阅读说明：本技术 一种可变传动比机构及可变传动比转向系统及其控制方法 (Variable transmission ratio mechanism, variable transmission ratio steering system and control method of variable transmission ratio steering system ) 是由 屈小贞 冯浩轩 李进 李刚 刘丛浩 陈双 于 2019-12-13 设计创作，主要内容包括：本发明公开了一种可变传动比机构,包括：外壳,其内壁沿轴向均布多条直线凹槽；第一端盖,其与外壳一端固定连接,用于将可变传动比机构与转向机构固定；第一电磁铁,其固定在第一端盖内侧；第二端盖,其与第一端盖对称设置,且与外壳另一端固定连接；第二电磁铁,其固定在第二端盖内侧；套筒,其设置在第一电磁铁和第二电磁铁之间,且其靠近第二电磁铁的一端与转向齿轮轴的一端固定连接,套筒的外壁具有曲线凹槽；钢球环形架,套设在套筒外部；多个钢球,其可转动的均布在钢球环形架上,钢球的内侧与所述曲线凹槽相匹配,外侧与直线凹槽相匹配。本发明公开了一种可变传动比转向系统及其控制方法。(The invention discloses a variable transmission ratio mechanism, comprising: the inner wall of the shell is uniformly provided with a plurality of linear grooves along the axial direction; the first end cover is fixedly connected with one end of the shell and used for fixing the variable transmission ratio mechanism and the steering mechanism; a first electromagnet fixed inside the first end cap; the second end cover is symmetrically arranged with the first end cover and is fixedly connected with the other end of the shell; the second electromagnet is fixed on the inner side of the second end cover; the sleeve is arranged between the first electromagnet and the second electromagnet, one end of the sleeve, which is close to the second electromagnet, is fixedly connected with one end of the steering gear shaft, and the outer wall of the sleeve is provided with a curved groove; the steel ball annular frame is sleeved outside the sleeve; and the steel balls are uniformly distributed on the steel ball annular frame in a rotating way, the inner sides of the steel balls are matched with the curve grooves, and the outer sides of the steel balls are matched with the linear grooves. The invention discloses a variable transmission ratio steering system and a control method thereof.)

1. A variable ratio mechanism comprising:

the inner wall of the shell is uniformly provided with a plurality of linear grooves along the axial direction;

the first end cover is fixedly connected with one end of the shell and used for fixing the variable transmission ratio mechanism and the steering mechanism;

a first electromagnet fixed inside the first end cap;

the second end cover is symmetrically arranged with the first end cover and is fixedly connected with the other end of the shell;

the second electromagnet is fixed on the inner side of the second end cover;

the sleeve is arranged between the first electromagnet and the second electromagnet, one end of the sleeve, close to the second electromagnet, is fixedly connected with one end of the steering gear shaft, and the outer wall of the sleeve is provided with a curved groove;

the steel ball annular frame is sleeved outside the sleeve;

the steel balls are uniformly distributed on the steel ball annular frame in a rotating way, the inner sides of the steel balls are matched with the curve grooves, and the outer sides of the steel balls are matched with the linear grooves;

when the steel ball annular frame moves along the axial direction of the sleeve, the steel ball can move in the linear groove and the curved groove at the same time, so that the shell and the sleeve can rotate relatively.

2. The variable ratio mechanism of claim 1, further comprising:

a first sealed accommodating cavity is formed among the sleeve, the first electromagnet and the shell;

a second sealed accommodating cavity is formed among the sleeve, the second electromagnet and the shell;

a first oil chamber passage provided inside the sleeve and the steering gear shaft;

a first inner oil hole provided in the sleeve, disposed in the first seal accommodating chamber, and communicated with the first oil chamber passage;

a first outer oil hole provided in the steering gear shaft and communicating with the first oil chamber passage;

a second oil chamber passage provided inside the sleeve and the steering gear shaft;

a second inner oil hole provided in the sleeve, disposed in the second seal accommodating chamber, and communicated with the second oil chamber passage;

and a second external oil hole provided at the steering gear shaft and communicating with the second oil chamber passage.

3. The variable ratio mechanism of claim 2, further comprising:

the first check valves are uniformly distributed on the steel ball annular frame along the circumferential direction;

the second check valves are uniformly distributed on the steel ball annular frame along the circumferential direction;

an electromagnetic directional valve communicating with both the first outer oil hole and the second outer oil hole;

the oil pump is connected with the electromagnetic directional valve;

an oil tank connected to the oil pump;

the overflow valve is connected with the electromagnetic directional valve;

the pressure reducing valve is connected with the electromagnetic reversing valve;

the first check valve and the second check valve are opposite in installation direction and are arranged in a staggered mode.

4. The variable transmission ratio mechanism according to any one of claims 1 to 3, further comprising:

a first seal ring disposed between the first end cap and the first electromagnet;

and the second sealing ring is arranged between the second end cover and the second electromagnet.

5. The variable ratio mechanism of claim 4 wherein the linear grooves and the curvilinear grooves are of equal depth.

6. The variable ratio mechanism of claim 4, wherein the depth of the linear groove and the curvilinear groove are each one-third of the diameter of the steel ball.

7. A variable transmission ratio steering system, characterized in that a variable transmission ratio mechanism according to any one of claims 1 to 6 is used, comprising:

a steering mechanism, comprising:

a steering wheel;

one end of the first steering shaft is fixedly connected with the steering wheel;

one end of the first universal joint is connected with the other end of the steering shaft;

one end of the second steering shaft is connected with the other end of the first universal joint;

the driving motor drives the second steering shaft to rotate through a speed reducing mechanism;

one end of the second universal joint is connected with the other end of the second steering shaft;

one end of the variable transmission ratio mechanism is connected with the other end of the second universal joint, and the other end of the variable transmission ratio mechanism is rotatably supported on the steering gear shaft;

and the control circuit is used for controlling the change of magnetic poles and magnetic force at two ends of the first electromagnet and the second electromagnet so as to enable the steel ball annular frame to axially move on the sleeve.

8. A control method of a variable transmission ratio steering system, characterized by using the variable transmission ratio steering system according to claim 7, comprising:

when the vehicle starts or runs at a low speed, the control circuit is in a disconnected state, and the steel ball annular frame is positioned in the middle of the sleeve;

when the vehicle speed changes from low-speed running to high-speed running, the control circuit is in a power-on state, and the steel ball annular frame moves along the axial direction of the sleeve by controlling the magnetic force and the magnetic pole direction of the first electromagnet and the second electromagnet, so that the transmission ratio of the variable transmission ratio mechanism is increased;

when the speed of the vehicle changes from high-speed running to low-speed running, the control circuit is in a power-on state, and the steel ball annular frame moves along the axial direction of the sleeve by controlling the magnetic force and the magnetic pole direction of the first electromagnet and the second electromagnet, so that the transmission ratio of the variable transmission ratio mechanism is reduced.

9. The control method of a variable transmission ratio steering system according to claim 8,

when the vehicle speed changes from low-speed running to high-speed running, the control circuit controls the magnetic force magnitude and the magnetic pole direction of the first electromagnet and the second electromagnet to comprise: when the steering wheel is rotated rightwards, the steel ball annular frame is controlled to move axially along the sleeve in the direction of the second end cover, so that the transmission ratio of the variable transmission ratio mechanism is increased; when the steering wheel is rotated to the left, the steel ball annular frame is controlled to move axially along the sleeve in the direction of the first end cover, so that the transmission ratio of the variable transmission ratio mechanism is increased; and

when the vehicle speed changes from high-speed running to low-speed running, the control circuit controls the magnetic force magnitude and the magnetic pole direction of the first electromagnet and the second electromagnet to comprise: when the steering wheel is turned rightwards, the steel ball annular frame is controlled to move axially along the sleeve towards the first end cover, so that the transmission ratio of the variable transmission ratio mechanism is reduced; when the steering wheel is rotated to the left, the steel ball annular frame is controlled to move axially along the sleeve in the direction of the second end cover, so that the transmission ratio of the variable transmission ratio mechanism is reduced.

10. The control method of a variable transmission ratio steering system according to claim 8, wherein the magnetic force is calculated by:

wherein I is coil current, W is the number of coil turns, μ₀Is the permeability coefficient of the oil, delta is the working air gap length, R₁And R₂The outer radius and the inner radius of the outer ring of the electromagnet magnetizer R₃And R₄The outer radius and the inner radius of a circular ring in the magnetic conductor of the electromagnet.

Technical Field

The invention relates to the technical field of motor vehicle steering control, in particular to a variable transmission ratio mechanism, a variable transmission ratio steering system and a control method thereof.

Background

With the development of automobile technology, the safety and stability of automobiles become increasingly important, and the steering system for controlling the traveling direction of automobiles is particularly important for the safety of automobile driving. In actual driving, the expected automobile steering system has a small steering transmission ratio at low speed and a large steering transmission ratio at high speed. The conventional steering system of the traditional automobile has the steering wheel and front wheel steering angle ratio which is always fixed and unchanged no matter the automobile runs at low speed or high speed.

Compared with the conventional steering system, the variable transmission ratio type steering system has a more direct steering transmission ratio, and the corresponding steering transmission ratio can be switched in time according to the change of the vehicle speed. The variable transmission ratio type steering system can change the steering transmission ratio in real time according to the change of the vehicle speed to adjust the corresponding front wheel rotating angle, and does not influence the control response of the steering system. When the vehicle speed is in a lower range, the vehicle becomes more flexible and easier to operate and control; in a higher vehicle speed range, the steering transmission ratio of the variable transmission ratio type steering system is more indirectly used for guaranteeing the operation stability of the vehicle.

Disclosure of Invention

The invention discloses a variable transmission ratio mechanism, which aims to realize relative rotation of a shell connected with a steering shaft and a sleeve connected with a steering gear by driving a steel ball annular frame structure to slide under the action of magnetic force.

The invention discloses a variable transmission ratio steering system, and aims to provide a variable transmission ratio type steering system which can realize relative rotation of a shell connected with a steering shaft and a sleeve connected with a steering device by driving a steel ball annular frame structure to slide under force action.

The invention designs and develops a control method of a variable transmission ratio steering system, and aims to enable the steering transmission ratio to be in an ideal state along with the change of the vehicle speed so as to ensure the flexibility of the vehicle steering system at low speed and the control stability at high speed.

The technical scheme provided by the invention is as follows:

a variable ratio mechanism comprising:

the inner wall of the shell is uniformly provided with a plurality of linear grooves along the axial direction;

the first end cover is fixedly connected with one end of the shell and used for fixing the variable transmission ratio mechanism and the steering mechanism;

a first electromagnet fixed inside the first end cap;

the second end cover is symmetrically arranged with the first end cover and is fixedly connected with the other end of the shell;

the second electromagnet is fixed on the inner side of the second end cover;

the sleeve is arranged between the first electromagnet and the second electromagnet, one end of the sleeve, close to the second electromagnet, is fixedly connected with one end of the steering gear shaft, and the outer wall of the sleeve is provided with a curved groove;

the steel ball annular frame is sleeved outside the sleeve;

the steel balls are uniformly distributed on the steel ball annular frame in a rotating way, the inner sides of the steel balls are matched with the curve grooves, and the outer sides of the steel balls are matched with the linear grooves;

when the steel ball annular frame moves along the axial direction of the sleeve, the steel ball can move in the linear groove and the curved groove at the same time, so that the shell and the sleeve can rotate relatively.

Preferably, the method further comprises the following steps:

a first sealed accommodating cavity is formed among the sleeve, the first electromagnet and the shell;

a second sealed accommodating cavity is formed among the sleeve, the second electromagnet and the shell;

a first oil chamber passage provided inside the sleeve and the steering gear shaft;

a first inner oil hole provided in the sleeve, disposed in the first seal accommodating chamber, and communicated with the first oil chamber passage;

a first outer oil hole provided in the steering gear shaft and communicating with the first oil chamber passage;

a second oil chamber passage provided inside the sleeve and the steering gear shaft;

a second inner oil hole provided in the sleeve, disposed in the second seal accommodating chamber, and communicated with the second oil chamber passage;

and a second external oil hole provided at the steering gear shaft and communicating with the second oil chamber passage.

Preferably, the method further comprises the following steps:

the first check valves are uniformly distributed on the steel ball annular frame along the circumferential direction;

the second check valves are uniformly distributed on the steel ball annular frame along the circumferential direction;

an electromagnetic directional valve communicating with both the first outer oil hole and the second outer oil hole;

the oil pump is connected with the electromagnetic directional valve;

an oil tank connected to the oil pump;

the overflow valve is connected with the electromagnetic directional valve;

the pressure reducing valve is connected with the electromagnetic reversing valve;

the first check valve and the second check valve are opposite in installation direction and are arranged in a staggered mode.

Preferably, the method further comprises the following steps:

a first seal ring disposed between the first end cap and the first electromagnet;

and the second sealing ring is arranged between the second end cover and the second electromagnet.

Preferably, the linear grooves and the curved grooves have the same depth.

Preferably, the depth of the linear groove and the depth of the curved groove are both one third of the diameter of the steel ball.

A variable ratio steering system using said variable ratio mechanism, comprising:

a steering mechanism, comprising:

a steering wheel;

one end of the first steering shaft is fixedly connected with the steering wheel;

one end of the first universal joint is connected with the other end of the steering shaft;

one end of the second steering shaft is connected with the other end of the first universal joint;

the driving motor drives the second steering shaft to rotate through a speed reducing mechanism;

one end of the second universal joint is connected with the other end of the second steering shaft;

one end of the variable transmission ratio mechanism is connected with the other end of the second universal joint, and the other end of the variable transmission ratio mechanism is rotatably supported on the steering gear shaft;

and the control circuit is used for controlling the change of magnetic poles and magnetic force at two ends of the first electromagnet and the second electromagnet so as to enable the steel ball annular frame to axially move on the sleeve.

A control method of a variable transmission ratio steering system using the variable transmission ratio steering system, comprising:

when the vehicle starts or runs at a low speed, the control circuit is in a disconnected state, and the steel ball annular frame is positioned in the middle of the sleeve;

when the vehicle speed changes from low-speed running to high-speed running, the control circuit is in a power-on state, and the steel ball annular frame moves along the axial direction of the sleeve by controlling the magnetic force and the magnetic pole direction of the first electromagnet and the second electromagnet, so that the transmission ratio of the variable transmission ratio mechanism is increased;

when the speed of the vehicle changes from high-speed running to low-speed running, the control circuit is in a power-on state, and the steel ball annular frame moves along the axial direction of the sleeve by controlling the magnetic force and the magnetic pole direction of the first electromagnet and the second electromagnet, so that the transmission ratio of the variable transmission ratio mechanism is reduced.

It is preferable that the first and second liquid crystal layers are formed of,

when the vehicle speed changes from low-speed running to high-speed running, the control circuit controls the magnetic force magnitude and the magnetic pole direction of the first electromagnet and the second electromagnet to comprise: when the steering wheel is rotated rightwards, the steel ball annular frame is controlled to move axially along the sleeve in the direction of the second end cover, so that the transmission ratio of the variable transmission ratio mechanism is increased; when the steering wheel is rotated to the left, the steel ball annular frame is controlled to move axially along the sleeve in the direction of the first end cover, so that the transmission ratio of the variable transmission ratio mechanism is increased; and

when the vehicle speed changes from high-speed running to low-speed running, the control circuit controls the magnetic force magnitude and the magnetic pole direction of the first electromagnet and the second electromagnet to comprise: when the steering wheel is turned rightwards, the steel ball annular frame is controlled to move axially along the sleeve towards the first end cover, so that the transmission ratio of the variable transmission ratio mechanism is reduced; when the steering wheel is rotated to the left, the steel ball annular frame is controlled to move axially along the sleeve in the direction of the second end cover, so that the transmission ratio of the variable transmission ratio mechanism is reduced.

Preferably, the magnetic force is calculated by:

wherein I is coil current, W is the number of coil turns, μ₀Is the permeability coefficient of the oil, delta is the working air gap length, R₁And R₂The outer radius and the inner radius of the outer ring of the electromagnet magnetizer R₃And R₄The outer radius and the inner radius of a circular ring in the magnetic conductor of the electromagnet.

Compared with the prior art, the invention has the following beneficial effects: the variable transmission ratio mechanism and the variable transmission ratio steering system provided by the invention have the characteristics of simple structure, good stability and the like, the variable steering transmission ratio requirements under different vehicle speeds are realized by driving the steel ball annular frame to slide left and right under the action of magnetic force, and the steering transmission ratio is always in an ideal state along with the change of the vehicle speed, so that the flexibility of the vehicle steering system under low speed and the control stability under high speed are ensured.

Drawings

Fig. 1 is a structural assembly layout diagram of a variable transmission ratio steering system according to the present invention.

Fig. 2 is a structural view of a housing of the variable transmission ratio mechanism according to the present invention.

Fig. 3 is an internal structural view of the variable transmission ratio mechanism according to the present invention.

Fig. 4 is a structural view of a ball ring carrier of the variable transmission ratio mechanism according to the present invention.

Fig. 5 is a schematic structural view of a one-way ball valve of the variable transmission ratio mechanism according to the present invention.

Fig. 6 is a left end cap structure of the variable ratio mechanism of the present invention.

Fig. 7 is a right end cover structure view of the variable transmission ratio mechanism according to the present invention.

Fig. 8 is a cross-sectional view of the solenoid coil of the variable ratio mechanism of the present invention.

Fig. 9 is a structural view of an electromagnet mounting position of the variable transmission ratio mechanism according to the present invention.

Fig. 10 is a control circuit diagram of the variable ratio steering system of the present invention.

FIG. 11 is a schematic representation of the forward current pole change of the variable ratio steering system of the present invention.

FIG. 12 is a schematic representation of the reverse current pole change of the variable ratio steering system of the present invention.

FIG. 13 is a schematic illustration of a solenoid directional valve connection neutral path of the variable ratio steering system of the present invention.

FIG. 14 is a schematic view of the solenoid directional valve communication left channel of the variable ratio steering system of the present invention.

FIG. 15 is a schematic diagram of the solenoid directional valve connection right channel of the variable ratio steering system of the present invention.

Detailed Description

The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.

As shown in fig. 1, the present invention provides a variable transmission ratio steering system, which is operated by the rotation of a steering wheel 101 to drive a steering shaft 102 to rotate, and a driving motor 106 drives the steering shaft 102b through a reduction gear 107 to implement electric power steering, when the steering wheel 101 is rotated, an electronic control unit determines how much power is provided by the driving motor 106 according to a torque signal and a vehicle speed signal obtained by a sensor and according to a power curve calibrated by the electronic control unit, and the torque provided by the driving motor 106 is amplified by the reduction gear 107 connected thereto and transmitted to the steering shaft 102 b.

The steering shaft 102 is connected to a right end cover 207 of the variable transmission ratio mechanism 108 through a pair of universal joints 105a and 105b, and then connected to a rack and pinion steering gear 110 through a steering gear shaft 111, a steering gear 1101 in the steering gear is fixed at one end of the steering gear shaft 111, a steering sleeve 104 is sleeved outside the steering shaft 102, and the steering control mechanism is supported and fixed by a bracket assembly 103 and is adjustable in position.

As shown in fig. 2 and 3, the present invention provides a variable transmission ratio mechanism, which is composed of an internal structure and a housing 209 structure, and two ends are respectively and hermetically supported by a left end cover 201 and a right end cover 207.

As shown in fig. 2, six uniformly distributed linear grooves 2091 are formed in the inner wall of the housing 209, the linear grooves 2091 penetrate through two ends of the inner wall of the housing 209, and the depth of each groove of each linear groove 2091 is equal to the diameter of the circumference of one third of the steel ball 2051.

As shown in fig. 3, the sleeve 208 is fixed to the right end of the steering gear shaft 111 by interference fit, and the oil supply holes of the sleeve 208 and the oil supply holes of the steering gear shaft 111 are overlapped to ensure the smooth connection of the oil holes 109a and 204a, 109b and 204b, and the two corresponding connecting oil passages are disposed in the steering gear shaft 111.

As shown in fig. 3, the outer wall of the sleeve 208 and the inner wall of the housing 209 are respectively provided with six corresponding curved grooves 2081 and linear grooves 2091; the curved groove 2081 penetrates through two ends of the sleeve 208, the rotation direction of the groove is as shown in fig. 3 (that is, when the steel ball annular frame 205 moves axially along the sleeve 208 towards the left end cover 201, the steering gear shaft 111 rotates clockwise), and the circumferential angle of the curved groove 2081 longitudinally across the sleeve 208 is not less than 720 degrees (on the premise of meeting the design requirement of the sleeve shaft diameter, the ratio of the sleeve length to the sleeve shaft diameter should not be less than 4).

As shown in fig. 4, the annular steel ball holder 205 is mounted at the middle position on the outer wall of the sleeve 208, six steel balls 2051 are uniformly arranged on the circumference of the annular steel ball holder 205 and respectively correspond to six linear grooves 2091 on the inner wall of the housing 209 and six curved grooves 2081 on the outer wall of the sleeve 208, the middle 1/3 structure of the steel balls 2051 is arranged in the annular steel ball holder 205, and the upper and lower 1/3 ball structures of the steel balls are respectively matched with the groove depths of the linear grooves 2091 on the inner wall of the housing 209 and the curved grooves 2081 on the outer wall of the sleeve 208; in this embodiment, during assembly, steel ball 2051 and ring-shaped steel ball holder 205 are assembled by a hot-assembly process, and assembled steel ball 2051 can rotate in ring-shaped steel ball holder 205.

As shown in fig. 4 and 5, six one- way ball valves 2053 and 2054 are uniformly distributed on the circumference of the steel ball annular frame 205, the one- way ball valves 2053 and 2054 are arranged at intervals and are opposite in installation direction, the one-way ball valves 2053 and the one-way ball valves 2054 can be gradually opened in a one-way mode only when the oil pressure of oil reaches a certain critical value, and oil seals 2052 are added at two ends of the inner side and the outer side of the steel ball annular frame 205 so as to reduce the gap flow effect generated by the oil between the outer wall of the sleeve 208 and the inner wall of the shell 209 when the steel ball annular frame 205 slides left and.

As shown in fig. 6 and 7, the variable transmission ratio mechanism 108 is a sealing device composed of a left end cap 201, a right end cap 207, and left and right sealing rings 202 thereof, and is divided into left and right sealing cavities by a steel ball annular frame 205; the left end cover and the right end cover are fixedly connected to two ends of the shell 209 through bolts, the left end electromagnet 203 and the right end electromagnet 206 are respectively and fixedly connected to the left end cover 201 and the right end cover 207, and in order to guarantee smooth power supply of spiral coils of the electromagnets at the two ends in the rotating process, spiral coil connectors of the electromagnets at the two ends need to be respectively led out through the corresponding end covers to be connected to corresponding circuit slide sheet leads.

As shown in fig. 8, the left end electromagnet 203 and the right end electromagnet 206 are formed by an inner layer and an outer layer of circular ring magnetizers and a superconducting coil between the two layers, the left end electromagnet 203 and the right end electromagnet 206 are respectively supported on the steering gear shaft 111 through bearings 210a and 210b, and the electromagnets and the end covers synchronously rotate and can realize relative rotation with the steering gear shaft 111.

The steel ball annular frame 205 divides the sealed cavity formed between the sleeve 208 and the housing 209 into two left and right sealed oil chambers, namely a left oil chamber corresponding to the oil hole 204a and a right oil chamber corresponding to the oil hole 204b, and the oil in the left and right oil chambers is supplied or overflowed through the oil hole 109a and the oil hole 109 b.

As shown in fig. 9 and 13 to 15, the oil holes 109a and 109b are provided in an annular groove formed in the steering gear shaft 111, and the annular groove formed in the steering gear shaft 111 overlaps the supply oil passage in the supporting device thereof and is connected to the supply oil tank 305 through the electromagnetic directional valve 301 to ensure smooth connection of the oil holes 109a and 109b with the oil passage when the oil holes 109a and 109b rotate with the steering gear shaft 111.

As shown in fig. 13 to 15, the engine ECU controls the electromagnetic directional valve 301 according to real-time conditions to change the position of the valve core in the directional valve, controls two channels of the left position, the middle position and the right position of the electromagnetic directional valve 301 to be connected with the oil holes 109a and 109b on the steering gear shaft 111 respectively, and further changes the flow direction and the oil pressure of oil in the oil path, before the channels are switched by the electromagnetic directional valve 301, the overflow valve 303 and the pressure reducing valve 304 are automatically opened to balance the oil pressure of the oil in the oil chambers on both sides until the oil pressure of the oil in the oil chambers on both sides can keep the steel ball annular frame 205 in a relatively static.

As shown in fig. 10 to 12, the control circuit for controlling the current of the left electromagnet 203 and the right electromagnet 206 can change the magnetic pole transformation of the two ends of the left electromagnet 203 and the right electromagnet 206 by changing the current direction; when the steel ball annular frame 205 is manufactured, a permanent magnetic material with stronger magnetism is selected for processing, the corresponding left and right annular end surfaces of the steel ball annular frame are respectively two magnetic poles (N and S), and the sleeve 208 and the steel ball 205 are both processed by a magnetic insulation material with better strength so as to prevent the steel ball annular frame from being magnetized.

As shown in fig. 11 and 12, the left end electromagnet 203 and the right end electromagnet 206 are circular ring electromagnets with the same type and the same attribute, so as to ensure that the end magnetic poles corresponding to the two electromagnets after being installed in the variable transmission ratio mechanism 108 and being powered on are always the same, and the magnetic force of the left end electromagnet 203 and the right end electromagnet 206 is ensured by changing the number of turns of the winding coil and the magnitude of the circulating current, and the corresponding magnetic force formula is as follows:

wherein I is coil current, W is the number of coil turns, μ₀Is the permeability coefficient of the oil, delta is the working air gap length, R₁And R₂The outer radius and the inner radius of the outer ring of the electromagnet magnetizer R₃And R₄The outer radius and the inner radius of a circular ring in the magnetic conductor of the electromagnet.

As shown in fig. 10 and table 1, the control circuit is connected to the vehicle power supply through the port of the single chip, the triode, the not gate, the spiral coil, the variable resistor, and the like, and when the ENABLE signal ENABLE outputs signal 1, the signal terminal DIR1 outputs signal 0, and the signal terminal DIR2 outputs signal 1; the NOT gate U1A converts the signal 0 into the signal 1, the AND gate U3A outputs the signal 1, and the transistor Q1 is connected; and gate U4A outputs signal 0 and transistor Q2 is open circuited. The AND gate U6A outputs a signal 1, the triode Q4 is connected, the NOT gate U2A converts the signal 1 output by the DIR2 into a signal 0, the AND gate U5A outputs the signal 0, and the triode Q3 is disconnected; at this time, the current direction is defined as the positive direction, and the current passes through the transistor Q1, the spiral coils L1 and L2, and the transistor Q4 from the power supply end, wherein the winding directions of the spiral coils L1 and L2 are required to ensure that the magnetic poles at the two ends of the left electromagnet 203 and the right electromagnet 206 are changed as shown in fig. 11.

When the ENABLE signal ENABLE outputs signal 1, the signal terminal DIR1 outputs signal 1, and the signal terminal DIR2 outputs signal 0; the NOT gate U1A converts the signal 1 into a signal 0, the AND gate U3A outputs the signal 0, and the triode Q1 is disconnected; and gate U4A outputs signal 1, transistor Q2 path. The AND gate U6A outputs a signal 0, the triode Q4 is disconnected, the NOT gate U2A converts the signal 0 output by the DIR2 into a signal 1, the AND gate U5A outputs the signal 1, and the triode Q3 is connected; at this time, the current direction is defined as the reverse direction, the current passes through the transistor Q3, the spiral coils L2 and L1, and the transistor Q2 from the power supply terminal, and the current passes through the spiral coils L1 and L2 to make the magnetic poles at the two ends of the left electromagnet 203 and the right electromagnet 206 as shown in fig. 12.

TABLE 1 control circuit signal table

ENABLE	1	1	0
				DIR1	0	1	0
DIR2	1	0	0
				Direction of current flow	Forward direction	Reverse direction	At rest

The current flowing through the spiral coils L1 and L2 in the control circuit is adjusted through the variable resistors R1 and R2, so that the magnetic force of the left end electromagnet 203 and the right end electromagnet 206 is changed to control the interaction force between the permanent magnet steel ball annular frame 205 and the permanent magnet steel ball annular frame 205, and the aim of adjusting and controlling the sliding speed of the steel ball annular frame 205 is fulfilled; when the ENABLE signal terminals ENABLE, DIR1 and DIR2 output signals 0, all the triodes are open-circuit, no current is generated in the circuit, and the magnetic force of the left electromagnet 203 and the right electromagnet 206 disappears.

The steel ball annular frame 205 slides left and right through the magnetic force change of the left end electromagnet 203 and the right end electromagnet 206 and the oil pressure change in the left and right oil chambers.

As shown in fig. 13, in the initial position, the steel ball ring 205 is held stationary at the middle position of the sleeve 208, the electromagnetic directional valve 301 is connected to the middle passage, the oil pressures in the left and right oil chambers are equal, and the housing 209 and the sleeve 208 or the steering gear shaft 111 do not rotate relatively. At this time, the variable transmission ratio mechanism 108 rotates synchronously with the steering shaft 102 as an integral structure in the steering system, and the addition of the variable transmission ratio mechanism 108 does not affect the reversible effect of the steering system.

When the ENABLE signal ENABLE of the control circuit outputs signal 1, the signal end DIR1 outputs signal 0, and the signal end DIR2 outputs signal 1; when the current in the control circuit flows through the transistor Q1, the spiral coils L1 and L2, and the transistor Q4, the magnetic poles at the two ends of the left electromagnet 203 and the right electromagnet 206 change as shown in fig. 11. At this time, the steel ball annular frame 205 as a permanent magnet slides to the right end under the action of magnetic force (the same poles on the left repel each other to form thrust, and the opposite poles on the right attract each other to form tension) on the two sides. The oil pressure in the right oil chamber gradually increases, the check ball valve 2054 is kept in a closed state, the check ball valve 2053 is opened, and the oil in the right oil chamber flows into the left oil chamber through the check ball valve 2053.

As shown in fig. 14, the oil hole 204a and the oil hole 204b are connected to the oil tank through the oil hole 109a and the oil hole 109b via the electromagnetic directional valve 301, at this time, the oil in the oil tank 305 is pumped into the left oil chamber through the oil hole 109a via the oil pump 302 to supplement the cavity after the steel ball annular frame 205 slides to the right, and the relief valve 303 ensures that the oil pressure is not greater than the oil pressure in the right oil chamber, and the relief valve 304 connected to the outlet of the oil hole 109b overflows the excess oil in the right oil chamber to reduce the oil pressure in the oil chamber, so as to ensure that the oil pressure in the right oil chamber is always less than the magnetic attraction force between the right electromagnet 206 and the steel ball annular frame 205 before the steel.

According to the real-time position of the steel ball annular frame 205 measured by the position sensor, the sliding speed of the steel ball annular frame 205 is gradually reduced until the steel ball annular frame reaches the target position by adjusting the current in the control circuit and the oil pressure change of oil in oil chambers at two sides. When the steel ball annular frame 205 slides to a target position, the vehicle electronic control unit controls the electromagnetic reversing valve 301 to connect an oil passage to be switched to a middle position, at the moment, an oil passage supply system is interrupted, the one-way ball valve 2053 and the one-way ball valve 2054 are kept in a closed state, oil in the variable transmission ratio mechanism 108 and the steel ball annular frame 205 are in a static balance state, meanwhile, a control circuit where the left end electromagnet 203 and the right end electromagnet 206 are located is in a disconnected state, and the magnetic action between the permanent magnet steel ball annular frame 205 and the electromagnets at two ends can keep the balance state by calibrating the oil pressure of the oil in the oil chambers at two sides.

Because the curved groove 2081 and the straight groove 2091 corresponding to the steel ball 2051 are arranged in a crossed manner, when the steel ball annular frame 205 slides left and right along the curved groove 2081 and the straight groove 2091, the crossed position of the curved groove 2081 and the straight groove 2091 changes constantly, and the sleeve 208 and the shell 209 are urged to rotate relatively. The steel ball annular frame 205 slides to the right along the tracks of the curved groove 2081 and the straight groove 2091 corresponding to the upper part and the lower part of the steel ball 2051, so that the sleeve 208 rotates by a certain circumferential angle in advance or in delay relative to the shell 209. Therefore, the transmission ratio of the steering shaft 102 to the steering gear shaft 111 changes with the left-right sliding of the steel ball annular frame 205, and the change range is that the sleeve 208 rotates relative to the housing 209 through the circumferential angle corresponding to the sliding of the steel ball 2051 through the curved groove 2081.

At this time, if the steering wheel 101 is rotated to the right, as shown in fig. 3, the curved groove 2081 is rotated, and the housing 209 and the steering shaft 102 rotate synchronously, the sleeve 208 rotates relative to the steering shaft 102 by a certain circumferential angle which is equal to the circumferential angle corresponding to the sliding of the steel ball 2051 through the curved groove 2081, and as a result, the steering gear shaft 111 and the steering gear 1101 rotate relative to the steering shaft 102 by a certain angle, so that the steering wheel rotation angle corresponding to the steering gear 110 increases, and the variable transmission ratio mechanism 108 decreases the steering transmission ratio of the steering system, which is equal to the circumferential angle rotated by the steering gear shaft 111/the circumferential angle rotated by the steering wheel 101.

Conversely, when the steering wheel 101 is turned to the left, as shown in fig. 3, the curved groove 2081 turns, the sleeve 208 rotates less by a certain circumferential angle with respect to the steering shaft 102, which is equal to the circumferential angle by which the steel balls 2051 slide through the curved groove 2081, with the result that the steering gear shaft 111 and the steering gear 1101 rotate less by a certain angle with respect to the steering shaft 102, so that the steering wheel angle corresponding to the steering gear 110 decreases, and the variable gear ratio mechanism 108 increases the steering gear ratio of the steering system by the circumferential angle by which the steering gear shaft 111 rotates/the circumferential angle by which the steering wheel 101 rotates.

When the ENABLE signal ENABLE of the control circuit outputs signal 1, the signal end DIR1 outputs signal 1, and the signal end DIR2 outputs signal 0; when the current in the control circuit flows through the transistor Q3, the spiral coils L2 and L1, and the transistor Q2, the magnetic poles at the two ends of the left electromagnet 203 and the right electromagnet 206 change as shown in fig. 12.

As shown in fig. 15, the oil hole 204a and the oil hole 204b are already connected to the oil tank through the oil hole 109a and the oil hole 109b by the electromagnetic directional valve 301, the steel ball ring frame 205 slides to the left under the action of magnetic force, the oil pressure in the left oil chamber gradually increases, the check ball valve 2053 is kept closed, the check ball valve 2054 is opened, and the oil in the left oil chamber flows into the right oil chamber through the check ball valve 2054; oil in the oil tank 305 is pumped into the right oil cavity through the oil hole 109b by the oil pump 302 to supplement the cavity of the steel ball annular frame 205 after sliding leftwards, and the overflow valve 303 ensures that the oil pressure is not greater than the oil pressure in the left oil cavity. The pressure reducing valve 304 connected with the outlet of the oil hole 109a overflows the redundant oil in the left oil cavity to reduce the oil pressure in the oil cavity, so that the oil pressure in the left oil cavity is always smaller than the magnetic attraction force between the left electromagnet 203 and the steel ball annular frame 205 before the steel ball annular frame 205 reaches the target position until the steel ball annular frame 205 reaches the specified target position along with the change of the magnetic force at the two ends and the change of the oil pressure in the oil cavities at the two sides.

At this time, if the steering wheel 101 is rotated to the right, as shown in fig. 3, the curved groove 2081 rotates in the same direction, and the housing 209 and the steering shaft 102 rotate synchronously, the sleeve 208 rotates less than a certain circumferential angle relative to the steering shaft 102, which is equal to the circumferential angle corresponding to the steel ball 2051 sliding through the curved groove 2081; as a result, the steering gear shaft 111 and the steering gear 1101 rotate less by a certain angle with respect to the steering shaft 102, so that the steering wheel angle corresponding to the steering gear 110 decreases, and the variable transmission ratio mechanism 108 increases the steering transmission ratio of the steering system by the circumferential angle rotated by the steering gear shaft 111/the circumferential angle rotated by the steering wheel 101.

Conversely, when the steering wheel 101 is turned to the left, as shown in fig. 3, the curved groove 2081 rotates, the sleeve 208 rotates relative to the steering shaft 102 by a certain circumferential angle, which is equal to the circumferential angle of the steel ball 2051 sliding through the curved groove 2081; as a result, the steering gear shaft 111 and the steering gear 1101 are rotated by a certain angle with respect to the steering shaft 102, so that the steering wheel rotation angle corresponding to the steering gear 110 is increased, and the variable transmission ratio mechanism 108 reduces the steering transmission ratio of the steering system, which is the circumferential angle rotated by the steering gear shaft 111/the circumferential angle rotated by the steering wheel 101.

The transmission ratio of the variable transmission ratio steering system is:

i＝i₁×i₂×i₃；

in the formula i₁(i₁The circumferential angle through which the steering gear shaft 111 rotates/the circumferential angle through which the steering wheel 101 rotates) is the gear ratio of the variable gear ratio mechanism 108, i₂To the steering gear angle ratio, i₃The angle transmission ratio of the steering transmission mechanism is set; and i is₁The continuous conversion can be realized according to the change of the running speed of the vehicle so as to meet the requirement of the running steering transmission ratio;

the vehicle control unit can control the current direction in the circuit to change the magnetic pole change of the electromagnet and control the connecting channel of the electromagnetic directional valve 301 to change the oil pressure change of oil in the oil cavities at two sides through the vehicle speed change and the driving requirement real-time control according to the real-time vehicle speed, the working condition of the engine and other parameters detected by different sensors, so as to drive the steel ball annular frame 205 to slide left and right, further change the transmission ratio of the variable transmission ratio mechanism 108, finally realize the conversion requirement of the steering transmission ratio under different vehicle speeds, and meet the driving steering requirement.