Hydraulic brake prefill valve group, hydraulic system and forklift

Abstract

The utility model discloses a hydraulic brake prefill valve bank, hydraulic system and forklift, hydraulic brake prefill valve bank includes a plurality of control valves, the plurality of control valves include pressure compensation valve, unloading valve and logic valve, the oil inlet of pressure compensation valve is used for inputting hydraulic oil, and the oil outlet of pressure compensation valve is used for inputting the unloading valve. One working oil port of the pressure compensation valve is communicated with an oil inlet of the unloading valve and an oil inlet of the logic valve, and a load port of the unloading valve is used for being communicated with an oil port of the energy accumulator; a pilot control port of the unloading valve communicates with a control oil port of the logic valve, and an oil return port of the unloading valve and an oil return port of the logic valve are used for communicating with an oil tank. A brand new liquid filling mode is provided for the energy accumulator, liquid filling of the energy accumulator can be preferentially met, the energy accumulator does not need to be filled with liquid through an integrated priority valve, and therefore the problem that the performance of a brake system is reduced due to the fact that oil of the energy accumulator is insufficient is solved or effectively improved.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic control technology, and in particular to a hydraulic brake filling valve assembly, a hydraulic system, and a forklift. Background Technology

[0002] In forklifts, accumulators are typically used in the braking system to ensure that the braking system continues to function properly even when the power source is not operational, enabling multiple emergency braking maneuvers. Currently, forklift accumulators generally employ an integrated priority valve to control fluid filling. This integrated priority valve is a multi-functional hydraulic control element that integrates a filling valve, a pressure reducing valve, and a solenoid valve. It is used for releasing the forklift's parking brake and filling the accumulator with fluid for the braking system. Furthermore, this integrated priority valve also controls the forklift's steering function and, through an integrated sequence valve, guides excess fluid back to the main hydraulic circuit to improve system efficiency.

[0003] However, existing integrated priority valve designs have a problem: they prioritize steering demand in fluid distribution, which may result in the accumulator not receiving enough fluid for charging in a timely manner. This can affect the forklift's braking force, as insufficient accumulator fluid reduces the performance of the braking system. Utility Model Content

[0004] This utility model addresses the technical problems existing in the prior art by providing a hydraulic brake filling valve assembly, a hydraulic system, and a forklift. It provides a filling method for the accumulator, which can prioritize filling the accumulator and has an unloading function.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a hydraulic brake filling valve assembly, including multiple control valves, the multiple control valves including a pressure compensation valve, an unloading valve and a logic valve, the oil inlet of the pressure compensation valve is used to input hydraulic oil, one of the working oil ports of the pressure compensation valve is connected to the oil inlet of the unloading valve and the oil inlet of the logic valve, the load port of the unloading valve is used to connect to the oil port of the accumulator; the pilot control port of the unloading valve is connected to the control oil port of the logic valve, and the return oil port of the unloading valve and the return oil port of the logic valve are used to connect to the oil tank.

[0006] In a preferred embodiment, the plurality of control valves further includes a safety valve, wherein the oil inlet of the unloading valve is connected to the oil inlet of the safety valve, and the oil return port of the safety valve is used to connect to the oil tank.

[0007] In a preferred embodiment, a damper is further included, which is connected in a hydraulic line between one of the working ports of the pressure compensation valve and the inlet of the unloading valve and the inlet of the logic valve; the inlet of the unloading valve is connected to the load feedback port of the pressure compensation valve.

[0008] In a preferred embodiment, the plurality of control valves further include a solenoid valve and a pressure reducing valve. The oil inlet of the solenoid valve is connected to the oil inlet of the accumulator. The load port of the solenoid valve is connected to the oil inlet of the pressure reducing valve. The oil outlet of the pressure reducing valve is connected to the oil inlet of the gearbox and is connected to the oil inlet of the pressure reducing valve through a check valve. The pilot drain port of the pressure reducing valve and the return port of the solenoid valve are connected to the oil tank.

[0009] In a preferred embodiment, a valve body is also included, which integrates the plurality of control valves together.

[0010] In a preferred embodiment, the valve body is provided with an oil port P connected to the oil inlet of the pressure compensation valve, an oil port N connected to the oil return port of the unloading valve and the oil return port of the logic valve, an oil port A connected to the load port of the unloading valve, and an oil port EF connected to another working oil port of the pressure compensation valve.

[0011] In a preferred embodiment, the system further includes a first pressure sensor for detecting the oil pressure of the accumulator; and a second pressure sensor for detecting the oil pressure of the transmission.

[0012] In a preferred embodiment, the unloading valve is a pressure-adjustable structure.

[0013] This utility model also provides a hydraulic system, including a hydraulic pump, an oil tank and an accumulator, and also includes a hydraulic brake charging valve group as described above. The oil inlet of the pressure compensation valve is connected to the working oil port of the hydraulic pump, the load port of the unloading valve is connected to the oil port of the accumulator, and the oil return port of the unloading valve and the oil return port of the logic valve are connected to the oil tank.

[0014] This utility model also provides a forklift, including the hydraulic system described above.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The multiple control valves of this utility model, including the pressure compensation valve, unloading valve, and logic valve, provide a novel filling method for the accumulator. This method prioritizes accumulator filling, eliminating the need for an integrated priority valve and thus solving or effectively improving the performance degradation of the braking system caused by insufficient accumulator fluid. Specifically, the unloading valve and logic valve of this utility model provide independent unloading functionality, allowing excess fluid to be directly returned to the oil tank. This ensures stable accumulator filling while simultaneously reducing motor speed upon completion of filling, thereby contributing to energy savings.

[0017] 2. This utility model also includes a safety valve, which can guarantee the upper limit of oil circuit pressure and solve the shortcomings of the prior art that requires an external safety unloading circuit.

[0018] 3. The damper can be set to adjust the flow rate, and the damper combined with the pressure compensation valve can achieve a constant flow rate, which is not affected by the load of the accumulator.

[0019] 4. This new type also includes a solenoid valve and a pressure reducing valve, which can provide depressurized hydraulic pressure for the forklift to release the parking position, thereby realizing the release action.

[0020] 5. This utility model also includes a valve body, which integrates the multiple control valves together, making the overall structure compact and optimizing the system layout. This not only saves space and cost, but also improves the reliability, performance and maintainability of the system.

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments; however, the hydraulic brake filling valve assembly, hydraulic system and forklift of the present invention are not limited to the embodiments. Attached Figure Description

[0022] Figure 1 This is a hydraulic schematic diagram of the hydraulic brake filling valve assembly of this utility model;

[0023] Figure 2 This is a three-dimensional structural schematic diagram of the hydraulic brake filling valve assembly of this utility model;

[0024] In the diagram, 1 is a pressure compensation valve; 2 is an unloading valve; 3 is a logic valve; 4 is a safety valve; 5 is a damper; 6 is a solenoid valve; 7 is a pressure reducing valve; 8 is a check valve; 9 is a first pressure sensor; 10 is a second pressure sensor; and 20 is a valve body. Detailed Implementation

[0025] In this invention, the terms "first," "second," etc., are used only to distinguish similar objects, not to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0026] Please see Figures 1-2 As shown, this utility model discloses a hydraulic brake filling valve assembly, which includes multiple control valves, including a pressure compensation valve 1. 、 Unloading valve 2 and logic valve 3 ，The inlet ③ of the pressure compensation valve 1 is used to input hydraulic oil. One of the working ports ④ of the pressure compensation valve 1 is connected to the inlet ① of the unloading valve 2 and the inlet ① of the logic valve 3. The load port ② of the unloading valve 2 is used to connect to the accumulator's oil port. The pilot control port ③ of the unloading valve 2 is connected to the control port ③ of the logic valve 3. The return port ④ of the unloading valve 2 and the return port ② of the logic valve 3 are used to connect to the oil tank. Therefore, this invention can charge the accumulator separately and can prioritize the charging of the accumulator, so that the accumulator does not need to use the integrated priority valve of the prior art for charging.

[0027] The aforementioned control valves also include a safety valve 4. The oil inlet ① of the unloading valve 2 is connected to the oil inlet ① of the safety valve 4, and the oil return port ② of the safety valve 4 is used to connect to the oil tank. The oil inlet ① of the unloading valve 2 is connected to the load feedback port ① of the pressure compensation valve 1. Therefore, this invention can guarantee the upper limit of the oil circuit pressure and ensure that the pressure for charging the accumulator is limited by the safety valve 4 and does not exceed the set threshold.

[0028] This invention also includes a damper 5, which is connected in the hydraulic circuit between one of the working ports of the pressure compensation valve 1 and the inlet ① of the unloading valve 2 and the inlet ① of the logic valve 3. This allows the hydraulic oil output from one of the working ports ④ of the pressure compensation valve 1 to first pass through the damper 5 to regulate its flow before flowing to the unloading valve 2 and / or the logic valve 3. The inlet ① of the unloading valve 2 is connected to the load feedback port ① of the pressure compensation valve 1, ensuring a constant pressure difference between the inlet and outlet of the damper 5, thus achieving the pressure compensation function. Together, these factors ensure priority charging of the accumulator and a constant charging time.

[0029] The multiple control valves also include a solenoid valve 6 and a pressure reducing valve 7. The oil inlet ① of the solenoid valve 6 is connected to the oil inlet of the accumulator. The load port ② of the solenoid valve 6 is connected to the oil inlet ② of the pressure reducing valve 7. The oil outlet ① of the pressure reducing valve 7 is connected to the oil inlet of the gearbox and is connected to the oil inlet ② of the pressure reducing valve 7 through a one-way valve 8. Specifically, the oil inlet ① of the one-way valve 8 is connected to the oil outlet ① of the pressure reducing valve 7, and the oil outlet ② of the one-way valve 8 is connected to the oil inlet ② of the pressure reducing valve 7. The pilot drain port ③ of the pressure reducing valve 7 and the return port ③ of the solenoid valve 6 are connected to the oil tank.

[0030] This utility model also includes a valve body 20, which integrates multiple control valves, making the overall structure compact and optimizing the system layout. Therefore, this utility model constitutes an integrated valve. The valve body 20 is provided with an oil port P connected to the oil inlet ③ of the pressure compensation valve 1, an oil port N connected to the oil return port ④ of the unloading valve 2 and the oil return port ② of the logic valve 3, an oil port A connected to the load port ② of the unloading valve 2 and the oil inlet ① of the solenoid valve 6, an oil port EF connected to the other working oil port ② of the pressure compensation valve 1, an oil port T2 connected to the pilot drain port ③ of the pressure reducing valve 7 and the oil return port ③ of the solenoid valve 6, and an oil port B connected to the oil outlet ① of the pressure reducing valve 7. This facilitates the connection of the entire filling valve assembly with external hydraulic components.

[0031] This invention also includes a first pressure sensor 9 and a second pressure sensor 10. The first pressure sensor 9 is used to detect the oil pressure of the accumulator, and the second pressure sensor 10 is used to detect the oil pressure of the transmission. Specifically, the first pressure sensor 9 is connected to the hydraulic line between the load port ② of the unloading valve 2 and the oil port of the accumulator, and the second pressure sensor 10 is connected to the hydraulic line between the oil outlet ① of the pressure reducing valve 7 and the oil inlet of the transmission.

[0032] As a preferred embodiment, the unloading valve 2 is a pressure-adjustable structure, which facilitates precise pressure adjustment to protect the system, save energy, and ensure stable operation, making it suitable for various working conditions.

[0033] This utility model discloses a hydraulic brake filling valve assembly, which can be applied to the hydraulic system of a forklift. The hydraulic system includes a hydraulic pump, an oil tank, an accumulator, and a gearbox. In application, the oil inlet ③ of the pressure compensation valve 1 is connected to the working oil port of the hydraulic pump, the load port ② of the unloading valve 2 is connected to the oil port of the accumulator, the return oil port ④ of the unloading valve 2, the return oil port ② of the logic valve 3, the return oil port ② of the safety valve 4, the pilot drain port ③ of the pressure reducing valve 7, and the return oil port ③ of the solenoid valve 6 are connected to the oil tank, the oil outlet ① of the pressure reducing valve 7 is connected to the oil inlet of the gearbox, that is, the oil port P on the valve body 20 is connected to the working oil port of the hydraulic pump, the oil ports N and T2 on the valve body 20 are connected to the oil tank, the oil port A on the valve body 20 is connected to the oil port of the accumulator, and the oil port B on the valve body 20 is connected to the oil inlet of the gearbox.

[0034] During operation, hydraulic oil from the hydraulic pump is output from one of the working ports ④ of the pressure compensation valve 1, and after being throttled by the damper 5, it flows to the inlet port ① of the unloading valve 2. Then, it is output from the load port ② of the unloading valve 2 and flows to the accumulator to charge it. While the accumulator is not fully charged, the unloading valve 2 is in the neutral position. At this time, the pilot control port ③ and the return port ④ of the unloading valve 2 are not connected. Therefore, the control port ③ of the logic valve 3 can maintain pressure, keeping the logic valve 3 in the neutral position and preventing the inlet port ① and return port ② of the logic valve 3 from connecting, thus ensuring the accumulator's charging and pressure-building process. When the accumulator is fully charged, the pressure at the load port ② of the unloading valve 2 is greater than the set pressure of the unloading valve 2. Therefore, the unloading valve 2 switches, causing the pilot control port ③ and the return port ④ of the unloading valve 2 to connect, thereby releasing the pressure at the control port ③ of the logic valve 3. Under the pressure difference of the internal control oil pressure, the logic valve 3 switches, connecting the inlet port ① and the return port ② of the logic valve 3, thereby realizing the system pressure relief action after the accumulator is fully charged.

[0035] When the accumulator pressure is insufficient, unloading valve 2 and logic valve 3 return to the neutral position respectively, and the accumulator is refilled with liquid, thus repeating the cycle.

[0036] The accumulator is connected to the oil inlet ① of the solenoid valve 6, and the load port ② of the solenoid valve 6 is connected to the oil inlet ② of the pressure reducing valve 7. The solenoid valve 6 receives an electrical signal reversal, which can provide the pressure-reduced hydraulic pressure to release the forklift from parking, thereby realizing the parking release action.

[0037] Therefore, by setting a pressure compensation valve 1, this utility model can prioritize meeting the accumulator filling requirements, i.e., the flow rate demand at port A. The flow rate can be adjusted by installing dampers 5 of different orifice diameters through the damping holes inside the valve body 20. Most importantly, this flow rate is constant and unaffected by the accumulator load, thus ensuring a constant filling time and good filling performance during normal operation. Simultaneously, the remaining flow rate is supplied to port EF, which can be connected to an external multi-way valve.

[0038] The reset pressure of unloading valve 2 is 80% of its set pressure. Therefore, when the accumulator pressure reaches the set pressure of unloading valve 2, unloading valve 2 switches, logic valve 3 switches, and oil returns to the oil tank. When the accumulator pressure is lower than 80% of the set pressure of unloading valve 2, unloading valve 2 resets, logic valve 3 resets, and the accumulator is recharged. This control method ensures that the accumulator charging time is within 1.5 seconds, providing a fast response time, and can reduce the motor speed after charging is completed, thus contributing to energy saving. This invention also includes a safety valve 4 for regulating oil circuit pressure to ensure the safety of the actuator.

[0039] The present invention provides a hydraulic system comprising a hydraulic pump, an oil tank, and an accumulator, and further comprising a hydraulic brake charging valve assembly as described above. The oil inlet ③ of the pressure compensation valve 1 is connected to the working oil port of the hydraulic pump, the load port ② of the unloading valve 2 is connected to the oil port of the accumulator, and the oil return port ④ of the unloading valve 2 and the oil return port ② of the logic valve 3 are connected to the oil tank.

[0040] This utility model also includes a gearbox, and the oil outlet ① of the pressure reducing valve 7 is connected to the oil inlet of the gearbox.

[0041] For details on the structure and working principle of the hydraulic brake filling valve assembly, please refer to the previous description; it will not be repeated here.

[0042] The present invention provides a forklift, including the hydraulic system described above.

[0043] This utility model discloses a hydraulic brake filling valve assembly, a hydraulic system, and a forklift. The parts not described herein are the same as or can be implemented using existing technologies.

[0044] The above embodiments are only used to further illustrate a hydraulic brake filling valve assembly, hydraulic system, and forklift of the present invention. However, the present invention is not limited to the embodiments. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A hydraulic brake fluid charging valve group comprising a plurality of control valves, characterized by: The multiple control valves include a pressure compensation valve, an unloading valve and a logic valve, an oil inlet of the pressure compensation valve is used for inputting hydraulic oil, one of working oil outlets of the pressure compensation valve is connected with an oil inlet of the unloading valve and an oil inlet of the logic valve, a load port of the unloading valve is used for connecting an oil port of an accumulator; a pilot control port of the unloading valve is connected with a control oil port of the logic valve, and a return oil port of the unloading valve and a return oil port of the logic valve are used for connecting an oil tank.

2. The hydraulic brake fluid charging valve group according to claim 1, characterized in that: The multiple control valves further include a safety valve, the oil inlet of the unloading valve is connected with an oil inlet of the safety valve, and a return oil port of the safety valve is used for connecting the oil tank.

3. The hydraulic brake fluid charging valve group of claim 1, wherein: A damper is further included, which is connected to a hydraulic oil circuit between one of the working oil outlets of the pressure compensation valve and the oil inlets of the unloading valve and the logic valve; and the oil inlet of the unloading valve is connected with a load feedback port of the pressure compensation valve.

4. The hydraulic brake fluid charging valve group of claim 1, wherein: The multiple control valves further include a solenoid valve and a pressure reduction valve, an oil inlet of the solenoid valve is used for connecting the oil inlet of the accumulator, a load port of the solenoid valve is connected with an oil inlet of the pressure reduction valve, an oil outlet of the pressure reduction valve is used for connecting an oil inlet of a gearbox, the oil inlet of the pressure reduction valve is connected with a one-way valve, a pilot oil discharge port of the pressure reduction valve and a return oil port of the solenoid valve are used for connecting the oil tank.

5. The hydraulic brake fluid charging valve group according to any one of claims 1-4, characterized in that: A valve body is further included, which integrates the multiple control valves.

6. The hydraulic brake fluid charging valve group of claim 5, wherein: The valve body is provided with an oil port P connected with the oil inlet of the pressure compensation valve, an oil port N connected with the return oil ports of the unloading valve and the logic valve, an oil port A connected with the load port of the unloading valve, and an oil port EF connected with another working oil outlet of the pressure compensation valve.

7. The hydraulic brake fluid charging valve group of claim 4, wherein: A first pressure sensor is further included, which is used for detecting an oil pressure of the accumulator; and a second pressure sensor is further included, which is used for detecting an oil pressure of the gearbox.

8. The hydraulic brake fluid charging valve group of claim 1, wherein: The unloading valve is of an adjustable pressure structure.

9. A hydraulic system comprising a hydraulic pump, a tank and an accumulator, characterized in that: The hydraulic brake fluid charging valve group according to any one of claims 1-8 is further included, the oil inlet of the pressure compensation valve is connected with a working oil outlet of a hydraulic pump, the load port of the unloading valve is connected with an oil port of the accumulator, and the return oil ports of the unloading valve and the logic valve are connected with the oil tank.

10. A fork truck characterized by: The hydraulic system according to claim 9 is included.

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