CN213958847U

CN213958847U - Direct current speed regulation switch and direct current electric tool

Info

Publication number: CN213958847U
Application number: CN202023237864.5U
Authority: CN
Inventors: 梁勇; 郭锐
Original assignee: Shanghai Baicheng Electric Equipment Manufacture Co Ltd
Current assignee: Shanghai Baicheng Electric Equipment Manufacture Co Ltd
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2021-08-13
Anticipated expiration: 2030-12-29

Abstract

The utility model relates to a speed governing switch technical field specifically discloses a direct current speed governing switch and direct current electric tool. The switch comprises a shell, a circuit board and a speed regulating component; the speed regulating assembly comprises a motor, a moving contact and a static contact, and when the moving contact is abutted against/separated from the static contact, the position of the speed regulating assembly is changed, so that the rotating speed of the motor is changed; the circuit board cavity and the speed regulating part cavity are formed in the shell, the shell partition plate used for separating the circuit board cavity and the speed regulating part cavity is arranged in the middle of the shell, the circuit board is installed in the circuit board cavity, and the moving contact and the static contact are installed in the speed regulating part cavity. The shell partition plate separates the circuit board and the speed regulation assembly, so that the influence of factors such as high temperature of the circuit board in the working state of the speed regulation assembly, sparks generated when the moving contact is abutted to the static contact and the like is reduced, and the service life of the circuit board is prolonged; meanwhile, the safety risk of the circuit board is reduced, the distance between the speed regulation component and the circuit board is reduced on the premise of ensuring the safety, and the space occupied by the switch can be reduced.

Description

Direct current speed regulation switch and direct current electric tool

Technical Field

The utility model relates to a speed governing switch technical field especially relates to a direct current speed governing switch and 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.

The direct current speed regulation switch comprises a speed regulation component and a circuit board, high temperature can be generated in the working process of the speed regulation component, and electric sparks can be generated when the moving contact is abutted to the static contact. In the prior art, in order to prevent the damage of the components on the circuit board caused by heat or splashed sparks, the circuit board is often arranged far away from the speed regulating assembly so as to prevent the circuit board from being damaged. The direct-current speed regulation switch has the advantages that the occupied space is too large, the service life is short, the safety of the switch cannot be guaranteed, and the actual requirements of the current engineering on the switch cannot be met.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a direct current speed governing switch and direct current electric tool to make things convenient for operating personnel can use push rod assembly to accomplish the regulation to motor speed in operation process.

To achieve the purpose, the utility model adopts the following technical proposal:

a DC speed regulation switch comprises a shell, a push rod component and a circuit board; the speed regulating assembly comprises a motor, a moving contact and a fixed contact, and when the moving contact abuts against/leaves the fixed contact, the position of the speed regulating assembly is changed, so that the rotating speed of the motor is changed; the circuit board is arranged in the shell; the circuit board is mounted in the circuit board cavity, and the moving contact and the static contact are mounted in the speed regulating part cavity.

Preferably, the speed regulation assembly further comprises a current regulation piece, wherein when the speed regulation assembly is located at the first position, the positive pole of the power supply is disconnected with 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 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.

Furthermore, 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 housing is composed of a first side shell, a central shell and a second side shell which are spliced in sequence, the first side shell and the central shell are spliced to form the circuit board cavity, and the central shell and the second side shell are spliced to form the speed regulating member cavity.

Further, the materials of the first side shell, the central shell and the second side shell are plastics.

Preferably, said first side shell, said center shell and said second side shell are each formed by injection molding.

Preferably, the speed regulation assembly further comprises a power negative plate, a positive connecting plate, a power positive plate, a connecting movable contact plate and a speed-increasing movable contact plate, the connecting movable contact plate and the speed-increasing movable contact plate are respectively in rotating connection with the movable contact frame, and the movable contact frame and the power negative plate are respectively and electrically connected with two poles of the motor; the moving contact comprises a first moving contact arranged at one end of the connecting moving contact plate and a second moving contact arranged at one end of the speed-up moving contact plate; the static contact comprises a first static contact arranged on the positive connecting plate and a second static contact arranged on the positive power plate, the first moving contact and the first static contact are arranged just opposite, the second moving contact and the second static contact are arranged just opposite, and the current adjusting part is respectively electrically connected with the positive connecting plate and the positive power plate.

Preferably, the shell body partition plate is provided with at least one connecting hole, and the speed regulating assembly can penetrate through the connecting hole and is electrically connected with the circuit board.

Preferably, the shell partition plate is provided with at least one positioning hole, and the speed regulating assembly can be inserted into the positioning hole.

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 utility model has the advantages that:

the arrangement enables the circuit board and the speed regulation component to be arranged in a separated mode, the influence of factors such as high temperature in the working state of the speed regulation component and sparks generated when the moving contact is abutted to the static contact on the circuit board is reduced, and the service life of the circuit board is effectively prolonged; meanwhile, the safety risk of the circuit board is reduced due to the separation arrangement, so that the distance between the speed regulation component and the circuit board can be reduced by the switch device on the premise of ensuring the safety, and the space occupied by the whole switch is reduced.

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-adjusting switch according to 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 diagram of a push rod assembly according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a second position of the speed adjusting assembly according to the embodiment of the present invention;

fig. 6 is a schematic structural diagram of a third position of the speed adjusting assembly according to the embodiment of the present invention;

fig. 7 is a schematic structural diagram of a first position of the speed adjusting 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 problem solved by the present invention, the technical solutions adopted by the present invention and the technical effects achieved by the present invention clearer, the following will be described in further detail with reference to the accompanying drawings, and obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by the skilled in the art without creative work belong to 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, detachably 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 meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. 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 solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings.

As shown in fig. 1, 2 and 5-7, the present embodiment provides a dc speed regulating switch, which includes 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 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 piece 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 enable an operator to 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, 3, 5 and 6, the speed regulation assembly 300 further includes a negative power plate 330, a positive connection plate 340, a positive power plate 350, a connecting movable contact plate 310 and a speed-up movable contact plate 320, the connecting movable contact plate 310 and the speed-up movable contact plate 320 are respectively rotatably connected with the 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 and 5-7, when the speed regulation assembly 300 is in the first position, both the connecting movable contact plate 310 and the speed-increasing movable contact plate 320 are disconnected, while the connecting movable contact plate 310 shorts 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, 3, and 5-7, 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 movable contact plate 310 is connected, the rotation plane on which the speed-up movable contact plate 320 is connected, and the direction in which the push rod assembly 200 reciprocates are parallel to each other, and both the movable contact plate 310 and the speed-up movable contact plate 320 are in contact with 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. 2-4 and 7, the push rod assembly 200 includes 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 connected with a moving contact plate 310 and an acceleration moving contact plate 320 in a press-fit manner; 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. Due to the arrangement of the extension spring 210, when an operator does not push the push rod member 220, the first moving contact 311 is far away from the first fixed contact 341, the second moving contact 321 is far away from the second fixed contact 351, and the negative power plate 330 and the positive power plate 350 are in a disconnected state. 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 stationary contact 331, and the third stationary 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. 2-4, 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 continued reference to fig. 2 and 3, 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 power negative plate 330, the positive connecting plate 340, the power positive 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. 2-4 and 7, the speed adjusting assembly 300 is located at the second position, the push ram 222 is connected to the movable contact plate 310 in a crimping 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 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. 2, 3 and 6, the speed-regulating assembly 300 is located at the third position, the second movable contact 321 abuts against the second fixed 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. 2 and 7, the speed regulation 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 fixed 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 is obvious that the above embodiments of the present invention are only 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

1. A DC speed-regulating switch, comprising:

a housing;

the speed regulation assembly (300) comprises a motor, a moving contact and a fixed contact, and when the moving contact abuts against/leaves the fixed contact, the position of the speed regulation assembly (300) is changed, so that the rotating speed of the motor is changed;

a circuit board (400) mounted within the housing;

the circuit board is characterized in that a circuit board cavity (110) and a speed regulating part cavity are formed in the shell, a shell partition plate used for separating the circuit board cavity (110) from the speed regulating part cavity is arranged in the middle of the shell, the circuit board (400) is installed in the circuit board cavity (110), and the moving contact and the fixed contact are installed in the speed regulating part cavity.

2. The dc speed regulation switch of claim 1, wherein the speed regulation assembly (300) further comprises a current regulator (360), wherein in the first position, the positive power supply is open circuited to the negative power supply, and the positive motor is short circuited to the negative motor; 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.

3. The dc speed regulating switch according to claim 2, 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.

4. A dc speed regulating switch according to claim 1, wherein said housing is composed of a first side housing (101), a center housing (102) and a second side housing (103) which are sequentially spliced, said first side housing (101) and said center housing (102) are spliced to form said switchboard cavity (110), and said center housing (102) and said second side housing (103) are spliced to form said speed regulating member cavity.

5. A DC speed regulation switch according to claim 4, characterized in that the material of the first side casing (101), the centre casing (102) and the second side casing (103) is plastic.

6. A DC speed switch according to claim 4, characterized in that said first side casing (101), said central housing (102) and said second side casing (103) are all injection molded.

7. The direct-current speed regulation switch of claim 2, 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; the moving contact comprises a first moving contact (311) arranged at one end of the connecting moving contact plate (310) and a second moving contact (321) arranged at one end of the speed-up moving contact plate (320); the static contacts comprise a first static contact (341) arranged on the positive connecting plate (340) and a second static contact (351) arranged on the positive power plate (350), the first moving contact (311) is arranged opposite to the first static contact (341), the second moving contact (321) is arranged opposite to the second static contact (351), and the current adjusting piece (360) is electrically connected with the positive connecting plate (340) and the positive power plate (350) respectively.

8. The direct current speed regulation switch of claim 1, wherein the housing partition plate is provided with at least one connection hole, and the speed regulation assembly (300) can be inserted into the connection hole and electrically connected with the circuit board (400).

9. The dc speed-regulating switch according to claim 1, wherein the housing partition plate has at least one positioning hole, and the speed-regulating member (300) is inserted into the positioning hole.

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.