Hand-held power tool

Abstract

This invention relates to a handheld power tool, comprising a housing, a motor assembly and a transmission assembly mounted on the housing, a switch assembly connected to the motor assembly, a shift assembly connected to the transmission assembly, and an output end driven by the transmission assembly. The switch assembly includes a switch element mounted on the housing and a trigger for actuating the switch element. The shift assembly includes a shift element connected to the transmission assembly and a button for moving the shift element. The switch assembly is a speed control switch, and the output speed of the motor assembly is adjusted by the pressing stroke of the trigger. The trigger includes a base and a limiting part disposed on the base. The shift assembly includes a stop part corresponding to the limiting part, and the limiting part abuts against the stop part. This invention can output a lower force at the speed required by the user and overcomes the limitation of traditional planetary gear reduction devices that cannot achieve a speed ratio of less than 3 between high-speed and low-speed states, effectively meeting the diverse work needs of users.

Description

[Technical Field]

[0001] This invention relates to the field of power tools, and in particular to a handheld power tool used in decoration, construction and other similar applications. [Background Technology]

[0002] Power tools are instruments that use a motor assembly to drive a working head in reciprocating motion. To convert the high-speed, low-torque force of the motor assembly into the low-speed, high-torque force required by the user, a planetary gear reducer is typically installed between the motor assembly and the working head. With increasing user demands, handheld power tools on the market, especially electric drills, often incorporate speed control mechanisms within the planetary gear reducer, allowing users to adjust the drill's output speed according to their needs. Typical electric drills have high-speed and low-speed gears, manually switched via a gear-adjusting mechanism.

[0003] For a reference to existing speed control devices, see Chinese Utility Model Patent No. 200920202451.8, published on September 29, 2010, which discloses a dual-speed DC electric drill, including a gearbox and a translational gear shifting device connected to the speed-changing gear inside the gearbox. The shift lever of the translational gear shifting device extends out of the gearbox housing, and the gearbox housing is provided with an axial oblong hole for the shift lever to pass through and slide during shifting. The user can switch between high speed and low speed by moving the shift lever.

[0004] However, existing planetary gear reducers require multiple stages of planetary gears to achieve lower output speeds, resulting in larger overall sizes of power tools and hindering miniaturization. Furthermore, based on the theoretical model of planetary gears, the reduction ratio of each stage is 1 + Z3 / Z1, where Z3 is the number of teeth on the internal gear ring and Z1 is the number of teeth on the sun gear, with a reduction ratio of at least 3 for each stage. When designing an electric drill, if the speed ratio between high and low speeds needs to be less than 3, traditional planetary gear reducers are generally unable to achieve this, thus failing to meet the diverse operational needs of users.

[0005] Therefore, it is indeed necessary to provide an improved handheld power tool to overcome the shortcomings of the existing technology. [Summary of the Invention]

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a handheld power tool that can output low speed and has wider applicability.

[0007] The present invention solves the problems of the prior art by adopting the following technical solution: A handheld power tool includes a housing, a motor assembly and a transmission assembly mounted on the housing, a switch assembly connected to the motor assembly, a shift assembly connected to the transmission assembly, and an output end driven by the transmission assembly. The switch assembly includes a switch element mounted on the housing and a trigger for triggering the switch element. The shift assembly includes a shift element connected to the transmission assembly and a button for moving the shift element. The switch assembly is a speed control switch, and the output speed of the motor assembly is adjusted by the pressing stroke of the trigger. The trigger includes a base and a limiting part disposed on the base. The shift assembly includes a stop part corresponding to the limiting part, and the limiting part abuts against the stop part.

[0008] A further improvement is that the stop is connected to the button and moves as the button moves.

[0009] A further improvement is that the stop portion is located between the button and the base, and the stop portion is at least partially located between the trigger and the switching element.

[0010] A further improvement is as follows: the output end includes a first state and a second state operating at different speeds; the transmission component includes a movable internal gear ring; the button includes a first position corresponding to the first state and a second position corresponding to the second state; the shifting element is connected to the internal gear ring; and the button is moved to switch between the first state and the second state.

[0011] A further improvement is as follows: the end face of the substrate facing the stop is provided with a slide rail, the stop moves within the slide rail, and the limiting part is located within the slide rail, so that the trigger cannot be pressed all the way down, thereby limiting the maximum output speed of the motor assembly.

[0012] A further improvement is as follows: the slide rail includes a first slide rail corresponding to the first position and a second slide rail corresponding to the second position, and the limiting part is provided in at least one of the two slide rails.

[0013] A further improvement is as follows: the first state is a low speed gear, and the second state is a high speed gear. In the first state, the stop part moves within the first slide rail; in the second state, the stop part moves within the second slide rail, and the limiting part is located in the second slide rail.

[0014] A further improvement is as follows: the shift assembly includes an intermediate plate fixed to the housing and a guide connecting the shift element and the button. The intermediate plate is provided with a through guide groove, and the guide moves within the guide groove.

[0015] A further improvement is as follows: the motor assembly has a first axis extending in the front-rear direction, the button moves along a second axis perpendicular to the first axis, and the extension direction of the guide groove is set at an angle to the second axis.

[0016] A further improvement is as follows: the button includes a raised rib extending from the end face toward the middle plate, and the guide abuts against the raised rib.

[0017] A further improvement is as follows: the guide includes a pawl connecting the shifting element and a guide post extending downward from the bottom of the pawl, the guide post extending through the guide groove and abutting against the rib.

[0018] Compared with the prior art, the present invention has the following beneficial effects: During the pressing process of the trigger, the limiting part abuts against the stop part, preventing the trigger from being pressed to its full pressing stroke (i.e., not pressed all the way down). Therefore, the maximum output speed of the motor assembly is limited, and the output end can output a lower force at the speed required by the user. Furthermore, the end face of the base facing the stop part is provided with a slide rail, which includes a first slide rail corresponding to low speed and a second slide rail corresponding to high speed. By placing the limiting part in the second slide rail, since the maximum output speed of the motor assembly is limited, even in high-speed mode, the user can obtain a lower force at the speed. This overcomes the limitation of traditional planetary gear reduction devices that cannot achieve a speed ratio of less than 3 between high-speed and low-speed modes, effectively meeting the diverse work needs of users. [Attached Image Description]

[0019] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings:

[0020] Figure 1 This is a schematic diagram of a handheld power tool according to a preferred embodiment of the present invention, which is currently in low speed mode.

[0021] Figure 2 This is a schematic diagram of a handheld power tool according to a preferred embodiment of the present invention, which is currently in high-speed mode;

[0022] Figure 3 yes Figure 1 The diagram shows the structure of the gear shifting component in the handheld power tool when it is in two different positions.

[0023] Figure 4 yes Figure 3 A schematic diagram of the shift assembly from another angle;

[0024] Figure 5 yes Figure 1 A schematic diagram of the gear shift assembly and switch assembly in the handheld power tool shown from the first angle;

[0025] Figure 6 yes Figure 5 A schematic diagram of the shift assembly and switch assembly from a second angle;

[0026] Figure 7 yes Figure 5 A schematic diagram of the shifting assembly and the switch assembly from a third angle;

[0027] Figure 8 yes Figure 3 A schematic diagram showing the connection between the intermediate plate and the guide in the shift assembly;

[0028] Figure 9 yes Figure 3 A schematic diagram showing the connection between the buttons and guides in the shift assembly;

[0029] Figure 10 yes Figure 1 The diagram shows the structure of the stop and trigger of a handheld power tool, which is currently in low speed mode.

[0030] Figure 11 yes Figure 1 The diagram shows the structure of the stop and trigger of a handheld power tool, which is currently in high-speed mode.

[0031] Figure 12 yes Figure 1 The diagram shows the structure of the trigger in the handheld power tool.

[0032] Figure 13 yes Figure 12 A schematic diagram of the trigger from another angle.

Detailed Implementation Methods

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0034] The terminology used in this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. For example, terms such as "upper," "lower," "front," "rear," "left," and "right" that indicate orientation or positional relationship are based solely on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0035] Please see Figure 1 and Figure 2As shown, the preferred embodiment of the present invention relates to a DC-powered electric drill 100, suitable for tightening or loosening screws and drilling holes in walls. The drill 100 includes a housing 1, a motor assembly 2 and a transmission assembly 3 mounted on the housing 1, a switch assembly 4 connected to the motor assembly 2, a shift assembly 5 connected to the transmission assembly 3, an output terminal 20 driven by the transmission assembly 3, a control assembly 6 controlling the motor assembly 2, and a battery pack 200 that powers the motor assembly 2. The battery pack 200 is detachably mounted on the housing 1 for charging. Specifically, the switch assembly 4 is electrically connected to the control assembly 6. When the user presses the switch assembly 4, the motor assembly 2 rotates at high speed, and the force is transmitted to the output terminal 20 via the transmission assembly 3. A bit is clamped at the output terminal 20, allowing the drill to operate on the workpiece.

[0036] In this embodiment, the transmission component 3 is a planetary gear reduction mechanism, suitable for converting the high-speed, low-torque force output by the motor component 2 into the low-speed, high-torque force required by the user. To meet diverse user needs, the output end 20 includes a first state and a second state operating at different speeds. Correspondingly, the planetary gear reduction mechanism has a movable internal gear ring 31. The first state is a low-speed state, in which the internal gear ring 31 participates in the deceleration process, and the output end 20 operates at a low speed. The second state is a high-speed state, in which the internal gear ring disengages and does not participate in the deceleration process, and the output end 20 operates at a high speed. The speed in the high-speed state is higher than the speed in the low-speed state.

[0037] Furthermore, the aforementioned shift assembly 5 is connected to the internal gear ring 31 of the planetary gear reduction mechanism. When the user moves the shift assembly 5, the internal gear ring 31 can be moved to switch between the first state and the second state.

[0038] Please see Figure 1 and Figure 2 As shown, the aforementioned housing 1 includes a main body 11 housing the motor assembly 2 and the transmission assembly 3, a grip portion 12 connected to the main body 11, and a connecting portion 13 located at the end of the grip portion 12. The main body 11 and the connecting portion 13 are located on the upper and lower sides of the grip portion 12, respectively. Furthermore, the grip portion 12 and the main body 11 are angled to make the user grip more comfortable and ergonomic. The switch assembly 4 is installed on the upper end of the grip portion 12 near the main body 11. The user can grasp the grip portion 12 with their entire palm and press the switch assembly 4 with a single index or middle finger, making operation more comfortable and convenient.

[0039] In this embodiment, the battery pack 200 is detachably installed in the joint 13, the motor assembly 2 has a first axis A1 extending in the front-rear direction, and the insertion direction of the battery pack 200 is approximately the same as the extension direction of the first axis A1. This arrangement allows the electric drill 100 to be stably placed on the working surface with the battery pack 200 as a support.

[0040] Optionally, the nominal voltage of the battery pack 200 can be greater than or equal to 10V and less than or equal to 20V. For example, the nominal voltage of the battery pack 200 can be 12V, 18V, 20V, etc. Optionally, the nominal voltage of the battery pack 200 can be greater than or equal to 20V and less than or equal to 100V. For example, the nominal voltage of the battery pack 200 can be 24V, 40V, 56V, 80V, etc.

[0041] Optionally, the number of battery cells in a single battery cell group in the battery pack 200 can be greater than or equal to 3 and less than or equal to 5. For example, the number of battery cells in a single battery cell group can be 3, 4, or 5. Optionally, the number of battery cells in a single battery cell group in the battery pack 200 can be greater than or equal to 6 and less than or equal to 25. For example, the number of battery cells in a single battery cell group can be 6, 10, 14, 20, etc.

[0042] In this embodiment, the aforementioned switch assembly 4 includes a switch element 41 mounted on the housing 1 and a trigger 42 that triggers the switch element 41. Furthermore, the switch assembly 4 is a speed control switch, and the output speed of the motor assembly 2 is adjusted by the pressing stroke of the trigger 42. The output speed of the motor assembly 2 is approximately proportional to the pressing stroke of the trigger 42. Specifically, if the user presses the trigger 42 to its full pressing stroke (i.e., fully pressed), the motor assembly 2 operates at its maximum output speed; if the user presses the trigger 42 to half its pressing stroke, the motor assembly 2 operates at half its maximum output speed.

[0043] Please see Figures 3 to 7 As shown, the shift assembly 5 includes a shift element 51 connected to the internal gear ring 31 of the transmission assembly 3, a button 52 for moving the shift element 51, a stop part 53 connected to the button 52, an intermediate plate 54 fixed to the housing 1, and a guide 55 connected between the shift element 51 and the button 52. The button 52 includes a first position corresponding to the first state and a second position corresponding to the second state. The user can switch between the first state and the second state by moving the button 52.

[0044] Figure 3 The diagram shows the different positions of the shift element 51 (51') and the internal gear ring 31 (31') in the two states.

[0045] In this embodiment, the button 52 is located between the transmission assembly 3 and the switch assembly 4. The button 52 extends along the second axis A2, which is perpendicular to the first axis A1, and both ends of the button 52 protrude outside the housing 1 for the user to press. Thus, while gripping the handle 12, the user uses their thumb and forefinger to press the button 52 against both ends, pushing the button 52 to reciprocate along the second axis A2, allowing for quick switching between the first and second positions. The shifting action can be completed with one hand, making the operation simple and providing a good user experience. In addition, placing the button 52 between the transmission assembly 3 and the switch assembly 4 reduces the height occupied by the main body 11 in the vertical direction, allowing for normal use in confined spaces and improving the performance of the drill 100 during edge-trimming operations.

[0046] In this embodiment, the control component 6 is placed inside the grip 12 and located below the switch component 4. The control component 6 and the button 52 are located on the upper and lower sides of the switch component 4, respectively. This arrangement makes the component arrangement of the electric drill 100 more reasonable.

[0047] Alternatively, the control component 6 is housed within the main body 11, and the control component 6 is located behind the motor assembly 2.

[0048] In this embodiment, the shifting element 51 extends circumferentially along the internal gear ring 31 and includes a U-shaped connecting portion 511, a pair of connecting arms 512 disposed at both ends of the connecting portion 511, and a pivot portion 513 located between the connecting portion 511 and the connecting arms 512. The pair of connecting arms 512 are connected to both sides of the internal gear ring 31, and the pivot portion 513 is mounted to the housing 1. The button 52 moves along the second axis A2, causing the shifting element 51 to rotate around the pivot portion 513, and driving the internal gear ring 31 to move along the first axis A1, thereby realizing the free switching between two gears.

[0049] Please combine Figure 8 As shown, the intermediate plate 54 is located between the shift element 51 and the button 52. The intermediate plate 54 extends along the direction of the second axis A2 and is approximately parallel to the button 52. The intermediate plate 54 is provided with a through guide groove 541, and the guide member 55 moves within the guide groove 541. The intermediate plate 54 is fixed, and the guide groove 541 guides the movement of the guide member 55.

[0050] Furthermore, since the second axis A2 is perpendicular to the first axis A1, in order to convert the movement of the button 52 along the direction of the second axis A2 into the movement of the internal gear ring 31 along the direction of the first axis A1, the extension direction of the guide groove 541 is set at an angle to the second axis A2.

[0051] Please combine Figure 9As shown, the button 52 includes a pair of protruding ribs 521 extending from the end face toward the middle plate 54. The extending directions of the pair of protruding ribs 521 are parallel to each other and perpendicular to the second axis A2. The guide 55 is located between the pair of protruding ribs 521. The guide 55 abuts against the protruding ribs 521 and slides along the sidewalls of the pair of protruding ribs 521.

[0052] In this embodiment, the guide 55 includes a pawl 551 connecting to the shift element 51 and a guide post 552 extending downward from the bottom of the pawl 551. The guide post 552 extends through the guide groove 541 and abuts against the rib 521. Furthermore, the pawl 551 is U-shaped, and the connecting portion 511 of the shift element 51 is at least partially located within the pawl 551.

[0053] In this embodiment, the aforementioned claw 551 and guide post 552 are integrally formed.

[0054] Please see Figure 5 and Figure 7 As shown, the stop portion 53 is connected to the lower side of the button 52 and moves as the button 52 moves. The stop portion 53 is located between the button 52 and the trigger 42.

[0055] Furthermore, the aforementioned stop portion 53 extends downward from the lower end of the button 52, and the stop portion 53 and the button 52 are integrally formed.

[0056] Please combine Figure 10 and Figure 11 As shown, the shift assembly 5 also includes an adjustment plate 56 connected to the button 52. The adjustment plate 56 protrudes from the stop portion 53 toward the switch element 41. The adjustment plate 56 has a pivot point 561 connected to the switch element 41. When the user moves the button 52, the adjustment plate 56 will rotate around the pivot point 561. During the rotation, the adjustment plate 56 can generate different signals to the switch element 41. These different signals can be used to realize functions such as forward and reverse switching of the motor assembly 2.

[0057] Furthermore, a spring can be provided at the connection point between the pivot point 561 of the aforementioned adjustment plate 56 and the switch element 41 to provide a better tactile feel when the user moves the button 52.

[0058] Please see Figures 10 to 13As shown, the trigger 42 includes a base 421, a limiting part 422 disposed on the base 421, and a pressing part 425 for the user to press. The pressing part 425 and the limiting part 422 are located on different end faces of the base 421. Specifically, the pressing part 425 is located on the side of the base 421 away from the switching element 41, while the limiting part 422 is located on the upper side of the base 421. The limiting part 422 is disposed adjacent to the stop part 53, and the stop part 53 is located on the path of the pressing stroke of the trigger 42. This means that during the pressing process, the limiting part 422 abuts against the stop part 53, and the trigger 42 cannot be pressed to the full pressing stroke (i.e., cannot be pressed all the way down). Therefore, the maximum output speed of the motor assembly 2 is limited. In actual use, the output end 20 can output a lower force at the speed required by the user to meet the needs of different working scenarios.

[0059] In this embodiment, the stop portion 53 is located between the button 52 and the base 421, and the stop portion 53 is at least partially located between the trigger 42 and the switch element 41.

[0060] In this embodiment, the end face of the base 421 facing the stop 53 is provided with a slide rail, that is, the slide rail is provided on the upper side of the base 421, and the stop 53 moves in the slide rail. The limiting part 422 is located in the slide rail, so that the trigger 42 cannot be pressed to the full pressing stroke (i.e., cannot be pressed all the way down), thereby limiting the maximum output speed of the motor assembly 2.

[0061] Specifically, the aforementioned slide rail includes a first slide rail 423 corresponding to a first position and a second slide rail 424 corresponding to a second position, with a limiting part 422 disposed in at least one of the first slide rail 423 and the second slide rail 424. In the first state, the stop part 53 moves within the first slide rail 423; in the second state, the stop part 53 moves within the second slide rail 424.

[0062] Furthermore, the aforementioned limiting part 422 is located in the second slide rail 424. Since the first state is the low-speed state, the first state corresponds to the first position and the first slide rail 423; the second state is the high-speed state, the second state corresponds to the second position and the second slide rail 424. Based on the theoretical model of planetary gears, the reduction ratio of each stage is 1 + Z3 / Z1, where Z3 is the number of teeth of the internal gear ring and Z1 is the number of teeth of the sun gear. The reduction ratio of each stage of planetary gears is not less than 3. If the ratio of the rotational speed in the high-speed state to the rotational speed in the low-speed state needs to be less than 3, traditional planetary gear reduction devices are basically unable to achieve this.

[0063] In this embodiment, by placing the limiting part 422 within the second slide rail 424, when the user presses the trigger 42 in the high-speed mode, the limiting part 422 abuts against the stop part 53, preventing the trigger 42 from being pressed to its full pressing stroke (i.e., not being able to be pressed all the way down). Therefore, the maximum output speed of the motor assembly 2 is limited, and even in the high-speed mode, the user can obtain a lower speed force. This overcomes the limitation of traditional planetary gear reduction devices that cannot achieve a speed ratio of less than 3 between the high-speed mode and the low-speed mode, effectively meeting the diverse work needs of users.

[0064] In this embodiment, the second slide rail 424 has a limiting part 422, so the length of the second slide rail 424 is less than the length of the first slide rail 423; and the length settings of the first slide rail 423 and the second slide rail 424 can be adaptively adjusted based on the actual requirements of the output speed.

[0065] This invention is not limited to the specific embodiments described above. Those skilled in the art will readily understand that many other alternatives to the handheld power tool of this invention can be developed without departing from the principles and scope of the invention. The scope of protection of this invention is defined by the claims.

Claims

1. A handheld power tool, comprising a housing, a motor assembly and a transmission assembly mounted on the housing, a switch assembly connected to the motor assembly, a shift assembly connected to the transmission assembly, and an output terminal driven by the transmission assembly, wherein the switch assembly includes a switch element mounted on the housing and a trigger for actuating the switch element, and the shift assembly includes a shift element connected to the transmission assembly and a button for moving the shift element; characterized in that: The switching assembly is a speed control switch, and the output speed of the motor assembly is adjusted by the pressing stroke of the trigger. The trigger includes a base and a limiting part disposed on the base. The shifting assembly includes a stop part corresponding to the limiting part. The stop part is connected to the button and moves with the movement of the button. The limiting part abuts against the stop part to limit a portion of the stroke of the stop part. The shifting assembly includes a guide member connected between the shifting element and the button and a guide groove for the guide member to move. The motor assembly has a first axis extending in a front-rear direction. The button moves along a second axis direction perpendicular to the first axis. The extension direction of the guide groove is angled to the second axis.

2. The handheld power tool according to claim 1, characterized in that: The stop portion is located between the button and the base, and the stop portion is at least partially located between the trigger and the switch element.

3. The handheld power tool according to claim 1, characterized in that: The output terminal includes a first state and a second state operating at different speeds. The transmission assembly includes a movable internal gear ring. The button includes a first position corresponding to the first state and a second position corresponding to the second state. The shifting element is connected to the internal gear ring. Moving the button switches between the first state and the second state.

4. The handheld power tool according to claim 3, characterized in that: The end face of the base facing the stop is provided with a slide rail. The stop moves within the slide rail, and the limiting part is located within the slide rail, so that the trigger cannot be pressed all the way down, thereby limiting the maximum output speed of the motor assembly.

5. The handheld power tool according to claim 4, characterized in that: The slide rail includes a first slide rail corresponding to the first position and a second slide rail corresponding to the second position, and the limiting part is provided in at least one of the two slide rails.

6. The handheld power tool according to claim 5, characterized in that: The first state is a low speed gear, and the second state is a high speed gear. In the first state, the stop part moves within the first slide rail; in the second state, the stop part moves within the second slide rail, and the limiting part is located in the second slide rail.

7. The handheld power tool according to claim 6, characterized in that: The shifting assembly includes an intermediate plate fixed to the housing, and the guide groove passes through the intermediate plate.

8. The handheld power tool according to claim 7, characterized in that: The button includes a raised rib extending from the end face toward the middle plate, and the guide abuts against the raised rib.

9. The handheld power tool according to claim 8, characterized in that: The guide includes a pawl connected to the shifting element and a guide post extending downward from the bottom of the pawl, the guide post extending through the guide groove and abutting against the rib.

Images