Electric height adjusting device and mower

Abstract

The utility model discloses an electric height adjusting device and a mower, the electric height adjusting device comprises a controller, a driving unit in communication connection with the controller, a front shaft supporting unit, a rear shaft supporting unit and a height adjusting unit, the front shaft supporting unit and the rear shaft supporting unit are used for supporting a mower main body, and a first connecting rod is hinged between the height adjusting unit and the front shaft supporting unit; a second connecting rod is hinged between the height adjusting unit and the rear shaft supporting unit, and the driving unit is in driving connection with the height adjusting unit, so that at least one part of the height adjusting unit can move relative to the driving unit; the height adjusting unit can drive the front shaft supporting unit and the rear shaft supporting unit to rotate at the same time through the first connecting rod and the second connecting rod so that the height of a chassis of the mower can be increased or decreased. The electric height adjusting device is simple in structure and convenient to adjust, the height of the front shaft supporting unit and the height of the rear shaft supporting unit can be synchronously adjusted, and the height difference between the front shaft supporting unit and the rear shaft supporting unit after adjustment is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of power tools, and particularly to an electric height adjustment device and a lawn mower. Background Art

[0002] A lawn mower is a commonly used mechanical gardening tool for trimming lawns or grasslands, which can help people complete the lawn mowing work quickly and efficiently. A lawn mower mainly consists of components such as a chassis, an engine, a traveling mechanism, a cutting member, and an operating device. In order to achieve different mowing heights, existing lawn mowers generally come with a height adjustment structure, and the height of the cutting member is adjusted by adjusting the height of the chassis to adapt to the mowing requirements under different lawn conditions.

[0003] However, the chassis height adjustment structure of existing lawn mowers has the following problems: 1. The link assembly that makes up the chassis height adjustment structure is complex in structure and relatively high in cost; 2. The chassis height adjustment structure of most lawn mowers is a stepless adjustment structure, and when the user adjusts, the height cannot be quickly adjusted to a specific gear, and accurate gear adjustment cannot be achieved; 3. Most of the lawn mowers that can perform accurate gear adjustment are manual gear adjustments, with cumbersome operations and low intelligence; 4. For the extremely few lawn mowers that can perform accurate electric gear adjustment, the implementation structure of the electric gear adjustment is relatively complex, occupies a large space, and is costly. Summary of the Invention

[0004] One object of the present application is to provide an electric height adjustment device with a simple structure and convenient adjustment.

[0005] Another object of the present application is to provide a lawn mower.

[0006] To achieve the above objectives, the technical solution adopted in the present application is: an electric height adjustment device, comprising:

[0007] A controller;

[0008] A drive unit, the controller is communicatively connected to the drive unit to control the start and stop of the drive unit;

[0009] A front axle support unit and a rear axle support unit for supporting the lawn mower;

[0010] And a height adjustment unit, a first link is hinged between the height adjustment unit and the front axle support unit, a second link is hinged between the height adjustment unit and the rear axle support unit, the drive unit is drivingly connected to the height adjustment unit, so that at least a part of the height adjustment unit can move relative to the drive unit, and further the height adjustment unit can drive the front axle support unit and the rear axle support unit to rotate simultaneously through the first link and the second link to raise or lower the chassis height of the lawn mower.

[0011] As a preference, the height adjustment unit includes a height adjustment base and a height adjustment bracket. The height adjustment bracket includes a first rod and a second rod which are hinged to each other to form a V-shaped structure. The bottom end of the first rod is connected to the drive unit, and the bottom end of the second rod is connected to the height adjustment base. Two ends of the first connecting rod are respectively hinged to the second rod and the front axle support unit, and two ends of the second connecting rod are respectively hinged to the first rod and the rear axle support unit. Further, the drive unit can drive the bottom end of the first rod to approach or move away from the bottom end of the second rod to drive the first connecting rod and the second connecting rod to rotate, so that the front axle support unit and the rear axle support unit rotate simultaneously to raise or lower the chassis height of the lawn mower.

[0012] As another preference, the drive unit includes a drive motor, a driven screw rod and a sliding block. The driven screw rod is arranged in the height adjustment base and connected to the output shaft of the drive motor. Further, the drive motor can drive the driven screw rod to rotate along its axis. The sliding block is threadedly connected to the driven screw rod and hinged to the bottom end of the first rod. When the drive motor drives the driven screw rod to rotate, the sliding block can move relative to the driven screw rod to drive the bottom end of the first rod to approach or move away from the bottom end of the second rod.

[0013] Further preferably, a through sliding groove is formed in the side wall of the height adjustment base. The extending direction of the sliding groove is the same as that of the driven screw rod. An end portion of the sliding block is embedded in the sliding groove to form a movable end, so that when the sliding block moves relative to the driven screw rod, the movable end moves in the sliding groove.

[0014] Further, the electric height adjustment device further includes a gear position adjustment unit. The gear position adjustment unit is adapted to obtain the displacement of the sliding block and convert it into an electrical signal for transmission to the controller. The controller is adapted to control the drive unit to work or stop according to the electrical signal, so that the sliding block moves a fixed distance relative to the driven screw rod each time.

[0015] Further, the gear position adjustment unit includes a magnetic member, an induction plate and a plurality of Hall sensors. The magnetic member is fixedly installed on the movable end. The induction plate is arranged on the side wall of the height adjustment base and corresponds to the sliding groove. Each Hall sensor is arranged on the induction plate at intervals along the extending direction of the sliding groove. The Hall sensors are communicatively connected to the controller. The Hall sensors are adapted to send an electrical signal to the controller when the magnetic field strength reaches a preset value, and the controller controls the drive motor to stop after receiving the electrical signal.

[0016] Further, the gear shifting adjustment unit includes a switch box, a plurality of micro switches, and a plurality of trigger arms. The switch box is arranged on the side wall of the height adjustment base and corresponds to the sliding groove. Each of the micro switches is arranged in the switch box at intervals along the extending direction of the sliding groove. Each of the trigger arms is arranged in the switch box corresponding to the micro switch. The micro switch is communicatively connected to the controller. The trigger arm is adapted to be pressed by the movable end to trigger the micro switch, so that the micro switch sends an electrical signal to the controller, and the controller controls the driving motor to stop after receiving the electrical signal.

[0017] Further, the front axle support unit includes a front axle connecting member for connecting with the front wheel. A front wheel axle for supporting the mower main body is arranged on the front axle connecting member, and the first connecting rod is hinged on the front axle connecting member; the rear axle support unit includes a rear axle connecting member for connecting with the rear wheel. A rear wheel axle for supporting the mower main body is arranged on the rear axle connecting member, and the second connecting rod is hinged on the rear axle connecting member.

[0018] Further, the connection points of the front wheel, the front wheel axle, and the first connecting rod on the front axle connecting member are arranged in a triangular pattern; the connection points of the rear wheel, the rear wheel axle, and the second connecting rod on the rear axle connecting member are arranged in a triangular pattern.

[0019] The present application also provides a mower, including the above-mentioned electric height adjustment device.

[0020] Compared with the prior art, the beneficial effects of the present application are as follows:

[0021] The electric height adjustment device provided by the present application includes a driving unit and a height adjustment unit. The front axle support unit and the height adjustment unit are connected by a first connecting rod, and the rear axle support unit and the height adjustment unit are connected by a second connecting rod. The driving unit can drive at least a part of the height adjustment unit to move relative to the driving unit, so as to drive the front axle support unit and the rear axle support unit to rotate simultaneously through the first connecting rod and the second connecting rod to raise or lower the chassis height of the mower main body. The overall structure of the electric height adjustment device is simple, and the heights of the front axle support unit and the rear axle support unit can be adjusted simultaneously, so as to ensure that the chassis height of the mower always remains horizontal during the adjustment process and avoid the appearance of a front-rear height difference. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of the electric height adjustment device of the present application.

[0023] Figure 2 It is a schematic structural diagram of the driving unit, the height adjustment unit, and the gear shifting adjustment unit in the electric height adjustment device of the present application.

[0024] Figure 3This is a schematic structural diagram of another embodiment of the drive unit, height adjustment unit, and gear position adjustment unit in the electric height adjustment device of the present application.

[0025] Figure 4 This is a schematic structural diagram of the gear position adjustment unit in the electric height adjustment device of the present application.

[0026] Figure 5 This is a schematic structural diagram of the front axle support unit in the electric height adjustment device of the present application.

[0027] Figure 6 This is a schematic structural diagram of the rear axle support unit in the electric height adjustment device of the present application.

[0028] In the figure: 100, drive unit; 110, drive motor; 120, reduction gearbox; 130, driven screw; 140, sliding block; 141, movable end; 200, height adjustment unit; 210, height adjustment base; 211, sliding groove; 220, height adjustment bracket; 221, first support rod; 222, second support rod; 300, front axle support unit; 310, front wheel axle; 320, front axle connecting piece; 400, rear axle support unit; 410, rear wheel axle; 420, rear axle connecting piece; 500, first connecting rod; 600, second connecting rod; 700, gear position adjustment unit; 710a, magnetic part; 720a, Hall sensor; 730a, induction plate; 710b, switch box; 720b, microswitch; 730b, trigger arm. Detailed implementation manners

[0029] Next, in combination with the detailed implementation manners, the present application will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0030] In the description of the present application, it should be noted that for orientation terms, such as the terms "center", "transverse", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the orientation and position relationships indicated are based on the orientation or position relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of the present application.

[0031] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence.

[0032] As used in the description and claims of this application, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to such process, method, product, or apparatus.

[0033] As Figures 1-6 shown, this application provides an electric height adjustment device for adjusting the chassis height of a lawn mower, which comprises:

[0034] A controller;

[0035] A drive unit 100, the controller is communicatively connected to the drive unit 100 to control the start and stop of the drive unit 100;

[0036] A front axle support unit 300 and a rear axle support unit 400 for supporting the lawn mower;

[0037] And a height adjustment unit 200. A first link 500 is hinged between the height adjustment unit 200 and the front axle support unit 300, and a second link 600 is hinged between the height adjustment unit 200 and the rear axle support unit 400. The drive unit 100 is drivingly connected to the height adjustment unit 200, so that at least a part of the height adjustment unit 200 can move relative to the drive unit 100. Furthermore, the height adjustment unit 200 can drive the front axle support unit 300 and the rear axle support unit 400 to rotate simultaneously through the first link 500 and the second link 600 to raise or lower the chassis height of the lawn mower, enabling the lawn mower to achieve different mowing heights.

[0038] Specifically, as Figures 1-2As shown, the height adjustment unit 200 includes a height adjustment base 210 and a height adjustment bracket 220. The height adjustment bracket 220 is disposed within the height adjustment base 210. The height adjustment bracket 220 includes a first rod 221 and a second rod 222. The top end of the first rod 221 is hinged to the top end of the second rod 222. The bottom end of the first rod 221 is connected to the drive unit 100. The bottom end of the second rod 222 is hinged to the height adjustment base 210, such that the first rod 221 and the second rod 222 form a V-shaped structure. The drive unit 100 can drive the bottom end of the first rod 221 to move back and forth to approach or move away from the bottom end of the second rod 222. A first connecting rod 500 is hinged between the first rod 221 and the rear axle support unit 400, and a second connecting rod 600 is hinged between the second rod 222 and the front axle support unit 300. When the drive unit 100 drives the bottom end of the first rod 221 to move closer to the bottom end of the second rod 222, the first connecting rod 500 and the second connecting rod 600 are driven by the first rod 221 and the second rod 222. The first connecting rod 500 and the second connecting rod 600 can drive the front axle support unit 300 and the rear axle support unit 400 to rotate simultaneously to raise the chassis height of the lawn mower body. When the drive unit 100 drives the bottom end of the first rod 221 to move away from the bottom end of the second rod 222, the first connecting rod 500 and the second connecting rod 600 are driven by the first rod 221 and the second rod 222. The first connecting rod 500 and the second connecting rod 600 can drive the front axle support unit 300 and the rear axle support unit 400 to rotate simultaneously to lower the chassis height of the lawn mower body.

[0039] Further, the drive unit 100 specifically includes a drive motor 110, a driven screw 130, and a sliding block 140. The output end of the drive motor 110 is connected with a reduction gearbox 120. The driven screw 130 is disposed on the reduction gearbox 120 and is in transmission connection with the output shaft of the drive motor 110. After being decelerated by the reduction gearbox 120, the drive motor 110 can drive the driven screw 130 to rotate along its axis. The driven screw 130 is disposed within the height adjustment base 210. Through slots 211 are respectively formed in two side walls of the height adjustment base 210. The extending direction of the through slots 211 is the same as the extending direction of the driven screw 130. The sliding block 140 is in threaded connection with the driven screw 130, and two ends of the sliding block 140 are respectively disposed within the through slots 211 to form movable ends 141. When the drive motor 110 drives the driven screw 130 to rotate along its axis, the sliding block 140 can move relative to the driven screw 130, and the movable ends 141 can move within the through slots 211.

[0040] In addition, the sliding block 140 is also hinged to the bottom end of the first support rod 221. When the controller controls the driving motor 110 to drive the driven screw 130 to rotate, the sliding block 140 can move on the driven screw 130 to drive the bottom end of the first support rod 221 to approach or move away from the bottom end of the second support rod 222. Specifically, when the user presses the height adjustment button, the controller controls the driving motor 110 to operate. The driving motor 110 drives the driven screw 130 to rotate in the clockwise direction, causing the sliding block 140 to move away from the driving motor 110. The sliding block 140 drives the bottom end of the first support rod 221 to approach the bottom end of the second support rod 222. Thus, the first support rod 221 and the second support rod 222 drive the front axle support unit 300 and the rear axle support unit 400 to rotate simultaneously to lift the chassis of the lawn mower body through the first connecting rod 500 and the second connecting rod 600. When the user presses the lowering button, the controller controls the driving motor 110 to operate. The driving motor 110 drives the driven screw 130 to rotate in the counterclockwise direction, causing the slider to move towards the driving motor 110. The sliding block 140 drives the bottom end of the first support rod 221 to move away from the bottom end of the second support rod 222. Thus, the first support rod 221 and the second support rod 222 drive the front axle support unit 300 and the rear axle support unit 400 to rotate simultaneously to lower the chassis of the lawn mower body through the first connecting rod 500 and the second connecting rod 600.

[0041] In some preferred embodiments, the electric height adjustment device further includes a gear adjustment unit 700. The gear adjustment unit 700 is adapted to obtain the displacement of the sliding block 140 and convert it into an electrical signal for transmission to the controller. The controller is adapted to control the driving motor 110 to operate or stop according to the electrical signal, so that the sliding block 140 moves the same distance relative to the driven screw 130 each time. Furthermore, the first support rod 221 and the second support rod 222 can drive the front axle support unit 300 and the rear axle support unit 400 to rotate a fixed angle through the first connecting rod 500 and the second connecting rod 600, ensuring that the chassis of the lawn mower body is lifted or lowered by the same height each time, and realizing the gear adjustment of the height of the lawn mower chassis.

[0042] Such as Figure 2As shown, in some embodiments, the gear adjustment device includes a magnetic member 710a, an induction plate 730a, and a plurality of Hall sensors 720a. The magnetic member 710a is fixedly installed on the movable end 141 of the slider 140. The induction plate 730a is disposed on the side wall of the height adjustment base 210 and corresponds to the sliding groove 211. Each Hall sensor 720a is uniformly spaced along the extension direction of the sliding groove 211 on the induction plate 730a. Thus, when the slider 140 slides, the magnetic member 710a on the movable end 141 can sequentially pass through each Hall sensor 720a, causing the Hall sensor 720a to detect magnetic fields of different intensities. The Hall sensor 720a is communicatively connected to the controller. The Hall sensor 720a is adapted to detect the magnetic field intensity and convert it into an electrical signal for transmission to the controller. The controller determines whether the magnetic field intensity has reached a preset value based on the electrical signal. If the magnetic field intensity reaches the preset value, the controller controls the drive motor 110 to stop. If the magnetic field intensity does not reach the preset value, the controller controls the drive motor 110 to operate.

[0043] Specifically, when the user presses the adjustment button, the controller controls the drive motor 110 to operate. The drive motor 110 drives the driven screw 130 to rotate so that the slider 140 moves relative to the driven screw 130. The movement of the slider 140 relative to the driven screw 130 enables the movable end 141 to drive the magnetic member 710a to move within the sliding groove 211, causing the magnetic member 710a to be driven to sequentially pass through each Hall sensor 720a. When the movable end 141 drives the magnetic member 710a to move to a position directly opposite the Hall sensor 720a, the magnetic field intensity detected by the Hall sensor 720a is the maximum. The controller determines that the magnetic field intensity has reached the preset value based on the received electrical signal, and the controller controls the drive motor 110 to stop, such that the distance moved by the slider 140 each time is the distance between two Hall sensors 720a, thereby achieving gear adjustment of the front axle support unit 300 and the rear axle support unit 400. Based on the cooperation between the magnetic member 710a and the Hall sensor 720a, electric gear adjustment of the lawn mower chassis height can be achieved. Each time the user presses the adjustment button, the chassis of the lawn mower can be raised or lowered by one gear without manual operation, which is simple and labor-saving.

[0044] As Figures 3-4As shown, in some other embodiments, the gear shifting device includes a switch box 710b, a plurality of micro switches 720b, and a plurality of trigger arms 730b. The switch box 710b is disposed on the side wall of the height adjustment base 210 and corresponds to the sliding groove 211. Each micro switch 720b is uniformly spaced along the extending direction of the sliding groove 211 in the switch box 710b. Each trigger arm 730b is disposed in the switch box 710b corresponding to each micro switch 720b. The bottom end of the trigger arm 730b is hinged to the switch box 710b, and the top end of the trigger arm 730b abuts against the micro switch 720b. The trigger arm 730b can be pressed to close and trigger the micro switch 720b. Each micro switch 720b is communicatively connected to the controller. When the micro switch 720b is closed, the micro switch 720b is adapted to transmit an electrical signal to the controller. The controller receives the electrical signal and controls the driving motor 110 to stop. When the micro switch 720b is open, the micro switch 720b does not transmit an electrical signal to the controller, and the controller does not receive the electrical signal and controls the driving motor 110 to continue to operate.

[0045] Specifically, when the user presses the adjustment button, the controller controls the driving motor 110 to operate. The driving motor 110 drives the driven screw 130 to rotate so that the sliding block 140 moves relative to the driven screw 130. The movement of the sliding block 140 relative to the driven screw 130 enables the movable end 141 to move in the sliding groove 211. The movable end 141 can sequentially pass through each trigger arm 730b and press the trigger arm 730b to close the micro switch 720b. When the movable end 141 moves to a position directly opposite to the trigger arm 730b, the movable end 141 abuts against the trigger arm 730b to close the micro switch 720b. After the micro switch 720b is closed, it transmits an electrical signal to the controller. After receiving the electrical signal, the controller controls the driving motor 110 to stop working, so that the distance that the sliding block 140 moves each time is the distance between two micro switches 720b, thereby realizing the gear adjustment of the front axle support unit 300 and the rear axle support unit 400. When the movable end 141 moves away from the position directly opposite to the trigger arm 730b, the movable end 141 no longer abuts against the trigger arm 730b. The trigger arm 730b is separated from the micro switch 720b under the action of the torsion spring at the bottom end, and the micro switch is opened. Based on the cooperation of the movable end 141, the trigger arm 730b, and the micro switch 720b, the electric gear adjustment of the height of the lawn mower chassis can be realized. Each time the user presses the adjustment button, the chassis of the lawn mower can be raised or lowered by one gear without manual operation, which is simple and labor-saving.

[0046] Further, the front axle support unit 300 specifically includes a front axle connecting member 320 for connecting with the front wheels. A front wheel axle 310 for supporting the lawn mower main body is provided on the front axle connecting member 320, and the first link 500 is hinged to the front axle connecting member 320; the rear axle support unit 400 specifically includes a rear axle connecting member 420 for connecting with the rear wheels. A rear wheel axle 410 for supporting the lawn mower main body is provided on the rear axle connecting member 420, and the second link 600 is hinged to the rear axle connecting member 420. The connection points of the front wheels, the front wheel axle 310 and the first link 500 on the front axle connecting member 320 are arranged in a triangle, and the connection points of the rear wheels, the rear wheel axle 410 and the second link 600 on the rear axle connecting member 420 are also arranged in a triangle. When the height adjustment bracket 220 pulls or pushes the first link 500, the first link 500 can pull or push the front axle connecting member 320 to rotate, so that the front wheel axle 310 is lifted or lowered; when the height adjustment bracket 220 pulls or pushes the second link 600, the second link 600 can pull or push the rear axle connecting member 420 to rotate, so that the rear wheel axle 410 is lifted or lowered, thereby realizing the adjustment of the height of the lawn mower chassis. In addition, both the first link 500 and the second link 600 are connected to the height adjustment bracket 220, and the height adjustment bracket 220 can pull or push the first link 500 and the second link 600 simultaneously, ensuring the synchronization of the height adjustment of the front axle support unit 300 and the rear axle support unit 400.

[0047] On the other hand, the present application also provides a lawn mower, which includes the above-mentioned electric height adjustment device.

[0048] The basic principle, main features and advantages of the present application have been described above. Those skilled in the art of this industry should understand that the present application is not limited by the above-mentioned embodiments. What is described in the above-mentioned embodiments and the specification is only the principle of the present application. Without departing from the spirit and scope of the present application, the present application will have various changes and improvements, and these changes and improvements all fall within the scope of the present application claimed. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. An electric height adjustment device for adjusting the chassis height of a lawn mower, characterized in that: include: Controller; A driving unit, wherein the controller is in communication with the driving unit to control the start and stop of the driving unit; A front axle support unit and a rear axle support unit for supporting a lawn mower; And, a height-adjusting unit, a first connecting rod is hinged between the height-adjusting unit and the front axle supporting unit, a second connecting rod is hinged between the height-adjusting unit and the rear axle supporting unit, the driving unit is drivingly connected to the height-adjusting unit, so that at least a part of the height-adjusting unit can move relative to the driving unit, and then the height-adjusting unit can drive the front axle supporting unit and the rear axle supporting unit to rotate simultaneously through the first connecting rod and the second connecting rod to raise or lower the chassis height of the lawn mower.

2. The electric height adjustment device according to claim 1, characterized in that: The height-adjusting unit includes a height-adjusting base and a height-adjusting bracket, and the height-adjusting bracket includes a first support rod and a second support rod hinged to each other in a V-shaped structure, the bottom end of the first support rod is connected to the driving unit, and the bottom end of the second support rod is connected to the height-adjusting base, the two ends of the first connecting rod are respectively hinged to the second support rod and the front axle support unit, and the two ends of the second connecting rod are respectively hinged to the first support rod and the rear axle support unit, so that the driving unit can drive the bottom end of the first support rod to approach or move away from the bottom end of the second support rod to drive the first connecting rod and the second connecting rod to rotate, so that the front axle support unit and the rear axle support unit rotate at the same time to raise or lower the chassis height of the lawn mower.

3. The electric height adjustment device according to claim 2, characterized in that: The driving unit includes a driving motor, a driven screw and a sliding block. The driven screw is arranged in the height adjustment base and is connected to the output shaft of the driving motor, so that the driving motor can drive the driven screw to rotate along its axis. The sliding block is threadedly connected to the driven screw and is hinged to the bottom end of the first support rod. When the driving motor drives the driven screw to rotate, the sliding block can move relative to the driven screw to drive the bottom end of the first support rod to approach or move away from the bottom end of the second support rod.

4. The electric height adjustment device according to claim 3, characterized in that: A penetrating sliding groove is provided on the side wall of the height adjustment base, and the extension direction of the sliding groove is the same as the extension direction of the driven screw. The end of the sliding block is embedded in the sliding groove to form a movable end, so that when the sliding block moves relative to the driven screw, the movable end moves in the sliding groove.

5. The electric height adjustment device according to claim 4, characterized in that: The electric height adjustment device also includes a gear adjustment unit, which is suitable for obtaining the displacement of the sliding block and converting it into an electrical signal for transmission to the controller. The controller is suitable for controlling the driving unit to work or stop according to the electrical signal, so that the sliding block moves a fixed distance relative to the driven screw each time.

6. The electric height adjustment device according to claim 5, characterized in that: The gear adjustment unit includes a magnetic part, a sensing plate and a plurality of Hall sensors, wherein the magnetic part is fixedly mounted on the movable end, the sensing plate is arranged on the side wall of the height adjustment base and corresponds to the sliding groove, and each of the Hall sensors is arranged on the sensing plate at intervals along the extension direction of the sliding groove, the Hall sensor is communicatively connected with the controller, and the Hall sensor is suitable for sending an electrical signal to the controller when the magnetic field strength reaches a preset value, and the controller controls the drive motor to stop after receiving the electrical signal.

7. The electric height adjustment device according to claim 5, characterized in that: The gear adjustment unit includes a switch box, a plurality of micro switches and a plurality of trigger arms. The switch box is arranged on the side wall of the height adjustment base and corresponds to the sliding groove. The micro switches are arranged in the switch box at intervals along the extension direction of the sliding groove. The trigger arms are arranged in the switch box and correspond to the micro switches. The micro switches are communicatively connected with the controller. The trigger arms are suitable for being pressed by the movable end to trigger the micro switches, so that the micro switches send electrical signals to the controller. After receiving the electrical signals, the controller controls the drive motor to stop.

8. The electric height adjustment device according to any one of claims 2 to 7, characterized in that: The front axle support unit includes a front axle connector for connecting to the front wheel, the front axle connector is provided with a front wheel axle for supporting the lawn mower body, and the first connecting rod is hinged to the front axle connector; the rear axle support unit includes a rear axle connector for connecting to the rear wheel, the rear axle connector is provided with a rear wheel axle for supporting the lawn mower body, and the second connecting rod is hinged to the rear axle connector.

9. The electric height adjustment device according to claim 8, characterized in that: The connection points of the front wheel, the front wheel axle and the first connecting rod on the front axle connecting member are arranged in a triangle; the connection points of the rear wheel, the rear wheel axle and the second connecting rod on the rear axle connecting member are arranged in a triangle.

10. A lawn mower, characterized in that: It comprises an electric height adjustment device as described in any one of claims 1 to 9.

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