Power tool

Abstract

The present invention discloses a power tool, comprising: a housing including a support portion; a cutting unit for cutting a target object and moving between a first position and a second position relative to the support portion; a transmission device connecting the driving device and the cutting unit; a changeover switch, the changeover switch being located at the third position, and when the cutting unit performs a first movement under the action of the driving device, the first movement has a first speed; the first movement is the cutting unit moving from the second position to the first position; the changeover switch is located at the fourth position, and when the cutting unit performs a second movement under the action of the driving device, the second movement has a second speed; the second movement is the cutting unit moving from the first position to the second position; the second speed is greater than the first speed. The power tool of the present invention controls the cutting unit to achieve rapid tool retraction after cutting, has high shearing efficiency and is convenient to operate.

Description

Technical Field

[0001] The present invention relates to a power tool. Background Art

[0002] Pipes include wire pipes, water pipes, etc., which are commonly found in home, engineering and other environments. In order to meet the pipe laying needs of the on-site environment, the pipes will be cut according to the usage requirements. Most of the existing pipe cutting devices are manual, and the cutting efficiency for pipes with greater hardness and other situations is relatively low. For a few electric pipe cutters, due to their unreasonable transmission structure and control process, they have problems such as low pipe cutting efficiency, large size of the machine, inconvenient carrying, and complex operation methods. Summary of the Invention

[0003] To solve the deficiencies of the prior art, the purpose of the present invention is to provide a power tool with high cutting efficiency, convenient operation and compact size.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A power tool, comprising: a housing including a support portion; a cutting unit for cutting a target object, which moves between a first position and a second position relative to the support portion under the action of a driving device; a transmission device connecting the driving device and the cutting unit; a changeover switch including at least a third position and a fourth position; when the changeover switch is in the third position and the cutting unit realizes a first movement under the action of the driving device, the first movement has a first speed; the first movement is the cutting unit moving from the second position to the first position; when the changeover switch is in the fourth position and the cutting unit realizes a second movement under the action of the driving device, the second movement has a second speed; the second movement is the cutting unit moving from the first position to the second position; the second speed is greater than the first speed.

[0006] In some embodiments, the transmission device includes:

[0007] An output shaft;

[0008] A braking assembly connected to the switch, when the switch is in the third position and the fourth position, the braking assembly is in a fifth position and a sixth position respectively;

[0009] An output gear assembly provided on the output shaft, drivingly connecting the cutting unit; when the braking assembly is in the fifth position, the output wheel assembly moves relative to the output shaft; when the braking assembly is in the sixth position, the output wheel assembly rotates around the output shaft.

[0010] In some embodiments, the output wheel assembly includes an output gear. One end of the output gear is connected to an output internal gear ring, and the braking assembly is provided at the other end. The cutting unit is connected to the output internal gear ring, and the internal gear ring drives the cutting unit to rotate.

[0011] In some embodiments, the output internal gear ring is fan-shaped or semi-circular and rotates around a fixed axis.

[0012] In some embodiments, the braking assembly includes:

[0013] A fixed ring connected to the changeover switch;

[0014] A braking internal gear ring connected to the fixed ring. The inner side of the braking internal gear ring is in transmission connection with the output shaft.

[0015] In some embodiments, the transmission device includes a planetary gear set, and the planetary gear set includes:

[0016] A sun gear connected to the output shaft;

[0017] A planetary gear meshing with the sun gear. A planetary rotating shaft is provided at the center of the planetary gear. One end of the planetary rotating shaft is connected to the planetary gear, and the other end is connected to the output gear.

[0018] In some embodiments, the sun gear includes a primary sun gear and a secondary sun gear. When the braking assembly is in the sixth position, it is in transmission connection with the secondary sun gear.

[0019] In some embodiments, a steering controller is configured to switch the drive device between forward rotation and reverse rotation according to the state of the power tool or the operation of the user, so as to realize the first movement or the second movement of the cutting unit.

[0020] In some embodiments, it includes a battery pack. The orthographic projection of the battery pack in a plane perpendicular to the front-back direction is a first projection, and the orthographic projection of the housing in a plane perpendicular to the front-back direction is a second projection. At least part of the first projection is below the second projection.

[0021] In some embodiments, it includes a main switch for controlling the start and stop of the drive device. When the drive device is started, the cutting unit realizes the first movement.

[0022] In some embodiments, the changeover switch automatically resets from the fourth position to the third position.

[0023] In some embodiments, the transmission device or the driving device includes a gear-shifting mechanism. After the cutting unit moves to the first position or the second position, the gear-shifting mechanism enables the driving device or the transmission device to be in a disengaged state; alternatively, when the cutting unit is overloaded during movement between the first position and the second position, the gear-shifting mechanism enables the driving device or the transmission device to be in a disengaged state.

[0024] An electric tool, comprising: a housing including a support portion; a cutting unit for cutting a target object and moving relative to the support portion between a first position and a second position under the action of a driving device; a transmission device for drivingly connecting the driving device and the cutting unit; the cutting unit includes a first movement and a second movement; the first movement is that the cutting unit moves from the second position to the first position under the action of the driving device; the second movement is that the cutting unit moves from the first position to the second position under the action of the driving device; the speed at which the cutting unit realizes the second movement is greater than the speed at which the cutting unit realizes the first movement.

[0025] The beneficial effects of the present invention are as follows: The electric tool of the present invention controls the cutting unit to achieve rapid retraction of the cutter after cutting, with high shearing efficiency and convenient operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention;

[0027] Figure 2 is a top view of Embodiment 1 of the present invention;

[0028] Figure 3 is a sectional view taken along the A-A plane when the braking assembly is in the fifth position in Embodiment 1 of the present invention;

[0029] Figure 4 is a sectional view taken along the A-A plane when the braking assembly is in the sixth position in Embodiment 1 of the present invention;

[0030] Figure 5 is Figure 2 a sectional view taken along the B-B plane in

[0031] Figure 6 is Figure 2 a sectional view taken along the C-C plane in

[0032] Figure 7 is an exploded view of the internal structure of Embodiment 1 of the present invention from the first perspective;

[0033] Figure 8 is an exploded view of the internal structure of Embodiment 1 of the present invention from the second perspective;

[0034] Figure 9 is an exploded view of Embodiment 1 of the present invention;

[0035] Figure 10 It is a schematic structural diagram of the second embodiment of the present invention;

[0036] Figure 11 It is a schematic partial structural diagram of the second embodiment of the present invention;

[0037] Figure 12 It is a schematic diagram of the control circuit of the third embodiment of the present invention;

[0038] Figure 13 It is a schematic diagram of the principle of the controller of the third embodiment of the present invention;

[0039] Figure 14 It is a schematic diagram of the control circuit of the fourth embodiment of the present invention. Specific embodiments

[0040] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0041] Embodiment 1

[0042] As Figure 1 shown, this embodiment relates to a power tool 10, specifically a pipe cutter for cutting various pipes, including a housing 11 and a battery pack 14. The housing 11 includes a tool part 12 and a handle part 13, and the battery pack 14 is connected to the handle part 13. Specifically, the battery pack 14 is detachably connected to the handle part 13. In other embodiments, it can also be an AC pipe cutter, which is not limited herein. A transmission device 30 and a driving device 40 are provided inside the housing 11, and several switches or switch assemblies are provided on the housing.

[0043] The tool part 12 further includes a support part 121, and a cutting unit 20 is connected to the tool part 12. The tool part 12 forms a cavity, and part of the transmission device 30 is provided in the cavity. The cavity includes a first cavity 124 and a second cavity 123. The first end of the cutting unit 20 extends into the tool part 12 and is arranged in the first cavity, and the first end of the cutting unit 20 is connected to the transmission device. The second end of the cutting unit 20 and most of the cutting unit 20 extend out of the tool part 12 and are arranged opposite to the support part 121. The support part 121 includes a positioning part 122, and the positioning part 122 is at least one curved surface or groove. The positioning part 122 is arranged opposite to the cutting unit 20, so that the support part 121 is located on one side of the pipe to be sheared, while the cutting unit 20 is located on the other side of the pipe to be sheared, and the positioning part 122 abuts against the outer wall of the pipe. The support part 121 is also provided with a first groove 122a for accommodating the cutting unit 20 after the shearing movement. Specifically, the opening of the first groove 122a is arranged at the positioning part 122, the opening faces the cutting unit 20, and the width of the first groove is slightly larger than the width of the cutting unit.

[0044] The cutting unit 20 is in transmission connection with the driving device 40 through the transmission device 30, and under the action of the driving device 40, it moves between a first position and a second position relative to the support portion 121 to achieve a first motion and a second motion. The first motion is that the cutting unit 20 moves from the second position to the first position, which in this embodiment is to complete a downward shearing action. The second motion is that the cutting unit 20 moves from the first position to the second position, which in this embodiment is to complete an upward restoring action. Specifically, the first position is Figure 1 the position where the cutting unit 20 is located as shown, and at this time, the distance between the edge of the cutting unit 20 and the positioning portion 122 should be greater than the diameter of the pipeline to be sheared. The second position is the middle position or the bottom position of the first groove 122a where the cutting unit 20 moves to. Further, the distance between the first position and the second position should be greater than or equal to the diameter of the pipeline to be sheared, at least greater than or equal to two-thirds of the pipeline diameter, to ensure complete shearing of the pipeline, or to enable the user to easily break off the sheared pipeline section after shearing the pipeline.

[0045] As Figures 3 - 8 shown, the transmission device 30 includes an output shaft 31, a driving shaft, an output gear assembly 33, a planetary gear assembly 34, and a braking assembly 32. The output shaft 31 penetrates through the first cavity 124 and the second cavity 123 and is arranged along the second axis 102. Both the output wheel assembly 33 and the braking assembly 32 are directly or indirectly connected to the output shaft 31.

[0046] The output gear assembly 33 includes an output internal gear ring 331 and an output gear 332 provided on the output shaft 31. One end of the output gear 332 is connected to the output internal gear ring 331, and the other end is provided with a braking assembly 32. Specifically, the output internal gear ring 331 in this embodiment is fan-shaped, including an output hole 331a and a gear ring portion 331b. The gear ring portion 331b has an arc-shaped tooth, and the gear ring portion 331b meshes with the output gear 332. Further, the output gear 332 is a stepped two-stage gear, that is, it includes a gear portion 332a and a transmission portion 332b, and the gear portion 332a meshes with the gear ring portion 331b. Further, the diameter of the gear portion 332a is smaller than the diameter of the transmission portion 332b, so that the lower edge of the output internal gear ring 331 abuts against the surface of the transmission portion 332b.

[0047] The cutting unit 20 is connected to the output hole 331a through the connecting component 35. The connecting component 35 includes a first fixing pin 351, a second fixing pin 352, and a third fixing pin 353. After the first fixing pin 351 and the second fixing pin 352 are connected, they are inserted into the connecting hole 21 at one end of the cutting element 20. The lower ends of the first fixing pin 351 and the second fixing pin 352 pass through the connecting hole 21 and are connected to the third fixing pin 353. The lower end of the third fixing pin 353 is connected to the output hole 331a. Specifically, a round hole is provided in the center of the second fixing pin 352. The lower end of the first fixing pin 351 is cylindrical. Correspondingly, a circular part is also included in the center of the connecting hole 21. The cylindrical lower end of the first fixing member 351 sequentially passes through the second fixing pin 352 and the connecting hole 21. Two pins are provided below the second fixing pin 352 relative to the lower end of the first fixing pin 351. The cross-section of the pins is fan-shaped or triangular, etc. Correspondingly, the connecting hole 21 also includes two hole parts with corresponding shapes. The lower end of the second fixing pin 352 is inserted into the connecting hole 21. Based on the above, the cross-sectional shape of the connecting hole 21 is consistent with the combination of the cross-sectional shapes of the lower ends of the first fixing pin 351 and the second fixing pin 352. The upper end of the third fixing pin 353 has a connecting groove 353a with the same shape as the above-mentioned connecting hole 21. The connecting groove 353a is used to install the ends of the first fixing pin 351 and the second fixing pin 352. The lower end of the third fixing pin 353 has a flat part 353b. The flat part 353b is connected to the output hole 331a. Correspondingly, the output hole 331a is also a flat hole. The special-shaped shapes of the above-mentioned output hole 331a and the connecting hole 21 can improve the connection stability and prevent relative rotation between the cutting unit 30 and the output internal gear ring. In other embodiments, one or two fixing pins can also be provided, or the connecting hole 21 and the output hole 331a are other shapes that can achieve anti-rotation, which are not limited here.

[0048] The output wheel assembly 33 is drivingly connected to the planetary gear assembly 34, and the planetary gear assembly 34 is connected to the output shaft 31. Specifically, the planetary gear assembly 34 includes a plurality of planetary gears 341 and a plurality of rotating shafts 342 provided at the centers of the planetary gears. A first sun gear 343 is meshed with the center of the planetary gear 341. The lower end of the rotating shaft 342 is connected to the planetary gear 341, and the upper end of the rotating shaft 342 is fixed to the transmission part 332b, such as Figure 6 shown, so that the output gear 332 rotates following the planetary gear 341 under certain conditions. In this embodiment, in order to achieve the above transmission, 4 planetary gears and rotating shafts are provided respectively. In other embodiments, other numbers can also be set, or other gear systems other than planetary gears can be used to replace, which are not limited here.

[0049] Further, the first sun gear 343 is arranged on the output shaft 31, and rotates under the drive of the output shaft 31, and the second sun gear 344 is arranged below the first sun gear 343. The diameter of the second sun gear 344 is larger than the diameter of the first sun gear 343, and larger than the diameter of the outer circumference of all the planetary gears. Under certain conditions, the second sun gear 344 is transmission-connected with the brake assembly 32, specifically, when the brake assembly 32 is located at the sixth position, the second sun gear 344 meshes with the brake inner gear ring 321. The first sun gear 343 and the second sun gear 344 are fixedly connected, or the first sun gear 343 and the second sun gear 344 are integrally formed. The upper surface of the second sun gear 344 is an arc surface, or the upper end of its gear part is inclined at a certain angle to ensure that when the brake assembly moves up and down, the teeth of its brake inner gear ring 321 are more easily meshed with the teeth of the second sun gear 344.

[0050] The brake assembly 32 includes a fixed ring and a brake inner gear ring 321, the fixed ring is connected to the brake inner gear ring 321, and part of the brake assembly 32 moves between the fifth position and the sixth position. Specifically, in this embodiment, the fixed ring includes a first fixed ring 322 and a second fixed ring 323, the second fixed ring 323 is sleeved on the first fixed ring 322 and the brake inner gear ring 321, the first fixed ring 322 and the brake inner gear ring 321 are arranged in parallel, and the first fixed ring 322 is arranged above the brake inner gear ring 321, and the first fixed ring 322 is fixed to other structures of the transmission device 30 or the housing 11, which plays a limiting role. Further, the second fixed ring 323 is connected to the brake inner gear ring 321 through a plurality of fixing members 324, and the fixing members 324 penetrate and bolt the second fixed ring 323 and the brake inner gear ring 321, so that the movement of the second fixed ring 323 drives the movement of the brake inner gear ring 321. Furthermore, the inner side of the brake inner gear ring 321 is covered with teeth from top to bottom, and the outer side is stepped. The lower step has a larger diameter and is provided with a groove for connecting the fixing member 324. The upper step is connected to the inner side of the first fixing ring 322. The first fixing ring 322 is provided between the upper step and the second fixing ring 323, so that the three form a close connection relationship. In this embodiment, the brake assembly 32 moves under the action of the switching switch 50. In other embodiments, the movement of the brake assembly 32 may not be controlled by the switching switch 50, but may be directly controlled by the controller 70.

[0051] The fixing ring is connected to the switching switch 50 through the connecting rod 501, and the switching switch 50 is arranged on the handle portion 13. In this embodiment, the switching switch 50 has a first end and a second end, and the switching switch 50 passes through the handle portion 13 in the left-right direction, so that the first end and the second end extend from the left and right sides of the handle portion 13 respectively. The switching switch 50 can move in the left-right direction, has a third position and a fourth position, and moves between the third position and the fourth position. Specifically, one end of the connecting rod 501 is fixedly connected to the second fixing ring 323, and one end is connected to the switching switch 50, and can also be integrally formed with the switching switch 50.

[0052] The transmission device 30 further includes a support washer 36, which is used to support and define the position of a portion of the transmission device. Specifically, the support washer 36 is used to support the brake assembly 32. Figure 3 , 4 As shown, specifically, in this embodiment, the outer edge of the support washer 36 is clamped on the corresponding groove of the inner wall of the tool part 12, so that it supports the upper mechanism, including the brake assembly and the output wheel assembly, etc. Further, the support washer 36 is arranged in the middle of the first cavity 124.

[0053] The transmission device 30 further includes a transmission gear 37, which is disposed at the lower portion of the first cavity 124. The transmission gear 37 is connected to the drive device 40 through a drive shaft 41. One end of the drive shaft 41 is disposed at the tool portion 12 to connect the transmission gear 37, and the other end of the drive shaft 41 and most of it are disposed in the handle portion 13. The drive shaft 41 is disposed substantially along the first axis 101. The transmission gear 37 is disposed at the output shaft 31 and is fixedly connected to the output shaft 31. The tooth surface of the transmission gear 37 is conical, and the conical tooth surface meshes with the conical portion at one end of the drive shaft 41.

[0054] The driving device 40 also includes a gear box 42 and a motor 43. The motor is used to output rotation, and the gear box 42 is used to reduce the above movement. The motor 43 is arranged at the rear end of the handle portion 13, and the gear box 42 is connected to the motor 43 and arranged in front of the motor 43. The gear box 42 is connected to the end of the driving shaft 41 away from the transmission gear 37 to provide a certain reduction effect. Due to the inconsistency of the transmission direction, a bevel gear is provided at the end of the driving shaft 41, and the upper part of the corresponding transmission gear 37 is a conical tooth surface.

[0055] The handle 13 is provided with a main switch 51 and a switching switch 50. The main switch 51 is used to control the start and stop of the motor 43. The switching switch 50 controls the movement of the brake assembly 32 through the connecting rod 501. A biasing element 502 is provided in the switching switch 50. The circumference of the biasing element 502 abuts against the inner wall of the switching switch 50, and the two ends abut against the inner wall of the shell, respectively, to provide a restoring force for the switching switch 50 to move between the third and fourth positions, so that the switching switch 50 automatically resets from the fourth position to the third position, ensuring a good feel and convenient operation.

[0056] The tool part 12 includes a first tool housing 125 and a second tool housing 126, and an intermediate tool housing 127 is also provided between the first and second tool housings. In this embodiment, the first tool housing 125 and the second tool housing 126 are respectively two half housings provided on the left and right of the internal structure. Specifically, the second tool housing 126 forms a part of the first cavity and the second cavity, and the first tool housing 125 forms the "cover" of the above cavities. The intermediate tool housing 127 is used to divide the internal structure, and the intermediate tool housing 127 is provided between most of the transmission devices 30 and the cutting unit 20. The first tool housing 125 and the intermediate tool housing 127 are respectively provided with a first through hole 124a and an intermediate through hole 127a for the connecting component 35 to pass through. The cutting unit 20 is provided between the first tool housing 125 and the intermediate tool housing 127. A first groove 122a is formed between the first tool housing 125 and the intermediate tool housing 127.

[0057] The cutting unit 20 includes a connecting portion 22 and a blade portion 23, and the blade portion includes a first blade portion 231 and a second blade portion 232. In this embodiment, the first blade portion 231 and the connecting portion 22 are at different heights in the left-right direction, mainly due to the connection relationship between the cutting unit 20 and the transmission device 30, or the layout within the tool part 12. Specifically, the first blade portion 231 is located in a plane perpendicular to the left-right direction to ensure the parallelism of the cutting surface of the pipeline to be processed. The second blade portion 232 is inclined relative to the first blade portion 231 and is located between the first blade portion 231 and the connecting portion 22. A protective housing is also provided on the outer peripheries of the first blade portion 231 and the second blade portion 232, covering the sides of the first blade portion 231 and the second blade portion 232 away from the pipeline to be processed to ensure the safety of the user.

[0058] The handle part 13 and the battery pack 14 are symmetrically arranged with respect to the first axis 101. The battery pack 14 is provided below the handle part 13, and the lower end surface of the battery pack 14 and the lower end surface of the tool part 12 are in the same plane in the up-down direction. Alternatively, the lower end surface of the tool part 12 is higher than the lower end surface of the battery pack 14 in the up-down direction, and at this time, the handle part 13 at least includes a portion inclined with respect to the front-back direction. That is, the first projection of the battery pack 14 in a plane perpendicular to the front-back direction, and the second projection of the housing in a plane perpendicular to the front-back direction, and at least part of the first projection is below the second projection. The above structural layout ensures that the center of the power tool is located within the handle, which is not laborious for the user to use and is convenient for placement.

[0059] The power tool 10 further includes a steering controller 60, which is configured to switch the drive device between forward rotation and reverse rotation according to the state of the power tool or the operation of the user, so as to realize the first movement or the second movement of the cutting unit 20. In this embodiment, the steering controller 60 is a sensing element, which senses the position of the change-over switch 50 and feeds it back to the circuit board 61 to control the motor to switch between forward and reverse rotations.

[0060] The power tool 10 further includes a gear shifting mechanism 421. After the cutting unit 20 moves to the first position or the second position, the gear shifting mechanism 421 enables the drive device 40 or the transmission device 30 to be in a disengaged state. Alternatively, when the cutting unit 20 moves between the first position and the second position, if the motor 43 stalls or the cutting unit 20 is subjected to a force exceeding the maximum load of the motor due to problems such as the target object, the gear shifting mechanism 421 enables the drive device 40 or the transmission device 30 to be in a disengaged state to protect the internal structure of the power tool 10. In this embodiment, the gear shifting mechanism 421 includes a plurality of elastic members and an internal gear ring provided with an inclined surface. The elastic members abut against the inclined surface. The gear shifting mechanism 421 is preferably arranged in the gearbox 42 at the front end of the motor 43, where the torque is small, facilitating the implementation of the structural arrangement. In other embodiments, the gear shifting mechanism 421 may also be other structures capable of realizing the clutch function, which are not limited herein.

[0061] The present embodiment will be further described in combination with the working process:

[0062] After the user aligns the power tool 10 to the working position, the main switch 51 is pressed, and the motor 43 starts. Driven by the motor 43, the drive shaft 41 rotates to drive the transmission gear 37 of the transmission device 30 to rotate, and then drives the output shaft 31 to rotate. At this time, the motor 43 rotates forward, and the output shaft 31 also rotates forward. The change-over switch 50 is in the third position. At this time, the braking assembly 32 is in the fifth position. As Figure 3 shown, the braking internal gear ring 321 is separated from the second sun gear 344. Driven by the output shaft 31, the first sun gear 343 transmits the rotation to the planet gear 341. The output gear 332 rotates under the action of the rotating shaft 342 at the center of the planet gear 341, rotates relative to the output shaft 31, and the output gear 332 drives the output internal gear ring 331 to rotate, thereby driving the cutting unit 20 to move from the second position to the first position, realizing the first movement and completing the cutting of the pipeline to be sheared. The user toggles the change-over switch 50 to the fourth position, and the steering controller 60 outputs a signal to the circuit board 61 to control the motor 43 to reverse, and the output shaft 31 rotates in the reverse direction. At the same time, the braking assembly 32 is in the sixth position. As Figure 4As shown, the brake internal gear ring 321 meshes with the second sun gear 344, fixing the second sun gear 344 and the first sun gear 343. The output gear 332 rotates under the action of the output shaft 31, driving the output internal gear ring 331 to rotate. Thus, the cutting unit 20 is moved from the first position to the second position, achieving the second movement and completing the retraction of the cutting unit 20. Since the drive of the second movement does not pass through the deceleration of the planetary gear assembly 34 and directly depends on the movement of the output gear 31, the speed of the second movement is greater than that of the first movement, achieving the effect of rapid tool retraction. In this embodiment, through experimental testing, the speed of the second movement is at least three times that of the first movement. By means of a switch, the tool retraction can be achieved, improving the working efficiency of the tool.

[0063] Embodiment 2

[0064] As Figures 10 - 11 shown, the components that are the same or similar in this embodiment and Embodiment 1 adopt the same reference numerals. For the convenience of description, only the differences from Embodiment 1 will be elaborated in this embodiment.

[0065] A steering switch 52 and a brake switch 53 are provided on the housing 11. The steering switch 52 moves between the left position and the right position to control the motor 43 to rotate forward and backward respectively. The brake switch 53 controls the brake assembly to move between the third position and the fourth position, realizing the separation and meshing of the brake assembly and the sun gear. In this embodiment, after the user completes the first action of shearing, the user needs to actively adjust the steering switch 52 to reverse the motor and then adjust the brake switch 53. The advantage of this structure is high stability. In other embodiments, the brake switch 53 and the steering switch 52 are electrically connected, so that after the brake switch 53 moves to the fourth position, the steering switch 52 is automatically toggled to the right position, or the steering switch 52 is controlled by the circuit board 61 to perform the above actions, finally realizing the reverse rotation of the motor 43.

[0066] Embodiment 3

[0067] As Figures 12 - 13 shown, the components that are the same or similar in this embodiment and Embodiments 1 and 2 adopt the same reference numerals. For the convenience of description, only the differences from Embodiments 1 and 2 will be elaborated in this embodiment.

[0068] The electric tool in this embodiment, especially the electric pipe cutter, further includes a controller 70, which includes any one or a combination of a single-chip microcomputer or a microcontroller (MCU), an ARM chip (a high-performance RISC (reduced instruction set computing) microprocessor, Advanced RISC Machine), and a DSP chip (a general-purpose digital signal processor). The controller 70 is arranged in the circuit board 61 and performs logical operations according to the input signals to control the rotation state of the motor.

[0069] The circuit board 61 is disposed between the battery pack 40 and the handle portion 13. Specifically, the circuit board 61 can be disposed between the motor 43 and the battery pack 40 within the handle portion 13, where there is a connection seat for the battery pack 40, and the circuit board 61 can be disposed within the connection seat. The power supply circuit is electrically connected to the controller 70 and is used to convert the electrical energy from the power supply into electrical energy available for the controller 70 and other circuit components to operate. In this embodiment, the power supply is the battery pack 40. Therefore, the power supply circuit can include a DC-DC conversion chip. Those skilled in the art should understand that the power supply is not limited to the scenario of using the battery pack 40, and it can also supply power to each circuit element through the mains power or an AC power supply, in cooperation with corresponding rectification, filtering, and voltage regulation circuits. At this time, the power supply circuit includes rectification, filtering, and voltage regulation circuits, and at this time, the circuit board 61 can be disposed at other vacant positions of the handle portion 13.

[0070] The main switch SW2 on the handle portion 13 is electrically connected to the controller 70. The opening and closing of the main switch SW2 are used to control the start and stop of the motor 43. When the main switch SW2 is closed, the motor 43 can rotate forward, thereby driving the cutting unit 20 to achieve the first movement. In this embodiment, SW2 is a mechanical switch, preferably a high-current mechanical switch. The controller 70 can detect the off signal of the switch of SW2, perform corresponding logical operations and judgments, and output signals to other components.

[0071] The switching switch SW1 is further provided on the housing 11. The switching switch SW1 is electrically connected to the controller 70 and outputs a switching state signal SW1_C according to the change of the state of the switching switch SW1. The electric pipe cutter further includes a hardware and arithmetic element 90 disposed on the circuit board 61. The hardware and arithmetic element 90 performs an AND operation according to the switching state signal SW1_C and another input signal to control the motor 43 to reverse and drive the cutting unit 20 to achieve the second movement. At the same time, the switching state signal SW1_C is transmitted to the controller 70, and the controller 70 performs logical judgments and operations according to the SW2 off signal and the switching state signal SW1_C, and finally outputs signals to other components.

[0072] As Figure 12As shown, the electric pipe cutter of this embodiment further includes a MOS transistor assembly (Q1, Q2, Q3, Q4), and the controller is not shown in the figure. The driving control signal output by the MOS transistor assembly controls the above-mentioned motor 43 to rotate forward or reverse. In other embodiments, the MOS transistor assembly can also be a selectable field effect transistor, IGBT transistor, etc., which is not limited here. The controller 70 can be connected to the hardware drive circuit 80 through a plurality of drive ports. The hardware drive circuit 80 is electrically connected to the winding of the motor 43 to make the signal voltage conform to the applicable voltage of the MOS transistor assembly, thereby driving the rotor of the brushed motor of this embodiment to operate. In other embodiments, the motor can also be a brushless motor, and the circuit should be adjusted adaptively. One end of the MOS transistor assembly is electrically connected to the drive signal output end of the hardware drive circuit 80 respectively, and the other end of the MOS transistor assembly is electrically connected to the winding of the motor 43. Q1, Q2, Q3, and Q4 change the on state according to the signal output by the controller 70. Specifically, when SW2 is closed, the circuit is turned on, and at the same time, a certain signal is output to the controller 70, and Q1 and Q4 are turned on to drive the motor 43 to rotate forward. On the contrary, when SW2 is disconnected, the circuit is disconnected, and at the same time, a certain signal is output to the controller 70, and Q1 and Q4 are not turned on, and the motor 43 stops operating. In other embodiments, the drive signal applied by the controller 70 to the hardware drive circuit can be a PWM control signal, which can control the motor to accelerate, decelerate, rotate counterclockwise or clockwise.

[0073] The changeover switch SW1 has two states: closed and open. The changeover switch SW1 outputs a changeover status signal SW1_C to the hardware AND operation element 90. When SW1 is closed, a high level is output to the hardware AND operation element 90. When SW1 is open, a low level is output to the hardware AND operation element 90. The hardware AND operation element 90 performs an AND operation on the changeover status signal SW1_C and the input signal. Only when both the changeover status signal SW1_C and the output signal of the controller 70 are high levels, a high level drive signal is output to the subsequent elements. Specifically, after SW1 is closed, the hardware AND operation element 90 detects that the changeover status signal SW1_C is at a high level. The hardware AND operation element 90 detects the output signal of the controller 70 and performs a logic operation. When both the input signal and the changeover status signal SW1_C are at high levels, the hardware AND operation element 90 outputs a high level to the hardware drive circuit 80. The hardware drive circuit 80 outputs a high level drive signal to Q2 and Q3, and Q2 and Q3 are turned on to drive the motor 43 to rotate in the reverse direction. On the contrary, after SW1 is open, the hardware AND operation element 90 detects that the changeover status signal SW1_C is at a low level. The hardware AND operation element 90 outputs a low level to the hardware drive circuit 80. The hardware drive circuit 80 outputs a low level drive signal to Q2 and Q3, and Q2 and Q3 are not turned on, and the motor 43 stops rotating. In this embodiment, the changeover switch SW1 is an electronic switch, and the input voltage value does not match the MOS transistor assembly. The hardware drive circuit 80 is used to improve the drive capability of the changeover status signal SW1_C so that the output signal matches the MOS transistor assembly. In this embodiment, the hardware AND operation element 90 is used to perform the AND operation judgment instead of directly using the controller 70 for logic operation, which can ensure the response speed of the circuit and the stability of the circuit operation.

[0074] As Figure 13 shown, when the changeover switch SW1 is closed or open, the controller 70 also receives the changeover status signal SW1_B. When the main switch SW2 is closed or open, the controller 70 receives the main switch signal SW1_A. The controller 70 makes a judgment based on the changeover status signal SW1_B, the main switch signal SW1_A, and the input signal S. When the electric pipe cutter is in a non-special working condition, a high level signal H1 is output to the hardware AND operation element 90. After the AND operation result is high, it is output to the hardware drive circuit 80 and converted into a high level drive signal MH1 to the MOS transistor assembly to drive the motor 43 to reverse.

[0075] The input signal S is a signal obtained by the controller 70 according to the state of the cutting unit 20. The input signal S includes two types of signals, namely high and low levels. Specifically, the above special working conditions at least include a shutdown condition, a braking condition or a speed regulation condition. When it is at least one of the shutdown condition, the braking condition or the speed regulation condition, the controller 70 outputs a low-level signal to the hardware AND operation element 90. After the AND operation result is low, it is output to the hardware drive circuit 80 and converted into a low-level drive signal to the MOS transistor assembly, and the motor 43 is not driven to move.

[0076] The shutdown condition is a situation where power supply to the motor 43 is stopped. The motor 43 still has a certain output rotational speed under the action of inertia. The shutdown condition is generally applicable when the electric pipe cutter completes forward cutting, that is, when the cutting unit 20 completes or is about to complete the first movement, and is also applicable to other situations where the user needs the tool to stop. The shutdown condition of the motor 43 is achieved by at least one of the following actions, but is not limited thereto: a. The main switch SW2 is disconnected, and the changeover switch SW1 is disconnected; b. The main switch SW2 is closed, and the changeover switch SW1 is closed; c. The detection element detects that the blade moves to the shutdown position. The corresponding usage scenario for action a is: after the main switch SW2 of the electric pipe cutter is pressed and the cutting unit 20 completes forward cutting, the user releases the main switch SW2 but does not press the changeover switch SW1. At this time, the signal output by the controller 70 is a low level. The corresponding usage scenario for action b is: when the main switch SW2 is in the closed state and the changeover switch SW1 is closed again, the controller 70 outputs a low-level signal. After the AND operation, a low-level drive signal is output, and the motor 43 does not perform a reverse action; or when the changeover switch SW1 is in the closed state and the main switch SW1 is closed again, the controller 70 outputs a low-level signal. After the AND operation, a low-level drive signal is output, and the motor 43 does not perform a reverse action. The corresponding usage scenario for action c is: the electric pipe cutter also includes a detection element. When the electric pipe cutter almost completes forward cutting of the target object, the cutting unit 20 moves from the second position to the shutdown position close to the first position. After the detection element detects that the cutting unit 20 reaches the shutdown position, a corresponding input signal S is generated and sent to the controller 70, and a low-level signal is output. Specifically, the detection element can be a sensor, especially a Hall element sensor. Then, a magnetic body is provided in the cutting unit 20. When the cutting unit 20 moves to the shutdown position, the Hall sensor senses the magnetic body and outputs a corresponding signal. In other embodiments, it can also be other types of sensors or detection elements, which are not limited herein.

[0077] When the electric pipe cutter is in the braking condition, the cutting unit 20 stops moving. Specifically, the cutting unit 20 and the transmission device 30 are in a disengaged state, or the inside of the transmission device 30 is in a disengaged state, or the transmission device and the driving device 40 are in a disengaged state, or the inside of the driving device 40 is in a disengaged state, so that the cutting unit 20 can stop moving immediately. The above disengaged state is realized by setting a shifting mechanism in the electric pipe cutter. Alternatively, the controller 70 outputs signals to Q3 and Q4 according to the received signals, directly short-circuits the MOS transistor assembly, and further enables the motor 43 to stop moving quickly, so that the cutting unit 20 can stop moving immediately. The braking condition is achieved by at least the following actions, but not limited to this: the detection element detects that the blade moves to the braking position. For the braking condition, when the electric pipe cutter completes the forward cutting of the target object, the cutting unit 20 moves from the second position to the first position, which is the braking position. After the detection element detects that the cutting unit 20 reaches the braking position, a corresponding input signal S is generated and sent to the controller 70, and a low-level signal is output. When the electric pipe cutter performs reverse retraction of the blade, the cutting unit 20 moves from the first position to the second position, which is the braking position.

[0078] In other embodiments, when the shutdown condition does not include the above-mentioned situation b, the braking condition further includes the following actions: the main switch is always in the closed state. After the changeover switch SW1 is closed, the controller 70 outputs a signal to the hardware AND operation element 90, and then controls the motor 43 to reverse. After the main switch SW2 is turned off, the cutting unit 20 brakes. At this time, the cutting unit 20 remains at the angle desired by the user, which is beneficial to controlling the reverse opening angle according to the thickness of the pipe and saving the cutting time.

[0079] In another embodiment, the braking condition is set to be automatically executed after the shutdown condition. Specifically, only one position is set in the electric pipe cutter, which can be a shutdown position set close to the first position, or a braking position similar to or the same as the first position. Preferably, it is a shutdown position, and the sliding movement of the cutting unit 20 driven by the inertia deceleration of the motor can be reserved. According to the time and distance of the above sliding movement, the braking condition can be configured to be automatically executed T seconds after the completion of the stop condition.

[0080] The electric pipe cutter also has a speed control switch or the main switch is an electronic switch with speed control function, etc. When the electric pipe cutter is in the speed control condition, the main switch SW2 has a seventh position and an eighth position. When the main switch SW2 is in the eighth position, it is in the off state. When the main switch SW2 is in the seventh position, it is in the fully closed state. At this time, the motor outputs the maximum speed. When the main switch SW2 is between the seventh position and the eighth position, the output speed of the motor changes according to the position of the main switch. Specifically, by changing the position of the main switch SW2, the resistance value of the component is changed, and thus the speed of the motor is adjusted. It can also be a switch based on other principles, which is not limited here. When the main switch SW2 is between the seventh position and the eighth position, the input signal S of the controller 70 is at a low level, and the controller 70 outputs a low-level signal. In other embodiments, the electric pipe cutter includes a speed control switch SW3. The speed control switch SW3 has at least a seventh position and an eighth position, and the seventh position and the eighth position respectively correspond to different speeds of the motor. The speed control switch SW3 also has a ninth position. When it is in the ninth position, the speed control switch is in the off state. When the speed control switch SW3 is in the seventh position or the eighth position, the input signal S of the controller 70 is at a low level, and the controller 70 outputs a low-level signal.

[0081] In this embodiment, the speed at which the cutting unit 20 implements the second movement is greater than the speed at which the cutting unit implements the first movement, and its implementation mainly follows the principle in Embodiment 1. In this embodiment, when the cutting unit 20 completes the second movement and moves near the second position, there is also a stop position, and there is also a braking position at the second position. The control method is the same as above.

[0082] The special condition also includes the self-stop condition, which is a similar condition to the stop condition. In this embodiment, after the motor 43 stops moving forward, that is, after completing the forward stop condition or braking condition, if the main switch SW2 is closed again, the controller 70 does not output a signal or outputs a low-level signal to the motor. Only when the controller detects that the change-over switch SW1 is closed again, the controller 70 outputs a high-level signal to the motor 43. After the motor 43 stops moving backward, that is, after completing the reverse stop condition or braking condition, if the change-over switch SW1 is closed again, the controller 70 does not output a signal or outputs a low-level signal to the motor. Only when the controller detects that the main switch SW2 is closed again, the controller 70 outputs a high-level signal to the motor 43. The self-stop condition can prevent the cutting unit 20 that has reached the bottom position (the first position or the second position) from moving, causing damage to the mechanical structure, especially the inside of the transmission device.

[0083] In other embodiments, the following scheme is adopted for the self-stop condition: after the motor 43 stops moving, if the main switch or the changeover switch is closed again, the controller 70 outputs a signal to control the motor to stop immediately after starting for t seconds. Only when the controller 70 detects that the changeover switch or the main switch is closed again, the controller 70 outputs a high-level signal to the motor 43. Specifically, when t ≤ 2s, in this embodiment, the mechanical structure of the electric pipe cutter, especially the transmission device, is allowed to withstand the phenomenon such as gear slipping caused by moving towards the bottom position for t seconds, so that the user can hear the "clicking" sound from the electric pipe cutter, making the user realize that the cutting unit has reached the position where it needs to stop, and then stop immediately to protect the mechanical structure. The detection element also works normally under the self-stop condition to ensure the situation where the cutting unit has not moved to the second position, the first position or the stop position after the aforementioned motor stops moving.

[0084] Embodiment 4

[0085] As Figure 14 shown, the components that are the same as or similar to those in Embodiments 1, 2, and 3 in this embodiment are labeled with the same reference numerals. For the sake of description, only the differences from Embodiments 1, 2, and 3 will be elaborated in this embodiment. In this embodiment, both the main switch J1 and the changeover switch J2 are mechanical switches. The controller 70 can detect the signals of both, perform AND operations and the like inside the controller 70, and the control method is the same as that in Embodiment 3.

[0086] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the above embodiments do not limit the present invention in any form. Any technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. An electric tool, characterized in that, it includes: a housing including a support portion; a cutting unit for cutting a target object, which moves between a first position and a second position relative to the support portion under the action of a driving device; a transmission device connecting the driving device and the cutting unit; a changeover switch including at least a third position and a fourth position; when the changeover switch is in the third position, the cutting unit realizes a first movement under the action of the driving device: the cutting unit moves from the second position to the first position; when the changeover switch is in the fourth position, the cutting unit realizes a second movement under the action of the driving device: the cutting unit moves from the first position to the second position; the speed at which the cutting unit realizes the second movement is greater than the speed at which the cutting unit realizes the first movement; the transmission device includes: an output shaft; a braking assembly connected to the changeover switch, and when the changeover switch is in the third position and the fourth position, the braking assembly is respectively in a fifth position and a sixth position; a planetary gear set including a sun gear connected to the output shaft, the sun gear including a first sun gear and a second sun gear; a planetary gear meshing with the first sun gear; an output wheel assembly provided on the output shaft and drivingly connected to the cutting unit; when the braking assembly is in the fifth position, the output wheel assembly rotates following the planetary gear, so that the output wheel assembly moves relative to the output shaft; when the braking assembly is in the sixth position, the second sun gear is drivingly connected to the braking assembly, and the output wheel assembly moves along with the output shaft.

2. The electric tool according to claim 1, characterized in that, the output wheel assembly includes an output gear, one end of the output gear is connected to an output internal gear ring, and the other end is provided with the braking assembly; the cutting unit is connected to the output internal gear ring, and the internal gear ring drives the cutting unit to rotate.

3. The electric tool according to claim 2, characterized in that, the output internal gear ring is fan-shaped or semi-circular and rotates around a fixed axis.

4. The electric tool according to claim 1, characterized in that, the braking assembly includes: a fixing ring connected to the changeover switch; a braking internal gear ring connected to the fixing ring, and the inner side of the braking internal gear ring is drivingly connected to the output shaft.

5. The electric tool according to claim 1, characterized in that, a planetary shaft is provided at the center of the planetary gear, one end of the planetary shaft is connected to the planetary gear, and the other end is connected to the output gear.

6. The electric tool according to claim 1, characterized in that, it includes a steering controller for switching the driving device between forward rotation and reverse rotation according to the state of the electric tool or the operation of the user, so as to realize the first movement or the second movement of the cutting unit.

7. The electric tool according to claim 1, characterized in that, it includes a battery pack, the orthographic projection of the battery pack in a plane perpendicular to the front-back direction is a first projection, the orthographic projection of the housing in a plane perpendicular to the front-back direction is a second projection, and at least part of the first projection is below the second projection.

8. The electric tool according to claim 1, It is characterized in that it includes a main switch for controlling the start and stop of the driving device. When the driving device starts, the cutting unit realizes a first movement.

9. The power tool according to claim 1 It is characterized in that the change-over switch automatically resets from the fourth position to the third position.

10. The power tool according to claim 1 It is characterized in that the transmission device or the driving device includes a gear skipping mechanism. After the cutting unit moves to the first position or the second position, the gear skipping mechanism makes the driving device or the transmission device in a disengaged state; alternatively, when the cutting unit is overloaded during movement between the first position and the second position, the gear skipping mechanism makes the driving device or the transmission device in a disengaged state.

11. A power tool It is characterized in that it includes: a housing including a supporting part; a cutting unit for cutting a target object and moving between a first position and a second position relative to the supporting part under the action of a driving device; a transmission device for drivingly connecting the driving device and the cutting unit; the cutting unit includes a first movement and a second movement; the first movement is that the cutting unit moves from the second position to the first position under the action of the driving device; the second movement is that the cutting unit moves from the first position to the second position under the action of the driving device; the speed at which the cutting unit realizes the second movement is greater than the speed at which the cutting unit realizes the first movement, it further includes a change-over switch and a braking assembly. The braking assembly is connected to the change-over switch. The braking assembly includes a braking internal gear ring; an output shaft driven to rotate by the driving device; a planetary gear set including a sun gear connected to the output shaft. The sun gear includes a first sun gear and a second sun gear; planetary gears meshing with the first sun gear; an output wheel assembly drivingly connecting the cutting unit, and the output wheel assembly rotates with the planetary gears; when the change-over switch is in the third position and the braking assembly is in the fifth position, the braking internal gear ring is separated from the second sun gear to realize the first movement; when the change-over switch is in the fourth position and the braking assembly is in the sixth position, the braking internal gear ring meshes with the second sun gear to realize the second movement.

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