A variable-speed electric linear actuator

Abstract

This utility model relates to the field of linear transmission technology, specifically to a variable-speed electric linear actuator. The electric linear actuator includes a motor, a transmission mechanism, an output screw, a control board, multiple trigger switches spaced apart along the axial direction of the output screw, and a slider meshing with the output screw. The motor drives the output screw to rotate via the transmission mechanism, thereby causing the slider to move axially along the output screw. The motor and the multiple trigger switches are all signal-connected to the control board. When the slider moves axially from one end of the output screw to the other, the slider sequentially triggers the trigger switches, and simultaneously the control board controls the motor to change speed. The purpose of this utility model is to provide a variable-speed electric linear actuator that can change speed during operation, thereby solving the problem of sofa lifting and lowering (lying down) speed in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of linear transmission technology, specifically to a variable speed electric push rod. Background Technology

[0002] An electric linear actuator is an electric drive device that converts the rotary motion of a motor into the linear reciprocating motion of a linear actuator. Waterproofing is an essential function of electric linear actuators in many applications, especially in livestock farming, such as large-scale pig farms or chicken farms, where they are widely used to control the opening and closing of ventilation windows, the adjustment of deflectors, and mobile automatic feeding troughs.

[0003] Currently, the electric push rods of some functional sofas move relatively quickly during the lifting and lowering (lying down) process. Since most users are elderly, excessive speed during these processes can easily cause discomfort and accidents, thus affecting the user experience and comfort. The electric push rods need to slow down during this process, but existing electric push rods do not have this function, which causes inconvenience to users. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this utility model is to provide a variable speed electric push rod that can change speed during operation, so as to solve the problem of sofa lifting and lowering (lying down) speed in the existing technology.

[0005] This utility model is achieved through the following technical solution:

[0006] A variable-speed electric linear actuator includes a motor, a transmission mechanism, an output screw, a control board, a plurality of trigger switches spaced apart along the axial direction of the output screw, and a slider meshing with the output screw. The motor drives the output screw to rotate through the transmission mechanism, thereby causing the slider to move axially along the output screw. The motor and the plurality of trigger switches are all signal-connected to the control board. When the slider moves axially from one end of the output screw to the other end, the slider triggers the switches in sequence while the control board controls the motor to change speed.

[0007] The control board includes a control circuit, which includes: MCU, configured to generate pulse width modulation control signals based on operating logic; The H-bridge power drive module is electrically connected to the output port of the MCU and is used to drive the motor according to the control signal. The H-bridge power drive module includes two upper transistor switches and two lower transistor switches. A gate drive module is located between the MCU and the H-bridge power drive module, and is used to amplify the control signal output by the MCU to drive the switching transistor of the H-bridge power drive module; The detection module has its input terminal electrically connected to the output terminal of the H-bridge power drive module and its output terminal electrically connected to a signal input port of the MCU. It is configured to allow the MCU to change the input voltage of the motor when the trigger switch is triggered. The current sampling module includes a sampling resistor connected in series in the ground path of the lower transistor switch of the H-bridge power drive module. Its sampling point is electrically connected to another signal input port of the MCU and is configured to detect the current flowing through the motor.

[0008] The detection module includes: A voltage divider resistor network is connected to the output of the H-bridge; The PNP transistor has a base that receives a back electromotive force signal through the voltage divider resistor network, an emitter that is connected to a positive power supply, and a collector that is connected to the signal input port of the MCU as an output. The PNP transistor acts as a voltage comparator.

[0009] The upper switch of the H-bridge power drive module is a P-channel MOSFET, and the lower switch is an N-channel MOSFET.

[0010] The gate drive module includes an NPN transistor and a pull-up resistor for driving the P-channel MOSFET. The control signal output by the MCU controls the conduction and cutoff of the NPN transistor. When the NPN transistor is on, the gate voltage of the P-channel MOSFET is pulled low to turn it on. When the NPN transistor is off, the gate voltage of the P-channel MOSFET is pulled high through the pull-up resistor to turn it off.

[0011] An RC low-pass filter module is also provided between the sampling point of the current sampling module and the signal input port of the MCU.

[0012] The electric push rod further includes a guide post arranged along the axial direction of the output screw, and the slider is slidably connected to the guide post.

[0013] The guide post has a hollow structure, the slider is slidably sleeved on the guide post, and the output screw is located inside the guide post.

[0014] The electric actuator also includes a gearbox, and the transmission mechanism, one end of the output screw, and the output end of the motor are all located inside the gearbox. The motor is mounted on one side of the gearbox, and the other end of the output screw protrudes out of the other side of the gearbox.

[0015] The gearbox is also equipped with a bearing, which is sleeved on one end of the output screw.

[0016] The beneficial effects of this utility model are: This utility model discloses a variable-speed electric push rod, which uses multiple trigger switches spaced apart along the axial direction of the output screw. The two outermost trigger switches control the upper and lower limits of the stroke. When the slider reaches the position of the remaining trigger switches, the switches are triggered. The control board receives a feedback signal and reduces the output voltage, thereby changing the motor speed and reducing the push rod speed to achieve the desired deceleration effect, thus solving the problem of sofa lifting and lowering (lying down) speed in the prior art. Attached Figure Description

[0017] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0018] Figure 1 This is a partial structural schematic diagram of the present invention.

[0019] Figure 2 This is a partial circuit diagram of the control circuit of this utility model.

[0020] Figure 3 This is a partial circuit diagram of the control circuit of this utility model.

[0021] Figure 4 This is a partial circuit diagram of the control circuit of this utility model.

[0022] Figure 5 This is a partial circuit diagram of the control circuit of this utility model.

[0023] Figure Labels Motor--101, Transmission mechanism--102, Output screw--103, Slider--104, Trigger switch--105, Guide column--106, Gearbox--107, Bearing--108. Detailed Implementation

[0024] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0025] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0027] Example 1 like Figure 1 As shown, this embodiment discloses a variable-speed electric linear actuator, comprising a motor, a transmission mechanism, an output screw, a control board, a plurality of trigger switches spaced apart along the axial direction of the output screw, and a slider meshing with the output screw. The motor drives the output screw to rotate through the transmission mechanism, thereby causing the slider to move axially along the output screw. The motor and the plurality of trigger switches are all signal-connected to the control board. When the slider moves axially from one end of the output screw to the other end, the slider touches the trigger switches in sequence while the control board controls the motor to change speed.

[0028] Specifically, the electric actuator further includes a guide post arranged along the axial direction of the output screw, and the slider is slidably connected to the guide post. The guide post has a hollow structure, the slider is slidably fitted onto the guide post, and the output screw is located inside the guide post.

[0029] By setting guide posts, the stability of the slider during axial movement can be improved.

[0030] The electric linear actuator further includes a gearbox, and the transmission mechanism, one end of the output screw, and the output end of the motor are all located inside the gearbox. The motor is mounted on one side of the gearbox, and the other end of the output screw protrudes from the other side of the gearbox. In this embodiment, the transmission mechanism is preferably a gear set. By providing a gearbox, the precision components inside the electric linear actuator can be protected.

[0031] The gearbox is also equipped with a bearing, which is sleeved on one end of the output screw to improve the rotation accuracy of the output screw.

[0032] Example 2 like Figures 2 to 5 As shown, the control board in this embodiment includes a control circuit, which includes: MCU, configured to generate pulse width modulation control signals based on operating logic; The H-bridge power drive module is electrically connected to the output port of the MCU and is used to drive the motor according to the control signal. The H-bridge power drive module includes two upper transistor switches and two lower transistor switches. A gate drive module is located between the MCU and the H-bridge power drive module, and is used to amplify the control signal output by the MCU to drive the switching transistor of the H-bridge power drive module; The detection module has its input terminal electrically connected to the output terminal of the H-bridge power drive module and its output terminal electrically connected to a signal input port of the MCU. It is configured to allow the MCU to change the input voltage of the motor when the trigger switch is triggered. The current sampling module includes a sampling resistor connected in series in the ground path of the lower transistor switch of the H-bridge power drive module. Its sampling point is electrically connected to another signal input port of the MCU and is configured to detect the current flowing through the motor.

[0033] In this embodiment, the detection module includes: A voltage divider resistor network is connected to the output of the H-bridge; The PNP transistor has a base that receives a back electromotive force signal through the voltage divider resistor network, an emitter that is connected to a positive power supply, and a collector that is connected to the signal input port of the MCU as an output. The PNP transistor acts as a voltage comparator.

[0034] Furthermore, the upper switch of the H-bridge power drive module is a P-channel MOSFET, and the lower switch is an N-channel MOSFET.

[0035] Furthermore, in the gate driving module, the part used to drive the P-channel MOSFET includes an NPN transistor and a pull-up resistor; the control signal output by the MCU controls the conduction and cutoff of the NPN transistor. When the NPN transistor is on, the gate voltage of the P-channel MOSFET is pulled down to a low level to turn it on; when the NPN transistor is off, the gate voltage of the P-channel MOSFET is pulled up to a high level through the pull-up resistor to turn it off.

[0036] Furthermore, an RC low-pass filter module is also provided between the sampling point of the current sampling module and the signal input port of the MCU.

[0037] In summary, this embodiment of a variable-speed electric push rod uses multiple trigger switches spaced apart along the axial direction of the output screw. The two outermost trigger switches control the upper and lower limits of the stroke. When the slider reaches the position of the remaining trigger switches, the switches are triggered, the control board receives a feedback signal, and reduces the output voltage. The motor speed changes, and the push rod speed decreases to achieve the desired deceleration effect, thereby solving the problem of sofa lifting and lowering (lying down) speed in the prior art.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the essence and scope of the technical solutions of this utility model.

Claims

1. A variable-speed electric linear actuator, comprising a motor, a transmission mechanism, an output screw, and a slider meshing with the output screw, wherein the motor drives the output screw to rotate via the transmission mechanism to cause the slider to move axially along the output screw, characterized in that, It also includes a control board and a plurality of trigger switches spaced apart along the axial direction of the output screw, wherein the motor and the plurality of trigger switches are all signal connected to the control board; As the slider moves axially from one end of the output screw to the other, it sequentially touches the trigger switch while the control board controls the motor to change speed.

2. The variable-speed electric linear actuator according to claim 1, characterized in that, The control board includes a control circuit, which includes: MCU, configured to generate pulse width modulation control signals based on operating logic; The H-bridge power drive module is electrically connected to the output port of the MCU and is used to drive the motor according to the control signal. The H-bridge power drive module includes two upper transistor switches and two lower transistor switches. A gate drive module is located between the MCU and the H-bridge power drive module, and is used to amplify the control signal output by the MCU to drive the switching transistor of the H-bridge power drive module; The detection module has its input terminal electrically connected to the output terminal of the H-bridge power drive module and its output terminal electrically connected to a signal input port of the MCU. It is configured to allow the MCU to change the input voltage of the motor when the trigger switch is triggered. The current sampling module includes a sampling resistor connected in series in the ground path of the lower transistor switch of the H-bridge power drive module. Its sampling point is electrically connected to another signal input port of the MCU and is configured to detect the current flowing through the motor.

3. A variable-speed electric actuator according to claim 2, characterized in that, The detection module includes: A voltage divider resistor network is connected to the output of the H-bridge; The PNP transistor has a base that receives a back electromotive force signal through the voltage divider resistor network, an emitter that is connected to a positive power supply, and a collector that is connected to the signal input port of the MCU as an output. The PNP transistor acts as a voltage comparator.

4. A variable-speed electric actuator according to claim 2, characterized in that, The upper switch of the H-bridge power drive module is a P-channel MOSFET, and the lower switch is an N-channel MOSFET.

5. A variable-speed electric actuator according to claim 4, characterized in that, The gate drive module includes an NPN transistor and a pull-up resistor for driving the P-channel MOSFET. The control signal output by the MCU controls the conduction and cutoff of the NPN transistor. When the NPN transistor is on, the gate voltage of the P-channel MOSFET is pulled low to turn it on. When the NPN transistor is off, the gate voltage of the P-channel MOSFET is pulled high through the pull-up resistor to turn it off.

6. A variable-speed electric actuator according to claim 2, characterized in that, An RC low-pass filter module is also provided between the sampling point of the current sampling module and the signal input port of the MCU.

7. A variable-speed electric linear actuator according to claim 1, characterized in that, The electric push rod also includes a guide post arranged along the axial direction of the output screw, and the slider is slidably connected to the guide post.

8. A variable-speed electric linear actuator according to claim 7, characterized in that, The guide post has a hollow structure, the slider is slidably sleeved on the guide post, and the output screw is located inside the guide post.

9. A variable-speed electric linear actuator according to claim 1, characterized in that, The electric actuator also includes a gearbox, and the transmission mechanism, one end of the output screw, and the output end of the motor are all located inside the gearbox. The motor is mounted on one side of the gearbox, and the other end of the output screw protrudes out of the other side of the gearbox.

10. A variable-speed electric linear actuator according to claim 9, characterized in that, The gearbox is also equipped with a bearing, which is sleeved on one end of the output screw.

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