Steering brake system and engineering machine

Abstract

The application discloses a steering brake system and engineering machinery, the steering brake system comprises a gear pump, the oil outlet of the gear pump is connected with the P port of a priority valve, the EF port of the priority valve is combined with a working system, the CF port of the priority valve is connected with the P port of a steering gear and the P port of a signal control valve respectively, the Ls port of the steering gear is connected with the Ls2 port of the signal control valve, the Ls port of the priority valve is connected with the Ls1 port of the signal control valve, the A port of the signal control valve and the P port of a brake valve are connected with an accumulator respectively, the steering gear is used for controlling a steering oil cylinder to realize steering, the signal control valve is used for controlling parking brake, and the brake valve is used for controlling service brake. The application realizes that working, steering and braking share an oil source, the intermittent working characteristics of the brake system are utilized to avoid mutual interference of the working and the steering when they work simultaneously, and steering and braking performances are ensured.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of engineering machinery, and particularly relates to a steering brake system and engineering machinery. BACKGROUND

[0002] In the prior art, the steering system and the brake system are usually independent pump sources, and it is difficult to arrange the pump sources when the space of part of engineering machinery products is limited and the number of system pump sources is too large. Therefore, the design concept of sharing oil sources has been the development direction of the hydraulic system of engineering machinery, and is of great significance to the compactness of the hydraulic system.

[0003] The brake system is intermittent, and independent pump sources undoubtedly cause the loss of system energy consumption. Therefore, sharing oil sources is also of great significance to energy saving and emission reduction. The current steering and brake shared oil source only simply integrates the brake system into the steering system, which affects the steering performance when the brake system works, and seriously affects the work efficiency of customers. SUMMARY

[0004] To solve the problems in the prior art, the present application provides a steering brake system and engineering machinery, which realizes the sharing of oil sources for work, steering and braking, avoids the mutual interference of the two when they work at the same time by using the intermittent working characteristics of the brake system, and guarantees the steering and braking performance.

[0005] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0006] In a first aspect, a steering brake system is provided, comprising: a gear pump, an oil outlet of the gear pump being connected with a P port of a priority valve; an EF port of the priority valve being combined with a work system; a CF port of the priority valve being connected with a P port of a steering gear and a P port of a signal control valve respectively; an Ls port of the steering gear being connected with an Ls2 port of the signal control valve; an Ls port of the priority valve being connected with an Ls1 port of the signal control valve; an A port of the signal control valve and a P port of a brake valve being connected with an accumulator respectively; the steering gear being used for controlling a steering oil cylinder to realize steering; the signal control valve being used for controlling parking brake; and the brake valve being used for controlling service brake.

[0007] Further, the signal control valve comprises a cut-off valve core, a liquid charging valve core and an overflow valve, an oil inlet of the cut-off valve core being connected with an Ls1 port of the signal control valve; a liquid control end of the cut-off valve core being connected with an Ls2 port of the signal control valve; a spring cavity of the cut-off valve core being connected with a T port of the signal control valve; an oil outlet of the cut-off valve core being connected with the T port of the signal control valve through the overflow valve; the P port of the signal control valve being connected with an oil inlet of the liquid charging valve core, a liquid control end of the liquid charging valve core, an A port of the signal control valve and an SW port of the signal control valve respectively, the SW port of the signal control valve being connected with parking brake; and an oil outlet of the liquid charging valve core being connected with the T port of the signal control valve through the overflow valve.

[0008] Furthermore, when the whole machine is not in operation, the shut-off valve core is in the right position, the Ls1 port of the signal control valve and the Ls2 port of the signal control valve are not connected, and the Ls port of the priority valve passes through the shut-off valve core and the filling valve core to the T port of the signal control valve. At this time, the priority valve is in the right position, and the P port of the priority valve is connected to the EF port.

[0009] Furthermore, when the pressure of the accumulator is lower than the minimum set value and no change is made, the Ls port of the priority valve is connected to the accumulator through the cut-off valve core and the filling valve core, and the priority valve is switched to the left position, so that the pressure of the accumulator is increased to the maximum set value.

[0010] Furthermore, when the machine is turned, the pressure at port Ls2 of the signal control valve is higher than the set value, and port Ls1 of the signal control valve is connected to port Ls2 of the signal control valve; the pressure at port CF of the priority valve acts on the hydraulic control end of the cut-off valve core through the diverter, causing the cut-off valve core to switch directions.

[0011] Furthermore, the LS port of the priority valve is provided with throttling orifices D1 and D2, and the switching pressure p of the shut-off valve core of the signal control valve satisfies the following conditions:

[0012]

[0013] Where Δp is the switching pressure of the priority valve core, A1 is the area of ​​the throttle orifice D1, and A2 is the area of ​​the throttle orifice D2.

[0014] Furthermore, the relief valve is used to limit the maximum braking pressure. When the pressure of the accumulator reaches the opening pressure of the relief valve, the Ls port of the priority valve is connected to the Ls1 port of the signal control valve and the oil returns through the relief valve. At this time, the priority valve is in the right position, and the flow of the gear pump is discharged to the EF port through the high pressure of the priority valve.

[0015] Furthermore, the signal control valve is provided with a throttling orifice D3, which is used to control the liquid flow rate of the accumulator.

[0016] In a second aspect, there is a piece of engineering machinery equipped with the steering and braking system described in the first aspect.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention connects the oil outlet of the gear pump to the P port of the priority valve; the EF port of the priority valve merges with the working system; the CF port of the priority valve is connected to the P port of the steering gear and the P port of the signal control valve respectively; the Ls port of the steering gear is connected to the Ls2 port of the signal control valve; the Ls port of the priority valve is connected to the Ls1 port of the signal control valve; the A port of the signal control valve and the P port of the brake valve are connected to the accumulator respectively; the steering gear is used to control the steering cylinder to achieve steering; the signal control valve is used to control the parking brake; the brake valve is used to control the service brake; the working, steering and braking share the same oil source, and the intermittent working characteristics of the braking system avoid mutual interference when the two work simultaneously, thus ensuring steering and braking performance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the working principle of a steering braking system provided in an embodiment of the present invention;

[0019] Figure 2 yes Figure 1 Schematic diagram of the working principle of the signal control valve;

[0020] In the diagram: 1. Gear pump; 2. Priority valve; 3. Steering gear; 4. Signal control valve; 5. Brake valve; 6. Accumulator; 7. Shut-off valve core; 8. Filling valve core; 9. Relief valve. Detailed Implementation

[0021] 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.

[0022] Example 1:

[0023] like Figure 1 , Figure 2 As shown, a steering braking system includes: a gear pump 1, a priority valve 2, a steering gear 3, a signal control valve 4, a brake valve 5, an accumulator 6, a cut-off valve core 7, a filling valve core 8, and a relief valve 9.

[0024] The oil outlet of gear pump 1 is connected to the P port of priority valve 2; the EF port of priority valve 2 merges with the working system; the CF port of priority valve 2 is connected to the P port of steering gear 3 and the P port of signal control valve 4 respectively; the Ls port of steering gear 3 is connected to the Ls2 port of signal control valve 4; the Ls port of priority valve 2 is connected to the Ls1 port of signal control valve 4; the A port of signal control valve and the P port of brake valve are connected to accumulator 6 respectively; the L and R ports of steering gear 3 are connected to steering cylinder to control steering cylinder to achieve steering; signal control valve 4 controls parking brake through SW port; brake valve 5 is used to control service brake.

[0025] The signal control valve 4 includes a shut-off valve core 7, a filling valve core 8, and a relief valve 9. The Ls1 port of the signal control valve 4 is connected to the oil inlet of the shut-off valve core 7; the Ls2 port of the signal control valve 4 is connected to the hydraulic control end of the shut-off valve core 7; the spring cavity of the shut-off valve core 7 is connected to the T port of the signal control valve 4; the oil outlet of the shut-off valve core 7 is connected to the T port of the signal control valve 4 via the relief valve 9; the P port of the signal control valve 4 is connected to the oil inlet of the filling valve core 8, the hydraulic control end of the filling valve core 8, the A port of the signal control valve, and the SW port of the signal control valve 4, respectively; the SW port of the signal control valve is connected to the parking brake; the oil outlet of the filling valve core 8 is connected to the T port of the signal control valve 4 via the relief valve 9. The T port is used for oil return.

[0026] When the machine is not in operation, the shut-off valve core 7 is in the right position. At this time, Ls1 and Ls2 are not connected, and Ls1 is connected to the oil circuit of the filling valve core 8. When the machine turns, the Ls1 port is connected to the Ls port of the priority valve 2, and the oil circuit of the Ls1 port to the filling valve core 8 is cut off.

[0027] The following is a principle analysis of the machine under different working conditions:

[0028] The LS port of the priority valve (2) is equipped with throttling orifices D1 and D2. When the whole machine is in standby mode, part of the oil from the gear pump 1 passes through the P port to the CF port, then enters the throttling orifices D1 and D2, and then enters the Ls1. After passing through the shut-off valve core 7 and the filling valve core 8, the oil finally returns. When passing through the throttling orifice D1, Δp is generated, causing the priority valve to switch to the right position. Therefore, the pressure at the CF port is ≥ Δp.

[0029] When the pressure of accumulator 6 is lower than the minimum set value, the filling valve core 8 switches to the right position. At this time, Ls1 is connected to accumulator 6, and the pressure of accumulator 6 acts on the Ls port of priority valve 2, causing priority valve 2 to be in the left position. At this time, the pump port pressure increases to fill the pump. When the pressure of accumulator 6 rises to the maximum set value, the filling valve core 8 switches to the left position, Ls1 is connected to the T port, the pressure of the P port of signal control valve 4 decreases, and the system returns to the standby state.

[0030] When the machine is turning, the P port of the steering gear 3 is connected to the Ls port. Therefore, the pressure of the CF port of the priority valve 2 is applied to the hydraulic control end of the cut-off valve core 7 through the Ls2 port of the signal control valve 4, causing the cut-off valve core 7 to switch to the left position. At this time, the load pressure of the L and R ports of the steering gear 3 is applied to the valve core control chamber of the priority valve 2 through the Ls port of the steering gear 3 to the Ls2 port of the signal control valve 4 - Ls1 to the Ls port of the priority valve 2, causing the priority valve 2 to be in the left position. At this time, the pump port pressure increases to complete the steering action. When the steering stops, the Ls2 port of the signal control valve 4 is connected to the T port of the steering gear 3, the cut-off valve core 7 switches to the right position, and the Ls port signal of the priority valve 2 is reconnected to the T port of the filling valve core 8, and the machine returns to the standby state.

[0031] When the machine is turning, the pressure of the accumulator 6 is lower than the minimum set value. At this time, the pressure at port Ls2 of the signal control valve 4 causes the shut-off valve core to be in the left position. Therefore, the accumulator 6 and port Ls1 of the signal control valve 4 are cut off. No liquid filling is performed at this time. After the turning action is completed, the shut-off valve core is switched back to the right position to complete the liquid filling.

[0032] When the machine is being filled with liquid and the steering is performed, the pressure at port Ls2 of the signal control valve 4 increases, causing the cut-off valve core 7 to switch to the left position. The accumulator 6 is disconnected from port Ls1 of the signal control valve 4, the liquid filling stops, and the steering operation begins normally. This continues until the steering operation is completed and the cut-off valve core 7 returns to the right position. The oil circuit of port Ls1 of the signal control valve 4 and the liquid filling valve core 8 are connected. At this time, the liquid filling is judged to see if the pressure of the accumulator 6 is lower than the minimum set value. If it is higher than the minimum set value, the liquid filling will stop. If it is still lower than the minimum set value, the liquid filling will start again.

[0033] Meanwhile, when the entire machine is in standby mode, the pressure at port P of the steering gear 3 should be sufficient to cause the shut-off valve core 7 to reverse. Therefore, the reversing pressure p of the shut-off valve core 7 should meet the following conditions:

[0034]

[0035] Where Δp is the switching pressure of the priority valve core, A1 is the area of ​​the throttle orifice D1, and A2 is the area of ​​the throttle orifice D2.

[0036] When the filling valve core 8 is stuck, the filling cannot be stopped when the pressure of the accumulator 6 is higher than the set value. When the pressure rises to the point that the overflow valve 9 of the signal control valve core 4 opens, the Ls port of the priority valve 2 overflows under high pressure through the overflow valve 9 in the signal control valve 4. At this time, the pump port maintains high pressure and flows to the oil tank through the EF port of the priority valve 2, but the pressure no longer continues to rise.

[0037] The signal control valve 4 is equipped with a throttling orifice D3, whose throttling area can control the filling flow rate. At the same time, the throttling orifices D1 and D2 will also affect the filling speed, but will also affect the turning flow rate.

[0038] This invention enables the working, steering, and braking systems to share the same pump source, and the systems do not interfere with each other, thus simultaneously meeting the performance requirements of the overall machine's steering, braking, and working hydraulic systems.

[0039] Example 2:

[0040] Based on the steering and braking system described in Embodiment 1, this embodiment provides a piece of engineering machinery equipped with a steering and braking system implemented in Embodiment 1.

[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 turning brake system characterized by, The system comprises: a gear pump (1), an oil outlet of which is connected with a P port of a priority valve (2); an EF port of the priority valve is combined with a working system; a CF port of the priority valve is connected with a P port of a steering gear (3) and a P port of a signal control valve (4) respectively; an Ls port of the steering gear (3) is connected with an Ls2 port of the signal control valve (4); an Ls port of the priority valve (2) is connected with an Ls1 port of the signal control valve (4); an A port of the signal control valve and a P port of a brake valve are connected with an accumulator (6) respectively; the steering gear (3) is used for controlling a steering cylinder to realize steering; the signal control valve (4) is used for controlling parking brake; the brake valve (5) is used for controlling service brake; the signal control valve (4) comprises a cut-off valve core (7), a charging valve core (8) and an overflow valve (9); an Ls1 port of the signal control valve (4) is connected with an oil inlet of the cut-off valve core (7); an Ls2 port of the signal control valve (4) is connected with a hydraulic control end of the cut-off valve core (7); a spring cavity of the cut-off valve core (7) is connected with a T port of the signal control valve (4); an oil outlet of the cut-off valve core (7) is connected with the T port of the signal control valve (4) through the overflow valve (9); a P port of the signal control valve (4) is connected with an oil inlet of the charging valve core (8), a hydraulic control end of the charging valve core (8), an A port of the signal control valve and an SW port of the signal control valve (4) respectively; the SW port of the signal control valve is connected with parking brake; an oil outlet of the charging valve core (8) is connected with the T port of the signal control valve (4) through the overflow valve (9); when the whole machine is being charged, steering is performed; at this time, the Ls2 port of the signal control valve (4) is raised in pressure to make the cut-off valve core (7) reverse to the left position; the accumulator (6) is cut off from the Ls1 port of the signal control valve (4), charging is stopped, steering action is normally performed, until the cut-off valve core (7) returns to the right position after the steering action is completed, the Ls1 port of the signal control valve (4) is communicated with the oil circuit of the charging valve core (8), at this time, it is judged whether the pressure of the accumulator (6) is lower than the minimum set value, if it is higher than the minimum set value, charging is not performed again, if it is still lower than the minimum set value, charging is started again.

2. The steering brake system according to claim 1, characterized in that, when the whole machine is not in action, the cut-off valve core (7) is in the right position, the Ls1 port of the signal control valve (4) is not communicated with the Ls2 port of the signal control valve (4), the Ls port of the priority valve (2) is communicated with the T port of the signal control valve (4) through the cut-off valve core (7) and the charging valve core (8) at this time, the priority valve is in the right position, the P port of the priority valve (2) is communicated with the EF port.

3. The turn brake system of claim 1, wherein, when the pressure of the accumulator (6) is lower than the minimum set value and steering is not performed, the Ls port of the priority valve (2) is communicated with the accumulator (6) through the cut-off valve core (7) and the charging valve core (8), the priority valve (2) reverses to the left position to make the pressure of the accumulator (6) rise to the maximum set value.

4. The turn brake system of claim 1, wherein, When the whole machine turns, the pressure of Ls2 port of signal control valve (4) is higher than the set value, Ls1 port of signal control valve (4) is communicated with Ls2 port of signal control valve (4); the pressure of CF port of priority valve (2) acts on the hydraulic control end of cut-off valve core (7) through steering gear (3), so that the cut-off valve core (7) is reversed.

5. The turn brake system of claim 1, wherein, LS port of the priority valve (2) is provided with throttling holes D1 and D2, and the reversing pressure p of the cut-off valve core (7) of the signal control valve (4) satisfies the following condition: （1） wherein is the area of the throttle hole is the area of the throttle hole is the area of the throttle hole is the area of the throttle hole is the area of the throttle hole 6. The turn brake system of claim 1, wherein, The overflow valve (9) is used for limiting the highest brake pressure, when the pressure of the accumulator (6) reaches the opening pressure of the overflow valve (9), the Ls port of the priority valve (2) to the Ls1 port of the signal control valve (4) and through the overflow valve (9) returns oil, at this time the priority valve (2) is in the right position, the flow of the gear pump (1) is overflowed to the EF port through the priority valve (2) high pressure.

7. The turn brake system of claim 1, wherein, The signal control valve (4) is provided with a throttling hole D3, and the throttling hole D3 is used for controlling the liquid filling flow of the accumulator (6).

8. A working machine, characterized in that The engineering machinery is provided with the steering brake system of any one of claims 1-7.

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