CN218639511U

CN218639511U - Impact tool and electric tool

Info

Publication number: CN218639511U
Application number: CN202220682489.5U
Authority: CN
Inventors: 徐瑞; 王小勇; 吴迪
Original assignee: Nanjing Chervon Industry Co Ltd
Current assignee: Nanjing Chervon Industry Co Ltd
Priority date: 2022-03-25
Filing date: 2022-03-25
Publication date: 2023-03-17
Anticipated expiration: 2032-03-25

Abstract

The utility model discloses an impact tool and electric tool, include: a housing; a motor accommodated in the housing; the motor includes: a rotor and a driving shaft formed or connected to the rotor and rotating with a first axis as a shaft; the rotor includes: a rotor main body and a permanent magnet disposed in the rotor main body; an impact assembly for providing an impact force; the transmission assembly is used for transmitting the rotation of the motor to the impact assembly; the transmission assembly includes: a sun gear connected to or formed at a front end of the driving shaft; also comprises the following steps; a holder that holds the permanent magnet in the rotor main body; the retainer is disposed around the drive shaft and is held by the sun gear and the rotor body. By adopting the scheme, the impact tool with simple structure, compact volume and short overall length can be provided.

Description

Impact tool and electric tool

Technical Field

The utility model relates to an electric tool, concretely relates to impact tool and electric tool.

Background

Impact tools are capable of outputting rotational motion with a certain impact frequency, including but not limited to impact wrenches, impact screwdrivers. For example, in the case of impact wrenches for tightening bolts, nuts, impact screwdrivers typically loosen or tighten screws, etc. Impact tool is in order to realize having certain impact frequency's rotary motion, therefore need still include the impact assembly who carries out periodic impact to output assembly including the output piece that is used for exporting the revolving force, then can make whole impact tool's volume great like this, in some narrow and small operating modes, the unable work that gets into of the great impact tool of volume leads to the installation or dismantles efficiency reduction.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an impact tool and electric tool to it is great to solve impact tool's among the prior art volume, leads to the problem of inefficiency when the installation of corner position and narrow and small operating mode or dismantlement.

In order to achieve the above object, the utility model adopts the following technical scheme:

an impact tool, comprising: a housing; a motor accommodated in the housing; the motor includes: a rotor and a driving shaft formed or connected to the rotor and rotating with a first axis as a shaft; the rotor includes: a rotor body and a permanent magnet disposed in the rotor body; an impact assembly for providing an impact force; the transmission assembly is used for transmitting the rotation of the motor to the impact assembly; the transmission assembly includes: a sun gear connected to or formed at a front end of the driving shaft; also includes; a holder that holds the permanent magnet in the rotor main body; the retainer is disposed around the drive shaft and is held by the sun gear and the rotor body.

In some embodiments, a plurality of permanent magnets are disposed in the rotor, a retainer is sleeved outside the drive shaft, and the retainer engages each of the plurality of permanent magnets.

In some embodiments, the retainer is a unitary structure.

In some embodiments, the holder has a front-to-rear dimension in the first axial direction of 0.3mm or more and 1mm or less.

In some embodiments, the electric machine further comprises a stator, the rotor being disposed coaxially with and within the stator.

In some embodiments, a motor front bearing for supporting a front end portion of the drive shaft; the transmission assembly further includes: a gearbox housing within which the impact assembly is at least partially disposed; the sun gear is at least partially disposed within the gearbox housing; the front bearing of the motor is sleeved on the sun gear; the motor front bearing is arranged in the gearbox shell.

In some embodiments, the gearbox housing at least partially overlaps the electric machine in the first axial direction; the motor front bearing at least partially overlaps the motor in the first axial direction.

In some embodiments, the rear end of the sun gear extends along a direction perpendicular to the first axis and is provided with a second protruding portion, and the second protruding portion is jointed with the rear end surface of the front bearing of the motor.

In some embodiments, the gearbox housing extends towards the inside of the gearbox housing in a direction perpendicular to the first axis and is provided with a first boss, and the first boss is engaged with the front end surface of the motor front bearing.

A power tool, comprising: a housing; a motor accommodated in the housing; the motor includes: a rotor and a driving shaft forming or connecting the rotor and rotating with a first axis as a shaft; the rotor includes: a rotor main body and a permanent magnet disposed in the rotor main body; a power output mechanism driven by the drive shaft to output power; the transmission assembly is used for transmitting the rotation of the motor to the power output mechanism; the transmission assembly includes: a sun gear connected to or formed at a front end of the driving shaft; also comprises the following steps; a holder that holds the permanent magnet in the rotor body; the retainer is disposed around the drive shaft and is held by the sun gear and the rotor body.

The utility model provides an impact tool and electric tool uses sun gear and rotor main part cooperation centre gripping keeper, and then has cancelled the rotor front end plate, and the assembly is simple, and product cost is low. Meanwhile, the gear box shell and the front bearing of the motor are overlapped with the projection of the motor on a plane parallel to the first axial direction, so that the length of the impact tool in the first axial direction is shortened while the internal structure of the impact tool is simplified. And because the gear box shell is overlapped with the motor, namely the gear box shell is partially accommodated in the through hole of the motor stator, and the sun gear is also partially accommodated in the through hole of the motor stator, the internal structure of the impact tool can be further simplified, and the length of the impact tool in the first axial direction can be shortened.

Drawings

FIG. 1 is a block diagram of a first embodiment of the present application;

FIG. 2 is another perspective of FIG. 1;

FIG. 3 is a partial cross-sectional view of the first embodiment of FIG. 1;

FIG. 4 is a partially exploded view of the first embodiment of FIG. 3, with the outer housing and hammer case removed;

FIG. 5 is another perspective of FIG. 4;

FIG. 6 is a partially exploded view of the motor of the first embodiment of FIG. 5 to illustrate the fan of the motor;

FIG. 7 is a view showing the construction of a fan of the first embodiment shown in FIG. 1;

FIG. 8 is a fragmentary view of FIG. 3 with the housing removed;

FIG. 9 is a partially exploded view of the motor and sun gear of the first embodiment of FIG. 4;

FIG. 10 is a cross-sectional view of FIG. 9 assembled;

FIG. 11 is a fragmentary view of FIG. 3 illustrating the drive shaft, motor front bearing, transmission assembly, spindle and spindle bearings of the impact tool;

FIG. 12 is a second schematic position diagram of the impact block of the first embodiment of FIG. 1;

FIG. 13a is a plan view from another perspective of FIG. 1;

FIG. 13b isbase:Sub>A cross-sectional view A-A of FIG. 13base:Sub>A;

FIG. 14 is a first schematic position of the impact block of the first embodiment of FIG. 1;

FIG. 15a is a plan view from another perspective of FIG. 14;

FIG. 15B is a cross-sectional view B-B of FIG. 15 a;

FIG. 16 is a partial perspective view of the spindle and impact block of the first embodiment of the impact block of FIG. 1 in a second position to illustrate the first ball groove, the second ball groove, and the ball;

FIG. 17 is a partial cross-sectional view of the exploded view of FIG. 16, a one-sided ball seated in the first ball groove and a one-sided ball seated in the second ball groove;

FIG. 18 is a structural view of the impact block of the first embodiment in FIG. 1;

FIG. 19 is a sectional view of a portion of a second embodiment of the present application;

FIG. 20 is an exploded view of a portion of the second embodiment of FIG. 19;

FIG. 21 is another perspective of FIG. 20;

FIG. 22 is an exploded view of a portion of the motor and gear assembly of the second embodiment of FIG. 19;

fig. 23 is a partial cross-sectional view of a third embodiment of the present application.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

For the sake of clarity of the technical solution of the present invention, an upper side, a lower side, a front side and a rear side as shown in fig. 1 are also defined.

Fig. 1 to 18 show a power tool according to a first embodiment of the present application, which is an impact tool 1, and the impact tool 1 is specifically an impact screwdriver for screwing a screw, and may be an impact wrench for screwing a bolt or a nut.

The impact tool 1 comprises a motor 11, a transmission assembly 12, an impact assembly 13, a power take-off assembly 14 and a housing 15. Wherein, the motor 11, the transmission component 12, the impact component 13 and the power output component 14 are sequentially arranged in the shell 15 along the front-back direction.

The motor 11 includes or is coupled to a drive shaft 111 rotatable relative to the housing 15 about the first axis 101, the drive shaft 111 for outputting power. The driving shaft 111 in this embodiment is formed on the rotor 114 of the motor 11, and in other embodiments, the driving shaft 111 may be another rotating shaft in transmission connection with the rotor 114 of the motor 11.

The housing 15 also forms or is connected to a grip 151 for user operation. The holding portion 151 and the housing 15 form a T-shaped or L-shaped structure, which is convenient for a user to hold and operate. The power supply device 16 is connected to one end of the grip 151. The power supply device 16 is detachably connected to the housing 15. Of course, the power supply device 16 may also be provided as mains. In the present embodiment, the power supply device 16 is a battery pack. The hammer case 153 is attached to the forward end of the housing 15 and the impact assembly 13 is at least partially disposed within the hammer case 153.

The power output assembly 14 includes an output shaft 141, and a receiving portion 1412 is disposed at a front end of the output shaft 141 and is capable of receiving corresponding working heads, such as a screwdriver, a drill, a wrench, etc., when different functions are implemented.

It will be appreciated that in other alternative embodiments, the power take-off assembly may also be a grass cord for a grass trimmer, a blade for a power tool for abrading, a sandpaper-like working element, a grass cutting blade, and other types of actuators that are driven by the driving force output from a motor to perform a work function.

As shown in fig. 1 to 8, when the motor 11 is operated at a high speed, a large amount of heat is generated, and a current flows through the stator winding, which causes heat generation of the coil, and the heat is accumulated in the case 15, and the excessive heat causes a series of problems, for example, a time for which a high power output can be maintained becomes short, and thus, a practical demand of the impact tool cannot be satisfied. In order to improve the heat dissipation efficiency of the motor 11 and to effectively dissipate heat, a fan 117 is installed on the motor 11. One end of the motor 11 is used for outputting driving force and is connected with a power output assembly 14 through a transmission assembly 12 and an impact assembly 13; the other end is connected to a fan 117. In the present embodiment, a fan 117 is mounted to the rear end of the motor 11. In other alternative embodiments, the fan 117 may be provided at other positions of the motor 11 depending on the mounting position of the motor in the housing and the layout of the driving force output relationship in the impact tool. The housing 15 is provided with a heat dissipating hole 154 as an air outlet, which communicates the inside and the outside of the housing 15, at a position corresponding to the fan 117. The air inlet is arranged at the front end of the motor 11. Fan 117 is driven by drive shaft 111 to rotate about a second axis. In this embodiment, the fan 117 is directly mounted to the drive shaft 111 via a central aperture 1173, and the second axis is coincident with the first axis 101. In other embodiments, the driving shaft may be connected to the fan 117 through other mechanisms with a transmission ratio, and the specific fan 117 is not limited to be directly driven or indirectly driven by a motor, and the position relationship between the second axis and the first axis is different according to the transmission manner of the fan 117 and the driving shaft, including but not limited to being mutually angled or parallel; the driving shaft 111 only needs to be capable of driving the fan 117 to rotate.

The impact tool 1 further includes a motor rear bearing 113, and the motor rear bearing 113 supports the rear end of the drive shaft 111. The motor rear bearing 113 is detachably installed in the housing 15, an outer race of the motor rear bearing 113 is engaged with a rear end of the housing 15, an inner race of the motor rear bearing 113 abuts against an outer circumferential surface of the driving shaft 111, and in this embodiment, an inner sidewall 157 of the rear end of the housing is provided with a bearing installation groove 155, and the motor rear bearing 113 is detachably installed in the bearing installation groove 155.

The fan 117 includes fan blades 1171 and a fan base 1172 on which the fan blades 1171 are mounted. Wherein the central aperture 1173 of the fan 117 is disposed on the fan base 1172. In this embodiment, the central aperture 1173 of the fan 117 is disposed on the geometric center of the fan base 1172. Fan blades 1171 are disposed on one side of fan base 1172 about the circumference of fan base 1172, specifically, fan blades 1171 are at least partially disposed on the front face of fan base 1172, and the rear side of fan base 1172 faces motor rear bearing 113. Fan blades 1171 each rotate about drive shaft 111 about first axis 101. The motor rear bearing 113 at least partially overlaps the fan 117 in the direction of the first axis 101. That is, there is at least one line perpendicular to the first axis 101 that passes through both the motor rear bearing 113 and the fan 117. Specifically, the fan base 1172 defines a recess 1174 surrounding the central aperture 1173 of the fan 117, and the motor rear bearing 113 is at least partially disposed within the recess 1174. The fan 117 at least partially overlaps the motor 11 in the direction of the first axis 101. This allows the impact tool to be more compact in the direction of the first axis 101, reducing the length of the impact tool in the forward and rearward direction, specifically, the outer side wall 156 at the rear end of the housing to the front end of the impact tool, which can be reduced by at least 6mm depending on the size of the rear bearing of the existing motor.

As shown in fig. 7, in the present embodiment, the fan base 1172 covers a portion of the fan blades 1171 in a direction perpendicular to the first axis 101. Specifically, in the longitudinal direction of fan blades 1171, fan base 1172 covers fan blades 1171 halfway; all of the blades 1171 form a circular or circular-like outer contour, and the perimeter-forming edge contour of the fan base 1172 lies within the blade-forming outer contour. Wherein, in the direction along the first axis 101, the smallest circle which includes the outer contour of the fan base plate 1172 is drawn in a second projection plane which is perpendicular to the first axis 101 by taking the first axis 101 as a central point, and the radius of the smallest circle is R1; drawing a minimum circle which includes the outer contour of the fan blade 1171 in a second projection plane which is vertical to the first axis 101 by taking the first axis 101 as a central point, wherein the radius of the minimum circle is R2; wherein R1 is less than R2. In this embodiment, the rear side edges of the fan blades 1171 of the fan 117 are flush or substantially flush with the rear end face of the fan base 1172. In this embodiment, the fan 117 structure in which fan base 1172 partially covers fan blades 1171 and fan base 1172 is fitted into fan blades 1171 is adopted, so that the front-rear dimension of fan base 1172 in the first axial direction is ensured, and the front-rear plate thickness dimension of fan base 1172 in the first axial direction is reduced. In this embodiment, the front-back dimension of the fan blade 1171 along the first axial direction is the height of the fan blade 1171, and preferably, the height of the fan blade 1171 is 2.5mm. The fan 117 is shorter in length in the front-to-back direction along the first axis, which can be shortened by at least 1.2mm in the front-to-back direction along the first axis according to existing fan base 1172 size specifications.

In this embodiment, fan 117 is a centrifugal fan, and more specifically, is a centrifugal fan having a fan base 1172 partially covering fan blades 1171. It has been found that when the fan bottom plate 1172 is used to partially cover the fan blades 1171 and the fan bottom plate 1172 is embedded in the fan structure of the fan blades 1171, the air volume generated by the rotation of the centrifugal fan will cause a certain loss of the air flow in the motor 11, so that the heat dissipation performance of the motor 11 is reduced. By increasing the diameter of the fan, increasing the height of the fan blades and the like, although the air quantity of the fan can be increased to improve the heat dissipation performance, the overall size of the impact tool is increased, and the impact tool does not meet the requirement of product miniaturization. Through research and experiments, the applicant finds that the auxiliary wind shielding surface 118 is arranged on the side of the fan bottom plate 1172 far away from the fan blades 1171, and the air flow in the motor generated by the rotation of the centrifugal fan can be changed by adjusting the gap distance L2 between the fan 117 and the auxiliary wind shielding surface 118, so that the purpose of improving the heat dissipation performance of the motor is achieved. The heat dissipation holes 154 are formed on a side of the plane of the auxiliary wind shielding surface 118 close to the fan. In the present embodiment, the heat radiation holes 154 are opened in the front side of the auxiliary wind shielding surface 118.

In the present embodiment, in order to meet the demand for miniaturization of the product, the auxiliary wind shielding surface 118 is provided on the inner sidewall 157 at the rear end of the housing, the auxiliary wind shielding surface 118 is perpendicular to the first axis 101, and the heat radiation hole 154 is opened in front of the inner sidewall 157 at the rear end of the housing. A vertical distance L2 between the auxiliary wind shielding surface 118 and an end surface of the fan 117 facing the housing is set to 0.9mm or more and 1.2mm or less. In the present embodiment, L2 is a vertical distance between the rear end surface of the fan 117 and the inner sidewall 157 of the rear end of the housing.

Specifically, with reference to table 1, sample number 1 is the air gap flow when the fan of the related art is used, and the air gap flow of the motor here is the air flow between the rotor 114 and the stator 115 of the motor. Specifically, the fan in the prior art is a centrifugal fan in which a fan bottom plate completely covers fan blades, the radius R2=22.4mm of the fan blades, the fan bottom plate completely covers the fan blades, the fan bottom plate is not embedded with the fan blades, that is, the fan blades are completely arranged on the front side of the fan bottom plate, and the height of the fan blades is 2.5mm. Because the fan bottom plate completely covers the fan blades, the fan in the prior art has no auxiliary wind shielding surface. Sample numbers 2-9 are air gap flow rates when the fan floor partially covers the fan blades, where the height of fan blades 1171 is 2.5mm, r2=22.4mm, and r1=17.5mm. According to the manufacturing controllable tolerance, the gaps between the rear end face of the fan 117 and the auxiliary wind shielding face 118 are respectively adjusted to be 0.6mm, 0.8mm, 1.0mm, 1.1mm, 1.2mm, 1.5mm, 1.8mm and 2.0mm, the rotating speed of the motor and the rotating speed of the fan 117 driven by the motor are the same, and the air gap flow of the motor is recorded in the same time. Table 1 was obtained.

Table 1:

when L2 is 0.6mm to 1.0mm, the air gap flow increases correspondingly as the gap distance increases. When L2 is 1.0 to 1.1mm, the air gap flow increases with increasing gap distance. When L2 is 1.1mm to 1.2mm, the air gap flow begins to decrease as L2 increases. When L2 is 1.2 to 2.0mm, the air gap flow continues to decrease as the gap distance increases. It can be seen that the gap between the auxiliary wind shielding surface 118 and the rear end surface of the fan 117 is not a pure positive or negative correlation with the air gap flow, and needs to be adjusted to a suitable distance range to ensure the heat dissipation efficiency of the motor. In the prior art, however, the inner side wall of the housing functions to support the fixing or receiving member when it is disposed in the impact tool or the power tool. It is also provided with a clearance from the rear end face of the fan 117, the purpose of this clearance being to comply with design or assembly tolerance levels and the like, so that the inner side wall or other plane of the housing at this time is not to be understood as nor belonging to the auxiliary wind shielding face.

In the present application, the applicant has found through research that, when the distance range is greater than or equal to 0.9mm and less than or equal to 1.2mm, the setting plane can ensure that the air volume of the fan product in the motor heat dissipation still meets the motor heat dissipation requirement under the condition that the length dimension of the fan 117 in the front-back direction is shorter than that of the existing fan 117, and at this time, the plane set according to the design requirement in the distance range is an auxiliary wind shielding surface. At this time, when the length dimension of the fan 117 in the front-rear direction is shortened by 40% compared to the conventional fan 117, the air volume of the fan 117 of this embodiment can still reach 85% of the air volume of the conventional fan, and when L2=1.1mm, the air volume of the fan 117 of this embodiment can still reach 86% of the air volume of the conventional fan.

On the premise of not changing the size of the fan 117 and not affecting the miniaturization of the impact tool 1, through research and experiments, the applicant finds that the effect of ensuring the heat dissipation air volume can be achieved by adjusting the length of the fan bottom plate 1172 covering the fan blades 1171. As shown in the combination table 2; the sample number 1 is an air gap flow rate when the fan in the prior art is used, specifically, the fan in the prior art is a centrifugal fan in which a fan bottom plate completely covers fan blades, a radius R2=22.4mm of the fan blades, the fan bottom plate completely covers the fan blades, the fan bottom plate is not embedded with the fan blades, that is, the fan blades are completely arranged on the front side of the fan bottom plate, and a height of the fan blades is 2.5mm. Sample No. 2-10 is the air gap flow when the fan bottom plate partially covers the fan blades, the fan bottom plate is embedded in the fan blades and the rear side edges of the fan blades 1171 are flush with the rear end face of the fan bottom plate 1172, specifically, R2=22.4mm, l2=1.1mm, and the height of the fan blades is 2.5mm; using fan base 1172 radius R1 of 11.5mm, 12.5mm, 13.5mm, 14.5mm, 15.5mm, 16.5mm, 17.5mm, 18.5mm and 19.5mm, respectively; the motor speed and the motor-driven fan 117 speed are the same and the air gap flow of the motor is recorded during the same time.

Table 2:

it can be seen that for a dimension of R1 of 11.5mm to 12.5mm, the air gap flow decreases with increasing dimension of R1; when the size of R1 is 12.5mm to 14.5mm, the air gap flow rate increases along with the increase of the size of R1; with R1 sizes of 14.5 to 19.5mm, the air gap flow decreases again as R1 size increases. It can be seen that the size of the radius R1 of the fan and the air gap flow are not purely in a positive correlation or a negative correlation, and the heat dissipation efficiency of the motor can be ensured only by adjusting the radius R1 to a suitable distance range, and meanwhile, in order to ensure the structural strength of the fan 117, when the size of the radius R1 of the fan is greater than or equal to 11.5mm and less than or equal to 17.5mm, the air gap flow of the motor is greater than or equal to 85% of the air gap flow of the motor in the prior art, and the actual requirements of the impact tool can be met. That is, the fan radius R1 is related to the fan base plate by R1 < R2, and 4; preferably, R1: R2=5, where L2=1.1mm, the air gap flow is 88% of the prior art air gap flow.

It is understood that the specific structures, positional relationships, connection manners, and the like of the fan 117, the auxiliary wind shielding surface 118, and the motor 11 in the present embodiment can be applied to other electric tools, for example, hand-held electric tools such as electric drills, impact drills, electric screw drivers, electric tools for grinding (sanders, flat sanders, angle grinders), reciprocating saws, and multifunction tools; grass trimmers, lawn mowers, pruners, and electric saws. In the application condition that it requires miniaturization products, the specific structures, the positional relationship and the connection mode of the fan 117, the auxiliary wind shielding surface 118 and the motor 11 in this embodiment can be changed, and such changes are suggested by this application.

And an impact assembly 13 for providing an impact force. The impact assembly 13 includes a main shaft 131, an impact block 134 disposed around the main shaft 131, and an anvil 135 disposed at a front end of the impact block 134. The anvil 135 includes an anvil 1411 and an output shaft 141; the impact block 134 is driven by the main shaft 131, the anvil 1411 is engaged with and struck by the impact block 134, and the anvil 1411 drives the output shaft 141 to rotate. The impact block 134 comprises an impact block main body 134a and a pair of first end teeth 1344 radially and symmetrically arranged on the front end face 134b of the impact block main body 134a in a protruding manner; a pair of second end teeth 1351 is radially symmetrically and convexly provided on the rear end surface of the anvil 1411 opposite to the impact block 134. The output shaft 141 extends out of the hammer case 153; the output shaft 141 is connected to the anvil 1411, it being understood that the anvil 1411 and the output shaft 141 may be integrally formed or separate pieces that are separately formed.

As shown in fig. 1 to 11, the rotor 114 of the motor 11 is coaxially sleeved in the stator 115, that is, the motor 11 is an inner rotor motor. The rotor 114 further includes a rotor body 1141 located inside the stator 115 and a plurality of permanent magnets 116. The permanent magnets 116 are received in corresponding magnet receiving grooves 1142 formed on the rotor main body 1141. The magnet receiving groove 1142 substantially conforms to the contour of the permanent magnet 116 and extends substantially in length in a direction along the first axis 101.

The stator 115 includes a stator core 1151 and a stator winding 1152 wound around the stator core 1151, the stator core 1151 is provided with a through hole 1153, and the rotor 114 is located inside the stator core 1151. When energized, the stator windings 1152 generate a magnetic field that interacts with the permanent magnets 116 in the rotor 114 to cause the rotor 114 to rotate relative to the stator 115.

As shown in fig. 8, the driving shaft 111 passes through the rotor 114, and both ends of the driving shaft 111 are disposed beyond the end face of the rotor 114, and a motor front bearing 112 is disposed on a portion of the front end of the driving shaft 111 beyond the front end face of the rotor 114 for supporting. The rear end of the driving shaft 111 is partially connected to the fan 117 beyond the rear end of the rotor 114 and supported by a motor rear bearing 113, and the motor rear bearing 113 is positioned by a housing structure. Wherein the motor front bearing 112 at least partially overlaps the motor 11 in the direction of the first axis 101. In the present embodiment, the motor front bearing 112 at least partially overlaps the stator 115 in the first axis 101 direction. That is, there is at least one line perpendicular to the first axis 101, which line passes through both the motor front bearing 112 and the stator 115, the motor front bearing 112 being at least partially located in a through hole 1153 in the stator core 1151.

As shown in fig. 8 to 11, the drive shaft 111 is connected to the transmission assembly at a portion of the front end of the drive shaft 111 beyond the front end surface of the rotor 114. The transmission assembly includes: a gearbox housing 123, a sun gear 121 disposed at least partially within the gearbox housing 123, and a planetary gear set 122 rotating in meshing engagement with the sun gear 121. In the present embodiment, the gear housing 123 is formed with a first accommodating space 1232a at the front end of the gear housing 123 and a second accommodating space 1232b at the rear end of the gear housing 123, respectively. Wherein a portion of the main shaft 131 is disposed in the first accommodating space 1232 a. The motor front bearing 112 is disposed in the second accommodation space 1232b. Specifically, the outer ring of the motor front bearing 112 abuts against the inner wall of the second accommodating space 1232b, and the inner ring of the motor front bearing 112 abuts against the drive shaft 111, thereby realizing circumferential position limitation of the drive shaft 111. A first protrusion 1232c is provided in the second accommodating space 1232b to extend in a direction perpendicular to the first axis 101, and the first protrusion 1232c extends inward in the circumferential direction of the second accommodating space 1232b. The first protruding portion 1232c may continuously form a complete flange around the circumference of the second accommodating space 1232b, or may be provided in plurality at intervals along the circumference of the second accommodating space 1232b. The rear end surface of the first protrusion 1232c abuts against the front end surface 1121 of the motor front bearing 112. The gearbox housing 123 at least partially overlaps the electric machine 11 in the direction of the first axis 101. In the present embodiment, the gearbox housing 123 at least partially overlaps the stator 115 in the direction of the first axis 101. That is, there is at least one line perpendicular to the first axis 101 that passes through both the gearbox housing 123 and the stator 115. Specifically, the second housing space 1232b is at least partially located in the through hole 1153 of the stator core 1151.

Sun gear 121 is connected to the front end of drive shaft 111, and sun gear 121 rotates coaxially with drive shaft 111. The motor front bearing 112 is sleeved on the sun gear 121. The sun gear 121 includes a meshing gear 1211 provided at a front end portion thereof to transmit power to the planetary gear set 122. The sun gear 121 further includes a shoulder portion 1212 provided at a rear end of the meshing tooth portion 1211 and adapted to fit the motor front bearing 112, and a second projection portion 1213 provided at a rear end of the shoulder portion 1212, the second projection portion 1213 being connected to a rear end of the shoulder portion 1212 and extending radially outward. The second protrusion 1213 and the shoulder 1212 form an L-shaped groove, and the motor front bearing 112 is mounted in the L-shaped groove, that is, the rear end surface 1122 of the motor front bearing 112 abuts against the front end surface of the second protrusion 1213. The motor front bearing 112 is axially positioned by the first and

second bosses

1232c, 1213. Wherein the shoulder 1212 of the sun gear 121 is at least partially located in the through hole 1153 of the stator core 1151.

The motor front bearing 112 is axially positioned using a first boss 1232c in the gearbox housing and a second boss 1213 on the sun gear. Meanwhile, the motor front bearing 112, the gear box shell 123 and the stator 115 have an overlapping region in the projection perpendicular to the first axis 101 on the reference plane in the direction of the first axis 101, so that the internal structure of the impact tool is simplified, and the length of the impact tool in the front-back direction is shortened.

A retaining piece 119 is arranged between the sun gear 121 and the front end of the rotor body 1141, and the retaining piece 119 is sleeved at the front end of the driving shaft 111; the holder 119 is held between the rear end surface of the sun gear 121 and the front end surface of the rotor body 1141, that is, one end of the holder 119 abuts against the rear end surface of the second projection 1213 of the sun gear 121, and the other end of the holder 119 abuts against the front end surface of the rotor body 1141. The holder 119 extends in the radial direction of the drive shaft 111, and holds the permanent magnets 116 in the corresponding magnet receiving grooves 1142, and the diameter of the holder 119 is equal to or greater than the vertical distance between the two oppositely disposed magnet receiving grooves 1142. Specifically, the retaining member 119 is a one-piece structure, and the retaining member 119 engages with the end of the permanent magnet 116, thereby preventing the permanent magnet 116 from slipping out of the magnet receiving groove 1142 or moving out of the magnet receiving groove 1142 in the axial direction of the drive shaft 111. In this embodiment, the retainer 119 comprises a layer of epoxy board having a front-to-back dimension in the direction of the first axis 101 of 0.3mm to 0.5mm. In other alternative embodiments, the retaining member 119 comprises multiple layers of epoxy plates of the same diameter or multiple layers of epoxy plates of different diameters that abut against one end of the rotor body 1141 at a diameter equal to or greater than the vertical distance between the oppositely disposed two magnet receiving slots 1142; the holder 119 has a front-rear dimension in the first axial direction of 0.3mm or more and 1mm or less.

The retainer 119 is used for replacing a rotor front end plate to keep the permanent magnet from falling off in the rotor main body, so that the length of the impact tool in the front and back direction is shortened, the installation process of the impact tool is simplified, the product structure is simplified, the cost is saved, and the length of the impact tool in the front and back direction is further shortened by clamping the retainer with the sun gear and the rotor main body in a matching mode.

It is understood that the specific structure, position relationship, connection mode, etc. of the sun gear, the motor and the holder in this embodiment can be applied to other electric tools, such as electric drills, impact drills, electric screwdrivers, electric tools for grinding (sanding machines, flat sanding, angle grinders), hand-held electric tools such as reciprocating saws and multifunctional tools; grass trimmers, lawn mowers, pruners, and electric saws. In the application condition that the miniaturized product is required, the specific structure, the position relation and the connection mode of the sun wheel, the motor and the holder in the embodiment can be changed, and the technical suggestions are given to the change.

The main shaft 131 is formed with a first groove 1311, and the meshing tooth 1211 of the sun gear 121 partially protrudes into the first groove 1311. Preferably, the first groove 1311 is provided in a circular shape. The main shaft 131 is formed at a circumferential outer side thereof with a first surface 1318a, the first surface 1318a extending in the front-rear direction and being located in the first accommodation space 1232 a. The impact tool 1 further includes a spindle bearing 133 for supporting the spindle 131, and the spindle bearing 133 is also disposed in the first accommodation space 1232a described above. Specifically, the outer race of the main shaft bearing 133 abuts against the inner wall of the first housing space 1232a, and the inner race of the main shaft bearing 133 abuts against the first surface 1318a, so that the circumferential position thereof is restricted. The main shaft 131 is formed with a flange 1313 perpendicular to the first axis 101 along the circumferential outer side thereof, and the front end surface of the main shaft bearing 133 abuts against the flange 1313 to achieve axial position limitation thereof.

In the present embodiment, the meshing tooth 1211 of the sun gear 121 and the planetary gear set 122 in which the sun gear 121 meshingly rotates are both disposed in the first accommodation space 1232 a. The tip circle diameter of the meshing tooth 1211 of the sun gear 121 is set to be smaller than the tip circle diameter of the planetary gear set 122, so that the number of meshing teeth of the planetary gear set 122 is greater than the number of meshing teeth 1211 of the sun gear 121. Planetary gear set 122 includes an annulus gear 1221 and a plurality of planetary gears 1222 engaged with annulus gear 1221. An inner ring gear 1221 is engaged around the periphery of the plurality of planetary gears 1222. Ring gear 1221 is connected to gear case 123, and the front end surface of ring gear 1221 abuts against the rear end surface of main shaft bearing 133. The planetary gear set 122 also includes a plurality of planetary gear pins 1223. The planet wheel 1222 is sleeved on a planet wheel pin 1223. Planetary pin 1223 is also fixedly connected to main shaft 131 to transmit the power output from drive shaft 111 to main shaft 131.

The planet pin 1223 in this embodiment is fixedly connected to the main shaft 131 in a cantilever-beam fixing manner. The planetary gear set 122 is provided with a plurality of planetary gears 1222, each planetary gear 1222 is sleeved on one end of a planetary gear pin 1223 extending in the front-rear direction so that the power of the planetary gear 1222 is transmitted to the planetary gear pin 1223. Specifically, the planet 1222 is in meshing engagement with the planet pin 1223. The other end of the planet pin 1223 is fixedly disposed in the main shaft 131 so that the main shaft 131 can rotate simultaneously with the planet pin 1223.

As shown in fig. 1 to 5 and 11 to 18, the impact assembly 13 further includes an elastic member. The impact block 134 is supported on the main shaft 131 and is reciprocally slidable in the front-rear direction with respect to the main shaft 131. The resilient member provides a force to impact block 134 to close anvil 135. In a second projection plane perpendicular to the first axis 101, a projection of the rear end of the elastic element onto the second projection plane in the direction of the first axis 101 is located inside a projection of the front end of the elastic element onto the second projection plane in the direction of the first axis 101. That is, the front dimension of the elastic element is larger than the rear dimension. In this embodiment, the elastic element is a spring 132 sleeved on the outer side of the main shaft. The spring 132 extends in the fore-and-aft direction and connects the main shaft 131 and the impact block 134 to achieve a cushioning effect during impact and to reset the impact block 134. Further, the spring 132 is a frustoconical coil spring, and the outer diameter of the rear end 132a of the spring 132 is smaller than the outer diameter of the front end 132b of the spring 132.

In other alternative embodiments, the elastic element is a non-circular spring, as long as the elastic element satisfies that its rear end projection onto the second projection plane in the direction of the first axis 101 is located inside its front end projection onto the second projection plane in the direction of the first axis 101.

In the present embodiment, the main shaft 131 is further formed with a second groove 1312. Specifically, the second groove 1312 is annular and formed radially outward of the first groove 1311. Second groove 1312 has an opening direction opposite to the front-rear direction of first groove 1311, toward impact block 134. The first groove 1311 and the second groove 1312 have an overlapping area in a projection perpendicular to the first axis 101 on a reference plane along the first axis 101. The rear end 132a of the spring 132 is disposed in the second groove 1312, and abuts against the bottom surface 1312a of the second groove 1312 to position the rear end 132 a. The front end 132b of the spring 132 is fitted into the rear end of the impact block 134, the impact block 134 is formed at the rear end with an annular groove 1341 opening toward the rear side, the annular groove 1341 is coaxial with the impact block 134, and the front end 132b of the spring 132 is fitted into the annular groove 1341 to position the front end 132b of the spring 132. The annular groove 1341 includes an inner ring portion 1342 located inside the spring 132 and an outer ring portion 1343 located outside the spring 132. The outer diameter of the inner ring portion 1342 is smaller than the inner diameter of the second groove 1312, and the inner diameter of the outer ring portion 1343 is larger than the outer diameter of the second groove 1312.

Wherein the outer diameter of the front end 132b of the spring 132 is greater than the outer diameter of the rear end 132a of the spring 132. Thereby, the diameter dimension of the second groove 1312 can be reduced, so that the diameter dimension of the impact tool, i.e., the outer peripheral diameter dimension of the outer casing 15, can be reduced by 1.0 to 4.0mm.

During operation of the impact tool 1, the impact block 134 reciprocates back and forth relative to the spindle in a prescribed stroke in the direction of the spindle axis, which coincides with the first axis 101 in this embodiment; the impact block 134 includes a first position that moves rearwardly to a distal-most position and a second position that moves forwardly to a distal-most position wherein the first end teeth 1344 of the impact block 134 engage the anvil 135, i.e., the forward end of travel of the impact block 134 is stopped by the anvil 135. Fig. 14 to 15b show the first position and fig. 12 to 13b show the second position. Inner ring portion 1342 is always positioned inside spring 132 during movement of impact block 134 between the first and second positions. When the impact block 134 is in the first position, in a first projection plane parallel to the first axis 101, a projection of the spring 132 onto the first projection plane in a direction perpendicular to the first axis 101 is located within a projection of the impact block 134 onto the first projection plane in a direction perpendicular to the first axis 101. In the present embodiment, the second groove 1312 is at least partially fitted into the annular groove 1341, and the rear end of the inner ring portion 1342 of the impact block 134 abuts against the bottom surface 1312a of the second groove 1312. Specifically, the inner ring portion 1342 includes an outer side wall 1342a located on the spring 132 side and an inner side wall 1342b formed to allow the spindle to pass through the impact block 134. The outer side wall 1342a is tapered and the outer diameter of the rear end of the outer side wall 1342a is smaller than the inner diameter of the rear end 132a of the spring 132 to ensure that the inner ring portion 1342 is always located inside the spring 132 during movement of the impact block 134 between the first and second positions.

The front end surface of the impact block body 134a is further provided with a pair of first ball grooves 1345 which open forward and extend backward in the front-rear direction. The main shaft 131 is further formed at an outer surface thereof with a V-shaped second ball groove 1314.

Impact assembly also includes a ball 1315, ball 1315 spanning first ball slot 1345 and second ball slot 1314 to couple impact block 134 with spindle 131. In this embodiment, the ball 1315 is a steel ball.

As spindle 131 rotates, the movement of ball 1315 within second ball slot 1314 allows impact block 134 to move in a fore-aft direction relative to spindle 131. Specifically, when the impact tool 1 is unloaded or lightly loaded, the impact assembly 13 does not impact, the impact assembly 13 performs a transmission function, the impact block 134 is located at the second position, and the rotation of the driving shaft 111 is transmitted to the main shaft 131 through the transmission assembly 12, so that the main shaft 131 rotates. Since the main shaft 131 rotates the impact block 134 by means of the ball 1315 and the first end teeth 1344 of the impact block 134 are engaged with the second end teeth 1351 of the anvil 1411, and the anvil 135 is rotated, the output shaft 141 and the working head mounted on the output shaft 141 are rotated. When a load is applied to the impact tool 1, the rotation of the output shaft 141 is hindered, and the output shaft 141 cannot rotate with the main shaft 131 due to the difference in magnitude of the load, and may completely stop rotating even if the rotation speed is reduced. However, as the spindle 131 continues to rotate, the ball 1315 at the rear end of the first ball slot 1345 rolls along the second ball slot 1314 of the spindle 131 in the backward direction, so that the impact block 134 is displaced in the backward direction in the axial direction, i.e. to the first position of the impact block 134, and the impact block 134 presses the spring 132 until the impact block 134 is completely disengaged from the anvil 135, at which time the impact block 134 is in the first position. The spring 132 rebounds axially to apply force to the impact block 134, and the rolling ball 1315 rolls along the second ball groove 1314, so that the rolling ball advances while rotating, at this time, the relative rotation speed between the impact block 134 and the anvil 135 is the rotation speed of the impact block 134, when the impact block 134 rotates to be in contact with the anvil 135, an impact force is applied to the anvil 135, under the action of the impact force, the output shaft 141 continuously rotates for a certain angle against the load, then the output shaft 141 stops rotating again, and the processes are repeated, so that the impact block 134 applies a rotational striking force intermittently to improve the output force.

In this embodiment, second ball recess 1314 on spindle 131 is recessed inward and disposed on an outer sidewall opposite inner sidewall 1342b of impact block 134. The first ball slot 1345 of the impact block 134 extends along the inner side wall 1342b toward the rear end in the front-rear direction.

The second ball recess 1314 is positioned behind the front face 134b of the impact block body 134a at all times during movement of the impact block 134 between the first and second positions. In this embodiment, when the impact block 134 moves to the first position, the farthest end of the front end of the second ball groove 1314 is at least flush with the front end surface 134b of the impact block body 134a, and preferably, the farthest end of the front end of the second ball groove 1314 is located at the rear end of the front end surface 134b of the impact block body 134 a.

A rolling ball mounting groove 1346 is further provided at the front end of the first ball groove 1345. The ball mounting slot 1346 guides the ball 1315 into the first ball slot 1345 and the second ball slot 1314. The ball mounting groove 1346 includes: a first opening 1346a facing the front side of the impact block, a second opening 1346b for the ball 1315 to leave the ball mounting groove 1346, and a connecting groove 1346d, the connecting groove 1346d communicating the first opening 1346a with the second opening 1346b; specifically, the ball mounting groove 1346 extends along the first axis 101, and is recessed along the radial direction of the impact block 134, and the recessed depth is greater than the first ball groove 1345. A first opening 1346a is provided in the front face 134b of the impact block body for entry of the ball 1315 into the ball mounting slot 1346. A second opening 1346b is provided on a sidewall of the first ball groove 1345 for allowing the ball 1315 to enter an impact lane consisting of the first ball groove 1345 and the second ball groove 1314. In this embodiment, the first opening 1346a and the second opening 1346b communicate in order to simplify the part mold and the part mounting process. The vertical distance from the rear end of the second opening 1346b to the front end face 134b of the impact block body is L3, and the vertical distance from the rear end of the first ball groove 1345 to the front end face 134b of the impact block body is L4. Wherein the ball 1315 is located within the rear end of the first ball slot 1345 when impact block 134 is moved to the second position. The diameter of the rolling ball is D1, L4-L3 is more than or equal to 0.5+ D1 and less than or equal to 1.5D1, and further L4-L3= D1+0.5.

When the rolling ball is installed into the impact lane composed of the first ball groove 1345 and the second ball groove 1314, the rolling ball needs to be installed in the rolling ball installation groove 1346; rotating and moving the ball mounting slot 1346 toward the rear end, i.e., rotating and moving the impact block 134, the ball 1315 enters the impact lane after the ball mounting slot 1346 is aligned with the second ball slot 1314; the optimized distance between the ball mounting groove 1346 and the first ball groove 1345 is equivalent to the installation dimension which needs to be reserved when the ball 1314 enters the impact fairway, and the impact block 134 is matched with the main shaft 131, and the installation dimension basically does not contribute to the impact process, so that the length of the main shaft 131 can be reduced by reducing the installation dimension, and the rear end of the inner ring part 1342 of the impact block 134 is abutted against the bottom surface 1312a of the second groove 1312 when the impact block 134 moves to the first position. So that the contact length of the main shaft 131 and the impact block 134 can be sufficiently increased. Further, the length of the spindle can be reduced, thereby reducing the length of the impact tool in the forward and rearward direction, while reducing or not affecting the overall length of the second ball slot 1314 and the first ball slot 1345, thereby reducing the impact force impact on the impact assembly.

As shown in fig. 19 to 22, the second embodiment of the present solution is different from the first embodiment in the connection manner of the transmission assembly 22, the motor 21 and the impact assembly 23, and the specific structure of the transmission assembly 22 and the motor 21.

In the present embodiment, the motor 21 includes: a stator 215, a rotor 214, and a driving shaft 211 connected to or formed on the rotor 214, the driving shaft 211 rotating about the first axis 201. The rotor 214 of the motor 21 is coaxially fitted in the stator 215, that is, the motor 21 is an inner rotor motor.

The transmission assembly 22 is disposed between the motor 21 and the impact assembly 23. The transmission assembly 22 includes: a sun gear 221 and a planetary gear set 222 rotating in mesh with the sun gear 221.

The stator 215 includes: stator core 2151, stator winding 2152 wound on stator core 2151, and stator front end plate 2154 disposed at the front end of stator core 2151, stator core 2151 is provided with through hole 2153, and rotor 214 is disposed in the through hole. The rotor 214 includes: a rotor body 2141 inside the through hole of the stator 215 and a rotor front end plate 2143. The rotor front end plate 2143 is disposed at the front end of the rotor main body 2141, and both ends of the driving shaft 211 pass through the rotor main body 2141. The portion of the front end of the driving shaft 211 beyond the rear end of the rotor main body 2141 is connected to a fan 217 for dissipating heat from the motor 21. The drive shaft 211 passes through the rotor front end plate 2143, and the drive shaft 211 is fixedly connected or integrally formed with the rotor front end plate 2143. The sun gear 221 is connected to or formed at the front end of the drive shaft 211, and in the present embodiment, the sun gear 221 is provided on the front end surface of the rotor front end plate 2143. The sun gear 221 rotates coaxially with the drive shaft 211. Specifically, the sun gear 221 is fixedly connected or integrally formed with the driving shaft 211, or the sun gear 221 is fixedly connected or integrally formed with the rotor front end plate 2143, or the sun gear 221, the driving shaft 211 and the rotor front end plate 2143 are fixedly connected or integrally formed. The front end of the driving shaft 211 beyond the front end plate 2143 of the rotor is supported by a front bearing 212 of the motor. The motor front bearing 212 is provided at the front end of the sun gear 221. In the present embodiment, the sun gear 221 includes: a meshing tooth portion 2211 meshing with the planetary gear set 222, and a connecting shaft 2214 provided on the front side of the meshing tooth portion 2211. The connecting shaft 2214 and the driving shaft 211 rotate coaxially, and the motor front bearing 212 is sleeved on the connecting shaft 2214.

And an impact assembly 23 for outputting an impact force. The impact assembly 23 includes a main shaft 231, an impact block 234 fitted around the outer periphery of the main shaft 231, an anvil 235 provided at the front end of the impact block 234, and a spring 232. The impact block 234 is supported on the main shaft 231 and is reciprocally slidable in the front-rear direction with respect to the main shaft 231. The spring 232 extends in the fore-and-aft direction and connects the main shaft 231 and the impact block 234 to achieve a cushioning effect during impact and to reset the impact block 234.

The planetary gear set 222 includes an annular gear 2221 and a plurality of planet gears 2222 meshed with the annular gear 2221. The ring gear 2221 is engaged around the plurality of planetary gears 2222. Of these, ring gear 2221 is provided on stator 215. In this embodiment, the ring gear 2221 is disposed on the stator front end plate 2154, and the ring gear 2221 is fixedly connected to or integrally formed with the stator front end plate 2154, that is, the ring gear 2221 and the stator front end plate 2154 may be two separate components or may be integrally formed as a single component. Specifically, the stator front end plate 2154 is provided with an internal tooth structure on the inner side thereof by adopting a powder metallurgy process, so that a ring gear 2221 structure is formed.

The planetary gear set 222 also includes a plurality of planetary gear pins 2223. The planet gear 2222 is sleeved on the planet gear pin 2223 and is meshed with the planet gear pin 2223. The planet pin 2223 is also fixedly connected to the main shaft 231 to transmit the power output from the drive shaft 211 to the main shaft 231. In this embodiment, the planet pin 2223 is fixedly connected to the main shaft 231 in a cantilever-beam fixing manner. Each planet gear 2222 is fitted over one end of a planet gear pin 2223 extending in the front-rear direction so that power on the planet gear 2222 is transmitted to the planet gear pin 2223. The sun gear 221 and the planetary gear set 222 form a meshing tooth portion 2211 that transmits power, and the tip circle diameter of the sun gear 221 is set smaller than the tip circle diameter of the planetary gear set 222 so that the number of meshing teeth of the planetary gear set 222 is larger than the number of meshing tooth portions 2211 of the sun gear 221. The other end of the planet pin 2223 is fixedly disposed within the main shaft 231 so that the main shaft 231 can rotate simultaneously with the planet pin 2223.

In the present embodiment, the ring gear 2221 is structurally connected to the stator 215, and more specifically, the ring gear 2221 and the stator 215 are integrally formed as a single unit, so that the axial length of the impact tool is shortened, and the internal structure of the impact tool is more compact. At least the wall thickness of the gearbox housing can be reduced compared to the first embodiment; further, the distance from the rear end surface of the ring gear 2221 to the front end surface of the stator 215 can be reduced, and the axial length can be shortened by 6mm to 11mm according to the current product size.

The main shaft 231 is formed with a first groove opening toward the rear end, which is coaxial with the main shaft 231 and provided with a circular shape in this embodiment. The motor front bearing 212 is embedded in the first groove, specifically, an outer ring of the motor front bearing 212 abuts against an inner wall of the first groove, and an inner ring of the motor front bearing 212 abuts against the connecting shaft 2214 of the sun gear 221.

It will be appreciated that the present embodiment is equally applicable to other power tools, for example, electric drills, impact drills, power screwdrivers, impact screwdrivers and other power tools with a geared drive, in particular, power tools that use planetary gears for rotational drive.

As shown in fig. 23, as a third embodiment of the present solution, it is different from the second embodiment in that the motor is directly connected to the impact assembly, and the transmission assembly is eliminated.

The motor 31 includes: a stator 315, a rotor 314 and a driving shaft 311 connected or formed on the rotor 314, wherein the driving shaft 311 rotates around the first axis 301, in this embodiment, the rotor 314 of the motor 31 is coaxially sleeved in the stator 315, that is, the motor 31 is an inner rotor motor. The driving shaft 311 is directly connected to the main shaft 331 through a connection member, that is, the driving shaft 311 is directly connected to the main shaft 331, the rotation speed of the motor 31 is substantially the same as that of the main shaft 331, and the output torque of the driving shaft 311 is substantially the same as that of the input torque to the main shaft 331. In other alternative embodiments, the motor 31 is an outer rotor motor, a brush motor, or other motor structure, and the motor 31 serves as a power supply source, and the structural form of the motor does not affect the protection scope of the present embodiment.

The drive shaft 311 has an outer spline 3111 at its front end, and the main shaft 331 has an inner spline 3311 at its rear end. As an alternative embodiment, the front end portion of the driving shaft 311 and the rear end of the main shaft 331 are respectively provided with a pin shaft connection structure, a flange connection structure, and an opposite-pole connection structure, which are matched with each other, and as long as the connection structures that can achieve the coaxiality between the driving shaft 311 and the main shaft 331 and have no transmission ratio all belong to the protection content of this embodiment, which is not described herein again.

A main shaft bearing 333 is provided at a rear end of the main shaft 331, the main shaft bearing 333 is provided outside the main shaft 331, and a movement of the main shaft 331 perpendicular to the first axis 301 is restricted by the main shaft bearing 333 while supporting a front end of the drive shaft 311.

In the impact tool described in the above embodiments, as shown in fig. 1 to 3, the length L from the outer side wall 156 of the rear end of the housing to the front end of the anvil 135, that is, the axial length L of the impact tool, can be reduced, and the technical solutions in the above embodiments may be used alone or in combination of several technical solutions, so as to reduce the axial length of the impact tool according to the needs of the actual impact tool. In the prior published products at present, the overall axial length of the impacting tool is 120mm, and the peripheral diameter of the impacting tool is 61mm, but the prior product size still can not meet the requirement of customers on product miniaturization. Specifically, in the first embodiment of the present application, the length L of the outer side wall 156 of the rear end of the housing to the front end of the anvil 135 may be shorter than that of the prior art (120 mm), for example, the length L is less than 114mm, further, the length L is less than 97mm, and further, the length L is less than 90mm. After shortening the axial dimension of the motor, the length L of the outer side wall 156 of the rear end of the housing to the front end of the anvil 135 is 84mm or more and 86mm or less.

In the first embodiment of the present application, the axial length of the transmission assembly, specifically, the length L1 from the rear end face of the gear box housing 123 to the front end of the anvil 135 is shortened, for example, the length L1 is less than 74mm, further, the length L1 is less than 66mm, and further, to ensure that the output impact force reaches the use standard, L1 is greater than or equal to 59mm and less than or equal to 66mm.

The outer peripheral diameter D of the housing 15 may be smaller than that of the prior art (61 mm), and when the length L from the outer side wall 156 of the rear end of the housing to the front end of the anvil 135 is 97mm or less and 84mm or more, the outer peripheral diameter D of the housing 15 is 60mm or less, and further, the outer peripheral diameter D of the housing 15 is 58mm or less and the outer peripheral diameter D of the housing is 56mm or more.

In the second embodiment of the present application, the length L of the outer side wall 156 of the rear end of the housing to the front end of the anvil 135 is further shortened than that in the first embodiment, and L is 78mm or more and 80mm or less.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by adopting equivalent replacement or equivalent transformation modes fall within the protection scope of the present invention.

Claims

1. An impact tool, comprising:

a housing;

a motor accommodated in the housing; the motor includes: a rotor and a driving shaft formed or connected to the rotor and rotating with a first axis as a shaft; the rotor includes: a rotor body and a permanent magnet disposed in the rotor body;

an impact assembly for providing an impact force;

a transmission assembly for transmitting rotation of the motor to the impact assembly; the transmission assembly includes: a sun gear connected to or formed at a front end of the driving shaft;

it is characterized in that the preparation method is characterized in that,

also includes;

a holder that holds the permanent magnet in the rotor body; the retaining member is disposed around the drive shaft and is sandwiched and fixed by the sun gear and the rotor body.

2. The impact tool of claim 1, wherein a plurality of said permanent magnets are disposed in said rotor, said retainer being sleeved outside said drive shaft, said retainer engaging each of a plurality of said permanent magnets.

3. The impact tool of claim 1, wherein said retainer is of unitary construction.

4. The impact tool according to claim 1, wherein a front-rear dimension of the holder in the first axial direction is 0.3mm or more and 1mm or less.

5. The impact tool of claim 1, wherein said motor further comprises a stator, said rotor being disposed coaxially with and within said stator.

6. The impact tool of claim 1, further comprising: a motor front bearing for supporting a front end portion of the driving shaft; the transmission assembly further includes: a gearbox housing, the impact assembly at least partially disposed within the gearbox housing; the sun gear is at least partially disposed within the gearbox housing; the front bearing of the motor is sleeved on the sun gear; the motor front bearing is arranged in the gearbox shell.

7. The impact tool of claim 6, wherein said gearbox housing at least partially overlaps said motor in said first axial direction; the motor front bearing at least partially overlaps the motor in the first axial direction.

8. The impact tool according to claim 6, wherein the rear end of the sun gear is provided with a second boss portion extending in a direction perpendicular to the first axis, the second boss portion being engaged with a rear end surface of the motor front bearing.

9. An impact tool as claimed in claim 8, wherein said gearbox housing is provided with a first boss portion extending inwardly of said gearbox housing in a direction perpendicular to said first axis, said first boss portion engaging with a front end face of said motor front bearing.

10. A power tool, comprising:

a housing;

a motor accommodated in the housing; the motor includes: a rotor and a driving shaft forming or connecting the rotor and rotating with a first axis as a shaft; the rotor includes: a rotor body and a permanent magnet disposed in the rotor body;

a power output mechanism driven by the drive shaft to output power;

the transmission assembly is used for transmitting the rotation of the motor to the power output mechanism; the transmission assembly includes: a sun gear connected to or formed at a front end of the driving shaft;

it is characterized in that the preparation method is characterized in that,

also includes;

a holder that holds the permanent magnet in the rotor body; the retaining member is disposed around the drive shaft and is sandwiched and fixed by the sun gear and the rotor main body.