Priority valve group
By introducing a combination of high-pressure oil circuits, return oil circuits and other structures into the hydraulic system of engineering machinery, and combining switch valves and priority valves, the problems of complex priority valve structure and large pressure drop in the existing technology are solved, and a low-cost, low-pressure-drop priority actuator hydraulic oil supply is achieved.
Patent Information
- Application Number
- CN202422894892.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-09-09
- Estimated Expiration
- 2034-11-26
AI Technical Summary
In existing hydraulic systems of engineering machinery, priority valves have complex structures, high costs, and large pressure drops, making it difficult to effectively supply flow to the priority actuator.
A combined structure including a high-pressure oil circuit, a return oil circuit, a main oil circuit, a feedback oil circuit, a load-sensing oil circuit, a switch valve and a priority valve is adopted. Through the coordination of the switch valve and the priority valve, the flow supply of the priority actuator is realized and the system pressure drop is reduced.
A low-cost, easy-to-process priority actuator hydraulic oil supply is achieved, which reduces system pressure drop and energy consumption.
Smart Images
Figure CN223318158U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a priority valve group used in a hydraulic system of an engineering machinery, which can realize a priority flow supply function for a specific actuator. Background Art
[0002] Priority valves are often installed in the hydraulic systems of construction machinery to prioritize the flow requirements of specific actuators. For example, for construction machinery with steering functions, such as excavators, the hydraulic oil flow required for steering typically takes precedence over that required for other actions. When steering is performed while other actions are being performed simultaneously, and the system hydraulic oil flow cannot simultaneously meet the flow requirements of the steering actuator and other actuators, priority flow to the steering actuator must be ensured. This actuator, which requires priority flow, is referred to as a priority actuator. To this end, a priority valve is installed in the high-pressure oil circuit of the hydraulic system. This valve is typically a three-way valve with one inlet and two outlets, one of which supplies the priority actuator and the other supplies the other actuators. This priority valve has three valve positions. When the system flow is insufficient to simultaneously meet the flow requirements of the priority actuator and other actuators, the priority valve is in the first position, supplying all the system flow to the priority actuator. When the system flow can meet the flow requirements of both the priority actuator and other actuators, the priority valve is in the second position, distributing the system flow between the priority actuator and the other actuators. When there's no flow demand, the priority valve is in the third position, allowing all system flow to be supplied to other actuators. This three-position, three-way priority valve is a pressure compensator, resulting in a large pressure drop across the valve, leading to energy loss. It also has a complex structure, is difficult to manufacture, and is costly. Utility Model Content
[0003] An object of the present application is to provide an improved priority valve group, which can realize the priority supply of hydraulic oil to a specific hydraulic actuator through a simple structure and has a small pressure drop on both sides.
[0004] To this end, the present application provides, in one aspect, a priority valve assembly, comprising:
[0005] High-pressure oil circuit, return oil circuit, main oil circuit, feedback oil circuit, load-sensing oil circuit, as well as switch valves and priority valves;
[0006] The priority valve is arranged in the main oil circuit, dividing the main oil circuit into an upstream section and a downstream section. The upstream section of the main oil circuit is connected to the high-pressure oil circuit, and the downstream section extends to the oil supply port of the priority actuator. The priority valve is a hydraulic proportional valve, whose first control end is connected to the downstream section of the main oil circuit and the second control end is connected to the feedback oil circuit.
[0007] In which, the switch valve has a first valve position and a second valve position. In the first valve position, the oil inlet and the oil outlet of the switch valve are connected. In the second valve position, the oil inlet and the oil outlet of the switch valve are cut off. The oil inlet of the switch valve is connected to the upstream section of the main oil circuit, and the oil outlet is connected to the load-sensitive oil circuit. The first control end of the switch valve is connected to the high-pressure oil circuit, and the second control end is connected to the feedback oil circuit.
[0008] In one embodiment, one end of the feedback oil circuit is connected to the load feedback oil port of the priority actuator, and the other end is connected to the load sensitive oil circuit via a one-way valve.
[0009] In one embodiment, the second control end of the priority valve is connected to the feedback oil circuit via a control line provided with a first throttle.
[0010] In one embodiment, the feedback oil circuit is connected to the downstream section of the main oil circuit via a second throttle.
[0011] In one embodiment, a relief valve is provided between the control line of the second control end of the priority valve and the return oil circuit.
[0012] In one embodiment, the second control ends of the priority valve and the switch valve are respectively equipped with corresponding return springs.
[0013] In one embodiment, the switch valve and the priority valve have the following matching configuration:
[0014] The switch valve is in the first valve position, wherein the oil inlet of the switch valve is connected to the oil outlet; the priority valve is in a state of supplying flow to the oil supply port of the priority actuator, wherein all the hydraulic oil in the high-pressure oil circuit is supplied to the oil supply port of the priority actuator.
[0015] In one embodiment, the switch valve and the priority valve further have the following matching configuration:
[0016] The switch valve is in the second valve position, wherein the oil inlet and the oil outlet of the switch valve are cut off; the priority valve is in a state of supplying flow to the oil supply port of the priority actuator, wherein a portion of the hydraulic oil in the high-pressure oil circuit is supplied to the oil supply port of the priority actuator.
[0017] In one embodiment, the switch valve and the priority valve further have the following matching configuration:
[0018] The switch valve is in the second valve position, wherein the oil inlet and the oil outlet of the switch valve are cut off; the opening of the priority valve is zero, wherein the hydraulic oil in the high-pressure oil circuit is not supplied to the priority actuator oil supply port.
[0019] In one embodiment, the switch valve and the priority valve are integrated into a common single valve body, and the high-pressure oil circuit, the return oil circuit, the main oil circuit, the feedback oil circuit, and the load sensing oil circuit are formed in the single valve body.
[0020] The priority valve assembly of the present application realizes the priority supply of hydraulic oil to a specific hydraulic actuator with a simple structure, is low-cost and easy to manufacture. In addition, the pressure drop on both sides of the priority valve is low, reducing system energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The foregoing and other aspects of the present application will be more fully understood and appreciated through the following detailed description made with reference to the accompanying drawings, in which:
[0022] Figure 1 It is the hydraulic principle diagram of the priority valve group of this application;
[0023] Figure 2 It is a cross-sectional view of an exemplary structure of the priority valve group of the present application. DETAILED DESCRIPTION
[0024] This application generally relates to a priority valve assembly used in the hydraulic system of construction machinery, which is used to prioritize the supply of hydraulic oil to a specific hydraulic actuator. The construction machinery may be a steering-capable construction machinery, such as an excavator, where the flow demand of the steering actuator must be met before that of other actuators. Hereinafter, the actuator in the construction machinery whose hydraulic oil demand needs to be met first is referred to as a priority actuator.
[0025] The priority valve group of the present application can be integrated into a control module, and the control valve groups for other actuators are also integrated into corresponding control modules. These control modules can be connected in series by simple superposition, such as Figure 1 shown.
[0026] See Figure 1 The priority valve group V1 of the present application is used to supply hydraulic oil to the priority actuator of the construction machinery. The control valve group V2, which supplies hydraulic oil to another actuator, can be stacked with the priority valve group V1. The control valve groups (not shown) for supplying hydraulic oil to other actuators can be stacked in sequence behind the control valve group V2.
[0027] The priority valve group V1 includes a single valve body, in which at least the following oil circuits are formed: a high-pressure (oil supply) oil circuit L1, a return oil circuit L2, a main oil circuit L3, a feedback oil circuit L4, and a load-sensing oil circuit L5.
[0028] The following oil ports are formed on the valve body: P port (high-pressure inlet) for receiving hydraulic oil (system oil pressure) output by a hydraulic pump (not shown); P1 port (high-pressure outlet) for connecting to the high-pressure inlet of the control valve group V2; LS port (load-sensing oil port) for connecting to the variable mechanism of the main pump so as to adjust the displacement of the main pump based on load feedback; LS1 port (load-sensing inlet) for connecting to the load-sensing oil port of the control valve group V2; T port (return oil port) for connecting to an oil tank (not shown); T1 port and T2 port (both are return oil inlets) for connecting to the corresponding return oil ports of the control valve group V2; C port (priority actuator oil supply port) for connecting to the oil inlet of a priority actuator (such as a steering gear); CLS port (priority actuator load feedback oil port) for receiving feedback load from a priority actuator (such as a steering gear).
[0029] The priority valve group V1 includes the following hydraulic functional elements integrated into the single valve body: an on-off valve 1 , a one-way valve 2 , a priority valve 3 , a relief valve 4 , a first throttle 5 , and a second throttle 6 .
[0030] High-pressure oil circuit L1 is connected to port P at one end and to port P1 at the other. Return oil circuit L2 is connected to ports T1 and T2 at one end and to port T at the other. Main oil circuit L3 is connected to high-pressure oil circuit L1 at one end and to port C at the other. Feedback oil circuit L4 is connected to port CLS at one end and to load-sense oil circuit L5 via check valve 2. Check valve 2 is oriented to allow hydraulic oil to flow only from feedback oil circuit L4 to load-sense oil circuit L5, prohibiting reverse flow. Load-sense oil circuit L5 is connected to port LS at one end and to port LS1 at the other.
[0031] The priority valve 3 is arranged in the main oil circuit L3, and the priority valve 3 divides the main oil circuit L3 into an upstream section, that is, the section connected to the high-pressure oil circuit L1, and a downstream section, that is, the section connected to the C port.
[0032] The switch valve 1 is a two-position two-way valve having an oil inlet and an oil outlet, as well as a first valve position and a second valve position. The oil inlet of the switch valve 1 is connected to the upstream section of the main oil circuit L3, that is, connected to the high-pressure oil circuit L1. The oil outlet of the switch valve 1 is connected to the load-sensitive oil circuit L5. The first control end of the switch valve 1 is connected to the feedback oil circuit L4 and is provided with a return spring, and the second control end is connected to the high-pressure oil circuit L1. When the combined action of the oil pressure of the feedback oil circuit L4 and the return spring on the first control end of the switch valve 1 generates a force on the valve core that is greater than the force generated on the valve core by the oil pressure of the high-pressure oil circuit L1 on the second control end, the switch valve 1 is in the first valve position ( Figure 1(as shown in the valve position), at which point the oil inlet and outlet are connected, allowing hydraulic oil in main oil circuit L3 to flow through on-off valve 1 to load-sensing oil circuit L5. When the force exerted on the valve core by the oil pressure from high-pressure oil circuit L1 on the second control end of on-off valve 1 is greater than the force exerted on the valve core by the combined action of the oil pressure from feedback oil circuit L4 and the return spring on the first control end, on-off valve 1 is in the second valve position, blocking the oil inlet and outlet, and preventing hydraulic oil in main oil circuit L3 from flowing through on-off valve 1 to load-sensing oil circuit L5.
[0033] Priority valve 3 is a hydraulic proportional valve whose flow rate depends on the oil pressure at the control end. Priority valve 3 is oriented so that hydraulic oil in high-pressure oil circuit L1 can enter the main oil circuit L3, flow through priority valve 3, and be supplied to the priority actuator through port C. The first control end of priority valve 3 is connected to the downstream section of main oil circuit L3, while the second control end is equipped with a return spring and connected to feedback oil circuit L4 via a control line equipped with a first throttle 5. Feedback oil circuit L4 is also connected to the downstream section of main oil circuit L3 through a second throttle 6. The flow rate of priority valve 3 is determined by the combined effect of the oil pressure from the downstream section of main oil circuit L3 at the first control end, the oil pressure from the feedback oil circuit L4 at the second control end, and the action of the return spring.
[0034] The oil inlet of relief valve 4, located between the second control end of priority valve 3 and first throttle 5, is connected to the control line of the second control end of priority valve 3. The oil outlet is connected to return oil line L2. Relief valve 4 opens when the oil pressure in feedback oil line L4 exceeds its opening pressure, relieving pressure in feedback oil line L4.
[0035] The control valve assembly V2 includes a main control valve 7 and a compensation valve 8. The control valve assembly V2 receives high-pressure hydraulic oil from the high-pressure oil circuit L1 of the priority valve assembly V1 at port P1. This oil is supplied to port A1 via the main control valve 7 and then to the oil inlet of another actuator. Hydraulic oil from the oil outlet of this other actuator returns to the control valve assembly V2 via port B1, then flows through the main control valve 7 to port T1 of the priority valve assembly V1, and then returns to the tank via the return oil circuit L2 of the priority valve assembly V1. This application does not involve any improvements to the control valve assembly V2, and therefore will not be described in detail.
[0036] Back to the priority valve group V1, an exemplary structure thereof is Figure 2 The priority valve group V1 includes the aforementioned single valve body 10 , on which all functional components of the priority valve group V1 are integrated, and in which oil circuits and pipelines are formed, thereby being integrated into a control module.
[0037] Figure 2A cross section showing as many structural details as possible is selected to illustrate the internal structure of the priority valve group V1, which shows the on-off valve 1, the one-way valve 2, the priority valve 3, the overflow valve 4, the first throttle 5 and a part of the oil port.
[0038] from Figure 2 As can be seen in the figure, the valve cores of the switch valve 1, the priority valve 3 and the overflow valve 4 are arranged roughly in parallel in the corresponding valve chambers formed in the valve body 1, forming a compact structure.
[0039] The switch valve 1, one-way valve 2, priority valve 3, relief valve 4, first throttle 5, and second throttle 6 involved in this application all adopt existing structures without any structural improvements. Only corresponding valves are formed in the valve body 10 for them, and their components (especially the valve core) are installed in their respective valve chambers. Therefore, their structural details are not described here. The specific structures of these valves and throttles are well known to those skilled in the art.
[0040] Back to Figure 1 The priority valve group V1 of the present application replaces the compensation valve provided in the high-pressure oil circuit in the prior art through the combination of the switch valve 1 and the priority valve 3, and can also realize the function of prioritizing the supply of hydraulic oil to the priority actuator.
[0041] Specifically, the three working modes described below can be realized by combining the switching valve 1 and the priority valve 3 .
[0042] The first operating mode is the priority actuator mode. In this mode, the priority actuator has a flow demand (regardless of whether other actuators have flow demands), but the system flow rate is equal to or less than the priority actuator's flow demand. Switch valve 1, under the combined action of its return spring and the control oil pressure at both ends, is in the first position. Its oil inlet and outlet are connected, and the pressure at port P1 is equal to the pressure at port LS. The other control valve groups, through the position control of their compensator valves, shut off the oil supply from their control main valves to the corresponding actuators. System oil pressure from port P flows through main oil line L3, through priority valve 3, and to port C, where it is supplied to the priority actuator. This ensures that system oil pressure is supplied only to the priority actuator, meeting its flow demand. The flow rate to the priority actuator is controlled by the combined action of the return spring of priority valve 3 and the control oil pressure at both ends. There is no pressure compensator between ports P and C, so the system pressure drop is minimal.
[0043] The second operating mode is simultaneous operation. In this case, the priority actuator has a flow demand, and the other actuators also have flow demands. If the system flow exceeds the flow demand of the priority actuator, then on-off valve 1, under the combined action of its return spring and the control oil pressure at both ends, is in the second valve position, blocking the flow between its inlet and outlet. The control valve groups of the other actuators with flow demands control the position of their compensator valves, allowing their main control valves to supply oil to the corresponding actuators. System oil pressure from port P is simultaneously supplied to ports C and P1. Hydraulic oil from port C is supplied to the priority actuator, and hydraulic oil from port P1 is supplied to the other actuators with flow demands. The flow rate supplied to the priority actuator is controlled by the combined action of the return spring of priority valve 3 and the control oil pressure at both ends. The flow rate supplied to the other actuators with flow demands is controlled by the position of their control valve groups through the compensator valves. There are no pressure compensators between ports P and C, or between ports P and P1, resulting in minimal system pressure drop.
[0044] In the second operating mode, when the load on port C (priority actuator) is less than the load on port A1 in control valve group V2, the load pressure at port C, as reported by port CLS, is transmitted via feedback line L4 to the inlet of check valve 2. However, since the inlet pressure of check valve 2 is lower than the outlet pressure (i.e., the pressure in load-sensing line L5), it does not push open check valve 2 and transfer oil to load-sensing line L5, thus ensuring that port C is prioritized for oil supply. When the load on port C is greater than the load on port A1 in control valve group V2, the load pressure at port C, as reported by port CLS, is transmitted via feedback line L4 to the inlet of check valve 2. At this point, the inlet pressure of check valve 2 is higher than the outlet pressure (i.e., the pressure in load-sensing line L5), pushing open check valve 2 and transferring oil to load-sensing line L5. Furthermore, the pressure is transmitted via port LS1 to compensator 8 in control valve group V2, reducing the flow area of compensator 8 and thereby prioritizing the supply of hydraulic oil to port C, i.e., the priority actuator.
[0045] The third operating mode is the priority actuator no-demand mode. In this mode, the priority actuator has no flow demand, while the other actuators do. Consequently, the combined action of its return spring and the control oil pressure at both ends causes switch valve 1 to be in the second position, isolating the oil inlet and outlet. The return spring of priority valve 3 and the control oil pressure at both ends jointly control the opening of priority valve 3 to zero, effectively reducing the flow through priority valve 3 to zero. The entire system oil pressure from port P is supplied to port P1. There is no pressure compensator between ports P and P1, resulting in minimal system pressure drop.
[0046] The priority valve assembly of the present application achieves the priority supply of hydraulic oil to a specific hydraulic actuator with a simple structure, is low-cost, and easy to manufacture. Furthermore, compared with the existing technology using compensation valves, it has a smaller pressure drop and reduces system energy consumption.
[0047] Although the present application is described herein with reference to specific exemplary embodiments, the scope of the present application is not limited to the details shown, and various modifications may be made to these details without departing from the basic principles of the present application.
Claims
1. A priority valve group, characterized in that: include: High-pressure oil circuit (L1), return oil circuit (L2), main oil circuit (L3), feedback oil circuit (L4), load-sensing oil circuit (L5), as well as switch valve (1) and priority valve (3); The priority valve (3) is arranged in the main oil circuit (L3), dividing the main oil circuit (L3) into an upstream section and a downstream section, the upstream section of the main oil circuit (L3) is connected to the high-pressure oil circuit (L1), and the downstream section extends to the oil supply port (C) of the priority actuator, and the priority valve (3) is a hydraulic proportional valve, the first control end of which is connected to the downstream section of the main oil circuit (L3), and the second control end is connected to the feedback oil circuit (L4); The switch valve (1) has a first valve position and a second valve position. In the first valve position, the oil inlet and the oil outlet of the switch valve (1) are connected. In the second valve position, the oil inlet and the oil outlet of the switch valve (1) are cut off. The oil inlet of the switch valve (1) is connected to the upstream section of the main oil circuit (L3), and the oil outlet is connected to the load-sensitive oil circuit (L5). The first control end of the switch valve (1) is connected to the high-pressure oil circuit (L1), and the second control end is connected to the feedback oil circuit (L4).
2. The priority valve assembly according to claim 1, characterized in that: One end of the feedback oil circuit (L4) is connected to the load feedback oil port (CLS) of the priority actuator, and the other end is connected to the load sensitive oil circuit (L5) via a one-way valve (2).
3. The priority valve assembly according to claim 1, characterized in that: The second control end of the priority valve (3) is connected to the feedback oil circuit (L4) via a control pipeline provided with a first throttle (5).
4. The priority valve assembly according to claim 3, characterized in that: The feedback oil circuit (L4) is connected to the downstream section of the main oil circuit (L3) via a second throttle (6).
5. The priority valve assembly according to claim 3, characterized in that: An overflow valve (4) is provided between the control pipeline of the second control end of the priority valve (3) and the return oil circuit (L2).
6. The priority valve assembly according to claim 1, characterized in that: The second control ends of the priority valve (3) and the switch valve (1) are respectively equipped with corresponding return springs.
7. The priority valve assembly according to any one of claims 1 to 6, characterized in that: The switch valve (1) and the priority valve (3) have the following matching forms: The switch valve (1) is in a first valve position, wherein the oil inlet of the switch valve (1) is connected to the oil outlet; the priority valve (3) is in a state of supplying flow to the priority actuator oil supply port (C), wherein all the hydraulic oil in the high-pressure oil circuit (L1) is supplied to the priority actuator oil supply port (C).
8. The priority valve assembly according to claim 7, characterized in that: The switch valve (1) and the priority valve (3) also have the following matching forms: The switch valve (1) is in the second valve position, wherein the oil inlet and the oil outlet of the switch valve (1) are cut off; the priority valve (3) is in a state of supplying flow to the priority actuator oil supply port, wherein a portion of the hydraulic oil in the high-pressure oil circuit (L1) is supplied to the priority actuator oil supply port (C).
9. The priority valve assembly according to claim 8, characterized in that: The switch valve (1) and the priority valve (3) also have the following matching forms: The switch valve (1) is in the second valve position, wherein the oil inlet and the oil outlet of the switch valve (1) are cut off; the opening of the priority valve (3) is zero, wherein the hydraulic oil in the high-pressure oil circuit (L1) is not supplied to the priority actuator oil supply port (C).
10. The priority valve assembly according to any one of claims 1 to 6, characterized in that: The switch valve (1) and the priority valve (3) are integrated into a common single valve body (10), and the high-pressure oil circuit (L1), the return oil circuit (L2), the main oil circuit (L3), the feedback oil circuit (L4), and the load-sensing oil circuit (L5) are formed in the single valve body (10).