Electric and hydraulic hybrid power-assisted steering system and crane

Abstract

The invention discloses an electric and hydraulic hybrid power-assisted steering system which comprises hydraulic power-assisted steering and electric power-assisted steering, the hydraulic power-assisted steering is applied to front axle mechanical steering, and the electric power-assisted steering is applied to middle and rear axle steering; the electric power steering system comprises a steering angle sensor, an electric power steering control module, an electric cylinder controller, an electric cylinder and axle wheels which are connected in sequence, the electric power steering control module is connected with the steering switch, and the electric power steering control module and the electric cylinder controller are both connected with the power source; steering of a front axle is achieved through hydraulic power-assisted steering, steering of other axles except the front axle is achieved through electric power-assisted steering, and therefore multiple steering modes are achieved. According to the multi-axle multi-mode steering system, an original hydraulic power-assisted oil cylinder and a steering neutral-position locking oil cylinder are replaced by the electric cylinder, and original various electro-hydraulic proportional valves, steering control locking valves and the like are replaced by electric control programs to achieve multi-axle multi-mode steering; the device has the characteristics of simplicity in arrangement, light weight, low cost, safety, environment friendliness and capability of meeting the electric development trend.

Description

Technical Field

[0001] The present invention relates to the field of cranes, and particularly to an electric and hydraulic hybrid power steering system and a crane. Background Art

[0002] At present, the power steering of heavy construction machinery vehicles such as cranes is mainly mechanical hydraulic power steering, that is, mechanical hydraulic power steering is realized through a steering mechanism, a power steering gear, a steering assist cylinder, etc. A steering oil pump provides hydraulic oil and oil pressure. The hydraulic oil flows to the power steering gear, and through the steering gear, the assist oil circuit is distributed and high and low pressure cavities are established. The hydraulic oil is distributed to different circuit steering cylinders. Through the telescopic action of the steering cylinders, assistance is brought to the steering mechanism, reducing the steering operation force. The steering cylinders can also be arranged on the trapezoidal arms of the axle, and the same can bring steering assistance.

[0003] The front axle realizes mechanical hydraulic power steering through a steering mechanism, a power steering gear, a steering cylinder, etc. The rear axle steering realizes hydraulic power steering through a steering proportional valve, a steering control valve, a steering cylinder, etc., so as to realize the multi-axle steering of the whole machine. This kind of power steering method is the most commonly used steering assist form in the steering systems of construction machinery vehicles at present.

[0004] However, the fully mechanical hydraulic power steering has the following problems: 1. The steering valve and pipelines are complex: At present, construction machinery vehicles such as cranes will continuously increase the vehicle weight in order to achieve large lifting weights and excellent performance. To meet the vehicle weight matching, double axles or multiple axles are used for load bearing or steering. This makes the number of steering valves increase during multi-axle steering, and the pipelines are numerous and long. Limited space leads to complex layout and increased weight. 2. As a medium for power transmission, hydraulic oil is easily affected by environmental temperature and pollutants, resulting in problems such as loud noise and heavy steering. The steering hydraulic oil is prone to leakage, increasing the maintenance cost and polluting the environment. 3. With the development trend of new energy, this power steering method will be gradually replaced, and electric power steering will become the future development trend of power steering. The fully mechanical hydraulic power steering cannot meet the future electrified and intelligent driving requirements.

[0005] In response to this, hybrid steering systems have been gradually developed. For example, the patent document CN116968805A discloses "a steering axle, a steering control system and a crane". An electric motor is added to the kingpin of the rear axle of this patent, so that the electric motor is directly connected to the kingpin, and the steering angle of the wheel is controlled by the rotation of the electric motor. The steering assist is still realized in a hydraulic form.

[0006] However, in the prior art, by adding an electric motor to the kingpin of the rear axle to control the steering angle, and the steering assist is still realized in a hydraulic form, which makes the system more complex and cannot solve the problems of too many steering valves in the steering system, numerous and long pipelines, complex layout due to limited space, and increased weight.

[0007] Therefore, it is necessary to specifically develop a new type of electric and hydraulic hybrid steering assist system and crane to overcome problems such as a large number of steering valves, long and numerous pipelines in the steering system, complex layout due to space constraints, and increased weight. Summary of the Invention

[0008] Object of the Invention: Aiming at the deficiencies and defects of the prior art, the present invention provides an electric and hydraulic hybrid steering assist system and a crane. By replacing the original hydraulic assist oil cylinder and steering neutral locking oil cylinder with an electric cylinder, and replacing the original various electro-hydraulic proportional valves, steering control locking valves, etc. with an electronic control program, multi-bridge multi-mode steering is realized; it has the characteristics of simple layout, small weight, low cost, safety and environmental protection, and meets the development trend of electrification.

[0009] Technical Solution: An electric and hydraulic hybrid steering assist system of the present invention is characterized in that it includes hydraulic steering assist and electric steering assist. The hydraulic steering assist is applied to the mechanical steering of the front axle, and the electric steering assist is applied to the steering of the middle and rear axles; the electric steering assist includes a steering angle sensor, an electric steering control module, an electric cylinder controller, an electric cylinder and a vehicle axle wheel connected in sequence. Among them, the electric steering control module is connected to the steering switch, and both the electric steering control module and the electric cylinder controller are connected to the power supply; the hydraulic assist steering realizes the steering of the front axle, and the electric assist steering realizes the steering of other multiple axles except the front axle, thereby realizing various steering modes.

[0010] Among them, the hydraulic steering assist is provided with a power steering gear, a steering mechanism, a steering assist oil cylinder, and a steering pump.

[0011] Among them, the steering angle sensor is located on the steering wheel or the kingpin of the first axle to obtain the steering angle and direction signal. The steering angle sensor transmits the signal to the electric steering control module, and the electric steering control module can receive both the signal of the steering angle sensor and the vehicle speed signal and the steering switch command signal of the whole machine.

[0012] Among them, the electric steering control module judges the telescopic and displacement stroke of the electric cylinder according to the value and direction of the steering angle sensor. The electric cylinder controller controls the telescopic and displacement stroke of the electric cylinder according to the displacement stroke and telescopic direction input by the electric steering control module.

[0013] Among them, the number of the electric cylinders and their controllers increases or decreases according to the steering assist requirements, and the electric cylinders and their controllers correspond one by one.

[0014] Among them, the electric cylinder is located on the trapezoidal arm of the vehicle axle or the upper steering knuckle arm connected to the kingpin of the vehicle axle. The electric cylinder is telescoped under the manipulation of its controller, driving the rotation of the trapezoidal arm or the upper steering knuckle arm of the vehicle axle, thereby realizing the left and right rotation of the wheel. The telescopic displacement stroke of the electric cylinder determines the angle of the left and right rotation of the wheel.

[0015] Among them, the rear axle includes wheels, a steering axle, an electric cylinder assembly, a tie rod, and steering trapezoid arms.

[0016] Among them, the steering axle is located between the wheels on both sides. The tie rod is connected to the steering trapezoid arms on both sides, and the steering axle is connected to the electric cylinder assembly.

[0017] During use:

[0018] 1) When the electric power steering control module and the electric cylinder control module are not powered on, the electric cylinder is in the middle position braking state.

[0019] 2) When both the electric power steering control module and the electric cylinder control module are powered on, the electric power steering control module detects whether it receives a steering switch command. If there is no steering switch command, the electric cylinder is in the middle position braking state. If there is a command, it then detects the vehicle speed signal of the whole machine. If the vehicle speed is greater than the preset vehicle speed value, the electric power steering control module gives a command signal to the electric cylinder controller, making the electric cylinder corresponding to this electric cylinder controller be in the middle position braking state, achieving the middle position locking state of a certain axle or multiple axles. If the vehicle speed is less than the preset vehicle speed value, the electric power steering control module continues to detect the signal of the angle sensor, processes the angle sensor signal through the processor inside the electric power steering control module, calculates the displacement stroke and movement direction of the electric cylinder, and transmits these command data to the electric cylinder controller. The electric cylinder controller drives the electric cylinder to make corresponding telescopic movements, and the movement of the electric cylinder drives the wheels to meet the steering requirements.

[0020] 3) The electric power steering control module can issue control commands to multiple axles simultaneously according to different steering control mode requirements, realizing multiple steering modes of multiple axles.

[0021] A crane, characterized in that: it uses the electric and hydraulic hybrid steering assist system of the present invention.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: The present invention replaces the original hydraulic assist oil cylinder and the steering middle position locking oil cylinder with an electric cylinder, and replaces the original multiple electro-hydraulic proportional valves, steering control locking valves, etc. through an electronic control program to achieve multi-axle multi-mode steering; it has the characteristics of simple layout, small weight, low cost, safety, environmental protection, and meeting the development trend of electrification. The present invention solves the following problems: 1. When multiple axles cooperate in steering, there are many components involved in the steering valve, steering oil cylinder, steering middle position locking oil cylinder, and steering pipeline, and the layout is complex and difficult; 2. The problems of high noise and heavy steering caused by the influence of environmental temperature on hydraulic oil, and the problems of high maintenance cost and environmental pollution caused by hydraulic oil leakage; 3. Meeting the development trend of electrification. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of a hydraulic steering assist system of a crane in the prior art;

[0024] Figure 2 This is a schematic structural diagram of the electric and hydraulic hybrid steering assist system of the present invention;

[0025] Figure 3 This is a block diagram of the electric power steering control structure of the present invention;

[0026] Figure 4 This is a layout schematic diagram of the electric power-assisted rear axle of the present invention;

[0027] In the figure, 1 is a wheel; 2 is a steering axle; 3 is an electric cylinder assembly; 4 is a tie rod; 5 is a steering trapezoid arm. Specific embodiments

[0028] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0029] The electric and hydraulic hybrid steering assist system of the present invention includes hydraulic steering assist and electric steering assist. The hydraulic steering assist is applied to the front axle mechanical steering, and the electric steering assist is applied to the middle and rear axle steering; the electric steering assist includes a steering angle sensor, an electric steering control module, an electric cylinder controller, an electric cylinder and a vehicle axle wheel connected in sequence. Among them, the electric steering control module is connected to the steering switch, and both the electric steering control module and the electric cylinder controller are connected to the power supply; the hydraulic power steering realizes the steering of the front axle, and the electric power steering realizes the steering of other multiple axles except the front axle, so as to realize multiple steering modes.

[0030] The hydraulic steering assist of the present invention is provided with a power steering gear, a steering mechanism, a steering assist oil cylinder, and a steering pump. The steering angle sensor is located on the steering wheel or the kingpin of one axle to obtain the steering angle and direction signals. The steering angle sensor transmits the signals to the electric steering control module. The electric steering control module can receive both the steering angle sensor signals and the vehicle speed signals and steering switch command signals of the whole machine. The electric steering control module judges the telescopic and displacement strokes of the electric cylinder according to the value and direction of the steering angle sensor. The electric cylinder controller controls the telescopic and displacement strokes of the electric cylinder according to the displacement stroke and telescopic direction input by the electric steering control module. The number of the electric cylinders and their controllers increases or decreases according to the steering assist requirements, and the electric cylinders and their controllers are in one-to-one correspondence. The electric cylinder is located on the trapezoid arm of the vehicle axle or on the upper steering knuckle arm connected to the kingpin of the vehicle axle. The electric cylinder is telescoped under the manipulation of its controller, driving the rotation of the trapezoid arm of the vehicle axle or the upper steering knuckle arm, thereby realizing the left and right rotation of the wheel. The telescopic displacement stroke of the electric cylinder determines the angle of the left and right rotation of the wheel.

[0031] The rear axle of the present invention includes a wheel 1, a steering axle 2, an electric cylinder assembly 3, a tie rod 4 and a steering trapezoid arm 5. The steering axle 2 is located between the wheels 1 on both sides. The tie rod 4 is connected to the steering trapezoid arms 5 on both sides, and the steering axle 2 is connected to the electric cylinder assembly 3.

[0032] When the electric and hydraulic hybrid steering assist system of the present invention is in use:

[0033] 1) When the electric steering control module and the electric cylinder control module are not powered on, the electric cylinder is in the neutral braking state;

[0034] 2) When both the electric steering control module and the electric cylinder control module are powered on, the electric steering control module detects whether it receives a steering switch command. If there is no steering switch command, the electric cylinder is in the neutral braking state. If there is a command, it then detects the vehicle speed signal of the whole machine. If the vehicle speed is greater than the preset vehicle speed value, the electric steering control module gives a command signal to the electric cylinder controller, making the electric cylinder corresponding to this electric cylinder controller be in the neutral braking state, realizing the neutral locking state of a certain axle or multiple axles; if the vehicle speed is less than the preset vehicle speed value, the electric steering control module continues to detect the signal of the angle sensor, processes the signal of the angle sensor through the processor inside the electric steering control module, calculates the displacement stroke and movement direction of the electric cylinder, and transmits these command data to the electric cylinder controller. The electric cylinder controller drives the electric cylinder to make corresponding telescopic movements, and the movement of the electric cylinder drives the wheels to meet the steering requirements;

[0035] 3) The electric steering control module can issue control commands to multiple axles simultaneously according to the requirements of different steering control modes, realizing multiple steering modes of multiple axles.

[0036] In the electric power steering assist form of the present invention, the processor inside the electric steering control module calculates the telescopic displacement of the electric cylinder according to the rotation angle and rotation direction of the steering wheel; the electric cylinder itself has a neutral brake. When the electric cylinder is not powered on, all electric cylinders are in the neutral braking state; when the vehicle speed signal received by the electric steering control module is greater than a certain predetermined vehicle speed value, the electric steering control module controls the electric cylinders of a certain axle or multiple axles to be in the neutral braking state; when the steering switch signal is off or there is no steering switch signal, all electric cylinders are in the neutral braking state; the power supply is connected to the electric steering control module, the electric cylinder controller, etc., and provides electric energy for the movement of the electric cylinder; the electric cylinder is equipped with limit switches, and each steering axle has a left-turn limit switch and a right-turn limit switch respectively. The limit switch judges the braking of the electric cylinder by judging whether the telescopic displacement of the electric cylinder reaches the preset telescopic displacement. When the telescopic displacement of the electric cylinder reaches the preset telescopic displacement, the electric cylinder controller will control this electric cylinder to stop further telescopic movement; the axle is also equipped with an angle limit bolt. When the limit switch of the electric cylinder judges that the telescopic displacement of the electric cylinder reaches the preset maximum telescopic displacement and the electric cylinder stops telescoping, the length of the axle limit bolt is adjusted to realize the maximum angle mechanical limit of the axle, protecting the electric cylinder to a certain extent; the steering cylinder can be arranged on the axle trapezoidal arm or in the steering mechanism.

[0037] One or more electric cylinders can be arranged on each electric power-assisted rear axle of the present invention; the controller of the electric cylinder is integrated on the electric cylinder or separately arranged outside; the electric cylinder can move according to the rotation angle value and direction input by the rotation angle sensor, and can also actively control the telescopic displacement action according to specific instructions of the electric steering control module.

[0038] In the electric and hydraulic hybrid power-assisted form of the present invention, the rotation angle sensor can also be arranged on the mechanical axle and multiple electric axles at the same time to obtain the rotation angle of the mechanical axle and the rotation angles of the electric axles under different steering modes at the same time. Hydraulic power assistance is mainly applied to the front axle, and electric power assistance is mainly applied to the middle and rear axles. Hydraulic power assistance realizes power assistance through the steering cylinder and the power steering gear, and electric power assistance realizes steering assistance through the electric cylinder and the electric steering control module, etc. The mechanical hydraulic power assistance of the front axle is not restricted by the electric steering assistance of the middle and rear axles, and at the same time, the electric steering of the middle and rear axles can cooperate with the mechanical hydraulic steering of the front axle to realize multiple steering modes.

Claims

1. An electric and hydraulic hybrid power steering system, characterized in that: It includes hydraulic power steering and electric power steering. The hydraulic power steering is applied to the mechanical steering of the front axle, and the electric power steering is applied to the steering of the middle and rear axles. The electric power steering includes an angle sensor, an electric steering control module, an electric cylinder controller, an electric cylinder and vehicle axles and wheels connected in sequence. Among them, the electric steering control module is connected to the steering switch, and both the electric steering control module and the electric cylinder controller are connected to the power supply. The hydraulic power steering realizes the steering of the front axle, and the electric power steering realizes the steering of multiple axles other than the front axle, thus realizing multiple steering modes.

2. The electro-hydraulic hybrid power steering system according to claim 1, wherein: The hydraulic power steering is provided with a power steering gear, a steering mechanism, a steering assist cylinder and a steering pump.

3. The electro-hydraulic hybrid power steering system according to claim 1, wherein: The angle sensor is located on the steering wheel or the kingpin of one axle to obtain the steering angle and direction signals. The angle sensor transmits the signals to the electric steering control module. The electric steering control module can receive both the angle sensor signals, the vehicle speed signal of the whole machine and the steering switch command signal.

4. The electric and hydraulic hybrid power steering assist system according to claim 3, wherein: The electric steering control module judges the telescopic and displacement stroke of the electric cylinder according to the value and direction of the angle sensor. The electric cylinder controller controls the telescopic and displacement stroke of the electric cylinder according to the displacement stroke and telescopic direction input by the electric steering control module.

5. The electric and hydraulic hybrid steering assist system according to claim 4, wherein: The number of the electric cylinders and their controllers increases or decreases according to the steering assist requirements, and the electric cylinders and their controllers correspond to each other one by one.

6. The electro-hydraulic hybrid power steering assist system according to claim 5, wherein: The electric cylinder is located on the trapezoidal arm of the axle or the upper steering knuckle arm connected to the kingpin of the axle. The electric cylinder is telescoped under the manipulation of its controller, driving the rotation of the trapezoidal arm of the axle or the upper steering knuckle arm, thus realizing the left and right rotation of the wheels. The telescopic displacement stroke of the electric cylinder determines the angle of the left and right rotation of the wheels.

7. The electro-hydraulic hybrid power steering system according to claim 5, characterized in that: The rear axle includes wheels, a steering axle, an electric cylinder assembly, a tie rod and a steering trapezoidal arm.

8. The electric and hydraulic hybrid power steering assist system according to claim 7, characterized in that: The steering axle is located between the wheels on both sides. The tie rod is connected to the steering trapezoidal arms on both sides, and the steering axle is connected to the electric cylinder assembly.

9. The electric and hydraulic hybrid power steering assist system according to any one of claims 1-8, characterized in that: During use: 1) When the electric steering control module and the electric cylinder control module are not powered on, the electric cylinder is in the middle position braking state. 2) When both the electric steering control module and the electric cylinder control module are powered on, the electric steering control module detects whether it receives a steering switch command. If there is no steering switch command, the electric cylinder is in the middle position braking state. If there is, it detects the vehicle speed signal of the whole machine. If the vehicle speed is greater than the preset vehicle speed value, the electric steering control module gives a command signal to the electric cylinder controller, making the electric cylinder corresponding to the electric cylinder controller in the middle position braking state, realizing the middle position locking state of a certain axle or multiple axles. If the vehicle speed is less than the preset vehicle speed value, the electric steering control module continues to detect the angle sensor signal, processes the angle sensor signal through the processor inside the electric steering control module, calculates the displacement stroke and movement direction of the electric cylinder, and transmits these command data to the electric cylinder controller. The electric cylinder controller drives the electric cylinder to make corresponding telescopic movements, and the electric cylinder action drives the wheels to realize the steering demand. 3) The electric steering control module can issue control commands to multiple axles simultaneously according to different steering control mode requirements, realizing multiple steering modes of multiple axles.

10. A crane, characterized in that: Use the electric and hydraulic hybrid power steering system according to any one of claims 1-8.

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