A mechanical handle hydraulic steering valve, steering system and engineering machinery

Abstract

This invention discloses a mechanical handle hydraulic steering valve, a steering system, and engineering machinery. The mechanical handle hydraulic steering valve includes: an inlet P6 for connecting to a pilot oil source; an L6 port for parallel connection with the L port of the steering gear; an R6 port for parallel connection with the R port of the steering gear; and a handle for driving the left and right directional valves to switch directions. Inlet P6 is connected to the inlet of the left and right directional valves, the outlet of the left directional valve is connected to the L6 port, and the outlet of the right directional valve is connected to the R6 port. The return ports of the left and right directional valves are connected to an oil tank. This invention enables the main unit to steer by controlling the flow amplification valve with a handle, thereby reducing the operator's workload.

Description

Technical Field

[0001] This invention belongs to the field of engineering machinery technology, specifically relating to a mechanical handle hydraulic steering valve, steering system, and engineering machinery. Background Technology

[0002] In existing technologies, the steering systems of construction machinery such as loaders, bulldozers, and graders are mostly fully hydraulic steering systems controlled by a steering wheel. During operation, in addition to using the handles for normal work, the operator must constantly use the steering wheel to control the vehicle's direction. When the vehicle is under heavy load, the steering wheel becomes heavy, inconvenient to operate, and control is not timely, resulting in poor safety, high operator workload, and low productivity. Furthermore, existing steering handles are mostly pressure-type mechanical handle hydraulic steering valves, outputting a pressure value. The flow amplification valve requires a continuous and stable flow output to create a pressure difference across the main valve stem for reversing. Pressure-type mechanical handle hydraulic steering valves cannot drive the flow amplification valve to achieve steering of the main unit. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a mechanical handle hydraulic steering valve, steering system, and engineering machinery. The main unit can be steered by controlling the flow amplification valve through the handle, thereby reducing the operator's workload.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, a mechanical handle hydraulic steering valve is provided, comprising: an inlet P6 for connecting to a pilot oil source; an L6 port for connecting in parallel with the L port of the steering gear; an R6 port for connecting in parallel with the R port of the steering gear; a handle for driving the left and right directional valves to switch directions; the inlet P6 is connected to the inlet of the left and right directional valves, the outlet of the left directional valve is connected to the L6 port, and the outlet of the right directional valve is connected to the R6 port; the return ports of the left and right directional valves are connected to an oil tank.

[0006] Furthermore, it also includes a logic valve for prioritizing steering control, with the outlet of the left directional valve and the outlet of the right directional valve connected to port L6 and port R6 respectively via the logic valve; the spring chamber of the logic valve is connected to the oil tank and the control end is connected to port LS of the steering gear.

[0007] Furthermore, the return port of the left directional valve, the return port of the right directional valve, and the spring chamber of the logic valve are all connected to the oil tank through a back pressure valve.

[0008] Furthermore, it also includes a compensation valve, the inlet of which is connected to inlet P6, the outlet of which is connected to the inlet of the left directional valve and the inlet of the right directional valve respectively, the spring chamber of which is connected to the outlet of shuttle valve one, the inlet one of shuttle valve one is connected to the return port of the left directional valve, and the inlet two of shuttle valve one is connected to the return port of the right directional valve.

[0009] In a second aspect, a steering system is provided, the steering system being configured with the mechanical handle hydraulic steering valve described in the first aspect.

[0010] Furthermore, the steering gear inlet P is connected to the pilot oil source, the steering gear L port is connected to the flow amplification valve L4 port through limit valve one, and the steering gear R port is connected to the flow amplification valve R4 port through limit valve two; the flow amplification valve inlet P4 is connected to the oil source, and the working port is connected to the steering cylinder.

[0011] Furthermore, the flow amplification valve includes a steering priority valve. The inlet of the steering priority valve is connected to the inlet P4 of the flow amplification valve, and the outlet of the steering priority valve is connected to the steering cylinder through a reversing valve. The control end of the reversing valve is connected to the R4 port and L4 port of the flow amplification valve, respectively. The shuttle valve 44 feeds back the pressure of the steering cylinder 7 to the spring chamber of the steering priority valve and the inlet of the relief valve to realize the steering priority function of the flow amplification valve 4 and to prevent pressure buildup when the steering cylinder reaches the end of its stroke.

[0012] Furthermore, when steering using the steering gear, the pilot oil output from the pilot oil source enters the control terminal of the logic valve through the LS port of the steering gear. The logic valve switches to the cut-off position, and the hydraulic steering valve of the mechanical handle is in a disabled state. If turning right, the pilot oil output from the pilot oil source enters the R4 port of the flow amplification valve through the R port of the steering gear. The hydraulic oil output from the oil source enters the steering cylinder through the flow amplification valve, realizing right steering. If turning left, the pilot oil output from the pilot oil source enters the L4 port of the flow amplification valve through the L port of the steering gear. The hydraulic oil output from the oil source enters the steering cylinder through the flow amplification valve, realizing left steering.

[0013] Furthermore, when using the lever to operate the hydraulic steering valve of the mechanical lever, if turning right, the pilot oil output from the pilot oil source enters the R4 port of the flow amplification valve through the inlet P6 of the hydraulic steering valve, the right directional valve, the logic valve, and the R6 port of the hydraulic steering valve of the mechanical lever. The hydraulic oil in the L4 port of the flow amplification valve flows into the oil tank through the logic valve and the left directional valve. The directional valve in the flow amplification valve opens, and the hydraulic oil output from the oil source enters the steering cylinder through the flow amplification valve, realizing right steering. If turning left, the pilot oil output from the pilot oil source enters the L4 port of the flow amplification valve through the inlet P6 of the hydraulic steering valve, the left directional valve, the logic valve, and the L6 port of the hydraulic steering valve of the mechanical lever. The hydraulic oil in the R4 port of the flow amplification valve flows into the oil tank through the logic valve and the right directional valve. The directional valve in the flow amplification valve opens, and the hydraulic oil output from the oil source enters the steering cylinder through the flow amplification valve, realizing left steering.

[0014] Thirdly, a piece of engineering machinery is provided, which is equipped with the mechanical handle hydraulic steering valve described in the first aspect or the steering system described in the second aspect.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0016] (1) The present invention uses an inlet P6 for connecting the pilot oil source, an L6 port for parallel connection with the L port of the steering gear, an R6 port for parallel connection with the R port of the steering gear, and a handle for driving the left and right directional valves to switch. The inlet P6 is connected to the inlet of the left directional valve and the inlet of the right directional valve. The outlet of the left directional valve is connected to the L6 port, and the outlet of the right directional valve is connected to the R6 port. The return ports of the left and right directional valves are connected to the oil tank. This invention achieves parallel connection with the steering wheel system, and each of them can independently control the steering of the main unit. When performing complex operations, the steering can be controlled by the handle, reducing the labor intensity of the operator. It has the characteristics of reliable performance and convenient operation, which reduces the labor intensity of the operator and improves the work efficiency.

[0017] (2) The present invention has a built-in logic control valve in the hydraulic steering valve of the mechanical handle, so that the steering wheel always takes priority over the steering control of the handle, so that in a certain emergency or during high-speed driving, the steering wheel can be directly used to take over the steering of the main unit.

[0018] (3) This invention relates to a flow-type mechanical handle hydraulic directional valve. The flow-type mechanical handle hydraulic directional valve uses a mechanical handle to directly control the valve core displacement, outputs a continuous and stable flow, and generates a pressure difference at both ends of the main valve stem of the flow amplification valve to achieve directional switching, thereby controlling the main machine to turn. The mechanical handle hydraulic directional valve is flexible, convenient, reliable, safe and stable, has a fast response speed, and no hysteresis. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a steering system provided in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the mechanical handle hydraulic steering valve in an embodiment of the present invention, wherein (a) is a cross-section. Figure 1 (b) is a cross-section Figure 2 (c) is a cross-section Figure 3 (d) is section view four;

[0021] Figure 3 This is a schematic diagram of the principle of the hydraulic steering valve of the mechanical handle in an embodiment of the present invention;

[0022] In the diagram: 1. Pilot oil source; 2. Steering gear; 4. Flow amplification valve; 41. Steering priority valve; 42. Relief valve; 43. Reversing valve; 44. Shuttle valve II; 5. Oil source; 6. Mechanical handle hydraulic steering valve; 61. Compensation valve; 62. Back pressure valve; 63. Shuttle valve I; 64. Left reversing valve; 65. Right reversing valve; 66. Logic valve; 7. Steering cylinder; 8. Handle; 9. Sealing end cap; 10. Push rod; 11. Adjusting screw; 12. Handle seat; 13. Handle bracket; 14. Reversing spring; 15. Compensation valve spring; 16. Logic control valve spring; 17. Valve body; 18. Limit valve I; 19. Limit valve II; 23~35. Internal oil passage I~Internal oil passage thirteen. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0024] Example 1

[0025] like Figures 1-3 As shown, a mechanical handle hydraulic steering valve includes: an inlet P6 disposed on a valve body 17 for connecting to a pilot oil source 1, an L6 port for parallel connection with the L port of a steering gear 2, an R6 port for parallel connection with the R port of a steering gear 2, and a handle 8 for driving the left directional valve 64 and the right directional valve 65 to switch directions; the inlet P6 is connected to the inlet of the left directional valve 64 and the inlet of the right directional valve 65, the outlet of the left directional valve 64 is connected to the L6 port, and the outlet of the right directional valve 65 is connected to the R6 port; the return ports of the left directional valve 64 and the right directional valve 65 are connected to an oil tank. It also includes a sealing end cap 9, a push rod 10, an adjusting screw 11, a handle seat 12, a handle bracket 13, a reversing spring 14, a compensation valve spring 15, a logic control valve spring 16, and a valve body 17.

[0026] It also includes a logic valve 66 for prioritizing the control of the steering gear 2. The outlet of the left directional valve 64 and the outlet of the right directional valve 65 are connected to the L6 port and R6 port respectively through the logic valve 66. The spring chamber of the logic valve 66 is connected to the oil tank and the control end is connected to the LS port of the steering gear 2.

[0027] The return port of the left directional valve 64, the return port of the right directional valve 65, and the spring chamber of the logic valve 66 are all connected to the oil tank through the back pressure valve 62.

[0028] It also includes a compensation valve 61, the inlet of which is connected to inlet P6, the outlet of which is connected to the inlet of the left directional valve 64 and the inlet of the right directional valve 65 respectively, the spring chamber of the compensation valve 61 is connected to the outlet of shuttle valve 63, the inlet of shuttle valve 63 is connected to the return port of the left directional valve 64, and the inlet of shuttle valve 63 is connected to the return port of the right directional valve 65.

[0029] When the handle 8 swings to the right, the pilot oil output from the pilot oil source 1 flows from the inlet P6 through the internal oil passage 1 23, and after passing through the compensation valve 61, a portion of the pilot oil passes through the internal oil passage 2 24 and acts on the non-spring side of the compensation valve 61. The pilot oil passes through the internal oil passage 3 25 and the internal oil passage 5 27, through the right directional valve 65, the internal oil passage 9 31, and the logic valve 66 to the R6 port and flows to the flow amplification valve 4. A portion of the pilot oil passes through the right directional valve 65, the internal oil passage 7 29, the shuttle valve 1 63, and the internal oil passage 4 26 and acts on the spring chamber of the compensation valve 61 to ensure that the pressure difference on both sides of the right directional valve 65 is constant. The return oil from the flow amplification valve 4 flows through the L6 port through the logic valve 66, the internal oil passage 8 30, the left directional valve 64, the internal oil passage 12 34, and the back pressure valve 62, returning to the T6 port and finally back to the oil tank.

[0030] When handle 8 swings to the left, the principle is the same as when handle 8 swings to the right. The pilot oil output from pilot oil source 1 flows from inlet P6 through internal oil passage 1 23, and after passing through compensation valve 61, part of the pilot oil acts on the non-spring side of compensation valve 61 through internal oil passage 2 24. The pilot oil flows through internal oil passage 3 25, internal oil passage 5 27, through left reversing valve 64, internal oil passage 8 30, logic valve 66 to L6 port and flows to flow amplification valve 4. Part of the pilot oil acts on the spring chamber of compensation valve 61 through left reversing valve 64, internal oil passage 6 28, shuttle valve 1 63, internal oil passage 4 26 to ensure that the pressure difference on both sides of left reversing valve 64 is constant. The return oil from flow amplification valve 4 flows through R6 port through logic valve 66, internal oil passage 9 31, right reversing valve 65, internal oil passage 13 35, back pressure valve 62, back to T6 port, and finally back to the oil tank.

[0031] When control oil flows through port C of the mechanical handle hydraulic steering valve 6 and acts on the control end (non-spring chamber) of the logic valve 66 via internal oil passage 32, the spring chamber of the logic valve 66 is connected to the oil tank through internal oil passage 33, internal oil passage 34, and back pressure valve 62. The logic valve 66 moves to the left, cutting off the oil passage between the left reversing valve 64, the right reversing valve 65, port L6, and port R6. The pilot oil source cannot flow to both ends of the flow amplification valve 4, causing the mechanical handle hydraulic steering valve to malfunction and become disabled.

[0032] Example 2

[0033] Based on the mechanical handle hydraulic steering valve described in Embodiment 1, this embodiment provides a steering system equipped with the mechanical handle hydraulic steering valve 6 described in Embodiment 1. The inlet P of the steering gear 2 is connected to the pilot oil source 1; the L port of the steering gear 2 is connected to the L4 port of the flow amplification valve 4 via limit valve 18; and the R port of the steering gear 2 is connected to the R4 port of the flow amplification valve 4 via limit valve 2 19. The inlet P4 of the flow amplification valve 4 is connected to the oil source 5, and its working port is connected to the steering cylinder 7. The flow amplification valve 4 includes a steering priority valve 41. The inlet of the steering priority valve 41 is connected to the inlet P4 of the flow amplification valve 4, and the outlet of the steering priority valve 41 is connected to the steering cylinder 7 via a reversing valve 43. The control end of the reversing valve 43 is connected to the R4 port and the L4 port of the flow amplification valve 4, respectively.

[0034] The pilot oil output from the pilot oil source 1 is connected to the inlet P6 of the steering gear 2 and the mechanical handle hydraulic steering valve 6 respectively. The L port of the steering gear 2 is connected in parallel with the L6 port of the mechanical handle hydraulic steering valve 6. Then, the limit valve 18 is connected in series with the L4 port of the reversing valve 43 in the flow amplification valve 4. The R port of the steering gear 2 is connected in parallel with the R6 port of the mechanical handle hydraulic steering valve 6. Then, the limit valve 2 19 is connected in series with the R4 port of the reversing valve 43 in the flow amplification valve 4. The hydraulic oil output from the oil source 5 enters the inlet P4 of the flow amplification valve 4. The CL port and CR port of the flow amplification valve 4 are connected to the steering cylinder 7.

[0035] When steering gear 2 is engaged and hydraulic steering valve 6 is disengaged, pilot oil from pilot oil source 1 enters steering gear 2. The pilot oil is controlled by left or right steering gear 2 to enter port L or port R. Taking right steering as an example, during steering gear 2 rotation, a portion of the pilot oil flows through port LS of the steering gear and through port C of logic valve 66, pushing logic valve 66 to the left, closing the valve port, and cutting off the oil supply. Simultaneously, the pilot oil enters limit valve 19 through port R of steering gear 2, and then reaches port R4 of directional valve 43. The hydraulic oil in port L4 of directional valve 43 returns to port L of steering gear 2 through limit valve 18. Finally, the oil returns to the oil tank; the pilot oil flowing through the two ends of the reversing valve 43 generates a pressure difference, opening the reversing valve 43. The hydraulic oil output from the oil source 5 enters the steering cylinder 7 through the steering priority valve 41 and the reversing valve 43, realizing the steering of the main unit. The pressure of the steering cylinder 7 is fed back to the spring chamber of the steering priority valve 41 through the shuttle valve 2 44, realizing the steering priority function of the flow amplification valve 4, and is connected in parallel with the relief valve 42 to prevent pressure buildup when the steering cylinder 7 reaches the end of its stroke. The R port of the steering gear 2 is also connected to the R6 port of the mechanical handle hydraulic steering valve 6. Since the logic valve 66 is closed, this oil circuit is cut off, and the mechanical handle hydraulic steering valve 6 is in a disabled state. The working principle of the steering gear 2 when turning left is the same as that when the steering gear 2 turns right.

[0036] When the mechanical handle hydraulic steering valve 6 is working and the steering gear 2 is not working, the hydraulic oil output from the pilot oil source 1 enters the mechanical handle hydraulic steering valve 6. Taking the handle 8 swinging to the right as an example, when the handle 8 swings to the right, the right reversing valve 65 is in the left position. The pilot oil provided by the pilot oil source 1 passes through the compensation valve 61, the right reversing valve 65, the logic valve 66, and the second limit valve 19, and finally reaches the R4 port of the reversing valve 43. The hydraulic oil in the L4 port of the reversing valve 43 passes through the first limit valve 18 and returns to the L6 port of the mechanical handle hydraulic steering valve 6, the logic valve 66, and the left reversing valve. Valve 64, back pressure valve 62, and then return to the oil tank. The pressure difference generated between port R4 and port L4 of directional valve 43 opens directional valve 43. The hydraulic oil output from oil source 5 passes through steering priority valve 41 and directional valve 43 and enters steering cylinder 7 to realize the steering of the main unit. The pressure of steering cylinder 7 is fed back to the spring chamber of steering priority valve 41 through shuttle valve 2 44 to realize the steering priority function of flow amplification valve 4 and is connected in parallel with relief valve 42 to prevent pressure buildup when steering cylinder 7 reaches the stroke end point. The working principle of handle 8 swinging to the left is the same as that of handle 8 swinging to the right.

[0037] The steering gear 2 operates on the principle of priority control. When the mechanical handle hydraulic steering valve 6 is working and controlling the entire steering system, turning the steering gear 2 causes a portion of the pilot oil inside the steering gear 2 to flow through the LS port of the steering gear 2 and through the C port of the logic valve 66, pushing the logic valve 66 to the left and closing the valve port. This cuts off the oil supply to the L6 and R6 ports of the mechanical handle hydraulic steering valve 6, causing the mechanical handle hydraulic steering valve 6 to lose control. At this time, the steering gear 2 takes priority control over the entire steering system.

[0038] This invention relates to a mechanical handle hydraulic steering valve connected in parallel with a steering system controlled by a steering gear. Both the mechanical handle hydraulic steering valve and the steering gear can independently output pilot oil to control the displacement of the flow amplification valve spool, thereby controlling the steering cylinder and achieving vehicle steering. The mechanical handle hydraulic steering valve has a built-in logic valve. By controlling the logic valve, steering gear control is prioritized. In emergencies or when the vehicle is traveling at high speed, the steering gear has absolute priority control of steering. At this time, the mechanical handle hydraulic steering valve is cut off and cannot control the steering system. This steering system is reliable, easy to operate, reduces the operator's labor intensity, and improves work efficiency. It is a dual-steering hydraulic system containing a flow-type mechanical handle hydraulic steering valve. During operation, the operator can control the flow amplification valve spool by outputting pilot oil through the mechanical handle hydraulic steering valve, thereby controlling the steering cylinder to achieve steering. Continuous steering wheel operation is not required, thus reducing the operator's labor intensity. Operation is convenient, fast, safe, and reliable, improving work efficiency. This flow-type mechanical handle hydraulic steering valve uses a mechanical handle to directly control the valve spool displacement. In addition to outputting a stable and continuous flow, it has a fast response speed and no hysteresis.

[0039] Example 3

[0040] Based on the mechanical handle hydraulic steering valve described in Embodiment 1 and the steering system described in Embodiment 2, this embodiment provides a piece of construction machinery (such as a loader, bulldozer, grader, etc.), which is equipped with the mechanical handle hydraulic steering valve described in Embodiment 1 or the steering system described in Embodiment 2.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A mechanical handle hydraulic steering valve, characterized in that, include: Inlet P6 is used to connect the pilot oil source (1); L6 port is used to connect in parallel with L port of steering gear (2); R6 port is used to connect in parallel with R port of steering gear (2); Handle (8) for driving the left directional valve (64) and right directional valve (65) to switch directions; The inlet P6 is connected to the inlet of the left directional valve (64) and the inlet of the right directional valve (65). The outlet of the left directional valve (64) is connected to port L6, and the outlet of the right directional valve (65) is connected to port R6. The return ports of the left directional valve (64) and the right directional valve (65) are connected to the oil tank. It also includes a logic valve (66) for prioritizing the control of the steering gear (2). The outlet of the left directional valve (64) and the outlet of the right directional valve (65) are connected to the L6 port and R6 port respectively through the logic valve (66). The spring chamber of the logic valve (66) is connected to the oil tank and the control end is connected to the LS port of the steering gear (2).

2. The mechanical handle hydraulic steering valve according to claim 1, characterized in that, The return port of the left reversing valve (64), the return port of the right reversing valve (65), and the spring chamber of the logic valve (66) are all connected to the oil tank through the back pressure valve (62).

3. The mechanical handle hydraulic steering valve according to claim 1, characterized in that, It also includes a compensation valve (61), the inlet of the compensation valve (61) is connected to the inlet P6, the outlet of the compensation valve (61) is connected to the inlet of the left directional valve (64) and the inlet of the right directional valve (65) respectively, the spring cavity of the compensation valve (61) is connected to the outlet of shuttle valve one (63), the inlet one of the shuttle valve one (63) is connected to the return port of the left directional valve (64), and the inlet two of the shuttle valve one (63) is connected to the return port of the right directional valve (65).

4. A steering system, characterized in that, The steering system is equipped with a mechanical handle hydraulic steering valve (6) as described in any one of claims 1 to 3.

5. The steering system according to claim 4, characterized in that, The inlet P of the steering gear (2) is connected to the pilot oil source (1), the L port of the steering gear (2) is connected to the L4 port of the flow amplification valve (4) through the limit valve one (18), and the R port of the steering gear (2) is connected to the R4 port of the flow amplification valve (4) through the limit valve two (19); the inlet P4 of the flow amplification valve (4) is connected to the oil source (5), and the working port is connected to the steering cylinder (7).

6. The steering system according to claim 5, characterized in that, The flow amplification valve (4) includes a steering priority valve (41). The inlet of the steering priority valve (41) is connected to the inlet P4 of the flow amplification valve (4). The outlet of the steering priority valve (41) is connected to the steering cylinder (7) through the reversing valve (43). The control end of the reversing valve (43) is connected to the R4 port and L4 port of the flow amplification valve (4) respectively. The shuttle valve 44 feeds back the pressure of the steering cylinder 7 to the spring chamber of the steering priority valve (41) and the inlet of the relief valve (42) to realize the steering priority function of the flow amplification valve 4 and to prevent the steering cylinder (7) from accumulating pressure when it reaches the end of its stroke.

7. The steering system according to claim 5, characterized in that, When steering is performed using steering gear (2), the pilot oil output from pilot oil source (1) enters the control terminal of logic valve (66) through the LS port of steering gear (2), and logic valve (66) switches to the cut-off position, and mechanical handle hydraulic steering valve (6) is in a disabled state. If turning right, the pilot oil output from the pilot oil source (1) enters the R4 port of the flow amplification valve (4) through the R port of the steering gear (2), and the hydraulic oil output from the oil source (5) enters the steering cylinder (7) through the flow amplification valve (4) to achieve right turning; If turning left, the pilot oil output from the pilot oil source (1) enters the L4 port of the flow amplification valve (4) through the L port of the steering gear (2), and the hydraulic oil output from the oil source (5) enters the steering cylinder (7) through the flow amplification valve (4) to achieve left turning.

8. The steering system according to claim 5, characterized in that, When the mechanical handle (8) is used to operate the hydraulic steering valve (6) to turn, If turning right, the pilot oil output from the pilot oil source (1) enters the R4 port of the flow amplification valve (4) through the inlet P6 of the mechanical handle hydraulic steering valve (6), the right reversing valve (65), the logic valve (66), and the R6 port of the mechanical handle hydraulic steering valve (6). The hydraulic oil in the L4 port of the flow amplification valve (4) flows into the oil tank through the logic valve (66) and the left reversing valve (64). The reversing valve (43) in the flow amplification valve (4) opens. The hydraulic oil output from the oil source (5) enters the steering cylinder (7) through the flow amplification valve (4), thus realizing right turning. If turning left, the pilot oil output from the pilot oil source (1) enters the L4 port of the flow amplification valve (4) through the inlet P6 of the mechanical handle hydraulic steering valve (6), the left reversing valve (64), the logic valve (66), and the L6 port of the mechanical handle hydraulic steering valve (6). The hydraulic oil in the R4 port of the flow amplification valve (4) flows into the oil tank through the logic valve (66) and the right reversing valve (65). The reversing valve (43) in the flow amplification valve (4) is opened. The hydraulic oil output from the oil source (5) enters the steering cylinder (7) through the flow amplification valve (4), thus realizing left turning.

9. An engineering machinery, characterized in that, The engineering machinery is equipped with a mechanical handle hydraulic steering valve (6) as described in any one of claims 1 to 3.

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