A DC speed regulating switch and a DC electric tool

Abstract

The present invention relates to the technical field of speed regulating switches, and specifically discloses a DC speed regulating switch and a DC electric tool. The switch includes a housing, a push rod assembly and a speed regulating assembly; the push rod assembly is movably mounted on the housing and can reciprocate along the extension direction of the push rod assembly; the speed regulating assembly is mounted in the housing and includes a motor and a current regulating member, wherein pushing the push rod assembly can make the speed regulating member be located at different positions, when located at the first position, the positive pole of the power supply is disconnected from the negative pole of the power supply, and the positive pole of the motor is short-circuited from the negative pole of the motor; when located at the second position, the positive pole of the power supply, the current regulating member, the motor and the negative pole of the power supply are electrically connected in sequence; when located at the third position, the current regulating member is short-circuited. The switch can complete the speed regulating operation of the motor by pushing the push rod assembly, which facilitates the operator to adjust the motor speed and improves the work efficiency; avoids the risk of failure due to abnormal connection status, and ensures the safety of the switch.

Description

Technical Field

[0001] The present invention relates to the technical field of speed regulating switches, and in particular to a direct current speed regulating switch and a direct current electric tool. Background Art

[0002] DC speed regulating switches are widely used in the field of DC power tools, such as electric drills, electric grinders, electric wrenches and electric screwdrivers. DC speed regulating switches mainly include a contact mechanism and a push rod mechanism for controlling the on and off of the contact mechanism.

[0003] In the prior art, in order to facilitate the adjustment of the working speed of the power tool using the DC speed regulating switch, it is often achieved by operating the DC speed regulating switch to adjust the motor speed. The brake operation and speed regulating operation of the existing DC speed regulating switch are respectively implemented by two different components. When the position of the switch component deviates due to problems such as component deformation or adhesion, the connection state of the line is abnormal, which can easily lead to a short circuit between the positive pole and the negative pole of the motor when the power supply is working, causing a large current to burn out the switch and other faults, posing a safety hazard to the DC power tool. Summary of the invention

[0004] The object of the present invention is to provide a DC speed regulating switch and a DC electric tool, so as to facilitate operators to adjust the motor speed while avoiding abnormal connection status.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A DC speed regulating switch comprises a shell, a push rod assembly and a speed regulating assembly; the push rod assembly is movably mounted on the shell and can reciprocate along the extension direction of the push rod assembly; the speed regulating assembly comprises a motor and a current regulating member, wherein pushing the push rod assembly can cause the speed regulating assembly to be located at different positions, wherein when located at a first position, the positive pole of a power source is disconnected from the negative pole of the power source, and the positive pole of the motor is short-circuited from the negative pole of the motor; when located at a second position, the positive pole of the power source, the current regulating member, the motor and the negative pole of the power source are electrically connected in sequence; and when located at a third position, the current regulating member is short-circuited.

[0007] Among them, the speed regulation component also includes a negative power supply plate, a positive connection plate, a positive power supply plate, a connecting moving touch plate and a speed-up moving touch plate, the connecting moving touch plate and the speed-up moving touch plate are respectively rotatably connected to the moving contact frame, and the moving contact frame and the negative power supply plate are respectively electrically connected to the two poles of the motor; a first moving contact is provided at one end of the connecting moving touch plate, and a second moving contact is provided at one end of the speed-up moving touch plate; a first static contact is provided on the positive connection plate, and a second static contact is provided on the positive power supply plate, the first moving contact is arranged opposite to the first static contact, and the second moving contact is arranged opposite to the second static contact, and the current regulating component is respectively electrically connected to the positive connection plate and the positive power supply plate.

[0008] Furthermore, the rotation plane where the connecting movable touch plate is located, the rotation plane where the accelerating movable touch plate is located, and the reciprocating direction of the push rod assembly are parallel to each other, and the connecting movable touch plate and the accelerating movable touch plate are both in contact with the push rod assembly.

[0009] Furthermore, the push rod assembly includes a telescopic spring and a push rod member connected to the telescopic spring and extending out of the shell, the push rod member crimping the connecting dynamic touch plate and the speed-up dynamic touch plate; the telescopic spring pushes the push rod member to a position away from the shell, so that the speed regulation assembly is located in the first position.

[0010] Furthermore, the connecting moving contact plate is an L-shaped piece, and a third moving contact is arranged at one end away from the first moving contact; the third moving contact is arranged opposite to the third static contact, and the third static contact is arranged on the negative plate of the power supply.

[0011] Preferably, the current regulating component is a field effect transistor, and the DC speed regulating switch also includes a circuit board, on which a negative resistor plate and a positive resistor plate are provided, and an electrical connecting plate is installed on the push rod component; the two ends of the electrical connecting plate can respectively abut against the negative resistor plate and the positive resistor plate, so that the negative resistor plate is electrically connected to the positive resistor plate; the negative plate of the power supply is electrically connected to the negative resistor plate, and the field effect transistor is electrically connected to the positive resistor plate, and an insulating plate is provided at one end of the negative resistor plate, and when the push rod component is located at a position away from the shell, the end of the electrical connecting plate close to the negative resistor plate abuts against the insulating plate.

[0012] Furthermore, a circuit board cavity and a speed regulating component cavity are provided in the shell, and a shell partition plate for separating the circuit board cavity and the speed regulating component cavity is provided in the middle of the shell, the circuit board is installed in the circuit board cavity, and the negative power supply plate, the positive connecting plate, the positive power supply plate, the current regulating component, the moving contact frame, the connecting moving touch plate and the speed-up moving touch plate are all installed in the speed regulating component cavity.

[0013] Furthermore, the DC speed regulating switch also includes a heat sink, the speed regulating component cavity includes a current regulating component cavity and a touch plate component cavity opened in the shell, the current regulating component cavity is opened on the shell, and the current regulating component is installed in the current regulating component cavity; the heat sink cover is arranged on the current regulating component cavity and is screwed to the shell.

[0014] Preferably, the speed regulating assembly further comprises a fuse, and the moving contact frame and the negative power plate are electrically connected to two poles of the fuse respectively.

[0015] A DC power tool comprises a DC power tool body and a DC speed regulating switch, wherein the DC speed regulating switch is the DC speed regulating switch described above.

[0016] Beneficial effects of the present invention:

[0017] With the help of the speed regulating component, the switch is configured so that when the push rod assembly moves to different positions, the electrical connection state of the switch is different; with the help of the current regulating component, the motor speed can be adjusted by changing the current. When the positive pole of the power supply is disconnected from the negative pole of the power supply, the positive pole of the motor is short-circuited with the negative pole of the motor, which avoids the short circuit between the positive pole of the motor and the negative pole of the motor when the power supply is working, ensuring the safety of the switch operation; when the current regulating component is short-circuited, the current passing through the motor increases, so that the speed of the motor is further increased. With the above settings, the operator can complete the adjustment of the motor speed by controlling the position of the push rod assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a circuit diagram of a DC speed regulating switch provided by an embodiment of the present invention;

[0019] Figure 2 is an exploded diagram of a DC speed regulating switch provided by an embodiment of the present invention;

[0020] Figure 3 is an exploded diagram of a speed regulating assembly provided by an embodiment of the present invention;

[0021] Figure 4 is a schematic structural diagram of a push rod assembly provided by an embodiment of the present invention;

[0022] Figure 5 is a structural schematic diagram of the second position of the speed regulating assembly provided by an embodiment of the present invention;

[0023] Figure 6 is a structural schematic diagram of the third position of the speed regulating assembly provided by an embodiment of the present invention;

[0024] Figure 7 It is a structural schematic diagram of the first position of the speed regulation component provided by an embodiment of the present invention.

[0025] In the figure:

[0026] 101, first side shell; 102, central shell; 103, second side shell; 110, circuit board cavity; 121, current regulating component cavity; 122, touch panel component cavity;

[0027] 200, push rod assembly; 210, telescopic spring; 220, push rod member; 221, electrical connection sheet; 222, push rod pressure head; 230, push rod washer; 240, push rod button;

[0028] 300, speed regulating assembly; 310, connecting moving contact plate; 311, first moving contact; 312, third moving contact; 320, speed-up moving contact plate; 321, second moving contact; 322, speed-up moving contact plate spring; 330, power supply negative plate; 331, third static contact; 340, positive connecting plate; 341, first static contact; 350, power supply positive plate; 351, second static contact; 352, first power supply positive plate; 353, second power supply positive plate; 360, current regulating member; 370, moving contact frame; 380, insurance member; 390, plate frame;

[0029] 400, circuit board; 410, negative electrode resistor plate; 411, insulating plate; 420, positive electrode resistor plate; 421, carbon film plate; 500, heat sink. DETAILED DESCRIPTION

[0030] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0033] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0034] like Figure 1 and Figure 2 As shown, this embodiment provides a DC speed regulating switch, including a housing, a push rod assembly 200 and a speed regulating assembly 300; the push rod assembly 200 is movably mounted on the housing and can reciprocate along the extension direction of the push rod assembly 200; the speed regulating assembly 300 includes a motor and a current regulating member 360, wherein pushing the push rod assembly 200 can make the speed regulating assembly 300 be located at different positions, when located at the first position, the positive pole of the power supply is disconnected from the negative pole of the power supply, and the positive pole of the motor is short-circuited with the negative pole of the motor; when located at the second position, the positive pole of the power supply, the current regulating member 360, the motor and the negative pole of the power supply are electrically connected in sequence; when located at the third position, the current regulating member 360 is short-circuited. With the setting of the speed regulating assembly 300, the switch is configured so that when the push rod assembly 200 moves to different positions, the electrical connection state of the switch is different; with the current regulating member 360, the motor speed can be adjusted by changing the current. When the positive pole and the negative pole of the power supply are disconnected, the positive pole and the negative pole of the motor are short-circuited, thereby avoiding the short-circuit between the positive pole and the negative pole of the motor when the power supply is working, and ensuring the safety of the switch operation; when the current regulating member 360 is short-circuited, the current passing through the motor increases, so that the speed of the motor is further increased. The above-mentioned setting enables the operator to complete the adjustment of the motor speed by controlling the position of the push rod assembly 200.

[0035] like Figure 2 and Figure 3As shown, the speed regulating assembly 300 also includes a negative power plate 330, a positive connecting plate 340, a positive power plate 350, a connecting moving touch plate 310 and a speed-up moving touch plate 320, the connecting moving touch plate 310 and the speed-up moving touch plate 320 are respectively rotatably connected to the moving contact frame 370, and the moving contact frame 370 and the negative power plate 330 are respectively electrically connected to the two poles of the motor; a first moving contact 311 is provided at one end of the connecting moving touch plate 310, and a second moving contact 321 is provided at one end of the speed-up moving touch plate 320; a first static contact 341 is provided on the positive connecting plate 340, and a second static contact 351 is provided on the positive power plate 350, the first moving contact 311 is arranged opposite to the first static contact 341, and the second moving contact 321 is arranged opposite to the second static contact 351, and the current regulating member 360 is respectively electrically connected to the positive connecting plate 340 and the positive power plate 350. With the above arrangement, it is easy to know that when the speed regulating assembly 300 is located in the second position, the first moving contact 311 abuts against the first static contact 341, and the second moving contact 321 is away from the second static contact 351. At this time, the positive plate 350 of the power supply, the current regulating member 360, the positive connecting plate 340, the connecting moving contact plate 310, the moving contact frame 370, the motor and the negative plate 330 of the power supply are electrically connected in sequence; when the speed regulating assembly 300 is located in the third position, the first moving contact 311 abuts against the first static contact 341, and the second moving contact 321 abuts against the second static contact 351. At this time, the speed-up moving contact plate 320 electrically connected to the moving contact frame 370 and the positive plate 350 of the power supply are directly electrically connected. This arrangement makes the positive connecting plate 340 and the current regulating member 360 short-circuited. According to the above arrangement, the current passing through the motor can be different by pushing the push rod assembly 200, thereby realizing the adjustment of the motor speed. The above arrangement has a simple structure, low cost and is easy to maintain.

[0036] Continue to refer Figure 1 When the speed regulating assembly 300 is located at the first position, the connecting moving touch plate 310 and the accelerating moving touch plate 320 are both disconnected, and the connecting moving touch plate 310 short-circuits the motor; when located at the second position, the connecting moving touch plate 310 is engaged, and the accelerating moving touch plate 320 is disconnected; when located at the third position, the accelerating moving touch plate 320 is engaged.

[0037] Continue to refer Figure 2 and Figure 3The negative power plate 330, the positive connecting plate 340, the positive power plate 350 and the moving contact frame 370 are all installed on the plate frame 390. The acceleration moving touch plate 320 is an L-shaped member. The second moving contact 321 is arranged at one end of the vertical plate of the acceleration moving touch plate 320. The plate frame 390 is also provided with an acceleration moving touch plate spring 322. One end of the acceleration moving touch plate spring 322 is connected to the plate frame 390, and the other end is clamped on the vertical plate of the acceleration moving touch plate 320. The acceleration moving touch plate spring 322 pulls the acceleration moving touch plate The touch plate 320 rotates toward the position where the power positive plate 350 is set; when the speed regulating assembly 300 is not in the third position, the push rod 220 presses the horizontal plate of the speed-up moving touch plate 320, and the second moving contact 321 is away from the second static contact 351; when the speed regulating assembly 300 is in the third position, the push rod 220 no longer presses the horizontal plate of the speed-up moving touch plate 320, and the speed-up moving touch plate spring 322 pulls the speed-up moving touch plate 320 to rotate, so that the second moving contact 321 abuts against the second static contact 351. The arrangement of the plate frame 390 makes the structure of the switch more compact; at the same time, the speed regulating assembly 300 is modularized, which facilitates the installation operation of the speed regulating assembly 300.

[0038] Preferably, the rotation plane where the connecting movable touch plate 310 is located, the rotation plane where the accelerating movable touch plate 320 is located, and the reciprocating direction of the push rod assembly 200 are parallel to each other, and the connecting movable touch plate 310 and the accelerating movable touch plate 320 are both in contact with the push rod assembly 200. The above arrangement makes the overall working trajectory of the switch simple, the structure compact, and easy to maintain.

[0039] refer to Figure 4 and Figure 5 The push rod assembly 200 includes a telescopic spring 210 and a push rod member 220 connected to the telescopic spring 210 and extending out of the housing. The push rod member 220 is crimped to connect the moving touch plate 310 and the speed-up moving touch plate 320; the telescopic spring 210 pushes the push rod member 220 to a position away from the housing, so that the speed regulating assembly 300 is located in the first position. The setting of the telescopic spring 210 enables the operator to keep the first moving contact 311 away from the first static contact 341, the second moving contact 321 away from the second static contact 351, and the power supply negative plate 330 and the power supply positive plate 350 in a disconnected state when the operator does not push the push rod member 220. The above setting simplifies the operation steps of the operator and improves the work efficiency.

[0040] In this embodiment, the push rod assembly 200 also includes a push rod washer 230 mounted on the push rod member 220 and a push rod button 240 connected to the push rod member 220. A push rod washer groove matching the push rod washer 230 is opened on the shell, and the push rod washer 230 is arranged in the push rod washer groove. The setting of the push rod washer 230 improves the sealing inside the shell and reduces the occurrence of switch damage caused by dust, liquid, etc. in the external environment entering the shell; the setting of the push rod button 240 facilitates the use of the operator.

[0041] Specifically, the push rod member 220 is also provided with a push rod pressure head 222 for crimping the connected moving touch plate 310. A push rod pressure head half hole is opened on the push rod member 220, and a push rod pressure head spring is arranged in the push rod pressure head half hole. One end of the push rod pressure head spring is fixedly connected to the bottom of the push rod pressure head half hole, and the other end is fixedly connected to the push rod pressure head 222, so that the push rod pressure head 222 can reciprocate along the extension direction of the push rod pressure head half hole; the setting of the push rod pressure head 222 makes the specific crimping position of the push rod member 220 and the connected moving touch plate 310 more precise.

[0042] Continue to refer Figure 2 and Figure 3 The connecting moving contact plate 310 is an L-shaped piece, and a third moving contact 312 is provided at one end away from the first moving contact 311; the third moving contact 312 is arranged opposite to the third static contact 331, and the third static contact 331 is arranged on the negative power supply plate 330. When the push rod member 220 of the crimped connecting moving contact plate 310 is located at a position away from the shell, the third moving contact 312 abuts against the third static contact 331, the negative power plate 330 and the positive power plate 350 are in a disconnected state, and the moving contact frame 370, the connecting moving contact plate 310 and the negative power plate 330 are connected in sequence, so that the negative pole of the motor is connected to the positive pole; by arranging the first moving contact 311 and the third moving contact 312 on the L-shaped connecting moving contact plate 310, it can be ensured that the short circuit between the positive pole of the motor and the negative pole of the motor and the working of the power supply will not occur at the same time, and the risk of accidents caused by deformation of the connecting moving touch plate 310 is avoided to a great extent, further improving the safety of the switch.

[0043] refer to Figure 3 and Figure 4, the current regulating member 360 is a field effect transistor, the DC speed regulating switch also includes a circuit board 400, the circuit board 400 is provided with a negative resistor plate 410 and a positive resistor plate 420, and the push rod 220 is installed with an electrical connection piece 221; the two ends of the electrical connection piece 221 can respectively abut against the negative resistor plate 410 and the positive resistor plate 420, so that the negative resistor plate 410 is electrically connected to the positive resistor plate 420; the power supply negative plate 330 is electrically connected to the negative resistor plate 410, and the field effect transistor is electrically connected to the positive resistor plate 420, and an insulating plate 411 is provided at one end of the negative resistor plate 410. When the push rod 220 is located at a position away from the housing, the end of the electrical connection piece 221 close to the negative resistor plate 410 abuts against the insulating plate 411. Specifically, the power supply positive plate 350 is composed of a first power supply positive plate 352 and a second power supply positive plate 353. The positive connection plate 340 is electrically connected to the source of the field effect transistor, and the first power positive plate 352 and the second power positive plate 353 are electrically connected to the gate and drain of the field effect transistor respectively. The arrangement of the circuit board 400 enables the second power supply positive plate 353, the field effect transistor, the first power supply positive plate 352, the positive resistor plate 420, the electrical connecting sheet 221, the negative resistor plate 410 and the power supply negative plate 330 to be electrically connected in sequence, and disconnected when the push rod 220 is located at a position away from the shell; as the push rod 220 moves, the resistance of the parts through which current flows on the negative resistor plate 410 and the positive resistor plate 420 is different, so that the field effect transistor affects the control of the magnitude of the drain current due to the change of the gate current, thereby causing the speed of the motor to change; the arrangement of the circuit board 400 provides installation positions for the negative resistor plate 410 and the positive resistor plate 420, and the selection of the field effect transistor enables the operator to set and adjust the push rod 220 so that the motor can reach a predetermined speed when it moves to any position; the above arrangement facilitates the adjustment of the motor speed and further improves the work efficiency.

[0044] Preferably, the current regulating element 360 is an insulated gate field effect transistor, which has good temperature stability and strong radiation resistance, and has low noise because it does not have shot noise caused by random electron diffusion.

[0045] Continue to refer Figure 2 and Figure 4, two groups of negative electrode resistor plates 410 and positive electrode resistor plates 420 are arranged side by side and connected in series with each other, and two electrical connection plates 221 are arranged side by side; specifically, the power supply negative electrode plate 330 is electrically connected to the first negative electrode resistor plate located above, the upper electrical connection plate is electrically connected to the first negative electrode resistor plate and the first positive electrode resistor plate located above, the first positive electrode resistor plate is electrically connected to the second negative electrode resistor plate located below, the lower electrical connection plate is electrically connected to the second negative electrode resistor plate and the second positive electrode resistor plate located below, and the power supply positive electrode plate 350 is electrically connected to the second positive electrode resistor plate. The above arrangement saves the space occupied by the negative electrode resistor plate 410 and the positive electrode resistor plate 420, and reduces the overall size of the switch.

[0046] At the same time, a carbon film plate 421 is also provided on the positive resistor plate 420; the setting of the carbon film plate 421 changes the resistance at different positions on the positive resistor plate 420, so that when the operator pushes the push rod 220, the resistance value of the part where the current flows through the negative resistor plate 410 and the positive resistor plate 420 changes; by setting the resistance value at different positions on the positive resistor plate 420, the motor can reach a predetermined speed when the push rod 220 moves to any position. The above setting enables the motor to always rotate at the speed predetermined by the operator throughout the entire process of the switch operation; the structure of the switch is improved, and the work efficiency is greatly improved.

[0047] Continue to refer Figure 2 A circuit board cavity 110 and a speed regulating component cavity are provided in the shell, and a shell partition plate for separating the circuit board cavity 110 and the speed regulating component cavity is provided in the middle of the shell. The circuit board 400 is installed in the circuit board cavity 110, and the negative power plate 330, the positive connecting plate 340, the positive power plate 350, the current regulating component 360, the moving contact frame 370, the connecting moving contact plate 310 and the speed-up moving contact plate 320 are all installed in the speed regulating component cavity. The above-mentioned arrangement separates the circuit board 400 from the speed regulating component 300, thereby reducing the influence of factors such as the high temperature of the speed regulating component 300 in the working state and the sparks generated when the moving contact and the static contact abut against each other on the circuit board 400, and effectively improving the service life of the circuit board 400; at the same time, the safety risk of the circuit board 400 is reduced due to the separation arrangement, so that the switch device can reduce the distance between the speed regulating component 300 and the circuit board 400 while ensuring safety, thereby reducing the space occupied by the entire switch; and because a shell partition plate is provided between the speed regulating component 300 and the circuit board 400, the positioning and connection settings of the speed regulating component 300 and the circuit board 400 can be ensured by providing positioning holes and connecting holes on the shell partition plate, so that there is no need to provide positioning holes and connecting holes on the circuit board 400 that match the speed regulating component 300, thereby increasing the available area on the circuit board 400.

[0048] Specifically, the housing is composed of a first side housing 101, a central housing 102, and a second side housing 103 which are spliced ​​in sequence. The first side housing 101 and the central housing 102 are spliced ​​to form a circuit board cavity 110, and the central housing 102 and the second side housing 103 are spliced ​​to form a speed regulating component cavity. The splicing arrangement of the housing facilitates the manufacture and disassembly of the switch, and is convenient for operators to perform debugging and maintenance work. Preferably, the material of the first side housing 101, the central housing 102, and the second side housing 103 is plastic, which is formed by injection molding.

[0049] Furthermore, the DC speed regulating switch further includes a heat sink 500, the speed regulating component cavity includes a current regulating component cavity 121 and a touch plate component cavity 122 opened in the housing, the current regulating component cavity 121 is opened on the housing, and the current regulating component 360 is installed in the current regulating component cavity 121; the heat sink 500 is covered on the current regulating component cavity 121 and is screwed to the housing. The setting of the heat sink 500 facilitates the heat dissipation of the current regulating component 360, so that other structures will not be damaged due to high temperature, and the service life of the switch is extended.

[0050] Preferably, the speed regulating assembly 300 further includes a safety element 380, and the moving contact frame 370 and the negative power supply plate 330 are electrically connected to the two poles of the safety element 380. The provision of the safety element 380 avoids the occurrence of damage to the switch due to unexpected circumstances, thereby improving the safety of the switch operation. Specifically, the safety element 380 is preferably a diode.

[0051] In this embodiment, the DC speed regulation switch also includes a DC power supply, and one end of the power supply negative electrode plate 330 and the power supply positive electrode plate 350 respectively extend out of the shell; one end of the power supply negative electrode plate 330 extending out of the shell is electrically connected to the negative electrode of the DC power supply, and one end of the power supply positive electrode plate 350 extending out of the shell is electrically connected to the positive electrode of the DC power supply.

[0052] According to the above arrangement of this embodiment, when the operator starts to push the push rod button 240, Figure 5As shown, the speed regulating assembly 300 is located in the second position, the push rod pressure head 222 presses the connecting moving contact plate 310 so that the first moving contact 311 abuts against the first static contact 341, and the second power supply positive plate 353, the field effect transistor, the positive connecting plate 340, the connecting moving contact plate 310, the moving contact frame 370, the motor and the power supply negative plate 330 are electrically connected in sequence, the switch circuit is connected, and the current flows through the drain of the field effect transistor, which can drive the motor; at this time, the end of the electrical connecting piece 221 close to the negative resistor plate 410 is separated from the insulating plate 411 and abuts against the negative resistor plate 410, so that the second power supply positive plate 353, the field effect transistor, the first power supply positive plate 352, the positive resistor plate 420, the electrical connecting piece 221, the negative resistor plate 410 and the power supply negative plate 330 are electrically connected in sequence, and the current flows through the gate of the field effect transistor. When the push rod button 240 is pushed further, the electrical connection sheet 221 starts to contact the carbon film plate 421, the magnitude of the gate current changes, and then the magnitude of the drain current changes, so that the motor reaches the corresponding predetermined speed according to the position of the push rod 220; when the resistance value of the part where the current flows through the negative resistor plate 410 and the positive resistor plate 420 decreases, the speed of the motor increases. Figure 6 As shown, the speed regulating assembly 300 is located in the third position, the second moving contact 321 abuts against the second static contact 351, the positive connecting plate 340 and the current regulating member 360 are short-circuited, and the motor runs at full speed. Figure 7 As shown, the speed regulating assembly 300 is located in the first position, and the push rod 220 quickly returns to the initial position under the elastic force of the telescopic spring 210. At this time, the third moving contact 312 abuts against the third static contact 331, and the motor quickly realizes the braking operation under the action of electromagnetic damping.

[0053] This embodiment also provides a DC power tool, including a DC power tool body and a DC speed regulating switch, and the DC speed regulating switch is the DC speed regulating switch mentioned above.

[0054] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A DC speed regulating switch, characterized in that: include: case; A push rod assembly (200) is movably mounted on the housing and can reciprocate along the extension direction of the push rod assembly (200); A speed regulating assembly (300) comprises a motor and a current regulating member (360), wherein the push rod assembly (200) can be pushed to place the speed regulating assembly (300) in different positions; when the speed regulating assembly (300) is in a first position, the positive pole of the power supply is disconnected from the negative pole of the power supply, and the positive pole of the motor is short-circuited from the negative pole of the motor; when the speed regulating assembly (300) is in a second position, the positive pole of the power supply, the current regulating member (360), the motor and the negative pole of the power supply are electrically connected in sequence; when the speed regulating assembly (300) is in a third position, the current regulating member (360) is short-circuited; The speed regulating assembly (300) further comprises a negative power plate (330), a positive connecting plate (340), a positive power plate (350), a connecting moving touch plate (310) and a speed-up moving touch plate (320); the connecting moving touch plate (310) and the speed-up moving touch plate (320) are respectively rotatably connected to a moving contact frame (370); the moving contact frame (370) and the negative power plate (330) are respectively electrically connected to two poles of the motor; one end of the connecting moving touch plate (310) is provided with a first moving contact (311); the speed-up moving contact A second moving contact (321) is provided at one end of the plate (320); a first static contact (341) is provided on the positive connecting plate (340), and a second static contact (351) is provided on the positive power plate (350); the first moving contact (311) is arranged opposite to the first static contact (341), and the second moving contact (321) is arranged opposite to the second static contact (351); the current regulating member (360) is electrically connected to the positive connecting plate (340) and the positive power plate (350), respectively.

2. The DC speed regulating switch according to claim 1, characterized in that: The rotation plane where the connecting movable touch plate (310) is located, the rotation plane where the accelerating movable touch plate (320) is located, and the reciprocating direction of the push rod assembly (200) are parallel to each other, and the connecting movable touch plate (310) and the accelerating movable touch plate (320) are both in contact with the push rod assembly (200).

3. The DC speed regulating switch according to claim 2, characterized in that: The push rod assembly (200) comprises a telescopic spring (210) and a push rod member (220) connected to the telescopic spring (210) and extending out of the housing, wherein the push rod member (220) is pressed against the connecting movable touch plate (310) and the speed-up movable touch plate (320); the telescopic spring (210) pushes the push rod member (220) to a position away from the housing, so that the speed regulating assembly (300) is located at the first position.

4. The DC speed regulating switch according to claim 3, characterized in that: The connecting movable contact plate (310) is an L-shaped piece, and a third movable contact (312) is arranged at one end away from the first movable contact (311); the third movable contact (312) is arranged opposite to the third static contact (331), and the third static contact (331) is arranged on the negative plate (330) of the power supply.

5. The DC speed regulating switch according to claim 3, characterized in that: The current regulating member (360) is a field effect transistor, the DC speed regulating switch further comprises a circuit board (400), the circuit board (400) is provided with a negative electrode resistor plate (410) and a positive electrode resistor plate (420), and the push rod member (220) is provided with an electrical connection sheet (221); two ends of the electrical connection sheet (221) can respectively abut against the negative electrode resistor plate (410) and the positive electrode resistor plate (420), so that the negative electrode resistor plate (410) and the positive electrode resistor plate (420) are connected to each other. The positive resistor plate (420) is electrically connected; the negative power supply plate (330) is electrically connected to the negative resistor plate (410); the field effect transistor is electrically connected to the positive resistor plate (420); an insulating plate (411) is provided at one end of the negative resistor plate (410); when the push rod (220) is located at a position away from the shell, one end of the electrical connection sheet (221) close to the negative resistor plate (410) abuts against the insulating plate (411).

6. The DC speed regulating switch according to claim 5, characterized in that: A circuit board cavity (110) and a speed regulating component cavity are provided in the shell, and a shell partition plate for separating the circuit board cavity (110) and the speed regulating component cavity is provided in the middle of the shell. The circuit board (400) is installed in the circuit board cavity (110), and the negative power plate (330), the positive connecting plate (340), the positive power plate (350), the current regulating component (360), the moving contact frame (370), the connecting moving contact plate (310) and the speed-up moving contact plate (320) are all installed in the speed regulating component cavity.

7. The DC speed regulating switch according to claim 6, characterized in that: The DC speed regulating switch further comprises a heat sink (500); the speed regulating component cavity comprises a current regulating component cavity (121) and a touch plate component cavity (122) opened in the shell; the current regulating component cavity (121) is opened on the shell; the current regulating component (360) is installed in the current regulating component cavity (121); the heat sink (500) is covered on the current regulating component cavity (121) and is screwed to the shell.

8. The DC speed regulating switch according to claim 1, characterized in that: The speed regulating component (300) further comprises a safety component (380), and the moving contact frame (370) and the negative power supply plate (330) are respectively electrically connected to two poles of the safety component (380).

9. A DC power tool, comprising a DC power tool body and a DC speed regulating switch, characterized in that: The DC speed regulating switch is a DC speed regulating switch according to any one of claims 1 to 8.

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