Self-energy supply magneto-rheological damper of hub motor driven electric automobile
Technical Field
The invention relates to the technical field of vehicle system vibration reduction, in particular to a self-powered magnetorheological vibration damper of an electric automobile driven by a hub motor.
Background
Until now, automobiles have become essential vehicles for people to go out and goods to transport. However, the conventional internal combustion engine automobile also brings about problems of high energy consumption, emission amplification, energy shortage and environmental deterioration. Compared with the traditional automobile, the electric automobile is rapidly developed due to the advantages of low noise, low emission, high energy utilization rate and the like. The hub motor driven electric automobile cancels a complex power traditional system, directly drives at the wheel, has the advantages of high transmission efficiency, small occupied space, simple control and the like, and is an important direction for the development of future electric automobiles. However, the structural features of the in-wheel motor driven electric vehicle also cause a number of vehicle dynamics problems. The unsprung mass of the vehicle is increased by adopting the hub motor, and certain negative effects are generated on the vertical vibration dynamic performance of the vehicle, including vehicle body acceleration and tire dynamic load, particularly the vibration of the wheel is aggravated. Meanwhile, the short endurance mileage is another important difficulty in the development of the electric automobile.
Aiming at the problems of the vertical dynamic negative effect and the energy consumption of the hub motor driven electric automobile, a controllable active electromagnetic suspension is introduced into a vehicle vibration reduction system by many scholars. At present, a linear motor type electromagnetic suspension becomes a research hotspot. The linear motor type electromagnetic actuator can realize active control and energy recovery by directly realizing the relative linear motion of the primary and the magnetic poles without an additional transmission mechanism. However, the linear motor electromagnetic suspension system can adjust the electromagnetic thrust of the motor in real time and recover energy under a specific driving condition. However, the problems still exist, namely, although the riding comfort of the vehicle or the wheel grounding performance can be optimized by adjusting the damping force of the shock absorber, the performance is essentially a compromise, and the optimization cannot be carried out on the vehicle and the wheel; secondly, the active electromagnetic suspension is adopted, a large amount of energy is consumed to meet the electromagnetic thrust required by ideal vehicle performance, and the energy recovered by the electromagnetic suspension under a specific working condition is very limited, so that the energy consumption is higher.
On the other hand, as electromagnetic materials are continuously developed, dynamic vibration absorbers are also rapidly developed. The traditional passive dynamic vibration absorber is taken as a subsystem and attached to a main system, and the energy distribution and the transfer characteristic of the main system are changed by utilizing the principle of anti-resonance, so that the vibration of the main system is inhibited. In recent years, active electromagnetic dynamic vibration absorbers are widely used, and electromagnetic actuators adopted by the active electromagnetic dynamic vibration absorbers are designed according to the working principle of a linear motor. The stiffness of the electromagnetic spring can be changed by changing the current led into the coil, so that the natural frequency of the vibration absorber is changed. Therefore, if the active electromagnetic dynamic vibration absorber is applied to the in-wheel motor driven electric vehicle to suppress the vibration of the wheel, it is beneficial to improve the wheel grounding performance. Although the natural frequency of the active electromagnetic dynamic vibration absorber can be changed, the problems of complex control and high energy consumption exist.
In summary, the hub motor driven electric automobile has the problems of poor riding comfort and poor driving safety due to the negative effect of vertical dynamic performance, and the active electromagnetic suspension or the active electromagnetic dynamic vibration absorber is adopted, so that the control is complex and the energy consumption is large.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides the self-powered magnetorheological damper for the hub motor driven electric automobile, so as to meet the development requirements of 'comfort, safety and energy conservation' of the hub motor driven electric automobile.
The present invention achieves the above-described object by the following technical means.
A wheel hub motor driven electric automobile self-energized magnetorheological damper comprises a magnetorheological damper and a linear electromagnetic power vibration absorber, wherein the linear electromagnetic power vibration absorber is rigidly connected with an outer cylinder of the magnetorheological damper; the linear electromagnetic dynamic vibration absorber comprises a stator and a rotor; the stator comprises a central rod and permanent magnets, and the permanent magnets are stacked on the periphery of the central rod; the rotor comprises a coil winding, a winding iron core and an outer shell, the end part of the outer shell is in clearance fit with the stator through a sliding bearing, the winding iron core is fixedly connected inside the outer shell, and the coil winding is wound on the winding iron core; the upper end and the lower end of the outer shell are fixed through annular elastic materials.
According to the further technical scheme, the center rod is a magnetorheological damper outer cylinder, a cylindrical shell B is arranged outside the magnetorheological damper outer cylinder, and the upper end and the lower end of the shell are fixedly connected with the cylindrical shell B through annular elastic materials.
According to the further technical scheme, the central rod is fixed inside the cylindrical shell A, the cylindrical shell A is rigidly connected to the lower portion of the outer cylinder of the magnetorheological damper, and the upper end and the lower end of the outer shell are fixedly connected with the cylindrical shell A through annular elastic materials.
According to the further technical scheme, the central rod is fixed inside the C-shaped connector, the C-shaped connector is rigidly connected with the outer cylinder of the magneto-rheological damper, and the upper end and the lower end of the outer shell are fixedly connected with the C-shaped connector through annular elastic materials.
According to a further technical scheme, the upper end of the shell of the magneto-rheological shock absorber is connected with a vehicle body through an upper connecting piece, and the lower end of the shell of the magneto-rheological shock absorber is connected with a wheel half shaft through a lower lifting lug; the upper part of the magneto-rheological shock absorber shell is fixed with a spring tray, and a spiral spring is arranged between the spring tray and the upper connecting piece.
According to a further technical scheme, the permanent magnets and the iron cores are stacked on the periphery of the central rod in an alternating pair mode.
In a further technical scheme, the center rod is an aluminum center rod.
According to a further technical scheme, the annular elastic material is a non-metal rubber spring, and the outer shell is made of an iron material.
According to the further technical scheme, the sliding bearing is embedded in a bearing end cover, and the bearing end cover is fixed at the end part of the outer shell.
In a further technical scheme, the sliding bearing is a graphite copper bearing.
The invention has the beneficial effects that:
(1) the linear electromagnetic dynamic vibration absorber rigidly connected with the outer cylinder of the magnetorheological vibration absorber is a mass-rigidity-damping resonance system acting on a wheel, does not need external control, can effectively reduce the acceleration of a vehicle body, the dynamic load of a tire and the dynamic deflection of a suspension frame in a wheel resonance frequency band, inhibits the vibration of the wheel, and improves the running safety of the electric vehicle driven by a hub motor;
(2) the linear electromagnetic power vibration absorber always works in a passive energy feedback mode, when the stator and the rotor move linearly relatively, the coil winding generates induction current to provide energy for the magnetorheological vibration absorber and realize self-energy supply of the vibration absorber, and meanwhile, the residual energy is stored in the storage battery to realize energy recovery;
(3) the magnetorheological damper with low energy consumption is utilized to inhibit the vibration of the automobile body, and the riding comfort of the hub motor driven electric automobile is improved.
Drawings
FIG. 1 is a schematic structural view of a self-energized magnetorheological damper of an electric vehicle driven by a hub motor according to the invention;
FIG. 2 is a schematic view of a dynamic model of a self-powered magnetorheological damper system of an electric vehicle driven by a hub motor according to the invention;
FIG. 3 is a schematic view of the amplitude-frequency response of the acceleration of the body of the self-energized magnetorheological damper of the electric vehicle driven by the hub motor to the displacement of the road surface according to the invention;
FIG. 4 is a schematic diagram showing the amplitude-frequency response of the dynamic load of the tire of the self-powered magnetorheological damper for an electric vehicle driven by the hub motor to the displacement of the road surface according to the invention;
FIG. 5 is an amplitude-frequency response schematic diagram of dynamic deflection of a suspension of the self-powered magnetorheological damper of the electric automobile driven by the hub motor to road surface displacement.
In the figure: 1. the magnetorheological vibration absorber comprises a magnetorheological vibration absorber, 2 parts of an upper connecting piece, 3 parts of a spiral spring, 4 parts of a spring tray, 5 parts of a lower lifting lug, 6 parts of a linear electromagnetic dynamic vibration absorber, 7 parts of a stator, 8 parts of a central rod, 9 parts of a permanent magnet, 10 parts of an iron core, 11 parts of an annular elastic material, 12 parts of a rotor, 13 parts of a coil winding, 14 parts of a winding iron core, 15 parts of a sliding bearing, 16 parts of a bearing end cover, 17 parts of an outer shell and 18 parts of a C-shaped connecting body.
Detailed Description
The invention will be further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.
As shown in fig. 1, the self-powered magnetorheological damper for the hub motor driven electric automobile comprises a magnetorheological damper 1, an upper connecting piece 2, a spiral spring 3, a spring tray 4, a lower lifting lug 5 and a linear electromagnetic dynamic vibration absorber 6.
The linear electromagnetic dynamic vibration absorber 6 is rigidly connected with the outer cylinder of the magnetorheological vibration absorber 1, and the connection mode comprises the following steps: (1) the C-shaped connecting bodies 18 are rigidly connected in parallel, the C-shaped connecting bodies 18 are connected with the side part of the outer cylinder of the magnetorheological damper 1, and a linear electromagnetic dynamic vibration absorber 6 is arranged in the C-shaped connecting bodies 18; (2) rigid series connection: the C-shaped connecting body 18 is replaced by a cylindrical shell, the linear electromagnetic dynamic vibration absorber 6 is arranged in the cylindrical shell and fixed below the outer cylinder of the magnetorheological vibration absorber 1, and the lower lifting lug 5 is arranged at the lower end of the linear electromagnetic dynamic vibration absorber 6; (3) the linear electromagnetic dynamic vibration absorber 6 takes the outer cylinder of the magnetorheological vibration absorber 1 as a central rod and is integrated on the periphery of the outer cylinder of the magnetorheological vibration absorber 1, the central rod 8 in the figure 1 is omitted, and a cylindrical shell is used for replacing the C-shaped connecting body 18 and is arranged outside the outer cylinder of the magnetorheological vibration absorber 1; the magneto-rheological damper 1 is used for inhibiting the vibration of the electric automobile body driven by the hub motor and improving the riding comfort of the automobile; the linear electromagnetic power device 6 is used for inhibiting the vibration of the wheel of the electric automobile driven by the hub motor and improving the grounding property of the wheel of the automobile.
The embodiment takes the linear electromagnetic dynamic vibration absorber 6 and the outer cylinder of the magnetorheological vibration absorber 1 in rigid parallel connection as an example, and describes the structure and the principle of the self-powered magnetorheological vibration absorber of the electric automobile driven by the hub motor.
The upper end of the outer shell of the magneto-rheological shock absorber 1 is connected with a vehicle body through an upper connecting piece 2, and the lower end of the outer shell of the magneto-rheological shock absorber 1 is connected with a wheel half shaft through a lower lifting lug 5; the spring tray 4 is fixed on the upper part of the shell of the magnetorheological damper 1, and the spiral spring 3 is arranged between the upper connecting piece 2 and the spring tray 4 and is used for supporting the mass of a vehicle body and providing the rigidity of a suspension; the magneto-rheological shock absorber 1 is a semi-active shock absorber, the ECU determines the damping force F of the semi-active shock absorber, and the magneto-rheological shock absorber 1 tracks the damping force.
The linear electromagnetic force vibration absorber 6 consists of a stator 7 and a rotor 12; stator 7 comprises well core rod 8 and permanent magnet 9, and well core rod 8 is fixed inside C shape connector 18, and permanent magnet 9 piles up in well core rod 8 periphery, and permanent magnet 9's the mode of magnetizing includes: 1) an axial magnetizing mode: permanent magnets 9 and iron cores 10 are stacked on the periphery of the central rod 8 alternately in pairs, the permanent magnets 9 adopt an axial magnetizing mode, and the magnetizing directions of adjacent permanent magnets are opposite; 2) and (3) radial magnetizing mode: permanent magnets 9 and iron cores 10 are stacked on the periphery of the central rod 8 alternately in pairs, the permanent magnets 9 adopt a radial magnetizing mode, and the magnetizing directions of adjacent permanent magnets are opposite; 3) a mixed magnetizing mode: the mixed magnetizing mode is a coreless structure, permanent magnets which are axially magnetized and radially magnetized are stacked on the periphery of the central rod 8 in an alternating pair mode, and the magnetizing directions of the adjacent axial permanent magnets and the radial permanent magnets are opposite (the permanent magnets shown in figure 1 adopt axial magnetizing); the central rod 8 is an aluminum central rod, so that the magnetic leakage of the permanent magnet can be reduced, and the total mass of the linear electromagnetic dynamic vibration absorber can be reduced; the upper end and the lower end of the rotor 12 are respectively sleeved with an annular elastic material 11, the annular elastic material 11 is connected with a C-shaped connector 18, the annular elastic material 11 is used for supporting the rotor 12 and meeting the rigidity requirement of the vibration absorber system, and the annular elastic material 11 is a non-metal rubber spring and is prevented from being influenced by a magnetic field; the rotor 12 is composed of a coil winding 13, a winding iron core 14, a sliding bearing 15, a bearing end cover 16 and an outer shell 17, wherein the annular elastic material 11 is sleeved at the upper end and the lower end of the outer shell 17 respectively, the end part of the outer shell 17 is fixedly connected with the bearing end cover 16, the sliding bearing 15 is embedded in the bearing end cover 16, the sliding bearing 15 is in clearance fit with the stator 7, the winding iron core 14 is fixedly connected inside the outer shell 17, and the coil winding 13 is wound on the winding iron core 14; the sliding bearing 15 is a graphite copper bearing, so that the influence of a magnetic field is avoided; the outer shell 17 is made of iron material and is used for packaging the rotor structure assembly and configuring the mass of the vibration absorber system so as to meet the mass requirement of the vibration absorber system.
A schematic diagram of a dynamic model of an in-wheel motor driven electric vehicle with a self-energized magnetorheological damper is shown in FIG. 2, wherein msIs sprung mass, muIs an unsprung mass, mmFor the total mass of the reduction mechanism and the motor, ksFor suspension stiffness, kuAs tire stiffness, zsIs sprung mass displacement, zuFor unsprung mass displacement, zrInputting displacement for road surface, F is damping force of magneto-rheological shock absorber, mdIs the mass, k, of the linear electromagnetic dynamic vibration absorberdFor the stiffness of the vibration absorber, cdIs the electromagnetic damping coefficient, z, of the vibration absorberdThe vibration absorber is vertically displaced. The linear electromagnetic dynamic vibration absorber 6 provides system mass through the rotor 12, the annular elastic material 11 provides system rigidity, the electromagnetic damping generated between the stator 7 and the rotor 12 provides system damping to form a mass-rigidity-damping resonance system acting on the wheels, and the generated reaction force can inhibit the vibration of the wheels in a certain frequency band and improve the grounding performance of the wheels. The linear electromagnetic power vibration absorber 6 always works in a passive energy feedback mode, the permanent magnet 9 generates a fixed magnetic field, and according to the electromagnetic induction law, when the stator 7 and the rotor 12 perform relative linear motion, the coil winding 13 generates induced current so as to convert the mechanical energy of wheel vibration into electric energy, and the super capacitor is used as a primary energy storage device to provide coil excitation current for the magnetorheological vibration absorber 1. Meanwhile, the residual electric energy can charge the storage battery.
In particular, in ms=320kg、mu=35kg、mm=20kg、ks=19600N/m、kuFor example, the suspension system parameter of the 200000N/md in-wheel motor driven electric vehicle 1/4, under which the parameter of the designed linear electromagnetic dynamic vibration absorber 6 is md=5.4kg、kd=17190N/m、cd142N/m, the coil internal resistance R is 3 omega, and the inductance L is 1.7 mH; the linear electromagnetic dynamic vibration absorber 6 is of an 8-pole 9-slot structure, and the coil windings 13 are connected in a three-phase star shape; the length of the stator 7 is 248mm, the radius is 20mm, and the height of the rotor outer shell 17 is 148mm, and the length and the width are 75 mm. The method is characterized in that the traditional hydraulic damper hub motor driven electric automobile is used as a comparison object, the automobile body acceleration, the tire dynamic load and the suspension dynamic deflection are used as vertical dynamics evaluation indexes, and the damping performance of the self-powered magnetorheological damper hub motor driven electric automobile is evaluated. As shown in fig. 3, compared with the conventional hydraulic damper hub motor driven electric automobile, the self-energized magnetorheological damper hub motor driven electric automobile can effectively reduce the acceleration of the automobile body in the wheel resonance frequency band. As shown in fig. 4, compared with the conventional hydraulic damper hub motor driven electric vehicle, the self-energized magnetorheological damper hub motor driven electric vehicle can effectively reduce the dynamic load of the tire in the wheel resonance frequency band. As shown in fig. 5, compared with the conventional hydraulic damper hub motor driven electric automobile, the self-energized magnetorheological damper hub motor driven electric automobile can effectively reduce the dynamic deflection of the suspension in the wheel resonance frequency band.
The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.