WO2019096223A1

WO2019096223A1 - Motor applicable to hand-held electrical tool, and same

Info

Publication number: WO2019096223A1
Application number: PCT/CN2018/115725
Authority: WO
Inventors: 赵晓; 周中亚; 毋宏兵; 吴海全; 卞印航; 李伟锋; 卢惠; 李辉; 张伟
Original assignee: 苏州宝时得电动工具有限公司
Priority date: 2017-11-15
Filing date: 2018-11-15
Publication date: 2019-05-23

Abstract

A brush motor (3), and a hand-held electrical tool using the motor (3). The motor (3) comprises: a one-piece stator (31); a rotor (32) provided within the stator (31); and an armature shaft (33) fixedly connected to the rotor (32). The outer diameter of the stator (31) is not greater than 58 mm. The range of an outer diameter ratio of the rotor to the stator is 0.6 to 0.7. The ratio of a maximum output power of the motor (3) to the volume thereof is greater than 8.5 W/cm3. The invention reasonably configures a size ratio of the stator to the rotor in the motor, and enhances the output capacity of the motor (3) compared with motors having the same size. The invention applies the motor (3) to a hand-held electrical tool to enhance the output power thereof while ensuring comfort when holding the tool.

Description

Motor for hand-held power tool and the hand-held power tool

Technical field

The present invention relates to a motor for use in a hand-held power tool, and a hand-held power tool using the same.

Background technique

The power tool is a working tool that is driven by a motor to move the working head to perform cutting, drilling, grinding, etc. on the workpiece. Hand-held power tools, such as angle grinders, swing machines, electric circular saws, etc., require the user to operate with a hand tool. The best working condition of this type of hand-held power tool is that the user can grasp the tool case with one hand, while the other hand can be used to assist the control or the movement direction, force and angle adjustment of the work head.

In a hand-held AC power tool such as an angle grinder, an oscillating machine or an electric circular saw, the motor is usually installed in the middle of the casing of the machine, and the user usually grasps the position in the middle of the casing during use, which is beneficial to the operation process. Balance control; the weight and size of the motor will directly affect the volume of the case, affecting the user's grip experience when using the power tool.

There are also hand-held DC power tools on the market, the motor is not installed in the holding position, which requires re-laying the weight of the tool so that the main weight source of the power tool is placed at the front and rear ends of the holding part during operation. This is beneficial to the balance control of the power tool operation and the labor saving.

For the hand-held AC power tool, in order to meet the working conditions, it is necessary to select a high-power motor, and accordingly, the size of the large-function motor will increase, and accordingly, the size of the casing portion accommodating the motor is increased accordingly. It will also increase the difficulty for the user to grasp, and it is easy to cause unstable grip and fatigue. If a small power motor is selected, although the size of the motor is reduced, the size of the casing housing the motor can be reduced, but the power of the power tool is also reduced, which cannot meet the user's demand for working conditions. It is necessary to meet the requirements of high-power working conditions and the handling operation. This is a contradiction that has long plagued the skilled person in the field.

At present, there are hand-held power tools using brushless motors. Because of the electronic commutation, there is no brush holder, and the volume of the brushless motor is usually smaller than that of the brush motor. However, the manufacturing cost of the brushless motor is much higher than that of the brush motor, especially the failure rate of the electronic commutator is very high. Therefore, the brushless motor will show higher than the brush regardless of the maintenance cost or the replacement cost. Motor.

A split stator motor is also used in the prior art to replace the conventional integral motor. The so-called split type motor is that the stator is divided into multiple pieces before winding, and each individual winding can increase the amount of winding, and then splicing or welding each piece after winding the line. In the conventional process, the split stator can coil more coils than the integral stator, thereby increasing the power of the motor. However, the manufacturing and assembly process of the split stator is more complicated than the one-piece stator, and the manufacturing cost is much higher, which is not suitable for widespread use in power tool products.

In addition, the wall thickness of the power tool casing and the clearance between the casing and the motor may have some influence on the casing to be held, but usually the material of the casing is ordinary plastic, if the wall thickness is reduced, the machine will be significantly reduced. The strength of the shell makes the stability of the power tool work greatly compromised. If the metal casing is used to make the casing, the weight of the whole machine will be significantly improved, and the user's grip and operability will be lowered. If the gap between the casing and the motor is reduced, the heat dissipation space around the motor will be reduced, which is not conducive to heat dissipation of the motor and the casing.

After research, it is found that the suitable size of the casing, especially the circumference of the casing, will make the user more comfortable to grip and not fatigue, and the grip is strong, the working head can be easily adjusted, and it is not easy to get rid of the hand. Due to the differences in ethnic characteristics, the palms of the East Asian yellow race are smaller than the European and American white races. After measurement, the length of Chinese male palm is usually between 175mm and 200mm, and the width is between 80mm and 90mm. The length of female palm is usually between 150mm and 180mm, and the width is between 65mm and 80mm. In order to adapt to the palm size of Chinese users and even Asian users, the optimal circumference of the hand-held power tool for the user to grasp is between 150mm and 185mm. Power tool manufacturers have been working on portable, hand-held AC power tools that are suitable for the user's grip.

Therefore, it is studied how to increase the power of the AC motor and the hand-held power tool using the AC motor while keeping the volume of the motor substantially constant, so that the hand-held motor tool can meet the working condition and accommodate the casing of the motor. It is also suitable for users to hold, which is an urgent problem that current technicians need to solve.

Summary of the invention

Based on this, it is necessary to provide a brushed motor having a low cost, high power, small size, and integral stator.

The invention is achieved by the following technical solution: the motor used in the hand-held power tool comprises an integral stator; a rotor arranged in the stator; the armature shaft is fixedly connected with the rotor and connected with a commutator; The commutator is electrically connected; the outer diameter of the stator is not more than 58 mm, the ratio of the outer diameter of the rotor to the outer diameter of the stator is in the range of 0.6 to 0.7, and the ratio of the output power to the volume of the motor is greater than 8.5 W/cm ³ .

In one of the embodiments, the outer diameter of the stator is no more than 50 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.6 to 0.65.

In one of the embodiments, the yoke of the stator has a width ranging from 3.6 mm to 4.2 mm.

In one of the embodiments, the length of the stator along the axial direction of the armature shaft is not less than 40 mm.

In one of the embodiments, the diameter of the armature shaft is not less than 7.5 mm.

In one of the embodiments, the diameter of the armature shaft ranges from 7.5 mm to 9 mm.

The invention increases the ratio of the stator to rotor outer diameter of the motor to 0.6 or more, and increases the ratio of the output power of the motor to the volume of 8.5 W/cm ³ or more, thereby enhancing the output capability of the motor of the same size.

The motor is used in a hand-held power tool, the motor comprises: a stator, which is integral; the rotor is coaxially sleeved in the stator; the armature shaft is fixedly connected with the rotor; the commutator is fixedly connected with the armature shaft The brush is electrically connected to the commutator; the outer diameter of the stator is not more than 58 mm, the yoke width of the stator ranges from 3.5 mm to 4.2 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.618 to 0.65.

In one of the embodiments, the outer diameter of the stator is no more than 55 mm, the yoke width of the stator ranges from 4.1 mm to 4.3 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.618 to 0.636.

In one of the embodiments, the stator has an outer diameter of 55 mm, the stator has a yoke width of 4.2 mm, and the rotor outer diameter to stator outer diameter ratio ranges from 0.636.

In one of the embodiments, the outer diameter of the stator is no more than 50 mm, the yoke width of the stator ranges from 3.8 mm to 4.2 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.62 to 0.64.

In one of the embodiments, the outer diameter of the stator is 50 mm, the yoke width of the stator ranges from 3.8 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.62.

In one of the embodiments, the outer diameter of the stator is no more than 46 mm, the yoke width of the stator ranges from 3.5 mm to 3.7 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.62 to 0.65.

In one of the embodiments, the outer diameter of the stator is 46 mm, the yoke width of the stator is 3.6 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator is 0.62.

The invention provides a hand-held power tool suitable for holding and comfortable operation. The hand-held power tool has the above-mentioned integral motor, and further comprises a casing; the transmission mechanism transmits the torque of the armature shaft to the output shaft; the casing has a grip The inner edge of the grip portion at least axially houses the stator, and the outer periphery of the grip portion is used for gripping, and the peripheral circumference of the grip portion ranges from 150 mm to 185 mm, and the output power of the motor and the periphery of the grip portion are The ratio of circumference is greater than 5.1 W/mm.

In one of the embodiments, the peripheral circumference of the grip portion ranges from 165 mm to 182 mm, and the outer diameter of the stator is no more than 50 mm.

In one of the embodiments, the ratio of the power of the motor to the peripheral circumference of the grip is greater than 5.2 W/mm.

In one of the embodiments, the ratio of the power of the motor to the peripheral circumference of the grip is greater than 5.35 W/mm.

In one of the embodiments, the peripheral circumference of the grip portion ranges from 165 mm to 170 mm, the outer diameter of the stator is not more than 46 mm, and the length of the stator along the axial direction of the armature shaft is not less than 50 mm.

In one of the embodiments, the ratio of the output power of the motor to the peripheral circumference of the grip is greater than 5.15 W/mm.

Preferably, the diameter of the armature shaft ranges from 7.5 mm to 9 mm.

In one embodiment, the casing includes a fuselage and a head casing, the fuselage is fixedly coupled to the head casing, the grip portion is on the fuselage, the fuselage includes a heat dissipating portion, and the grip portion is located between the head casing and the heat dissipating portion. The cross-sectional area of the grip portion is smaller than the cross-sectional area of the heat dissipating portion.

In one of the embodiments, the material of the fuselage is a plastic that has undergone a granulation process.

In one embodiment, the heat dissipating portion has an air inlet port on the side surface, and the air inlet port extends from one end of the heat dissipating portion to the other end along the length direction of the heat dissipating portion.

In one embodiment, the head casing has an air outlet, and the ratio of the area of the air inlet to the area of the air outlet is not less than one.

In one embodiment, the casing includes a connecting portion, and the holding portion is connected to the heat radiating portion through the connecting portion.

In one embodiment, the hand-held power tool further includes a component disposed at the rear end of the fuselage, a tail cover sleeved at the rear end of the fuselage, and a guiding member between the fuselage and the tail cover, and the tail cover is provided with The tuyere, the guiding member and the tail cover enclose an air inlet passage, and the air inlet passage communicates with the air inlet and the motor, and the cooling air entering the air inlet port flows along the air inlet passage to the motor, and the component is located outside the air inlet passage.

In one of these embodiments, the inlet passage and components are located on different sides of the guide.

In one of the embodiments, the guide member is disposed on the body.

In one of the embodiments, the guide member is integrally formed with the body, or the guide member is fixedly coupled to the body.

In one of the embodiments, the guide member is disposed on the tail cover.

In one of the embodiments, the guide member is in the form of a plate.

In one of the embodiments, the guide member is parallel to the axial direction of the motor.

In one of the embodiments, the guide member extends in the axial direction of the motor, and the guide member has a curved surface in a section perpendicular to the axial direction of the motor.

In one of the embodiments, the air inlet passage extends in the axial direction of the motor.

In one embodiment, the air inlet on the tail cover includes a first air inlet that allows cooling air to enter the air inlet passage in the axial direction of the motor, and a second air inlet that enters the air inlet passage in a direction perpendicular to the axial direction of the motor. Inlet.

Compared with the prior art, the invention increases the ratio of the output power of the hand-held power tool to the holding circumference to 5.1 W/mm or more, and the output power can fully satisfy the hand tool under the condition of ensuring the comfort of the grip. Job requirements. This not only facilitates the user to use the hand-held power tool for a long time, is not easy to fatigue, and improves work efficiency. In addition, the cooling air entering the air inlet flows along the air inlet passage to the motor, and the components are located outside the air inlet passage, so that the cooling air entering the air inlet does not flow through the components, thereby preventing the cooling air from being The components block and form a vortex, so that the cooling air entering the air inlet flows more toward the motor, which improves the effective cooling air volume and cooling efficiency.

A hand-held power tool includes: a housing; an output shaft for mounting the working head, the output shaft is mounted in the housing and extends out of the housing; the transmission mechanism is installed in the housing, and the transmission mechanism is connected to the output shaft The motor is installed in the housing, comprising: a stator, the stator is integral; the rotor is coaxially sleeved in the stator; the armature shaft is fixedly connected with the rotor; the armature shaft is connected with the transmission mechanism, and the transmission mechanism is The rotary motion of the armature shaft is converted into a reciprocating motion of the output shaft around its own axis; wherein the outer diameter of the motor ranges from 40 mm to 50 mm, and the bare metal idle speed of the motor is greater than 20000 rpm, and the motor output power The ratio to volume is greater than 2 W/cm3.

In one of the embodiments, the housing is provided with a grip portion having an outer circumference of 150 mm to 200 mm.

In one of the embodiments, the ratio of the output power of the motor to the peripheral circumference of the grip is greater than 0.8 W/mm.

In one of the embodiments, the ratio of the output power of the motor to the peripheral circumference of the grip is greater than 0.95 W/mm.

In one of the embodiments, the bare metal no-load speed of the motor is greater than 30,000 rpm, and the motor output power to volume ratio is greater than 5.5 W/cm3.

In one embodiment, the housing is provided with a grip portion having an outer circumference of 150 mm to 200 mm, and the ratio of the output power of the motor to the peripheral circumference of the grip portion is greater than 2.0 W/mm.

In one of the embodiments, the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.60 to 0.70, and the width of the stator yoke is from 3.5 to 4.0 mm.

In one of the embodiments, the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.65 to 0.70, and the width of the stator yoke is from 3.5 to 3.8 mm.

In one of the embodiments, the stator has an outer diameter of 46 mm, a yoke width of 3.6 mm, and a rotor outer diameter to stator outer diameter ratio of 0.62.

In one of the embodiments, the axial length of the motor ranges from 45 mm to 60 mm.

DRAWINGS

The above and other objects, aspects and advantages of the present invention will become apparent from

Figure 1 is a schematic view of the front view of the angle grinder.

Figure 2 is a cross-sectional view showing the internal structure of the angle grinder.

Figure 3 is a schematic view of the angular grinding in and out of the wind.

Figure 4 is a cross-sectional view taken along line I-I of Figure 2;

Figure 5 is a schematic view of a conventional motor.

Figure 6 is a cross-sectional view taken along line II-II of Figure 2;

Figure 7 is a schematic diagram of a high slot full rate motor in which the armature shaft diameter is increased.

Figure 8 is a cross-sectional view taken along line III-III of Figure 1.

Figure 9 is a schematic exploded view of the angle grinder.

Figure 10 is a perspective view of the swinging machine of the present invention.

Figure 11 is a cross-sectional view taken along line IV-IV of Figure 10.

Figure 12 is a perspective view of the transmission mechanism of the swinging machine of the present invention.

Detailed ways

The above described objects, features and advantages of the present invention will become more apparent from the aspects of the appended claims. Numerous specific details are set forth in the description below in order to provide a thorough understanding of the invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention, and thus the invention is not limited by the specific embodiments disclosed below.

Referring to Figures 1, 2 and 3, in one embodiment of the invention, the hand-held power tool is an angle grinder 100. It can be understood that a hand-held power tool with a similar structure such as an oscillating machine, an electric circular saw, a straight grinder, etc. can be considered as a modification of the angle grinder, and will not be described herein. The angle grinder 100 has a hollow casing 1 in which a motor 3 and a transmission mechanism 4 are housed, and an air flow passage for cooling is provided. The casing 1 includes a fuselage 11, a tail cover 150 and a head casing 12. The fuselage 11 and the head casing 12 are fixedly connected by screws, thereby ensuring the stability of the hand-held angle grinder during operation, and the tail cover 150 is set and machined. At the end of the body. The motor 3 is disposed in the body 11, and the transmission mechanism 4 is disposed in the head casing 12.

The motor 3 is a brushed AC motor. In this embodiment, a single-phase series motor is used. The stator 31 includes a stator core 311 and a field winding 312. The rotor 32 includes a rotor core 321, an armature winding 322, and a commutator. 37 and the armature shaft 33, an insulating wrap shaft or the like is usually disposed between the rotor core and the armature shaft. The field winding 312 and the armature winding 322 are connected in series by a brush 34 and a commutator 37.

The cooling fan 35, the motor 3, the brush 34, the circuit board (not shown), and the switch 36 are sequentially housed in the body 11 along the axial direction of the armature shaft 33, and the trigger button 36a of the switch 36 is extended to the body 11. External for easy operation. The cooling fan 35 is adjacent to the body 11 of the head casing 12, and the brush 34 is disposed on the brush holder connected to the body 11, and is electrically connected to the commutator 37 of the motor 3.

The stator 31 of the present embodiment is an integral stator. Different from the split stator in the prior art, each laminated piece of the stator in the axial direction is hollow and integral, and a plurality of laminated pieces are pressed and welded together to form Hollow monolithic stator. The stator 31 is fixed in the body 11, and the rotor 32 and the armature shaft 33 driven by the rotor 32 are located inside the stator 31, and the armature shaft 33 extends from the end of the cooling fan 35 outside the body 11 to enter the head shell. 12. The body 11 has an approximately cylindrical shape extending along the axial direction of the armature shaft 33, and the extending axis of the body 11 is coaxial with the axis of the armature shaft 33.

The body 11 includes a first cylindrical portion 110 for housing the cooling fan 35 and connected to the head case 12, a second cylindrical portion 112 connected to the first cylindrical portion 110, and a commutator 37, a circuit board, and a switch. The third tubular portion 130 of the electronic device 36; wherein the second tubular portion 112 serves as a grip portion, and houses the stator 31 of the motor 3 and a portion of the rotor 32 located inside the stator 31. The diameter of the second tubular portion 112 is smaller than the first one. The diameters of the tubular portion 110 and the third tubular portion 130 are designed such that the grip portion gripped by the user during operation is the thinnest portion of the body 11, and the brush 34 and the cooling fan 35 are respectively located on both sides of the grip portion.

The cooling fan 35 is fixedly connected to one end of the armature shaft 33 near the head casing 12, and generates a negative pressure when rotating, and the cooling air outside the casing 1 is sucked through the air inlet 1151 of the tail cover 150, and flows through the switch 36, the circuit board, and the motor. 3. The cooling fan 35 is discharged from the air outlet 121 of the head casing 12.

In this embodiment, since the diameter of the first cylindrical portion 110 is larger than the diameter of the second cylindrical portion 112 as the grip portion, the diameter of the cooling fan 35 disposed in the first cylindrical portion 110 may also be set larger than the diameter of the stator 31, and cooled. The air intake is large and the cooling effect is good. In the present embodiment, the first tubular portion 110 includes an enlarged portion 117 and a transition portion 118 that is connected to the second tubular portion 112 and has a curved surface. The angle α between the transition portion 118 and the grip portion is close to 120°. The setting of the angle α allows the palm of the hand to be engaged with the transition portion 118 when the user holds the operation, so that the transition portion 118 provides stable support for the gripping operation, thereby making the operation more comfortable. The enlarged portion 117 is used for a connection that matches the shape of the head shell 12.

It is also conceivable by those skilled in the art that the diameter of the cooling fan 35 is set to be equal to the diameter of the stator 31, and the diameter of the first cylindrical portion 110 may also be set to be substantially equal to the diameter of the grip portion 112.

Referring to further FIGS. 3 and 6 , the third tubular portion 130 includes a connecting portion 116 connected to the grip portion, and a heat dissipating portion 115 connected to the connecting portion, and the heat dissipating portion 115 provides a passage for the cooling air to enter the air body. The low temperature air outside the casing can enter the casing. The brush 34 is disposed in the connecting portion 116, and may be partially disposed in the connecting portion 116, partially disposed in the heat radiating portion 115, or may be disposed in the heat radiating portion 115. The heat radiating portion 115 is disposed on the body 11 and communicates with the airflow inside the grip portion. The airflow in the heat radiating portion 115 can flow into the grip portion to take away the heat generated by the motor 3. The thickness of the housing of the grip portion and the heat dissipating portion 115 is approximately the same, and the cross-sectional area of the inner edge of the grip portion may be smaller than the cross-sectional area of the inner edge of the heat dissipating portion 115. When the airflow enters the grip portion having a small cross-sectional area from the heat radiating portion 115 having a large cross-sectional area, the flow velocity of the airflow in the grip portion is increased, and the heat dissipation effect on the grip portion and the motor 3 is enhanced. The cooling air enters from the air inlet 1151 of the heat radiating portion 115, flows through the gap between the grip portion and the motor 3, takes away heat of the motor 3 and the grip portion, and finally flows out from the air outlet 121 of the head casing 12. The cooling air mainly dissipates heat from the motor 3 and the grip portion, reduces the temperature of the motor 3 and the grip portion, and prevents the internal temperature of the hand-held angle grinder from being too high, thereby affecting the working and service life of the components therein. The head casing 12 and the transmission mechanism 4 are also dissipated as they flow through the head casing 12. When the tail cover 150 is sleeved on the body 11, the heat dissipating portion partially overlaps with the tail cover.

The air inlet 1151 and the tail cover 150 are respectively provided with air inlets 1151. The air inlets 1151 include a plurality of slots (not labeled) extending along the axial direction of the heat dissipation portion 115 and spaced apart from each other in the radial direction. As a cooling passage, it enters the inside of the casing with low temperature air. In the present embodiment, the air inlet 1151 extends from one end of the heat radiating portion 115 to the other end. On the inner side of the casing of the tail cover 150, there are respectively inserted and inserted dustproof sheets 22, and the dustproof sheets 22 are provided with a fine grid for external airflow, but can prevent dust having a certain granularity from entering. The inside of the casing; the dustproof piece 22 is arranged to facilitate cleaning and installation, and can effectively prevent dust from entering the air inlet 1151.

Referring to FIG. 4, the motor 3 is disposed in the body 11, wherein the stator 31 is interference-fitted with the fixing member 113 in the body 11, ensuring that there is no relative movement between the stator 31 and the body 11, wherein the fixing member 113 and the holding portion are The edges are integrally formed. The rotor 32 is disposed in the stator 31, and both ends of the armature shaft 33 are respectively installed in the first bearing 331 and the second bearing 332, wherein the first bearing 331 is disposed in the first bearing chamber 111 in the body 11, and the second The bearing 332 is disposed in the second bearing chamber 122 of the head case 12.

On the fuselage 11, a first mounting portion having approximately the same contour is extended from the first tubular portion 110, and the head casing 12 has a second mounting portion having approximately the same contour, and the first mounting portion is identical to the second mounting portion when assembled The shafts are connected together, and then the body 11 and the head case 12 are fixedly connected by screws. Typically, during design and production, the first mounting portion is coaxial with the first bearing chamber 111, and the second mounting portion is also coaxial with the second bearing chamber 122, thereby securing the first bearing chamber 111 and the second bearing chamber 122 remains coaxial.

In order to ensure that the fuselage 11 has sufficient strength to prevent the first bearing chamber 111 and the fixing member 113 from undergoing a large deformation, affecting the coaxiality of the stator 31 and the rotor 32, preferably, the material of the fuselage 111 is subjected to a granulation process. Plastics, by increasing the glass fiber content, the tensile strength is greater than 200Mpa, the bending strength is greater than 250Mpa, the moisture absorption rate is less than 2%, and the strength stability is high. The dimensional stability of the plastics that meet the above parameters can prevent large deformation of the fuselage and affect the coaxiality of the stator and the rotor.

The transmission mechanism 4 located in the head casing 12 includes an angled bevel gear set including a tapered pinion 41 coupled to the armature shaft 33, a conical bull gear 42 coupled to the output shaft 2, an output shaft 2 and an armature The shaft 33 is disposed substantially vertically.

The diameter of the second tubular portion 112 determines the circumference of the grip portion, and the circumference of the grip portion directly affects the grip feeling of the user. If the circumference of the grip portion is too long, the grip of the user is unstable, and the operation is easy. fatigue. According to the test, the length of the Chinese male palm is usually between 175mm and 200mm, and the width is between 80mm and 90mm. The length of the Chinese female palm is usually between 160mm and 180mm, and the width is between 65mm and 80mm. When grasping the hand-held angle grinder, the length of the palm surrounds the grip portion. Generally, the circumference of the grip portion should be slightly larger or slightly smaller than the length of the palm. When the finger is too large, the finger grip is not complete, which may result in unstable grip, and the thumb is too small. Stacking on other fingers will also reduce the grip. The second tube portion also houses the motor. Considering the support structure of the motor, the air passage, and the like, the diameter of the motor should be no more than 58 mm.

Define the volume of the motor V = π (D / 2) ² L / 1000, where D is the stator diameter, L is the axial length of the motor, the unit is mm, the unit of the motor volume V is cm ³ . The axial length L of the motor 3 is defined by the length of the stator core 311 or the length of the rotor core 321 , and generally the axial length L of the stator core 311 and the rotor core 321 are the same.

When the load is idling, the rotation speed of the motor 100 of the angle grinder 100 is required to reach about 38000 rpm. The power input from the grid to the angle grinder 100 during operation is defined as the input power P1; the power P2 input to the working object by the angle grinder 100 is defined as the output power, P2=P1-P, where P is defined as loss, including tool heat loss, Wind power, friction loss, etc., the output power of the motor 3 is P2.

Since the output power P2 of the motor 3 is proportional to the diameter D of the motor 3, the axial length L of the motor 3, the rotational speed of the motor, and the slot full rate of the motor. The speed of the motor is basically not affected by the safety regulations and the life of the motor. If it is considered to increase the diameter D of the motor 3 in order to increase the output power P2 of the motor, it is necessary to increase the diameter of the grip portion correspondingly, which makes it difficult for the user to grasp.

The longer the axial length L of the motor 3 is, the larger the volume V of the motor 3 is, the larger the magnetic field strength is, and the larger the output power P2 of the motor 3 is.

The rotor core 321 and the stator core 311 are usually laminated stacks which are stacked and welded in the axial direction with an appropriate number of metal laminations, and the main component is iron, so it may also be referred to as an iron core. Different from the split stator, each laminated piece of the monolithic stator in the axial direction is hollow and integral, rather than being spliced by a plurality of small laminations. Typically, the thickness of the metal lamination is 0.5 mm, and the axial length of the stator core 311 and the rotor core 321 is the total thickness of the appropriate number of lamination stacks. The outer profile of the unitary stator may be arranged in a circular, elliptical, rectangular or other shape suitable for accommodation in the casing.

Each metal lamination of the stator core 311 is provided with a notch 313, and each metal lamination of the rotor core 321 is provided with a notch 323; thus, a lamination stack formed by a metal lamination of the stator core 311, respectively The lamination stack formed by the metal laminations of the rotor core 321 is respectively formed with slots, and coils are respectively wound in the stator core slots and the rotor core slots.

Referring to Figure 5, there is a cross section of a conventional motor in which the coils wound in the stator and rotor slots are substantially sparse, and usually a screw hole 315 for fixing the stator to the casing is provided, and the screw holes are provided. The presence of 315 reduces the stator yoke width 311a, which in turn affects the stator core slot size and the coils therein. However, in FIG. 4, the stator 31 and the body 11 of the embodiment of the present invention adopt different fixing methods, the screw holes are eliminated, the size of the stator core slot is not affected, and the number of turns of the coil is large and the winding is tight. . The result is that the more the coil area is wound in the unit slot area, the higher the tank full rate, and the greater the magnetic field strength of the motor, the larger the output power P2 of the motor.

After increasing the lamination stack length and the slot full rate of the motor 3, the overall weight of the motor 3 is increased, and in particular, the weight of the rotor 32 is increased, which increases the load on the armature shaft 33 of the rotor 32. The rotor 32 of the motor is disposed in a space surrounded by the stator 31, and has a radial gap of substantially 0.5 mm or less with the stator 31. Therefore, the coaxiality between the rotor and the stator is very high, and slight deviation causes the rotor to rotate. Rubbing against the stator, or called a broom. Brooms generate a lot of heat and can burn out the motor or cause more serious accidents.

When the armature shaft 33 of the rotor 32 encounters a load, the armature shaft 33 generates a certain bending deformation, and if the load is increased, the amount of deformation increases. In order to prevent the armature shaft 33 from causing a large deformation to cause the broom, it is necessary to reduce the amount of deformation of the armature shaft 33 when subjected to the load, that is, to reduce the deflection of the armature shaft 33. The diameter of the armature shaft 33 needs to be increased without changing the material of the armature shaft 33.

It has been verified by tests that when the diameter of the armature shaft is increased by 5%, the deflection of the armature shaft 33 is reduced by 17.7%; when the diameter of the armature shaft 33 is increased by 10%, the deflection of the armature shaft is reduced by 31.7%; When the diameter of the armature shaft is increased by 15%, the deflection of the armature shaft is reduced by 42.8%. Therefore, by appropriately increasing the diameter of the armature shaft 33, the deflection of the armature shaft 33 can be reduced to a reasonable range.

Referring to Fig. 7, when the diameter of the rotor 32 is constant, that is, the diameter of the rotor lamination stack remains unchanged, the diameter of the armature shaft 33a is increased to reduce the size of the rotor yoke width 322a, thereby reducing the magnetic flux of the rotor, thereby Reduce the output power of the motor; the diameter of the armature shaft increases, and the magnetic flux of the rotor decreases, which is a contradiction between the two. The invention proposes that while improving the winding process of the motor, the carrying capacity of the armature shaft 33 and the output power of the motor should be ensured at the same time.

Table 1

Table 1 shows the comparison of the data for the impact of the armature shaft diameter on the motor power performance when the speed of the motor meets the requirements of the hand angle grinder at 38000 rpm. Since the test machine is difficult to stabilize the speed at 38,000 rpm, the actual test speed will be slightly greater than 38000 rpm, so that the measured result is within an acceptable range. In addition, since the test motor requires a carrier to fix the motor and apply a load to the motor, the motor is tested in a hand-held power tool, such as in an angle grinder.

As shown in Table 1, the reference sample has an armature shaft diameter of 7.5 mm and a power of 975 W. The four measurement samples are compared to the reference sample, wherein the diameter of the armature shaft increases equally. After testing, the diameter of the reference armature shaft is increased by 7.5 mm and the diameter of the motor is increased by 1%. When the diameter of the armature shaft is 8mm and the diameter is 8mm to 1mm, the loss rate of the motor power is below 3%. Compared with the working requirements of the hand-held angle grinder, the loss rate is within the acceptable range. When the diameter of the armature shaft exceeds 9.5 mm, the loss of motor power will increase, and the motor power is only 85% of the reference sample. In this embodiment, the diameter of the armature shaft is not less than 7.5 mm, in order to ensure the motor power and the bearing capacity of the armature shaft; in one embodiment, the diameter of the armature shaft 33 ranges from 7.5 mm to 9 mm, so that the motor can be ensured. The power meets the demand and ensures that the motor works properly.

On the stator lamination, the area between the stator slot and the outer diameter of the stator is defined as the stator yoke width 311a. The stator yoke width 311a affects the magnetic flux of the stator. The larger the stator yoke width 311a is, the larger the magnetic flux is, and the larger the output power P2 of the motor is. . A slot for winding the coil and an inner diameter hole embedded in the rotor are required on the stator lamination; referring to Fig. 5, the stator lamination usually also leaves a screw hole 315 for fixing the stator to the casing.

Referring to FIG. 4, in order to increase the area of the stator slot, the present embodiment changes the cooperation between the stator 31 and the body 11 into an interference fit, cancels the screw hole, and increases the width of the stator yoke width 311 to 3.6 mm or more. . In an alternative embodiment, the range of stator yoke widths is set between 3.6 mm and 4.2 mm to further increase the slot size for winding more coils to increase magnetic flux.

The inner diameter hole of the stator 31 is used to embed the rotor 32, and a gap is maintained between the stator 31 and the rotor 32 to ensure that the rotor does not rub against the stator when the rotor rotates at a high speed, the inner diameter hole of the stator 31 increases, and the diameter of the rotor 32 can be correspondingly increased. Can increase the magnetic flux of the rotor. However, an increase in the inner diameter of the stator 31 also reduces the size of the stator yoke width 311a, which in turn reduces the magnetic flux of the stator 31. The inner diameter of the stator increases, and the magnetic flux of the stator decreases, which in turn is a contradiction between objective and objective.

For the above two pairs of objective contradictions, the present invention studies the influence of the stator and rotor outer diameter ratios on the output power of the motor, and solves the relationship between the power and the outer diameter of the stator and the rotor.

Table 2 shows the variation of the motor power to volume ratio under the condition that the stator diameter is 50 mm and the axial length of the motor is 50 mm, the stator yoke width is different, and the stator and rotor outer diameter ratios are changed. The values in Table 2 show the same motor volume, the stator yoke width increases or the stator and rotor outer diameter ratios increase, and the power of the motor exhibits an undulating change. When the ratio of the outer diameter of the stator to the rotor is 0.62, the ratio of power to volume reaches a maximum value of 10.05 when the stator yoke width is 3.8 mm. When the stator yoke width is 4 mm, the ratio of power to volume is 0.62 in the stator to rotor outer diameter ratio. The maximum value of 10 was reached. In Table 2, the yoke width of the stator ranges from 3.8 mm to 4.2 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.62 to 0.64, and the power-to-volume ratio of the motor is relatively large, especially the yoke width of the stator. The range is 3.8mm, and the motor's power-to-volume ratio is the largest when the ratio of rotor outer diameter to stator outer diameter is 0.62.

Table 2

The ratio of the power to the volume of the motor is a value that reflects the power output efficiency of the motor. Under the same volume, the larger the ratio, the greater the motor power. The power of the motor in Table 2 refers to the power value when the motor speed reaches 38000 rpm. The ratio of the stator to the outer diameter of the rotor and the width of the stator yoke all affect the ratio of motor power to volume. The larger the stator and rotor outer diameter ratio is, the larger the rotor size is, and the stator yoke width 311 is correspondingly reduced; vice versa. The larger the stator yoke width, the smaller the stator slot and rotor size, and vice versa. Reasonable design, rotor outer diameter ratio and yoke width can make the motor power reach a larger value.

In the present embodiment, the ratio of motor power to volume is selected to be greater than 8.5, so that the grip angle of the hand-held angle grinder is comfortable and more powerful under the same motor volume, especially the same stator diameter.

Referring to Table 2, the same motor volume, the stator yoke width increases or the stator and rotor outer diameter ratios increase, and the power of the motor exhibits an undulating change. In one embodiment, the stator to rotor outer diameter ratio ranges from 0.6 to 0.7 and the outer diameter of the stator is no greater than 58 mm. Preferably, the outer diameter of the stator is no more than 50 mm. In another alternative embodiment, the stator to rotor outer diameter ratio ranges from 0.6 to 0.65 and the yoke width ranges from 3.6 mm to 4.2 mm. The yoke width is excessively reduced to reduce the area of the slot, resulting in a reduction in the amount of stator winding. Within this size range, the power of the motor fluctuates within a range close to the maximum. At this time, the axial length of the motor, that is, the length of the stator along the axial direction of the armature shaft is set to be not less than 40 mm, and the setting range is 45 mm to 60 mm, preferably 55 mm.

In one embodiment of the invention, the ratio of the output power P2 of the motor 3 to the peripheral circumference of the angle grinder grip is greater than 5.1 W/mm, where the output power P2 is the maximum output power of the angle grind input to the work object. The grip of the hand-held angle grinder 1 has a peripheral circumference of 150 mm to 185 mm. In order to allow sufficient space inside the grip to accommodate the motor 3, the outer diameter of the stator 31 is no more than 58 mm.

In another alternative embodiment, the peripheral circumference of the grip portion of the hand-held angle grinder 100 is set to 165 mm to 182 mm, and the outer diameter of the stator 31 is not more than 50 mm. The axial length L of the motor is not less than 40 mm, and the ratio of the output power P2 of the motor 3 to the peripheral circumference of the angle grinder grip portion is larger than 5.2 W/mm.

In still another alternative embodiment, the ratio of the output power P2 of the motor 3 to the peripheral circumference of the angle grinder grip is greater than 5.35 W/mm.

The material of the head shell 12 of the hand-held angle grinder 100 is usually made of metal, mainly aluminum, and has high strength. When the weight of the rotor 32 increases, the second bearing chamber 122 does not undergo large deformation, affecting the rotor 32 and the stator. The coaxiality of 31. The body 11 is made of plastic, and the first bearing chamber 111 is integrally formed on the body 11. In order to ensure sufficient strength of the body 11, the first bearing chamber 111 and the fixing member 113 are prevented from being deformed greatly, and the stator is affected. Concentricity with the rotor. Preferably, the material of the fuselage 11 is a granulated plastic. By increasing the glass fiber content, the tensile strength is greater than 200 MPa, the bending strength is greater than 250 MPa, the moisture absorption rate is less than 2%, and the strength is stable. High sex. The dimensional stability of the plastics that meet the above parameters can prevent large deformation of the fuselage and affect the coaxiality of the stator and the rotor.

Both the grip portion and the heat radiating portion 115 have a substantially cylindrical shape, and extend in the axial direction of the armature shaft 33, and the longitudinal direction of the grip portion and the heat radiating portion 115 is the same as the axial direction of the armature shaft 33.

When designing the air inlet and outlet, the designer needs to consider the area relationship between the two, usually the air inlet area is larger than the air outlet. The larger the air inlet, the larger the ideal air intake, but if it is too large, the cooling air will lose its guidance, forming a flow around the air inlet, entering from the air inlet and then flowing out from the air inlet, or the cooling air cannot be smooth. The ground discharge causes the cooling efficiency to decrease. In the present embodiment, the ratio of the area of the air inlet to the area of the air outlet is greater than 1, and the preferred range is 1.2 to 1.4.

table 3

In one embodiment, the peripheral portion of the grip of the hand-held angle grinder 100 has a circumference of 165 mm to 170 mm, the length of the stack of laminations is not less than 50 mm, and the outer diameter of the stator is no more than 46 mm. The ratio of the output power P2 of the motor 3 to the peripheral circumference of the angle grinder grip is greater than 5.15 W/mm. The diameter of the armature shaft is set to be not less than 7.5 mm.

Table 3 shows the variation of the motor power to volume ratio under different conditions of stator and rotor outer diameter when the stator diameter is 46 mm. Similar to the test results of Table 2, the values in Table 3 show the same motor volume, the stator yoke width increases or the stator and rotor outer diameter ratios increase, and the power of the motor exhibits an undulating change. When the ratio of the outer diameter of the stator to the rotor is 0.62, the ratio of power to volume reaches a maximum value of 10.2 when the stator yoke width is 3.6 mm; when the stator yoke width is 4 mm, the ratio of power to volume is 0.62 in the stator to rotor outer diameter ratio. The maximum value of 8.6 was reached. In Table 3, the yoke width of the stator ranges from 3.5 mm to 3.7 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.62 to 0.65, and the power-to-volume ratio of the motor is relatively large, especially the yoke width of the stator. The range is 3.6mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator is 0.62. The ratio of power to volume of the motor is the largest.

In another alternative embodiment, the diameter of the armature shaft is set between 7.5 mm and 9 mm, preferably 8 mm.

In one embodiment, the stator diameter of the motor is 55 mm, the peripheral circumference of the grip portion of the angle grinder for housing the motor is larger, and the power of the motor is also increased. Table 4 shows different stators when the stator diameter is 55 mm. The yoke width is the change of the motor power to volume ratio under the condition that the stator and rotor outer diameter ratios are changed. With the same motor volume, the stator yoke width increases or the stator and rotor outer diameter ratios increase, and the power of the motor exhibits an undulating change. In Table 4, the yoke width of the stator ranges from 4.1 mm to 4.3 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.618 to 0.636, and the power-to-volume ratio of the motor is relatively large, especially the yoke width of the stator. The range is 4.2mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator is 0.636. The ratio of power to volume of the motor is the largest.

Table 4

The increase of the power of the motor will cause more heat during the operation of the motor. The reduction of the diameter of the grip will reduce the area of the heat dissipating air passage. The length of the lamination stack will lengthen the heat dissipating air passage. The above factors will cause the motor. The temperature rises, so it is necessary to optimize the air duct design to improve the heat dissipation efficiency of the motor.

The hand-held power tool 100 includes a tail cover 150 that is sleeved at the rear end of the body 11 and a guide 170 that is located between the body 11 and the tail cover 150. Wherein, the guiding member 170 and the tail cover 150 form an air inlet passage 190.

The rear end of the casing 110 is provided with a plurality of components 5, and the plurality of components 5 are specifically capacitors, switches and the like.

In this embodiment, the tail cover 150 is provided with an air inlet 1151. When the power tool 100 is in operation, the cooling air enters the heat radiating portion 115 from the air inlet port and flows through the motor 3, thereby reducing the heat of the motor 3, thereby achieving the purpose of heat dissipation.

In the present embodiment, the air inlet 1151 on the tail cover 150 includes a first air inlet 151 for allowing cooling air to enter the air inlet passage along the axial direction of the motor 3, and the cooling air enters the air inlet passage in a direction perpendicular to the axial direction of the motor 3. The second air inlet 153. Of course, it is also possible to provide the first air inlet 151 or the second air inlet 153 only on the tail cover 150.

The guide member 170 and the tail cover 150 enclose an air inlet passage 190. Specifically, the air inlet passage 190 extends axially along the motor 3 or at an angle to the axial direction of the motor 3. The air inlet passage 190 is in communication with the air inlet, and the air inlet passage 190 is in communication with the interior of the motor. The cooling air entering the air inlet flows along the air inlet passage 190 to the motor 3. Specifically, the direction indicated by the arrow in FIG. 8 is the flow direction of the cooling air.

The component 5 is located outside the air inlet passage 190. Preferably, the inlet passage 190 and the component 5 are located on different sides of the guide member 170. That is, the guiding member 170 separates the air inlet passage 190 and the component 5 on both sides of the guiding member 170, so that the cooling air entering the air inlet port no longer flows through the component 5, thereby preventing the cooling air from being blocked by the component 5, The eddy current is formed such that the cooling air entering the air inlet flows more toward the motor 130, improving the effective cooling air volume and cooling efficiency. Thereby, the heat dissipation effect of the electric tool 100 is enhanced, so that the motor and the casing avoid the phenomenon that the temperature rises due to poor heat dissipation effect, and the comfort of the holding portion of the casing is increased, which is convenient for the operator to operate.

In this embodiment, the guiding member 170 is disposed on the casing 110. Specifically, the guiding member 170 may be integrally formed with the body 11 or may be fixedly connected to the body 11, such as welding, screwing, snapping, and the like. If the guide member 170 is integrally formed with the body 11, the side wall of the body 11 can be used as a guide member, as long as the side wall of the housing can be enclosed with the tail cover 150 as the air inlet passage 190.

Of course, the guide member 170 can also be disposed on the tail cover 150. Similarly, the guide member 170 can also be integrally formed with the tail cover 150 or fixedly coupled to the tail cover 150, such as welding, screwing, snapping, and the like.

In this embodiment, the guiding member 170 is of a unitary structure. Of course, the guiding member 170 can also be formed by splicing a plurality of sub-guide members. The guide 170 can be in a regular or irregular shape.

In another embodiment, the guide member 170 is plate-shaped, which facilitates processing and allows the cooling air to circulate smoothly. Preferably, the guide member 170 is parallel to the axial direction of the motor 3 to make the cooling air flow more smoothly.

In another embodiment, the guide member 170 extends in the axial direction of the motor 3, and the guide member 170 has a curved surface in a section perpendicular to the axial direction of the motor 3. Preferably, the guide member 170 is fan-shaped in a section perpendicular to the axial direction of the motor 3.

It should be noted that the guiding member 170 is not limited to the above shape, and may have other regular or irregular shapes, as long as the air inlet passage 190 and the component 5 can be separated, so that the cooling air entering the air inlet directly flows to the motor 3 . Instead of flowing through the component 5.

In this embodiment, the guide member 170 is made of the same material as the body 11. Of course, the guide member 170 can also be made of materials of other materials. Preferably, the guide member 170 is made of a waterproof material to prevent the component 5 from degrading due to moisture.

In this embodiment, the power tool 100 is an angle grinder. Of course, the power tool 100 is not limited to the angle grinder, but may be other types of electric tools that have a motor and dissipate heat by cooling air.

In the above electric tool, the cooling air entering from the air inlet flows to the motor along the air inlet passage, and the component is located outside the air inlet passage, so that the cooling air entering the air inlet does not flow through the component, thereby avoiding The cooling air is blocked by the components to form a vortex, so that the cooling air entering the air inlet flows more toward the motor, which improves the effective cooling air volume and cooling efficiency.

Referring to FIG. 10 to FIG. 13 , in another embodiment of the present invention, a hand-held power tool is an oscillating machine, and the oscillating machine 600 includes a housing 610 , and a motor 3 received in the housing 610 . An internally extending output shaft 620, a working head (not shown) mounted on the extended end 621 of the output shaft 620, and a clamping assembly 623 for clamping the working head in the axial direction of the output shaft 620.

The structure of the motor 3 is the same as that of the motor 3 in the angle grinder 100 in the previous embodiment of the present invention. The specific structure is not described here. The difference lies only in the outer diameter of the motor 3 and the bare-metal idle speed (when not installed to the tool). The difference in the no-load speed) is described further in the following description.

Referring to FIG. 10, the housing 610 has a bottom portion opposite to the top portion and two side portions connecting the top portion and the bottom portion. The housing 610 is disposed at one end of the output shaft 30 at two ends. Two sets of air outlets 611 are disposed symmetrically disposed on the housing 610. Left and right sides.

In addition, the air intake opening 612 of the housing 610 is two sets, and the number of the air inlets 612 of the housing 610 is two sets symmetrically disposed on the left and right ends of the extended end of the housing 610. side.

The oscillating machine 600 includes a fan 650 housed in the housing 610. The fan 650 is disposed at a position near the air outlet 611 in a region between the motor 3 and the output shaft 620. The fan 650 is mounted on the armature shaft 33 by electricity. The pivot 33 is driven. When the motor 3 drives the armature shaft 33 to rotate, the fan 650 rotates at a high speed under the driving of the armature shaft 33, sucking external cold air from the air inlet 612 at the end of the housing 610, passing through the circuit board 670 and then passing through the entire board. The motor 3 then discharges the air carrying the heat through the air outlet 611 of the housing 610 through the fan 650.

The specific fan 650 can select a centrifugal fan, and is arranged to provide better discharge of hot air from the air outlet 611.

Further, referring to FIG. 11 and FIG. 12, a transmission mechanism is disposed between the armature shaft 33 and the output shaft 620. In this embodiment, the transmission mechanism is an eccentric transmission mechanism 640, and the eccentric transmission mechanism 640 is disposed in the housing 613, including the shift fork 641 and An eccentric component 642 is attached to the armature shaft 33. The eccentric assembly 642 includes an eccentric shaft 643 coupled to the armature shaft 33 and a drive wheel 644 mounted on the eccentric shaft 643. One end of the shift fork 641 is coupled to the top of the output shaft 620 and the other end is coupled to the drive wheel 644 of the eccentric assembly 642. The shift fork 641 includes a sleeve 645 that is sleeved on the output shaft 620 and a fork 646 that extends horizontally from the top end of the sleeve 645 toward the armature shaft 33. In the present embodiment, the drive wheel 644 is a ball bearing having a spherical outer surface that mates with the fork portion 646 of the shift fork 641. The eccentric shaft 643 is eccentrically coupled to the armature shaft 33, that is, the axis X3 of the eccentric shaft 643 does not coincide with the axis X2 of the armature shaft 33, and is radially offset by a certain pitch. The forks 646 of the fork 641 are wrapped around the sides of the drive wheel 644 and are in sliding contact with the outer surface of the drive wheel 644.

When the motor 3 drives the armature shaft 33 to rotate, the eccentric shaft 643 is eccentrically rotated relative to the axis X2 of the armature shaft 33 by the armature shaft 33, thereby driving the driving wheel 644 to rotate eccentrically with respect to the axis X2 of the armature shaft 33. Driven by the drive wheel 644, the shift fork 641 is swung relative to the axis Y of the output shaft 620 to further oscillate the output shaft 620 about its own axis Y. The output shaft 620 swings to drive the working head mounted thereon to swing the workpiece.

In this embodiment, the swing angle of the output shaft 620 is 5°. The swing frequency of the output shaft 620 is 18000-20000 rpm. By setting the swing angle of the output shaft 620 to 5°, the working efficiency of the working head is greatly improved, and when the working head is a saw blade, the discharge of debris is facilitated. It should be noted that, in the oscillating machine of the present invention, the swing angle of the output shaft 620 is not limited to 5°, and it may be set to a value greater than or less than 5° as needed. The swing frequency of the output shaft 620 is also not limited to 18000-20000 rpm, preferably greater than 10000 rpm.

Referring to Figure 11, in the present invention, the output shaft 620 is used to mount the working head. The output shaft 620 is mounted on the housing 610 and extends out of the housing 610, which facilitates mounting of the working head (not shown) on the output shaft 620. The motor 3 supplies power to the swinging machine 600, and the power of the motor 3 is transmitted to the output shaft 620 through the transmission mechanism 640, and the swinging machine 600 realizes the swinging operation. Work heads include straight saw blades, circular saw blades, triangular sanding discs and spade scrapers. When the operator installs different working heads on the output shaft 620, a variety of different operating functions, such as sawing, cutting, grinding, scraping, etc., can be realized to suit different work requirements and are convenient to use.

The housing 610 extends along the axis of the motor 3 and can be divided into a first region 614 that is remote from the output shaft 620 and a second region 615 that is adjacent to the output shaft 620. The first area 614 accommodates the motor 3 and includes a grip portion 630 formed on the outside of the motor 3 for the user to hold, and the power control switch 660 is disposed adjacent to the grip portion 630 or directly disposed on the grip portion 630; The second region 615 then houses the transmission mechanism 140.

The oscillating machine 600 of the present invention uses the motor 3 having an outer diameter of between 40 mm and 50 mm to power the oscillating machine 600, and the size of the housing 610 for the grip portion is reduced due to the reduction in the outer diameter of the motor 3. The reduction makes the overall size of the oscillating machine 600 of the present invention small, which is convenient for the operator to hold. At the same time, the oscillating machine 600 generates vibration during operation, but because of the small size of the whole machine, the grip is comfortable, even if there is vibration. Long-term grip will not make the operator uncomfortable.

As an implementation manner, by the limitation of the size of the outer diameter of the motor 3, the circumference of the grip portion of the housing 610 is in the range of 150 mm to 200 mm, so that the operator can hold the swinging machine 600, thereby facilitating the swinging machine. 600 operation to ensure processing efficiency.

However, generally reducing the outer diameter of the motor leads to a decrease in the output power of the motor. The present inventors have found through research that the output power of the motor can be affected by changing the outer diameter of the rotor and the size of the yoke when the outer diameter of the motor is determined. The specific analysis refers to Table 5 - Table 8.

Table 5 shows that the diameter of the stator is 46 mm, the axial length of the motor is 50 mm, and the bare metal idle speed of the motor 3 is 30,000 rpm (the idle speed when the motor is not mounted on the tool), at different stator yoke widths 331a (Refer to Fig. 4 for the specific structure), the change of motor power to volume ratio under the condition that the stator and rotor outer diameter ratios are changed. The values in Table 5 show that the stator yoke width 331a increases or the stator and rotor outer diameter ratios increase with the same motor volume and no-load speed, and the power of the motor exhibits an undulating change. For example, when the stator outer diameter ratio is 0.62, the ratio of power to volume reaches a maximum value of 5.54 when the stator yoke width 331a is 3.6 mm; when the stator yoke width 331a is 3.7 mm, the ratio of power to volume is in the stator When the outer diameter ratio is 0.62, the maximum value of 5.51 is reached. Table 5 is the experimental data when the stator diameter is 46mm. When the motor is larger and the other parameters are the same, the power-to-volume ratio of the motor will be larger.

table 5

The ratio of the power to the volume of the motor is a value that reflects the power output efficiency of the motor. Under the same volume, the larger the ratio, the greater the motor power. The motor power in Table 5 is the power value of the motor with a bare metal no-load speed of 30,000 rpm. The ratio of the stator and rotor outer diameters and the stator yoke width 331a all affect the ratio of motor power to volume. The larger the stator and rotor outer diameter ratio is, the larger the rotor size is, and the stator yoke width 331a is correspondingly reduced; vice versa. The larger the stator yoke width 331a, the smaller the stator slot and the rotor size, and vice versa. Reasonable design, rotor outer diameter ratio and yoke width can make the motor power reach a larger value.

In this embodiment, the ratio of motor power to volume is selected to be greater than 5 W/cm ³ , so that the hand-held swing machine 600 has a comfortable grip and more power under the same motor volume, especially the same stator diameter. Big.

Continuing with reference to Table 5, the same motor volume, the stator yoke width 331a increases or the stator and rotor outer diameter ratios increase, and the power of the motor 3 exhibits an undulating change. In one embodiment, the stator to rotor outer diameter ratio ranges from 0.6 to 0.7 and the outer diameter of the stator is no greater than 50 mm. Preferably, the outer diameter of the stator is 40-50 mm. In another alternative embodiment, the stator and rotor outer diameter ratios range from 0.6 to 0.65 and the yoke width ranges from 3.6 mm to 3.8 mm. The yoke width is excessively reduced to reduce the area of the slots, resulting in a reduction in stator winding. Within this size range, the power of the motor 3 fluctuates within a range close to the maximum value. The optimum motor has an outer diameter of 46 mm, a yoke width of 3.6 mm, and a ratio of stator to rotor inner and outer diameter of 0.62.

Table 6 shows that the stator has a diameter of 46 mm, the outer circumference of the grip is 198 mm, the axial length of the motor is 50 mm, and the bare motor idle speed is 30,000 rpm (the idle speed when the motor is not mounted on the tool) The ratio of the motor power to the outer circumference of the grip portion of the oscillating machine 600 under different conditions of different stator yoke widths 331a and stator and rotor outer diameter ratios. The values in Table 6 show the same motor volume, no-load speed and the outer circumference of the grip. The stator yoke width 331a increases or the stator and rotor outer diameter ratios increase, and the power of the motor exhibits an undulating change. For example, when the stator outer diameter ratio is 0.62, the ratio of power to outer circumference reaches a maximum value of 2.32 when the stator yoke width 331a is 3.6 mm; when the stator yoke width 331a is 3.7 mm, the ratio of power to volume is determined. When the rotor outer diameter ratio is 0.62, the maximum value of 2.16 is reached.

Table 6

The ratio of the power of the motor to the outer circumference of the grip is a value reflecting the power output efficiency of the motor. Under the same outer circumference, the larger the ratio, the larger the output power of the motor.

In one embodiment of the present invention, the ratio of the output power of the motor 3 to the peripheral circumference of the grip portion of the oscillating machine 600 is greater than 2.0 W/mm, where the output power refers to the maximum output power of the oscillating machine 600 input to the work object. The outer circumference of the grip portion of the oscillating machine 6001 is 150 mm to 200 mm. In order to have sufficient space inside the grip to accommodate the motor 3, the outer diameter of the stator is 40-50 mm.

In another alternative embodiment, the peripheral circumference of the grip portion of the oscillating machine 600 is set to 165 mm to 200 mm, and the outer diameter of the stator is 46-48 mm. The ratio of the output power of the motor 3 to the peripheral circumference of the grip portion of the oscillating machine 600 is greater than 2.1 W/mm.

In another alternative embodiment, the peripheral circumference of the grip portion of the oscillating machine 600 is set to 180 mm and the outer diameter of the stator is 46 mm. The ratio of the output power of the motor 3 to the peripheral circumference of the grip portion of the oscillating machine 600 is greater than 2.3 W/mm.

Generally, the motor 3 cannot be directly applied to the oscillating machine 600. Generally, the motor can be mounted on the oscillating machine by adding a speed stabilizer, and the idle speed of the whole machine is controlled at 20000 rpm, so that the corresponding output shaft 620 rotates at about 20,000 rpm. The specific how to use the speed stabilizer to control the rotational speed of the motor is a conventional means in the art, and will not be described here.

Table 7 shows that when the stator diameter is 46 mm and the axial length of the motor is 50 mm, the bare motor idle speed is 20000 rpm (the idle speed when the motor is not mounted on the tool), at different stator yoke widths 331a, The change of the motor power to volume ratio under the condition that the rotor and outer diameter ratios are changed. The values in Table 6 show the same motor volume, the stator yoke width 331a increases or the stator and rotor outer diameter ratios increase, and the power of the motor exhibits an undulating change. For example, when the fixed rotor outer diameter ratio is 0.62, the ratio of power to volume reaches a maximum value of 2.3 when the stator yoke width 331a is 3.6 mm; when the stator yoke width 331a is 3.7 mm, the power to volume ratio is at the stator and rotor. When the outer diameter ratio is 0.62, the maximum value of 2.15 is reached. Table 3 is the experimental data when the stator diameter is 46mm. When the motor is larger and the other parameters are the same, the power-to-volume ratio of the motor will be larger.

Further in combination with Table 5 above, it can be concluded that when the fixed rotor outer diameter ratio is 0.62, the ratio of power to volume reaches a maximum when the stator yoke width 331a is 3.6 mm; and the same stator yoke width 331a is 3.7 mm. The ratio of power to volume is maximized when the stator to rotor outer diameter ratio is 0.62. Therefore, it can be concluded that when the outer diameter of the stator is determined, regardless of the bare metal idle speed of the motor, the ratio of the inner and outer diameters of the stator to the stator is 0.62, and the power of the motor can be maximized when the yoke width of the stator is 3.6 mm.

Table 7

The ratio of the power to the volume of the motor is a value that reflects the power output efficiency of the motor. Under the same volume, the larger the ratio, the greater the motor power. The power of the motor in Table 6 is the power value when the bare motor has a no-load speed of 20000 rpm. The ratio of the stator and rotor outer diameters and the stator yoke width 331a all affect the ratio of motor power to volume. The larger the stator and rotor outer diameter ratio is, the larger the rotor size is, and the stator yoke width 331a is correspondingly reduced; vice versa. The larger the stator yoke width 331a, the smaller the stator slot and the rotor size, and vice versa. Reasonable design, rotor outer diameter ratio and yoke width can make the motor power reach a larger value.

In the present embodiment, the ratio of the motor power to the volume is selected to be greater than 2, so that the hand-held oscillating machine has a comfortable grip and a higher power under the same motor volume, especially the same stator diameter.

Continuing with reference to Table 7, for the same motor volume, the stator yoke width 331a is increased or the rotor outer diameter ratio is increased, and the power of the motor exhibits an undulating change. In one embodiment, the stator to rotor outer diameter ratio ranges from 0.6 to 0.7 and the outer diameter of the stator is no greater than 50 mm. Preferably, the outer diameter of the stator is 40-50 mm. In another alternative embodiment, the stator and rotor outer diameter ratios range from 0.6 to 0.65 and the yoke width ranges from 3.6 mm to 3.8 mm. The yoke width is excessively reduced to reduce the area of the slots, resulting in a reduction in stator winding. Within this size range, the power of the motor fluctuates within a range close to the maximum. At this time, the axial length of the motor, that is, the length of the stator along the axial direction of the armature shaft is set to be not less than 40 mm, and the setting range is 45 mm to 60 mm, preferably 55 mm.

Table 8 below shows that the stator has a diameter of 46 mm, the outer circumference of the grip is 198 mm, the axial length of the motor is 50 mm, and the bare motor idle speed is 20000 rpm (the idle speed when the motor is not mounted on the tool) The ratio of the motor power to the outer circumference of the grip portion of the oscillating machine 600 under different conditions of different stator yoke widths 331a and stator and rotor outer diameter ratios. The values in Table 6 show the same motor volume, no-load speed and the outer circumference of the grip. The stator yoke width 331a increases or the stator and rotor outer diameter ratios increase, and the power of the motor exhibits an undulating change. For example, when the fixed rotor outer diameter ratio is 0.62, the ratio of power to outer circumference reaches a maximum value of 0.81 when the stator yoke width 331a is 3.6 mm; when the stator yoke width 331a is 3.7 mm, the ratio of power to volume is determined. When the rotor outer diameter ratio is 0.62, the maximum value is 0.79.

Table 8

In one embodiment of the invention, the ratio of the output power of the motor 3 to the peripheral circumference of the grip portion of the oscillating machine 600 is greater than 0.8 W/mm, where the output power is the maximum output power that the oscillating machine 600 inputs to the work object. The outer circumference of the grip portion of the oscillating machine 600 is 150 mm to 200 mm. In order to have sufficient space inside the grip to accommodate the motor 3, the outer diameter of the stator is 40-50 mm.

In another alternative embodiment, the peripheral circumference of the grip portion of the oscillating machine 600 is set to 165 mm to 200 mm, and the outer diameter of the stator is 46-48 mm. The ratio of the output power of the motor 3 to the peripheral circumference of the grip portion of the oscillating machine 600 is greater than 0.85 W/mm.

In another alternative embodiment, the peripheral circumference of the grip portion of the oscillating machine 600 is set to 180 mm, and the outer diameter of the stator 121 is 46 mm. The ratio of the output power of the motor 3 to the peripheral circumference of the grip portion of the oscillating machine 600 is greater than 0.95 W/mm.

The bare metal idle speed of the above motor is 20,000 rpm, so it can be directly applied to the oscillating machine, so that the output shaft can meet the demand speed without any need for steady speed or other improvements.

Specifically, the number of air outlets can be increased, and a set of air outlets are additionally arranged at the bottom of the casing, so that the number of air outlets is three groups, and the discharge amount of hot air is increased, thereby improving the heat dissipation efficiency of the motor.

Of course, the number of air inlets can also be increased. A set of air inlets is additionally provided at the bottom of the casing, so that the number of air inlets is three, and the amount of air entering the cold air is increased, thereby improving the heat dissipation efficiency of the motor.

The technical features of the above embodiments may be arbitrarily combined. For the sake of brevity of description, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, It is considered to be the range described in this specification.

The above embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

A motor for use in a hand-held power tool, the motor comprising:

a stator, the stator being unitary;

a rotor coaxially sleeved in the stator;

An armature shaft fixedly coupled to the rotor;

a commutator fixedly connected to the armature shaft;

a brush electrically connected to the commutator;

The outer diameter of the stator is not more than 58 mm, the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.6 to 0.7, and the ratio of the output power of the motor to the volume is greater than 8.5 W/cm 3 .
The motor according to claim 1, wherein said stator outer diameter is not more than 50 mm, and said rotor outer diameter to said stator outer diameter ratio ranges from 0.6 to 0.65.
The electric machine according to claim 1, wherein said stator has a yoke width ranging from 3.6 mm to 4.2 mm.
The motor according to claim 1, wherein a length of said stator in the axial direction of said armature shaft is not less than 40 mm.
The motor according to claim 1, wherein said armature shaft has a diameter of not less than 7.5 mm.
The electric machine according to claim 5, wherein said armature shaft has a diameter ranging from 7.5 mm to 9 mm.
A motor for use in a hand-held power tool, the motor comprising:

a stator, the stator being unitary;

a rotor coaxially sleeved in the stator;

An armature shaft fixedly coupled to the rotor;

a commutator fixedly connected to the armature shaft;

a brush electrically connected to the commutator;

It is characterized in that the outer diameter of the stator is not more than 58 mm, the yoke width of the stator ranges from 3.5 mm to 4.2 mm, and the ratio of the outer diameter of the rotor to the outer diameter of the stator ranges from 0.618 to 0.65.
The motor according to claim 7, wherein said stator has an outer diameter of not more than 55 mm, said stator has a yoke width ranging from 4.1 mm to 4.3 mm, and said rotor outer diameter and said stator outer diameter ratio range It is from 0.618 to 0.636.
The motor according to claim 8, wherein said stator has an outer diameter of 55 mm, said stator has a yoke width of 4.2 mm, and said rotor outer diameter to said stator outer diameter ratio ranges from 0.636.
The motor according to claim 7, wherein said stator has an outer diameter of not more than 50 mm, said stator has a yoke width ranging from 3.8 mm to 4.2 mm, and said rotor outer diameter and said stator outer diameter ratio range It is 0.62 to 0.64.
The motor according to claim 9, wherein said stator has an outer diameter of 50 mm, said stator has a yoke width of 3.8 mm, and said rotor outer diameter to said stator outer diameter ratio ranges from 0.62.
The motor according to claim 7, wherein said stator has an outer diameter of not more than 46 mm, said stator has a yoke width ranging from 3.5 mm to 3.7 mm, and said rotor outer diameter and said stator outer diameter ratio range It is from 0.62 to 0.65.
The motor according to claim 11, wherein said stator has an outer diameter of 46 mm, said stator has a yoke width of 3.6 mm, and said rotor outer diameter to said stator outer diameter ratio ranges from 0.62.
A hand-held power tool having the motor of any of the preceding claims 1-13, further comprising:

a casing, the casing includes a fuselage and a head casing, and the fuselage is fixedly coupled to the head casing;

a transmission mechanism that transmits torque of the armature shaft to the output shaft;

The utility model is characterized in that the body has a grip portion, the grip portion at least accommodates the stator, a periphery of the grip portion is used for gripping, and a peripheral circumference of the grip portion ranges from 150 mm to 185 mm. The ratio of the output power of the motor to the peripheral circumference of the grip portion is greater than 5.1 W/mm.
The hand-held power tool according to claim 14, wherein a peripheral circumference of the grip portion ranges from 165 mm to 182 mm, and an outer diameter of the stator is no more than 50 mm.
The hand-held power tool according to claim 15, wherein a ratio of an output power of the motor to a peripheral circumference of the grip portion is greater than 5.2 W/mm.
The hand-held power tool according to claim 16, wherein a ratio of an output power of the motor to a peripheral circumference of the grip portion is greater than 5.35 W/mm.
The hand-held power tool according to claim 15, wherein a peripheral circumference of the grip portion ranges from 165 mm to 170 mm, an outer diameter of the stator is no more than 46 mm, and the stator is along the armature shaft. The axial length is not less than 50 mm.
The hand-held power tool according to claim 18, wherein a ratio of an output power of the motor to a peripheral circumference of the grip portion is greater than 5.15 W/mm.
The hand-held power tool according to claim 14, wherein the armature shaft has a diameter of not less than 7.5 mm.
A hand-held power tool according to claim 20, wherein said armature shaft has a diameter ranging from 7.5 mm to 9 mm.
The hand-held power tool according to claim 14, wherein the body includes a heat dissipating portion, and the grip portion is located between the head case and the heat dissipating portion, and a cross section of the grip portion The area is smaller than the cross-sectional area of the heat dissipating portion.
The hand-held power tool according to claim 22, wherein the material of the body is plastic, the tensile strength is greater than 200 MPa, and the moisture absorption rate is less than 2%.
The hand-held power tool according to claim 22, wherein the heat radiating portion has an air inlet, and the air inlet extends from one end to the other end of the heat radiating portion along an axial direction of the heat radiating portion.
The hand-held power tool according to claim 24, wherein the head casing has an air outlet, and the ratio of the area of the air inlet to the area of the air outlet is not less than 1.
The hand-held power tool according to claim 23, 24 or 25, wherein the casing comprises a connecting portion, and the holding portion and the heat radiating portion are connected by the connecting portion.
The hand-held power tool according to claim 14, wherein the hand-held power tool further comprises a component disposed at a tail end of the body, a tail cover sleeved at a tail end of the body, and a guiding member between the fuselage and the tail cover, the tail cover is provided with an air inlet, the guiding member and the tail cover enclosing an air inlet passage, the air inlet passage and the air inlet and the motor In communication, cooling air entering the air inlet flows along the air inlet passage to the motor, and the component is located outside the air inlet passage.
A hand-held power tool according to claim 27, wherein said air inlet passage and said component are located on different sides of said guide member.
The hand-held power tool according to claim 27, wherein the guide member is provided on the body.
The hand-held power tool according to claim 27, wherein the guide member is integrally formed with the casing, or the guide member is fixedly coupled to the casing.
The hand-held power tool according to claim 27, wherein said guide member is provided on said tail cover.
The hand-held power tool according to claim 27, wherein the guide member has a plate shape.
A hand-held power tool according to claim 32, wherein said guide member is parallel to an axial direction of said motor.
A hand-held power tool according to claim 27, wherein said guide member extends in the axial direction of said motor, and said guide member has a curved surface in a section perpendicular to an axial direction of said motor.
A hand-held power tool according to claim 27, wherein said air inlet passage extends in the axial direction of said motor.
A hand-held power tool according to claim 27, wherein the air inlet on the tail cover includes a first air inlet for allowing cooling air to enter the air inlet passage along the motor axis, and cooling air The second air inlet of the air inlet passage is entered in a direction perpendicular to the axial direction of the motor.
A hand-held power tool, comprising:

case;

An output shaft for mounting a working head, the output shaft being mounted in the housing and extending out of the housing;

a transmission mechanism installed in the housing, and the transmission mechanism is coupled to the output shaft; and

a motor mounted in the housing, comprising: a stator, the stator being monolithic; a rotor coaxially sleeved in the stator; an armature shaft fixedly coupled to the rotor; the armature a shaft coupled to the transmission mechanism, the transmission mechanism converting a rotational motion of the armature shaft into a reciprocating motion of the output shaft about its own axis line;

Wherein, the outer diameter of the motor ranges from 40 mm to 50 mm, the bare metal idle speed of the motor is greater than 20000 rpm, and the ratio of the output power of the motor to the volume is greater than 2 W/cm 3 .
The hand-held power tool according to claim 37, wherein the housing is provided with a grip portion, and the grip portion has an outer circumference of 150 mm to 200 mm.
The hand-held power tool according to claim 38, wherein a ratio of an output power of said motor to a peripheral circumference of said grip portion is greater than 0.8 W/mm.
The hand-held power tool according to claim 39, wherein a ratio of an output power of said motor to a peripheral circumference of said grip portion is greater than 0.95 W/mm.
The hand-held power tool according to claim 37, wherein the bare metal no-load speed of the motor is greater than 30,000 rpm, and the motor output power to volume ratio is greater than 5.5 W/cm3.
The hand-held power tool according to claim 41, wherein the housing is provided with a grip portion, and the outer circumference of the grip portion is 150 mm - 200 mm, and the output power of the motor and the grip portion are The peripheral perimeter ratio is greater than 2.0 W/mm.
The hand-held power tool according to claim 37, wherein said rotor outer diameter and said stator outer diameter ratio are in the range of 0.60 to 0.70, and said stator yoke width is 3.5 to 4.0 mm.
The hand-held power tool according to claim 43, wherein a ratio of an outer diameter of the rotor to an outer diameter of the stator ranges from 0.65 to 0.70, and a width of the stator yoke is 3.5 to 3.8 mm.
The hand-held power tool according to claim 37, wherein said stator has an outer diameter of 46 mm, said yoke width is 3.6 mm, and said rotor outer diameter to said stator outer diameter ratio is 0.62.
A hand-held power tool according to claim 37, wherein said motor has an axial length ranging from 45 mm to 60 mm.