Design method of high-speed spiral impeller water pump motor

Abstract

The invention provides a method for designing a high-speed spiral impeller water pump motor, which belongs to the technical field of motor design, and comprises the following steps of: designing a logarithmic spiral impeller structure, integrally designing a logarithmic spiral rotor and a motor object, designing a logarithmic spiral cooling and radiating system, and designing a logarithmic spiral load self-adaptive control mechanism; and finally, designing a low-wear contact interface to finish the design of the water pump motor. Fluid is prolonged by 30% along a spiral line acceleration path, and turbulence loss is reduced by 40%; the hollow structure reduces the weight of the impeller by 25%, reduces the rotational inertia of the rotor by 30%, reduces the rotational inertia of the rotor by 40%, and improves the motor power density by 30%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motivation design, and particularly relates to a high-speed spiral impeller water pump motor design method. BACKGROUND

[0002] The traditional centrifugal pump impeller is mostly of a radial or mixed flow type structure, and relies on the shape and number of blades to achieve fluid pressure increase, but has problems such as low efficiency, easy cavitation, and large vibration and noise at high speed. The spiral impeller (such as axial or mixed flow type) can reduce turbulent loss and improve delivery efficiency through spiral flow channel design, but still faces challenges such as material strength and fluid dynamics optimization when running at high speed. The matching design of the impeller and the motor is insufficient, resulting in a decrease in overall efficiency, such as the mismatch between the motor speed and the optimal working condition of the impeller, and mechanical vibration transmission.

[0003] The motor design relies on empirical formulas and static simulation, and it is difficult to optimize the fluid-structure coupling effect at high speed. High-speed impellers require lightweight high-strength materials (such as titanium alloy and composite materials), but the cost is high and the processing difficulty is great. At the same time, the traditional motor speed regulation mode (such as frequency converter + induction motor) has a slow dynamic response and is difficult to adapt to variable load requirements.

[0004] The traditional high-speed water pump motor generally adopts a separate design of "motor + centrifugal / axial flow impeller", which has the following pain points: efficiency bottleneck: the mechanical transmission loss (such as shaft coupling and gear box) of the high-speed motor and the impeller leads to a system efficiency ≤ 80% (the efficiency of a low-speed pump is about 85%). Low power density: limited by the rotor inertia and heat dissipation capacity, high-power (≥500kW) high-speed pumps are bulky (volume power ratio ≥0.8kW / L). Poor working condition adaptability: when the flow rate / yield is adjusted (such as flow rate fluctuation ±30%), the hydraulic characteristics of the impeller and the torque output of the motor do not match, and surging or overloading easily occurs. Wear and short service life: under high-speed rotation, the gap flow field between the impeller and the pump shell is unstable, and local turbulent flow causes cavitation corrosion, with a maintenance period ≤2000 hours. Therefore, a high-speed spiral impeller water pump motor design method is needed. SUMMARY

[0005] The purpose of the present application is to provide a high-speed spiral impeller water pump motor design method to solve the technical problems mentioned in the background art.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0007] The high-speed spiral impeller water pump motor design method first designs a logarithmic spiral line spiral impeller structure, integrates the logarithmic spiral line rotor and the motor object, designs a logarithmic spiral line cooling and heat dissipation system, designs a logarithmic spiral line load self-adaptive control mechanism, and finally designs a low-wear contact interface to complete the water pump motor design.

[0008] Further, the specific process of designing the logarithmic spiral impeller structure is as follows: double-head logarithmic spiral blades are adopted, the pitch P=2πr0 / n, r0 is the base circle radius, n is the number of heads, the blade outlet angle β2 is consistent with the tangential velocity direction of the motor rotor, the fluid separation loss is reduced, the pitch is dynamically adjusted according to the flow requirement, stepless speed regulation is realized through motor frequency conversion control, micro-channels are arranged along the spiral line inside the blade for cooling medium flow, and the radial thermal expansion deformation of the impeller is reduced.

[0009] Further, in the double-head logarithmic spiral blade, the logarithmic spiral blade profile equation is designed first: r(θ)=r0e θcotα , r0 is the base circle radius, that is, the minimum radius of the impeller inlet, α is the spiral angle, which determines the blade unwinding rate, θ is the rotation angle, in the double-head spiral, the pitch P=2πr0 / n, n is a positive integer, which ensures the symmetry of the flow passage and reduces the radial force fluctuation, the spiral angle is dynamically matched, the outlet angle β2=arctan(v 转子切线 / v 流体轴向 ), when the impeller rotates at high speed, the fluid separation loss is reduced by matching β2 with the tangential velocity direction of the rotor.

[0010] Further, in the dynamic adjustment of the pitch according to the flow requirement, the pitch is adjusted in real time through motor frequency conversion control, the adjustment ratio is ≥5:1, different flow requirements are adapted, and the adjustment mode includes mechanical adjustment of the deformable blade skeleton and pneumatic / hydraulic drive blade angle fine adjustment.

[0011] Further, the specific process of the integrated design of the logarithmic spiral rotor and the motor object is as follows: the spiral impeller and the motor rotor are designed to be coaxial and integrated, a hollow logarithmic spiral rotor core is designed, the core adopts 0.2mm-thick high-permeability silicon steel sheets, which are stacked into a spiral line profile, flat copper wire windings are embedded in the slots, the slot fullness rate is ≥85%, a permanent magnet embedded structure is designed, rare earth surface-mounted permanent magnets are embedded at the bottom of the spiral slot of the rotor core, the air gap magnetic density uniformity is optimized through spiral line distribution, the fluctuation is ≤5%, a flexible connection interface is designed, the torque is transmitted through the logarithmic spiral interference fit between the rotor and the spiral impeller, the traditional key connection is replaced, and stress concentration is eliminated.

[0012] Further, the specific process of designing the logarithmic spiral cooling and heat dissipation system is as follows: a spiral cooling channel is designed, which is deeply coupled with the geometric characteristics of the logarithmic spiral, in the stator spiral cooling groove, a spiral groove with a depth of 1-2mm and a width of 2-3mm is arranged on the outer circle of the stator core, deionized water or fluorinated liquid flows along the spiral line, the path length and the heat dissipation area are proportional to r 2Regular expansion, matching motor radial heat distribution, design rotor spiral guide hole, rotor core along the axial direction is provided with spiral guide hole, diameter 4-6mm, is communicated with stator cooling groove, forms the two-way circulation cooling path of stator to rotor, in intelligent temperature control strategy, through the real-time monitoring of buried temperature sensor winding, core temperature, combined with PID controller dynamic adjustment cooling pump flow, ensure that the winding hot spot temperature is less than or equal to 100 DEG C.

[0013] Further, the specific process of designing the logarithmic spiral line load adaptive control mechanism is: constructing several physical field coupling intelligent control methods, first, several field coupling modeling, establishing motor and pump joint simulation model, including electromagnetic field, fluid mechanics and heat conduction, input logarithmic spiral line geometric parameters, output torque and speed characteristic curve, then actual working condition identification and prediction, through real-time acquisition motor current, pump outlet pressure, flow signal, combined with LSTM neural network to predict the load change trend in the future 5-10 seconds, finally, adaptive adjustment control, based on the prediction result, dynamically adjust the motor pole number or frequency conversion frequency, combined with the uniform expansion of logarithmic spiral line, so that the impeller hydraulic efficiency always works in the peak area.

[0014] Further, the specific process of low wear contact interface design is: adopting logarithmic spiral line sealing and gap compensation structure, designing spiral surface mechanical seal, logarithmic spiral line type mechanical seal is adopted between pump body and rotor, the sealing surface profile is matched with the spiral line of the rotor, the contact stress is uniformly distributed along the axial direction, the maximum contact stress is reduced by 40%, the DLC coating is used to realize zero leakage, and the dynamic gap compensation mode is used, the thermal expansion amount is monitored through the temperature sensor, the radial fine adjustment mechanism of the spiral sealing surface is driven to compensate the gap change caused by temperature rise.

[0015] Further, when designing the water pump motor, the geometric shape of the logarithmic spiral line needs to provide smooth speed change and torque transmission, the logarithmic spiral line has the characteristics of uniform expansion, which can better adapt to the load change under different working conditions, so that the motor can maintain good performance in the working range, by adopting the design of the logarithmic spiral line, the direct contact between the internal components of the motor is reduced to a certain extent, and then the wear rate is reduced, and the service life of the equipment is prolonged.

[0016] Further, when designing the water pump motor, the two opposite blades of the spiral drive wheel of the driving mechanism, the spiral drive wheel has large contact area with the ground and is hollow inside, and the weight is light, the ground pressure is less than the set value, at the same time, the spiral blade can cut soft ground, obtain the propelling force greater than the set value, the adaptability to soft ground is better, the performance is stronger, and the problems of easy sinking, easy overturning and easy skidding of the existing traveling machinery can be overcome by taking advantage of the advantages of the spiral drive wheel.

[0017] The application has the following beneficial effects due to the adoption of the above technical scheme:

[0018] The fluid of the present application is extended by 30% along the helical line acceleration path, and the turbulent flow loss is reduced by 40%; the hollow structure reduces the weight of the impeller by 25%, the rotor moment of inertia is reduced by 30%, the rotor moment of inertia is reduced by 40%, the motor power density is increased by 30%(≥5kW / kg); the integrated structure reduces the transmission link, the system efficiency is increased to 92%, the heat dissipation efficiency is increased by 50%, the maximum allowable speed of the motor is increased from 8000rpm to 15000rpm, the insulation life is extended by 2 times, the system efficiency fluctuation under wide load is ≤3%(the traditional pump fluctuation is ≥10%), and the system is suitable for complex working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a flow chart of the method of the present application;

[0020] Figure 2 is a magnetic density distribution diagram of the motor of the present application;

[0021] Figure 3 is a temperature distribution diagram of the motor of the present application;

[0022] Figure 4 is a torque curve diagram of the motor of the present application;

[0023] Figure 5 is an axial and radial helical turbine stress analysis diagram of the present application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present application more clear and explicit, the following preferred embodiments are given with reference to the drawings, and the present application is further described in detail. However, it should be pointed out that many details in the description are only for the reader to have a thorough understanding of one or more aspects of the present application, and the aspects of the present application can be realized without these specific details.

[0025] As shown in Figures 1-5 , the design method of high-speed helical impeller water pump motor is to design the logarithmic spiral helical impeller structure first, to design the logarithmic spiral rotor and motor object integration, to design the logarithmic spiral cooling and heat dissipation system, to design the logarithmic spiral load adaptive control mechanism, and finally to design the low wear contact interface, and to complete the design of water pump motor.

[0026] In the embodiment of the present application, the specific process of designing the logarithmic spiral impeller structure is as follows: a double-head logarithmic spiral blade is adopted, the pitch P=2πr0 / n, r0 is the base circle radius, n is the number of heads, the blade outlet angle β2 is consistent with the tangential velocity direction of the motor rotor, the fluid separation loss is reduced, the pitch is dynamically adjusted according to the flow requirement, stepless speed regulation is realized through motor frequency conversion control, micro-channels are arranged in the blade along the spiral line for cooling medium flow, and the radial thermal expansion deformation of the impeller is reduced. The equiangularity and uniform expansion of the logarithmic spiral are applied to the high-speed motor-pump integrated design, and the radial radiation limitation of the traditional impeller is broken through.

[0027] Rotor / impeller: high-strength aluminum alloy (such as 7075-T6, density 2.8 g / cm 3 , tensile strength ≥ 570 MPa) or carbon fiber reinforced composite material. The stator core adopts 0.2 mm thick high-permeability low-loss silicon steel sheet, the sealing element adopts DLC coating with a thickness of 5-10 μm.

[0028] In the double-head logarithmic spiral blade, the logarithmic spiral blade profile equation is designed first: r(θ)=r0e θcotα , r0 is the base circle radius, that is, the minimum radius of the impeller inlet, α is the spiral angle, which determines the blade expansion rate, θ is the rotation angle, in the double-head spiral, the pitch P=2πr0 / n, n is a positive integer, which ensures the symmetry of the flow passage and reduces the radial force fluctuation, the spiral angle is dynamically matched, the outlet angle β2=arctan(v 转子切线 / v 流体轴向 ), when the impeller rotates at high speed, the fluid separation loss is reduced by matching β2 with the tangential velocity direction of the rotor. In the dynamic adjustment of the pitch according to the flow requirement, the pitch is adjusted adaptively through motor frequency conversion control, the adjustment ratio is ≥ 5:1, different flow requirements are adapted, and the adjustment mode includes mechanical adjustment of the deformable blade skeleton and pneumatic / hydraulic driven blade angle fine adjustment.

[0029] In the embodiment of the present application, the specific process of the logarithmic spiral rotor and the motor object integrated design is as follows: the spiral impeller and the motor rotor are coaxially integrated manufactured, the hollow logarithmic spiral rotor core is designed, the core adopts 0.2 mm thick high-permeability silicon steel sheet, which is stacked into a spiral line profile, the flat copper wire winding is embedded in the slot, the slot fullness rate is ≥ 85%,

[0030] A permanent magnet embedded structure is designed, a surface-mounted rare earth permanent magnet is embedded in the bottom of the spiral slot of the rotor core, the air gap magnetic density uniformity is optimized through spiral line distribution, the fluctuation is ≤ 5%, a flexible connection interface is designed, the torque is transmitted through the logarithmic spiral interference fit between the rotor and the spiral impeller, the traditional key connection is replaced, and stress concentration is eliminated.

[0031] In the embodiment of the present application, the specific process of designing the logarithmic spiral cooling and heat dissipation system is as follows: a spiral cooling channel is designed, which is deeply coupled with the geometric characteristics of the logarithmic spiral. In the stator spiral cooling groove, a spiral groove is opened on the outer circle of the stator core, with a depth of 1-2 mm and a width of 2-3 mm. Deionized water or fluorinated liquid flows along the spiral line, and the path length and heat dissipation area are expanded according to the r 2 law, matching the radial heat distribution of the motor. The rotor spiral guide hole is designed, and the spiral guide hole with a diameter of 4-6 mm is opened on the rotor core along the axial direction and is connected with the stator cooling groove to form a bidirectional circulation cooling path from the stator to the rotor. In the intelligent temperature control strategy, the winding and core temperatures are monitored in real time by the embedded temperature sensor, and the cooling pump flow is dynamically adjusted by the PID controller to ensure that the winding hot spot temperature is ≤100℃.

[0032] In the embodiment of the present application, the specific process of designing the logarithmic spiral load adaptive control mechanism is as follows: a plurality of physical field coupling intelligent control methods are constructed. First, a plurality of field coupling modeling is performed, a motor and pump joint simulation model is established, which includes electromagnetic field, fluid mechanics and heat conduction, the logarithmic spiral geometric parameters are input, and the torque and speed characteristic curve is output. Then, actual working condition recognition and prediction are performed, the motor current, pump outlet pressure and flow signals are collected in real time, the future 5-10 seconds of load change trend is predicted by combining the LSTM neural network, and finally adaptive adjustment control is performed based on the prediction result. The motor pole number or variable frequency frequency is dynamically adjusted, and the uniform expansion of the logarithmic spiral line is combined to make the impeller hydraulic efficiency always work in the peak value area.

[0033] In the embodiment of the present application, the specific process of designing the low-wear contact interface is as follows: a logarithmic spiral line sealing and gap compensation structure is adopted, a spiral surface mechanical seal is designed, and a logarithmic spiral line type mechanical seal is adopted between the pump body and the rotor. The sealing surface profile matches the rotor spiral line, the contact stress is uniformly distributed along the axial direction, the maximum contact stress is reduced by 40%, a DLC coating is used to realize zero leakage, a dynamic gap compensation method is used, the thermal expansion amount is monitored by a temperature sensor, a radial fine adjustment mechanism of the spiral sealing surface is driven to compensate for the gap change caused by temperature rise.

[0034] The combination of the high-power high-speed motor designed by the method and the logarithmic spiral line can exhibit unique advantages in specific application scenarios. When it is applied to motor design, the main advantages include:

[0035] 1. Smooth transition: The geometric shape of the logarithmic spiral line can provide smooth speed change and torque transmission, which is particularly important for applications that require smooth acceleration or deceleration.

[0036] 2. Strong adaptability: due to the uniform expansion characteristics of the logarithmic spiral, it can better adapt to the load changes under different working conditions, so that the motor can maintain good performance in a wider working range.

[0037] 3. Reduce wear and tear: by adopting the design of logarithmic spiral, the direct contact between the internal components of the motor can be reduced to a certain extent, thereby reducing the wear rate and prolonging the service life of the equipment.

[0038] In high-performance compressor products, the motor of the product developed in this project is matched with an ultra-high temperature heating scroll compressor. For high-temperature heating applications and environmentally friendly refrigerant characteristics, through high-load, high-pressure ratio design, multiple flexible design and other new and unique designs, higher condensing temperature and higher reliability are achieved, with a 28% increase in compression efficiency and a more than 10% reduction in volume.

[0039] In high-power hydraulic motor pump products, the motor of the product in this project provides a high-speed, high-reliability, high-pressure, long-life motor pump device. The internal gear pump is built into the motor rotor and packaged in the same housing. This scheme has high integration, while reducing the overall noise by more than 10%, improving the operating efficiency by 25%, and increasing the power density by 20%.

[0040] In the field of spiral drive robots, the two opposite blade rotation direction spiral drive wheels of the drive mechanism developed in this project have a large contact area with the ground and are hollow inside, which reduces the weight and ground pressure. At the same time, the spiral blades can cut soft ground and generate a larger propulsion force, making the device more adaptable to soft ground and more powerful. By taking advantage of the characteristics of the spiral drive wheel, the existing problems of easy sinking, easy overturning and easy skidding of existing travel machines can be overcome, with a 36% increase in travel speed and a more than 20% increase in system efficiency.

[0041] Multi-physical field coupling model and adaptive control algorithm support wide operating conditions, meeting complex industrial needs. The motor designed by this method promotes the development of water pumps, compressors and other devices towards high efficiency, intelligence and long life.

[0042] The remaining matters of the present application are known technologies.

[0043] The above description is only the preferred embodiment of the present application, and it should be noted that for ordinary skilled persons in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered within the scope of protection of the present application.

Claims

1. Design method of high-speed spiral impeller water pump motor, characterized by: First, the logarithmic spiral impeller structure is designed, the logarithmic spiral rotor and motor body are integrated, the logarithmic spiral cooling and heat dissipation system is designed, the logarithmic spiral load adaptive control mechanism is designed, and finally the low-wear contact interface is designed to complete the water pump motor design.

2. The method for designing a high-speed spiral impeller water pump motor according to claim 1, characterized in that: The specific process of designing the logarithmic spiral impeller structure is as follows: using double-headed logarithmic spiral blades, the pitch P = 2πr0 / n, r0 is the base circle radius, n is the number of heads, the blade outlet angle β2 is consistent with the direction of the motor rotor tangential speed, reducing fluid separation loss, dynamically adjusting the pitch according to flow demand, and realizing stepless speed regulation through motor frequency conversion control. Microchannels are opened along the spiral line inside the blade for the flow of cooling medium to reduce radial thermal expansion deformation of the impeller.

3. The method for designing a high-speed spiral impeller water pump motor according to claim 2, characterized in that: In the double-ended logarithmic spiral blade, first design the logarithmic spiral blade profile equation: r(θ)=r0e θcotα , r0 is the base circle radius, that is, the minimum radius of the impeller inlet, α is the helix angle, which determines the blade expansion rate, θ is the rotation angle, in the double-headed helix, the pitch P=2πr0 / n, n is a positive integer, to ensure the symmetry of the flow channel, reduce the radial force fluctuation, the helix angle is dynamically matched, and the outlet angle β2=arctan(v 转子切线 / v 流体轴向 ), when the impeller rotates at high speed, the fluid separation loss is reduced by matching β2 with the direction of the rotor tangential speed.

4. The method for designing a high-speed spiral impeller water pump motor according to claim 2, characterized in that: The pitch is dynamically adjusted according to the flow demand, and the variable pitch is adaptively adjusted. The pitch is adjusted in real time through motor frequency control. The adjustment ratio is ≥5:1 to adapt to different flow demands. The adjustment methods include mechanical adjustment of the deformable blade skeleton and pneumatic / hydraulic drive blade angle fine-tuning.

5. The method for designing a high-speed spiral impeller water pump motor according to claim 1, characterized in that: The specific process of the integrated design of the logarithmic spiral rotor and the motor object is as follows: design the coaxial integrated manufacturing of the spiral impeller and the motor rotor, design the hollow logarithmic spiral rotor core, the core uses 0.2mm thick high magnetic permeability silicon steel sheets, stacked into a spiral profile, and flat copper wire windings are embedded in the slots, with a slot fill rate of ≥85%, design a permanent magnet embedded structure, embed surface-mounted rare earth permanent magnets at the bottom of the spiral slots of the rotor core, optimize the air gap magnetic flux uniformity through spiral distribution, and achieve fluctuations of ≤5%, design a flexible connection interface, and achieve torque transmission between the rotor and the spiral impeller through logarithmic spiral interference fit, replacing traditional key connections and eliminating stress concentration.

6. The method for designing a high-speed spiral impeller water pump motor according to claim 1, characterized in that: The specific process of designing the logarithmic spiral cooling and heat dissipation system is as follows: design a spiral cooling channel, deeply coupled with the geometric characteristics of the logarithmic spiral, in the stator spiral cooling groove, a spiral groove is opened on the outer circle of the stator core, with a depth of 1 to 2 mm and a width of 2 to 3 mm. The cooling medium is deionized water or fluorinated liquid flowing along the spiral line. The path length and heat dissipation area are calculated according to r 2 The regular expansion is carried out to match the radial heat distribution of the motor. The rotor spiral guide holes are designed. The rotor core is provided with spiral guide holes along the axial direction with a diameter of 4 to 6 mm, which are connected to the stator cooling groove to form a bidirectional circulation cooling path from the stator to the rotor. In the intelligent temperature control strategy, the winding and core temperatures are monitored in real time through embedded temperature sensors, and the cooling pump flow is dynamically adjusted in combination with the PID controller to ensure that the hot spot temperature of the winding is ≤100°C.

7. The method for designing a high-speed spiral impeller water pump motor according to claim 1, characterized in that: The specific process of designing the logarithmic spiral load adaptive control mechanism is as follows: constructing several physical field coupling intelligent control methods, firstly, modeling several field couplings, establishing a joint simulation model of the motor and pump, including electromagnetic fields, fluid mechanics and heat conduction, inputting the logarithmic spiral geometric parameters, and outputting the torque and speed characteristic curves, then identifying and predicting the actual working conditions, through real-time collection of motor current, pump outlet pressure, and flow signals, combined with the LSTM neural network to predict the load change trend within the next 5 to 10 seconds, and finally adaptively adjusting the control. Based on the prediction results, the number of motor poles or the frequency conversion frequency are dynamically adjusted, and combined with the uniform scalability of the logarithmic spiral, the impeller hydraulic efficiency is always working in the peak area.

8. The method for designing a high-speed spiral impeller water pump motor according to claim 1, characterized in that: The specific process of low-wear contact interface design is as follows: adopting logarithmic spiral sealing and gap compensation structure, designing spiral surface mechanical seals, using logarithmic spiral mechanical seals between the pump body and the rotor, the sealing surface profile matches the rotor spiral, the contact stress is evenly distributed along the axial direction, the maximum contact stress is reduced by 40%, and with the DLC coating, zero leakage is achieved. Using dynamic gap compensation, the thermal expansion is monitored by a temperature sensor, and the radial fine-tuning mechanism of the spiral sealing surface is driven to compensate for the gap changes caused by temperature rise.

9. The method for designing a high-speed spiral impeller water pump motor according to claim 1, characterized in that: When designing a water pump motor, the geometry of the logarithmic spiral needs to provide smooth speed changes and torque transmission. The logarithmic spiral has the characteristic of uniform expansion, which can better adapt to load changes under different working conditions, allowing the motor to maintain good performance within the working range. By adopting the logarithmic spiral design, the direct contact between the internal components of the motor can be reduced to a certain extent, thereby reducing the wear rate and extending the service life of the equipment.

10. The method for designing a high-speed spiral impeller water pump motor according to claim 1, characterized in that: When designing the water pump motor, the driving mechanism has two spiral drive wheels with opposite blade rotation directions. The spiral drive wheels have a large contact area with the ground and are hollow inside, light in weight, and have a ground pressure less than the set value. At the same time, the spiral blades can cut the soft ground to obtain a propulsion force greater than the set value. It has better adaptability to soft roads and stronger passing performance. The advantages of the spiral drive wheel may overcome the problems of existing traveling machinery being prone to sinking, overturning, and slipping.

Images