阅读说明：本技术 直流马达控制装置 (DC motor control device ) 是由 王丰贺 于 2018-06-29 设计创作，主要内容包括：一种直流马达控制装置,包含第一电极端、第二电极端、马达开关单元,及控制单元。所述马达开关单元包括受驱动而切换于第一状态及第二状态间的马达开关,所述马达开关具有电连接直流马达的第一端,及电连接所述第二电极端的第二端,于所述第一状态,所述第一端电连接所述第二端,使所述直流马达能通电而运转,于所述第二状态,所述第一端与所述第二端间呈断路,使所述直流马达停止运转。所述控制单元电连接于所述第一电极端与所述第二电极端间,并控制驱动所述马达开关切换于所述第一状态及所述第二状态。通过将所述控制单元避开所述直流马达的大电流路径设置,可以使用较小尺寸的元件实施所述控制单元,因此可以缩减产品体积。(A DC motor control device comprises a first electrode end, a second electrode end, a motor switch unit and a control unit. The motor switch unit comprises a motor switch which is driven to switch between a first state and a second state, the motor switch is provided with a first end electrically connected with the direct current motor and a second end electrically connected with the second electrode end, the first end is electrically connected with the second end in the first state to enable the direct current motor to be electrified and operated, and the first end and the second end are in an open circuit in the second state to enable the direct current motor to stop operating. The control unit is electrically connected between the first electrode end and the second electrode end and controls and drives the motor switch to switch between the first state and the second state. By arranging the control unit away from the large current path of the dc motor, the control unit can be implemented using smaller-sized components, and thus the product volume can be reduced.)

1. A kind of direct current motor controlling device, is suitable for controlling the direct current motor, include the first electrode end and second electrode end;

the first electrode end and the second electrode end are suitable for receiving a direct current power supply in a matched mode;

the method is characterized in that:

the first electrode end is electrically connected with the direct current motor;

the direct current motor control device also comprises a motor switch unit and a control unit;

the motor switch unit comprises a motor switch which is driven to switch between a first state and a second state, the motor switch is provided with a first end electrically connected with the direct current motor and a second end electrically connected with the second electrode end, the first end is electrically connected with the second end in the first state to enable the direct current motor to be electrified and operated, and the first end and the second end are in an open circuit in the second state to enable the direct current motor to stop operating;

the control unit is electrically connected between the first electrode end and the second electrode end and controls the motor switch unit to drive the motor switch to be switched between the first state and the second state.

2. The direct current motor control device according to claim 1, characterized in that:

the motor switch unit further comprises a switch driver having a first end and a second end electrically connected to the second electrode end,

the control unit includes a first control module having:

a first switch having a first end and a second end electrically connected to the first electrode end and the second electrode end, respectively, and

a first transistor having a first terminal electrically connected to the first terminal of the switch driver, a second terminal electrically connected to the first electrode terminal, and a control terminal electrically connected to the second terminal of the first switch,

the first switch is switched between an open circuit and a short circuit to control the first transistor to be switched between a conductive state and a non-conductive state, when the first transistor is conductive, the switch driver drives the motor switch to be switched between the first state, and when the first transistor is non-conductive, the switch driver drives the motor switch to be switched between the second state.

3. The direct current motor control device according to claim 2, characterized in that: the direct current motor control device also comprises a first overload protection module electrically connected between the first electrode end and the direct current motor, wherein the first overload protection module detects the current of the direct current motor and controls the first transistor to be not conducted when the current is overloaded.

4. The direct current motor control device according to claim 3, characterized in that: the first overload protection module includes:

a first detecting element electrically connected between the first electrode and the DC motor for detecting the current of the DC motor and outputting a first control signal, an

The first silicon controlled rectifier comprises an anode end electrically connected with the second end of the first switch, a cathode end electrically connected with the first electrode end, and a trigger end for receiving the first control signal.

5. The direct current motor control device according to claim 2, characterized in that: the switch driver has an inductor electrically connected between the first terminal of the first transistor and the second electrode terminal.

6. The direct current motor control device according to claim 1, characterized in that:

the motor switch unit further includes a switch driver having a first end and a second end, the switch driver driving the motor switch to the first state when a current flows between the first end and the second end, the switch driver driving the motor switch to the second state when no current flows,

the control unit comprises a first control module electrically connected between the first electrode end and the first end of the switch driver, and a second control module electrically connected between the second electrode end and the second end of the switch driver,

the first control module has:

a first switch having a first end and a second end electrically connected to the first electrode end and the second electrode end, respectively,

a first transistor having a first terminal electrically connected to the first terminal of the switch driver, a second terminal electrically connected to the first electrode terminal, and a control terminal electrically connected to the second terminal of the first switch, an

A first diode having an anode terminal electrically connected to the first electrode terminal and a cathode terminal electrically connected to the first terminal of the switch driver,

the second control module has:

a second switch having a first end and a second end electrically connected to the second electrode end and the first electrode end, respectively,

a second transistor having a first terminal electrically connected to the second terminal of the switch driver, a second terminal electrically connected to the second electrode terminal, and a control terminal electrically connected to the second terminal of the second switch, an

A second diode having an anode terminal electrically connected to the second electrode terminal and a cathode terminal electrically connected to the second terminal of the switch driver,

when the first switch is open, the first transistor can be conducted to make current flow from the first end to the second end, when the first switch is short-circuited, the first transistor is not conducted,

when the second switch is open, the second transistor can be conducted to enable current to flow from the first end to the second end, and when the second switch is short-circuited, the second transistor is not conducted.

7. The direct current motor control device according to claim 6, characterized in that: the dc motor control device further includes:

the first overload protection module is electrically connected between the first electrode end and the direct current motor, detects the current of the direct current motor and controls the first transistor to be not conducted when the current is overloaded; and

and the second overload protection module is electrically connected between the second electrode end and the direct current motor, detects the current of the direct current motor and controls the second transistor to be not conducted when the current is overloaded.

8. The direct current motor control device according to claim 7, characterized in that:

the first overload protection module includes:

a first detecting element electrically connected between the first electrode and the DC motor for detecting the current of the DC motor and outputting a first control signal, an

A first silicon controlled rectifier including an anode terminal electrically connected to the second terminal of the first switch, a cathode terminal electrically connected to the first electrode terminal, and a trigger terminal for receiving the first control signal,

the second overload protection module includes:

a second detecting element electrically connected between the second electrode terminal and the DC motor for detecting the current of the DC motor and outputting a second control signal, an

And the second silicon controlled rectifier comprises an anode end electrically connected with the second end of the second switch, a cathode end electrically connected with the second electrode end, and a trigger end for receiving the second control signal.

9. The direct current motor control device according to claim 1, characterized in that:

the motor switch further has a third terminal, the first terminal is switched to be electrically connected between the second terminal and the third terminal, and in the second state, the first terminal is electrically connected to the third terminal,

the direct current motor control device further comprises a positioning switch, wherein the positioning switch is electrically connected between the first electrode end and the third end of the motor switch and is controlled to switch between short circuit and open circuit.

10. The direct current motor control device according to claim 1, characterized in that: the motor switch unit is a relay switch or a metal oxide semiconductor field effect transistor.

Technical Field

The present invention relates to a control device, and more particularly, to a dc motor control device.

Background

Fig. 1 shows a conventional dc motor control circuit suitable for controlling a motor 19, which includes a first terminal 11, a second terminal 12, an upper limit switch 13, a lower limit switch 14, an upper diode 15, and a lower diode 16. The motor 19 can be used to drive a screw (not shown) in rotation to engage a nut (not shown).

The first end 11 and the second end 12 are used for receiving a direct current power supply capable of changing polarity, when in general use, the current flows through the motor 19, the upper limit switch 13 and the lower limit switch 14, so that the motor 19 rotates forward or reversely according to the polarity of the power supply and drives the screw to drive the screw to move up or down, when the screw is driven to reach an upper limit position, the upper limit switch 13 is triggered to break the circuit, at the moment, only when the polarity of the second end is positive, the current can form a loop through the lower limit switch 14, the upper diode 15 and the motor 19, therefore, the motor can be limited to drive the screw to move down and cannot move up any more, conversely, when the screw is driven to reach a lower limit position, the lower limit switch 14 is triggered to break the circuit, at this time, only when the polarity of the first end is positive, the current can form a loop through the motor 19, the upper limit switch 13 and the lower diode 16, so that the motor 19 is limited to drive the nut to move upwards but not to move downwards, and thus, the limit position of the nut can be limited according to actual requirements.

However, since the upper limit switch 13, the lower limit switch 14, the upper diode 15, and the lower diode 16 for controlling the current flow are all located on the large current path of the motor 19, a large-sized device with high current resistance is required to be implemented, so that the overall size is large, and it is difficult to meet the current demand for miniaturization of the circuit.

Disclosure of Invention

The invention aims to provide a DC motor control device with small volume.

The invention relates to a direct current motor control device, which is suitable for controlling a direct current motor and comprises a first electrode end, a second electrode end, a motor switch unit and a control unit.

The first electrode end and the second electrode end are suitable for being matched with each other to receive a direct current power supply, and the first electrode end is electrically connected with the direct current motor.

The motor switch unit comprises a motor switch which is driven to switch between a first state and a second state, the motor switch is provided with a first end electrically connected with the direct current motor and a second end electrically connected with the second electrode end, the first end is electrically connected with the second end in the first state to enable the direct current motor to be electrified and operated, and the first end and the second end are in an open circuit in the second state to enable the direct current motor to stop operating.

The control unit is electrically connected between the first electrode end and the second electrode end and controls the motor switch unit to drive the motor switch to be switched between the first state and the second state.

The direct current motor control device further comprises a switch driver, wherein the switch driver is provided with a first end and a second end electrically connected with the second electrode end.

The control unit comprises a first control module, and the first control module is provided with a first switch and a first transistor.

The first switch has a first end and a second end electrically connected to the first electrode end and the second electrode end, respectively.

The first transistor is provided with a first end electrically connected with the first end of the switch driver, a second end electrically connected with the first electrode end, and a control end electrically connected with the second end of the first switch.

The first switch is switched between an open circuit and a short circuit to control the first transistor to be switched between a conductive state and a non-conductive state, when the first transistor is conductive, the switch driver drives the motor switch to be switched between the first state, and when the first transistor is non-conductive, the switch driver drives the motor switch to be switched between the second state.

The direct current motor control device further comprises a first overload protection module electrically connected between the first electrode end and the direct current motor, wherein the first overload protection module detects the current of the direct current motor and controls the first transistor to be not conducted when the current is overloaded.

In the dc motor control device of the present invention, the first overload protection module includes a first detection element and a first silicon controlled rectifier.

The first detecting element is electrically connected between the first electrode end and the direct current motor, detects the current of the direct current motor and outputs a first control signal.

The first silicon controlled rectifier comprises an anode end electrically connected with the second end of the first switch, a cathode end electrically connected with the first electrode end, and a trigger end for receiving the first control signal.

In the dc motor control device of the present invention, the switch driver has an inductor electrically connected between the first terminal of the first transistor and the second electrode terminal.

The direct current motor control device further comprises a switch driver, wherein the switch driver is provided with a first end and a second end, when current flows between the first end and the second end, the switch driver drives the motor switch to be switched to the first state, and when no current flows, the switch driver drives the motor switch to be switched to the second state.

The control unit comprises a first control module electrically connected between the first electrode end and the first end of the switch driver, and a second control module electrically connected between the second electrode end and the second end of the switch driver.

The first control module is provided with a first switch, a first transistor and a first diode.

The first switch has a first end and a second end electrically connected to the first electrode end and the second electrode end, respectively.

The first transistor is provided with a first end electrically connected with the first end of the switch driver, a second end electrically connected with the first electrode end, and a control end electrically connected with the second end of the first switch.

The first diode has an anode terminal electrically connected to the first electrode terminal, and a cathode terminal electrically connected to the first terminal of the switch driver.

The second control module is provided with a second switch, a second transistor and a second diode.

The second switch is provided with a first end and a second end which are respectively and electrically connected with the second electrode end and the first electrode end.

The second transistor has a first end electrically connected to the second end of the switch driver, a second end electrically connected to the second electrode terminal, and a control end electrically connected to the second end of the second switch.

The second diode has an anode terminal electrically connected to the second electrode terminal, and a cathode terminal electrically connected to the second terminal of the switch driver.

When the first switch is open, the first transistor can be conducted to enable current to flow from the first end to the second end, and when the first switch is short, the first transistor is not conducted.

When the second switch is open, the second transistor can be conducted to enable current to flow from the first end to the second end, and when the second switch is short-circuited, the second transistor is not conducted.

The DC motor control device also comprises a first overload protection module and a second overload protection module.

The first overload protection module is electrically connected between the first electrode end and the direct current motor, detects the current of the direct current motor and controls the first transistor to be not conducted when the current is overloaded.

The second overload protection module is electrically connected between the second electrode end and the direct current motor, detects the current of the direct current motor and controls the second transistor to be not conducted when the current is overloaded.

In the dc motor control device of the present invention, the first overload protection module includes a first detection element and a first scr.

The first detecting element is electrically connected between the first electrode end and the direct current motor, detects the current of the direct current motor and outputs a first control signal.

The first silicon controlled rectifier comprises an anode end electrically connected with the second end of the first switch, a cathode end electrically connected with the first electrode end, and a trigger end for receiving the first control signal.

The second overload protection module comprises a second detection element and a second silicon controlled rectifier.

The second detecting element is electrically connected between the second electrode end and the direct current motor, detects the current of the direct current motor and outputs a second control signal.

The second silicon controlled rectifier comprises an anode end electrically connected with the second end of the second switch, a cathode end electrically connected with the second electrode end, and a trigger end for receiving the second control signal.

In the dc motor control device according to the present invention, the motor switch further includes a third terminal, the first terminal is switched to be electrically connected between the second terminal and the third terminal, and the first terminal is electrically connected to the third terminal in the second state.

The direct current motor control device further comprises a positioning switch, wherein the positioning switch is electrically connected between the first electrode end and the third end of the motor switch and is controlled to switch between short circuit and open circuit.

In the dc motor control device of the present invention, the motor switch unit is a relay switch or a mosfet.

The invention has the beneficial effects that: by disposing the control unit between the first electrode terminal and the second electrode terminal and avoiding the large current path of the dc motor, the control unit can be implemented by using smaller-sized components, thereby reducing the product size and meeting the current demand for circuit miniaturization.

Drawings

FIG. 1 is a schematic circuit diagram of a prior art DC motor control circuit;

FIG. 2 is a circuit schematic of a first embodiment of the DC motor control circuit of the present invention;

FIG. 3 is a circuit schematic of a second embodiment of the DC motor control circuit of the present invention; and

fig. 4 is a circuit diagram of a dc motor control circuit according to a third embodiment of the present invention.

Detailed Description

Before the present invention is described in detail, it should be noted that in the following description, like elements are represented by like reference numerals.

Referring to fig. 2, a first embodiment of the dc motor control apparatus of the present invention is adapted to control a dc motor 9 of an electric cylinder (not shown), and includes an electrode unit 2, a motor switching unit 3, and a control unit 4.

The electrode unit 2 comprises a first electrode terminal IN1 and a second electrode terminal IN2, the first electrode terminal IN1 and the second electrode terminal IN2 are adapted to receive a dc power source, and the first electrode terminal IN1 is electrically connected to the dc motor 9.

The motor switch unit 3 includes a motor switch 31 driven to switch between a first state and a second state, and a switch driver 32. The motor switch unit 3 is preferably a relay switch.

The motor switch 31 has a first terminal 311 electrically connected to the dc motor 9, a second terminal 312 electrically connected to the second electrode IN2, and a third terminal 313, wherein the first terminal 311 is electrically connected to the second terminal 312 or the third terminal 313 IN a switchable manner, IN the first state, the first terminal 311 is electrically connected to the second terminal 312 to enable the dc motor 9 to be energized for operation, and IN the second state, the first terminal 311 is disconnected from the second terminal 312 (for example, the first terminal 311 is electrically connected to the third terminal 313) to disable the dc motor 9. In addition, the motor switch 31 of the present embodiment can only have the first end 311 and the second end 312, so as to achieve the requirement of turning on or off the dc motor 9.

The switch driver 32 has a first terminal 321, a second terminal 322 electrically connected to the second electrode terminal IN2, and an inductor 323.

The control unit 4 is electrically connected between the first electrode terminal IN1 and the second electrode terminal IN2, and controls the motor switch unit 3 to drive the motor switch 31 to switch between the first state and the second state. The control unit 4 includes a first control module 41, and the first control module 41 has a first switch 411, a first transistor 412, a first buffer resistor 413, and a first control step-down resistor 414.

The first switch 411 has a first terminal 416 and a second terminal 417 electrically connected to the first electrode terminal IN1 and the second electrode terminal IN2, respectively. The first switch 411 is switched between an open state and a short state to control the first transistor 412 to be switched between a conductive state and a non-conductive state, when the first transistor 412 is conductive, the switch driver 32 drives the motor switch 31 to be switched between the first state, and when the first transistor 412 is non-conductive, the switch driver 32 drives the motor switch 31 to be switched between the second state.

The first switch 411 may be a limit switch, and is implemented by using a micro switch, a reed switch, a photoelectric switch, a temperature switch, a vibration switch, etc., but the first switch 411 may also be controlled by an external switch control circuit (not shown), and the switch control circuit may control to switch the first switch 411 to open or short circuit according to the requirements of whether the circuit is overheated, whether the dc motor 9 is overheated, whether the vibration is too large, etc.

The first transistor 412 has a first terminal electrically connected to the first terminal 321 of the switch driver 32, a second terminal electrically connected to the first electrode terminal IN1, and a control terminal electrically connected to the second terminal 417 of the first switch 411. In the embodiment, the first transistor 412 is an NPN bipolar transistor (BJT), the first terminal is a Collector (Collector), the second terminal is an Emitter (Emitter), and the control terminal is a Base (Base), however, the first transistor 412 can also use an N-type Metal-Oxide-Semiconductor Field effect transistor (MOSFET), or a PNP bipolar transistor or a P-type Metal-Oxide-Semiconductor Field effect transistor according to actual requirements, and the connection of the polarity adjusting circuit can vary the used components according to actual requirements, which is not limited thereto.

Two ends of the first buffer resistor 413 are electrically connected to the second end 417 of the first switch 411 and the control end of the first transistor 412, respectively. Two ends of the first control step-down resistor 414 are electrically connected to the second end 417 of the first switch 411 and the second electrode end IN2, respectively.

IN practical applications, the dc power source may have a fixed polarity, and a negative voltage (low potential) is inputted to the first electrode terminal IN1, and a positive voltage (high potential) is inputted to the second electrode terminal IN 2.

When the first switch 411 is turned off, the voltage at the control terminal of the first transistor 412 is high, so that the first transistor 412 is turned on, a current can form a loop through the switch driver 32 and the first transistor 412, the current flows through the inductor 323, so that the switch driver 32 drives the motor switch 31 to be switched to the first state, and the dc motor 9 can be energized to operate and operate the electric cylinder.

When the electric cylinder operates to reach a predetermined position to trigger the first switch 411 to close and short circuit, or the external switch control circuit controls the first switch 411 to close and short circuit, the control end voltage of the first transistor 412 is pulled down to a low level to make the first transistor 412 non-conductive, the inductor 32 has no current passing through, the motor switch 31 is switched to the second state, the dc motor 9 is not energized to stop operation, and the electric cylinder stops operating.

Through the above description, the advantages of the present embodiment can be summarized as follows:

firstly, by disposing the control unit 4 between the first electrode terminal IN1 and the second electrode terminal IN2 and avoiding the large current path of the dc motor 9, the control unit 4 can be implemented without using large-sized devices resistant to high current, and furthermore, since the control unit 4 only needs to drive and control the signal of the motor switch unit 3, the amount of current flowing is small, so that the control unit 4 can be implemented by using small-sized devices, the effect of greatly reducing the product volume can be achieved, and according to the actual manufacturing effect, the volume of the control unit 4 can be reduced to be directly disposed IN the electric cylinder, so that the requirement of miniaturization of the current circuit can be met.

Second, by providing the first control step-down resistor 414 and the first buffer resistor 413, a step-down buffer can be provided to protect the first transistor 412.

Referring to fig. 3, a second embodiment of the dc motor control device of the present invention is similar to the first embodiment, and the difference between the second embodiment and the first embodiment is:

the first terminal 311 of the motor switch 31 is electrically connected to the second terminal 312 and the third terminal 313, and in the first state, the first terminal 311 is electrically connected to the second terminal 312, and in the second state, the first terminal 311 is electrically connected to the third terminal 313.

The switch driver 32 drives the motor switch 31 to switch to the first state when a current passes between the first end 321 and the second end 322, and drives the motor switch 31 to switch to the second state when the current does not pass.

The control unit 4 includes the first control module 41 electrically connected between the first electrode terminal IN1 and the first end 321 of the switch driver 32, and a second control module 42 electrically connected between the second electrode terminal IN2 and the second end 322 of the switch driver 32.

The first control module 41 further has a first diode 415, and the first diode 415 has an anode terminal electrically connected to the first electrode terminal IN1, and a cathode terminal electrically connected to the first terminal 321 of the switch driver 32.

When the first switch 411 is turned off, the first transistor 412 is turned on to allow current to flow from the first end to the second end, and when the first switch 411 is short-circuited, the first transistor 412 is turned off.

The second control module 42 has a second switch 421, a second transistor 422, a second buffer resistor 423, a second control step-down resistor 424, and a second diode 425.

The second switch 421 has a first terminal 426 and a second terminal 427 electrically connected to the second electrode terminal IN2 and the first electrode terminal IN1, respectively. When the second switch 421 is turned off, the second transistor 422 can be turned on to allow current to flow from the first end to the second end, and when the second switch 421 is turned off, the second transistor 422 is not turned on.

The second switch 421 can also be a limit switch, and is implemented by using an element such as a micro switch, a reed switch, a photoelectric switch, a temperature switch, a vibration switch, or controlled by the external switch control circuit.

The second transistor 422 has a first terminal electrically connected to the second terminal 322 of the switch driver 32, a second terminal electrically connected to the second electrode terminal IN2, and a control terminal electrically connected to the second terminal 427 of the second switch 421. In the present embodiment, the second transistor 422 is an NPN-type bipolar transistor, the first terminal is a collector, the second terminal is an emitter, and the control terminal is a base, however, the second transistor 422 can also use an N-type mosfet according to actual requirements, or use a PNP-type bipolar transistor, or a P-type mosfet, and adjust the circuit connection according to polarity, which can change the used components according to actual requirements, without being limited thereto.

Two ends of the second buffer resistor 423 are electrically connected to the second end 427 of the second switch 421 and the control end of the second transistor 422, respectively. Two ends of the second control voltage-reducing resistor 424 are electrically connected to the second end 427 of the second switch 421 and the first electrode end IN1, respectively.

The second diode 425 has an anode terminal electrically connected to the second electrode terminal IN2, and a cathode terminal electrically connected to the second terminal 322 of the switch driver 32.

The second embodiment further includes a positioning switch 6, wherein the positioning switch 6 is electrically connected between the first electrode terminal IN1 and the third terminal 313 of the motor switch 31 and is controlled to switch between short-circuit and open-circuit. The positioning switch 6 can be a single-switch for the user to operate and switch, and can also be an electronic switch for the external switch control circuit to control and switch.

IN practical use, the dc power supply may switch the polarity of the voltage provided according to the operation of the user, so that a positive voltage (high potential) and a negative voltage (low potential) are alternately input to the first electrode terminal IN1 and the second electrode terminal IN2, for example, if the first electrode terminal IN1 inputs a positive voltage (high potential) and the second electrode terminal IN2 inputs a negative voltage (low potential), the dc motor 9 can be rotated forward to extend the electric cylinder, and if the first electrode terminal IN1 inputs a negative voltage (low potential) and the second electrode terminal IN2 inputs a positive voltage (high potential), the dc motor 9 can be rotated backward to shorten the electric cylinder.

To illustrate, the first switch 411 and the second switch 421 are both limit switches, when a user intends to operate the dc motor 9 to rotate forward to extend the electric cylinder, the power supply is controlled to make the first electrode IN1 be at a high potential and the second electrode IN2 be at a low potential, at this time, the first switch 411 and the second switch 421 are turned off, a current flows from the first electrode IN1 to the second electrode IN2 through the first diode 415, the switch driver 32 and the second transistor 422 to form a loop, so that the inductor 323 drives the motor switch 31 to switch to the first state, the dc motor 9 is energized to rotate forward, and the electric cylinder is extended.

When the electric cylinder extends to a first predetermined length, the second switch 421 is triggered to short the second switch 421, at this time, the voltage at the control end of the second transistor 422 is pulled to a low potential to make the second transistor 422 non-conductive, so that the circuit loop is broken, the inductor 323 has no current passing through, so that the motor switch 31 is switched to the second state, the direct current motor 9 has no current passing through and stops rotating, and the electric cylinder stops operating, so that the extension length of the electric cylinder can be limited to meet the actual use requirement.

Similarly, when the user wants to operate the dc motor 9 to reverse to shorten the electric cylinder, the power supply is controlled to make the second electrode IN2 high and the first electrode IN1 low, at this time, the first switch 411 and the second switch 421 are turned off, the current flows from the second electrode IN2 to the first electrode IN1 through the second diode 425, the switch driver 32 and the first transistor 412 to form a loop, the motor switch 31 is switched to the first state, the dc motor 9 is turned on to reverse, and the electric cylinder is shortened.

When the electric cylinder shortens to a second predetermined length, the first switch 411 is triggered to short-circuit the first switch 411, at this time, the voltage at the control end of the first transistor 412 is pulled to a low potential to make the first transistor 412 non-conductive, so that the circuit loop is broken, the inductor 323 has no current passing, the motor switch 31 is switched to the second state, the direct current motor 9 has no current passing and stops rotating, and the electric cylinder stops operating, so that the shortened length of the electric cylinder can be limited to meet the actual use requirement.

When the user wants to turn off the dc motor 9 and does not operate any more, the positioning switch 6 can be controlled to be switched to a short circuit, so that the dc motor 9 can be in a self-locking state of being incapable of rotating due to the short circuit, and the electric cylinder is positioned and cannot be easily stretched or pressed by an external force.

Thus, the second embodiment can achieve the same purpose and effect as the first embodiment, and also has the following effects:

first, by providing the first control module 41 and the second control module 42, a forced stopping function of the dc motor 9 during forward rotation and reverse rotation can be provided, and the length of the electric cylinder can be limited according to actual use requirements, or the external switch control circuit can be provided to forcibly stop the forward rotation or reverse rotation of the dc motor 9 under a set condition (such as overheating, reaching a set operation time, limiting unidirectional operation, for example, only forward or backward movement can be performed).

Second, through setting the positioning switch 6, a user can control the dc motor 9 to enter a self-locking state, so that the position of the electric cylinder can be fixed by locking the rotation position of the dc motor 9, and the electric cylinder can be maintained at the position set by the user, thereby solving the problem in the prior art that the electric cylinder is easily elongated or shortened by an external force when the ball screw is applied to the electric cylinder, and in the prior art, a mechanism is mostly used to fix the ball screw to avoid movement, such as using an electromagnetic switch, a clutch, etc., but the above-mentioned methods all have a problem of an excessively large volume, in this embodiment, the dc motor 9 can be brought into the self-locking state only by setting the positioning switch 6, and thus, the circuit miniaturization is maintained.

Referring to fig. 4, a third embodiment of the dc motor control device of the present invention is similar to the second embodiment, and the difference between the third embodiment and the second embodiment is:

the third embodiment further comprises an overload protection unit 5, wherein the overload protection unit 5 comprises a first overload protection module 51 and a second overload protection module 52.

The first overload protection module 51 is electrically connected between the first electrode terminal IN1 and the dc motor 9, detects a current of the dc motor 9, and controls the first transistor 412 to be turned off when the current is overloaded. The first overload protection module 51 includes a first detection element 511, a first silicon controlled rectifier 512, a first overload step-down resistor 513, and a first voltage stabilizing capacitor 514.

The first detecting element 511 is electrically connected between the first electrode terminal IN1 and the dc motor 9, detects a current of the dc motor 9 and outputs a first control signal, and has a first detecting resistor 515, wherein the first detecting resistor 515 includes a first terminal electrically connected to the first electrode terminal IN1 and a second terminal electrically connected to the dc motor 9.

The first Silicon Controlled Rectifier 512 (SCR) includes an anode terminal electrically connected to the second terminal 417 of the first switch 411, a cathode terminal electrically connected to the first electrode terminal IN1, and a trigger terminal electrically connected to the second terminal of the first detecting resistor 515 and receiving the first control signal.

Two ends of the first overload step-down resistor 513 are electrically connected to the second end of the first detection resistor 515 and the trigger end of the first scr 512, respectively.

Two ends of the first voltage-stabilizing capacitor 514 are electrically connected to the first electrode terminal IN1 and the trigger terminal of the first scr 512, respectively.

The second overload protection module 52 is electrically connected between the second electrode terminal IN2 and the dc motor 9, and detects the current of the dc motor 9 and controls the second transistor 422 to be turned off when the current is overloaded. The second overload protection module 52 includes a second detecting element 521, a second scr 522, a second overload step-down resistor 523, and a second voltage-stabilizing capacitor 524.

The second detecting element 521 is electrically connected between the second electrode IN2 and the dc motor 9, detects the current of the dc motor 9 and outputs a second control signal, and has a second detecting resistor 525, wherein the second detecting resistor 525 includes a first end electrically connected to the second electrode IN2 and a second end electrically connected to the dc motor 9.

The second scr 522 includes an anode terminal electrically connected to the second terminal 427 of the second switch 421, a cathode terminal electrically connected to the second electrode terminal IN2, and a trigger terminal electrically connected to the second terminal of the second detection resistor 525 and receiving the second control signal.

Two ends of the second overload step-down resistor 523 are electrically connected to the second end of the second detecting resistor 525 and the trigger end of the second scr 522, respectively.

Two ends of the second voltage-stabilizing capacitor 524 are electrically connected to the second electrode terminal IN2 and the trigger terminal of the second scr 522, respectively.

IN practical use, the dc power supply can be switched between the first electrode terminal IN1 and the second electrode terminal IN2 by user operation to alternately input a positive polarity voltage (high potential) and a negative polarity voltage (low potential) so as to rotate the dc motor 9 forward or backward and extend or shorten the electric cylinder.

Since the function of the control unit 4 is the same as that of the second embodiment, it is not described herein again.

When the user controls the power supply to make the first electrode terminal IN1 at a high potential and the second electrode terminal IN2 at a low potential, at this time, the current forms a loop through the first detection resistor 515, the dc motor 9, and the second detection resistor 525, and a detection voltage is generated at the second end of the second detection resistor 525, when the current is abnormally excessive, the detection voltage is larger than the trigger voltage of the second scr 522, the second scr 522 is turned on, and thus the voltage at the control terminal of the second transistor 422 is pulled to a low level to turn off the second transistor 422, so that the circuit loop of the control unit 4 is opened, when no current flows through the inductor 323, the motor switch 31 is switched to the second state, the dc motor 9 stops operating, and the electric cylinder stops operating.

Similarly, when the user controls the power supply to make the first electrode terminal IN1 be at a low potential and the second electrode terminal IN2 be at a high potential, the current passes through the second detection resistor 525, the dc motor 9 and the first detection resistor 515 to form a loop, and the detection voltage is generated at the second terminal of the first detection resistor 515, when the current is abnormal and excessive, the detection voltage is greater than the trigger voltage of the first scr 512, so that the first scr 512 is turned on, the voltage at the control terminal of the first transistor 412 is pulled to a low potential to make the first transistor 412 not turned on, so that the circuit loop of the control unit 4 is opened, the inductor 323 has no current to pass through, so that the motor switch 31 is switched to the second state, the dc motor 9 stops operating, and the electric cylinder stops operating.

Thus, the third embodiment can achieve the same purpose and effect as the second embodiment, and also has the following effects:

first, by providing the first overload protection module 51 and the second overload protection module 52, the protection stopping function of the dc motor 9 during forward rotation and reverse rotation can be provided, so as to prevent the circuit and the dc motor 9 from being damaged by overheating during overload, thereby achieving the effects of overload protection and prolonging the service life.

Moreover, the first overload protection module 51 and the second overload protection module 52 can also provide a limit switch function, because when the dc motor 9 drives the electric cylinder to a limit position, the electric cylinder cannot move any more, which may cause the dc motor 9 to idle and overload, and when the first overload protection module 51 or the second overload protection module 52 detects the overload, the first transistor 412 or the second transistor 422 is controlled to be non-conductive to stop the rotation of the dc motor 9, which may also achieve the same function as the limit switch.

Second, by providing the first scr 512 and the second scr 522, the scr can be triggered to maintain conduction until the scr is reset, and the first transistor 412 or the second transistor 422 is forced to be locked to be non-conductive when the system is overloaded, so that the motor switch 31 is switched to the second state, and the operation of the dc motor 9 is stopped, that is, the above circuit effect can be achieved by using simple elements, so that the circuit has the advantages of simplified circuit, easy implementation, low cost, and high stability.

In summary, the dc motor control device of the present invention can achieve the purpose of reducing the product volume, and also has the effects of forced stopping, self-locking setting, and overload protection.

The above description is only an example of the present invention, but not intended to limit the scope of the present invention, and all simple equivalent changes and modifications made in the claims and the specification of the present invention are within the scope of the present invention.