Power tool with electromechanical speed selection switch

Abstract

The utility model discloses an electric tool with an electromechanical speed selection switch. Comprising a housing, a motor supported within the housing, a transmission operably coupled to the motor, a transmission switchable between a low speed high torque mode and a high speed low torque mode, a spindle configured to receive torque from the motor through the transmission, comprising a speed selector movable to switch an actuator of the transmission between a low speed high torque mode and a high speed low torque mode, a shaft movable in response to movement of the actuator, a magnet coupled to the shaft, and a controller configured to change an operating speed of the motor based on a detected magnet position.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 683,123, filed August 14, 2024, and U.S. Provisional Patent Application No. 63 / 623,066, filed January 19, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This utility model relates to power tools, and more specifically to core drills. Background Technology

[0004] Core drills are typically used to remove cylindrical material from a workpiece. Utility Model Content

[0005] In some aspects, the technology described in this utility model relates to a power tool, comprising: a housing; a motor supported within the housing; a transmission operatively coupled to the motor, the transmission being switchable between a low-speed, high-torque mode and a high-speed, low-torque mode; a spindle configured to receive torque from the motor via the transmission; a speed selector including an actuator, a shaft, and a magnet, the actuator being movable to switch the transmission between the low-speed, high-torque mode and the high-speed, low-torque mode, the shaft being movable in response to movement of the actuator, and the magnet being coupled to the shaft; and a controller configured to change the operating speed of the motor based on a detected magnet position.

[0006] In some aspects, the present invention relates to an electric tool comprising: a housing; a motor supported within the housing; a gear housing supported within the housing; a transmission mechanism disposed within the gear housing and operatively coupled to the motor, the transmission mechanism being switchable between a low-speed, high-torque mode and a high-speed, low-torque mode; a spindle configured to receive torque from the motor via the transmission mechanism; an actuator movable to switch the transmission mechanism between the low-speed, high-torque mode and the high-speed, low-torque mode; a cam coupled to the actuator and movable with the actuator; a shaft configured to be axially displaced by movement of the cam; and a controller configured to change the operating speed of the motor in response to displacement of the shaft, wherein the cam and the shaft are disposed between the housing and the gear housing.

[0007] The present invention relates to an electric tool, comprising: a housing; a motor supported within the housing; a transmission mechanism operatively coupled to the motor, the transmission mechanism including a first gear, a second gear, and a shift collar configured to engage the first gear or the second gear; a spindle configured to receive torque from the motor via the transmission mechanism; an actuator rotatable to move the shift collar to engage the first gear or the second gear; a shaft configured to be axially displaced by movement of a cam; and a sensing component configured to detect the position of a magnet supported by the shaft to electronically change the operating speed of the motor.

[0008] Other features and aspects of this invention will become apparent from careful reading of the following detailed description and accompanying drawings. Attached Figure Description

[0009] Figure 1 This is a perspective view of a core drill according to an embodiment of the present invention, with the tool head coupled to the core drill.

[0010] Figure 2 yes Figure 1 A 3D diagram of a core drill without a tool head.

[0011] Figure 3 It is along Figure 1 The line 3-3 in the middle is cut off Figure 1 A cross-sectional view of the core drill.

[0012] Figure 4 It includes the electromechanical speed switch according to the embodiments of this utility model. Figure 1 A top view of the core drill, with the electromechanical speed switch set in the first position.

[0013] Figure 5 yes Figure 1 An enlarged side view of the core drill. Figure 4 The electromechanical speed switch includes an actuator knob in the first position.

[0014] Figure 6 yes Figure 5 A cross-sectional view of an electromechanical speed switch, with a portion of it removed.

[0015] Figure 7 yes Figure 1 An enlarged side view of the core drill. Figure 5 The actuator knob is set to the second position.

[0016] Figure 8 yes Figure 1 A top view of the coring drill. Figure 4 The electromechanical speed switch is in the second position.

[0017] Figure 9 yes Figure 8 A cross-sectional view of an electromechanical speed switch, with a portion of it removed.

[0018] Figure 10 yes Figure 1 An enlarged side view of the core drill. Figure 5 The actuator knob is set to the third position.

[0019] Figure 11 yes Figure 1 A top view of the coring drill. Figure 4 The electromechanical speed switch is in the third position.

[0020] Figure 12 yes Figure 11 A cross-sectional view of an electromechanical speed switch, with a portion of it removed.

[0021] Figure 13 yes Figure 1 An enlarged view of the core drill. Figure 5 The actuator knob is set to the fourth position.

[0022] Figure 14 yes Figure 1 A top view of the coring drill. Figure 4 The electromechanical speed switch is in the fourth position.

[0023] Figure 15 yes Figure 14 A cross-sectional view of an electromechanical speed switch, with a portion of it removed.

[0024] Figure 16 This is a cross-sectional view of an electromechanical speed switch according to another embodiment of the present invention.

[0025] Figure 17 It is shown in Figure 4 A graph showing the change in magnetic flux of the shaft of an electromechanical speed switch at various linear travel distances.

[0026] Figure 18 yes Figure 4 A diagram illustrating the magnetic flux of the magnet in an electromechanical speed switch.

[0027] Figure 19 This is a perspective view of a partially removed core drill, which includes an electromechanical speed switch according to another embodiment of the present invention.

[0028] Figure 20 yes Figure 20 A top view of the coring drill.

[0029] Figure 21 yes Figure 20 A magnified 3D view of the core drill.

[0030] Figure 22 yes Figure 20 A top-down, three-dimensional magnified view of the core drill.

[0031] Figure 23 yes Figure 20 A magnified side view of the core drill.

[0032] Before explaining any embodiment of this utility model in detail, it should be understood that the disclosure of this utility model is not limited to the details of the construction and arrangement of the components described in the following description or shown in the drawings. This utility model can have other embodiments and can be practiced or implemented in various ways. Furthermore, it should be understood that the wording and terminology used herein are for illustrative purposes and should not be considered restrictive. Detailed Implementation

[0033] Figure 1 A power tool in the form of a core drill 10 is shown. The core drill 10 includes a housing 14, which has a motor housing portion 18 and a drive housing portion 20. The motor 22 is disposed within the motor housing portion 18 of the housing 14. Figure 3 The illustrated embodiment uses a brushless DC motor. In other embodiments, the core drill 10 may include other types of motors. The illustrated core drill 10 is cordless and includes a battery 23 that supplies power to the motor 22. In other embodiments, the core drill 10 may be a corded tool configured to receive power from a wall socket or other remote power source.

[0034] The core drill 10 further includes a main handle or first handle 24 and an auxiliary handle or second handle 26. The first handle 24 is coupled to and located at the rear of the motor housing portion 18. The first handle 24 is configured to be gripped by a user during operation of the core drill 10. The second handle 26 is removably coupled to the drive housing portion 20. A trigger 28 is disposed on the first handle 24 and actuates the motor 22 when pressed by the user. The trigger 28 may be, for example, a speed-changing trigger operable to alter the operating speed of the motor 22 based on the degree to which the trigger 28 is pulled. In other embodiments, the trigger 28 may be an on / off trigger operable to actuate the motor 22 to a preset speed. In either case, the trigger 28 has an initial position and a fully actuated position, in which the motor 22 is de-energized and in the fully actuated position, the motor 22 is operable at maximum rotational speed for a specific operating setting of the core drill 10, as described in more detail below.

[0035] See Figure 3 and 4 The core drill 10 includes a spindle 30, which is rotatable about a rotation axis A1 in response to torque received from a motor 22. A tool head 32 (e.g., a core drill bit); Figure 1The tool head 32 can be coupled to the threaded end 31 of the spindle 30 for rotation with the spindle 30 to perform work on a workpiece (e.g., core drilling). In the illustrated embodiment, a locking collar 33 is provided to allow the user to apply a preload to the threaded connection between the spindle 30 and the tool head 32 to secure the tool head 32. The locking collar 33 can also be actuated to release the preload to facilitate removal of the tool head 32.

[0036] The drive assembly 34 is disposed within the drive housing portion 20 of the housing 14 and is configured to transmit torque from the output shaft 38 of the motor 22 to the main shaft 30. The drive assembly 34 shown includes a multi-speed transmission 42 having a first gear or low-speed gear 44a with a first spline portion 48a and a second gear or high-speed gear 44b with a second spline portion 48b. The low-speed gear 44a and high-speed gear 44b are fitted onto the rear end portion of the main shaft 30 (opposite to the threaded end 31 of the main shaft 30) and are rotatable relative to the main shaft 30. The low-speed gear 44a and high-speed gear 44b mesh with and are continuously driven by corresponding first and second drive gears (not shown). The first and second drive gears are fixed to an intermediate shaft (not shown). In the illustrated embodiment, a pinion 50 integrally formed on the output shaft 38 meshes with an intermediate gear 51 (e.g., a helical gear) coupled to the intermediate shaft (not shown) for common rotation. Figure 3 The intermediate gear 51 can be coupled to the intermediate shaft in any number of different ways (e.g., key and keyway arrangement, interference fit, spline fit, etc.). In some embodiments, the intermediate gear 51 can be coupled to the intermediate shaft via a clutch mechanism.

[0037] Shift collar 72 is coupled to rotate with the main shaft 30 and positioned between the low-speed gear 44a and the high-speed gear 44b. As described in more detail below, shift collar 72 is movable along axis A1 to selectively engage either the low-speed gear 44a or the high-speed gear 44b, thereby coupling the selected gears 44a, 44b to rotate with the main shaft 30. In this way, shift collar 72 selects which of the gears 44a, 44b drives the main shaft 30. The low-speed gear 44a has a relatively larger number of teeth than the high-speed gear 44b. Therefore, in the illustrated embodiment, shift collar 72 can be displaced to a first position in which shift collar 72 engages the low-speed gear 44a to define a low-speed-high torque mode of drive assembly 34. The low-speed-high torque mode provides a first gear ratio between output shaft 38 and main shaft 30. The shift collar 72 is displaceable to a second position in which it engages the high-speed gear 44b to define a high-speed-low torque mode for the drive assembly 34. The high-speed-low torque mode provides a second gear ratio, less than the first gear ratio, between the output shaft 38 and the main shaft 30. In some embodiments, the first gear ratio may be between 10:1 and 20:1, and the second gear ratio may be between 3:1 and 8:1. In some embodiments, the first gear ratio may be between 12:1 and 18:1. In some embodiments, the first gear ratio may be between 14:1 and 17:1. In some embodiments, the second gear ratio may be between 4:1 and 7:1. In some embodiments, the second gear ratio may be between 5:1 and 6:1. In some embodiments, the first gear ratio may be at least twice the second gear ratio. In some embodiments, the first gear ratio may be at least 2.5 times the second gear ratio. In some embodiments, the first gear ratio may be at least three times the second gear ratio. In some embodiments, the transmission 42 may be configured to switch between more than two gear ratios.

[0038] The core drill 10 also includes a speed selector or electromechanical speed switch 52, which has an actuator knob 56, a rod 60 coupled to and extending from the actuator knob 56, and a cam disk 64 also coupled to the actuator knob 56. The actuator knob 56 is disposed along the drive housing portion 20 and configured to be rotated by the user to adjust the output speed of the spindle 30. As the actuator knob 56 rotates, a spring-biased pin 66 engages with four stop recesses 68a-d defined in the housing 14 of the core drill 10. Figure 5 The interaction is one of the four different output speeds defined by the stop recesses 68a-d, at which the core drill 10 can operate.

[0039] Figure 6A shaft 70 and a sensing assembly 76 are shown disposed within a housing 14 of a core drill 10. The shaft 70 is formed with a pin-shaped or tapered end 69 that engages with a cam disk 64 to allow axial displacement of the shaft 70 within the housing 14. A recess 80 is defined within the shaft 70 and configured to support and retain a magnet 84. The sensing assembly 76 includes a Hall sensor plate 88 and a Hall effect sensor 92 disposed on the Hall sensor plate 88. In other embodiments, the Hall effect sensor 92 may be remote and wired to another separate printed circuit board (PCB). The Hall effect sensor 92 is configured to detect the position of the magnet 84 as the shaft 70 moves within the housing 14. The sensing assembly 76 also includes a ferrous metal component 78 disposed along the Hall sensor plate 88 to make the magnetic flux of the magnet 84 more concentrated on the top side of the magnet 84.

[0040] When the actuator knob 56 is rotated, the lever 60 is configured to move the shift collar 72 of the transmission 42 to adjust the gear ratio of the transmission 42. Specifically, the lever 60 pushes the first plate 71a to the right, thereby energizing the spring 74 on the opposite side of the second plate 71b. When the shift collar 72 is properly aligned with the low-speed gear 44a, the shift collar 72 moves onto the first spline portion 48a to engage the low-speed gear 44a. When the shift collar 72 is not aligned, the stored energy of the spring 74 energizes the second plate 71b and the shift collar 72. Then, when the low-speed gear 44a moves to align with the shift collar 72, the second plate 71b and the shift collar 72 move. Thus, the user can set the desired position of the actuator knob 56 without manipulating the spindle 30.

[0041] The cam disk 64 is configured to rotate together with the actuator knob 56, which causes the shaft 70 to shift to allow movement of the magnet 84. The movement of the magnet 84 adjusts the output of the Hall effect sensor 92 to deliver different current levels to the motor 22, thereby electronically changing the speed of the motor 22 without requiring a change in the gear ratio of the transmission 42. The magnetic flux generated by the magnet 84 and detected by the Hall effect sensor 92... Figure 18 As shown in the figure, and Figure 17 The magnetic flux detected by Hall effect sensor 92 varies based on the displacement of shaft 70 and magnet 84.

[0042] During operation, when the actuator knob 56 is set to the first position ( Figure 6When the trigger 28 is fully depressed, the shift collar 72 moves to engage the low-speed gear 44a, thereby placing the drive assembly 34 in a low-speed-high-torque mode. The magnet 84 is positioned in the first right position, which allows the Hall effect sensor 92 to read the positive magnetic field and the controller (which may be implemented as, for example, a microprocessor, machine-readable non-transitory memory, and switching electronics—such as a FET—for controlling the power delivery to the motor 22) to operate the motor 22 at a first motor speed (e.g., 16000 RPM–17000 RPM in some embodiments). Therefore, the first position of the actuator knob 556 defines a first speed setting for the core drill 10. In some embodiments, when the core drill 10 is in the first speed setting, the spindle 30 can rotate at a maximum speed between 800 RPM and 1200 RPM, between 900 RPM and 1100 RPM, or approximately 1000 RPM.

[0043] To increase the speed of the spindle 30, the actuator knob 56 can be rotated (e.g., counterclockwise) to set it to a second position. Figure 7-9 In the second position, the shift collar 72 remains engaged with the low-speed gear 44a, which prevents a change in the gear ratio of the transmission 42. As the cam disc 64 rotates with the actuator knob 56, the shaft 70 shifts, causing the magnet 84 to move in the first direction or to the left. When the trigger 28 is fully depressed, the Hall effect sensor 92 reads the neutral magnetic field and communicates with the controller to electronically change the speed of the motor 22 from the first speed to a second motor speed greater than the first speed (e.g., 26,000-27,000 RPM). Thus, the second position of the actuator knob 56 defines a second speed setting for the core drill 10. In some embodiments, when the core drill 10 is in the second speed setting, the spindle 30 can rotate at a maximum speed between 1400 RPM and 1800 RPM, between 1500 RPM and 1700 RPM, or approximately 1600 RPM.

[0044] When the actuator knob 56 is rotated further counterclockwise to the third position ( Figure 10-12When the shift collar 72 moves to engage the high-speed gear 44b and change the gear ratio of the transmission 42 to a high-speed-low torque mode, the shaft 70 shifts, causing the magnet 84 to move further to the left. When the trigger 28 is fully depressed, the Hall effect sensor 92 reads the negative magnetic field, and the motor 22 operates at a third motor speed (e.g., 14,500 RPM-15,500 RPM) less than the first speed. Therefore, the third position of the actuator knob 56 defines the third speed setting of the core drill 10. In some embodiments, the third motor speed is less than the first and second motor speeds. In some embodiments, the third motor speed may be equal to the first motor speed. In some embodiments, the third motor speed may be greater than the first motor speed and less than the second motor speed. In some embodiments, when the core drill 10 is in the third speed setting, the spindle 30 can rotate at a maximum speed between 2,300 RPM and 2,900 RPM, between 2,500 RPM and 2,700 RPM, or about 2,600 RPM.

[0045] When the actuator knob 56 is rotated further to the fourth position ( Figure 13-15 When the shift collar 72 remains engaged with the high-speed gear 44b, the gear ratio of the transmission 42 remains unchanged. Similarly, the shaft 70 is displaced by the rotation of the cam disc 64, causing the magnet 84 to move in the second direction or to the right. When the trigger 28 is fully depressed, the Hall effect sensor 92 reads the neutral magnetic field, and the motor 22 is operated by the controller at a fourth motor speed (e.g., 26000 RPM-27000 RPM). Therefore, the fourth position of the actuator knob 56 defines the fourth speed setting of the core drill 10. In some embodiments, the fourth motor speed is greater than the first and third motor speeds. In some embodiments, the fourth motor speed may be equal to the second motor speed. In some embodiments, the fourth motor speed may be greater than or less than the second motor speed. In some embodiments, when the core drill 10 is in the fourth speed setting, the spindle 30 can rotate at a maximum speed between 3500 RPM and 5500 RPM, between 4000 RPM and 5000 RPM, or approximately 4570 RPM.

[0046] It has been found that the first, second, third, and fourth speed settings described above provide optimal performance for different sizes of core drill bits 32. See also Figure 2The core drill 10 shown includes markings 89 around the actuator knob 56 at positions corresponding to four respective speed settings. Markings 89 indicate the nominal size or size range of various core drill bits 32 that can be attached to the spindle 30. In some embodiments, markings 89 may indicate a first position of the actuator knob 56 and a first speed setting corresponding to a core drill bit 32 with a diameter between 3 and 4 inches, a second position of the actuator knob 56 and a second speed setting corresponding to a core drill bit 32 with a diameter between 2 and 3 inches, a third position of the actuator knob 56 and a third speed setting corresponding to a core drill bit 32 with a diameter between 1 and 2 inches, and a fourth position of the actuator knob 56 and a fourth speed setting corresponding to a core drill bit 32 with a diameter less than 1 inch. In this way, the electromechanical speed switch 52 provides the core drill 10 with four easily accessible speed settings optimized for different drill bit sizes, while requiring only two mechanical gear positions. However, the electromechanical speed switch 52 described above can be incorporated into other types of power tools.

[0047] See you again Figure 1 The core drill 10 includes a fluid distribution system 93. The fluid distribution system 93 has a first connector 94, a second connector 95 coupled to a motor housing portion 18, and a control valve 96 also coupled to the motor housing portion 18. The first connector 94 can be attached to a supply line (not shown) to supply fluid (e.g., water) to the fluid distribution system 93 from an external source (not shown). A delivery line 97 extends from the second connector 95 into the drive housing portion 20 to connect to a third connector 98 of the fluid distribution system 93. Figure 3 A control valve 96 is disposed between a first connector 94 and a second connector 95 to regulate fluid flow from the supply line to the delivery line 97. The control valve 96 has a handle 99 movable by a user between a first position and a second position. In the first position, the control valve 96 is in a closed state, preventing fluid flow from the first connector 94 to the second connector 95. In the second position, the control valve 96 is in an open state, allowing fluid flow from the first connector 94 to the second connector 95. Therefore, during the open state, fluid is allowed to flow through the delivery line 97 and to the spindle 30 for cooling, lubrication, and dust removal of the tool head 32.

[0048] Figure 16 It shows that it can be combined with Figure 1 Another electromechanical speed switch 152 is used in the core drill 10. The electromechanical speed switch 152 can also be integrated into other types of power tools. The electromechanical speed switch 152 is similar to... Figure 1-15 The electromechanical speed switch 52; therefore, the same structure will be identified by the same reference numerals plus "100". This will be discussed below. Figure 16 Electromechanical speed switch 152 and Figure 1-15The difference between electromechanical speed switches.

[0049] The electromechanical speed switch 152 includes a cam disk 156 and a shaft 170. The shaft 170 is formed with a T-shaped end 202, which is configured to engage with the cam disk 156 to allow axial displacement of the shaft 170 within the housing 14. Compared to the shaft 70, the T-shaped end 202 of the shaft 170 provides a larger contact area between the shaft 170 and the cam disk 156 at different positions of the shaft 170 when the cam disk 156 is rotated by an actuator knob (not shown).

[0050] Figure 19-23 Another embodiment of the core drill 310 is shown. The core drill 310 is similar to... Figure 1-15 The core drill 10; therefore, the same structure will be identified by the same reference numerals plus "300". This will be discussed below. Figure 19-23 Core drill 310 and Figure 1-15 The differences between the core drills 10; however, it should be understood that the features and elements of the core drill 10 can be incorporated into the core drill 310, and vice versa.

[0051] See Figure 19 and 20 The core drill 310 includes a housing 314, a portion of which is in Figure 20-23 As shown in the figure. The housing 314 is made of a first material such as plastic or composite material and can be defined by mating clamshell-type housing halves. The housing 314 shown has a motor housing portion (surrounding a motor 322 of the core drill 310) and a drive housing portion 320 (surrounding a drive assembly 334 of the core drill 310). The drive assembly 334 is configured to transmit torque from the output shaft 338 of the motor 322 to the spindle 330. A tool head (e.g., a core drill bit; not shown) can be coupled to the spindle 330 to rotate with the spindle 330 to perform work (e.g., drilling) on ​​a workpiece. The drive assembly 334 includes a multi-speed transmission 342, which can be similar to the one referenced above. Figure 1-15 The transmission device 42 is described above. A multi-speed transmission device 342 is disposed within a gear housing 402, which is in turn supported within a drive housing portion 320 of a housing 314. In the illustrated embodiment, the gear housing 402 is made of a second material (e.g., a metal such as steel, aluminum, or magnesium) different from the first material of the housing 314.

[0052] See Figure 21-22The core drill 310 shown further includes an electromechanical speed switch 352, a shaft 370, and a sensing assembly 376. The speed switch 352 has an actuator knob 356 and a cam disk 364 coupled to the actuator knob 356 for rotation therewith. The actuator knob 356 is configured to be rotated by a user to adjust the output speed of the spindle 330. The cam disk 364, shaft 370, and sensing assembly 376 are arranged outside the gear housing 402, thus positioned between the gear housing 402 and the housing 314. In other embodiments, the position of the speed switch 352, shaft 370, and sensing assembly 376 along the housing 314 of the core drill 310 may vary.

[0053] See Figure 23 The shaft 370 is formed with a T-shaped end 404, which is configured to mate with the cam disk 364 to allow axial displacement of the shaft 370 in response to rotation of the cam disk 364. More specifically, the T-shaped end 404 engages a circular protrusion 408 extending eccentrically from the disk portion 412 of the cam disk 364. A recess (not shown) is defined within the shaft 370 and is configured to support and retain the magnet 384. Figure 22 The sensing assembly 376 includes a Hall sensor board 388 and a Hall effect sensor 392. The Hall sensor board 388 is mounted on a bracket 416 fixed to the gear housing 402. The Hall effect sensor 392 is disposed on the Hall sensor board 388. In other embodiments, the Hall effect sensor 392 may be remote and wired to another separate printed circuit board (PCB). The Hall sensor 392 is configured to detect the position of the magnet 384 as the shaft 370 moves within the housing 314.

[0054] Cam disk 364 is configured to rotate together with actuator knob 356. When actuator knob 356 rotates, cam disk 364 also rotates, causing shaft 370 to shift to move magnet 384. The movement of magnet 384 is detected by changes in the output signal of Hall effect sensor 392, and the controller of core drill 310 is configured to deliver different voltage and / or current levels (including but not limited to PWM signals with different duty cycles, etc.) to motor 322 to electrically change the speed of motor 322 without changing the gear ratio of the transmission. In the illustrated embodiment, rotation of actuator knob 356 is also configured to, in a manner similar to the above-described combination... Figure 1-15 The gear ratio of the transmission device 342 is adjusted in the manner described in the core drill 10.

[0055] During the rotation of the cam disk 364, the spring bias pin 366 ( Figure 20It also interacts with the cam disk 364. More specifically, the spring-biased pin 366 interacts with one of a plurality of stop recesses (not shown) defined within the cam disk 364. The plurality of stop recesses define different switching positions corresponding to different output speeds at which the core drill 310 can operate. In the illustrated embodiment, the spring-biased pin 366 extends from a protrusion 420 formed on the gear housing 402. In other embodiments, the spring-biased pin 366 may extend from the actuator knob 356.

[0056] Although this disclosure has been described in detail with reference to certain preferred embodiments, variations and modifications are possible within the scope and spirit of one or more independent aspects of the disclosure.

[0057] Various features and aspects of this utility model are described in the claims.

Claims

1. A power tool, characterized in that, include: case; The motor is supported within the housing; A transmission device operably coupled to the motor, the transmission device being switchable between a low-speed, high-torque mode and a high-speed, low-torque mode; A spindle configured to receive torque from the motor via the transmission device; A speed selector, the speed selector including an actuator, a shaft and a magnet, the actuator being movable to switch the transmission between a low-speed, high-torque mode and a high-speed, low-torque mode, the shaft being movable in response to movement of the actuator, and the magnet being coupled to the shaft; and A controller configured to change the operating speed of the motor based on the detected position of the magnet.

2. The power tool as described in claim 1, characterized in that, The speed selector further includes a cam disk coupled to and movable by the actuator, and the shaft is configured to be axially displaced by movement of the cam disk to change the operating speed of the motor.

3. The power tool as described in claim 2, characterized in that, The shaft has a recess that is configured to hold the magnet.

4. The power tool as described in claim 2 or 3, characterized in that, The shaft is formed to have a gradually narrowing end that engages with the cam disk.

5. The power tool as described in claim 2 or 3, characterized in that, The shaft is formed with a T-shaped end that engages with the cam disk.

6. The power tool as described in any one of claims 1-3, characterized in that, The actuator can move between a first position, a second position, a third position, and a fourth position, each position corresponding to a different maximum rotational speed of the spindle.

7. The power tool as described in claim 6, characterized in that, When the actuator is in the first position and the second position, the transmission device is in the low-speed high-torque mode, and wherein when the actuator is in the third position and the fourth position, the transmission device switches to the high-speed low-torque mode.

8. The power tool as claimed in claim 1, characterized in that, The transmission device has a shift collar that can be moved by the speed selector to engage a first gear or a second gear, thereby switching between the low-speed high-torque mode and the high-speed low-torque mode.

9. A power tool, characterized in that, include: case; The motor is supported within the housing; A gear housing, the gear housing being supported within the housing; A transmission device, which is disposed within the gear housing and operably coupled to the motor, is switchable between a low-speed, high-torque mode and a high-speed, low-torque mode; A spindle configured to receive torque from the motor via the transmission device; An actuator movable to switch the transmission between the low-speed high-torque mode and the high-speed low-torque mode; A cam, which is coupled to the actuator and is movable together with the actuator; A shaft, which is configured to be axially displaced by movement of the cam; and A controller configured to change the operating speed of the motor in response to displacement of the shaft. The cam and the shaft are disposed between the housing and the gear housing.

10. The power tool as claimed in claim 9, characterized in that, It further includes a sensing component disposed between the housing and the gear housing, the sensing component being configured to detect the position of a magnet supported by the shaft.

11. The power tool as claimed in claim 10, characterized in that, The sensing component includes a Hall effect sensor configured to output a signal to the controller.

12. The power tool as claimed in any one of claims 9-11, characterized in that, The shell is defined by interlocking clamshell-like halves.

13. The power tool as claimed in any one of claims 9-11, characterized in that, The housing is made of a first material, and the gear housing is made of a second material different from the first material.

14. The power tool as claimed in claim 13, characterized in that, The first material is plastic, and the second material is metal.

15. A power tool, characterized in that, include: case; The motor is supported within the housing; A transmission device operatively coupled to the motor, the transmission device including a first gear, a second gear, and a shift collar configured to engage the first gear or the second gear; A spindle configured to receive torque from the motor via the transmission device; An actuator, rotatable to move the shift collar to engage the first gear or the second gear; A shaft, configured to be axially displaced by rotation of the actuator; and A sensing component configured to detect the position of a magnet supported by the shaft, thereby electronically changing the operating speed of the motor.

16. The power tool as claimed in claim 15, characterized in that, The sensing component includes a sensor board and a Hall effect sensor disposed on the sensor board, the Hall effect sensor being configured to detect the position of the magnet.

17. The power tool as claimed in claim 15 or 16, characterized in that, The actuator can be rotated to a first position, in which the shift collar is moved to engage the first gear, such that the operating speed of the motor is a first motor speed.

18. The power tool as claimed in claim 17, characterized in that, The actuator can be rotated to a second position, in which the shift collar remains engaged with the first gear, and the shaft is axially displaced, thereby causing the magnet to move in a first direction, such that the operating speed of the motor is a second motor speed.

19. The power tool as claimed in claim 18, characterized in that, The actuator can be rotated to a third position, in which the shift collar moves to engage the second gear, and the shaft is axially displaced, thereby causing the magnet to move further in the first direction, such that the motor operates at a third motor speed.

20. The power tool as claimed in claim 19, characterized in that, The actuator can be rotated to a fourth position, in which the shift collar remains engaged with the second gear, and the shaft is axially displaced to move the magnet in a second direction, such that the motor operates at a fourth motor speed.

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