the motor with the integrated structure does not need to consider the scheme of designing the heat dissipation structures of the motor coil and the power device on the drive plate respectively.

As shown in fig. 1 to 9, a front positioning protrusion 13 is provided on an end surface of one side of the opening of the front end cover 1, and a threaded hole 131 is provided in the center of the front positioning protrusion 13. A plurality of rear positioning projections 25 are uniformly arranged on the end face of one side of the opening of the rear end cover 2 in the axial direction, the length of the rear positioning projections 25 extending from the end face in the axial direction is 3-5mm, and a through screw mounting hole 251 is arranged in the center of each rear positioning projection 25. The yoke part of the stator core 31 is provided with a convex part mounting hole 313 for inserting the front positioning projection 13 and the rear positioning projection 25, the front positioning projection 13 and the rear positioning projection 25 are identical in structure and shape, and the front and rear positioning projections are in clearance fit with the convex part mounting hole 313. The convex mounting hole 313 axially penetrates through the stator core 31 and is positioned on the outer side of the radial direction of the stator salient pole 311, a screw 7 is arranged in the screw mounting hole 251 of the rear positioning projection 25, the screw 7 sequentially penetrates through the screw mounting hole 251 of the rear positioning projection 25 and the convex mounting hole 313 of the stator core 31 and is screwed into the threaded hole 131 of the front positioning projection 13, and the rear end cover 2, the stator core 31 and the front end cover 1 are fixedly connected.

The front end cover, the rear end cover and the stator core 31 of the invention do not need to be additionally processed with spigot structures, and the front positioning boss and the rear positioning boss can ensure the coaxiality of the front end cover, the rear end cover and the stator core 31, so that the air gap between the rotor assembly 6 and the stator assembly 3 of the motor is uniform, and the operation is balanced; the invention does not need a motor shell, and the excircle part of the stator core 31, the front end cover 1 and the rear end cover 2 protect the internal parts of the motor rotor assembly 6, the controller 4 and the like.

As shown in fig. 5, a front reinforcing rib 14 is provided between the front positioning protrusion 13 and the outer wall of the outer edge of the grille 12, and the front reinforcing rib 14 can ensure the strength of the bottom wall of the front end cover 1.

As shown in fig. 13 to 15, a motor control end socket 45 and a power input end socket 46 are disposed on an edge of a front side of a PCB 41 of the controller 4, a position sensor 47 is disposed on a back side of the PCB 41, an abdicating slot 411 for a screw 7 to pass through is disposed on an edge of the PCB 41, an abdicating hole 412 for the rear bearing 64 during motor assembly is disposed in a center of the PCB 41, and a motor control socket hole 26 corresponding to the motor control end socket 45 and a motor power socket hole 27 corresponding to the motor power input end socket 46 are further disposed on a bottom wall of the rear end cover 2.

As shown in fig. 13 to 15, in the present embodiment, a 4-phase motor is taken as an example:

the PCB 41 is provided with 8 bonding pads 44, the 8 bonding pads 44 are respectively a bonding pad A +, a bonding pad B +, a bonding pad C +, a bonding pad D +, a bonding pad A +, a bonding pad C + and a bonding pad C-which are distributed in a region I of the PCB 41, the bonding pad B +, the bonding pad B-, the bonding pad D + and the bonding pad D-which are distributed in a region II of the PCB 41, the coil framework 32 is provided with 8 grooves 33, the 8 grooves 33 are distributed into two regions corresponding to the 8 bonding pads 44, and the grooves 33 are respectively positioned below the corresponding bonding pads 44 on the PCB 41.

The number of the coils of the stator component is 8, and the coils are respectively wound and installed on a coil rack 322 wrapping the stator salient pole 311, wherein each 2 coils are connected in series or in parallel to form a phase winding 34, and the 4-phase windings are respectively an A-phase winding 341, a B-phase winding 342, a C-phase winding 343 and a D-phase winding 344; each phase winding 34 has two terminals, respectively: the terminal A + and the terminal A belonging to the A-phase winding, the terminal B + and the terminal B belonging to the B-phase winding, the terminal C + and the terminal C belonging to the C-phase winding, and the terminal D + and the terminal D belonging to the D-phase winding. The terminals of each winding 34 are electrically connected to corresponding piercing terminals 35 located in the grooves 33.

As shown in fig. 17, the control circuit of the controller 4 includes an MCU control unit, an N-phase winding asymmetric half-bridge circuit, an N-phase winding current detection circuit, a rotor position detection circuit, a dc power input port, an auxiliary power supply, a bus voltage detection circuit, a power supply debug and download port circuit, and a coil temperature detection circuit.

The MCU control unit is arranged in the IV area of the PCB 41.

And the MCU control unit controls the power-on or power-off of the winding through the N-phase winding asymmetric half-bridge circuit.

The MCU control unit detects the current of the winding through an N-phase winding current detection circuit, wherein the winding current detection circuits of i-phase windings and i + 2-phase windings in the N-phase windings are the same current detection circuit, i +2 is less than or equal to N, N is more than or equal to 4 and is an even number, and N is 4 in the embodiment; the angular position of the rotor assembly 6, as detected by the rotor position detection circuit, is communicated to the MUC control unit, which controls the energisation or de-energisation of the windings 34 by means of the N-phase winding asymmetric half-bridge circuit. Because the i phase and the i +2 phase windings are not electrified simultaneously, in the design of the N-phase winding asymmetric half-bridge circuit, the i phase and the i +2 phase share one current detection circuit, the number of the current detection circuits can be reduced by half, and the use of parts is reduced. Correspondingly, when the circuit is designed on the PCB 41, the i-phase and i + 2-phase half-bridge circuits and the shared current detection circuit are arranged in one region, the wiring between the components is shortest, the path is optimal, and the overall layout is better.

The rotor position detection circuit is used to detect the angular position of the rotor assembly 6, and as shown in fig. 15, the rotor position detection circuit is disposed in the v region of the PCB 41 and transmitted to the MCU control unit.

The dc power input port is used to input dc power for the controller 4.

The direct current power supply input port transmits direct current to the auxiliary power supply, and the auxiliary power supply supplies power to the MCU control unit.

The bus voltage detection circuit is provided between the dc power input port and the auxiliary power supply, and both the dc power input port auxiliary power supply and the bus voltage detection circuit are provided in the vi region of the PCB 41 as shown in fig. 15.

As shown in fig. 15, the power debug and download port circuit and the motor control terminal socket 45 are both disposed in the region iii of the PCB 41.

The coil temperature detecting circuit is used to detect the operating temperature of the motor, and as shown in fig. 14, a temperature sensor 48 in the coil temperature detecting circuit is provided on the reverse side of the PCB board 41. In order to prevent the motor from being burnt out due to too high temperature rise when the motor is in overload operation, the PCB 41 is also provided with a coil temperature detection circuit for detecting the temperature of the coil winding 34 of the stator component 3, and when the coil temperature detection circuit detects that the temperature of the coil winding 34 of the stator component 3 nearby exceeds a specified value, the MCU control unit controls the N-phase winding asymmetric half-bridge circuit to enable the motor to reduce power to operate or stop operating, the temperature of the motor does not rise any more, and the motor operates in a safe working temperature range.

The 4-phase winding asymmetric half-bridge circuit comprises an A-phase asymmetric half-bridge circuit and a C-phase asymmetric half-bridge circuit for driving an A-phase winding and a C-phase winding of the motor, and a B-phase asymmetric half-bridge circuit and a D-phase asymmetric half-bridge circuit for driving a B-phase winding and a D-phase winding of the motor, as shown in fig. 15, the A-phase asymmetric half-bridge circuit and the C-phase asymmetric half-bridge circuit are arranged in a region I of a PCB (printed circuit board) 41, and the B-phase asymmetric half-bridge circuit and the D-phase asymmetric half-bridge circuit are arranged in a region II of the PCB 41;

the 4-phase winding current detection circuit includes an a-phase current detection circuit and a C-phase current detection circuit for detecting a-phase winding current and a C-phase current detection circuit for detecting a B-phase winding current and a D-phase current detection circuit for detecting a D-phase winding current, as shown in fig. 15, the a-phase current detection circuit and the C-phase current detection circuit are disposed in a region i of the PCB 41, and the B-phase current detection circuit and the D-phase current detection circuit are disposed in a region ii of the PCB 41.

The technical problems, technical solutions and advantages of the present invention have been described in detail with reference to the above embodiments, and it should be understood that the above embodiments are merely exemplary and not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A switched reluctance motor for a garden tool, comprising:

a front end cap (1);

the heat conduction pad comprises a rear end cover (2), wherein a heat conduction pad mounting part (21) is arranged on the inner side surface of the rear end cover (2);

the stator assembly (3), the stator assembly (3) includes a stator core (31) and a coil frame (32) installed in the stator core (31), and the front end cover (1) and the rear end cover (2) are respectively fixed at two ends of the stator core (31);

the controller (4), the controller (4) is arranged between the stator assembly (3) and the rear end cover (2);

the heat conduction pad (5), the heat conduction pad (5) sets up in heat conduction pad installation department (21) of rear end cap (2), heat conduction pad (5) are located between rear end cap (2) and controller (4).

2. The switched reluctance motor for a garden tool according to claim 1, wherein: the shape of heat conduction pad (5) is fan-shaped, heat conduction pad installation department (21) are with the fan-shaped heavy groove of heat conduction pad (5) shape adaptation, controller (4) include PCB board (41), install power tube (42) openly at PCB board (41), the one side of heat conduction pad (5) is hugged closely with the fan-shaped heavy groove of heat conduction pad installation department (21) of rear end cap (2), the another side and the power tube (42) of heat conduction pad (5) are hugged closely, the fan-shaped heavy tank bottom surface of heat conduction pad installation department (21) of rear end cap (2) is less than the free thickness size of heat conduction pad (5) 0.5mm ~ 1mm to the distance of the cooling surface of power tube (42).

3. The switched reluctance motor for a garden tool according to claim 1, wherein: stator core (31) include a plurality of stator salient poles (311) and stator core groove (312), be provided with a plurality of coil formers (322) in coil skeleton (32), coil former (322) parcel is on stator salient pole (311), the coiling has winding (34) on coil former (322), the radial outward flange of axial one end of coil skeleton (32) is provided with a plurality of recesses (33), it has puncture formula terminal (35) that are used for with winding (34) electric connection on coil skeleton (32) to peg graft in recess (33), every puncture formula terminal (35) respectively with the wiring end electric connection of the winding (34) that corresponds.

4. The switched reluctance motor for a garden tool according to claim 3, wherein: the coil framework (32) is also provided with a plurality of positioning columns (321) and a PCB supporting structure, the PCB supporting structure is a plurality of supporting columns (323) arranged on the coil framework (32), and the supporting columns (323) are positioned below the positioning columns (321); the PCB (41) is provided with a positioning hole (43) correspondingly assembled with the positioning column (321) on the coil framework (32), the PCB (41) is mounted on the positioning column (321) through the positioning hole (43) and is axially supported by the supporting column (323); the PCB (41) is provided with a plurality of bonding pads (44), and the bonding pads (44) are welded with the piercing terminals (35) in the grooves (33) of the coil frame (32) correspondingly.

5. The switched reluctance motor for a garden tool according to claim 1, wherein: comprises a rotor assembly (6), the rotor assembly (6) comprises a rotor shaft (61), a rotor core (62), a front bearing (63), a rear bearing (64) and a light barrier (65), the front bearing (63) and the rear bearing (64) are respectively fixed at two ends of the rotor shaft (61), a front bearing chamber (11) is arranged at the center of the front end cover (1), the front bearing (63) is arranged in the front bearing chamber (11), a rear bearing chamber (22) is arranged at the center of the rear end cover (2), the rear bearing (64) is arranged in the rear bearing chamber (22), the rotor core (62) is provided with a plurality of rotor salient poles (621), an installation shaft hole is arranged at the center of the rotor core (62), the rotor core (62) is fixed on the rotor shaft (61) with convex ribs on the excircle through the installation shaft hole, the light barrier (65) is provided with a plurality of light barriers (651) which are uniformly distributed and correspond to the number of the rotor salient poles (621) on the circumference, the light barrier (65) is axially installed between the rear bearing (64) and the rotor core (62), a flanging hole (652) in interference fit connection with the excircle of the rotor shaft (61) is formed in the center of the light barrier (65), and the relative angle between a rotor salient pole (621) of the rotor core (62) and a light blocking part (651) of the light barrier (65) is fixed.

6. The switched reluctance motor for a garden tool according to claim 5, wherein: be provided with fan (66) on rotor shaft (61), fan (66) are located between rotor core (62) and rear bearing (64), be provided with a plurality of inlet ports on the diapire of front end housing (1), be provided with a plurality of louvres (23) that link up on the lateral wall of rear end housing (2).

7. The switched reluctance motor for a garden tool according to claim 6, wherein: radial grids (12) are arranged between the outer ring of a front bearing chamber (11) of the front end cover (1) and an edge shell of the bottom wall of the front end cover (1), air inlet holes are formed by gaps among the grids (12), the outer diameter of each air inlet hole is larger than that of a fan (66), the axial thickness of each grid (12) is larger than that of the bottom wall of the front end cover (1), and a plurality of rear reinforcing ribs (24) are uniformly arranged on the outer side of a rear bearing chamber (22) of the rear end cover (2) in the circumferential direction.

8. The switched reluctance motor for a garden tool according to claim 7, wherein: a front positioning projection (13) is arranged on one side end face of an opening of the front end cover (1), a threaded hole (131) is formed in the center of the front positioning projection (13), a plurality of rear positioning projections (25) are uniformly arranged on one side end face of an opening of the rear end cover (2) in the axial direction, a through screw mounting hole (251) is formed in the center of each rear positioning projection (25), a yoke portion of each stator core (31) is provided with a projection mounting hole (313) used for inserting the front positioning projection (13) and the rear positioning projections (25), the projection mounting hole (313) axially penetrates through the stator core (31) and is positioned on the outer side of the radial direction of each stator salient pole (311), a screw (7) is arranged in the screw mounting hole (251) of each rear positioning projection (25), and the screw (7) sequentially penetrates through the screw mounting hole (251) of each rear positioning projection (25) and the projection mounting hole (313) of each stator core (31) and is screwed into the threaded hole (131) of the front positioning projection (13), and fixedly connecting the rear end cover (2), the stator core (31) and the front end cover (1).

9. The switched reluctance motor for a garden tool according to claim 8, wherein: a front reinforcing rib (14) is arranged between the front positioning protrusion (13) and the outer wall of the outer edge of the grating (12).

10. The switched reluctance motor for a garden tool according to claim 8, wherein: the positive edge of PCB board (41) of controller (4) is provided with motor control end socket (45) and power input end socket (46), the edge of PCB board (41) is provided with the groove of stepping down (411) that is used for screw (7) to pass, the center of PCB board (41) is provided with hole of stepping down (412) that gives back bearing (64) to step down when being used for the motor assembly, still be provided with motor control socket hole (26) that correspond with motor control end socket (45) and motor power socket hole (27) that correspond with motor power input end socket (46) on the diapire of rear end housing (2).

11. A switched reluctance motor for a garden tool, according to claim 1, characterized in that the controller (4) comprises a PCB board (41) and a control circuit arranged on the PCB board (41), the control circuit comprising:

an MCU control unit;

and the rotor position detection circuit is used for detecting the angle position of the rotor assembly (6) and transmitting the angle position to the MCU control unit.

12. The switched reluctance motor for a garden tool according to claim 11, wherein: the N-phase winding (34) is a 4-phase winding, 8 bonding pads (44) are arranged on the PCB (41), and the 8 bonding pads (44) are respectively bonding pads (A +), bonding pads (A-), bonding pads (B +), bonding pads (B-), bonding pads (C +), bonding pads (C-), bonding pads (D +), and bonding pads (D-), the bonding pad (A +), the bonding pad (A-), the bonding pad (C +), and the bonding pad (C-) are distributed in the I area of the PCB (41), the bonding pad (B +), the bonding pad (B-), the bonding pad (D +), and the bonding pad (D-) are distributed in a region II of the PCB (41), the coil framework (32) is provided with 8 grooves (33), the 8 grooves (33) are distributed into two areas corresponding to the 8 bonding pads (44), the grooves (33) are respectively positioned below corresponding pads (44) on the PCB (41).

13. The switched reluctance motor for a garden tool according to claim 12, wherein: the 4-phase windings are respectively an A-phase winding (341), a B-phase winding (342), a C-phase winding (343) and a D-phase winding (344);

the 4-phase winding asymmetric half-bridge circuit comprises an A-phase asymmetric half-bridge circuit and a C-phase asymmetric half-bridge circuit which are used for driving an A-phase winding and a C-phase winding of a motor, and a B-phase asymmetric half-bridge circuit and a D-phase asymmetric half-bridge circuit which are used for driving a B-phase winding and a D-phase winding of the motor, wherein the A-phase asymmetric half-bridge circuit and the C-phase asymmetric half-bridge circuit are arranged in a region I of a PCB (41), and the B-phase asymmetric half-bridge circuit and the D-phase asymmetric half-bridge circuit are arranged in a region II of the PCB (41);

the 4-phase winding current detection circuit comprises an A-phase current detection circuit, a C-phase current detection circuit, a B-phase current detection circuit and a D-phase current detection circuit, wherein the A-phase current detection circuit and the C-phase current detection circuit are used for detecting currents of an A-phase winding and a C-phase winding, the B-phase current detection circuit and the D-phase current detection circuit are used for detecting currents of a B-phase winding and a D-phase winding, the A-phase current detection circuit and the C-phase current detection circuit are arranged in an I area of a PCB (41), and the B-phase current detection circuit and the D-phase current detection circuit are arranged in a II area of the PCB (41).