CN114695004A - Direct current speed regulation switch and direct current electric tool - Google Patents

Abstract

The invention relates to the technical field of speed regulating switches, and particularly discloses a direct-current speed regulating switch and a direct-current electric tool. The switch comprises a shell, a push rod component and a speed regulating component; the push rod component is movably arranged on the shell and can reciprocate along the extension direction of the push rod component; the speed regulating assembly is arranged in the shell and comprises a motor and a current regulating member, wherein the speed regulating assembly can be positioned at different positions by pushing the push rod assembly, when the push rod assembly is positioned at a first position, the positive pole of the power supply and the negative pole of the power supply are in open circuit, and the positive pole of the motor and the negative pole of the motor are in short circuit; when the motor is positioned at the second position, the positive electrode of the power supply, the current regulating piece, the motor and the negative electrode of the power supply are electrically connected in sequence; in the third position, the current regulator is shorted. The switch can finish the speed regulation operation of the motor by pushing the push rod assembly, thereby facilitating the regulation of the rotating speed of the motor by operators and improving the working efficiency; the risk of faults caused by abnormal connection state is avoided, and the safety of the switch in use is ensured.

Description

Direct current speed regulation switch and direct current electric tool

Technical Field

The invention relates to the technical field of speed regulating switches, in particular to a direct-current speed regulating switch and a direct-current electric tool.

Background

The direct current speed regulating switch is widely applied to the field of direct current electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers and the like, and mainly comprises a contact mechanism and a push rod mechanism for controlling the on-off of the contact mechanism.

In the prior art, in order to facilitate the adjustment of the working speed of the electric tool using the dc speed regulation switch, the dc speed regulation switch is operated to adjust the rotating speed of the motor. The brake operation and the speed regulation operation of the existing direct current speed regulation switch are respectively realized by two different components, when the position of the component is deviated due to the deformation or bonding of the component and other problems of the switch, the connection state of a circuit is abnormal, the short circuit between the anode of a motor and the cathode of the motor is easily caused under the working state of a power supply, the faults such as the switch is burnt out by large current and the like are caused, and the potential safety hazard is formed for a direct current power tool.

Disclosure of Invention

The invention aims to provide a direct-current speed regulation switch and a direct-current electric tool, which are convenient for an operator to regulate the rotating speed of a motor under the condition of avoiding an abnormal connection state.

In order to achieve the purpose, the invention adopts the following technical scheme:

a DC speed regulation switch comprises a shell, a push rod component and a speed regulation component; the push rod assembly is movably arranged on the shell and can reciprocate along the extension direction of the push rod assembly; the speed regulation assembly comprises a motor and a current regulation piece, wherein the speed regulation assembly can be positioned at different positions by pushing the push rod assembly, when the push rod assembly is positioned at a first position, the positive pole of a power supply and the negative pole of the power supply are in open circuit, and the positive pole of the motor and the negative pole of the motor are in short circuit; when the motor is located at the second position, the positive electrode of the power supply, the current regulating piece, the motor and the negative electrode of the power supply are electrically connected in sequence; in the third position, the current regulator is shorted.

The speed regulation assembly further comprises a power supply negative plate, a positive connecting plate, a power supply positive plate, a connecting movable contact plate and a speed-up movable contact plate, wherein the connecting movable contact plate and the speed-up movable contact plate are respectively in rotating connection with a movable contact frame, and the movable contact frame and the power supply negative plate are respectively and electrically connected with two poles of the motor; one end of the speed-up movable contact plate is provided with a second movable contact; the positive connecting plate is provided with a first fixed contact, the positive plate of the power supply is provided with a second fixed contact, the first moving contact and the first fixed contact are arranged just opposite to each other, the second moving contact and the second fixed contact are arranged just opposite to each other, and the current adjusting part is respectively electrically connected with the positive connecting plate and the positive plate of the power supply.

Furthermore, the rotating plane where the connecting movable contact plate is located, the rotating plane where the speed-up movable contact plate is located and the reciprocating direction of the push rod assembly are parallel to each other, and the connecting movable contact plate and the speed-up movable contact plate are both abutted to the push rod assembly.

Still further, the push rod assembly comprises a telescopic spring and a push rod piece which is connected with the telescopic spring and extends out of the shell, and the push rod piece is in compression joint with the connecting movable contact plate and the speed-up movable contact plate; the telescopic spring pushes the push rod piece to a position far away from the shell, so that the speed regulating assembly is located at the first position.

Furthermore, the connecting movable contact plate is an L-shaped part, and one end of the connecting movable contact plate, which is far away from the first movable contact, is provided with a third movable contact; the third moving contact and the third fixed contact are arranged just opposite to each other, and the third fixed contact is arranged on the power supply negative plate.

Preferably, the current adjusting part is a field effect transistor, the direct current speed regulation switch further comprises a circuit board, a negative resistance plate and a positive resistance plate are arranged on the circuit board, and an electric connection sheet is mounted on the push rod part; two ends of the electric connecting sheet can be respectively abutted against the negative resistance plate and the positive resistance plate, so that the negative resistance plate is electrically connected with the positive resistance plate; the power negative plate electricity is connected the negative resistance board, field effect transistor electricity is connected the positive resistance board, negative resistance board one end is provided with the insulation board, is located when the push rod piece is located keep away from when the position of casing, the electricity connection piece is close to the one end butt of negative resistance board in on the insulation board.

Furthermore, a circuit board cavity and a speed regulation part cavity are formed in the shell, a shell separation plate used for separating the circuit board cavity from the speed regulation part cavity is arranged in the middle of the shell, the circuit board is installed in the circuit board cavity, and the power negative plate, the positive connecting plate, the power positive plate, the current regulation part, the movable contact frame, the connecting movable contact plate and the speed-increasing movable contact plate are all installed in the speed regulation part cavity.

Still further, the direct current speed regulation switch also comprises a heat dissipation plate, the speed regulation part cavity comprises a current regulation part cavity and a touch plate part cavity arranged in the shell, the current regulation part cavity is arranged on the shell, and the current regulation part is arranged in the current regulation part cavity; the radiating plate cover is arranged on the current regulating part cavity and is in threaded connection with the shell.

Preferably, the speed regulation assembly further comprises a safety piece, and the movable contact frame and the power negative plate are respectively and electrically connected with two poles of the safety piece.

A direct current electric tool comprises a direct current electric tool main body and a direct current speed regulating switch, wherein the direct current speed regulating switch is the direct current speed regulating switch.

The invention has the beneficial effects that:

by means of the arrangement of the speed regulating assembly, the switch is configured to be different in electric connection state when the push rod assembly moves to different positions; by means of the current regulating element, the regulation of the motor speed can be realized through the change of the current. When the positive pole and the negative pole of the power supply are in open circuit, the positive pole and the negative pole of the motor are in short circuit, so that the situation that the positive pole and the negative pole of the motor are in short circuit in the working state of the power supply is avoided, and the safety of the switch work is ensured; when the current adjusting part is short-circuited, the current passing through the motor is increased, so that the rotating speed of the motor is further increased, and the setting is utilized to ensure that an operator can complete the adjustment of the rotating speed of the motor by controlling the position of the push rod assembly.

Drawings

Fig. 1 is a schematic circuit diagram of a dc speed-regulating switch according to an embodiment of the present invention;

fig. 2 is an exploded view of a dc speed-regulating switch provided in an embodiment of the present invention;

FIG. 3 is an exploded view of a governor assembly provided by an embodiment of the present invention;

FIG. 4 is a schematic structural view of a putter assembly according to an embodiment of the present invention;

FIG. 5 is a schematic structural view of a second position of the governor assembly provided by the embodiment of the present invention;

FIG. 6 is a schematic structural view of a third position of the governor assembly provided by the embodiment of the present invention;

FIG. 7 is a schematic diagram of a first position of the governor assembly according to an embodiment of the present invention.

In the figure:

101. a first side case; 102. a center housing; 103. a second side case; 110. a circuit board cavity; 121. a current regulator cavity; 122. a contact plate member cavity;

200. a push rod assembly; 210. a tension spring; 220. a pusher member; 221. an electrically connecting sheet; 222. a push rod pressure head; 230. a push rod washer; 240. a push-rod button;

300. a speed regulation component; 310. connecting a movable touch plate; 311. a first moving contact; 312. a third moving contact; 320. a speed-up movable touch panel; 321. a second moving contact; 322. accelerating the moving contact plate spring; 330. a negative plate of a power supply; 331. a third static contact; 340. a positive electrode connecting plate; 341. a first fixed contact; 350. a positive plate of a power supply; 351. a second fixed contact; 352. a first positive power supply plate; 353. a second positive power supply plate; 360. a current regulating member; 370. a movable contact frame; 380. a safety element; 390. a plate frame;

400. a circuit board; 410. a negative resistance plate; 411. an insulating plate; 420. a positive resistance plate; 421. a carbon film plate; 500. a heat sink.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

As shown in fig. 1 and 2, the present embodiment provides a dc speed regulation switch, which includes a housing, a push rod assembly 200 and a speed regulation assembly 300; the push rod assembly 200 is movably mounted on the housing and can reciprocate along the extending direction of the push rod assembly 200; the speed regulation assembly 300 comprises a motor and a current regulation piece 360, wherein the push rod assembly 200 is pushed to enable the speed regulation assembly 300 to be located at different positions, when the push rod assembly is located at a first position, the positive pole of a power supply and the negative pole of the power supply are in open circuit, and the positive pole of the motor and the negative pole of the motor are in short circuit; when the motor is positioned at the second position, the positive electrode of the power supply, the current adjusting piece 360, the motor and the negative electrode of the power supply are electrically connected in sequence; in the third position, the current regulator 360 is shorted. By virtue of the arrangement of the speed regulation assembly 300, the switches are configured to have different electrical connection states when the push rod assembly 200 moves to different positions; by means of the current regulator 360, the motor speed can be regulated by changing the current. When the positive pole and the negative pole of the power supply are in open circuit, the positive pole and the negative pole of the motor are in short circuit, so that the situation that the positive pole and the negative pole of the motor are in short circuit in the working state of the power supply is avoided, and the safety of the switch work is ensured; when the current adjusting part 360 is short-circuited, the current passing through the motor is increased, so that the rotating speed of the motor is further increased, and the setting is utilized to ensure that an operator can complete the adjustment of the rotating speed of the motor by controlling the position of the push rod assembly 200.

As shown in fig. 2 and 3, the speed regulation assembly 300 further includes a negative power plate 330, a positive connection plate 340, a positive power plate 350, a connection movable contact plate 310 and a speed-up movable contact plate 320, the connection movable contact plate 310 and the speed-up movable contact plate 320 are respectively rotatably connected with a movable contact frame 370, and the movable contact frame 370 and the negative power plate 330 are respectively electrically connected with two poles of the motor; one end of the connection movable contact plate 310 is provided with a first movable contact 311, and one end of the speed-up movable contact plate 320 is provided with a second movable contact 321; the positive connecting plate 340 is provided with a first fixed contact 341, the positive power plate 350 is provided with a second fixed contact 351, the first movable contact 311 is arranged opposite to the first fixed contact 341, the second movable contact 321 is arranged opposite to the second fixed contact 351, and the current adjusting part 360 is electrically connected with the positive connecting plate 340 and the positive power plate 350 respectively. With the above arrangement, when the speed regulation assembly 300 is located at the second position, the first moving contact 311 abuts against the first fixed contact 341, and the second moving contact 321 is away from the second fixed contact 351, at this time, the positive power plate 350, the current adjusting member 360, the positive connecting plate 340, the connecting moving contact plate 310, the moving contact frame 370, the motor and the negative power plate 330 are electrically connected in sequence; when the speed regulation assembly 300 is located at the third position, the first moving contact 311 abuts against the first fixed contact 341, the second moving contact 321 abuts against the second fixed contact 351, the speed-up moving contact plate 320 electrically connected with the moving contact frame 370 is directly and electrically connected with the positive power plate 350, and the positive connection plate 340 and the current regulation member 360 are short-circuited due to the arrangement. According to the arrangement, the current passing by the motor can be different by pushing the push rod assembly 200, and further the adjustment of the rotating speed of the motor is realized. The device is simple in structure, low in cost and convenient to maintain.

With continued reference to fig. 1, when the speed adjustment assembly 300 is in the first position, the connection movable contact plate 310 and the speed-increasing movable contact plate 320 are both disconnected, while the connection movable contact plate 310 short-circuits the motor; in the second position, the connecting moving contact plate 310 is engaged and the speed-up moving contact plate 320 is disengaged; in the third position, the speed-up moving contact plate 320 is engaged.

With continued reference to fig. 2 and 3, the negative power plate 330, the positive connecting plate 340, the positive power plate 350 and the moving contact frame 370 are all mounted on the frame 390, the speed-up moving contact plate 320 is an L-shaped member, and the second moving contact 321 is disposed at one end of the vertical plate of the speed-up moving contact plate 320; the plate frame 390 is further provided with a speed-up moving contact plate spring 322, one end of the speed-up moving contact plate spring 322 is connected to the plate frame 390, the other end of the speed-up moving contact plate spring 322 is clamped on a vertical plate of the speed-up moving contact plate 320, and the speed-up moving contact plate spring 322 pulls the speed-up moving contact plate 320 to rotate towards the position where the power positive plate 350 is arranged; when the speed regulating assembly 300 is not located at the third position, the push rod member 220 is pressed against the transverse plate of the speed regulating moving contact plate 320, and the second moving contact 321 is far away from the second fixed contact 351; when the speed adjusting assembly 300 is located at the third position, the push rod 220 no longer presses against the transverse plate of the speed-increasing moving contact plate 320, and the speed-increasing moving contact plate spring 322 pulls the speed-increasing moving contact plate 320 to rotate, so that the second moving contact 321 abuts against the second fixed contact 351. The arrangement of the rack 390 makes the structure of the switch more compact; meanwhile, the speed regulating assembly 300 is modularized, and the installation and operation of the speed regulating assembly 300 are facilitated.

Preferably, the rotation plane on which the connection movable contact plate 310 is located, the rotation plane on which the speed-increasing movable contact plate 320 is located, and the direction of the reciprocating movement of the push rod assembly 200 are parallel to each other, and both the connection movable contact plate 310 and the speed-increasing movable contact plate 320 abut against the push rod assembly 200. The arrangement ensures that the overall working track of the switch is simple, the structure is compact and the maintenance is convenient.

As shown in fig. 4, 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 being press-connected to the moving contact plate 310 and the speed-up moving contact plate 320; the extension spring 210 pushes the push rod member 220 to a position away from the housing, so that the governor assembly 300 is located at the first position. The arrangement of the extension spring 210 enables the first movable contact 311 to be far away from the first fixed contact 341, the second movable contact 321 to be far away from the second fixed contact 351, and the negative power plate 330 and the positive power plate 350 are in an off state when an operator does not push the push rod 220. The arrangement simplifies the operation steps of operators and improves the working efficiency.

In this embodiment, the push rod assembly 200 further includes a push rod gasket 230 sleeved on the push rod 220 and a push rod button 240 connected to the push rod 220, the housing is provided with a push rod gasket groove matched with the push rod gasket 230, the push rod gasket 230 is arranged in the push rod gasket groove, the arrangement of the push rod gasket 230 improves the sealing property in the housing, and reduces the occurrence of switch damage and the like caused by dust, liquid and the like in the external environment entering the housing; the push button 240 is provided for convenient use by the operator.

Specifically, the push rod piece 220 is further provided with a push rod pressure head 222 for being in compression joint with the movable contact plate 310, the push rod piece 220 is provided with a push rod pressure head half hole, 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 of the push rod pressure head spring 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 push rod ram 222 is positioned to provide more precise location of the particular crimp of the push rod member 220 to the connecting movable contact plate 310.

With continued reference to fig. 2 and fig. 3, the connecting moving contact plate 310 is an L-shaped member, and one end away from the first moving contact 311 is provided with a third moving contact 312; the third moving contact 312 is opposite to the third fixed contact 331, and the third fixed contact 331 is disposed on the negative power plate 330. When the push rod member 220 connected with the movable contact plate 310 in a crimping manner is located at a position far away from the shell, the third movable contact 312 abuts against the third fixed contact 331, the power negative plate 330 and the power positive plate 350 are in a disconnected state, and the movable contact frame 370, the movable contact plate 310 and the power negative plate 330 are connected in sequence, so that the negative electrode of the motor is connected with the positive electrode; by arranging the first moving contact 311 and the third moving contact 312 on the L-shaped connecting moving contact plate 310, the short circuit between the positive pole and the negative pole of the motor and the working condition of the power supply can be ensured not to occur simultaneously, and the risk of accidents caused by the deformation of the connecting moving contact plate 310 is avoided to a great extent; the safety of the switch is further improved.

Referring to fig. 3 and 4, the current adjusting member 360 is a field effect transistor, the dc speed-regulating switch further includes a circuit board 400, a negative resistance plate 410 and a positive resistance plate 420 are disposed on the circuit board 400, and the push rod member 220 is mounted with an electrical connection sheet 221; two ends of the electric connection sheet 221 can respectively abut against the negative resistance plate 410 and the positive resistance plate 420, so that the negative resistance plate 410 is electrically connected with the positive resistance plate 420; the negative electrode plate 330 of the power supply is electrically connected with the negative resistance plate 410, the field effect transistor is electrically connected with the positive resistance plate 420, one end of the negative resistance plate 410 is provided with an insulating plate 411, and when the push rod piece 220 is located at a position far away from the shell, one end of the electric connecting piece 221 close to the negative resistance plate 410 is abutted to the insulating plate 411. Specifically, the power positive plate 350 is composed of a first power positive plate 352 and a second power positive plate 353. The positive electrode connection plate 340 is electrically connected to a source electrode of the field effect transistor, and the first power positive electrode plate 352 and the second power positive electrode plate 353 are electrically connected to a gate electrode and a drain electrode of the field effect transistor, respectively. The circuit board 400 is arranged so that the second positive power supply plate 353, the field effect transistor, the first positive power supply plate 352, the positive resistance plate 420, the electrical connection sheet 221, the negative resistance plate 410 and the negative power supply plate 330 are electrically connected in sequence and disconnected when the push rod member 220 is located at a position away from the case; with the movement of the push rod member 220, the resistances of the current flowing parts on the negative resistance plate 410 and the positive resistance plate 420 are different, so that the field effect transistor influences the control of the magnitude of the current flowing through the drain due to the change of the current flowing through the gate, and further the rotating speed of the motor is changed; the arrangement of the circuit board 400 is such that the negative resistance plate 410 and the positive resistance plate 420 provide mounting positions, and the selection of the field effect transistor enables an operator to enable the motor to reach a preset rotating speed when the push rod member 220 moves to any position through arrangement and adjustment; the arrangement facilitates the adjustment of the rotating speed of the motor, and the working efficiency is further improved.

Preferably, the current regulator 360 is an insulated gate field effect transistor. The insulated gate field effect transistor has good temperature stability and strong radiation resistance, and has low noise because the scattered noise caused by disordered moving electron diffusion does not exist.

With continued reference to fig. 2 and 4, the negative resistance plates 410 and the positive resistance plates 420 are provided in two sets, arranged side by side and in series with each other, and the electrical connection tabs 221 are provided in two sets side by side; specifically, the negative power plate 330 is electrically connected to the first negative resistance plate located above, the upper connecting tab is electrically connected to the first negative resistance plate and the first positive resistance plate located above, the first positive resistance plate is electrically connected to the second negative resistance plate located below, the lower connecting tab is electrically connected to the second negative resistance plate and the second positive resistance plate located below, and the positive power plate 350 is electrically connected to the second positive resistance plate. The arrangement saves the space occupied by the negative resistance plate 410 and the positive resistance plate 420, and reduces the size of the whole switch.

Meanwhile, the positive resistance plate 420 is also provided with a carbon film plate 421; the arrangement of the carbon film plate 421 changes the resistance at different positions on the positive resistance plate 420, so that the resistance of the current flowing through the negative resistance plate 410 and the positive resistance plate 420 is changed when the push rod member 220 is pushed by an operator; by setting the sizes of the resistors at different positions on the positive resistance plate 420, the motor can reach a predetermined rotation speed when the push rod member 220 moves to any position. The arrangement enables the motor to rotate at a rotating speed preset by an operator all the time in the whole working process of the switch; the structure of the switch is improved, and the working efficiency is greatly improved.

With reference to fig. 2, a circuit board cavity 110 and a speed regulating cavity are formed in the casing, a casing partition plate for partitioning the circuit board cavity 110 and the speed regulating cavity is arranged in the middle of the casing, 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 part 360, the movable contact frame 370, the connecting movable contact plate 310 and the speed-increasing movable contact plate 320 are all installed in the speed regulating cavity. The arrangement enables the circuit board 400 and the speed regulation assembly 300 to be arranged separately, reduces the influence of factors such as high temperature of the circuit board 400 in the working state of the speed regulation assembly 300, sparks generated when the moving contact is abutted to the static contact and the like, and effectively prolongs the service life of the circuit board 400; meanwhile, the safety risk of the circuit board 400 is reduced due to the separation arrangement, so that the distance between the speed regulating component 300 and the circuit board 400 can be reduced by the switch device on the premise of ensuring the safety, and the space occupied by the whole switch is further reduced; and because the shell separation plate is arranged between the speed regulation assembly 300 and the circuit board 400, the positioning and connection arrangement of the speed regulation assembly 300 and the circuit board 400 can be ensured by arranging the positioning hole and the connecting hole on the shell separation plate, so that the positioning hole and the connecting hole matched with the speed regulation assembly 300 are not required to be arranged on the circuit board 400, and the available area on the circuit board 400 is increased.

Specifically, the housing is composed of a first side shell 101, a central shell 102 and a second side shell 103 which are sequentially spliced, the first side shell 101 and the central shell 102 are spliced to form a circuit board cavity 110, and the central shell 102 and the second side shell 103 are spliced to form a speed regulating member cavity. The splicing arrangement of the shell facilitates the manufacture, the disassembly and the assembly of the switch, and is convenient for operators to debug and maintain. Preferably, the materials of the first side shell 101, the center shell 102 and the second side shell 103 are plastics and are formed by injection molding.

Further, the direct current speed regulation switch further comprises a heat dissipation plate 500, the speed regulation part cavity comprises a current regulation part cavity 121 and a touch plate part cavity 122 arranged in the shell, the current regulation part cavity 121 is arranged on the shell, and the current regulation part 360 is arranged in the current regulation part cavity 121; the heat sink 500 covers the current regulator cavity 121 and is screwed to the housing. The heat dissipation plate 500 facilitates heat dissipation of the current adjusting member 360, so that other structures are not damaged due to high temperature, and the service life of the switch is prolonged.

Preferably, the speed regulation assembly 300 further includes a fuse 380, and the movable contact frame 370 and the power negative plate 330 are electrically connected to two poles of the fuse 380, respectively. The fuse 380 prevents the switch from being damaged due to an accident, and improves the safety of the switch operation. Specifically, fuse 380 is preferably a diode.

In this embodiment, the dc speed-adjusting switch further includes a dc power supply, and one end of the negative power supply plate 330 and one end of the positive power supply plate 350 respectively extend out of the housing; one end of the negative power plate 330 extending out of the shell is electrically connected with the negative electrode of the direct current power supply, and one end of the positive power plate 350 extending out of the shell is electrically connected with the positive electrode of the direct current power supply.

According to the above arrangement of the embodiment, when the operator starts to push the push button 240, as shown in fig. 5, the speed adjusting assembly 300 is located at the second position, the push ram head 222 is connected to the movable contact plate 310 in a press-fit manner, so that the first movable contact 311 abuts against the first fixed contact 341, the second positive power plate 353, the field effect transistor, the positive connection plate 340, the connection movable contact plate 310, the movable contact frame 370, the motor and the negative power plate 330 are electrically connected in sequence, the switch circuit is connected, and the current flows through the drain of the field effect transistor, so as to drive the motor; at this time, one end of the electrical connection sheet 221, which is close to the negative resistance plate 410, is separated from the insulating plate 411 and abuts against the negative resistance plate 410, so that the second positive power supply plate 353, the field effect transistor, the first positive power supply plate 352, the positive resistance plate 420, the electrical connection sheet 221, the negative resistance plate 410, and the negative power supply plate 330 are electrically connected in sequence, and current flows through the gate of the field effect transistor. When the push rod button 240 is pushed continuously, the electric connecting sheet 221 starts to contact the carbon film plate 421, and the magnitude of the current passing through the grid electrode changes, so that the magnitude of the current passing through the drain electrode is changed, and the motor reaches the corresponding preset rotating speed according to the moving position of the push rod member 220; when the resistance value of the portion of the negative resistance plate 410 and the positive resistance plate 420 through which the current flows decreases, the rotation speed of the motor increases. When the push-rod button 240 is pushed again, as shown in fig. 6, the speed-regulating assembly 300 is located at the third position, the second moving contact 321 abuts against the second stationary contact 351, and the positive connection board 340 and the current regulator 360 are short-circuited, so that the motor operates at full speed. When the push rod button 240 is released, as shown in fig. 7, the speed adjusting assembly 300 is located at the first position, the push rod member 220 rapidly returns to the initial position under the action of the elastic force of the extension spring 210, at this time, the third moving contact 312 abuts against the third stationary contact 331, and the motor rapidly realizes the braking operation under the action of the electromagnetic damping.

The embodiment further provides a direct current electric tool, which comprises a direct current electric tool main body and a direct current speed regulating switch, wherein the direct current speed regulating switch is the direct current speed regulating switch.

It should be understood that the above-described 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. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (10)

1. A DC speed-regulating switch, comprising:

a housing;

the push rod assembly (200) is movably arranged on the shell and can reciprocate along the extending direction of the push rod assembly (200);

the speed regulation assembly (300) comprises a motor and a current regulation piece (360), wherein the push rod assembly (200) is pushed to enable the speed regulation assembly (300) to be located at different positions, when the push rod assembly is located at a first position, the positive pole of a power supply and the negative pole of the power supply are in open circuit, and the positive pole of the motor and the negative pole of the motor are in short circuit; when the motor is located at the second position, the positive electrode of the power supply, the current regulating piece (360), the motor and the negative electrode of the power supply are electrically connected in sequence; in the third position, the current regulator (360) is short circuited.

2. The direct-current speed regulation switch of claim 1, wherein the speed regulation assembly (300) further comprises a negative power supply plate (330), a positive connecting plate (340), a positive power supply plate (350), a connecting movable contact plate (310) and a speed-increasing movable contact plate (320), the connecting movable contact plate (310) and the speed-increasing movable contact plate (320) are respectively in rotating connection with a movable contact frame (370), and the movable contact frame (370) and the negative power supply plate (330) are respectively and electrically connected with two poles of the motor; one end of the connecting movable contact board (310) is provided with a first movable contact (311), and one end of the speed-increasing movable contact board (320) is provided with a second movable contact (321); the positive electrode connecting plate (340) is provided with a first fixed contact (341), the power positive plate (350) is provided with a second fixed contact (351), the first movable contact (311) is arranged opposite to the first fixed contact (341), the second movable contact (321) is arranged opposite to the second fixed contact (351), and the current adjusting piece (360) is electrically connected with the positive electrode connecting plate (340) and the power positive plate (350) respectively.

3. The dc speed-regulating switch according to claim 2, wherein the rotation plane of the connecting movable contact plate (310), the rotation plane of the speed-increasing movable contact plate (320) and the reciprocating direction of the push rod assembly (200) are parallel to each other, and both the connecting movable contact plate (310) and the speed-increasing movable contact plate (320) are abutted against the push rod assembly (200).

4. The dc speed regulating switch according to claim 3, wherein the push rod assembly (200) comprises a telescopic spring (210) and a push rod member (220) connected with the telescopic spring (210) and extending out of the housing, the push rod member (220) is pressed against the connecting movable contact plate (310) and the speed-increasing movable contact plate (320); the telescopic spring (210) pushes the push rod piece (220) to a position far away from the shell, so that the speed regulating assembly (300) is located at the first position.

5. The dc speed regulation switch of claim 4, wherein the connecting moving contact plate (310) is an L-shaped member, and a third moving contact (312) is disposed at an end away from the first moving contact (311); the third moving contact (312) is arranged opposite to the third fixed contact (331), and the third fixed contact (331) is arranged on the power supply negative plate (330).

6. The direct current speed regulation switch of claim 4, wherein the current regulation member (360) is a field effect transistor, the direct current speed regulation switch further comprises a circuit board (400), a negative resistance plate (410) and a positive resistance plate (420) are arranged on the circuit board (400), and an electric connection sheet (221) is mounted on the push rod member (220); two ends of the electric connection sheet (221) can be respectively abutted against the negative resistance plate (410) and the positive resistance plate (420) to electrically connect the negative resistance plate (410) and the positive resistance plate (420); the power negative plate (330) electricity is connected negative resistance board (410), field effect transistor electricity is connected positive resistance board (420), negative resistance board (410) one end is provided with insulating board (411), when push rod spare (220) are located keep away from when the position of casing, electric connection piece (221) are close to the one end butt of negative resistance board (410) in on insulating board (411).

7. The direct-current speed regulation switch according to claim 6, wherein a circuit board cavity (110) and a speed regulation part cavity are formed in the shell, a shell separation plate for separating the circuit board cavity (110) from the speed regulation part cavity is arranged in the middle of the shell, the circuit board (400) is installed in the circuit board cavity (110), and the power negative plate (330), the positive connecting plate (340), the power positive plate (350), the current regulation part (360), the movable contact frame (370), the connecting movable contact plate (310) and the speed-increasing movable contact plate (320) are all installed in the speed regulation part cavity.

8. The dc speed regulating switch according to claim 7, further comprising a heat dissipating plate (500), wherein the speed regulating member cavity comprises a current regulating member cavity (121) and a touch plate member cavity (122) provided in the housing, the current regulating member cavity (121) is provided in the housing, and the current regulating member (360) is installed in the current regulating member cavity (121); the heat dissipation plate (500) is covered on the current regulating part cavity (121) and is in threaded connection with the shell.

9. The dc speed regulation switch of claim 2, wherein the speed regulation assembly (300) further comprises a safety member (380), and the movable contact holder (370) and the negative power supply plate (330) are electrically connected to two poles of the safety member (380), respectively.

10. A dc power tool comprising a dc power tool body and a dc speed switch, wherein the dc speed switch is according to any one of claims 1 to 9.

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