CN110635623A - Switched reluctance motor with heat dissipation structure and electric garden tool including the motor - Google Patents

Abstract

A switched reluctance motor with a heat dissipation structure and an electric garden tool including the motor. The switched reluctance motor includes: a housing having opposing first and second ends and a tubular wall extending between the first and second ends; an air inlet member disposed adjacent the first end and has an air inlet; an air outlet component is arranged near the second end and has an air outlet; the switched reluctance motor body is arranged in the casing and has an output shaft extending along the first direction, a rotor and a stator arranged around the output shaft The controller part is arranged in the casing and is located between the air inlet part and the switched reluctance motor body in the first direction; and the air draft part is arranged on the output shaft and is located on the side of the switched reluctance motor body away from the controller part One side; wherein at least one air duct is formed between the shell, the controller part and the switched reluctance motor body to dissipate heat from the controller part and the switched reluctance motor body.

Description

Switched reluctance motor with heat dissipation structure and electric garden tool including the motor

technical field

The invention relates to a switched reluctance motor with a heat dissipation structure and an electric garden tool including the switched reluctance motor.

Background technique

Motors are widely used in households, gardens, environmental maintenance and other fields. At present, most manufacturers of power tools and garden tools use series-excited motors to drive mechanical structures to rotate. As we all know, series motors use carbon brushes and commutators, so they have short lifespan, high failure rate, and carbon brush dust will pollute the environment. There are also some manufacturers who use permanent magnet brushless DC motors to drive the mechanical structure to rotate, but permanent magnet brushless DC motors need to use permanent magnet materials, so they are expensive, easy to demagnetize during overload operation, and easy to absorb iron dust and cause Motor failure.

The use of switched reluctance motors overcomes the above problems well, but the use of switched reluctance motors will bring some other problems.

First of all, in the switched reluctance motor, the power rectifier module and the motor drive module are designed on an integrated board-type controller assembly, which is too large to make the external air flow difficult to circulate, which affects heat dissipation, and also affects the convenience of the whole machine; in addition , It is necessary to separate the independent heat dissipation of the controller component and the motor body, which increases the corresponding cost.

Secondly, when the integrated centralized heat dissipation scheme is adopted, the placement position of the controller component deviates from the optimal heat dissipation air path of the reluctance motor, and the heat of the controller component itself is not easy to dissipate, and when the controller component uses components with insufficient temperature resistance, The controller components are easy to burn out, which eventually leads to the failure of the motor, and the cost of selecting components with higher temperature resistance is too high.

Furthermore, the unreasonable design of the size of the air inlet and outlet of the heat dissipation air duct in the switched reluctance motor leads to failure to achieve the best heat dissipation effect.

Furthermore, due to the high power density of the switched reluctance motor, the motor generates a lot of heat. At this time, it is necessary to use cooling fan blades to increase heat dissipation, such as centrifugal or axial flow fan blades. The fan blades will consume part of the power of the motor itself. As a result, the output power of the motor decreases, and the power density of the motor decreases. The mismatch between the fan blade size and the motor power caused some problems. If the size of the designed fan blade is too large, it will occupy the space of the motor, especially the axial height dimension, which will affect the convenience of the whole machine (such as garden tools and electric tools), and at the same time excessively consume the power of the motor itself. If the size of the fan blade is too small, the heat dissipation effect of the motor will not be obvious.

Contents of the invention

Therefore, the object of the present invention is to provide a switched reluctance motor with a heat dissipation structure and an electric garden tool including the switched reluctance motor, which can perform integrated and centralized heat dissipation on the motor and controller components, so the volume is small and the heat dissipation efficiency is high. High, low cost and long life.

The present invention relates to a switched reluctance motor with a heat dissipation structure, the switched reluctance motor comprising: a housing having opposite first and second ends and a housing extending between the first and second ends The tubular wall; the air inlet part is arranged near the first end and has an air inlet; the air outlet part is arranged near the second end and has an air outlet; the switched reluctance motor body is arranged in the shell and has an air outlet along the first The output shaft extending in the direction, the rotor and the stator arranged around the output shaft; the controller part is arranged in the shell and is located between the air inlet part and the switched reluctance motor body in the first direction; and the ventilation part is arranged on the output shaft and located on the side of the switched reluctance motor body away from the controller part; wherein at least one air duct is formed between the shell, the controller part and the switched reluctance motor body, so as to control the controller part and the switched reluctance motor body Heat dissipation.

In one embodiment, the controller component includes: a bracket fixed in the casing; and a motor drive board and a power rectifying board arranged side by side on the bracket in a second direction perpendicular to the first direction.

In one embodiment, the at least one air passage includes a first air passage formed between the housing, the controller component and the stator, and a second air passage formed between the stator and the rotor.

In one embodiment, the switched reluctance motor body further includes a first end cover and a second end cover located at both ends of the rotor and the stator, and the first end cover and the second end cover are hollowed out.

In one embodiment, the bracket of the controller component is disposed on the first end cover, and the bracket is a rectangular frame and the plane where it is located is parallel to the first direction.

In one embodiment, the switched reluctance motor further includes a mounting plate, on which the second end of the casing is disposed and the output shaft of the switched reluctance motor body passes through a hole in the mounting plate.

In one embodiment, the air outlet component is integrally formed with the mounting plate as a single component.

In one embodiment, the outlet element is arranged on the tubular wall of the housing.

In one embodiment, the housing has a plurality of protrusions protruding inwardly from and extending along portions of the tubular wall thereof for securing the switched reluctance motor body within the housing.

In one embodiment, the plurality of protrusions are evenly distributed around the circumference of the tubular wall.

In one embodiment, said tubular wall forms a non-zero angle with the first direction.

In one embodiment, said angle is in the range of 2° to 5°.

In one embodiment, said angle is in the range of 3° to 4.5°.

In one embodiment, the housing comprises a cavity at the second end for receiving a draft element.

In one embodiment, the draft component includes a plurality of vanes.

In one embodiment, the height of the blades in the first direction is in the range of 4.5 mm to 7 mm.

In one embodiment, the distance along the first direction between the air inlet part and the controller part is in the range of 5 mm to 20 mm.

In one embodiment, said distance is in the range of 8mm to 12mm.

In one embodiment, the ratio of the air inlet area to the air outlet area of the casing is between 1:3 and 1:1.5.

In one embodiment, the ratio of the air inlet area to the air outlet area of the casing is between 1:2.5 and 1:2.

The invention also relates to an electric garden tool comprising a switched reluctance motor as described above.

Description of drawings

The advantages and objects of the present invention can be better understood from the following preferred embodiments of the present invention described in detail with reference to the accompanying drawings. In order to better show the relationship of components in the drawings, the drawings are not drawn to scale. In the attached picture:

Fig. 1 shows the three-dimensional appearance view of the switched reluctance motor with heat dissipation structure of the present invention;

Fig. 2 is a partial sectional view of the switched reluctance motor of Fig. 1;

Fig. 3 shows the schematic diagram of the casing of the switched reluctance motor with heat dissipation structure of the present invention;

Fig. 4a and Fig. 4b show the structural exploded diagrams of different directions of the switched reluctance motor with heat dissipation structure of the present invention;

Fig. 5 shows a schematic diagram of a switched reluctance motor body according to an embodiment of the present invention;

Fig. 6 shows a schematic diagram of the first end cover and the second end cover of the switched reluctance motor body of Fig. 5;

Fig. 7 shows a schematic cross-sectional view of the stator and the rotor of the switched reluctance motor body of Fig. 5;

Figure 8 shows a schematic diagram of a controller component of an embodiment of the present invention;

Fig. 9 shows a schematic diagram of the flow path of the air flow in the switched reluctance motor with heat dissipation structure of the present invention;

Fig. 10 is a schematic diagram showing the dimensions of various components in one embodiment of the present invention;

Fig. 11 is a schematic diagram showing the size of the blades of the air draft component in Fig. 10;

Fig. 12 shows a schematic diagram of a casing of a switched reluctance motor according to another embodiment of the present invention; and

Fig. 13a and Fig. 13b show the exploded schematic diagrams of the structure of the electric garden tool in different directions according to an embodiment of the present invention.

Detailed ways

Various embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Here, it is to be noted that, in the drawings, the same reference numerals are assigned to components having substantially the same or similar structures and functions, and repeated descriptions about them will be omitted. If not specifically stated, the terms "first direction", "second direction", "rotational direction" and the like herein are all described relative to the drawings of the present invention. The description of "first" and its variants is only for distinguishing each component, and does not limit the scope of the present invention. Without departing from the scope of the present invention, "first component" can be written as "second component", etc. .

The accompanying drawings in this specification are schematic diagrams, which assist in explaining the concept of the present invention, and schematically represent the shapes of various parts and their interrelationships.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to FIGS. 1 to 11 .

Referring to Figures 1 to 4a and 4b, a switched reluctance motor 100 with a heat dissipation structure according to an embodiment of the present invention includes a housing 1, an air inlet part 2, an air outlet part 3, a switched reluctance motor body 4, and a controller part 5 and the ventilation part 6.

The housing 1 has a tubular wall 11 , preferably at an angle to a first direction, and opposite first and second ends 12 , 13 . In the diagram on the left side of FIG. 1 , the first direction is a vertical upward direction. In FIG. 2 and the right view of FIG. 3 , the first direction is a vertical downward direction. That is to say, the shell expands gradually along the first direction and is trumpet-shaped. As shown in Figure 3, the angle α formed by the tubular wall of the housing with the first direction is in the range of 2° to 5°, preferably in the range of 3° to 4.5°. The cross-sectional shape of the tubular wall is preferably circular, but it can also be in other shapes, such as rectangular, polygonal, etc. For example, the housing can also be pyramid-shaped.

The air inlet component 2 is disposed near the first end and has an air inlet 21 . As shown in FIG. 1 and FIG. 3 , the air inlet 21 is a plurality of arc-shaped air outlets with the center of the air inlet part 2 as the center. The air intake is not only used to allow air flow into the housing, but also to filter debris to protect the switched reluctance motor. The air inlets 21 can also be regularly arranged rectangular air outlets. As shown in the figure, the air inlet part 2 is integrally formed with the casing as a single part, that is to say, the air inlet is arranged on the end wall at the first end of the casing. However, the air inlet component in other embodiments of the present invention can also be a component separate from the housing, which can be connected to the first end of the housing by screws or in a buckle manner.

The air outlet component 3 is disposed close to the second end of the housing and has an air outlet 31 . As shown in FIG. 2 and FIG. 3 , the air outlet component 3 and the housing are integrally formed as a single component, that is to say, the air outlet 31 is arranged on the tubular wall of the housing and is located at the second end. When the air outlet component is arranged on the tubular wall, the centrifugal air blade side air outlet mode is adopted. The uniform distribution of the air outlets minimizes resistance to air flow.

The switched reluctance motor body 4 is used to provide power for the mechanical structure, is disposed in the casing and has an output shaft 41 extending along a first direction. As shown in FIGS. 5 and 7 , the switched reluctance motor body 4 further includes a rotor 42 and a stator 43 arranged around the output shaft 41 . As shown in FIG. 3 , the casing has a plurality of protrusions 14 (such as ribs) protruding inwardly from the tubular wall and extending along part of the tubular wall, for fixing the switched reluctance motor body in the casing. A plurality of protrusions 14 are evenly distributed in the circumferential direction of the tubular wall. In other embodiments of the present invention, according to the shape and installation requirements of the switched reluctance motor body, the plurality of protrusions 14 may also be unevenly distributed in the circumferential direction of the tubular wall. The number of protrusions 14 is, for example, 3-6.

The controller component is used to provide control signals to the switched reluctance motor, so that the motor can work normally under rated working conditions. The controller part 5 is arranged in the housing and located between the air inlet part 2 and the switched reluctance motor body 4 in the first direction. For example, the controller component may be secured to the inside of the tubular wall of the housing.

The exhaust component is used to enhance heat dissipation and accelerate the circulation of air flow in the heat dissipation air duct. The ventilation part 6 is arranged on the output shaft and located on the side of the switched reluctance motor body 4 away from the controller part 5 . For example, the housing also comprises, at the second end, a cavity 15 for receiving a draft element, as shown in FIG. 3 . For example, as shown in FIGS. 4 a and 4 b , the draft component includes fan blades 16 . The blades are mounted on the output shaft through bushes 17, for example, as shown in the left diagram of FIG. 11 . In addition, in order to achieve a noise reduction effect, the number of fan blades may be an odd number. When the fan blade rotates at a high speed, a negative pressure zone is formed in the cavity containing it, so that the air flow is quickly sucked into the cavity, and finally flows out from the air outlet.

In addition, as shown in Fig. 2 and Fig. 4a, 4b, the switched reluctance motor also includes a mounting plate 7, the second end of the casing 1 is arranged on the mounting plate and the output shaft 41 of the switched reluctance motor body 4 passes through the mounting plate in the hole. The switched reluctance motor can be installed on an electric tool such as an electric garden tool through a mounting plate to drive the mechanical structure of the electric tool to work.

In one embodiment of the present invention, the air outlet component 3 and the mounting plate 7 are integrally formed as a single component, that is, the air outlet is arranged on the mounting plate 7. At this time, for example, the vertical air outlet mode of axial flow blades is adopted, and the air outlet The direction is consistent with the direction of the wind.

When the air outlet component is arranged on the tubular wall, the air outlet is arranged at the same height as the fan blade. When the air outlet component is arranged on the mounting plate, the air outlet can be set to be concentric with the fan blade.

As shown in FIG. 2 , the centerline of the controller component (as shown by the dot-dash line in the figure) basically coincides with the centerline of the switched reluctance motor body (ie, the centerline of the output shaft). As shown in FIG. 2 , at least one air duct is formed between the casing, the controller part and the switched reluctance motor body to dissipate heat from the controller part and the switched reluctance motor body. When the ventilation part 6 is in operation, the air flow enters the casing from the air inlet, first flows through the controller part 5 and quickly takes away the heat generated by the controller part, and then flows through the switched reluctance motor body and takes away the heat generated by the motor. Go, and finally flow out from the exit.

The controller part is closer to the air inlet, and can be in contact with the air flow for the first time. Being close to the air inlet allows the controller components to be given priority to heat dissipation, and the structure of the controller components can be designed to be more compact and smaller.

Referring to FIG. 4 a , FIG. 4 b and FIG. 8 , the controller component 5 includes a bracket 51 , a motor driving board 52 and a power rectifying board 53 . The bracket 51 is fixed in the casing, and is, for example, a substantially rectangular frame. The plane of the rectangular frame is substantially parallel to the output shaft, so the resistance to the air flowing through the controller components is minimal. The motor driving board 52 and the power rectifying board 53 are arranged side by side on the support in a second direction perpendicular to the first direction (the direction in which the output shaft 41 is located). In one example of the invention, the bracket may be secured to the inside of the tubular wall of the housing.

As shown in the diagram on the right side of FIG. 8 , in the second horizontal direction to the right, the power rectifying board 53 and the motor driving board 52 are installed on both sides of the bracket respectively. The first direction in FIG. 8 is a vertical downward direction, the second direction in the left diagram is a direction pointing vertically out of the paper, and the second direction in the right diagram is a horizontal direction to the right. The power rectifying board 53 is electrically connected with the motor driving board 52. For example, the DC power output terminal on the power rectifying board 53 on the left side of the figure passes through the through hole on the bracket through a metal terminal and connects to the DC power of the motor driving board 52 on the right side. terminal connection.

The design of distribution on both sides reduces the volume of the entire controller part to half of the original size, realizes the minimization of the volume of the controller part, and effectively reduces the resistance to the air flow flowing inside the casing. The smaller volume of controller components can not only reduce the manufacturing cost, but also reduce the air flow resistance space in the casing, correspondingly increase the flow cross-sectional area of the air flow inside the casing, increase the wind pressure and wind speed of the air flow, and further protect the controller components. Excellent heat dissipation effect, so it can well guarantee the reliability of the controller components. In addition, the smaller volume is conducive to the integrated and centralized heat dissipation of the controller part and the switched reluctance motor body, without the need for separate heat dissipation for the motor and the controller part. The integrated centralized heat dissipation method improves the heat dissipation effect and reduces the heat dissipation cost at the same time. Moreover, the smaller size improves the convenience of the whole machine.

As shown in FIG. 5 , the switched reluctance motor body 4 further includes a first end cover 44 and a second end cover 45 located at both ends of the rotor 42 and the stator 43 . The first end cover 44 is located on the side of the switched reluctance motor body 4 facing the controller component, and the second end cover 45 is located on the side of the switched reluctance motor body 4 facing the air draft component. In particular, as shown in FIG. 6 , the first end cap 44 and the second end cap 45 are hollowed out. In this way, the air flow can flow into the switched reluctance motor body 4 approximately unobstructed.

Referring again to FIGS. 4 a and 4 b , the bracket 51 of the controller part 5 is disposed on the first end cover 44 . In this way, the wiring connection between the controller part and the motor is more convenient and simple.

Referring again to FIG. 7 , in the switched reluctance motor body, the stator 43 is located outside the rotor 42 , they are all arranged around the output shaft 41 , and a stator-rotor gap is formed between them. According to the principle of minimum reluctance, the switched reluctance motor generates a corresponding reluctance torque due to the different reluctance of the stator and rotor relative to different positions. The rotor has a structure in which rotor salient poles and rotor grooves alternate, and the stator has a structure in which stator salient poles and stator grooves alternate. For example, the stator has six stator grooves and the rotor has four rotor salient poles. The rotor groove and the stator groove form a large stator-rotor gap. Thus, a first air passage is formed between the casing 1 and the controller part 5 and the stator 43 of the switched reluctance motor body 4 , and a second air passage is formed in the gap between the stator 43 and the rotor 42 .

As shown in Figure 9, when the air flows through the controller components, part of the air flows into the first air passage, and the other part flows into the second air passage through the hollowed-out first end cover almost unobstructed, and then passes through the hollowed-out second air passage. The end cover merges with part of the air flowing through the first air channel, and finally flows out from the air outlet. The air duct is increased through the gap between the stator and the rotor, so that heat can be dissipated from both sides of the stator at the same time, which increases the heat dissipation area of the switched reluctance motor body, increases the air volume passing through the entire motor, and better integrates the switched reluctance. The heat of the motor body is dissipated quickly, so as to achieve an enhanced heat dissipation effect.

Referring again to Figures 2 and 3, the tubular wall of the housing is also provided with a power cord outlet 18 at the second end of the housing, adjacent to the mounting plate. As shown in FIG. 10 , the power cord 8 of the controller part extends in the space between the switched reluctance motor body and the casing, and is connected to an external power source together with the power cord 8 of the switched reluctance motor through a power cord outlet.

Various design parameters of the switched reluctance motor according to the embodiment of the present invention will be described in detail below with reference to FIG. 7 and FIG. 10 .

As shown in FIG. 7 , the switched reluctance motor body 4 has an outer diameter D, and the outer diameter D of the stator is between 60 mm and 90 mm. The relationship between the rotor outer diameter d and the stator outer diameter D satisfies d: D = 0.42-0.52, preferably d: D = 0.45-0.48. The pole arc coefficient of the stator α _stator = 0.39-0.48, preferably α _stator = 0.40-0.44; the pole arc coefficient of the rotor β _rotor = 0.30-0.40, preferably β _rotor = 0.33-0.36. Too large pole arc coefficient leads to a decrease in the high-speed output power of the motor and insufficient motor torque; too small pole arc coefficient leads to insufficient starting torque of the motor, which reduces the motor's working capacity with load, and the efficiency of the motor is not high, and the heat dissipation of the motor deteriorates.

As shown in FIG. 10 , the diameter of the opening at the upper first end of the trumpet-shaped outer shell 1 is d0 , and the diameter of the opening at the lower second end is d3 . The opening at the second end is larger than the opening at the first end. Therefore, the included angle between the tubular wall of the housing and the first direction is α=2˜5°. Considering the difficulty of the actual process and the smooth flow of the air, α is preferably 3.0-3.5°. The relationship between the diameter d3 of the opening at the second end of the casing 1 and the outer diameter D of the switched reluctance motor body is d3=1.1˜1.4D. Too small d3 affects the heat dissipation contact area of the airflow, and too large d3 is unfavorable for the rapid circulation of the airflow.

For example, the distribution range of the air inlets on the end wall at the first end of the casing is 0.75D˜1.2D.

The diameter of the inlet of the cavity for accommodating the fan blades is d2, where d2<d3. Preferably, d3 is 5 to 15mm larger than d2, that is, their relationship satisfies the following formula: d3=d2+5~15mm. The inner diameter of the cavity for accommodating the fan blade is d5, which is smaller than d3, so as to satisfy the high-speed operation of the fan blade and form a negative pressure zone.

As shown in Figure 10-11, the air inlet section diameter of the blade is d4, and d2<d4. Preferably, d4 is 1 to 5mm larger than d2, ie they satisfy the following formula: d4=d2+1~5mm. If d4 is too large or too small, it will affect the rapid circulation of the airflow. The diameter of the air outlet section of the fan blade is d1, and d4=0.33d1˜0.75d1. For example, d1=50-85mm. Too large air outlet section consumes more power of the motor, and too small air outlet section makes the heat dissipation effect of the motor poor.

In the first direction (vertical downward direction in FIG. 10 ), the housing reserves a space of b=5-20 mm at the first end for collecting air flow, that is, the air inlet component (such as the air inlet) and The distance between the controller parts along the first direction is in the range of 5mm to 20mm. b is preferably 8 to 12 mm. If b is too small, the amount of inflowing air will be insufficient, and if it is too large, the air flow rate will decrease.

The relationship between the air inlet area and the air outlet area of the casing is preferably: S _in : S _out = 1:3˜1:1.5. More preferably, the ratio of the air inlet area to the air outlet area is 1:2.5˜1:2.

In the embodiment of the present invention, the input power P1 of the switched reluctance motor body is above 2500W, and the motor speed is above 15000rpm. When the power consumption of the fan blades of the heat dissipation structure P2 = 0.025-0.06P1, the switched reluctance motor can achieve a better heat dissipation effect while ensuring 70% efficiency of the motor.

When the air outlet section diameter d1 of the fan blade is between 50 mm and 85 mm, the height h of the fan blade can be designed to be h=4.5-7.0 mm. Therefore, the height of the fan blades in the embodiment of the present invention is relatively small, but at the same time, it still has a relatively high operating speed, for example above 15000 rpm.

Table 1 below lists various parameters of the fan blades of the heat dissipation structure of the present invention and the fan blades of the existing heat dissipation structure.

Table 1

Under the condition that the outer diameter of the blades of the cooling structure is the same and the input power of the motor is the same, the height of the blades of the present invention is only 60% of the height of the blades used in general, and the input power consumed by the blades of the present invention is less power. The reduction in the height of the fan blades makes the space for installing the switched reluctance motor larger, which is conducive to the convenience of the whole machine. In addition, because the heat dissipation structure of the present invention can achieve enhanced heat dissipation effect, the actual temperature rise and output power of the switched reluctance motor of the present invention are better than those of the existing switched reluctance motor.

In the embodiment of the present invention, the heat consumption power of the controller components can reach more than 60W. Under the action of a general heat dissipation structure, the surface temperature of active devices can reach above 120°C. Through the heat dissipation structure of the present invention, after the external cold air flow enters the motor casing through the air inlet, it first flows through the controller part to dissipate heat preferentially, so that the temperature of the controller part is controlled below 100°C, thus improving the The temperature reliability of the controller components maintains the overall efficiency of the motor at a high level. After passing through the controller part, the air flow passes through the first air channel outside the stator and the second air channel in the gap between the stator and the rotor, so that the heat dissipated by the controller part and the switched reluctance motor body is quickly conducted away . This enhanced heat dissipation effect ensures the overall safety and reliability of the motor.

As shown in FIG. 12 , the casing 1 ′ of the switched reluctance motor according to another embodiment of the present invention may be truncated, for example, has an irregular octagonal cross-section, so the casing is called an octagonal truss. In other examples, the housing can also be a prism with other polygonal shapes in cross section.

The air inlet part is integrally formed with the pyramid-shaped casing, that is, the air inlet 21' is formed on the end wall of the casing. The air inlets 21', for example, have a rectangular shape and are regularly distributed on the end wall of the casing 1'.

The air outlet part 3' is formed on the side wall 11' of the pyramid-shaped casing, as shown in Fig. 12, the air outlet 31' is located on the side wall 11' and is close to the second end.

As shown in Figures 13a and 13b, an electric garden tool 200' according to an embodiment of the present invention includes a housing 201', a main body 202' driven by a motor, and a switched reluctance motor 100'. The switched reluctance motor 100' can be fixed at a specific position on the casing 201' of the electric garden tool 200', and the casing acts as a mounting plate for the motor at this time. The electric garden tool 200 ′ is, for example, a chain saw, and is mainly used for felling and making timber. The main body 202' is, for example, a link plate and a chain.

The second end of the pyramid-shaped housing 1' is disposed on the housing 201' of the electric garden tool, and the output shaft 41' of the switched reluctance motor body 4' passes through the hole on the housing. The output shaft 41' is connected with the main body 202' of the electric garden tool through a gear 46' to drive the main body to run.

The pyramid-shaped casing 1' and the casing 201' of the electric garden tool surround the switched reluctance motor body 4', the controller part 5', the ventilation part, etc., so as to form at least one cooling air duct.

The controller part 5' is arranged on the first end cover of the switched reluctance motor body 4' through its bracket, and is located between the air inlet on the casing and the switched reluctance motor body 4'. The power line 8' of the controller part extends along the motor body in the space between the switched reluctance motor body and the casing, and finally connects to an external power source together with the power line of the switched reluctance motor through a power line outlet. The centerline of the controller part 5' substantially coincides with the centerline of the switched reluctance motor body 4'. In addition, the motor driving board and the power rectifying board of the controller part 5' are arranged side by side on the bracket. In doing so, the volume of the controller component is reduced to half of its original size, and the resistance to air flow through it is reduced. In addition, because the position of the controller part and the switched reluctance motor is close, the line connection between the controller and the motor is more convenient and simple, which is beneficial to the convenience of the electric garden tool.

When the ventilation part is in operation, the air flow first flows through the controller part to dissipate heat, and then flows through the first air passage formed between the casing and the stator of the switched reluctance motor body and the first air passage in the gap between the stator and the rotor. The second air channel then quickly flows into the chamber under the action of the negative pressure zone formed in the cavity containing the blades due to the rapid rotation of the blades, and finally flows out through the air outlet. Therefore, the switched reluctance motor of the present invention has a larger heat dissipation area, larger air volume, more heat exchange air flow, and faster heat dissipation. In addition, this heat dissipation structure keeps the surface temperature of the controller component below 100° C. by preferentially dissipating heat from the controller component, so the reliability of the controller component can be well guaranteed.

The input power P1 of the electric garden tool in the example shown in Fig. 13a and 13b is more than 2500W, and the rotating speed of the fan blade of centrifugal work is more than 15000rpm, but its power consumption P2 is less (P2=0.025～0.06P1), the cooling effect better. In addition, the size of the fan blades is smaller, so that the space for installing the switched reluctance motor is larger, which is conducive to the convenience of the electric garden tool, and the actual temperature rise of the electric garden tool is lower. Furthermore, the air flow from the air outlet of the motor directly flows to other parts of the electric garden tool, which not only can further dissipate heat from the electric garden tool, but also has the effect of airflow to remove chips and dust.

In addition, the technical features disclosed above are not limited to the disclosed combination with other features, and those skilled in the art can also make other combinations among the technical features according to the purpose of the invention, so as to achieve the purpose of the present invention.

Claims (21)

1. A switched reluctance motor with heat dissipation structure, characterized in that, the switched reluctance motor comprises: a housing having opposed first and second ends and a tubular wall extending between the first and second ends; The air inlet component is arranged near the first end and has an air inlet; The air outlet component is arranged near the second end and has an air outlet; A switched reluctance motor body, disposed in the housing and having an output shaft extending along a first direction, a rotor and a stator disposed around the output shaft; a controller component, disposed in the housing and located between the air intake component and the switched reluctance motor body in the first direction; and The ventilation part is arranged on the output shaft and is located on the side of the switched reluctance motor body away from the controller part; At least one air duct is formed between the casing, the controller part and the switched reluctance motor body to dissipate heat from the controller part and the switched reluctance motor body. 2. The switched reluctance motor according to claim 1, wherein the controller component comprises: a bracket fixed in the housing; and The motor driving board and the power rectifying board are arranged side by side on the support in a second direction perpendicular to the first direction. 3. The switched reluctance motor according to claim 1, wherein the at least one air duct comprises a first air duct formed between the casing and the controller part and the stator, and a first air duct formed between the stator and the rotor the second airway. 4. The switched reluctance motor according to claim 1 or 2, characterized in that, the switched reluctance motor body further comprises a first end cover and a second end cover located at both ends of the rotor and the stator, the first end cover and the second end cap has a hollow form. 5 . The switched reluctance motor according to claim 4 , wherein the bracket of the controller component is disposed on the first end cover, and the bracket is a rectangular frame and the plane where it is located is parallel to the first direction. 6. The switched reluctance motor according to claim 1, characterized in that, the switched reluctance motor further comprises a mounting plate, the second end of the casing is arranged on the mounting plate and the output shaft of the switched reluctance motor body passes through holes in the mounting plate. 7. The switched reluctance motor according to claim 6, wherein the air outlet member is integrally formed with the mounting plate as a single part. 8. The switched reluctance motor according to claim 1, characterized in that the air outlet part is arranged on the tubular wall of the casing. 9. The switched reluctance motor according to claim 1, wherein the housing has a plurality of protrusions protruding inwardly from its tubular wall and extending along a portion of the tubular wall for attaching the switched reluctance motor body fixed in the housing. 10. The switched reluctance motor according to claim 9, wherein the plurality of protrusions are evenly distributed in the circumferential direction of the tubular wall. 11. The switched reluctance machine of claim 1, wherein the tubular wall forms a non-zero angle with the first direction. 12. A switched reluctance motor according to claim 11, characterized in that said angle is in the range of 2° to 5°. 13. A switched reluctance motor according to claim 11, wherein said angle is in the range of 3° to 4.5°. 14. The switched reluctance machine of claim 1, wherein the housing includes a cavity at the second end for receiving a draft member. 15. The switched reluctance motor according to claim 1, characterized in that, the ventilation component comprises a plurality of fan blades. 16. The switched reluctance motor according to claim 15, wherein the height of the fan blades in the first direction is in the range of 4.5mm to 7mm. 17. The switched reluctance motor according to claim 1, wherein the distance between the air inlet part and the controller part along the first direction is in the range of 5 mm to 20 mm. 18. A switched reluctance motor according to claim 17, wherein the distance is in the range of 8mm to 12mm. 19. The switched reluctance motor according to claim 1, characterized in that the ratio of the air inlet area to the air outlet area of the casing is between 1:3 and 1:1.5. 20. The switched reluctance motor according to claim 1, characterized in that the ratio of the air inlet area to the air outlet area of the casing is between 1:2.5 and 1:2. 21. An electric garden tool, characterized in that the electric garden tool comprises a switched reluctance motor according to any one of claims 1-20.

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