CN211519640U

CN211519640U - Hydraulic steering system, chassis and engineering vehicle

Info

Publication number: CN211519640U
Application number: CN201922450162.6U
Authority: CN
Inventors: 孙占瑞; 张勇; 张鑫; 陈成
Original assignee: Construction Machinery Branch of XCMG
Current assignee: Jiangsu Xugong Construction Machinery Research Institute Co ltd
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-09-18
Anticipated expiration: 2029-12-30

Abstract

The utility model discloses a hydraulic steering system, chassis and engineering vehicle relates to the engineering machine tool field. The hydraulic steering system comprises a pump, a steering oil cylinder, a reversing valve and a control assembly. The pump is configured to provide hydraulic oil. The direction change valve is provided between the pump and the steering cylinder, and is configured to switch the action of the steering cylinder. The control assembly is connected with the reversing valves and is configured to switch the valve positions of the reversing valves. Wherein, the quantity of steering cylinder and switching-over valve is a plurality of, and sets up correspondingly.

Description

Hydraulic steering system, chassis and engineering vehicle

Technical Field

The utility model relates to an engineering machine tool field, concretely relates to hydraulic steering system, chassis and engineering vehicle.

Background

The conventional passenger vehicles and commercial vehicles mostly run and transport on roads, and the conventional front wheel steering or front group wheel steering can meet the use requirements. However, for some dedicated wheeled construction machines, the work is often required to be performed under various complicated field conditions, and in order to meet the use requirements of the complicated field, higher requirements are provided for the steering system of the wheeled construction machine.

At present, in order to cope with a complicated road surface condition, a construction vehicle is generally provided with a device for realizing a function of a plurality of steering modes. Common forms of steering are: independent steering of front wheels, independent steering of rear wheels, full-wheel steering, crab steering, pivot steering and the like. Although the driver can select different steering modes to a certain extent according to needs, the maneuvering flexibility of the engineering vehicle is still deficient.

SUMMERY OF THE UTILITY MODEL

The utility model provides a hydraulic steering system and engineering vehicle for optimize hydraulic system's performance.

An embodiment of the utility model provides a hydraulic steering system, include:

a pump configured to provide hydraulic oil;

a steering cylinder;

a direction change valve provided between the pump and the steering cylinder and configured to switch an action of the steering cylinder; and

a control assembly connected with the direction valves and configured to switch the valve positions of the direction valves;

the steering oil cylinders and the reversing valves are multiple in number and are arranged correspondingly.

In some embodiments, each of the directional valves is independent of each other, and each of the steering cylinders is independent of each other.

In some embodiments, the number of the steering cylinders is four, and the number of the reversing valves is also four, and one steering cylinder corresponds to one reversing valve;

each steering oil cylinder is a telescopic oil cylinder, and the state of each steering oil cylinder meets one of the following conditions:

the first steering oil cylinder and the second steering oil cylinder are in the same telescopic state, and the third steering oil cylinder and the fourth steering oil cylinder are kept in the middle positions;

the first steering oil cylinder and the second steering oil cylinder keep the middle position, and the telescopic states of the third steering oil cylinder and the fourth steering oil cylinder are the same;

the telescopic states of the first steering oil cylinder and the second steering oil cylinder are the same, the telescopic states of the third steering oil cylinder and the fourth steering oil cylinder are the same, and the telescopic states of the first steering oil cylinder and the third steering oil cylinder 8 are opposite;

the first steering oil cylinder, the second steering oil cylinder, the third steering oil cylinder and the fourth steering oil cylinder are in the same telescopic state;

the telescopic states of the first steering oil cylinder and the second steering oil cylinder are opposite, the telescopic states of the third steering oil cylinder and the fourth steering oil cylinder are opposite, and the telescopic states of the first steering oil cylinder and the fourth steering oil cylinder are the same.

each steering oil cylinder is a steering oil cylinder, and the state of each steering oil cylinder meets one of the following conditions:

the first steering oil cylinder and the second steering oil cylinder have the same rotation state, and the third steering oil cylinder and the fourth steering oil cylinder keep a middle position;

the first steering oil cylinder and the second steering oil cylinder keep a middle position, and the rotation states of the third steering oil cylinder and the fourth steering oil cylinder are the same;

the rotation states of the first steering oil cylinder and the second steering oil cylinder are the same, the retraction rotation states of the third steering oil cylinder and the fourth steering oil cylinder are the same, and the rotation states of the first steering oil cylinder and the third steering oil cylinder are opposite;

the rotation states of the first steering oil cylinder, the second steering oil cylinder, the third steering oil cylinder and the fourth steering oil cylinder are the same;

the rotation states of the first steering oil cylinder and the second steering oil cylinder are opposite, the rotation states of the third steering oil cylinder and the fourth steering oil cylinder are opposite, and the rotation states of the first steering oil cylinder and the fourth steering oil cylinder are the same.

In some embodiments, the reversing valve comprises a four-position, four-way reversing valve.

In some embodiments, a hydraulic lock is arranged on an oil path between each reversing valve and the steering oil cylinder.

In some embodiments, an overflow valve is disposed on an oil path between each hydraulic lock and the steering cylinder.

In some embodiments, a check valve is arranged on an oil path between the overflow valve and the steering cylinder.

The utility model discloses other embodiments provide a chassis, including the wheel and the utility model discloses the hydraulic steering system that any technical scheme provided, every wheel connection is one steering cylinder.

The utility model discloses some embodiments provide an engineering vehicle again, include the utility model discloses the chassis that any technical scheme provided.

In some embodiments, the work vehicle comprises a fire engine.

According to the hydraulic steering system provided by the technical scheme, each steering oil cylinder corresponds to one actuating element, and the actuating element is a tire. The steering cylinders and the reversing valves are in one-to-one correspondence, namely the valve position of each reversing valve is not influenced by the valve positions of other reversing valves, and the extending and retracting states of each steering cylinder are not influenced by the extending and retracting states of other steering cylinders. The control assembly independently controls the valve position of each reversing valve, so that the extending and retracting states of each steering oil cylinder are independently controlled, and the action of the tire connected with the steering oil cylinder is also independent.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without undue limitation to the invention. In the drawings:

fig. 1 is a schematic diagram of a hydraulic steering system according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a chassis to which the hydraulic steering system according to the embodiment of the present invention is applied;

FIG. 3 is an enlarged view of part A of FIG. 2;

fig. 4 is a schematic diagram of a control principle of a hydraulic steering system according to an embodiment of the present invention;

fig. 5 is a schematic view of a front wheel steering of a hydraulic steering system according to an embodiment of the present invention;

fig. 6 is a schematic view of a rear wheel steering of a hydraulic steering system according to an embodiment of the present invention;

fig. 7 is a schematic view of an all-wheel steering of a hydraulic steering system according to an embodiment of the present invention;

fig. 8 is a crab-shaped steering schematic diagram of the hydraulic steering system provided by the embodiment of the present invention;

fig. 9 is a schematic pivot steering diagram of a hydraulic steering system according to an embodiment of the present invention.

Detailed Description

The technical solution provided by the present invention will be explained in more detail with reference to fig. 1 to 9.

Referring to fig. 1, an embodiment of the present invention provides a hydraulic steering system, which includes a pump 1, a steering cylinder 13, a reversing valve 2, and a control assembly 14. The pump 1 is configured to supply hydraulic oil. The selector valve 2 is provided between the pump 1 and the steering cylinder 13, and is configured to switch the operating state of the steering cylinder 13. The control assembly 14 is connected to the directional valves 2 and is configured to switch the valve position of each directional valve 2. Wherein, the quantity of the steering oil cylinder 13 and the reversing valve 2 is a plurality of, and the steering oil cylinder and the reversing valve are arranged correspondingly. Specifically, one steering cylinder 13 corresponds to one direction change valve 2.

Referring to fig. 1, in some embodiments, the directional valves 2 are independent of each other and the steering cylinders 13 are independent of each other. In fig. 1, four directional control valves are shown, one steering cylinder 13 for each directional control valve 2.

Referring to fig. 1 and 2, in some embodiments, the reversing valve 2 comprises a four-position, four-way reversing valve 2. Each reversing valve 2 comprises four working oil ports.

The four reversing valves 2 are all electro-hydraulic servo control valves and are all arranged on oil paths of the oil pump 1 and the steering oil cylinder 13, and each reversing valve 2 is provided with four working oil ports and four working positions. The oil ports of the reversing valves 2 are connected in a similar manner: the first working oil port and the second working oil port are respectively communicated with the oil port of the oil pump 1 and the oil tank, and the third working oil port and the fourth working oil port are respectively communicated with the A, B oil ports of the steering oil cylinder 13 controlled by the third working oil port and the fourth working oil port. When each reversing valve 2 is in the first working position (i.e. the uppermost valve position in fig. 1), the first working oil port, the third working oil port and the fourth working oil port are not communicated. The second working oil port is communicated with the third working oil port and the fourth working oil port. When each reversing valve 2 is in the second working position (i.e., the second valve position from the top in fig. 1), the first working oil port and the fourth working oil port are communicated, and the second working oil port and the third working oil port are communicated. When each reversing valve 2 is in the third working position (i.e., the third valve position from the top in fig. 1), the first working oil port, the second working oil port, the third working oil port, and the fourth working oil port are completely connected. When each reversing valve 2 is in the fourth working position (i.e. the lowest valve position in fig. 1), the first working oil port and the third working oil port are communicated, and the second working oil port and the fourth working oil port are communicated.

The steering cylinder 13 is specifically, for example, a telescopic cylinder or a rotary cylinder, and in the embodiments illustrated in fig. 1 and 2, the steering cylinder 13 is exemplified by a rotary cylinder.

The control of the control unit 14 to achieve the telescopic state of the steering cylinder 13 will now be described.

Referring to fig. 1, in some embodiments, there are four steering cylinders 13 and four direction valves 2, and one steering cylinder 13 corresponds to one direction valve 2. The four steering cylinders 13 are respectively: a first steering oil cylinder 6, a second steering oil cylinder 7, a third steering oil cylinder 8 and a fourth steering oil cylinder 9.

The first steering cylinder 6 corresponds to a front right tire of the engineering vehicle, the second steering cylinder 7 corresponds to a front left tire of the engineering vehicle, the third steering cylinder 8 corresponds to a rear right tire of the engineering vehicle, and the fourth steering cylinder 9 corresponds to a rear left tire of the engineering vehicle. The first steering cylinder 6 includes a first steering cylinder port 6A and a first steering cylinder another port 6B. The second steering cylinder 7 comprises a second steering cylinder oil port 7A and a second steering cylinder other oil port 7B. The third steering cylinder 8 comprises a third steering cylinder oil port 8A and a third steering cylinder other oil port 8B. The fourth steering cylinder 9 includes a fourth steering cylinder oil port 9A and a fourth steering cylinder another oil port 9B.

Referring to fig. 1, the four direction valves 2 are a first direction valve 2, a second direction valve 2, a third direction valve 2, and a fourth direction valve 2.

The first direction valve 221 includes a first working port 211, a second working port 212, a third working port 213, and a fourth working port 214.

The second direction valve 222 includes a first working fluid port 221, a second working fluid port 222, a third working fluid port 223, and a fourth working fluid port 224.

The third direction valve 223 includes a first working port 231, a second working port 232, a third working port 233, and a fourth working port 234.

The fourth direction valve 224 includes a first working port 241, a second working port 242, a third working port 243, and a fourth working port 244.

If each steering cylinder 13 is a telescopic cylinder, the telescopic state of each steering cylinder 13 satisfies one of the following conditions:

the first situation is as follows: the first steering cylinder 6 and the second steering cylinder 7 are in the same telescopic state, such as both extending or both retracting. The third steering oil cylinder 8 and the fourth steering oil cylinder 9 are kept at middle positions and do not extend or retract. The situation corresponds to the steering of the front wheels of the engineering vehicle.

Case two: the first steering oil cylinder 6 and the second steering oil cylinder 7 are kept in the neutral positions and do not extend or retract. The third steering cylinder 8 and the fourth steering cylinder 9 are in the same telescopic state, such as both extending or both retracting. This situation corresponds to the engineering vehicle rear wheel steering.

Case three: the first steering cylinder 6 and the second steering cylinder 7 are in the same telescopic state, such as both extending or both retracting. The third steering cylinder 8 and the fourth steering cylinder 9 are retracted in the same telescopic state, such as both extended or both retracted. In addition, the first steering oil cylinder 6 and the third steering oil cylinder 8 are opposite in expansion and contraction states, for example, if the first steering oil cylinder 6 extends out, the third steering oil cylinder 8 retracts; or vice versa. This situation corresponds to all-wheel steering of the engineering vehicle.

Case four: the first steering cylinder 6, the second steering cylinder 7, the third steering cylinder 8 and the fourth steering cylinder 9 are in the same telescopic state, such as being extended or retracted. The situation corresponds to crab steering of the engineering vehicle.

Case five: the telescopic states of the first steering oil cylinder 6 and the second steering oil cylinder 7 are opposite, the telescopic states of the third steering oil cylinder 8 and the fourth steering oil cylinder 9 are opposite, and the telescopic states of the first steering oil cylinder 6 and the fourth steering oil cylinder 9 are the same. This situation corresponds to the engineering vehicle turning in place.

If each of the steering cylinders 13 is a rotation cylinder, the rotation state of each of the steering cylinders 13 satisfies one of the following conditions:

the first situation is as follows: the first steering cylinder 6 and the second steering cylinder 7 are rotated in the same state, for example, both clockwise or both counterclockwise. The third steering cylinder 8 and the fourth steering cylinder 9 are kept at the middle positions and do not rotate. The situation corresponds to the steering of the front wheels of the engineering vehicle.

Case two: the first steering oil cylinder 6 and the second steering oil cylinder 7 are kept in the middle position and do not rotate. The third steering cylinder 8 and the fourth steering cylinder 9 are rotated in the same state, for example, both clockwise or both counterclockwise. This situation corresponds to the engineering vehicle rear wheel steering.

Case three: the first steering cylinder 6 and the second steering cylinder 7 are rotated in the same state, for example, both clockwise or both counterclockwise. The third steering cylinder 8 and the fourth steering cylinder 9 are rotated in the same state, for example, both clockwise or both counterclockwise. Moreover, the rotation states of the first steering cylinder 6 and the third steering cylinder 8 are opposite, for example, if the first steering cylinder 6 rotates clockwise, the third steering cylinder 8 rotates counterclockwise; or vice versa. This situation corresponds to all-wheel steering of the engineering vehicle.

Case four: the rotation states of the first steering cylinder 6, the second steering cylinder 7, the third steering cylinder 8 and the fourth steering cylinder 9 are the same, such as all clockwise rotation or all counterclockwise rotation. The situation corresponds to crab steering of the engineering vehicle.

Case five: the rotation states of the first steering cylinder 6 and the second steering cylinder 7 are opposite, the rotation states of the third steering cylinder 8 and the fourth steering cylinder 9 are opposite, and the rotation states of the first steering cylinder 6 and the fourth steering cylinder 9 are the same. This situation corresponds to the engineering vehicle turning in place.

Referring to fig. 1, in some embodiments, a hydraulic lock 3 is provided on an oil path between each direction change valve 2 and the steering cylinder 13.

The four hydraulic locks 3 are a first hydraulic lock 31, a second hydraulic lock 32, a third hydraulic lock 33, and a fourth hydraulic lock 34.

Referring to fig. 1, four hydraulic locks 3 are respectively disposed between each steering cylinder 13 and the corresponding directional control valve 2, and are respectively communicated with A, B oil ports of the steering cylinders 13 and third and fourth working oil ports of the corresponding directional control valves 2. Each hydraulic lock 3 is composed of two hydraulic control one-way valves 5, control oil ports of the hydraulic locks are communicated with a liquid inlet of the other hydraulic control one-way valve, and a passage between the oil port of the self-steering oil cylinder 13A, B and the corresponding reversing valve 2 is locked in a normal state.

Referring to fig. 1, the first port of the first hydraulic lock 31 communicates with the third working port 213, and the second port of the first hydraulic lock 31 communicates with the fourth working port 214. The third port of the first hydraulic lock 31 is communicated with the first steering cylinder port 6A, and the fourth port of the first hydraulic lock 31 is communicated with the other port 6B of the first steering cylinder.

The first port of the second hydraulic lock 32 communicates with the third working port 223, and the second port of the second hydraulic lock 32 communicates with the fourth working port 224. The third oil port of the second hydraulic lock 32 is communicated with the second steering cylinder oil port 7A, and the fourth oil port of the second hydraulic lock 32 is communicated with the other oil port 7B of the second steering cylinder.

The first port of the third hydraulic lock 33 is communicated with the third working port 233, and the second port of the third hydraulic lock 33 is communicated with the fourth working port 234. The third oil port of the first hydraulic lock 31 is communicated with the third steering cylinder oil port 8A, and the fourth oil port of the first hydraulic lock 31 is communicated with the other oil port 8B of the third steering cylinder.

The first port of the fourth hydraulic lock 34 is communicated with the third working port 243, and the second port of the fourth hydraulic lock 34 is communicated with the fourth working port 244. A third oil port of the fourth hydraulic lock 34 is communicated with a fourth steering cylinder oil port 9A, and a fourth oil port of the fourth hydraulic lock 34 is communicated with the other oil port 9B of the fourth steering cylinder.

In some embodiments, a relief valve 4 is provided on the oil path between each hydraulic lock 3 and the steering cylinder 13.

Referring to fig. 1, the relief valves 4 are respectively disposed on the pipelines between the two ports of the hydraulic lock 3 and the A, B port of the corresponding steering cylinder 13 and the oil tank.

Specifically, the relief valve 4 includes four relief valves, i.e., a first relief valve 41, a second relief valve 42, a third relief valve 43, and a fourth relief valve 44.

Referring to fig. 1, a first relief valve 41 is installed on an oil path between the first hydraulic lock 31 and the first steering cylinder 6. A first port of the first overflow valve 41 is communicated with the first steering cylinder port 6A, and a second port of the first overflow valve 41 is communicated with the other port 6B of the first steering cylinder.

Referring to fig. 1, the second relief valve 42 is mounted on the oil passage between the second hydraulic lock 32 and the second steering cylinder 7. A first oil port of the second overflow valve 42 is communicated with the second steering cylinder oil port 7A, and a second oil port of the second overflow valve 42 is communicated with the other oil port 7B of the second steering cylinder.

Referring to fig. 1, a third relief valve 43 is mounted on the oil passage between the third hydraulic lock 33 and the third steering cylinder 8. A first oil port of the third overflow valve 43 is communicated with the third steering cylinder oil port 8A, and a second oil port of the third overflow valve 43 is communicated with the other oil port 8B of the third steering cylinder.

Referring to fig. 1, the fourth spill valve 44 is installed on an oil path between the fourth hydraulic lock 34 and the fourth steering cylinder 9. A first port of the fourth overflow valve 44 is communicated with the fourth steering cylinder port 9A, and a second port of the fourth overflow valve 44 is communicated with the other port 9B of the fourth steering cylinder.

Referring to fig. 1, in some embodiments, a check valve 5 is provided on an oil path between the relief valve 4 and the steering cylinder 13.

The check valves 5 are respectively arranged on the pipelines between the two oil ports of the hydraulic lock 3 and the oil port of the corresponding steering oil cylinder 13A, B and the oil tank, and the liquid inlet of each check valve 5 is communicated with the oil tank.

The specific connection mode is as follows:

referring to fig. 1, two first check valves 51 are provided on an oil path between the first relief valve 41 and the first steering cylinder 6. The oil inlets of the two first check valves 51 are both communicated with the third oil port of the first overflow valve 41. The third port of the first relief valve 41 communicates with the oil return port T. An oil outlet of one first check valve 51 is connected with a first steering cylinder oil port 6A, and an oil outlet of the other first check valve 51 is connected with the other first steering cylinder oil port 6B.

Referring to fig. 1, two second check valves 52 are provided on the oil passage between the second relief valve 42 and the second steering cylinder 7. The oil inlets of the two second check valves 52 are both communicated with the third oil inlet of the second overflow valve 42. The third port of the second relief valve 42 communicates with the oil return port T. An oil outlet of one first check valve 51 is connected with the second steering cylinder oil port 7A, and an oil outlet of the other first check valve 51 is connected with the other second steering cylinder oil port 7B.

Referring to fig. 1, two third check valves 53 are provided on the oil passage between the third relief valve 43 and the third steering cylinder 8. The oil inlets of the two third check valves 53 are communicated with the third oil port of the third overflow valve 43. The third port of the third relief valve 43 communicates with the oil return port T. An oil outlet of one of the third check valves 53 is connected with a third steering cylinder oil port 8A, and an oil outlet of the other third check valve 53 is connected with another third steering cylinder oil port 8B.

Two fourth check valves 54 are provided on an oil path between the fourth spill valve 44 and the fourth steering cylinder 9. The oil inlets of both fourth check valves 54 are in communication with the third port of the fourth spill valve 44. The third port of the fourth spill valve 44 communicates with the oil return port T. An oil outlet of one of the fourth check valves 54 is connected with a fourth steering cylinder oil port 9A, and an oil outlet of the other fourth check valve 54 is connected with another oil port 9B of the fourth steering cylinder.

The multi-mode steering hydraulic control system provided by the technical scheme realizes steering modes such as independent steering of the front wheels, independent steering of the rear wheels, all-wheel steering, crab steering, pivot steering and the like, a driver can select different steering modes according to different operation and site conditions, and the maneuvering flexibility of the engineering vehicle is greatly improved; the cost of the whole machine is effectively controlled, and reliable guarantee is provided for the safety and stability of relevant operation.

The embodiment of the utility model provides a still provide a chassis, including the wheel and the utility model discloses hydraulic steering system that any technical scheme provided, steering cylinder 13 of every wheel connection.

The steering oil cylinder 13 is a rotary swing oil cylinder and is arranged between the frame and the wheel driving device, the side flange is fixedly connected with the frame, and the bottom flange is fixedly connected with the wheel driving device. The steering cylinder 13 is provided with A, B two oil ports. When the oil A enters and exits from the oil B, the oil cylinder rotates clockwise (vertical to the oil cylinder and looking downwards), and the corresponding wheels are driven to rotate clockwise. When the oil B enters and exits from the oil A, the oil cylinder rotates anticlockwise (vertical to the oil cylinder and looks downwards), and the corresponding wheels are driven to rotate anticlockwise.

Referring to fig. 2, the chassis includes a first steering cylinder 6, a second steering cylinder 7, a third steering cylinder 8, a fourth steering cylinder 9, a frame 10, a wheel driving device 11, and four wheels 12.

Fig. 3 illustrates the first steering cylinder 6, the frame 10, the wheel driving device 11, the wheel 12, the first steering cylinder port 6A and the first steering cylinder other port 6B, a side flange 61 of the first steering cylinder 6, and a bottom flange 62 of the first steering cylinder 6.

The multi-mode steering control process comprises the following steps: the driver selects a steering mode at first, operates the steering wheel, the steering angle encoder transmits a steering wheel steering angle signal to the controller, data processing and conversion are carried out by applying Ackerman steering angle law, the controller outputs a steering angle signal to each electromagnetic directional valve 2 to promote the valve core to move, so that the working position of the valve is changed, the oil entering and exiting direction of the steering oil cylinder 13 is changed, and therefore the rotation direction of the steering oil cylinder 13 is determined by the rotation of the steering wheel.

All the reversing valves 2 are servo reversing valves, reversing work is carried out under the condition of power supply, when a circuit fails in the working process, the reversing valves 2 are located at the first working position, the valve cores are located at the upper positions under the action of the springs, the steering oil cylinders 13 are not communicated with oil, wheels are not deflected, and driving safety is guaranteed. When the reversing valve 2 is powered on but no corner signal is input, the reversing valve 2 is in the third working position, oil is conducted, and the reversing valve is in a ready working state.

In the actual running process, if the wheels encounter hard objects such as a slope sill or a stone, a larger instantaneous pressure is generated in the inner cavity of the corresponding steering cylinder 13. In order to avoid the influence of pressure on the normal running of the system, the hydraulic locks 3 are respectively arranged between each steering oil cylinder 13 and the corresponding reversing valve 2, the passage between the steering oil cylinder 13 and the corresponding directional control valve is locked in a normal state, and when the instantaneous pressure is formed in the inner cavity of any steering oil cylinder 13, the instantaneous pressure cannot reversely flow to the reversing valve 2, so that the normal running of the system is influenced. And when the pressure reaches the specified pressure, the overflow valve 4 works, the valve core is opened, the oil port of the steering oil cylinder 13 is communicated with the oil tank, the pressure is relieved, and the hydraulic element is prevented from being damaged due to overlarge pressure.

No oil liquid enters the steering oil cylinder 13 from the reversing valve 2 in the stopping stage of the steering process, negative pressure is easily formed in the cavity of the steering oil cylinder 13 due to the steering inertia effect, at the moment, the one-way valve 5 works, the oil liquid flows into the negative pressure cavity of the corresponding oil cylinder from the oil tank to supplement oil for the oil cylinder, the safe work of the oil cylinder is ensured, and the negative pressure is prevented from influencing the service life of a system pipeline and elements.

The working principle of the steering device in five steering modes is as follows: (to turn right to the example)

(1) Front wheel steering mode: the first reversing valve 221 obtains a first turning angle signal S1, the second reversing valve 222 obtains a second turning angle signal S2, the valve core is located at a fourth working position, the first working oil port is communicated with the third working oil port, the second working oil port is communicated with the fourth working oil port, oil flows into the first steering oil cylinder oil port 6A and the second steering oil cylinder oil port 7A, and the first steering oil cylinder 6 and the second steering oil cylinder 7 rotate clockwise to drive the right front wheel and the left front wheel to rotate rightwards. The third direction changing valve 223 and the fourth direction changing valve 224 have no electromagnetic signal input and are still in the preparation state, and the wheels do not deflect.

(2) Rear wheel steering mode: the third reversing valve 223 obtains a third corner signal S3, the fourth reversing valve 224 obtains a fourth corner signal S4, the valve core is located at the second working position, the first working oil port is communicated with the fourth working oil port, the second working oil port is communicated with the third working oil port, the oil flows into the other oil port 8B of the third steering oil cylinder and the other oil port 9B of the fourth steering oil cylinder, and the third steering oil cylinder 8 and the fourth steering oil cylinder 9 rotate anticlockwise to drive the right rear wheel and the left rear wheel to rotate leftwards. The first direction valve 221 and the second direction valve 222 have no electromagnetic signal input and are still in the preparation state, and the wheels are not deflected.

(3) Four-wheel steering mode: the first reversing valve 221 obtains a first turning angle signal S1, the second reversing valve 222 obtains a second turning angle signal S2, the valve core is located at a fourth working position, the first working oil port is communicated with the third working oil port, the second working oil port is communicated with the fourth working oil port, and oil flows into the first steering oil cylinder oil port 6A and the second steering oil cylinder oil port 7A. The first steering oil cylinder 6 and the second steering oil cylinder 7 rotate clockwise to drive the right and left front wheels to rotate rightwards.

The third reversing valve 223 obtains a third corner signal S3, the fourth reversing valve 224 obtains a fourth corner signal S4, the valve core is located at the second working position, the first working oil port is communicated with the fourth working oil port, the second working oil port is communicated with the third working oil port, the oil flows into the other oil port 8B of the third steering oil cylinder and the other oil port 9B of the fourth steering oil cylinder, and the third steering oil cylinder 8 and the fourth steering oil cylinder 9 rotate anticlockwise to drive the right and left rear wheels to rotate leftwards.

(4) Crab steering mode: the first reversing valve 221 obtains a first corner signal S1, the second reversing valve 222 obtains a second corner signal S2, the third reversing valve 223 obtains a third corner signal S3, the fourth reversing valve 224 obtains a fourth corner signal S4, the valve core is located at a fourth working position, the first working oil port is communicated with the third working oil port, and the second working oil port is communicated with the fourth working oil port.

The oil liquid flows into the first steering cylinder oil port 6A, the second steering cylinder oil port 7A, the third steering cylinder oil port 8A and the fourth steering cylinder oil port 9A. The first steering oil cylinder 6, the second steering oil cylinder 7, the third steering oil cylinder 8 and the fourth steering oil cylinder 9 all rotate clockwise to drive the wheels of the steering oil cylinders to rotate rightwards.

(5) In the pivot steering mode: the first reversing valve 221 obtains a first corner signal S1, the fourth reversing valve 224 obtains a fourth corner signal S4, the valve core is located at the second working position, the first working oil port is communicated with the fourth working oil port, and the second working oil port is communicated with the third working oil port.

The oil liquid flows into the other oil port 6B of the first steering oil cylinder and the oil port 9B of the fourth steering oil cylinder, and the first steering oil cylinder and the fourth steering oil cylinder 9 rotate anticlockwise to drive the right front wheel and the left rear wheel to rotate leftwards. The second reversing valve 222 obtains a second corner signal S2, the third reversing valve 223 obtains a third corner signal S3, the valve core is located at a fourth working position, the first working oil port is communicated with the third working oil port, and the second working oil port is communicated with the fourth working oil port.

The oil liquid flows into the second steering oil cylinder oil port 7A and the third steering oil cylinder oil port 8A, and the second steering oil cylinder 7 and the third steering oil cylinder 8 rotate clockwise to drive the left front wheel and the right rear wheel to rotate rightwards. Pivot steering refers to the circular motion of a vehicle around its own geometric center.

The two front wheels deflect towards the inner side of the vehicle and are in an inner splayed shape, and the two rear wheels deflect towards the outer side of the vehicle and are in an outer splayed shape. The direction of movement of each wheel is shown in the direction of the arrow in the following figure (or vice versa). In other steering modes (front wheels, rear wheels, four wheels, crab walking), the two front wheels have the same deflection direction, and the two rear wheels have the same deflection direction. The pivot steering greatly reduces the turning radius of the vehicle and improves the maneuvering flexibility of the vehicle.

The multi-mode steering hydraulic control system provided by the technical scheme realizes five steering modes of independent steering of front wheels, independent steering of rear wheels, all-wheel steering, crab steering and pivot steering of the vehicle through the combined application of the steering servo valve, the hydraulic lock 3 and other hydraulic elements. The driver can select different steering modes according to different operation and site conditions, and the maneuvering flexibility of the engineering vehicle is greatly improved. The system has clear principle and convenient maintenance, can effectively control the cost of the whole machine, and provides reliable guarantee for the safety and stability of relevant operation.

It should be noted that the vehicle according to the present embodiment can realize all-wheel independent steering under the action of the steering cylinder 13, and therefore, the number of the directional control valves 2 is the same as the number of the vehicle wheels, and in a specific case, the present embodiment is described by taking a four-wheel vehicle as an example, and the present embodiment is also applicable to wheeled vehicles with other numbers of wheels.

The embodiment of the utility model provides an engineering vehicle is provided again, include the utility model discloses the chassis that any technical scheme provided.

In some embodiments, the work vehicle comprises a fire engine.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the scope of the present invention.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: it is to be understood that modifications may be made to the above-described arrangements in the embodiments or equivalents may be substituted for some of the features of the embodiments, but such modifications or substitutions do not depart from the spirit and scope of the present invention.

Claims

1. A hydraulic steering system, comprising:

a pump (1) configured to provide hydraulic oil;

a steering cylinder (13);

a direction change valve (2) provided between the pump (1) and the steering cylinder (13) and configured to switch the action of the steering cylinder (13); and

a control assembly (14) connected to the directional valves (2) and configured to switch the valve position of each directional valve (2);

the steering oil cylinders (13) and the reversing valves (2) are multiple in number and are arranged correspondingly.

2. A hydraulic steering system according to claim 1, characterized in that the respective reversing valves (2) are independent of each other and the steering cylinders (13) are independent of each other.

3. The hydraulic steering system according to claim 1, characterized in that said steering cylinders (13) are four, said direction-changing valves (2) are also four, one steering cylinder (13) for each direction-changing valve (2);

wherein each steering cylinder (13) is a telescopic cylinder, and the state of each steering cylinder (13) satisfies one of the following conditions:

the first steering oil cylinder (6) and the second steering oil cylinder (7) are in the same telescopic state, and the third steering oil cylinder (8) and the fourth steering oil cylinder (9) are kept in the middle positions;

the first steering oil cylinder (6) and the second steering oil cylinder (7) keep neutral positions, and the telescopic states of the third steering oil cylinder (8) and the fourth steering oil cylinder (9) are the same;

the telescopic states of the first steering oil cylinder (6) and the second steering oil cylinder (7) are the same, the retracted telescopic states of the third steering oil cylinder (8) and the fourth steering oil cylinder (9) are the same, and the telescopic states of the first steering oil cylinder (6) and the third steering oil cylinder (8) are opposite;

the first steering oil cylinder (6), the second steering oil cylinder (7), the third steering oil cylinder (8) and the fourth steering oil cylinder (9) are in the same telescopic state;

the telescopic states of the first steering oil cylinder (6) and the second steering oil cylinder (7) are opposite, the telescopic states of the third steering oil cylinder (8) and the fourth steering oil cylinder (9) are opposite, and the telescopic states of the first steering oil cylinder (6) and the fourth steering oil cylinder (9) are the same.

4. The hydraulic steering system according to claim 1, characterized in that said steering cylinders (13) are four, said direction-changing valves (2) are also four, one steering cylinder (13) for each direction-changing valve (2);

wherein each steering cylinder (13) is a rotary cylinder, and the state of each steering cylinder (13) satisfies one of the following conditions:

the first steering oil cylinder (6) and the second steering oil cylinder (7) have the same rotation state, and the third steering oil cylinder (8) and the fourth steering oil cylinder (9) keep neutral positions;

the first steering oil cylinder (6) and the second steering oil cylinder (7) keep neutral positions, and the rotation states of the third steering oil cylinder (8) and the fourth steering oil cylinder (9) are the same;

the rotation states of the first steering oil cylinder (6) and the second steering oil cylinder (7) are the same, the retraction rotation states of the third steering oil cylinder (8) and the fourth steering oil cylinder (9) are the same, and the rotation states of the first steering oil cylinder (6) and the third steering oil cylinder (8) are opposite;

the rotation states of the first steering oil cylinder (6), the second steering oil cylinder (7), the third steering oil cylinder (8) and the fourth steering oil cylinder (9) are the same;

the rotating states of the first steering oil cylinder (6) and the second steering oil cylinder (7) are opposite, the rotating states of the third steering oil cylinder (8) and the fourth steering oil cylinder (9) are opposite, and the rotating states of the first steering oil cylinder (6) and the fourth steering oil cylinder (9) are the same.

5. The hydraulic steering system according to claim 1, characterized in that the reversing valve (2) comprises a four-position, four-way reversing valve.

6. The hydraulic steering system according to claim 1, characterized in that a hydraulic lock (3) is provided on the oil path between each directional control valve (2) and the steering cylinder (13).

7. The hydraulic steering system according to claim 6, characterized in that an overflow valve (4) is provided on the oil path between each hydraulic lock (3) and the steering cylinder (13).

8. The hydraulic steering system according to claim 7, characterized in that a check valve (5) is provided on the oil path between the spill valve (4) and the steering cylinder (13).

9. A chassis, characterized by comprising wheels and a hydraulic steering system according to any one of claims 1 to 8, each of said wheels being connected to one of said steering cylinders (13).

10. A work vehicle, characterized in that it comprises a chassis according to claim 9.

11. The work vehicle of claim 10, wherein the work vehicle comprises a fire engine.