Electric power steering system and crane thereof

Abstract

The invention discloses an electric power-assisted steering system and a crane thereof. The electric power-assisted steering system comprises a steering angle sensor, an electric steering control module, an electric cylinder controller, an electric cylinder, wheels and a steering axle which are connected in sequence, the electric steering control module is connected with the steering switch, the electric steering control module and the electric cylinder controller are both connected with the power source, and the power source provides electric energy for movement of the electric cylinder. The electric cylinder is used for replacing an existing hydraulic power-assisted oil cylinder, and an electric control program is used for replacing existing complex rod system mechanism connection; the structure is simplified, hydraulic oil is prevented from being used, and the electric development requirement is met.

Description

Technical Field

[0001] The invention relates to the field of cranes, and in particular to an electric power steering system and a crane thereof. Background Art

[0002] At present, the power steering of heavy engineering vehicles such as cranes is mainly mechanical hydraulic power steering, that is, mechanical hydraulic power steering is achieved through steering mechanism, power steering gear and power steering cylinder, etc. With the development trend of new energy, this power steering method will gradually be replaced, and electric power steering will become the development trend of power steering in the future.

[0003] The traditional mechanical hydraulic power steering of construction machinery vehicles is affected by the ambient temperature, hydraulic oil medium, etc., which will cause problems such as running noise and heavy steering. By using electric control, the entire steering power steering system is not affected by the ambient temperature and the purity of the hydraulic oil medium, making the entire steering power steering low in running noise and easy to maintain.

[0004] The steering power system of the prior art, such as the patented steering system and crane CN201420468447.7, mainly realizes the steering and hydraulic power assistance of the vehicle through the steering mechanism, power steering gear and steering power cylinder. The steering oil pump provides hydraulic oil and oil pressure, and the hydraulic oil flows to the power steering gear. The steering gear distributes the power oil circuit and establishes high and low pressure cavities, and distributes the hydraulic oil to steering cylinders of different circuits. Through the telescopic action of the steering cylinder, the steering mechanism is powered and the steering control force is reduced. The steering cylinder can also be arranged on the axle trapezoidal arm, which can also provide steering power. This type of power steering method has a simple structure, convenient operation and control, and a mature and reliable principle. It is the most commonly used form of steering power assistance in the steering system of engineering machinery vehicles.

[0005] However, the existing technology has the following problems: 1) The structure is complex. Currently, cranes and other engineering machinery vehicles use double or multiple bridges for load bearing or steering. This requires the design of complex connections for the steering mechanism rod system during multi-bridge steering to achieve multi-bridge mechanical steering, which will bring about problems such as complex steering mechanism design, increased rod system, and increased weight. 2) Hydraulic oil, as a medium for power transmission, is easily affected by ambient temperature and pollutants, causing problems such as loud noise and heavy steering. Steering hydraulic oil is prone to leakage, increasing maintenance costs. 3) Unmanned driving and intelligent assisted driving have become a trend, and the existing mechanical hydraulic power steering cannot meet the needs of electrified and intelligent driving.

[0006] Therefore, it is necessary to develop a new type of electric power steering system to overcome the above problems. Summary of the invention

[0007] Purpose of the invention: In view of the shortcomings and defects of the prior art, the present invention provides an electric power steering system and a crane thereof, which replaces the existing hydraulic power steering cylinder with an electric cylinder and replaces the existing complex rod system connection with an electronic control program; simplifies the structure, avoids the use of hydraulic oil, and meets the needs of electrification development.

[0008] Technical solution: An electric steering power-assist system of the present invention is characterized in that it includes a steering angle sensor, an electric steering control module, an electric cylinder controller, an electric cylinder, a wheel and a steering axle connected in sequence; the electric steering control module is connected to a steering switch, and the electric steering control module and the electric cylinder controller are both connected to a power supply, which provides electrical energy for the movement of the electric cylinder.

[0009] Among them, the steering angle sensor obtains the steering wheel or wheel rotation angle and rotation direction; the electric steering control module receives the vehicle speed signal and the steering switch signal, and receives the steering wheel rotation angle and rotation direction signal of the steering angle sensor; the electric cylinder controller receives the steering instruction of the electric steering control module to control the electric cylinder; one end of the electric cylinder is fixed to the steering axle housing, and the other end is fixed to the steering trapezoidal knuckle arm, and can also be fixed to the steering knuckle arm connected to the steering kingpin; the electric steering control module gives the electric cylinder controller corresponding instructions to drive the electric cylinder to move, drive the wheel to rotate to realize the steering function.

[0010] Among them, the electric steering control module, electric cylinder controller, and electric cylinder constitute an electric cylinder assembly, the steering trapezoidal knuckle arm is located on the side of the wheel, and the steering trapezoidal knuckle arms on both sides are connected by a transverse tie rod.

[0011] 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.

[0012] When the vehicle speed signal received by the electric steering control module is greater than a predetermined vehicle speed value, the electric steering control module controls the electric cylinders of a certain bridge or multiple bridges to be in a neutral braking state.

[0013] Wherein, the electric cylinder is provided with a neutral brake, and when the electric cylinder is not powered, all the electric cylinders are in a neutral braking state.

[0014] Wherein, when the steering switch signal is off or there is no steering switch signal, all electric cylinders are in a neutral braking state.

[0015] Among them, the electric cylinder is provided with a limit switch, and each steering axle has a left-turn limit switch and a right-turn limit switch respectively. The limit switch judges whether the telescopic displacement of the electric cylinder reaches a preset telescopic displacement, thereby judging the braking of the electric cylinder. When the telescopic displacement of the electric cylinder reaches the preset telescopic displacement, the electric cylinder controller will control the electric cylinder to stop the telescopic movement.

[0016] Among them, the axle is provided with an angle limit bolt. When the limit switch of the electric cylinder determines that the telescopic displacement of the electric cylinder has reached the preset maximum telescopic displacement and the electric cylinder no longer telescopes, the length of the axle limit bolt is adjusted to enable the axle to achieve the maximum angle mechanical limit, thereby protecting the electric cylinder to a certain extent.

[0017] A crane using the electric power steering system of the present invention.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the present invention replaces the existing hydraulic power cylinder with an electric cylinder, and replaces the existing complex rod system connection with an electronic control program; simplifies the structure, avoids the use of hydraulic oil, and meets the needs of electrification development. The present invention solves the problems of the existing steering power system with complex layout and heavy weight of the rod system; solves the problems of high noise and heavy steering caused by the influence of ambient temperature on hydraulic oil, avoids leakage of hydraulic oil, and has low maintenance costs; meets the development trend of electrification, and supports unmanned driving and intelligent assisted driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the control structure of the present invention;

[0020] Figure 2 It is a structural schematic diagram of the present invention;

[0021] In the figure, 1 is a wheel; 2 is a steering axle; 3 is an electric cylinder assembly; 4 is a tie rod; and 5 is a steering trapezoidal arm. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0023] The electric steering assist system of the present invention comprises a rotation angle sensor, an electric steering control module, an electric cylinder controller, an electric cylinder, a wheel 1 and a steering axle 2 connected in sequence; the electric steering control module is connected to the steering switch, and the electric steering control module and the electric cylinder controller are both connected to the power supply, which provides electric energy for the movement of the electric cylinder. Among them, the rotation angle sensor obtains the rotation angle and rotation direction of the steering wheel or wheel 1; the electric steering control module receives the vehicle speed signal and the steering switch signal, and receives the steering wheel rotation angle and rotation direction signal of the rotation angle sensor; the electric cylinder controller receives the steering instruction of the electric steering control module to control the electric cylinder; one end of the electric cylinder is fixed to the axle housing of the steering axle 2, and the other end is fixed to the steering trapezoidal knuckle arm 5, and can also be fixed to the steering knuckle arm connected to the steering kingpin; the electric steering control module gives the electric cylinder controller corresponding instructions to drive the electric cylinder to move, driving the wheel 1 to rotate to realize the steering function. The electric steering control module, the electric cylinder controller, and the electric cylinder form an electric cylinder assembly 3, the steering trapezoidal knuckle arm 5 is located on the side of the wheel 1, and the steering trapezoidal knuckle arms 5 on both sides are connected by a tie rod 4.

[0024] The processor inside the electric steering control module of the present invention calculates the telescopic displacement of the electric cylinder according to the rotation angle and rotation direction of the steering wheel. When the vehicle speed signal received by the electric steering control module is greater than a predetermined vehicle speed value, the electric steering control module controls the electric cylinders of a certain bridge or multiple bridges to be in a neutral braking state. The electric cylinder is provided with a neutral brake. When the electric cylinder is not powered, all electric cylinders are in a neutral braking state. When the steering switch signal is off or there is no steering switch signal, all electric cylinders are in a neutral braking state. The electric cylinder is provided with a limit switch. Each steering axle 2 has a left turn limit switch and a right turn limit switch. The limit switch determines whether the telescopic displacement of the electric cylinder reaches the preset telescopic displacement, thereby determining the braking of the electric cylinder. When the telescopic displacement of the electric cylinder reaches the preset telescopic displacement, the electric cylinder controller will control the electric cylinder to stop the telescopic movement. Axle 1 is provided with an angle limit bolt. When the limit switch of the electric cylinder determines that the telescopic displacement of the electric cylinder has reached the preset maximum telescopic displacement and the electric cylinder no longer telescopes, the length of the axle limit bolt is adjusted to enable the axle to achieve the maximum angle mechanical limit, thereby protecting the electric cylinder to a certain extent.

[0025] The electric cylinder of the present invention replaces the hydraulic power cylinder and the neutral locking cylinder, and realizes electric power steering by replacing the original complex rod system connection through the electronic control program. One or more electric cylinders are arranged on each bridge housing. The controller of the electric cylinder can be integrated on the electric cylinder or arranged separately outside. The electric cylinder acts on the axle trapezoidal arm or the steering knuckle arm connected to the kingpin to drive the kingpin to rotate. The electric cylinder can move according to the angle value and direction input by the angle sensor, and can also actively control the telescopic displacement action according to the specific instructions of the electric steering control module. The electric power steering method involves heavy-duty engineering machinery vehicles, and the heavy-duty engineering machinery vehicles are cranes.

[0026] The steering angle sensor of the present invention can be located on the steering wheel or on the kingpin of the axle, and its function is to obtain the steering angle and direction signal. The electric steering control module can receive both the steering angle sensor signal and the vehicle speed signal and the steering sensing switch signal of the whole machine. The electric steering control module determines the telescopic and displacement stroke of the electric cylinder according to the value and direction of the steering angle sensor, and the electric cylinder controller controls the telescopic and displacement stroke of the electric cylinder according to the displacement stroke and telescopic direction instructions input by the electric steering control module. The number of electric cylinders and their controllers can be increased or decreased according to the demand for steering assistance, and the electric cylinders and their controllers correspond one to one. The electric cylinder is located on the axle trapezoidal arm, and the electric cylinder is operated by its controller to telescope and retract, driving the rotation of the axle trapezoidal arm, thereby realizing the left and right rotation of the wheel. The telescopic displacement stroke of the electric cylinder determines the angle of left and right rotation of the wheel.

[0027] The present invention is specifically controlled as follows:

[0028] When the electric steering control module and the electric cylinder controller are not powered, the electric cylinder is in a neutral braking state.

[0029] When both the electric steering control module and the electric cylinder controller are powered, the electric steering control module detects whether a steering switch command is received. If there is no steering switch command, the electric cylinder is in a neutral braking state. If there is, the vehicle speed signal of the entire machine is detected. If the vehicle speed is greater than the preset vehicle speed value, the electric steering control module sends a command signal to the electric cylinder controller, so that the electric cylinder corresponding to the electric cylinder controller is in a neutral braking state, thereby achieving a neutral locking state of one or more bridges; if the vehicle speed is less than the preset vehicle speed value, the electric steering control module continues to detect the steering angle sensor signal, processes the steering 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 action of the electric cylinder drives the wheels to achieve steering requirements.

[0030] The electric steering control module can issue control instructions to multiple bridges at the same time according to different steering control requirements, thereby realizing multiple steering modes for multiple bridges.

Claims

1. An electric power steering system, characterized in that: The invention comprises a rotation angle sensor, an electric steering control module, an electric cylinder controller, an electric cylinder, a wheel (1) and a steering axle (2) which are connected in sequence; the electric steering control module is connected to a steering switch, and the electric steering control module and the electric cylinder controller are both connected to a power source, which provides electric energy for the movement of the electric cylinder.

2. The electric power steering system according to claim 1, characterized in that: The rotation angle sensor obtains the rotation angle and rotation direction of the steering wheel or wheel (1); the electric steering control module receives the vehicle speed signal and the steering switch signal, and receives the steering wheel rotation angle and rotation direction signal from the rotation angle sensor; the electric cylinder controller receives the steering instruction from the electric steering control module to control the electric cylinder; one end of the electric cylinder is fixed to the axle housing of the steering axle (2), and the other end is fixed to the steering trapezoidal knuckle arm (5), and can also be fixed to the steering knuckle arm connected to the steering kingpin; the electric steering control module gives the electric cylinder controller corresponding instructions to drive the electric cylinder to move, thereby driving the wheel (1) to rotate to realize the steering function.

3. The electric power steering system according to claim 2, characterized in that: The electric steering control module, electric cylinder controller and electric cylinder form an electric cylinder assembly (3); the steering trapezoidal knuckle arm (5) is located on the side of the wheel (1); and the steering trapezoidal knuckle arms (5) on both sides are connected via a tie rod (4).

4. The electric power steering system according to claim 1, characterized in that: 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.

5. The electric power steering system according to claim 4, characterized in that: When the vehicle speed signal received by the electric steering control module is greater than a predetermined vehicle speed value, the electric steering control module controls the electric cylinders of a certain bridge or multiple bridges to be in a neutral braking state.

6. The electric power steering system according to claim 1, characterized in that: The electric cylinders are provided with neutral brakes. When the electric cylinders are not powered, all the electric cylinders are in a neutral braking state.

7. The electric power steering system according to claim 1, characterized in that: When the steering switch signal is off or there is no steering switch signal, all electric cylinders are in a neutral braking state.

8. The electric power steering system according to claim 1, characterized in that: The electric cylinder is provided with a limit switch. Each steering axle (2) is provided with a left-turn limit switch and a right-turn limit switch. The limit switch determines whether the telescopic displacement of the electric cylinder reaches a preset telescopic displacement, thereby determining the braking of the electric cylinder. When the telescopic displacement of the electric cylinder reaches the preset telescopic displacement, the electric cylinder controller controls the electric cylinder to stop the telescopic movement.

9. The electric power steering system according to claim 8, characterized in that: The axle (1) is provided with an angle limit bolt. When the limit switch of the electric cylinder determines that the telescopic displacement of the electric cylinder has reached a preset maximum telescopic displacement and the electric cylinder no longer telescopes, the length of the axle limit bolt is adjusted so that the axle achieves the maximum angle mechanical limit, thereby protecting the electric cylinder to a certain extent.

10. A crane using the electric power steering system according to any one of claims 1 to 9.

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