A fully hydraulically controlled two-way driving system and its oil circuit switching method

Abstract

The present invention discloses a fully hydraulically controlled two-way driving system and an oil circuit switching method thereof. The system includes a front axle steering oil cylinder and a rear axle steering oil cylinder for performing steering actions, a front cab hydraulic steering gear and a rear cab hydraulic steering gear for controlling steering, a hydraulic pump for providing hydraulic oil, a filter for filtering the hydraulic oil provided by the hydraulic pump, a priority valve for controlling the flow of hydraulic oil, and a reversing valve group for oil circuit switching. The front and rear cabs are switched by setting a three-way ball valve group, and the system function is selected by setting three gears of a manual reversing valve group, thereby switching the oil circuit of the corresponding function, realizing vehicle steering, centering and turning operations, without electrical control throughout the process, avoiding the failure of the electromagnet burning out due to long-term power supply to the electromagnet, reducing the failure rate of the driving system, not easy to get stuck, working more reliably, improving the safety of the system, making the operation simpler, and effectively improving the work efficiency.

Description

Technical Field

[0001] The present invention relates to the field of engineering equipment, and in particular to a fully hydraulically controlled two-way driving system and an oil circuit switching method thereof. Background Art

[0002] In recent years, two-way vehicles have been used more and more widely. Compared with traditional one-way vehicles, two-way vehicles are more convenient in turning and driving in the opposite directions, especially in some specific narrow spaces, such as two-way subways and high-speed railways, and two-way excavators in tunnel projects.

[0003] The most obvious difference between a two-way vehicle and a one-way vehicle is that it has two cabs and two driving systems, namely the front cab and the rear cab. The operating principle is that when the front cab is driving, the steering gear of the rear cab is first operated to control the centering of the rear axle steering cylinder to realize the centering of the rear axle tire; then the steering gear of the front cab is operated to control the front axle steering cylinder to realize the front axle steering of the vehicle. Similarly, when driving the rear axle, the steering gear of the front cab is first operated to control the centering of the front axle steering cylinder to realize the centering of the front axle tire; then the steering gear of the rear cab is operated to control the front axle steering cylinder to realize the front axle steering of the vehicle. Although two-way vehicles have significant advantages over single-phase vehicles, the existing steering hydraulic control system usually uses electricity for oil circuit control. During long-term driving, the electromagnet is energized for a long time, which is easy to cause the electromagnet to burn out, resulting in steering failure, and the application of hydraulic valves is prone to jamming, and the control system has a high fixed failure rate. In addition, when turning, it is necessary to first enter the rear cab for centering and then enter the front cab for steering. The alternating operation of the two cabs also increases the workload of the operators. Summary of the invention

[0004] In view of this, the present invention provides a fully hydraulically controlled two-way driving system and an oil circuit switching method thereof, aiming to solve the technical problem of reducing the failure rate of the electro-hydraulic controlled two-way driving system and improving the operational convenience.

[0005] In order to solve the above technical problems, the technical solution of the present invention is to provide a fully hydraulically controlled two-way driving system, including a front axle steering cylinder and a rear axle steering cylinder for performing steering actions, a front cab hydraulic steering gear and a rear cab hydraulic steering gear for controlling steering, a hydraulic pump for providing hydraulic oil, a filter for filtering the hydraulic oil provided by the hydraulic pump, a priority valve for controlling the flow of hydraulic oil, and a reversing valve group for oil circuit switching.

[0006] In some embodiments, the reversing valve group for oil circuit switching includes a first hydraulically controlled reversing valve, a second hydraulically controlled reversing valve, a third hydraulically controlled reversing valve, a fourth hydraulically controlled reversing valve, and a fifth hydraulically controlled reversing valve; the first hydraulically controlled reversing valve and the second hydraulically controlled reversing valve are connected in series with the front axle steering cylinder; the third hydraulically controlled reversing valve and the fourth hydraulically controlled reversing valve are connected in series with the rear axle steering cylinder; the fifth hydraulically controlled reversing valve is connected in series with the front axle steering cylinder and the rear axle steering cylinder, respectively.

[0007] In some embodiments, the first hydraulically controlled reversing valve, the second hydraulically controlled reversing valve, the third hydraulically controlled reversing valve, the fourth hydraulically controlled reversing valve, and the fifth hydraulically controlled reversing valve all have a locking function.

[0008] In some embodiments, the reversing valve group for oil circuit switching further includes two manual reversing valves, and the two manual reversing valves are respectively arranged in the front cab and the rear cab.

[0009] In some embodiments, the two manual reversing valves are connected in parallel.

[0010] In some embodiments, the two manual reversing valves each have three gears, and the two manual reversing valves are respectively connected to a control handle, and the control handle is used to control the manual reversing valve to switch gears.

[0011] In some embodiments, the reversing valve group for oil circuit switching also includes a three-way ball valve group, which includes a first three-way ball valve and a second three-way ball valve. The first three-way ball valve is used for switching the front cab state; the second three-way ball valve is used for switching the rear cab state.

[0012] In some embodiments, a relief valve for protecting the safety of the oil circuit is further included, and the relief valve is arranged adjacent to the hydraulic pump.

[0013] In some embodiments, it also includes a shuttle valve group for oil circuit selection, the shuttle valve group includes a first shuttle valve, a second shuttle valve and a third shuttle valve, the first shuttle valve is arranged in the front cab hydraulic steering gear and the rear cab hydraulic steering gear; the second shuttle valve is arranged in the oil circuit adjacent to the rear axle steering cylinder; the third shuttle valve is arranged in the oil circuit adjacent to the front axle steering cylinder.

[0014] In addition, the present invention also provides an oil circuit switching method for full hydraulically controlled bidirectional driving, which is applied to the above-mentioned full hydraulically controlled bidirectional driving system, comprising:

[0015] A cab is selected, and according to the selected cab, the oil circuit is switched to a corresponding cab mode by controlling a three-way ball valve group, wherein the cab mode includes a front cab mode and a rear cab mode;

[0016] According to the selected cab mode, select the manual reversing valve gear to switch the oil circuit of the driving mode. Specifically,

[0017] If the manual reversing valve is in the first gear, the steering mode oil circuit is switched;

[0018] If the manual reversing valve is in the second gear, the centering mode oil circuit is switched;

[0019] If the manual reversing valve is in the third gear, the circle mode oil circuit is switched.

[0020] The present invention provides a fully hydraulically controlled two-way driving system and an oil circuit switching method thereof. The system includes a front axle steering cylinder and a rear axle steering cylinder for performing steering actions, a front cab hydraulic steering gear and a rear cab hydraulic steering gear for controlling steering, a hydraulic pump for providing hydraulic oil, a filter for filtering the hydraulic oil provided by the hydraulic pump, a priority valve for controlling the flow of hydraulic oil, and a reversing valve group for oil circuit switching. The front and rear cabs are switched by setting a three-way ball valve group, and the system function is selected by setting three gears of the manual reversing valve group, so as to switch the oil circuit of the corresponding function. The fully hydraulically controlled driving system ensures that there is no electrical control throughout the process, avoids the failure of the electromagnet burning out due to long-term power supply to the electromagnet, and reduces the failure rate of the driving system. At the same time, the fully hydraulically controlled system is not easy to get stuck, the operation is more reliable, and the safety of the system is improved. The free switching operation of the double cabs is simpler. The equipment steering switch can be operated in any cab, and the work efficiency of the operator can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 It is a system schematic diagram of a fully hydraulically controlled two-way driving system provided in one embodiment of the present application.

[0023] Description of reference numerals:

[0024] 1-front axle steering cylinder, 2-rear axle steering cylinder, 3-front cab hydraulic steering gear, 4-rear cab hydraulic steering gear, 5-priority valve, 6-filter, 7-overflow valve, 8-hydraulic pump, 9-first shuttle valve, 10-second shuttle valve, 11-third shuttle valve, 12-first hydraulically controlled reversing valve, 13-second hydraulically controlled reversing valve, 14-third hydraulically controlled reversing valve, 15-fourth hydraulically controlled reversing valve, 16-fifth hydraulically controlled reversing valve, 17-first manual reversing valve, 18-second manual reversing valve, 19-first three-way ball valve, 20-second three-way ball valve. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0026] In the traditional two-way driving hydraulic control scheme, the electro-hydraulic control mode is usually adopted. When driving the front axle, the rear cab steering gear is first operated to control the centering of the rear axle steering cylinder to realize the centering of the rear axle tire; then the front cab steering gear is operated to control the front axle steering cylinder to realize the front axle steering of the vehicle. Similarly, when driving the rear axle, the front cab steering gear is first operated to control the centering of the front axle steering cylinder to realize the centering of the front axle tire; then the rear cab steering gear is operated to control the front axle steering cylinder to realize the front axle steering of the vehicle. Among them, the output shaft of the front cab hydraulic steering gear is connected to the front cab steering gear key, and the output shaft of the rear cab hydraulic steering gear is connected to the rear cab steering gear key.

[0027] The traditional two-way driving control scheme can only realize the two-way driving function, and the functional structure is very simple. In addition, because the electro-hydraulic control mode is adopted, the electromagnet is in a long-term energized state during long-term vehicle driving, which can easily cause the electromagnet to burn out, resulting in steering failure, and the hydraulic valve is prone to jamming, making the equipment failure rate extremely high. In addition, when driving a two-way driving vehicle, whether it is front-axle driving or rear-axle driving, it is necessary to operate the steering machines of the front and rear cabs to align them, so as to realize the front-axle steering or rear-axle steering of the vehicle, which is extremely cumbersome.

[0028] In view of this, the present invention proposes a fully hydraulically controlled two-way driving system, such as Figure 1 As shown, it includes a front axle steering cylinder 1, a rear axle steering cylinder 2, a front cab hydraulic steering gear 3, a rear cab hydraulic steering gear 4, a priority valve 5, a filter 6, a relief valve 7, a hydraulic pump 8, a shuttle valve group, a hydraulically controlled reversing valve group, a manual reversing valve group and a three-way ball valve group.

[0029] The front axle steering cylinder and the rear axle steering cylinder are both used to perform steering actions; the front cab hydraulic steering gear and the rear cab hydraulic steering gear are both used to control the left and right steering of the vehicle; the hydraulic pump is used to provide hydraulic oil for the oil circuit; the filter is used to filter the hydraulic oil provided by the hydraulic pump; the priority valve is used to control the flow of hydraulic oil; the shuttle valve group is used to select the oil circuit, including a first shuttle valve 9 arranged at the front cab hydraulic steering gear and the rear cab hydraulic steering gear, a second shuttle valve 10 arranged near the rear axle steering cylinder, and a third shuttle valve 11 arranged near the front axle steering cylinder; the hydraulically controlled reversing valve group includes a first hydraulically controlled reversing valve 12, a second hydraulically controlled reversing valve 13, a third hydraulically controlled reversing valve 14, a fourth hydraulically controlled reversing valve 15, and a fifth hydraulically controlled reversing valve 16 for oil circuit switching. The five hydraulically controlled reversing valves of the hydraulically controlled reversing valve group all have a locking function. The first hydraulically controlled reversing valve and the second hydraulically controlled reversing valve are connected in series with the front axle steering cylinder, the third hydraulically controlled reversing valve and the fourth hydraulically controlled reversing valve are connected in series with the rear axle steering cylinder, and the fifth hydraulically controlled reversing valve is connected in series with the front axle steering cylinder and the rear axle steering cylinder respectively; the manual reversing valve group includes a first manual reversing valve 17 and a second manual reversing valve 18 connected in parallel, which are respectively arranged in the front cab and the rear cab, and each manual reversing valve has three gears for switching the vehicle steering, centering and turning functions; the three-way ball valve group includes a first three-way ball valve 19 and a second three-way ball valve 20. The first three-way ball valve is used for switching the front cab state, and the second three-way ball valve is used for switching the rear cab state.

[0030] In this embodiment, by selecting a hydraulically controlled reversing valve as the valve, the oil circuit control of the full hydraulic control system is achieved, the traditional electro-hydraulic control system is eliminated, and the long-term power supply to the electromagnet is avoided, which causes the electromagnet to burn out and leads to steering failure. Not only the failure rate is reduced, but also the safety is greatly guaranteed. In addition, by adding a three-way ball valve group to realize the switching of the cab status, the same cab can realize the system operation of the front cab and the system operation of the rear cab, and the convenience and practicality are greatly improved. The manual reversing valve group sets three gears to make the switching of the vehicle function operation simpler and more convenient, and the operation is smoother.

[0031] As a preferred embodiment, the present application also proposes a fully hydraulically controlled two-way driving oil circuit switching method, which is applied to a fully hydraulically controlled two-way driving system. By selecting a cab, according to the selected cab, the oil circuit is switched to the corresponding cab mode by controlling the three-way ball valve group, wherein the cab mode includes a front cab mode and a rear cab mode, and then according to the selected cab mode, the manual reversing valve gear is selected to switch the oil circuit of the driving mode, specifically:

[0032] If the manual reversing valve is in the first gear, the steering mode oil circuit is switched;

[0033] If the manual reversing valve is in the second gear, the centering mode oil circuit is switched;

[0034] If the manual reversing valve is in the third gear, the circle mode oil circuit is switched.

[0035] The principle of switching the steering mode oil circuit is to first switch to the front cab state or the rear cab state by switching the first three-way ball valve or the second three-way ball valve. After selecting the cab state, select the corresponding manual reversing valve (that is, when the front cab state is selected, the first manual reversing valve is selected, and when the rear cab state is selected, the second manual reversing valve is selected) to switch to the first gear. When the front cab state is selected at this time, operate the first manual reversing valve to switch to the first gear, open the first hydraulic control reversing valve and the second hydraulic control reversing valve, and close the third hydraulic control reversing valve, the fourth hydraulic control reversing valve, and the fifth hydraulic control reversing valve. When the front cab hydraulic steering gear is operated to rotate clockwise, the feedback oil circuit LS of the front cab hydraulic steering gear enters the priority valve through the first shuttle valve, causing the main valve core of the priority valve to change direction. At this time, the hydraulic oil enters the P port of the front cab hydraulic steering gear from the hydraulic pump outlet port through the priority valve, and then enters the lower chamber of the front axle steering cylinder from the R port of the front cab hydraulic steering gear through the first hydraulic-controlled reversing valve. The piston of the front axle steering cylinder moves up, and at the same time, the hydraulic oil enters the L port of the hydraulic steering gear from the upper chamber of the front axle steering cylinder through the second hydraulic-controlled reversing valve, thereby realizing the right steering operation of the front axle.

[0036] Similarly, when the front cab hydraulic steering gear is operated to rotate counterclockwise, the front cab hydraulic steering gear feedback oil circuit LS enters the priority valve through the first shuttle valve, causing the priority valve main valve core to reverse. At this time, the hydraulic oil enters the P port of the front cab hydraulic steering gear from the hydraulic pump outlet oil port through the priority valve, and then enters the upper chamber of the front axle steering cylinder through the L port of the front cab hydraulic steering gear through the second hydraulic-controlled reversing valve. The piston of the front axle steering cylinder moves downward, and at the same time, the hydraulic oil enters the R port of the hydraulic steering gear from the lower chamber of the front axle steering cylinder through the first empty reversing valve, thereby realizing the left steering operation of the front axle.

[0037] It should be noted that when the front axle is turned left or right during driving, the rear axle steering cylinder must lock the third hydraulically controlled reversing valve, the fourth hydraulically controlled reversing valve and the fifth hydraulically controlled reversing valve to prevent the rear axle from deviation during driving.

[0038] Furthermore, the principle of switching the centering mode oil circuit is to first switch to the front cab state or the rear cab state by switching the first three-way ball valve or the second three-way ball valve. After the cab state is selected, the corresponding manual reversing valve is selected (that is, when the front cab state is selected, the first manual reversing valve is selected accordingly, and when the rear cab state is selected, the second manual reversing valve is selected accordingly) to switch to the second gear. When it is the front cab state at this time, the first manual reversing valve is operated to switch to the second gear, the third hydraulically controlled reversing valve and the fourth hydraulically controlled reversing valve are opened, and the first hydraulically controlled reversing valve, the second hydraulically controlled reversing valve and the fifth hydraulically controlled reversing valve are closed. When the front cab hydraulic steering gear is operated to rotate clockwise, the front cab hydraulic steering gear feedback oil circuit LS enters the priority valve through the first shuttle valve, causing the priority valve main valve core to change direction. At this time, the hydraulic oil enters the P port of the front cab hydraulic steering gear through the priority valve from the hydraulic pump outlet oil, and then enters the lower chamber of the rear axle steering cylinder through the fourth hydraulic-controlled reversing valve from the R port of the front cab hydraulic steering gear, causing the piston of the rear axle steering cylinder to move upward. At the same time, the hydraulic oil enters the L port of the front cab hydraulic steering gear from the upper chamber of the rear axle steering cylinder through the third hydraulic-controlled reversing valve, thereby realizing the left rotation operation of the front axle and completing the centering of the rear axle steering cylinder.

[0039] Similarly, when the front cab hydraulic steering gear is operated to rotate counterclockwise, the front cab hydraulic steering gear feedback oil circuit LS enters the priority valve through the first shuttle valve, causing the priority valve main valve core to reverse. At this time, the hydraulic oil enters the P port of the front cab hydraulic steering gear through the priority valve from the hydraulic pump outlet oil, and then enters the upper chamber of the rear axle steering cylinder from the L port of the front cab hydraulic steering gear through the third hydraulic-controlled reversing valve, causing the piston of the rear axle steering cylinder to move downward. At the same time, the hydraulic oil enters the R port of the front cab hydraulic steering gear from the lower chamber of the rear axle steering cylinder through the fourth hydraulic-controlled reversing valve, thereby realizing the right rotation operation of the front axle and completing the centering of the rear axle steering cylinder.

[0040] Furthermore, the principle of switching the circling mode oil circuit is to first switch to the front cab state or the rear cab state by switching the first three-way ball valve or the second three-way ball valve. After the cab state is selected, the corresponding manual reversing valve is selected (that is, when the front cab state is selected, the first manual reversing valve is selected, and when the rear cab state is selected, the second manual reversing valve is selected) to switch to the third gear. When it is the front cab state, the first manual reversing valve is operated to switch to the third gear, the first hydraulically controlled reversing valve, the third hydraulically controlled reversing valve and the fifth hydraulically controlled reversing valve are opened, and the second hydraulically controlled reversing valve and the fourth hydraulically controlled reversing valve are closed. When the front cab hydraulic steering gear is operated to rotate clockwise, the feedback oil circuit LS of the front cab hydraulic steering gear enters the priority valve through the first shuttle valve, so that the main valve core of the priority valve is reversed. At this time, the hydraulic oil enters the P port of the front cab hydraulic steering gear from the hydraulic pump outlet through the priority valve, and then enters the lower chamber of the front axle steering cylinder through the first hydraulic-controlled reversing valve from the R port of the front cab hydraulic steering gear, and the piston of the front axle steering cylinder moves up. At the same time, the hydraulic oil enters the lower chamber of the rear axle steering cylinder from the upper chamber of the front axle steering cylinder through the fifth hydraulic-controlled reversing valve, and the piston of the rear axle steering cylinder moves up, and the hydraulic oil enters the L port of the front cab hydraulic steering gear from the upper chamber of the rear axle steering cylinder through the third hydraulic-controlled reversing valve, thereby realizing the clockwise rotation operation.

[0041] Similarly, when the front cab hydraulic steering gear is operated to rotate counterclockwise, the front cab hydraulic steering gear feedback oil circuit LS enters the priority valve through the first shuttle valve, causing the priority valve main valve core to reverse. At this time, the hydraulic oil enters the P port of the front cab hydraulic steering gear from the hydraulic pump outlet through the priority valve, and then enters the upper chamber of the front axle steering cylinder from the L port of the front cab hydraulic steering gear through the third hydraulic-controlled reversing valve, and the piston of the front axle steering cylinder moves downward. At the same time, the hydraulic oil enters the upper chamber of the rear axle steering cylinder from the lower chamber of the front axle steering cylinder through the fifth empty reversing valve, and the piston of the rear axle steering cylinder moves downward, and the hydraulic oil enters the R port of the front cab hydraulic steering gear from the lower chamber of the rear axle steering cylinder through the first hydraulic-controlled reversing valve, thereby realizing the counterclockwise rotation operation.

[0042] It should be noted that when performing a turning operation, the second hydraulically controlled reversing valve and the fourth hydraulically controlled reversing valve need to be locked to avoid inconsistency between the deflection angles of the front axle and the rear axle during the turning process, thereby avoiding tire slippage and excessive tire wear.

[0043] Furthermore, when it is in the rear cab state at this time, the first three-way ball valve or the second three-way ball valve is switched to the rear cab state, and then the second manual reversing valve is operated to switch to the first gear, the third hydraulically controlled reversing valve and the fourth hydraulically controlled reversing valve are opened, and the first hydraulically controlled reversing valve, the second hydraulically controlled reversing valve and the fifth hydraulically controlled reversing valve are closed, and the above-mentioned front cab steering principle is executed to perform left or right steering of the rear cab; the first three-way ball valve or the second three-way ball valve is switched to the rear cab state, and then the second manual reversing valve is operated to switch to the second gear, and the third hydraulically controlled reversing valve and the fourth hydraulically controlled reversing valve are opened. The first hydraulic control reversing valve and the second hydraulic control reversing valve are closed, and the third hydraulic control reversing valve, the fourth hydraulic control reversing valve and the fifth hydraulic control reversing valve are closed, and the front axle steering cylinder is centered in accordance with the above-mentioned front cab centering principle; the first three-way ball valve or the second three-way ball valve is switched to the rear cab state, and then the second manual reversing valve is operated to switch to the third gear, and the second hydraulic control reversing valve, the fourth hydraulic control reversing valve and the fifth hydraulic control reversing valve are opened, and the first hydraulic control reversing valve and the third hydraulic control reversing valve are closed, and the above-mentioned front cab turning principle is executed, and the rear cab hydraulic steering gear is operated to realize the turning. The oil circuit switching principle of the rear cab state and the front cab state is the same, and no further elaboration is made here.

[0044] It should be noted that when operating in the rear cab state, the first hydraulically controlled reversing valve, the second hydraulically controlled reversing valve and the fifth hydraulically controlled reversing valve need to be locked during the steering process to prevent the front axle from deviation during driving; the first hydraulically controlled reversing valve and the third hydraulically controlled reversing valve need to be locked during the turning process to avoid the deflection angle of the front axle being inconsistent with the deflection angle of the rear axle during the turning process, thereby avoiding tire slippage and excessive tire wear.

[0045] This embodiment proposes a method for switching the oil circuit of full hydraulically controlled two-way driving, which is applied to a full hydraulically controlled two-way driving system. By selecting a cab, according to the selected cab, the oil circuit is switched to the corresponding cab mode by controlling the three-way ball valve group, wherein the cab mode includes the front cab mode and the rear cab mode, and then according to the selected cab mode, the manual reversing valve gear is selected to switch the oil circuit of the driving mode, thereby completing the steering, centering and turning operations of the front cab and the steering, centering and turning operations of the rear cab. It is realized that one cab can operate the front cab state and the rear cab state at the same time, and the operator does not need to run back and forth in the cab, which makes the operation more convenient and the efficiency is effectively improved.

[0046] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0047] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A fully hydraulically controlled two-way driving system, characterized in that: It includes a front axle steering cylinder and a rear axle steering cylinder for performing steering actions, a front cab hydraulic steering gear and a rear cab hydraulic steering gear for controlling steering, a hydraulic pump for providing hydraulic oil, a filter for filtering the hydraulic oil provided by the hydraulic pump, a priority valve for controlling the flow of hydraulic oil, and a reversing valve group for oil circuit switching; The reversing valve group for oil circuit switching includes a first hydraulically controlled reversing valve, a second hydraulically controlled reversing valve, a third hydraulically controlled reversing valve, a fourth hydraulically controlled reversing valve, and a fifth hydraulically controlled reversing valve; the first hydraulically controlled reversing valve and the second hydraulically controlled reversing valve are connected in series with the front axle steering cylinder; the third hydraulically controlled reversing valve and the fourth hydraulically controlled reversing valve are connected in series with the rear axle steering cylinder; the fifth hydraulically controlled reversing valve is connected in series with the front axle steering cylinder and the rear axle steering cylinder, respectively, and the first hydraulically controlled reversing valve, the second hydraulically controlled reversing valve, the third hydraulically controlled reversing valve, the fourth hydraulically controlled reversing valve, and the fifth hydraulically controlled reversing valve all have a locking function; The reversing valve group for oil circuit switching also includes two manual reversing valves, which are respectively arranged in the front cab and the rear cab, and are connected in parallel. The two manual reversing valves each have three gears, and the two manual reversing valves are respectively connected to a control handle, and the control handle is used to control the manual reversing valve to switch gears; The reversing valve group for oil circuit switching also includes a three-way ball valve group, which includes a first three-way ball valve and a second three-way ball valve. The first three-way ball valve is used for switching the front cab state; the second three-way ball valve is used for switching the rear cab state.

2. A fully hydraulically controlled bidirectional driving system according to claim 1, characterized in that: It also includes an overflow valve for protecting the safety of the oil circuit, and the overflow valve is arranged at a position adjacent to the hydraulic pump.

3. A fully hydraulically controlled bidirectional driving system according to claim 1, characterized in that: It also includes a shuttle valve group for oil circuit selection, the shuttle valve group includes a first shuttle valve, a second shuttle valve and a third shuttle valve, the first shuttle valve is arranged in the front cab hydraulic steering gear and the rear cab hydraulic steering gear; the second shuttle valve is arranged in the oil circuit adjacent to the rear axle steering cylinder; the third shuttle valve is arranged in the oil circuit adjacent to the front axle steering cylinder.

4. A method for switching oil circuits for full hydraulically controlled bidirectional driving, characterized in that: A fully hydraulically controlled bidirectional driving system as described in claims 1-3, comprising: A cab is selected, and according to the selected cab, the oil circuit is switched to a corresponding cab mode by controlling a three-way ball valve group, wherein the cab mode includes a front cab mode and a rear cab mode; According to the selected cab mode, select the manual reversing valve gear to switch the oil circuit of the driving mode. Specifically, If the manual reversing valve is in the first gear, the steering mode oil circuit is switched; If the manual reversing valve is in the second gear, the centering mode oil circuit is switched; If the manual reversing valve is in the third gear, the circle mode oil circuit is switched.

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