CN206719313U - A kind of electronic and automatically controlled two-in-one hydraulic power-assist steering system - Google Patents

Abstract

The utility model provides an electric and electric control two-in-one hydraulic power steering system, which comprises a steering control unit, a hydraulic power boosting pipeline and a steering oil pump arranged on the hydraulic power boosting pipeline, and a solenoid valve is also arranged on the hydraulic power boosting pipeline , the steering motor drives the steering oil pump, and the steering control unit is connected with the solenoid valve and the steering motor. Under normal circumstances, the system works in the electric control mode. If the electric control mode fails, it will switch to the electric mode. The utility model effectively solves the problems that the existing electronically controlled hydraulic power steering system is converted into an ordinary hydraulic power steering system when the electric control device fails, which increases the fatigue degree during fast steering and reduces the steering comfort, and also solves the problem of The problem that the electro-hydraulic power steering system cannot often work in the speed range corresponding to high efficiency.

Description

An electric and electric control two-in-one hydraulic power steering system

technical field

The utility model belongs to the technical field of automobile steering, in particular to an electric and electric control two-in-one hydraulic power steering system.

Background technique

The hydraulic power steering system uses the engine to drive the steering oil pump to provide the power source, converts the mechanical energy of the engine rotation into the hydraulic energy of the steering oil, provides steering assistance through the power steering gear, and reduces the steering force exerted by the driver on the steering wheel.

According to different control methods, the electro-hydraulic power steering system can be divided into three types: reaction force control type, flow control type and valve gain control type.

For the reaction force controlled electronically controlled hydraulic power steering system, on the basis of the existing hydraulic power steering system, the electronically controlled hydraulic power steering system is formed by adding a steering power electronic control device and a vehicle speed sensor. As shown in Figure 1, the reaction force controlled electronically controlled hydraulic power steering system mainly consists of a steering wheel 1, a steering column 2, and an integral power steering gear 3 (including steering control valve 4, mechanical steering gear 5, power cylinder 6, oil Pressure reaction chamber 7, reaction plunger 8), steering oil tank 9, steering oil pump 10, steering oil pipe 11, diverter valve 12 and fixed throttle hole 13, solenoid valve 14, steering control unit ECU 15, vehicle speed sensor 16 The main structural feature is that two pairs of counter force plungers are installed at the front end of the steering control rotary valve spool.

On the basis of the hydraulic power steering system, after the reaction force plunger is installed at the front end of the steering control valve spool, the outer ends of the two groups of symmetrically arranged reaction force plungers are subjected to the hydraulic pressure adjusted by the solenoid valve, while the inner ends are pressed against the valve. On the "one" shaped wing plate at the front end of the core, the pressure can form a torque on the valve core. When turning the steering wheel, it is necessary to overcome the resultant torque of the torque of the torsion spring and the torque of the counter force plunger before the relative angular displacement of the valve core and the valve body can be generated to realize steering hydraulic power assistance.

Compared with the mechanical steering system, the advantages of the electro-hydraulic power steering system are numerous: it can reduce driver fatigue, especially when parking and turning; it reduces the impact of road recoil on the steering wheel and improves steering sensitivity; at the same time, it improves safety . However, after the electronic control device fails, the electronically controlled hydraulic power steering system is transformed into a common hydraulic power steering system. If there is no control signal on the solenoid valve, the maximum steering "road feel" will be maintained, making the direction heavy when turning on the spot or at low speed; at the same speed, with the increase of the steering speed, because the ECU controls the average If the current remains unchanged, the average opening of the solenoid valve will also remain unchanged, and the steering force will not decrease with the increase of the steering speed, which will increase the fatigue degree during fast steering, reduce the steering comfort, and cause insufficient power assistance and slow response of fast steering And other shortcomings, so that its use is subject to certain restrictions.

In addition, the electrohydraulic power steering system is based on the hydraulic power steering system. The steering oil pump driven by the engine is changed to the steering oil pump driven by the steering motor. The power battery pack or battery independent of the engine is used to supply power to the steering motor. The controller controls the rotation speed of the steering motor according to the running state of the vehicle (whether the engine is on, the steering speed, and the vehicle speed), so as to improve the energy-saving effect and realize the characteristic that the steering force changes with the vehicle speed and steering speed. The electro-hydraulic power steering technology not only has the characteristics of mature traditional hydraulic power steering technology, large power assistance, reliable operation and good hand feeling, but also has the advantages of high efficiency and easy control of the electric motor; And other parameters can be adjusted by themselves, which is more humanized. Compared with the hydraulic power steering system, it can achieve "light steering at low speeds, enhanced road feeling at high speeds (that is, reduced power assistance) to avoid drifting", and energy saving and high efficiency. However, since the rotation speed range of the steering motor varies greatly, the efficiency varies greatly, so it cannot always work in the rotation speed range corresponding to high efficiency.

Utility model content

The purpose of this utility model is to provide an electric and electronically controlled two-in-one hydraulic power steering system, which is used to solve the fatigue and steering comfort of the existing electric control hydraulic power steering system when the electric control device fails. Lowering the problem.

For solving the problems of the technologies described above, the technical solution of the utility model is:

An electric and electric control two-in-one hydraulic power steering system of the present utility model comprises a steering control unit, a hydraulic power boosting pipeline and a steering oil pump arranged on the hydraulic power boosting pipeline, and a solenoid valve is also arranged on the hydraulic power boosting pipeline. The steering motor drives the steering oil pump, and the steering control unit is connected with the solenoid valve and the steering motor.

Further, the steering system further includes a detection device for detecting a failure of the solenoid valve.

Further, the detection device is a flow sensor installed in the hydraulic booster pipeline.

Further, the detection device is a solenoid valve action detection device, including a travel switch installed on the movement path of the solenoid valve plunger for being triggered by the solenoid valve plunger.

Further, the solenoid valve is a normally open solenoid valve in which the plunger of the solenoid valve is kept in the normally open position by a spring, and the travel switch includes a switch contact, and the switch contact is in contact with the plunger of the solenoid valve in the normally open position.

Further, the switch contact has a closing position for conducting the circuit where the travel switch is located when the solenoid valve plunger is in the normally open position, and an opening position for disconnecting the circuit where the travel switch is located when the solenoid valve plunger is in action.

Further, a support sleeve is arranged inside the spring, and the circuit where the travel switch is located includes a wire arranged on the support sleeve. The upper end of the support sleeve is provided with an inversion edge, and the switch contact is arranged on the lower side of the inversion edge. There is a contact point on the inner turning edge for contacting with the switch contact, and the solenoid valve plunger has a protrusion passing through the inner turning edge and realizing contact connection with the switch contact.

Further, the solenoid valve includes a valve body, and the plunger includes a plunger body that guides and cooperates with the valve body, the plunger body is connected to the protrusion through a transition shoulder, and the spring is used to lift the transition shoulder.

Further, it also includes a steering angular velocity sensor installed on the steering column of the hydraulic power steering system, and the steering control unit is sampled and connected to the steering angular velocity sensor.

The beneficial effects of the utility model:

The electric and electric control two-in-one hydraulic power steering system of the utility model includes two working modes of the electric control mode and the electric mode. Under normal circumstances, the system works in the electronic control mode, enabling the car to turn easily at low speeds and form a strong steering "road feel" at high speeds. When the electronic control mode fails, switch to the electric mode, and the steering motor drives the steering oil pump, and controls the motor speed according to the running state of the vehicle (steering speed, vehicle speed), so as to improve the energy saving effect and realize that the steering force varies with the vehicle speed and steering. change with speed. The utility model solves the problems of increased fatigue and reduced steering comfort when the electric control device fails in the existing electronically controlled hydraulic power steering system.

Description of drawings

Figure 1 is a structural diagram of the reaction force controlled electronically controlled hydraulic power steering system;

Fig. 2 is a structural diagram of the reaction force controlled electric and electric control two-in-one hydraulic power steering system;

Fig. 3 is a schematic diagram of a solenoid valve without a travel switch;

Fig. 4 is a schematic diagram when the solenoid valve with the travel switch added is in the normally open state;

Fig. 5 is a schematic diagram when the hollow plunger of the electromagnetic valve with a travel switch moves downward;

Fig. 6 is the relationship between the calibrated current I of the counterforce controlled electric and electronically controlled hydraulic power steering system, the steering angular velocity υ, and the vehicle speed V;

Fig. 7 is the relationship between the steering motor frequency f calibrated by the reaction force control type electric and electronically controlled hydraulic power steering system, the steering angular velocity υ, and the vehicle speed V;

Figure 8 shows the relationship between the calibrated current I of the flow-controlled electric and electronically controlled hydraulic power steering system, the steering angular velocity υ, and the vehicle speed V.

detailed description

In order to make the purpose, technical solution and advantages of the utility model clearer, the specific implementation of the utility model will be further described in detail below in conjunction with the accompanying drawings.

Generally speaking, on the traditional hydraulic power steering system, the utility model is equipped with a steering angular velocity sensor on the steering column, and the steering control unit ECU adjusts the strength of the steering power according to the speed of the vehicle, and according to the magnitude of the applied steering force, the driver can get a natural At the same time, the steering oil pump driven by the engine is replaced by the steering oil pump driven by the steering motor, and the control function of the steering control unit ECU is expanded to form a new electric and electronically controlled hydraulic power steering system.

The electric and electronically controlled two-in-one hydraulic power steering system, when working normally, the steering motor works in the high-efficiency steering range, realizing the function of electronically controlled hydraulic power steering; using the solenoid valve with a travel switch, the steering control unit ECU can judge Whether the solenoid valve fails; when the solenoid valve fails to realize the electronically controlled hydraulic power steering function, the steering control unit ECU controls the steering motor to work with frequency conversion according to the vehicle speed and steering angular velocity to realize the electrohydraulic power steering function. In this way, the electric and electronically controlled two-in-one hydraulic power steering system can realize "light steering at low speeds, enhanced road feeling (that is, reduced power assistance) and avoid drifting at high speeds" under different working conditions, while saving energy and high efficiency.

As shown in Figures 1 and 2, taking the reaction force control type as an example, on the basis of the reaction force control type electronically controlled hydraulic power steering system, the steering column 2 is provided with a steering angular velocity sensor 17 . During steering, the steering angular velocity sensor 17 converts the steering angular velocity into a corresponding electrical signal and sends it to the steering control unit ECU 15 . A travel switch is added to the solenoid valve 14, and the steering control unit ECU 15 judges whether the solenoid valve fails by detecting the voltage change of the travel switch circuit. Meanwhile, the steering oil pump 10 is driven by the steering motor.

At first, the car works in the working mode of the electronically controlled hydraulic power steering system (referred to as the electronically controlled working mode). The control unit ECU15 adjusts the return flow of hydraulic oil on one side of the reaction plunger under the control of the current signal, thereby controlling the magnitude of the reaction force of the reaction plunger.

When the car stops or the driving speed is low, the steering control unit ECU 15 increases the average current passing through the solenoid valve coil, the average opening of the solenoid valve 14 increases, and the return flow of the shunted hydraulic oil increases, acting on the counterforce plunger The back pressure of 8 is reduced, and only a small steering torque is needed to overcome the resultant torque of the torsion spring torsion and the reaction force plunger when turning, so that the torsion spring of the steering control valve 4 produces torsional deformation to realize steering assist, that is, to achieve low speed. Steer easily.

When the driving speed of the car is high, the steering control unit ECU 15 reduces the average current passing through the solenoid valve coil, the average opening of the solenoid valve 14 decreases, the return flow of the shunted hydraulic oil decreases, and the force acting on the counterforce plunger When the back pressure increases, a larger steering torque is required to overcome the resultant torque of the torsion spring and the counter force plunger (equivalent to increasing the stiffness of the torsion spring), so that the torsion spring of the steering control valve 4 is torsionally deformed to realize steering Power assist, that is, a strong steering "road feel" at high speeds.

Steering control unit ECU function:

1) After the steering control unit ECU 15 receives the vehicle speed signal and the steering angular velocity signal, the average current passing through the control solenoid valve coil (corresponding to the average opening degree of the plunger) is opposite to the growth trend of the vehicle speed and steering angular velocity.

When the car stops or the driving speed is low, the steering control unit ECU 15 increases the average current passing through the solenoid valve coil, the average opening of the plunger of the solenoid valve 14 increases, and the return flow of the shunted hydraulic oil increases, acting on the reaction force The back pressure of the plunger 8 is reduced to realize easy steering at low speeds; when the vehicle is running at a high speed, the steering control unit ECU 15 reduces the average current passing through the solenoid valve coil, and the average opening of the plunger of the solenoid valve 14 decreases , the return flow of the shunted hydraulic oil is reduced, and the back pressure acting on the reaction force plunger 8 is increased, so as to realize high-speed and strong steering "road feel" (that is, increase the steering force).

At the same vehicle speed, with the increase of the steering angular velocity, the average current passing through the solenoid valve coil increases, the average opening degree of the plunger of the solenoid valve 14 increases, and the return flow of hydraulic oil shunted through the solenoid valve 14 increases, acting on the counter force of the rotary valve The back pressure of the plunger 8 is reduced, and only a small steering torque is needed to overcome the resultant torque of the torsion spring torque and the reaction force plunger, so that the torsion spring of the steering control valve 4 is twisted and deformed, and the power steering is realized and the steering force is reduced .

The relationship between the current I to be calibrated, the steering angular velocity υ, and the vehicle speed V is shown in Figure 6. The electromagnetic coil passes through the calibrated current value I, and the steering force F should meet the target value and range specified by the vehicle design.

2) When the vehicle starts to drive or turn, the plunger of the solenoid valve 14 should be opened, the travel switch on the corresponding solenoid valve 14 should change from "on" to "off", and the voltage signal input to the steering control unit ECU 15 should be changed from " High" to "Low". If the steering control unit ECU 15 detects that the voltage signal does not change, it means that the plunger of the solenoid valve 14 is not opened, and the reaction force control function is invalid. At this time, the control function of the steering control unit ECU 15 is switched to the electrohydraulic power assist mode, and the relationship between the frequency f of the steering motor, the steering angular velocity υ, and the vehicle speed V is as follows: when the vehicle stops or the driving speed is low, the ECU controls the steering motor to operate at high frequency; When the driving speed of the car is high, the ECU controls the steering motor to operate at a low frequency, realizing light steering at low speeds and a strong steering "road feel" at high speeds.

The relationship between the steering motor frequency f to be calibrated, the steering angular velocity υ, and the vehicle speed V is shown in Figure 7. The steering control unit ECU controls the steering motor to run at the calibrated frequency, and the steering force F should meet the target value and range specified by the vehicle design.

The solenoid valve 14 is provided with a travel switch, and the steering control unit ECU 15 judges whether the solenoid valve fails, that is, the steering control unit ECU 15 detects the voltage change of the travel switch circuit. When the steering control unit ECU 15 controls the plunger opening of the solenoid valve 14 to change, but the "high" voltage signal can still be detected, it indicates that the solenoid valve is invalid, and the system cannot work in the electronic control mode. At this time, it needs to switch to electric control mode. The working mode of the hydraulic power steering system (referred to as the electric working mode).

In the electric working mode, the steering oil pump 10 is driven by the steering motor, and the power battery pack or storage battery independent of the engine is used to supply power to the steering motor. At the same time, the steering control unit ECU 15 controls the steering according to the running state of the vehicle (steering speed, vehicle speed). The rotation speed of the motor improves the energy-saving effect, and at the same time realizes the characteristic that the steering force changes with the vehicle speed and steering speed. When the vehicle speed is low, the steering motor operates at high frequency, the power assist effect is strong, and the steering is light; as the vehicle speed increases, the frequency of the steering motor decreases linearly, the power assist effect decreases, and the high-speed steering "road feel" is enhanced. When the vehicle speed is constant, the smaller the steering angular velocity, the lower the frequency of the steering motor, and the corresponding decrease in the power steering effect; the larger the steering angular velocity, the increase in the frequency of the steering motor, and the corresponding increase in the power steering effect.

Fig. 3 is the electromagnetic valve that does not increase travel switch, and electromagnetic valve comprises valve body 18, is arranged on the hollow plunger 19 in valve body 18, and is arranged on the electromagnetic coil 20 outside valve body 18, and hollow plunger 19 includes and valve body 18 guides a mating plunger body 21 and projection 22 (with contacts). The plunger body 21 is connected to the protrusion 22 through a transition shoulder 23 , and a spring 24 is used to push up the transition shoulder 23 . The solenoid valve maintains the hollow plunger 19 in a normally open state through the spring 24, and is a normally open solenoid valve. The hollow plunger 19 is provided with a small valve port 25 and a large valve port 26 matched with the valve body 18 . Through the reciprocating movement of the hollow plunger 19 up and down, the opening of the solenoid valve changes, that is, the flow rate from the small valve port to the large valve port changes, thereby controlling the hydraulic power steering.

Figure 4 shows a solenoid valve with a travel switch added, and a travel switch is added on the basis of Figure 3 . The travel switch includes a switch contact 27. Under normal circumstances, the switch contact 27 is in contact with the contact of the protrusion 22 of the hollow plunger 19 of the solenoid valve in the normally open position. The switch contact has a closing position, which is used to conduct the circuit where the travel switch is located when the hollow plunger 19 of the solenoid valve is in the normally open position; it also has an opening position, which is used to disconnect when the hollow plunger 19 of the solenoid valve is in action. The circuit where the limit switch is located. A support sleeve 28 is arranged inside the spring 24 , and the circuit where the travel switch is located includes a wire 29 arranged in the support sleeve 28 , and the support sleeve 28 is used to support the wire 29 . The upper end of the support sleeve 28 is provided with an inversion edge, the switch contact 27 of the travel switch is arranged on the lower side of the inversion edge, and the wire 29 has a contact point for contacting the switch contact 27 on the inversion edge, and the solenoid valve The protrusion 22 of the hollow plunger passes through the inversion edge and is connected with the switch contact 27 through the contact. The circuit where the travel switch is located also includes a wire 30 and a wire 31 arranged outside the solenoid valve body 18, the wire 31 is connected to the positive pole of the ECU output power supply, the wire 30 is grounded, and a diode 32 is arranged in the circuit, and the anode of the diode 32 is connected to the ground .

In the state shown in Figure 4, the circuit where the limit switch is located is in the conduction state. At this time, the ECU collects the voltage signal and can detect "high" voltage. When the solenoid valve is given an action signal and the hollow plunger moves downward, the protrusion 22 of the hollow plunger will drive the contact (contacting with the switch contact 27 of the travel switch) downward, thereby disconnecting the circuit where the travel switch is located. When the voltage signal is collected by the ECU, the voltage signal is "low", as shown in Figure 5. If the action signal is given to the solenoid valve, when the voltage signal is collected through the ECU, the "high" voltage signal can still be collected, which means that the solenoid valve is invalid.

In this embodiment, as a preferred implementation manner, the steering control unit ECU judges whether the solenoid valve fails according to the solenoid valve with travel switch. If it is judged that the solenoid valve fails, that is, the car cannot work in the electronic control mode to realize the hydraulic power steering function, the car will switch to the electric working mode, and the steering motor will drive the steering oil pump, and the steering control unit ECU will control the steering according to the vehicle speed and steering angular velocity The motor works with frequency conversion to realize the function of electro-hydraulic power steering. As another implementation manner, a flow sensor may be set on the hydraulic pipeline to determine whether the solenoid valve is valid. For example, if the steering control unit ECU controls the opening of the solenoid valve to decrease, but the flow in the oil passage remains unchanged or even increases, it also indicates that the solenoid valve is invalid. At this time, the electric control mode is also switched to the electric mode to realize steering.

In addition, the different ECU functions of flow control type and valve gain type electro-hydraulic assist type are introduced.

According to different structural principles, the flow control type and valve gain control type are different from the reaction force control type. After receiving the vehicle speed signal and steering angular velocity signal, the steering control unit ECU controls the average current passing through the solenoid valve coil (corresponding to the average opening degree of the plunger) with the same growth trend as the vehicle speed and steering angular velocity.

When the car stops or the driving speed is low, the steering control unit ECU reduces the average current passing through the solenoid valve coil, the average opening of the solenoid valve plunger decreases, the return flow of bypass hydraulic oil decreases, and the steering power increases to achieve Light steering at low speeds; when the car is running at high speeds, the steering control unit ECU increases the average current through the solenoid valve coil, increases the average opening of the solenoid valve, increases the return flow of bypass hydraulic oil, and reduces the power steering , to achieve a strong high-speed steering "road feel" (that is, to increase steering force).

At the same vehicle speed, with the increase of the steering angular velocity, the average current passing through the solenoid valve coil decreases, the average opening degree of the solenoid valve plunger decreases, the return flow of hydraulic oil shunted through the solenoid valve bypass decreases, and the steering power gradually increases, realizing Reduction of steering assistance.

The relationship between the current I to be calibrated, the steering angular velocity υ, and the vehicle speed V is shown in Figure 8. The electromagnetic coil passes through the calibrated current value I, and the steering force F should meet the target value and range specified by the vehicle design.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions of the present utility model will be obvious to those skilled in the art after reading the above content. Therefore, the protection scope of the present utility model should be defined by the appended claims.

Claims (9)

1. a kind of electronic and automatically controlled two-in-one hydraulic power-assist steering system, including turning control cell, hydraulic booster pipeline and set Put the steering pump on hydraulic booster pipeline, it is characterised in that be additionally provided with magnetic valve on the hydraulic booster pipeline, turn to Motor drives the steering pump, and the turning control cell is connected with the magnetic valve, steering motor.

2. according to claim 1 electronic and automatically controlled two-in-one hydraulic power-assist steering system, it is characterised in that the steering System also includes being used for the detection means for detecting the solenoid valve failure.

3. according to claim 2 electronic and automatically controlled two-in-one hydraulic power-assist steering system, it is characterised in that the detection Device is the flow sensor being installed in the hydraulic booster pipeline.

4. according to claim 2 electronic and automatically controlled two-in-one hydraulic power-assist steering system, it is characterised in that the detection Device is magnetic valve action detection device, including is used on magnet plunger motion path by magnet plunger triggering Travel switch.

5. according to claim 4 electronic and automatically controlled two-in-one hydraulic power-assist steering system, it is characterised in that the electromagnetism Valve is the normally open type magnetic valve that magnet plunger is held in normally open position by spring, and the travel switch includes switch and touched Head, switch contact contact with the magnet plunger of normally open position.

6. according to claim 5 electronic and automatically controlled two-in-one hydraulic power-assist steering system, it is characterised in that switch contact With the closing position in loop where the conducting travel switch when magnet plunger is in normally open position and in magnet plunger The sub-gate position in loop where disconnecting travel switch during action.

7. according to claim 6 electronic and automatically controlled two-in-one hydraulic power-assist steering system, it is characterised in that set in spring Supporting sleeve is equipped with, loop where travel switch includes the wire being arranged on the supporting sleeve, and supporting sleeve upper end is set There is turn edge, switch contact is arranged at the downside of turn edge, and wire has to be used for and the switch in the turn edge The contact of contact, magnet plunger have through turn edge and realize the projection for contacting and being connected with the switch contact.

8. according to claim 7 electronic and automatically controlled two-in-one hydraulic power-assist steering system, it is characterised in that the electromagnetism Valve includes valve body, and the plunger includes being oriented to the piston body coordinated with valve body, and the piston body passes through transition shoulder and projection It is connected, spring is used to jack up transition shoulder.

9. according to claim 1 electronic and automatically controlled two-in-one hydraulic power-assist steering system, it is characterised in that also include peace Steering angular velocity sensor on steering column loaded on hydraulic power-assist steering system, the turning control cell sampling connection institute State steering angular velocity sensor.