Electric tool

Abstract

The invention discloses an electric tool, which comprises a chuck main body, a clamping head, a driving device and a driving device, and is characterized in that the chuck main body comprises a clamping jaw for clamping a workpiece; the output shaft is used for transmitting torque to enable the chuck body to rotate, the output shaft and the chuck body are limited in the radial direction through a connecting hole, and an axial connecting groove is formed in the end, inserted into the chuck body, of the output shaft; the axial limiting piece is located in the chuck main body, and the axial limiting piece is connected with the chuck main body and the axial connecting groove; the axial limiting piece is in direct or indirect contact with the elastic piece or the anti-loosening material so that the pre-tightening force between the axial limiting piece and the axial connecting groove can be increased. By the adoption of the technical scheme, the electric tool with the chuck good in connection tightness can be provided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tools, in particular to an electric tool. BACKGROUND

[0002] Electric tools are more environmentally friendly than engine tools, and thus are widely used. Electric tools generally use motors to drive work. Rotating electric tools generally refer to rotating work heads driven by motors to achieve functions, such as electric drills or electric screwdrivers. The existing chuck structure of the electric tool is prone to chuck connection loosening when the electric tool continuously works.

[0003] This part provides background information related to the present application, which may not be prior art. SUMMARY

[0004] One object of the present application is to solve or at least alleviate part or all of the above problems. To this end, one object of the present application is to provide an electric tool with good chuck connection tightness.

[0005] To achieve the above object, the present application adopts the following technical solution:

[0006] An electric tool, comprising: a chuck body comprising a chuck jaw for clamping a workpiece; an output shaft for transmitting torque to rotate the chuck body, the output shaft being radially limited by a connecting hole of the chuck body, and an axial connecting groove being provided at one end of the output shaft inserted into the chuck body; an axial limiting member located inside the chuck body, the axial limiting member connecting the chuck body and the axial connecting groove; and an elastic member or a locking material directly or indirectly contacting the axial limiting member to increase the pre-tightening force between the axial limiting member and the axial connecting groove.

[0007] In some embodiments, the axial limiting member is a screw.

[0008] In some embodiments, the axial contact part of the axial limiting member and the axial connecting groove is provided with a locking material.

[0009] In some embodiments, the locking material is a Nello glue or anaerobic glue.

[0010] In some embodiments, the elastic member is arranged between the nut of the screw and the chuck body.

[0011] In some embodiments, the elastic member is a spring piece.

[0012] In some embodiments, the elastic member is arranged between the end of the screw rod and the axial connecting groove.

[0013] In some embodiments, the elastic member is a spring.

[0014] In some embodiments, the highest rotating speed of the chuck body is greater than or equal to 2800 rpm.

[0015] In some embodiments, the electric tool further comprises a PCB box, and a side of the PCB box is provided with a wire clamping groove.

[0016] The application has the beneficial effects that: by setting the axial limiting piece connected with the chuck body and the output shaft in contact with the elastic piece or the anti-loosening material, the pre-tightening force between the axial limiting piece and the axial connecting groove of the chuck body and the output shaft is increased, so that the tightness of the chuck connection is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a side view of the hand-held electric tool in

[0018] Figure 2 is Figure 1 is a sectional view of the hand-held electric tool in

[0019] Figure 3 is Figure 1 is a sectional view of the hand-held electric tool in

[0020] Figure 4 is Figure 1 is a sectional view of the hand-held electric tool in

[0021] Figure 5 is Figure 1 is an exploded view of the multi-stage planetary transmission group of the hand-held electric tool in

[0022] Figure 6 is Figure 1 is a side view of the hand-held electric tool in

[0023] Figure 7 is a side view of the hand-held electric tool in Figure 3 high speed gear;

[0024] Figure 8 is a side view of the hand-held electric tool in Figure 4 low speed gear;

[0025] Figure 9 is Figure 1 is a circuit block diagram of the hand-held electric tool in

[0026] Figure 10 is Figure 1 is a signal processing module of the controller of the hand-held electric tool in

[0027] Figure 11 is Figure 1Control method flow chart of the handheld power tool in

[0028] Figure 12 is Figure 1 Handheld power tool in includes cross-sectional view of detection element

[0029] Figure 13 is Figure 9 Motor conduction angle 120 degrees in is a schematic diagram

[0030] Figure 14 is Figure 9 Motor conduction angle 150 degrees in is a schematic diagram

[0031] Figure 15 Clamping mechanism of handheld power tool in an embodiment includes cross-sectional view of anti-loosening material

[0032] Figure 16 Clamping mechanism of handheld power tool in an embodiment includes cross-sectional view of clamping portion

[0033] Figure 17 is Figure 16 Clamping mechanism in includes another perspective view of the cross-sectional view of the clamping portion

[0034] Figure 18 Clamping mechanism of handheld power tool in an embodiment includes cross-sectional view of elastic sheet

[0035] Figure 19 Clamping mechanism of handheld power tool in an embodiment includes cross-sectional view of spring

[0036] Figure 20 is Figure 1 PCB box in handheld power tool in is a perspective view DETAILED DESCRIPTION

[0037] Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above-described accompanying drawings.

[0038] In this application, the terms "including", "containing", "having" or any other similar words are intended to cover a non-exclusive inclusion, so that a process, method, article or device including a series of elements does not only include those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or device. Without more limitations, the element defined by the phrase "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0039] In the present application, the term "and / or", is a description of an associated relationship with associated objects, which means that there can be three kinds of relationships. For example, A and / or B, can represent: the existence of A alone, the existence of A and B together, and the existence of B alone. In addition, the character " / " in the present application generally indicates that the front and rear associated objects are in a "and / or" relationship.

[0040] In the present application, the terms "connected", "combined", "coupled", "mounted" can be direct connection, combination, coupling or mounting, or indirect connection, combination, coupling or mounting. Among them, for example, direct connection refers to the connection of two parts or components without the need for an intermediate part, while indirect connection refers to the connection of two parts or components with at least one intermediate part. In addition, "connection" and "coupling" are not limited to physical or mechanical connection or coupling, and can include electrical connection or coupling.

[0041] In the present application, those of ordinary skill in the art will understand that the relative terms used in connection with quantities or conditions (for example, "about", "approximately", "substantially" and the like) include the values described and have the meaning indicated by the context. For example, the relative terms at least include the degree of error related to the measurement of a specific value, the tolerance caused by manufacturing, assembly, use, etc. related to a specific value. Such terms should also be considered to disclose the range defined by the absolute values of the two endpoints. The relative term can refer to a certain percentage (for example, 1%, 5%, 10% or more) of the indicated value. The numerical value without the relative term should also be disclosed as a specific value with a tolerance. In addition, "substantially" when expressing the relative angular positional relationship (for example, substantially parallel, substantially perpendicular), can refer to a certain number of degrees (for example, 1 degree, 5 degrees, 10 degrees or more) added or subtracted from the indicated angle.

[0042] In the present application, those of ordinary skill in the art will understand that the functions performed by the components can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by the parts can also be performed by one part, one component, or multiple parts in combination.

[0043] In this application, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when an element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent positive orientation but can also be understood as lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0044] In this application, the terms "controller," "processor," "central processing unit," "CPU," and "MCU" are used interchangeably. When using the unit "controller," "processor," "central processing unit," "CPU," or "MCU" to perform a specific function, unless otherwise stated, these functions may be performed by a single or multiple of the aforementioned units.

[0045] In this application, the terms "device," "module," or "unit" are used to describe devices that can be implemented in hardware or software to perform a specific function.

[0046] In this application, the terms “calculation,” “judgment,” “control,” “determine,” “identify,” etc., refer to the operation and process of a computer system or similar electronic computing device (e.g., controller, processor, etc.).

[0047] The power tools applicable to the technical solution of this application are specifically described using handheld power tools as an example.

[0048] like Figure 1 As shown, this application provides a handheld power tool 100. In this embodiment, the handheld power tool 100 can be an electric drill. The handheld power tool 100 includes a power supply device 200. The power supply device 200 provides electrical energy to the handheld power tool 100. In this embodiment, the power supply device 200 can be a battery pack, which, in conjunction with a corresponding power circuit, supplies power to the corresponding components within the handheld power tool 100. Those skilled in the art should understand that the power supply device 200 is not limited to scenarios using a battery pack; it can also supply power to the corresponding components within the handheld power tool 100 through mains power or AC power, in conjunction with corresponding rectification, filtering, and voltage regulation circuits. For ease of subsequent description, this application uses "battery pack 200" to represent the power supply device 200.

[0049] like Figure 1 and Figure 2As shown, the handheld power tool 100 includes a housing 110, a motor 120, a transmission mechanism 130, and an output mechanism 140. The motor 120 includes a stator and a rotor. The housing 110 includes a motor housing 111 for accommodating the motor 120 and an output housing 112 for accommodating at least part of the output mechanism 140, the output housing 112 being connected to a front end of the motor housing 111. The housing 110 further forms or is connected with a grip 113 for a user to operate. The grip 113 forms a T-shaped or L-shaped structure with the motor housing 111, facilitating the user to hold and operate. In some embodiments, the grip 113 forms a straight cylinder structure with the motor housing 111. The housing 110 forms or is connected with a battery pack interface 210 for mounting a battery pack 200. The battery pack interface 210 is arranged at one end of the grip 113, and the battery pack 200 supplies power to the handheld power tool 100 through the battery pack interface 210. In the present embodiment, the battery pack 200 is detachably connected to the grip 113. In some alternative embodiments, the battery pack 200 is built-in in the housing.

[0050] The handheld power tool 100 further includes a main switch 150 mounted on the grip 113. The user can conveniently trigger the main switch 150 when holding the grip 113, and the main switch 150 can be arranged as a switch for starting the handheld power tool 100.

[0051] The motor 120, the transmission mechanism 130, and the output mechanism 140 are arranged in sequence along a front-rear direction in the motor housing 111 and the output housing 112. The motor 120 includes a motor drive shaft 121 rotatable about a drive axis 101.

[0052] The output mechanism 140 is configured to receive torque provided by the motor 120 and output torque. The output mechanism 140 includes an output shaft 141 for connecting and mounting a work head and driving the work head to rotate. The motor 120 drives the output shaft 141 to rotate about an output axis 102. The motor 120 drives the work head to rotate via the transmission mechanism 130 and the output shaft 141. The output shaft 141 is provided with a clamping mechanism 160 or a receiving portion at a front end, which can clamp a corresponding work head, such as a screwdriver bit, a drill bit, a sleeve, etc., when different functions are implemented.

[0053] The output shaft 141 is configured to output torque, and the output shaft 141 rotates about the output axis 102. In the present embodiment, the output axis 102 coincides with the drive axis 101. In other alternative embodiments, the output axis 102 is arranged at an angle with the drive axis 101. In other alternative embodiments, the output axis 102 is parallel to the drive axis 101 but not coincident with the drive axis 101.

[0054] The transmission mechanism 130 is disposed between the motor 120 and the output mechanism 140, and is used to transmit power between the motor 120 and the output mechanism 140. Specifically, the transmission mechanism 130 is disposed between the rotor of the motor 120 and the output shaft 141 of the output mechanism 140.

[0055] The transmission mechanism 130 includes a multi-stage transmission group. In this embodiment, the multi-stage transmission group is a multi-stage planetary transmission group 300. The planetary transmission group includes a planetary gear, a planetary carrier for mounting the planetary gear, and an internal gear ring meshing with the planetary gear. At least one stage of the multi-stage planetary transmission group 300 has an adjustable transmission ratio, and the output transmission ratio of the multi-stage planetary transmission group 300 is greater than 1. The planetary carrier in the planetary transmission group closest to the output mechanism 140 in the multi-stage planetary transmission group 300 is formed on or connected to the output shaft 141. In this embodiment, the internal gear ring of at least one stage of the planetary transmission group is configured to move between a first position and a second position. By setting up a multi-stage planetary transmission group and then adjusting the transmission ratio of the planetary gears to achieve speed regulation and thus torque regulation, it is equivalent to adding a mechanical means to regulate speed and torque. In this embodiment, the adjustable transmission ratio of the planetary transmission group means that the planetary transmission group has at least two different transmission ratios, one of which corresponds to the first speed gear of the handheld power tool 100, and the other transmission ratio corresponds to the second speed gear of the handheld power tool 100. The first speed gear is a high speed gear, and the second speed gear is a low speed gear.

[0056] In some embodiments, the transmission mechanism 130 has two transmission states that cause the output shaft 141 to output at different speeds. For example... Figure 2 and Figure 3 As shown, the transmission mechanism 130 includes a housing assembly 1301 and a multi-stage planetary transmission group 300, which includes a first-stage planetary gear group 310, a second-stage planetary gear group 320, and a third-stage planetary gear group 330.

[0057] like Figure 3 and Figure 4 As shown, the first-stage planetary gear set 310 and the second-stage planetary gear set 320 are at least partially located within the housing assembly 1301. The first-stage planetary gear set 310 is located near the motor shaft 121, and the third-stage planetary gear set 330 is located near the output shaft 141. Optionally, the first-stage planetary gear set 310 and the third-stage planetary gear set 330 output with only one gear ratio. That is, the gear ratios of both the first-stage planetary gear set 310 and the third-stage planetary gear set 330 are greater than 1. In other words, the first-stage planetary gear set 310 and the third-stage planetary gear set 330 perform a deceleration and torque increase operation, where the output speed is less than the input speed of the planetary gear set, and the output torque is greater than the input torque of the planetary gear set.

[0058] The first-stage planetary gear set 310 includes: a first planetary gear 311, a first planetary gear carrier 312 for mounting the first planetary gear 311, and a first internal gear ring 313 meshing with the first planetary gear 311. The motor shaft 121 forms with or connects to the first sun gear 122. Optionally, the first sun gear 122 rotates coaxially with the motor shaft 121. Specifically, the first sun gear 122 rotates about the drive shaft 101. Optionally, the first sun gear 122 is connected to the motor shaft 121. Optionally, as... Figure 3 and Figure 4 As shown, the housing assembly 1301 includes at least one protrusion 1301a, and the first internal gear ring 313 includes at least one groove 313a that matches the protrusion 1301a. By providing the protrusion 1301a and the groove 313a, the first internal gear ring can be fixed in the housing assembly 1301, that is, the first stage planetary gear set 310 can be fixed in the housing assembly 1301.

[0059] The first sun gear 122 drives the first planetary gear 311. The first planetary gear 311 is configured to mesh with the first sun gear 122. Multiple first planetary gears 311 are provided, and all of the multiple first planetary gears 311 are configured to mesh with the first sun gear 122. In some embodiments, such as Figure 5 As shown, four first planetary gears 1441 are evenly arranged circumferentially around the drive axis 101. The first sun gear 122 and the first planetary gears 311 form a meshing tooth section for transmitting power. Since the transmission ratio corresponding to the first-stage planetary gear set 310 is greater than 1, the number of teeth in the meshing teeth of the first-stage planetary gear set 310 is greater than the number of teeth in the meshing tooth section of the sun gear. The first internal gear ring 313 meshes around the periphery of the plurality of first planetary gears 311. The first planetary gear carrier 312 includes a first transmission disk 3121, a first support frame 3122, and a first output section. The first support frame 3122 and the first output section are respectively formed on both sides of the first transmission disk 3121, and the first output section rotates synchronously with the first transmission disk 3121. The first support frame 3122 is inserted into the first planetary gear 311 and forms a rotatable connection with the first planetary gear 311, so that the first planetary gear 311 can drive the first planetary gear carrier 312 to rotate around the drive axis 101. The first output section has meshing teeth formed on its peripheral side. The first output section is used to mesh with the second-stage planetary gear set 320, thereby realizing the transmission connection between the first-stage planetary gear set 310 and the second-stage planetary gear set 320. Optionally, the first output section is the second sun gear 3201 of the second-stage planetary gear set 320.

[0060] The second-stage planetary gear set 320 includes: a second planetary gear 321, a second planetary gear carrier 322 for mounting the second planetary gear 321, and a second internal gear ring 323 meshing with the second planetary gear 321. The second sun gear 3201 drives the second planetary gear 321. Optionally, the second sun gear 3201 rotates coaxially with the motor shaft 121; specifically, the second sun gear 3201 rotates about the drive axis 101. The second planetary gear 321 is configured to mesh with the second sun gear 3201. Multiple second planetary gears 321 are provided, and all of the multiple second planetary gears 321 are configured to mesh with the second sun gear 3201. In this embodiment, as... Figure 5 As shown, four second planetary gears 321 are evenly arranged circumferentially around the drive axis 101. The meshing relationship between the second planetary gears 321, the second planetary carrier 322, and the second internal gear ring 323 is the same as that in the first-stage planetary gear set 310, which is well known to those skilled in the art and will not be described in detail here. Specifically, the outer ring of the second planetary carrier 322 is provided with gears that mesh with the second internal gear ring 323, enabling the second-stage planetary gear set 320 to switch between a transmission state and a speed-changing state. The transmission state and the speed-changing state correspond to the first position and the second position of the second-stage planetary gear set 320, respectively.

[0061] The second planetary gear carrier 322 includes a second transmission disk 3221, a second support frame 3222, and a second output section. The second output section is snap-fitted to the second transmission disk 3221. The second support frame 3222 and the second output section are respectively formed on both sides of the second transmission disk 3221, and the second output section rotates synchronously with the second transmission disk 3221. The second support frame 3222 is inserted into the second planetary gear 321 and forms a rotatable connection with the second planetary gear 321, so that the second planetary gear 321 can drive the second planetary gear carrier 322 to rotate around the drive axis 101. The second output section has meshing teeth formed on its periphery, and the second output section is used to mesh with the third-stage planetary gear set 330, thereby realizing the transmission connection between the second-stage planetary gear set 320 and the third-stage planetary gear set 330. Optionally, the second output section is the third sun gear 3301 of the third-stage planetary gear set 330.

[0062] The third-stage planetary gear set 330 includes: a third planetary gear 331, a third planetary gear carrier 332 for mounting the third planetary gear 331, and a third internal gear ring 333 meshing with the third planetary gear 331. The third sun gear 3301 drives the third planetary gear 331. Optionally, the third sun gear 3301 rotates coaxially with the motor shaft 121; specifically, the third sun gear 3301 rotates about the drive axis 101. The third planetary gear 331 is configured to mesh with the third sun gear 3301. Multiple third planetary gears 331 are provided, and all of the multiple third planetary gears 331 are configured to mesh with the third sun gear 3301. In this embodiment, as...Figure 5 As shown, six third planetary gears 331 are evenly arranged around the circumference of the driving axis 101. The engagement relationship among the third planetary gears 331, the third planetary carrier 332 and the third inner ring gear 333 is the same as that in the first planetary gear set 310, which is well known to those skilled in the art and will not be described here.

[0063] The third planetary carrier 332 comprises a third transmission disc 3321 and a third support frame 3322, the third support frame 3322 is inserted into the third planetary gear 331 and rotatably connected with the third planetary gear 331, so that the third planetary gear 331 can drive the third transmission disc 3321 to rotate around the driving axis 101.

[0064] Optionally, as shown in Figure 3 and Figure 4 , the third transmission disc 3321 is formed on the rear end of the output shaft 141. The third planetary gear 331 drives the output shaft 141 to rotate through the third planetary carrier 332. Optionally, the third transmission disc 3321 and the output shaft 141 can be independent components, and the third transmission disc 3321 is connected to the output shaft 141 as long as it can drive the output shaft 141 to rotate.

[0065] As shown in Figures 1-2 , the handheld power tool 100 further comprises a switching mechanism 170 for driving the transmission mechanism 130 to switch between different transmission states. The switching mechanism 170 comprises an operating member 172 for user operation. As shown in Figures 3-6 , the switching mechanism 170 comprises a shifting frame. The operating member 172 drives the shifting frame to displace. Optionally, the shifting frame comprises a first shifting frame 171 for driving the second inner ring gear 323, and the first shifting frame 171 is connected with the second inner ring gear 323.

[0066] When the second planetary gear set 320 needs to be in the transmission state, that is, the second planetary gear set 320 does not perform the speed reduction operation, at this time it corresponds to the first speed gear of the handheld power tool 100, which is the high speed gear. As shown in Figure 3 and Figure 6 , the first shifting frame 171 is operated to drive the second inner ring gear 323 to move forward along the driving axis 101, specifically to the direction of the third planetary carrier 330, until the second inner ring gear 323 is simultaneously clamped in the second planetary gear 321 and the second planetary carrier 322, and the second inner ring gear 323 is not fixed in the housing assembly 1301, then the meshing teeth of the second inner ring gear 323 and the second planetary gear 321 and the second planetary carrier 322 are engaged and synchronously rotated. It is equivalent to synchronously rotating the second inner ring gear 323 with the second sun gear 3201 and the second planetary carrier 322, and there is no speed reduction process, and the transmission ratio of the second planetary gear set 320 is 1.

[0067] When the second-stage planetary gear set 320 needs to be in a shifting state, that is, when the second-stage planetary gear set 320 performs a deceleration operation, this corresponds to the low-speed second gear of the handheld power tool 100. For example... Figure 4 and Figure 6 As shown, the first gear 171 is operated to drive the second internal gear ring 323 to move backward along the drive axis 101, specifically towards the first planetary gear carrier 310. The second internal gear ring 323 is engaged with the first internal gear ring 313. Since the first internal gear ring 313 is fixed to the housing assembly 1301 and cannot rotate, the second internal gear ring 323 also cannot rotate at this time. Therefore, the rotation of the second planetary gear 321 will not drive the second internal gear ring 323 to rotate. The second planetary gear set 320 performs a deceleration operation by rotating the second sun gear 3201 to drive the second planetary gear 321 to rotate. The transmission ratio of the second-stage planetary gear set 320 is greater than 1.

[0068] In some embodiments, Figure 7 To and Figure 3 A diagram showing the corresponding handheld power tool 100 in high-speed mode. (See diagram for example.) Figure 7 As shown, when the handheld power tool 100 is in high-speed mode, i.e., when the second-stage planetary gear set 320 is in transmission mode, the transmission mechanism 130 is a two-stage reduction mechanism, including a first-stage reduction mechanism 131 and a second-stage reduction mechanism 132. The first-stage reduction mechanism 131 includes a first planetary gear set 310, a first sun gear 122, a second planetary gear set 320, and a second sun gear 3201. The second-stage reduction mechanism 132 includes a third planetary gear set 330 and a third sun gear 3301. At this time, the transmission ratio of the first-stage reduction mechanism 131 is the same as the transmission ratio of the first planetary gear set 310, and the transmission ratio of the second-stage reduction mechanism 132 is the same as the transmission ratio of the third planetary gear set 330. This reduces the speed of the motor 120 twice, driving the working head to rotate.

[0069] In some embodiments, Figure 8 To and Figure 4 The diagram shows the corresponding handheld power tool 100 in low speed mode. (See diagram for example.) Figure 8As shown, when the handheld electric tool 100 is in the low-speed gear, i.e., the second planetary gear set 320 is in the gear shifting state, the transmission mechanism 130 is a three-stage speed reduction mechanism, including a first-stage speed reduction mechanism 133, a second-stage speed reduction mechanism 134, and a third-stage speed reduction mechanism 135. The first-stage speed reduction mechanism 133 includes the first planetary gear set 310 and the first sun gear 122, the second-stage speed reduction mechanism 134 includes the second planetary gear set 320 and the second sun gear 3201, and the third-stage speed reduction mechanism 135 includes the third planetary gear set 330 and the third sun gear 3301. At this time, the transmission ratio of the first-stage speed reduction mechanism 133 is the transmission ratio of the first planetary gear set 310, the transmission ratio of the second-stage speed reduction mechanism 134 is the transmission ratio of the second planetary gear set 320, and the transmission ratio of the third-stage speed reduction mechanism 135 is the transmission ratio of the third planetary gear set 330. At this time, the speed of the motor 120 is reduced three times to drive the working head to rotate.

[0070] In some embodiments, the low-speed ratio of the transmission mechanism 130 is less than or equal to 15, and the high-speed ratio of the transmission mechanism is greater than or equal to 45. The low-speed ratio and the high-speed ratio of the transmission mechanism 130 are achieved by the multi-stage planetary gear set 300 and the corresponding sun gears. The speed ratio of the transmission mechanism 130 refers to the ratio of the speed of the motor 120 to the speed of the working head. The low-speed ratio corresponds to the ratio of the speed of the motor 120 to the speed of the working head when the handheld electric tool 100 is in the high-speed gear, and the transmission mechanism 130 is a two-stage speed reduction mechanism. The high-speed ratio corresponds to the ratio of the speed of the motor 120 to the speed of the working head when the handheld electric tool 100 is in the low-speed gear, and the transmission mechanism 130 is a three-stage speed reduction mechanism. That is, when the speed of the motor 120 is constant, the speed of the working head corresponding to the low-speed ratio is higher, and the speed of the working head corresponding to the high-speed ratio is lower. Optionally, the low-speed ratio of the transmission mechanism 130 can be 12.32. Optionally, the low-speed ratio of the transmission mechanism 130 can be 13. Optionally, the high-speed ratio of the transmission mechanism 130 can be 51.

[0071] In some embodiments, for example, when the low-speed ratio of the transmission mechanism 130 is 12.32, i.e., when the handheld electric tool 100 is in the high-speed gear. The speed of the motor 120 is set to 28000 rpm, and the corresponding speed of the working head is about 2272 rpm.

[0072] In some embodiments, the diameter of the motor 120 is greater than 50 mm. That is, the motor 120 in the present application is a relatively large-sized motor, and when the motor 120 is in an idle state, the speed of the motor 120 (i.e., the maximum speed of the motor 120) is also not too high. However, the speed of the large-sized motor will not decrease too much when there is a load. Optionally, when the torque of the electric drill 120 is greater than or equal to 6 Nm and less than or equal to 8 Nm, the speed of the electric drill 120 will not decrease too much due to the large size of the electric drill 120, so that the speed of the electric drill 120 can be maintained at 2000 rpm.

[0073] In some embodiments, the battery pack 200 is a soft pack battery pack, and the voltage of the battery pack 200 is greater than or equal to 20V. Optionally, the voltage of the battery pack 200 is 24V. Since the battery pack 200 is a soft pack battery pack, the internal resistance of the battery pack 200 is small, the voltage drop is small, and the discharge capacity is strong.

[0074] In some embodiments, since the size of the motor 120 is large, the maximum speed is not too large, and the low speed ratio of the transmission mechanism 130 is limited by the multi-stage planetary transmission set 300 and the corresponding sun gear, in order to make the speed of the output of the working head of the handheld electric tool 100 higher, the FOC field weakening control can be used for the motor 120 to improve the maximum speed of the motor 120, specifically, the controller 420 implements the FOC field weakening control on the motor 120.

[0075] Reference Figure 9 The circuit block diagram of the handheld electric tool 100 shown in the figure, the driving system of the motor 120 can at least include a power supply 200 (i.e. a battery pack 200), a control circuit 400, which can include a driving circuit 410, a controller 420.

[0076] In this embodiment, the motor 120 is an inner rotor brushless motor. In other alternative embodiments, the motor 120 is an outer rotor brushless motor. In this embodiment, the brushless motor is set as a three-phase brushless motor. It can be understood that the motor is not limited to a three-phase brushless motor, but can also be other types of direct current motors, and the above does not affect the substantial content of the present application. The motor 120 at least includes three-phase stator windings A, B, C, which can be star-connected or delta-connected.

[0077] The driving circuit 410 is electrically connected with the stator windings A, B, C of the motor 120, for transmitting the current from the battery pack 200 to the stator windings A, B, C to drive the motor 120 to rotate. In one embodiment, the driving circuit 410 includes a plurality of switching elements Q1, Q2, Q3, Q4, Q5, Q6, which are arranged on the current path from the battery pack 200 to the motor 120. Among them, Q1, Q3, Q5 are high-side switching elements, and Q2, Q4, Q6 are low-side switching elements. Any one phase stator winding of the motor 120 is connected with a high-side switching element and a low-side switching element.

[0078] The gate terminal of each of the switching elements in the drive circuit 410 is electrically connected to the controller 420 for receiving a control signal from the controller 420, which can be a PWM signal. The controller 420 can output the control signal to control the switching elements in the drive circuit 410 to turn on to regulate the power supply from the battery pack 200 to the motor 120. The drain or source of each of the switching elements is connected to the stator windings A, B, C of the motor 120. The switching elements Q1-Q6 receive the control signal from the controller 420 to change their respective on / off states, thereby changing the current supplied by the power source 200 to the stator windings A, B, C of the motor 120. In one embodiment, the drive circuit 410 can be a three-phase bridge driver circuit including six controllable semiconductor power devices (e.g. FET, BJT, IGBT, etc.). It can be appreciated that the switching elements described above can also be any other type of solid state switch, such as an insulated gate bipolar transistor (IGBT), a bipolar junction transistor (BJT), etc.

[0079] To drive Figure 9 the motor 120 to rotate, the drive circuit 410 has a plurality of drive states, and in different drive states, the motor 120 can have different rotational speeds or directions. The present application does not describe in detail the process of the controller 420 controlling the drive circuit 410 to change the different drive states to make the motor 120 obtain different rotational speeds or directions.

[0080] In combination Figure 10 and Figure 11 , the process of the controller 420 implementing FOC field weakening control on the motor 120 includes the following steps:

[0081] S111: obtaining motor sampling current and target speed of the motor;

[0082] The controller 420 obtains the motor sampling current signal of the motor 120, which can be the bus current or the phase current. After obtaining the motor sampling current signal, the controller 420 obtains the motor sampling current by calculation. Specifically, the current calculation unit 511 calculates the current three-phase current of the motor 120. The target speed of the motor 120 is obtained from the target speed setting unit 521, and the value is set by the user.

[0083] S112: current coordinate transformation;

[0084] After the current calculation unit 511 calculates the three-phase current, it is transmitted to the coordinate transformation unit for current coordinate transformation, so as to obtain the first feedback current Iq and the second feedback current Id.

[0085] As an option, the coordinate transformation unit comprises a first coordinate transformation unit 512, which can be used to transform the three-phase alternating current calculated by the current calculation unit 511 into two-phase alternating current; and a second coordinate transformation unit 513, which is used to transform the two-phase alternating current obtained by the first coordinate transformation unit 512 into two-phase direct current, which are respectively the first feedback current Iq and the second feedback current Id.

[0086] As an option, the first coordinate transformation unit 512 adopts clark transformation, and the second coordinate transformation unit 513 adopts Park transformation.

[0087] S113: obtaining the first feedback current Iq and the second feedback current Id;

[0088] Through the coordinate transformation unit, the controller 420 can obtain two feedback currents, the first feedback current Iq and the second feedback current Id. The first feedback current Iq and the second feedback current Id are perpendicular to each other. In this way, the signal processing module in the controller 420 obtains the first feedback current Iq and the second feedback current Id according to the sampling current of the motor 120, wherein the first feedback current Iq is the torque current, which is related to the motor torque, and the second feedback current Id is the excitation current, which is related to the stator magnetic field strength.

[0089] S114: obtaining the current speed and position of the motor;

[0090] The speed and position estimation unit 514 obtains the current speed ω and / or rotor position of the motor 120 through calculation according to the obtained motor sampling current and some parameters obtained in the coordinate transformation process.

[0091] S115: obtaining the first target current Iq* and the second target current Id*;

[0092] The first target current Iq* and the second target current Id* can be determined by calculation or given directly. The first target current Iq* is the excitation current, which is used to control the torque, generate the torque perpendicular to the rotor, and maximize the driving of the rotor rotation. The second target current Id* is the torque current, which is used to control the magnetic field strength.

[0093] In some embodiments, the first target current Iq* is obtained as follows: the speed comparison and adjustment unit 515 compares and adjusts the obtained current speed ω of the motor with the set target speed ω*, to generate the first target current Iq* which can be used to control the motor speed to reach the target speed ω* as quickly and stably as possible, the principle of which is to control the torque by using the torque current to enable the rotor to rotate to the maximum extent. Alternatively, the speed comparison and adjustment unit 515 includes a PI regulator, and the speed comparison and adjustment unit 515 adjusts the first target current Iq* in a PI adjustment manner according to the comparison result of the current speed ω of the motor 120 and the target speed ω*.

[0094] The first target current Iq* can control the torque, and the second target current Id* can control the strength of the magnetic field. In order to improve the overall efficiency and torque, the first target current Iq* should be as large as possible. Since the first target current Iq* and the second target current Id* are actually decoupled from the actual motor current, if the first target current Iq* is to be as large as possible, the second target current Id* should be as small as possible, so Id*=0.

[0095] S116: Obtain the first target voltage Vq and the second target voltage Vd;

[0096] The first current comparison and adjustment unit 516 obtains the first target voltage Vq according to the first feedback current Iq and the first target current Iq*. Alternatively, the first current comparison and adjustment unit 516 includes a PI regulator, and the first current comparison and adjustment unit 516 adjusts the first target voltage Vq in a PI adjustment manner according to the comparison result of the first feedback current Iq and the first target current Iq*, so that the motor first feedback current Iq can reach the first target current Iq* as quickly and stably as possible, and the first target current Iq* can be used to control the motor speed to reach the target speed ω* as quickly as possible.

[0097] The second current comparison and adjustment unit 517 obtains the second target voltage Vd according to the second feedback current Id and the second target current value Id*. The second target current value Id*=0. Alternatively, the second current comparison and adjustment unit 517 adjusts the second target voltage Vd in a PI adjustment manner according to the comparison result of the second feedback current Id and the second target current Id*, so that the motor second feedback current Id can reach the second target current Id* as quickly and stably as possible.

[0098] S117: Obtain the target voltage applied to the motor according to the first target voltage Vq and the second target voltage Vd;

[0099] The target voltage applied to the motor is obtained by coordinate transformation of the obtained first target voltage Vq and second target voltage Vd.

[0100] Specifically, the obtained first target voltage Vq and second target voltage Vd are converted from two-phase direct current to two-phase alternating current by the second coordinate inverse transformation unit 518. Specifically, the second coordinate inverse transformation unit 318 converts the first target voltage Vq and the second target voltage Vd from two-phase direct current to two-phase alternating current Va and Vb by adopting a park inverse transformation mode.

[0101] Further, the two-phase alternating current Va and Vb obtained by the second coordinate inverse transformation unit 518 are transformed from two-phase alternating current to three-phase alternating current voltage by the first coordinate inverse transformation unit 519. The three-phase alternating current voltage is the target voltage applied to the motor, which is approximately a sine wave or a saddle-shaped waveform.

[0102] S118: generating a PWM signal according to the obtained target voltage applied to the motor to control the driving circuit;

[0103] The PWM signal generation unit 520 generates a PWM signal according to the obtained target voltage applied to the motor 120, which is used to control the on-off state of the corresponding switching element of the driving circuit 410.

[0104] S119: outputting a control signal according to the obtained PWM signal to control the on-off state of the switching element of the driving circuit;

[0105] The PWM signal generated by the PWM signal generation unit 520 is transmitted to the power driving module in the controller 420, which enhances the driving capability of the PWM signal. The control signal after the driving capability enhancement is output to the control end of each switching element of the driving circuit 410, thereby controlling the on-off state of each switching element. The on-off state and on-off time of each switching element can control the voltage output from the battery pack 200 to the motor, which is approximately a sine wave or a saddle-shaped waveform, thereby enabling the motor 120 to operate according to the control mode of the controller 420.

[0106] Through such a control mode, the voltage input to the motor 120 can be approximately a sine wave or a saddle-shaped waveform, which can greatly increase the speed of the motor 120, so that the speed of the motor 120 exceeds its maximum speed.

[0107] In some embodiments, the maximum speed of the motor 120 can be increased to less than or equal to 40000 rpm by FOC field weakening control, so that when the low speed ratio of the transmission mechanism 130 is less than or equal to 15, the maximum speed of the working head can be greater than or equal to 2800 rpm.

[0108] In some embodiments, for example, if the speed of motor 120 is 40,000 rpm and the low-speed ratio of transmission mechanism 130 is 14.28, then the maximum speed of the corresponding working head is approximately 2,800 rpm. In some embodiments, for example, if the speed of motor 120 is 40,000 rpm and the low-speed ratio of transmission mechanism 130 is 12.32, then the maximum speed of the corresponding working head is approximately 3,250 rpm.

[0109] Therefore, by combining electronic speed control that changes the speed of motor 120 with adjusting the transmission ratio of multi-stage planetary transmission group 300, the speed of the working head can be adjusted. This allows the handheld power tool 100 with a two-stage reduction mechanism transmission mechanism 130, i.e., a dual-speed drill, to achieve a maximum working head speed of greater than or equal to 2800 rpm, greatly improving the speed of the dual-speed drill, increasing its working efficiency, and enhancing the user experience.

[0110] like Figure 1 and Figure 2 As shown, the handheld power tool 100 also includes an actuator sleeve 180, which is operably rotated by the user about the output shaft 141 to set the operating mode of the handheld power tool 100. Optionally, when the handheld power tool 100 is an impact drill, the actuator sleeve 180 is a function cup, operably rotated by the user about the output shaft 141 to set the operating mode of the handheld power tool 100, including drill mode, hammer mode, and screw mode. Optionally, when the handheld power tool 100 is an electric drill, the actuator sleeve 180 is a torque cup, operably rotated by the user about the output shaft 141 to set the torque of the handheld power tool 100, and the operating mode when the torque is at its maximum is drill mode, and the operating mode when the torque is not at its maximum is screw mode. Wherein, when the handheld power tool 100 is an impact drill or an electric drill, the impact drill or electric drill is the dual-speed electric drill described above in this application. This application takes the actuator sleeve 180 as the functional cup and the handheld power tool 100 as an impact drill as an example for specific explanation.

[0111] like Figure 12 As shown, the handheld power tool 100 also includes a detection element 181, which is disposed below the actuator sleeve 180 and is used to detect the rotational state of the actuator sleeve 180. The handheld power tool 100 also includes a grip portion 113, and the detection element 181 is disposed on the upper part of the grip portion 113, specifically on the top of the grip portion 113.

[0112] The controller 420 included in the hand-held power tool 100 is arranged in the housing 110 (not shown in the figure) and is communicatively connected to the detection element 181 to obtain the rotation state of the actuator sleeve 180. In some embodiments, the controller 420 is configured to obtain the working mode of the hand-held power tool 100 according to the rotation state of the actuator sleeve 180, to set the rotation speed limit of the motor 120 according to the working mode of the hand-held power tool 100, and to control the motor 120 to operate at a speed not exceeding the rotation speed limit.

[0113] In some embodiments, the detection element 181 is a Hall element. In some embodiments, the inner side of the actuator sleeve 180 is provided with at least one magnet 182, and the position of the magnet 182 is detected by the detection element 181 to detect the rotation state of the actuator sleeve 180.

[0114] In some embodiments, when the inner side of the actuator sleeve 180 is provided with only one magnet 182, the controller 420 obtaining the working mode of the hand-held power tool 100 includes: when the hand-held power tool 100 is an impact drill, the hand-held power tool 100 includes three gears, i.e., a drill gear, a hammer gear and a screw gear. In some embodiments, when the detection element 181 detects that the distance between the position of the magnet 182 and the detection element 181 is less than a preset distance, the controller 420 obtains that the hand-held power tool 100 is in the drill gear at this time. When the detection element 181 detects that the distance between the position of the magnet 182 and the detection element 181 is greater than or equal to a first preset distance, the controller 420 obtains that the hand-held power tool 100 is in the hammer gear or the screw gear at this time. The first preset distance is determined according to an empirical value, and the first preset distance is greater than or equal to 0. For example, when the magnet 182 is directly opposite the detection element 181, the distance between them is less than the first preset distance, and the controller 420 obtains that the hand-held power tool 100 is in the drill gear at this time. Similarly, when the hand-held power tool 100 is a drill, the hand-held power tool 100 includes two gears, i.e., a drill gear and a screw gear. When the detection element 181 detects that the distance between the position of the magnet 182 and the detection element 181 is less than the first preset distance, the controller 420 obtains that the hand-held power tool 100 is in the drill gear at this time. When the detection element 181 detects that the distance between the position of the magnet 182 and the detection element 181 is greater than or equal to the first preset distance, the controller 420 obtains that the hand-held power tool 100 is in the screw gear at this time.

[0115] In some embodiments, when only two magnets 182 are provided on the inner side of the actuator sleeve 180, the controller 420 determines the operating mode of the handheld power tool 100 as follows: when the handheld power tool 100 is an impact drill, the handheld power tool 100 includes three positions: drill, hammer, and screw. In some embodiments, when the detection element 181 detects that the distance between the position of either of the two magnets 182 and the target position is less than a second preset distance, the controller 420 determines that the handheld power tool 100 is in hammer or screw mode. When the detection element 181 detects that the distance between the position of the magnet 182 and the target position is greater than or equal to the second preset distance, the controller 420 determines that the handheld power tool 100 is in drill mode. When the handheld power tool 100 is an electric drill, the controller 420 determines whether the handheld power tool 100 is in drill or screw mode in a similar manner to when the handheld power tool 100 is an impact drill, and will not be described again here. The second preset distance is determined based on empirical values ​​and is greater than or equal to 0.

[0116] In some embodiments, the rotational speed limit of the drill stop is higher than that of the hammer stop and screw stop. For example... Figure 2 As shown, the handheld power tool 100 also includes an impact gear 183 and a shift washer 184. When the handheld power tool 100 is in hammer mode, the impact gear 183 is impacted. If the motor 120's speed is too high, it will accelerate the wear of the impact gear 183. When the handheld power tool 100 is in screw mode, there is a probability of shifting out of control. If the motor 120's speed is too high, the high-frequency vibration can easily cause the shift washer 184 to break. Therefore, it is necessary to further limit the speed of the motor 120 in hammer and screw modes to extend the service life of the handheld power tool 100.

[0117] In some embodiments, the speed limit of motor 120 during drill mode is set to V1, meaning the maximum speed of motor 120 during drill mode is V1. The speed limit of motor 120 during hammer and screw modes is set to V2, meaning the maximum speed of motor 120 during hammer or screw modes is V2. Wherein, V2 is less than V1. Since the maximum speed of motor 120 is less than or equal to 40,000 rpm due to FOC field weakening control, V1 is less than or equal to 40,000 rpm.

[0118] In some embodiments, when the controller 420 obtains that the hand-held power tool 100 is in the drilling mode, the controller 420 controls the maximum speed of the motor 120 to V1. Optionally, the controller 420 can increase the speed of the motor 120 to V1 by FOC field weakening control. Optionally, the controller 420 can increase the speed of the motor 120 to V1 by increasing the duty cycle of the motor 120. Optionally, the controller 420 can increase the speed of the motor 120 to V1 by increasing the conduction angle of the motor 120. In addition, the controller 420 can increase the speed of the motor 120 by any other way, which is not limited in the present application.

[0119] In some embodiments, when the controller 420 obtains that the hand-held power tool 100 is in the hammering mode or the screwing mode, the controller 420 controls the maximum speed of the motor 120 to V2. When the hand-held power tool 100 is switched from the drilling mode to the hammering mode or the screwing mode, the controller 420 needs to decrease the speed of the motor 120 from V1 to V2. Optionally, the controller 420 can decrease the speed of the motor 120 to V2 by FOC control. Optionally, the controller 420 can decrease the speed of the motor 120 to V2 by decreasing the duty cycle of the motor 120. Optionally, the controller 420 can decrease the speed of the motor 120 to V2 by decreasing the conduction angle of the motor 120. In addition, the controller 420 can decrease the speed of the motor 120 by any other way, which is not limited in the present application. When the hand-held power tool 100 is directly in the hammering mode or the screwing mode after starting, the controller 420 can also increase the speed of the motor 120 to V2 by FOC field weakening control, or increasing the duty cycle of the motor 120, or increasing the conduction angle of the motor 120, and so on.

[0120] Similarly, when the hand-held power tool 100 is a drill, and only includes two working modes of the drilling mode and the screwing mode, the controller 420 controls the speed of the motor 120 in the same way as described above, which is not described herein again.

[0121] In some embodiments, the controller 420 can control the duty cycle of the motor 120 to be fully on, i.e. increasing the duty cycle of the motor 120 to 100% to make the maximum speed of the motor 120 reach V1. In some embodiments, the controller 420 can control the duty cycle of the motor 120 to a first duty cycle to make the maximum speed of the motor 120 reach V1, i.e. the first duty cycle corresponds to the speed V1 of the motor 120. In some embodiments, the controller 420 increases the duty cycle of the motor 120 to a second duty cycle to make the maximum speed of the motor 120 reach V2, i.e. the second duty cycle corresponds to the speed V2 of the motor 120. Similarly, when the speed of the motor 120 is V1, the controller 420 controls the duty cycle of the motor 120 to decrease to the second duty cycle to make the maximum speed of the motor 120 decrease to V2.

[0122] In some embodiments, the way the controller 420 increases the conduction angle of the motor 120 includes:

[0123] To drive the motor 120 to rotate, the drive circuit 410 generally has at least six driving states, and each switching of the driving states corresponds to a commutation action of the motor 120. As shown in Figure 9 the motor 120 rotates, the drive circuit 410 generally has at least six driving states, and each switching of the driving states corresponds to a commutation action of the motor 120. As shown in Figure 13 the motor 120 rotates, the drive circuit 410 generally has at least six driving states, and each switching of the driving states corresponds to a commutation action of the motor 120. As shown in Figure 13 the motor 120 rotates, the drive circuit 410 generally has at least six driving states, and each switching of the driving states corresponds to a commutation action of the motor 120. As shown in Figure 11 It can be seen that, in a 360° commutation period, there are six commutations, and the three-phase windings of the motor 120 are all conducting for 120°, that is, the conduction angle is 120°. Generally, the Figure 13 the motor 120 rotates, the drive circuit 410 generally has at least six driving states, and each switching of the driving states corresponds to a commutation action of the motor 120. As shown in

[0124] Generally, in order to improve the weak magnetic capability and improve the speed of the motor 120, the size of the conduction angle is increased, for example, the conduction angle is increased to greater than 120°. In order to increase the conduction angle, the equivalent voltage applied to the stator winding is generally increased. In terms of a three-phase motor, increasing the conduction of the stator winding means changing from two-phase winding commutation to three-phase winding commutation, that is, from two-by-two conduction to three-by-three conduction. For example, the rotor is commutated every 30°, that is, 12 commutations are performed in a 360° commutation period, which can ensure that the three-phase windings of the motor 120 are all conducting during the commutation process, so that the conduction angle is greater than 120°, for example, the conduction angle is 150°. As shown in Figure 14 the motor 120 rotates, the drive circuit 410 generally has at least six driving states, and each switching of the driving states corresponds to a commutation action of the motor 120. As shown in Figure 14 and Figure 13 It can be seen that, in a 360° commutation period, there are six commutations, and the three-phase windings of the motor 120 are all conducting for 120°, that is, the conduction angle is 120°. Generally, the

[0125] In some embodiments, the controller 420 reduces the conduction angle of the motor 120 includes: when the conduction angle of the motor 120 corresponds to V1, the controller 420 controls the conduction angle of the motor 120 to be reduced to correspond to V2.

[0126] Optionally, the maximum speed of the working head of the hand-held power tool 100 is greater than or equal to 2800 rpm when the hand-held power tool 100 is in the drill gear. Optionally, the maximum speed of the working head of the hand-held power tool 100 is greater than or equal to 2300 rpm when the hand-held power tool 100 is in the hammer gear. Optionally, the maximum speed of the working head of the hand-held power tool 100 is greater than or equal to 2300 rpm when the hand-held power tool 100 is in the drill gear.

[0127] In the hand-held power tool 100 with the two-stage speed reduction mechanism, i.e., the double-speed electric drill, the maximum speed of the working head is greater than or equal to 2800 rpm. The speed of the hand-held power tool 100 in different working modes is limited, so that the motor 120 maintains a high speed when the hand-held power tool 100 is in the drill gear, i.e., the maximum speed of the working head is greater than or equal to 2800 rpm. When the hand-held power tool 100 is in the hammer gear or the screw gear, the speed of the motor 120 is limited to be less than that in the drill gear to avoid wear of the impact tooth 183 or the gear jumper 184 and to prolong the service life of the hand-held power tool 100. Thus, the service life of the hand-held power tool 100 is guaranteed while the working efficiency of the double-speed electric drill is high.

[0128] As shown in Figure 15 The clamping mechanism 160 includes a chuck body 161, and the chuck body 161 includes a clamping jaw 1611 for clamping a workpiece, i.e., the working head. The output shaft 141 transmits torque to rotate the chuck body 161, wherein the output shaft 141 is radially limited by a connecting hole 162 in the clamping mechanism 160, i.e., the output shaft 141 is inserted into the connecting hole 162. The maximum speed of the chuck body 161 is greater than or equal to 2800 rpm. The output shaft 141 includes an axial connecting groove 1411, specifically, an end of the output shaft 141 inserted into the chuck body 161 is provided with the axial connecting groove 1411. Figure 16 and Figure 17 The output shaft 141 is symmetrically provided with a protrusion 1412 on the upper and lower sides, and the clamping mechanism 160 includes a clamping portion 163 matched with the protrusion 1412. The output shaft 141 transmits torque to the clamping portion 163 through the protrusion 1412 to rotate the chuck body 161.

[0129] The handheld power tool 100 also includes an axial limiting member 190, which is located inside the chuck body 161. The axial limiting member 190 is used to connect the chuck body 161 and the axial connecting groove 1411, that is, the axial limiting member 190 is used to connect the chuck body 161 and the output shaft 141. The chuck body 161 includes a hole 1612, which matches the axial limiting member 190. The axial limiting member 190 passes through the hole 1612 through the chuck body 161 and then into the axial connecting groove 1411, thereby connecting the chuck body 161 and the axial connecting groove 1411.

[0130] In some embodiments, the axial limiting member 190 can be a screw 190, in which case the axial connecting groove 1411 is a threaded hole, and the connection between the screw and the threaded hole is simple and reliable. Furthermore, the axial limiting member 190 can be any other component that can perform a connecting function, and this application does not limit it. This application uses a screw 190 as an example for specific description.

[0131] To facilitate the removal of the clamping mechanism 160 from the handheld power tool 100, such as Figure 17 As shown, there is a gap A between the output shaft 141 and the chuck body 161. Specifically, there is a gap A between the protrusion 1412 of the output shaft 141 and the engaging portion 163. When the handheld power tool 100 is working, the existence of gap A causes relative displacement between the output shaft 141 and the chuck body 161. Furthermore, frequent forward and reverse rotation of the handheld power tool 100 can easily cause the axial limiting member 190 to loosen. Therefore, an anti-loosening structure 500 needs to be provided in the clamping mechanism 160 and the output shaft 141.

[0132] In some embodiments, the anti-loosening structure 500 includes an elastic element 510 and an anti-loosening material 520. The axial limiting member 190 is in direct or indirect contact with the elastic element 510 or the anti-loosening material 520 to increase the preload between the axial limiting member 190 and the axial connecting groove 1411.

[0133] In some embodiments, such as Figure 15As shown, the anti-loosening material 520 is arranged at the axial contact position between the axial limiting member 190 and the axial connecting groove 1411. When the axial limiting member 190 is a screw 190, the anti-loosening material 520 is arranged on the screw rod 191 of the screw 190. Optionally, the anti-loosening material 520 can be arranged on the entire axial contact position between the axial limiting member 190 and the axial connecting groove 1411. Optionally, the anti-loosening material 520 can be arranged on the partial axial contact position between the axial limiting member 190 and the axial connecting groove 1411. Optionally, the anti-loosening material 520 can be a Loctite glue. By arranging the anti-loosening material 520, the gap between the axial limiting member 190 and the axial connecting groove 1411 is filled by the anti-loosening material 520, so that the axial limiting member 190 is fixed in the axial connecting groove 1411, and the tightness of the connection between the axial limiting member 190 and the axial connecting groove 1411 is improved.

[0134] In some embodiments, the elastic member 510 includes an elastic sheet 511. When the axial limiting member 190 is a screw 190, the elastic sheet 511 is arranged between the screw nut 192 of the screw 190 and the chuck body 161, as shown in detail. Figure 18 By arranging the elastic sheet 511, the screw rod 191 is difficult to rotate in the threaded hole of the axial connecting groove 1411, so that the connection between the screw rod 191 of the screw 190 and the threaded hole of the axial connecting groove 1411 is more tight.

[0135] In some embodiments, the elastic member 510 includes a spring 512. When the axial limiting member 190 is a screw 190, the spring 512 is arranged between the end of the screw rod 191 (i.e. the rear end of the hand-held electric tool 100) and the axial connecting groove 1411, as shown in detail. Figure 19 By arranging the spring 512 at the end of the screw rod 191, the connection between the screw rod 191 and the threaded hole of the axial connecting groove 1411 is more tight based on the elastic extrusion of the spring 512.

[0136] In some embodiments, any one of the anti-loosening material 520, the elastic sheet 511 and the spring 512 is arranged to increase the pre-tightening force between the axial limiting member 190 and the axial connecting groove 1411. In some embodiments, any two of the anti-loosening material 520, the elastic sheet 511 and the spring 512 are arranged to increase the pre-tightening force between the axial limiting member 190 and the axial connecting groove 1411. In some embodiments, all of the anti-loosening material 520, the elastic sheet 511 and the spring 512 are arranged to increase the pre-tightening force between the axial limiting member 190 and the axial connecting groove 1411.

[0137] By setting the anti-loosening material 520 and / or the elastic piece 510, the axial limiting piece 190 can be tightly connected with the chuck body 161 and the axial connecting groove 1411. Even when the handheld electric tool 100 is frequently rotated forward and reversed, the axial limiting piece 190 will not loosen, and the tightness of the connection between the chuck body 161 and the axial connecting groove 1411 can be maintained. Thus, when the axial limiting piece 190 is always tightly connected, there will be no relative displacement between the output shaft 141 and the chuck body 161, which can effectively avoid the displacement and shaking of the chuck body 161 relative to the output shaft 141, and improve the use safety of the handheld electric tool 100. In addition, the axial movement of the chuck body 161 can also be avoided, the stress area between the chuck body 161 and the output shaft 141 is reduced, and the risk of deformation of the chuck body 161 is reduced.

[0138] In some embodiments, as shown in Figure 2 The handheld electric tool 100 also includes a PCB box 600, which is arranged inside the handheld electric tool 100 and used to store the PCB of the handheld electric tool 100. Optionally, as shown in Figure 20 A wire clamping groove 610 is arranged on the side of the PCB box 610, which is used to assemble the plurality of connecting lines in the shell 110, so that the plurality of connecting lines are received and fixed in the wire clamping groove 610, solving the problem of mutual friction between the plurality of connecting lines. At the same time, the plurality of connecting lines are received and fixed in the wire clamping groove 610, avoiding the messy situation of the connecting lines in the shell 110.

[0139] The basic principles, main features and advantages of the present application are shown and described above. Those skilled in the art should understand that the above embodiments do not limit the present application in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the protection scope of the present application.

Claims

1. An electric tool, comprising: The chuck body includes grippers for holding workpieces; An output shaft is used to transmit torque to rotate the chuck body. The output shaft and the chuck body are radially limited by a connecting hole. An axial connecting groove is provided at one end of the output shaft that is inserted into the chuck body. An axial limiting member is located inside the chuck body, and the axial limiting member connects the chuck body and the axial connecting groove; The axial limiting member is characterized in that it is in direct or indirect contact with the elastic member or the anti-loosening material to increase the preload between the axial limiting member and the axial connecting groove.

2. The power tool as described in claim 1, characterized in that, The axial limiting component is a screw.

3. The power tool as described in claim 1, characterized in that, The axial contact portion between the axial limiting member and the axial connecting groove is provided with anti-loosening material.

4. The power tool as described in claim 3, characterized in that, The anti-loosening material is natron or anaerobic adhesive.

5. The power tool as described in claim 2, characterized in that, The elastic element is disposed between the nut of the screw and the collet body.

6. The power tool as described in claim 5, characterized in that, The elastic element is a spring sheet.

7. The power tool as described in claim 2, characterized in that, The elastic element is disposed between the screw end and the axial connecting groove.

8. The power tool as claimed in claim 7, characterized in that, The elastic element is a spring.

9. The power tool as claimed in claim 1, characterized in that, The maximum rotational speed of the chuck body is greater than or equal to 2800 rpm.

10. The power tool as claimed in claim 1, characterized in that, The power tool also includes a PCB box, and the side of the PCB box is provided with a wire-holding groove.

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