Mower motor mechanical characteristic design method

Abstract

The invention discloses a mowing machine motor mechanical characteristic design method, which comprises the following steps: acquiring data of a mowing machine related to two different motion working conditions of flat ground and climbing to reversely deduce motor rotating speed values under the two working conditions; in the simulation software, initial parameters related to the mower motor are input, a mower motor mathematical model is established, and a mower motor efficiency curve is output; the highest point on the efficiency curve of the mower motor is used as an anchor point, and the position of the highest point of the efficiency curve of the motor is moved back and forth by adjusting the number of turns of a motor coil, so that the efficiency values of the designed rotating speeds of the motor in two required working conditions are on the same level; a2, the rotating speed of the highest efficiency point in the efficiency curve serves as an anchor point, the rotating speed of the highest point of the efficiency curve is set between the ground operation rotating speed and the climbing operation rotating speed by designing the counter electromotive force value of the motor, and the motor efficiency of the two different operation conditions is similar. And the efficiency balance of the motor under two different working conditions is effectively realized, and the cruising ability of the mower is improved.

Description

Technical Field

[0001] The invention relates to a lawn mower motor, and in particular to a method for designing mechanical characteristics of a lawn mower motor used in a lawn mower motor having a rotor structure of a surface-mounted permanent magnet brushless motor. Background Art

[0002] With the development of intelligent equipment, lawn mowers are also widely used to improve mowing efficiency and reduce labor intensity, playing a vital role in weed trimming and garden mowing. They are also being promoted and applied in more and more urban greening, agricultural garden construction, and weed or lawn trimming tasks growing in ridges, mountains and forests. Although lawn mowers have greatly reduced labor intensity and improved mowing efficiency, there is still an actual operating condition of lawn mowers: when performing mowing tasks, lawn mowers will face two different motor efficiencies in flat ground and climbing conditions; in flat ground conditions, the motor is in a high-speed and low-torque state, while in climbing conditions, the motor is in a low-speed and high-torque state; conventional motors are more efficient at low speeds and less efficient at high speeds. How to effectively achieve a balance in motor efficiency under two different conditions and improve the endurance of lawn mowers is an important technical issue worthy of in-depth research and improvement. Summary of the invention

[0003] The present invention aims to solve the problem that the existing lawn mowers have different motor efficiencies in two different motion conditions, namely, flat ground and climbing, when performing mowing tasks, which is not conducive to improving the endurance of the lawn mower. The present invention provides a lawn mower motor mechanical characteristic design method that can effectively achieve motor efficiency balance in two different working conditions and improve the endurance of the lawn mower.

[0004] In order to solve the above technical problems, the present invention adopts a method for designing the mechanical characteristics of a lawn mower motor, including the following design adjustment method: A1. By collecting data related to the lawn mower's two different motion conditions, namely, flat ground and climbing, the motor speed values ​​under these two conditions can be inferred. A2. Input the initial parameters related to the lawn mower motor in the simulation software, establish the mathematical model of the lawn mower motor, and output the efficiency curve of the lawn mower motor; A3. Take the highest point on the efficiency curve of the lawn mower motor in step A2 as the anchor point, and adjust the number of turns of the motor coil to move the position of the highest point of the motor efficiency curve forward and backward so that the efficiency values ​​of the motor design speeds under the two required working conditions are at the same level; A4. Taking the speed of the highest efficiency point in the efficiency curve in step A2 as the anchor point, by designing the back EMF value of the motor, the speed of the highest point of the efficiency curve is set between the speeds of ground operation and climbing operation, so as to achieve the same or similar motor efficiency in these two different operating conditions.

[0005] The motor efficiency of these two working conditions can be similar, which greatly reduces the current of the lawn mower when climbing a slope. It can effectively achieve a balance in the motor efficiency of the two different working conditions and improve the endurance of the lawn mower. Preferably, in the above step A1, the data related to the two different motion conditions of flat ground and climbing include the driving speed data of the lawn mower in the two different motion conditions of flat ground and climbing and the wheel size data of the lawn mower, so as to improve the data collection effectiveness of the lawn mower in the two different motion conditions of flat ground and climbing.

[0006] Preferably, in the above step A2, the initial parameters related to the lawn mower motor include the stator and rotor structure size, the number of coil turns and the magnetic steel parameters of the lawn mower motor, thereby improving the collection effectiveness of the initial parameters related to the lawn mower motor.

[0007] Preferably, in the above steps A2 to A4, the efficiency curve is based on ANSYS simulation software, so as to improve the efficiency curve simulation and obtain simple effectiveness.

[0008] The beneficial effects of the present invention are: the motor efficiency in the two working conditions can be similar, the current of the lawn mower when climbing a slope can be greatly reduced, the motor efficiency balance in the two different working conditions can be effectively achieved, and the endurance of the lawn mower can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0010] Figure 1 It is a schematic diagram of a page for setting the number of turns of a motor coil of a simulation software in the method for designing the mechanical characteristics of a lawn mower motor of the present invention.

[0011] Figure 2 It is a schematic diagram of the efficiency curve of the lawn mower motor in the mechanical characteristic design method of the lawn mower motor of the present invention.

[0012] Figure 3 It is a schematic diagram of establishing a mathematical model of a motor in the method for designing the mechanical characteristics of a lawn mower motor of the present invention. DETAILED DESCRIPTION

[0013] Figure 1 , Figure 2 , Figure 3 In the embodiment shown, a method for designing mechanical characteristics of a lawn mower motor includes the following design adjustment method: A1. By collecting data related to the lawn mower's two different motion conditions, namely, flat ground and climbing, the motor speed values ​​under these two conditions can be inferred. A2. Input the initial parameters related to the lawn mower motor in the simulation software, establish the mathematical model of the lawn mower motor, and output the efficiency curve of the lawn mower motor; A3. Take the highest point on the efficiency curve of the lawn mower motor in step A2 as the anchor point, and adjust the number of turns of the motor coil to move the position of the highest point of the motor efficiency curve forward and backward so that the efficiency values ​​of the motor design speeds under the two required working conditions are at the same level; A4. Take the speed of the highest efficiency point in the efficiency curve in step A2 as the anchor point, and set the speed of the highest point of the efficiency curve between the ground running and the climbing running speed by designing the back electromotive force value of the motor, so that the motor efficiency of these two different operating conditions is the same or similar. When similar, the motor efficiency under the two different operating conditions differs by 15%.

[0014] In the above step A1, the data related to the two different motion conditions of flat ground and climbing include the driving speed data of the lawn mower in the two different motion conditions of flat ground and climbing and the wheel size data of the lawn mower.

[0015] In the above step A2, the initial parameters related to the lawn mower motor include the stator and rotor structure size, coil turns and magnetic steel parameters of the lawn mower motor. In the above steps A2 to A4, the efficiency curve is based on the ansys simulation software.

[0016] Based on the efficiency curve of ANSYS simulation software, the speed of the highest efficiency point in the efficiency curve is used as the anchor point. By designing the back-EMF value of the motor, the speed of the highest point of the efficiency curve is set between the ground running and climbing running speeds. This can achieve similar motor efficiency in these two working conditions, greatly reduce the current of the lawn mower when climbing, and improve the endurance of the lawn mower.

[0017] First, we need to infer the motor speed values ​​under the two working conditions of the lawn mower, namely, the driving speed on flat ground and the wheel hub size. Then, in the simulation software, input the initial parameters related to the motor, including the stator and rotor structure size, the number of coil turns, the magnetic steel parameters, etc., establish the motor mathematical model, and output the motor efficiency curve; take the highest point on the efficiency curve as the anchor point, and adjust the number of motor coil turns to move the position of the highest point of the motor efficiency curve back and forth, so that the efficiency values ​​of the motor design speeds under the two working conditions we need are at the same level, so that the motor can maintain the same motor output efficiency under the two working conditions.

[0018] When in use, for example, the climbing speed of the lawn mower motor is 2500RPM, and the flat ground speed is 3900RPM. The simulation software establishes a mathematical model and outputs the motor efficiency curve. By observing the efficiency curve, the motor turns value is adjusted so that when the highest point of the motor's efficiency curve is at 3400RPM, the motor's output efficiency is at the same level when it is at 2500RPM and 3900RPM.

[0019] The above content and structure describe the basic principle, main features and advantages of the product of the present invention, which should be understood by those skilled in the art. The above examples and descriptions are only for explaining the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which are within the scope of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for designing mechanical characteristics of a lawn mower motor, characterized in that The following design adjustment methods are included: A1. By collecting data related to the lawn mower's two different motion conditions, namely, flat ground and climbing, the motor speed values ​​under these two conditions can be inferred. A2. Input the initial parameters related to the lawn mower motor in the simulation software, establish the mathematical model of the lawn mower motor, and output the efficiency curve of the lawn mower motor; A3. Take the highest point on the efficiency curve of the lawn mower motor in step A2 as the anchor point, and adjust the number of turns of the motor coil to move the position of the highest point of the motor efficiency curve forward and backward so that the efficiency values ​​of the motor design speeds under the two required working conditions are at the same level; A4. Taking the speed of the highest efficiency point in the efficiency curve in step A2 as the anchor point, by designing the back EMF value of the motor, the speed of the highest point of the efficiency curve is set between the speeds of ground operation and climbing operation, so as to achieve the same or similar motor efficiency in these two different operating conditions.

2. The method for designing mechanical characteristics of a lawn mower motor according to claim 1, characterized in that: In the above step A1, the data related to the two different motion conditions of flat ground and climbing include the driving speed data of the lawn mower in the two different motion conditions of flat ground and climbing and the wheel size data of the lawn mower.

3. The method for designing mechanical characteristics of a lawn mower motor according to claim 1, characterized in that: In the above step A2, the initial parameters related to the lawn mower motor include the stator and rotor structure dimensions, the number of coil turns and the magnetic steel parameters of the lawn mower motor.

4. The method for designing mechanical characteristics of a lawn mower motor according to claim 1, characterized in that: The above steps A2 to A4 are efficiency curves based on ANSYS simulation software.

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