Impact tool

Abstract

The application discloses an impact tool, comprising: an impact assembly, which comprises a main shaft driven by a driving shaft of an electric motor, an impact block sleeved on the main shaft and a hammer anvil arranged at the front end of the impact block; the main shaft rotates around a main shaft axis; the impact block comprises an impact block body and end teeth matched with the hammer anvil; the impact assembly further comprises: a rolling ball arranged in a first ball groove arranged on the impact block and a second ball groove arranged on the main shaft, so as to connect the impact block and the main shaft; the impact block reciprocates back and forth along the main shaft axis direction at a specified stroke relative to the main shaft; the impact block comprises a first position of the farthest end of backward movement and a second position of the farthest end of forward movement; when the impact block moves between the first position and the second position, the second ball groove is always located at the rear of the front end surface of the impact block body. The above scheme can provide an impact tool with simple structure, compact volume and short overall length.

Description

Technical Field

[0001] This invention relates to a power tool, and more specifically to an impact tool. Background Technology

[0002] Impact tools are capable of outputting rotational motion with a certain impact frequency, including but not limited to impact wrenches and impact screwdrivers. For example, impact wrenches are used to tighten bolts and nuts, while impact screwdrivers are typically used to loosen or tighten screws. To achieve rotational motion with a certain impact frequency, impact tools need to include an output component for outputting rotational force, as well as an impact component for periodically impacting the output component. This results in a relatively large overall size for the impact tool. In some confined working conditions, a large impact tool cannot be used, leading to reduced efficiency during installation or disassembly. Summary of the Invention

[0003] The purpose of this invention is to provide an impact tool to solve the problem that the large size of existing impact tools leads to low efficiency when installing or disassembling them in corners or confined spaces.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] An impact tool includes: a housing; a motor housed within the housing, the motor including or connected to a drive shaft for outputting power and rotating about a first axis; an impact assembly for providing impact force; including a main shaft driven by the drive shaft, an impact block sleeved on the main shaft, and a hammer anvil disposed at the front end of the impact block; the main shaft rotates about its axis; the impact block includes an impact block body and end teeth that mate with the hammer anvil; the impact assembly further includes: a ball spanning a first ball groove on the impact block and a second ball groove on the main shaft, connecting the impact block and the main shaft; the impact block reciprocates back and forth relative to the main shaft along the axis of the main shaft with a predetermined stroke; the impact block includes a first position where it moves backward to its furthest point and a second position where it moves forward to its furthest point; when the impact block moves between the first and second positions, the second ball groove is always located behind the front end face of the impact block body.

[0006] In some embodiments, the impact assembly further includes: an elastic element that provides a force to the impact block to bring it closer to the anvil; the two ends of the elastic element are respectively connected to a spindle and the impact block; the spindle includes a plane for abutting the elastic element, and when the impact block is in a first position, the rear end face of the impact block at least partially engages with the plane.

[0007] In some embodiments, the second position of the impact block is locked onto the hammer anvil.

[0008] In some embodiments, the spindle and the drive shaft rotate coaxially, and the first axis coincides with the spindle axis.

[0009] In some embodiments, a first ball groove is disposed on the front end face of the impact block and extends rearward along the first axis; a second ball groove is disposed on the outer surface of the main shaft and extends radially inward along the main shaft.

[0010] In some embodiments, the diameter of the end of the elastic element connected to the main shaft is smaller than the diameter of the end of the elastic element connected to the impact block.

[0011] In some embodiments, the impact block body is provided with a ball mounting groove; the ball mounting groove guides the ball into a first ball groove and a second ball groove; the ball mounting groove includes a second opening for the ball to leave the ball mounting groove; the vertical distance from the rear end of the second opening to the front end face of the impact block body is L3; the vertical distance from the rear end of the first ball groove to the front end face of the impact block body is L4; the diameter of the ball is D1, wherein 0.5+D1≤L4-L3≤1.5D1.

[0012] In some embodiments, the ball mounting groove is disposed at the front end of the first ball groove, and the ball mounting groove further includes a first opening formed on the front end face of the impact block body.

[0013] In some embodiments, when the impact block is in the second position, the rolling ball is located at the rear end of the first ball groove.

[0014] In some embodiments, the impact block forms an annular groove with an opening facing the motor at its rear end, and at least a portion of the elastic element is disposed in the annular groove; when the impact block moves to a first position, the rear end face of the annular groove abuts against the plane of the spindle used to abut the elastic element.

[0015] An impact tool includes: a housing; a motor housed within the housing, the motor including or connected to a drive shaft for outputting power and rotating about a first axis; an impact assembly for providing impact force; comprising a main shaft driven by the drive shaft to rotate, an impact block sleeved on the main shaft, and a hammer anvil disposed at the front end of the impact block; the main shaft rotates about its axis; the impact block includes an impact block body and end teeth that mate with the hammer anvil; the impact assembly further includes: a ball spanning a first ball groove on the impact block and a second ball groove on the main shaft, connecting the impact block and the main shaft; the impact block travels a predetermined stroke relative to the main shaft along the axis of the main shaft. The impact block slides back and forth; it includes a first position where it moves backward to the farthest point and a second position where it moves forward to the farthest point; the impact block body is provided with a ball mounting groove; the ball mounting groove extends backward from the front end of the impact block body; the ball mounting groove guides the ball into the first ball groove and the second ball groove; the ball mounting groove includes a second opening for the ball to leave the ball mounting groove; the vertical distance from the rear end of the second opening to the front end face of the impact block body is L3; the vertical distance from the rear end of the first ball groove to the front end face of the impact block body is L4; the diameter of the ball is D1, where D1+0.5≤L4-L3≤1.5D1.

[0016] This invention provides an impact tool that, by reasonably setting the lengths of the second ball groove and the impact block, as well as the front-to-back length of the ball mounting groove, fully utilizes the contact length of the second ball groove and the impact block, thereby reducing the length of the spindle and thus shortening the length of the impact tool in the first axial direction. At the same time, it reduces or eliminates the impact on the total length of the second ball groove and the first ball groove, thereby reducing the impact force on the impact assembly. Attached Figure Description

[0017] Figure 1 This is a structural diagram of the first embodiment in this application;

[0018] Figure 2 yes Figure 1 Another perspective;

[0019] Figure 3 yes Figure 1 A partial sectional view of the first embodiment;

[0020] Figure 4 yes Figure 3 A partially exploded view of the first embodiment, excluding the outer shell and hammer shell;

[0021] Figure 5 yes Figure 4 Another perspective;

[0022] Figure 6 yes Figure 5 A partially exploded view of the motor in the first embodiment, used to illustrate the motor's fan;

[0023] Figure 7 yes Figure 1 A diagram of the fan structure of the first embodiment;

[0024] Figure 8 yes Figure 3 A partial image in the image, with the outer shell removed;

[0025] Figure 9 yes Figure 4 A partially exploded view of the motor and sun gear in the first embodiment;

[0026] Figure 10 yes Figure 9 A sectional view after assembly;

[0027] Figure 11 yes Figure 3 The partial view in the image is used to show the drive shaft, front motor bearing, transmission assembly, spindle, and spindle bearing of the impact tool.

[0028] Figure 12 yes Figure 1 A schematic diagram of the second position of the impact block in the first embodiment;

[0029] Figure 13a yes Figure 1 Another perspective of the plan view;

[0030] Figure 13b yes Figure 13a A sectional view of AA;

[0031] Figure 14 yes Figure 1 A schematic diagram of the first position of the impact block in the first embodiment;

[0032] Figure 15a yes Figure 14 Another perspective of the plan view;

[0033] Figure 15b yes Figure 15a A cross-sectional view of BB;

[0034] Figure 16 yes Figure 1 A partial perspective view of the main shaft and the impact block in the second position of the first embodiment of the present invention, used to show the first ball groove, the second ball groove and the rolling ball;

[0035] Figure 17 yes Figure 16 A partial sectional view of the exploded diagram, showing one side of the rolling ball located in the first ball groove and the other side of the rolling ball located in the second ball groove;

[0036] Figure 18 yes Figure 1 A structural diagram of the impact block in the first embodiment;

[0037] Figure 19 This is a partial cross-sectional view of the second embodiment of this application;

[0038] Figure 20 yes Figure 19 An exploded view of a portion of the second embodiment;

[0039] Figure 21 yes Figure 20 Another perspective;

[0040] Figure 22 yes Figure 19 An exploded view of the motor and transmission assembly components in the second embodiment;

[0041] Figure 23 This is a partial cross-sectional view of the third embodiment of this application. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0043] To clearly illustrate the technical solution of the present invention, the following are also defined: Figure 1 The top, bottom, front, and back sides are shown.

[0044] like Figures 1 to 18 The power tool shown is a first embodiment of the present application. The power tool is an impact tool 1, which is specifically an impact screwdriver for tightening screws, or an impact wrench for tightening bolts or nuts.

[0045] The impact tool 1 includes a motor 11, a transmission assembly 12, an impact assembly 13, a power output assembly 14, and a housing 15. The motor 11, transmission assembly 12, impact assembly 13, and power output assembly 14 are arranged sequentially in the front-to-back direction within the housing 15.

[0046] The motor 11 includes or is connected to a drive shaft 111 that is rotatable relative to the housing 15 about a first axis 101. The drive shaft 111 is used to output power. In this embodiment, the drive shaft 111 is formed in the rotor 114 of the motor 11. In other embodiments, the drive shaft 111 may also be other rotating shafts that are drively connected to the rotor 114 of the motor 11.

[0047] The outer casing 15 also forms or is connected to a grip portion 151 for user operation. The grip portion 151 and the outer casing 15 form a T-shaped or L-shaped structure for easy gripping and operation by the user. One end of the grip portion 151 is connected to a power supply device 16. The power supply device 16 is detachably connected to the outer casing 15. Of course, the power supply device 16 can also be set to mains power. In this embodiment, the power supply device 16 is a battery pack. The hammer shell 153 is connected to the front end of the outer casing 15, and the impact assembly 13 is at least partially disposed within the hammer shell 153.

[0048] The power output assembly 14 includes an output shaft 141. The front end of the output shaft 141 is provided with a receiving part 1412, which can receive corresponding working heads, such as screwdrivers, drill bits, wrenches, etc., when performing different functions.

[0049] Understandably, in other alternative embodiments, the power output assembly may also be a mowing rope for a lawnmower, a grinding disc for a power tool, a sandpaper-like working element, a lawn mowing blade, or other types of actuators driven by a motor to perform a working function.

[0050] like Figures 1 to 8As shown, when the motor 11 runs at high speed, it generates a lot of heat. Due to the current flowing through the stator windings, the coils heat up, and this heat accumulates inside the housing 15. Excessive heat can cause a series of problems, such as a shorter time that it can maintain high power output, failing to meet the actual needs of the impact tool. To improve the heat dissipation efficiency of the motor 11 and effectively dissipate the heat, a fan 117 is installed on the motor 11. One end of the motor 11 is used for driving force output and is connected to the power output assembly 14 via the transmission assembly 12 and the impact assembly 13; the other end is connected to the fan 117. In this embodiment, the fan 117 is installed at the rear end of the motor 11. In other alternative embodiments, depending on the installation position of the motor within the housing and the layout of the driving force output relationship in the impact tool, the fan 117 can also be located at other positions on the motor 11. At the position corresponding to the fan 117, a heat dissipation hole 154 is provided on the housing 15, connecting the inside and outside of the housing 15, serving as an air outlet. The air inlet is located at the front end of the motor 11. The fan 117 is driven by the drive shaft 111 to rotate around a second axis. In this embodiment, the fan 117 is directly sleeved on the drive shaft 111 through the center hole 1173, and the second axis coincides with the first axis 101. In other embodiments, the drive shaft can also be connected to the fan 117 through other mechanisms with transmission ratios. It is not limited to whether the specific fan 117 is directly driven or indirectly driven by a motor. The positional relationship between the second axis and the first axis depends on the transmission method between the fan 117 and the drive shaft, including but not limited to being at an angle to each other or parallel to each other; the drive shaft 111 only needs to be able to drive the fan 117 to rotate.

[0051] The impact tool 1 also includes a rear bearing 113 for the motor, which supports the rear end of the drive shaft 111. The rear bearing 113 is detachably installed inside the housing 15. The outer ring of the rear bearing 113 engages with the rear end of the housing 15, and the inner ring of the rear bearing 113 abuts against the outer peripheral surface of the drive shaft 111. In this embodiment, the inner sidewall 157 of the rear end of the housing is provided with a bearing mounting groove 155, and the rear bearing 113 is detachably installed in the bearing mounting groove 155.

[0052] The fan 117 includes fan blades 1171 and a fan base plate 1172 for mounting the fan blades 1171. A central hole 1173 of the fan 117 is located on the fan base plate 1172. In this embodiment, the central hole 1173 of the fan 117 is located at the geometric center of the fan base plate 1172. The fan blades 1171 are circumferentially arranged on one side of the fan base plate 1172. Specifically, the fan blades 1171 are at least partially located on the front end face of the fan base plate 1172, and the rear side of the fan base plate 1172 faces the rear bearing 113 of the motor. The fan blades 1171 all rotate around the drive shaft 111 about a first axis 101. The rear bearing 113 of the motor and the fan 117 at least partially overlap along the direction of the first axis 101. That is, there is at least one straight line perpendicular to the first axis 101 that passes through both the rear bearing 113 of the motor and the fan 117. Specifically, the fan base plate 1172 forms a groove 1174 surrounding the central hole 1173 of the fan 117, and the motor rear bearing 113 is at least partially located within this groove 1174. The fan 117 and the motor 11 at least partially overlap along the direction of the first axis 101. This makes the impact tool more compact in the direction of the first axis 101 and shortens the length of the impact tool in the longitudinal direction. Specifically, it shortens the length from the outer side wall 156 of the rear end of the housing to the front end of the impact tool. Based on the existing dimensions of the motor rear bearing, the length in the longitudinal direction can be shortened by at least 6 mm.

[0053] like Figure 7As shown, in this embodiment, the fan base plate 1172 covers a portion of the fan blades 1171 along the direction perpendicular to the first axis 101. Specifically, along the length of the fan blades 1171, the fan base plate 1172 partially covers the fan blades 1171; all the fan blades 1171 form a circular or similar circular outer contour, and the edge contour of the fan base plate 1172 forming the perimeter is located within the outer contour formed by the fan blades. Specifically, along the direction of the first axis 101, with the first axis 101 as the center point, a minimum circle containing the outer contour of the fan base plate 1172 is drawn in a second projection plane perpendicular to the first axis 101, and the radius of this minimum circle is R1; with the first axis 101 as the center point, a minimum circle containing the outer contour of the fan blades 1171 is drawn in a second projection plane perpendicular to the first axis 101, and the radius of this minimum circle is R2; where R1 < R2. In this embodiment, the rear edge of the fan blade 1171 of the fan 117 is flush with or substantially flush with the rear end face of the fan base plate 1172. In this embodiment, the fan 117 structure, which partially covers the fan blade 1171 with the fan base plate 1172 and embeds the fan base plate 1172 into the fan blade 1171, saves on the front-to-back thickness of the fan base plate 1172 along the first axis direction while maintaining the front-to-back dimensions of the fan blade 1171 along the first axis direction. In this embodiment, the front-to-back dimension of the fan blade 1171 along the first axis direction is the height of the fan blade 1171; preferably, the height of the fan blade 1171 is 2.5 mm. This shortens the front-to-back length of the fan 117 along the first axis direction; based on existing fan base plate 1172 dimensions, it can be shortened by at least 1.2 mm in the front-to-back direction along the first axis direction.

[0054] In this embodiment, fan 117 is a centrifugal fan, specifically, a centrifugal fan in which fan base plate 1172 partially covers fan blades 1171. We found that when a fan structure is used where fan base plate 1172 partially covers fan blades 1171 and fan base plate 1172 is embedded in fan blades 1171, the airflow generated by the rotation of the centrifugal fan will cause a certain loss in the gas flow rate inside motor 11, thereby reducing the heat dissipation performance of motor 11. While increasing the fan diameter and fan blade height can increase the fan airflow and improve heat dissipation performance, it will increase the overall size of the impact tool, which does not meet the requirements for product miniaturization. Through research and experimentation, the applicant found that by setting an auxiliary windbreak surface 118 on the side of fan base plate 1172 away from fan blades 1171, and adjusting the gap distance L2 between fan 117 and this auxiliary windbreak surface 118, the gas flow rate inside motor generated by the rotation of centrifugal fan can be changed, thereby improving the heat dissipation performance of motor. Heat dissipation holes 154 are opened on the side of the plane where auxiliary windbreak surface 118 is located, close to the fan. In this embodiment, the heat dissipation hole 154 is located on the front side of the auxiliary windbreak surface 118.

[0055] In this embodiment, to meet the requirements of product miniaturization, an auxiliary wind deflector 118 is disposed on the inner sidewall 157 of the rear end of the housing. The auxiliary wind deflector 118 is perpendicular to the first axis 101, and the heat dissipation hole 154 is formed on the front side of the inner sidewall 157 of the rear end of the housing. The vertical distance L2 between the auxiliary wind deflector 118 and the end face of the fan 117 facing the housing is set to be greater than or equal to 0.9 mm and less than or equal to 1.2 mm. In this embodiment, L2 is the vertical distance between the rear end face of the fan 117 and the inner sidewall 157 of the rear end of the housing.

[0056] Specifically, referring to Table 1, sample number 1 represents the air gap flow rate when using a fan of the prior art. Here, the air gap flow rate of the motor refers to the gas flow rate between the motor rotor 114 and the motor stator 115. Specifically, the prior art fan is a centrifugal fan where the fan base completely covers the fan blades. The fan blade radius R2 = 22.4 mm. The fan base completely covers the fan blades, but the fan blades are not embedded in the fan base; that is, the fan blades are entirely located on the front side of the fan base, and the height of the fan blades is 2.5 mm. Because the fan base completely covers the fan blades, the prior art fan has no auxiliary windbreak surface. Sample numbers 2-9 represent the air gap flow rate when the fan base partially covers the fan blades, where the height of the fan blade 1171 is 2.5 mm, R2 = 22.4 mm, and R1 = 17.5 mm. Based on the controllable manufacturing tolerances, the gap between the rear end face of fan 117 and auxiliary baffle surface 118 was adjusted to 0.6mm, 0.8mm, 1.0mm, 1.1mm, 1.2mm, 1.5mm, 1.8mm, and 2.0mm respectively. With the motor speed and the fan 117 driven by the motor at the same speed, the air gap flow rate of the motor was recorded within the same time interval. Table 1 is obtained.

[0057] Table 1:

[0058]

[0059] When L2 is 0.6mm to 1.0mm, the air gap flow rate increases accordingly with the increase of the gap distance. When L2 is 1.0mm to 1.1mm, the air gap flow rate increases with the increase of the gap distance. When L2 is 1.1mm to 1.2mm, the air gap flow rate begins to decrease with the increase of L2. When L2 is 1.2mm to 2.0mm, the air gap flow rate continues to decrease with the increase of the gap distance. It can be seen that the gap between the auxiliary wind deflector 118 and the rear end face of the fan 117 is not simply positively or negatively correlated with the air gap flow rate. It needs to be adjusted to a suitable distance range to ensure the heat dissipation efficiency of the motor. In the prior art, when the inner wall of the housing of impact tools or power tools is set, its function is to support, fix or accommodate components. It also has a gap with the rear end face of the fan 117. The purpose of this gap is to meet the design or assembly tolerance levels, etc. Therefore, the inner wall of the housing or other planes in this case cannot be considered as not belonging to the auxiliary wind deflector.

[0060] In this application, the applicant discovered through research that when the distance is greater than or equal to 0.9 mm and less than or equal to 1.2 mm, setting a plane can ensure that the airflow of the fan product at the motor cooling location still meets the motor cooling requirements, even when the length of the fan 117 in the front-to-back direction is shorter than that of the existing fan 117. In this case, the plane set according to the design requirements within this distance range serves as an auxiliary windbreak surface. At this time, when the length of the fan 117 in the front-to-back direction is shortened by 40% compared to the existing fan 117, the airflow of the fan 117 in this embodiment can still reach 85% of the airflow of the existing fan. When L2 = 1.1 mm, the airflow of the fan 117 in this embodiment can still reach 86% of the airflow of the existing fan.

[0061] Without changing the size of the fan 117 or affecting the miniaturization of the impact tool 1, the applicant discovered through research and experimentation that adjusting the length of the fan base plate 1172 covering the fan blades 1171 can also achieve the effect of ensuring heat dissipation airflow. Referring to Table 2; where sample number 1 represents the air gap flow rate when using a fan of the prior art, specifically, the prior art fan is a centrifugal fan with the fan base plate completely covering the fan blades, and its fan blade radius R2 = 22.4 mm. The fan base plate completely covers the fan blades, but the fan base plate does not embed the fan blades; that is, the fan blades are completely set on the front side of the fan base plate, and the height of the fan blades is 2.5 mm. Samples 2-10 represent the air gap flow rate when the fan base plate partially covers the fan blades. The fan base plate is embedded in the fan blades, and the rear edge of the fan blade 1171 is flush with the rear end face of the fan base plate 1172. Specifically, R2 = 22.4 mm, L2 = 1.1 mm, and the height of the fan blade is 2.5 mm. The radii R1 of the fan base plate 1172 are 11.5 mm, 12.5 mm, 13.5 mm, 14.5 mm, 15.5 mm, 16.5 mm, 17.5 mm, 18.5 mm, and 19.5 mm, respectively. The air gap flow rate of the motor is recorded within the same time period, with the motor speed and the fan 117 driven by the motor being the same.

[0062] Table 2:

[0063]

[0064] It can be seen that when the radius of R1 is 11.5mm to 12.5mm, the air gap flow rate decreases as the radius of R1 increases; when the radius of R1 is 12.5mm to 14.5mm, the air gap flow rate increases as the radius of R1 increases; and when the radius of R1 is 14.5mm to 19.5mm, the air gap flow rate decreases again as the radius of R1 increases. This shows that the relationship between the fan radius R1 and the air gap flow rate is not simply positive or negative. It needs to be adjusted to a suitable range to ensure the motor's heat dissipation efficiency. Furthermore, to ensure the structural strength of the fan 117, when the fan radius R1 is greater than or equal to 11.5mm and less than or equal to 17.5mm, the motor's air gap flow rate is greater than or equal to 85% of the existing motor air gap flow rate, which can meet the actual needs of impact tools. That is to say, the relationship between the fan radius R1 and the fan base plate is R1 < R2, and 4:8 ≤ R1:R2 ≤ 6.5:8; preferably, R1:R2 = 5:8, at which point L2 = 1.1mm, and the air gap flow rate reaches 88% of the air gap flow rate of the prior art.

[0065] It is understood that the specific structure, positional relationship, and connection method of the fan 117, auxiliary wind deflector 118, and motor 11 in this embodiment can also be applied to other power tools, such as handheld power tools like electric drills, impact drills, electric screwdrivers, grinding power tools (sanders, flat sanders, angle grinders), reciprocating saws, and multi-tools; and outdoor power tools like lawnmowers, lawn trimmers, pruning machines, and chainsaws. In applications requiring miniaturized products, the specific structure, positional relationship, and connection method of the fan 117, auxiliary wind deflector 118, and motor 11 in this embodiment can be reused, and this application has provided technical guidance for such reuse and replacement.

[0066] Impact assembly 13 is used to provide impact force. Impact assembly 13 includes a main shaft 131, an impact block 134 sleeved on the outer periphery of the main shaft 131, and a hammer anvil 135 disposed at the front end of the impact block 134. The hammer anvil 135 includes an anvil seat 1411 and an output shaft 141; the impact block 134 is driven by the main shaft 131, the anvil seat 1411 cooperates with the impact block 134 and is struck by it, and the anvil seat 1411 drives the output shaft 141 to rotate. The impact block 134 includes an impact block body 134a and a pair of first end teeth 1344 radially symmetrically protruding on the front end face 134b of the impact block body 134a; a pair of second end teeth 1351 are radially symmetrically protruding on the rear end face of the anvil seat 1411 opposite to the impact block 134. The output shaft 141 extends out of the hammer shell 153; the output shaft 141 is connected to the anvil 1411. It can be understood that the anvil 1411 and the output shaft 141 can be integrally formed or separate independent parts.

[0067] like Figures 1 to 11 As shown, the rotor 114 of the motor 11 is coaxially fitted within the stator 115, meaning that the motor 11 is an internal rotor motor. The rotor 114 also includes a rotor body 1141 located inside the stator 115 and a plurality of permanent magnets 116. The permanent magnets 116 are housed in corresponding magnet receiving slots 1142 formed on the rotor body 1141. The magnet receiving slots 1142 are substantially consistent with the outer contour of the permanent magnets 116 and extend substantially along the direction of the first axis 101.

[0068] The stator 115 includes a stator core 1151 and a stator winding 1152 wound on the stator core 1151. The stator core 1151 has a through hole 1153, and the rotor 114 is located inside the stator core 1151. When energized, the stator winding 1152 generates a magnetic field, which interacts with the permanent magnet 116 in the rotor 114, causing the rotor 114 to rotate relative to the stator 115.

[0069] like Figure 8As shown, the drive shaft 111 passes through the rotor 114, and both ends of the drive shaft 111 extend beyond the end face of the rotor 114. A front bearing 112 is provided on the portion of the drive shaft 111 extending beyond the front face of the rotor 114 for support. A fan 117 is connected to the portion of the drive shaft 111 extending beyond the rear face of the rotor 114, and a rear bearing 113 is provided for support. The rear bearing 113 is positioned by a housing structure. The front bearing 112 and the motor 11 at least partially overlap along the first axis 101. In this embodiment, the front bearing 112 and the stator 115 at least partially overlap along the first axis 101. That is, there is at least one straight line perpendicular to the first axis 101 that passes through both the front bearing 112 and the stator 115. Specifically, the front bearing 112 is at least partially located in a through hole 1153 on the stator core 1151.

[0070] like Figures 8 to 11 As shown, the drive shaft 111 is connected to a transmission assembly at the portion extending beyond the front end face of the rotor 114. The transmission assembly includes: a gearbox housing 123, a sun gear 121 at least partially disposed within the gearbox housing 123, and a planetary gear set 122 meshing and rotating with the sun gear 121. In this embodiment, the gearbox housing 123 has a first receiving space 1232a located at the front end of the gearbox housing 123 and a second receiving space 1232b located at the rear end of the gearbox housing 123. A portion of the main shaft 131 is disposed within the first receiving space 1232a. The motor front bearing 112 is disposed within the second receiving space 1232b. Specifically, the outer ring of the motor front bearing 112 abuts against the inner wall of the second receiving space 1232b, and the inner ring of the motor front bearing 112 abuts against the drive shaft 111, thereby achieving circumferential limiting of the drive shaft 111. A first protrusion 1232c is provided within the second receiving space 1232b, extending in a direction perpendicular to the first axis 101. The first protrusion 1232c extends inward along the circumference of the second receiving space 1232b. The first protrusion 1232c can form a continuous flange around the circumference of the second receiving space 1232b, or multiple protrusions can be provided at intervals along the circumference of the second receiving space 1232b. The rear end face of the first protrusion 1232c abuts against the front end face 1121 of the motor front bearing 112. The gearbox housing 123 and the motor 11 at least partially overlap along the direction of the first axis 101. In this embodiment, the gearbox housing 123 and the stator 115 at least partially overlap along the direction of the first axis 101. That is, there is at least one straight line perpendicular to the first axis 101 that passes through both the gearbox housing 123 and the stator 115. Specifically, the second receiving space 1232b is at least partially located in the through hole 1153 on the stator core 1151.

[0071] The sun gear 121 is connected to the front end of the drive shaft 111, and rotates coaxially with the drive shaft 111. The front bearing 112 of the motor is fitted onto the sun gear 121. The sun gear 121 includes a meshing tooth portion 1211 at its front end that forms a power transmission connection with the planetary gear set 122. The sun gear 121 also includes a shoulder 1212 located at the rear end of the meshing tooth portion 1211 for fitting the front bearing 112, and a second protrusion 1213 located at the rear end of the shoulder 1212. The second protrusion 1213 is connected to the rear end of the shoulder 1212 and extends radially outward. The second protrusion 1213 and the shoulder 1212 form an L-shaped groove, into which the front bearing 112 is installed; that is, the rear end face 1122 of the front bearing 112 abuts against the front end face of the second protrusion 1213. The front bearing 112 of the motor is axially positioned by a first protrusion 1232c and a second protrusion 1213. The shoulder 1212 of the sun gear 121 is at least partially located in the through hole 1153 on the stator core 1151.

[0072] The front bearing 112 of the motor is axially positioned using the first protrusion 1232c inside the gearbox housing and the second protrusion 1213 located on the sun gear. At the same time, the front bearing 112 of the motor, the gearbox housing 123, and the stator 115 have overlapping areas on the reference plane in the direction of the first axis 101, which simplifies the internal structure of the impact tool and shortens the length of the impact tool in the front-rear direction.

[0073] A retainer 119 is provided between the sun gear 121 and the front end of the rotor body 1141, and the retainer 119 is sleeved on the front end of the drive shaft 111. The retainer 119 is clamped by the rear end face of the sun gear 121 and the front end face of the rotor body 1141. That is, one end of the retainer 119 abuts against the rear end face of the second protrusion 1213 on the sun gear 121, and the other end of the retainer 119 abuts against the front end face of the rotor body 1141. The retainer 119 extends radially along the drive shaft 111 to hold the permanent magnet 116 in the corresponding magnet receiving groove 1142. The diameter of the retainer 119 is equal to or greater than the vertical distance between the two opposing magnet receiving grooves 1142. Specifically, the retainer 119 is an integral structure, engaging with the end of the permanent magnet 116 to prevent the permanent magnet 116 from sliding out of the magnet receiving groove 1142 or moving out of the magnet receiving groove 1142 along the axial direction of the drive shaft 111. In this embodiment, the retainer 119 includes a layer of epoxy board, the front-to-back dimension of which along the first axis 101 is 0.3mm-0.5mm. In other alternative embodiments, the retainer 119 includes multiple layers of epoxy boards of the same diameter or multiple layers of epoxy boards of different diameters, the diameter of which abuts against one end of the rotor body 1141 is equal to or greater than the vertical distance between the two opposing magnet receiving grooves 1142; the front-to-back dimension of the retainer 119 along the first axis is greater than or equal to 0.3mm and less than or equal to 1mm.

[0074] By using retainer 119 instead of rotor front end plate to keep permanent magnets from falling out of rotor body, the length of impact tool in front-back direction is shortened, the installation process of impact tool is simplified, the product structure is simplified, and costs are saved. Using sun gear and rotor body to clamp retainer further shortens the length of impact tool in front-back direction.

[0075] It is understood that the specific structure, positional relationship, and connection method of the sun gear, motor, and retainer in this embodiment can also be applied to other power tools, such as handheld power tools like electric drills, impact drills, electric screwdrivers, grinding power tools (sanders, flat sanders, angle grinders), reciprocating saws, and multi-tools; and outdoor power tools like lawnmowers, lawn trimmers, pruning machines, and chainsaws. In applications requiring miniaturized products, the specific structure, positional relationship, and connection method of the sun gear, motor, and retainer in this embodiment can be reused, and this application has provided technical guidance for such reuse and replacement.

[0076] A first groove 1311 is formed on the main shaft 131, and the meshing teeth 1211 of the sun gear 121 extend into the first groove 1311. Preferably, the first groove 1311 is circular. A first surface 1318a is formed on the outer circumferential side of the main shaft 131, and the first surface 1318a extends in the front-rear direction and is located in the first receiving space 1232a. The impact tool 1 also includes a main shaft bearing 133 for supporting the main shaft 131, and the main shaft bearing 133 is also disposed in the aforementioned first receiving space 1232a. Specifically, the outer ring of the main shaft bearing 133 abuts against the inner wall of the first receiving space 1232a, and the inner ring of the main shaft bearing 133 abuts against the first surface 1318a to achieve circumferential limiting. A flange 1313 perpendicular to the first axis 101 is formed on the outer circumferential side of the main shaft 131, and the front end face of the main shaft bearing 133 abuts against the flange 1313 to achieve axial limiting.

[0077] In this embodiment, both the meshing teeth 1211 of the sun gear 121 and the planetary gear set 122 meshing and rotating with the sun gear 121 are disposed within the first receiving space 1232a. The addendum circle diameter of the meshing teeth 1211 of the sun gear 121 is set smaller than the addendum circle diameter of the planetary gear set 122, such that the number of meshing teeth in the planetary gear set 122 is greater than the number of teeth in the meshing teeth 1211 of the sun gear 121. The planetary gear set 122 includes an internal gear ring 1221 and a plurality of planetary gears 1222 meshing with the internal gear ring 1221. The internal gear ring 1221 meshes around the periphery of the plurality of planetary gears 1222. The internal gear ring 1221 is connected to the gearbox housing 123, and the front end face of the internal gear ring 1221 abuts against the rear end face of the main shaft bearing 133. The planetary gear set 122 also includes a plurality of planetary pins 1223. Planetary gear 1222 is mounted on planetary gear pin 1223. Planetary gear pin 1223 is also fixedly connected to main shaft 131 to transmit the power output from drive shaft 111 to main shaft 131.

[0078] In this embodiment, the planetary pin 1223 is fixedly connected to the main shaft 131 using a cantilever beam fixing method. The planetary gear set 122 is provided with multiple planetary gears 1222, each planetary gear 1222 being fitted onto one end of a planetary pin 1223 extending in the front-rear direction so that the power on the planetary gear 1222 is transmitted to the planetary pin 1223. Specifically, the planetary gear 1222 and the planetary pin 1223 are meshed together. The other end of the planetary pin 1223 is fixedly disposed inside the main shaft 131 so that the main shaft 131 can rotate simultaneously with the planetary pin 1223.

[0079] like Figures 1 to 5 and Figures 11 to 18As shown, the impact assembly 13 also includes an elastic element. The impact block 134 is supported on the main shaft 131 and can slide back and forth relative to the main shaft 131 in the front-to-back direction. The elastic element provides a force to the impact block 134 to bring it closer to the anvil 135. In a second projection plane perpendicular to the first axis 101, the projection of the rear end of the elastic element along the direction of the first axis 101 on the second projection plane is located inside the projection of the front end of the elastic element along the direction of the first axis 101 on the second projection plane. That is, the front end dimension of the elastic element is larger than the rear end dimension. In this embodiment, the elastic element is a spring 132 sleeved on the outside of the main shaft. The spring 132 extends in the front-to-back direction and connects the main shaft 131 and the impact block 134 to achieve a buffering effect during the impact process and to reset the impact block 134. Further, the spring 132 is a truncated cone helical 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.

[0080] In other alternative implementations, the elastic element is a non-circular spring, provided that the projection of the elastic element's rear end along the direction of the first axis 101 onto the second projection plane is located inside the projection of its front end along the direction of the first axis 101 onto the second projection plane.

[0081] In this embodiment, a second groove 1312 is also formed on the main shaft 131. Specifically, the second groove 1312 is annular and formed radially outside the first groove 1311. The second groove 1312 has an opening direction opposite to that of the first groove 1311 in the front-back direction, facing the impact block 134. The first groove 1311 and the second groove 1312 have an overlapping area on the reference plane along the first axis 101 along a projection perpendicular to 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 its rear end 132a. The front end 132b of the spring 132 is fitted into the rear end of the impact block 134. The impact block 134 has an annular groove 1341 with an opening facing the rear at its rear end. The annular groove 1341 is coaxial with the impact block 134. The front end 132b of the spring 132 is embedded in 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.

[0082] In this design, the outer diameter of the front end 132b of the spring 132 is larger than the outer diameter of the rear end 132a of the spring 132. This allows the diameter of the second groove 1312 to be reduced, thereby reducing the diameter of the impact tool, i.e., the outer circumference diameter of the housing 15, by 1.0-4.0 mm.

[0083] During the operation of the impact tool 1, the impact block 134 reciprocates relative to the main shaft along the main shaft axis with a specified stroke. In this embodiment, the main shaft axis coincides with the first axis. The impact block 134 includes a first position where it moves backward to the farthest end and a second position where it moves forward to the farthest end. In the second position, the first end tooth 1344 of the impact block 134 engages with the hammer anvil 135. That is to say, the front end of the stroke of the impact block 134 is stopped by the hammer anvil 135. Figures 14 to 15b The first position is shown. Figures 12 to 13b The second position is shown. During the movement of the impact block 134 between the first and second positions, the inner ring portion 1342 is always located inside the spring 132. When the impact block 134 is in the first position, in a first projection plane parallel to the first axis 101, the projection of the spring 132 along the direction perpendicular to the first axis 101 on the first projection plane is located inside the projection of the impact block 134 along the direction perpendicular to the first axis 101 on the first projection plane. In this embodiment, the second groove 1312 is at least partially embedded in 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 wall 1342a located on the side of the spring 132 and an inner wall 1342b forming a path for the main shaft to pass through the impact block 134. The outer wall 1342a is tapered, and the outer diameter of the rear end of the outer wall 1342a is smaller than the inner diameter of the rear end of the spring 132a, so as to ensure that the inner ring 1342 is always located inside the spring 132 during the movement of the impact block 134 between the first position and the second position.

[0084] The front end face of the impact block body 134a is also provided with a pair of first ball grooves 1345 with openings facing forward and extending backward in the front-rear direction. The outer surface of the main shaft 131 is also formed with a V-shaped second ball groove 1314.

[0085] The impact assembly also includes a ball 1315 that spans the first ball groove 1345 and the second ball groove 1314, thereby connecting the impact block 134 to the main shaft 131. In this embodiment, the ball 1315 is a steel ball.

[0086] When the spindle 131 rotates, the movement of the ball 1315 within the second ball groove 1314 allows the impact block 134 to move relative to the spindle 131 in the front-back direction. Specifically, when the impact tool 1 is unloaded or lightly loaded, the impact assembly 13 does not impact; instead, it acts as a transmission mechanism. The impact block 134 is in the second position, and the rotation of the drive shaft 111 is transmitted to the spindle 131 via the transmission assembly 12, causing the spindle 131 to rotate. Because the spindle 131 rotates the impact block 134 using the ball 1315, and the first end tooth 1344 of the impact block 134 engages with the second end tooth 1351 of the anvil 1411, the hammer anvil 135 rotates, thus causing the output shaft 141 and the working head mounted on the output shaft 141 to rotate. When the impact tool 1 is under load, the rotation of the output shaft 141 is hindered. Due to the varying load magnitude, the output shaft 141 cannot rotate with the spindle 131; its rotational speed may decrease or it may stop rotating completely. However, if the main shaft 131 continues to rotate, the rolling ball 1315 located at the rear end of the first ball groove 1345 will roll backward along the second ball groove 1314 of the main shaft 131, thereby causing the impact block 134 to move backward along the axial direction, that is, to move to the first position of the impact block 134. At the same time, the impact block 134 compresses the spring 132 until the impact block 134 is completely disengaged from the hammer anvil 135. At this time, the impact block 134 is in the first position. The spring 132 rebounds axially and applies force to the impact block 134. The rolling ball 1315 rolls along the second ball groove 1314, thus moving forward while rotating. At this time, the relative rotation speed between the impact block 134 and the hammer anvil 135 is the rotation speed of the impact block 134. When the impact block 134 rotates to contact the hammer anvil 135, it will apply an impact force to the hammer anvil 135. Under the action of this impact force, the output shaft 141 continues to rotate at a certain angle to overcome the load. Then the output shaft 141 stops rotating again. The above process is repeated to realize that the impact block 134 intermittently applies rotational striking force to increase the output force.

[0087] In this embodiment, the second ball groove 1314 on the main shaft 131 is recessed inward and disposed on the outer sidewall opposite to the inner sidewall 1342b of the impact block 134. The first ball groove 1345 of the impact block 134 extends rearward along the inner sidewall 1342b in the front-rear direction.

[0088] During the movement of the impact block 134 between the first and second positions, the second ball groove 1314 is always located behind the front end face 134b of the impact block body 134a. 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 face 134b of the impact block body 134a. Preferably, the farthest end of the front end of the second ball groove 1314 is located at the rear end of the front end face 134b of the impact block body 134a.

[0089] The first ball groove 1345 is further provided with a ball mounting groove 1346 at its front end. The ball mounting groove 1346 guides the ball 1315 into the first ball groove 1345 and the second ball groove 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, wherein the connecting groove 1346d connects the first opening 1346a and the second opening 1346b; specifically, the ball mounting groove 1346 extends along the direction of the first axis 101, and is radially recessed along the impact block 134, with a recess depth greater than that of the first ball groove 1345. The first opening 1346a is formed on the front end face 134b of the impact block body for the ball 1315 to enter the ball mounting groove 1346. The second opening 1346b is located on the side wall of the first ball groove 1345, for allowing the rolling ball 1315 to enter the impact track formed by the first ball groove 1345 and the second ball groove 1314. In this embodiment, to simplify the component mold and component assembly process, the first opening 1346a and the second opening 1346b are connected. 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; 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. When the impact block 134 moves to the second position, the rolling ball 1315 is located inside the rear end of the first ball groove 1345. The diameter of the rolling ball is D1, 0.5+D1≤L4-L3≤1.5D1, and further, L4-L3=D1+0.5.

[0090] When installing the ball into the impact track formed by the first ball groove 1345 and the second ball groove 1314, the ball needs to be installed in the ball mounting groove 1346 first. Rotating and moving the ball mounting groove 1346 rearward causes the impact block 134 to rotate and move rearward. Once the ball mounting groove 1346 is aligned with the second ball groove 1314, the ball 1315 enters the impact track. Optimizing the distance between the ball mounting groove 1346 and the first ball groove 1345 is equivalent to optimizing the installation dimension required for the impact block 134 and the main shaft 131 during the ball 1314's entry into the impact track. This installation dimension contributes little to the impact process, so reducing this dimension can decrease the length of the main shaft 131. This allows the rear end of the inner ring portion 1342 of the impact block 134 to abut against the bottom surface 1312a of the second groove 1312 when the impact block 134 moves to the first position. This significantly increases the contact length between the main shaft 131 and the impact block 134. Furthermore, the length of the spindle can be reduced, thereby shortening the length of the impact tool in the front-to-back direction, while simultaneously reducing or eliminating the impact on the total length of the second ball groove 1314 and the first ball groove 1345, thereby reducing the impact force on the impact assembly.

[0091] like Figures 19 to 22 As shown, the second embodiment of this solution differs from the first embodiment in the connection method of the transmission component 22, the motor 21 and the impact component 23, and the specific structure of the transmission component 22 and the motor 21.

[0092] In this embodiment, the motor 21 includes a stator 215, a rotor 214, and a drive shaft 211 connected to or formed on the rotor 214. The drive shaft 211 rotates about a first axis 201. The rotor 214 of the motor 21 is coaxially fitted in the stator 215, that is, the motor 21 is an internal rotor motor.

[0093] 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 that meshes and rotates with the sun gear 221.

[0094] The stator 215 includes a stator core 2151, a stator winding 2152 wound on the stator core 2151, and a stator front end plate 2154 disposed at the front end of the stator core 2151. A through hole 2153 is provided on the stator core 2151, and the rotor 214 is disposed within the through hole. The rotor 214 includes a rotor body 2141 located 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 body 2141, and both ends of the drive shaft 211 pass through the rotor body 2141. The portion of the drive shaft 211 extending beyond the rear end of the rotor body 2141 is connected to a fan 217 used for cooling the motor 21. The drive shaft 211 passes through the rotor front end plate 2143, and the drive shaft 211 is fixedly connected to 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. In this embodiment, the sun gear 221 is disposed on the front end face 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 to or integrally formed with the drive shaft 211, or the sun gear 221 is fixedly connected to or integrally formed with the rotor front end plate 2143, or the sun gear 221, the drive shaft 211, and the rotor front end plate 2143 are fixedly connected or integrally formed. A motor front bearing 212 is provided on the portion of the drive shaft 211 that extends beyond the rotor front end plate 2143 for support. The motor front bearing 212 is disposed at the front end of the sun gear 221. In this embodiment, the sun gear 221 includes: a meshing tooth portion 2211 that meshes with the planetary gear set 222 and a connecting shaft 2214 disposed on the front side of the meshing tooth portion 2211. The connecting shaft 2214 rotates coaxially with the drive shaft 211, and the front bearing 212 of the motor is sleeved on the connecting shaft 2214.

[0095] Impact assembly 23 is used to output impact force. Impact assembly 23 includes a main shaft 231, an impact block 234 sleeved on the outer periphery of the main shaft 231, a hammer anvil 235 disposed 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 can slide back and forth relative to the main shaft 231 in the front-back direction. The spring 232 extends in the front-back direction and connects the main shaft 231 and the impact block 234 to realize the buffering effect during the impact process and to reset the impact block 234.

[0096] The planetary gear set 222 includes an internal gear ring 2221 and a plurality of planet gears 2222 meshing with the internal gear ring 2221. The internal gear ring 2221 meshes around the plurality of planet gears 2222. The internal gear ring 2221 is disposed on the stator 215. In this embodiment, the internal gear ring 2221 is disposed on the stator front end plate 2154, and the internal gear ring 2221 is fixedly connected to or integrally formed with the stator front end plate 2154. That is, the internal gear ring 2221 and the stator front end plate 2154 can be two separate components or integrally formed into a single component. Specifically, the stator front end plate 2154 has an internal gear structure formed on its inner side using powder metallurgy technology, forming the internal gear ring 2221 structure.

[0097] The planetary gear set 222 also includes multiple planetary pins 2223. Planetary gears 2222 are fitted onto and mesh with the planetary pins 2223. The planetary pins 2223 are 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 planetary pins 2223 are fixedly connected to the main shaft 231 using a cantilever beam fixing method. Each planetary gear 2222 is fitted onto one end of a planetary pin 2223 extending in the front-rear direction to transmit the power from the planetary gear 2222 to the planetary pin 2223. The sun gear 221 and the planetary gear set 222 form a meshing tooth portion 2211 for transmitting power. The addendum circle diameter of the sun gear 221 is set smaller than the addendum circle diameter of the planetary gear set 222, such that the number of meshing teeth in the planetary gear set 222 is greater than the number of teeth in the meshing tooth portion 2211 of the sun gear 221. The other end of the planetary pin 2223 is fixedly installed inside the main shaft 231 so that the main shaft 231 can rotate simultaneously with the planetary pin 2223.

[0098] In this embodiment, the internal gear ring 2221 and the stator 215 are structurally connected. More specifically, the internal gear ring 2221 and the stator 215 are integrally formed into a single component, shortening the axial length of the impact tool and making the internal structure of the impact tool more compact. Compared with the first embodiment, at least the wall thickness of the gearbox housing can be reduced; furthermore, the distance from the rear end face of the internal gear ring 2221 to the front end face of the stator 215 can be reduced, shortening the axial length by 6mm-11mm based on current product dimensions.

[0099] A first groove is formed on the main shaft 231, with the opening of the first groove facing the rear end. In this embodiment, the first groove is coaxial with the main shaft 231 and is circular. The motor front bearing 212 is embedded in the first groove. Specifically, the outer ring of the motor front bearing 212 abuts against the inner wall of the first groove, and the inner ring of the motor front bearing 212 abuts against the connecting shaft 2214 of the sun gear 221.

[0100] It is understood that this embodiment can also be applied to other power tools, such as handheld power tools like electric drills, impact drills, electric screwdrivers, grinding power tools (sanders, flat sanders, angle grinders), reciprocating saws, and multi-tools; outdoor power tools such as lawn mowers, lawn trimmers, and chainsaws, especially power tools that use planetary gears for rotary transmission.

[0101] like Figure 23 As shown, the third embodiment of this solution differs from the second embodiment in that the motor is directly connected to the impact assembly, eliminating the transmission assembly.

[0102] The motor 31 includes a stator 315, a rotor 314, and a drive shaft 311 connected to or formed on the rotor 314. The drive shaft 311 rotates about a first axis 301. In this embodiment, the rotor 314 of the motor 31 is coaxially fitted in the stator 315, meaning that the motor 31 is an internal rotor motor. The drive shaft 311 is directly connected to the main shaft 331 via a connector, meaning that the drive shaft 311 is directly connected to the main shaft 331. The rotational speed of the motor 31 is substantially the same as the rotational speed of the main shaft 331, and the output torque of the drive shaft 311 is substantially the same as the torque input to the main shaft 331. In other alternative embodiments, the motor 31 may be an external rotor motor, a brushed motor, or other motor structures. The motor 31 serves as a power source, and its structural form does not affect the protection scope of this embodiment.

[0103] The drive shaft 311 has an external spline 3111 at its front end, and the main shaft 331 has an internal spline 3311 structure that mates with it at its rear end. As an alternative embodiment, the front end of the drive shaft 311 and the rear end of the main shaft 331 are respectively provided with a mating pin connection structure, a flange connection structure, or a non-uniform shaft connection structure. Any connection structure that can achieve coaxiality and no transmission ratio between the drive shaft 311 and the main shaft 331 is within the scope of protection of this embodiment, and will not be described in detail here.

[0104] A spindle bearing 333 is provided at the rear end of the spindle 331. The spindle bearing 333 is located on the outside of the spindle 331. The spindle bearing 333 restricts the movement of the spindle 331 perpendicular to the first axis 301 and supports the front end of the drive shaft 311.

[0105] The impact tools described in the above embodiments, such as Figures 1 to 3As shown, the length L from the outer side wall 156 at the rear end of the housing to the front end of the hammer anvil 135, which is the axial length L of the impact tool, can be reduced. In the above embodiments, a portion of the technical solutions can be used alone, or a combination of several technical solutions can be used to shorten the axial length of the impact tool according to the actual needs of the impact tool. In currently available products, the overall axial length of the impact tool is 120mm, and its outer diameter is 61mm. However, the existing product size still cannot meet the customer's requirements for product miniaturization. Specifically, in the first embodiment of this application, the length L from the outer side wall 156 at the rear end of the housing to the front end of the hammer anvil 135 can be shorter than the prior art (120mm). For example, the length L is less than 114mm, further, less than 97mm, and even further, less than 90mm. After shortening the axial dimension of the motor, the length L from the outer side wall 156 at the rear end of the housing to the front end of the hammer anvil 135 is greater than or equal to 84mm and less than or equal to 86mm.

[0106] In the first embodiment of this application, the axial length of the transmission component, specifically, the length L1 from the rear end face of the gearbox housing 123 to the front end of the hammer anvil 135, is shortened. For example, the length L1 is less than 74 mm, further, the length L1 is less than 66 mm, and even further, in order to ensure that the output impact force meets the usage standard, L1 is greater than or equal to 59 mm and less than or equal to 66 mm.

[0107] The outer diameter D of the outer casing 15 can be smaller than that of the prior art (61 mm). When the length L from the outer side wall 156 at the rear end of the outer casing to the front end of the anvil 135 is less than or equal to 97 mm and greater than or equal to 84 mm, the outer diameter D of the outer casing 15 is less than or equal to 60 mm. Further, the outer diameter D of the outer casing 15 is less than or equal to 58 mm, and the outer diameter D of the outer casing is greater than or equal to 56 mm.

[0108] In the second embodiment of this application, the length L from the outer side wall 156 at the rear end of the housing to the front end of the hammer anvil 135 is further shortened than the length in the first embodiment, and L is greater than or equal to 78 mm and less than or equal to 80 mm.

[0109] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. An impact tool, comprising: shell; An electric motor, housed in the housing, the electric motor including or connected to a drive shaft for outputting power and rotating about a first axis; An impact assembly for providing impact force includes a main shaft driven by the drive shaft, an impact block sleeved on the main shaft, and a hammer anvil disposed at the front end of the impact block; the main shaft rotates about the main shaft axis; the impact block includes an impact block body and end teeth that cooperate with the hammer anvil; Its features are, The impact assembly also includes: A rolling ball spans the first ball groove provided on the impact block and the second ball groove provided on the main shaft, thereby connecting the impact block and the main shaft; The impact block slides back and forth relative to the main shaft along the axis of the main shaft with a predetermined stroke; the impact block includes a first position where it moves backward to the farthest end and a second position where it moves forward to the farthest end; when the impact block moves between the first position and the second position, the second ball groove is always located behind the front end face of the impact block body; The axial length of the impact tool is less than 114 mm.

2. The impact tool according to claim 1, characterized in that, The impact assembly further includes: an elastic element that provides a force to the impact block to bring it closer to the anvil; the two ends of the elastic element are respectively connected to the main shaft and the impact block; the main shaft includes a plane for abutting the elastic element, and when the impact block is in the first position, the rear end face of the impact block at least partially engages with the plane.

3. The impact tool according to claim 1, characterized in that, The second position of the impact block is locked onto the hammer anvil.

4. The impact tool according to claim 1, characterized in that, The main shaft rotates coaxially with the drive shaft, and the first axis coincides with the axis of the main shaft.

5. The impact tool according to claim 4, characterized in that, The first ball groove is disposed on the front end face of the impact block and extends rearward along the first axis; the second ball groove is disposed on the outer surface of the main shaft and extends radially inward along the main shaft.

6. The impact tool according to claim 2, characterized in that, The diameter of the end of the elastic element connected to the main shaft is smaller than the diameter of the end of the elastic element connected to the impact block.

7. The impact tool according to claim 1, characterized in that, The impact block body is provided with a ball mounting groove; the ball mounting groove guides the ball into the first ball groove and the second ball groove; the ball mounting groove includes a second opening for the ball to leave the ball mounting groove; the vertical distance from the rear end of the second opening to the front end face of the impact block body is L3; the vertical distance from the rear end of the first ball groove to the front end face of the impact block body is L4; the diameter of the ball is D1, where 0.5+D1≤L4-L3≤1.5D1.

8. The impact tool according to claim 7, characterized in that, The ball mounting groove is disposed at the front end of the first ball groove, and the ball mounting groove further includes a first opening formed on the front end face of the impact block body.

9. The impact tool according to claim 7, characterized in that, When the impact block is in the second position, the rolling ball is located at the rear end of the first ball groove.

10. The impact tool according to claim 2, characterized in that, The impact block forms an annular groove with an opening facing the motor at its rear end, and at least part of the elastic element is disposed in the annular groove; when the impact block moves to the first position, the rear end face of the annular groove abuts against the plane of the main shaft used to abut the elastic element.

11. An impact tool, comprising: shell; An electric motor, housed in the housing, the electric motor including or connected to a drive shaft for outputting power and rotating about a first axis; An impact assembly for providing impact force includes a main shaft driven by the drive shaft, an impact block sleeved on the main shaft, and a hammer anvil disposed at the front end of the impact block; the main shaft rotates about the main shaft axis; the impact block includes an impact block body and end teeth that cooperate with the hammer anvil; Its features are, The impact assembly also includes: A rolling ball spans the first ball groove provided on the impact block and the second ball groove provided on the main shaft, thereby connecting the impact block and the main shaft; The impact block slides back and forth relative to the main shaft along the axis of the main shaft with a predetermined stroke; the impact block includes a first position where it moves backward to the farthest end and a second position where it moves forward to the farthest end. The impact block body is provided with a ball mounting groove; the ball mounting groove extends rearward from the front end of the impact block body; the ball mounting groove guides the ball into the first ball groove and the second ball groove; the ball mounting groove includes a second opening for the ball to leave the ball mounting groove; the vertical distance from the rear end of the second opening to the front end of the impact block body is L3; the vertical distance from the rear end of the first ball groove to the front end of the impact block body is L4; the diameter of the ball is D1, where D1+0.5≤L4-L3≤1.5D1.

Images