Hydraulic system
By using pressure sensing valves in the hydraulic system to control the on and off of the pilot oil circuit, the structural complexity and heating problems caused by multiple safety valves in the prior art are solved, and simpler and more reliable oil pressure management and system stability are achieved.
Patent Information
- Application Number
- CN202420645952.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-29
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-03-29
AI Technical Summary
Due to the use of multiple safety valves in existing hydraulic systems, there are many parts, complex structures, high failure rate, high cost, and high pressure and large flow rate overflow, which will cause large-scale heating of the hydraulic system.
The pressure sensing valve is used to control the oil pressure on the pilot oil circuit, and the pilot oil circuit is cut off by sensing the pressure in the main oil circuit, avoiding excessive oil pressure, simplifying the structure and reducing the risk of heating.
Through the use of pressure sensing valves, the number of main safety valves and port safety valves is reduced, the structure is simplified, the failure rate and cost are reduced, and the overheating problem of hydraulic system is avoided, and effective oil pressure management is achieved.
Smart Images
Figure CN222229007U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of hydraulic pressure, in particular to a hydraulic system. Background Art
[0002] In the prior art, a main safety valve is provided at the oil inlet of the electric main control valve to limit the maximum pressure of the oil inlet; the working oil port of the electric main control valve is connected to the actuator, and the actuator limits the maximum pressure of the working port and protects the actuator through the port safety valve.
[0003] like Figure 1 As shown, the pressure oil pumped out by the hydraulic pump 1' is supplied to the electronically controlled main control valve 2', and the two working oil ports of the electronically controlled main control valve 2' are connected to the A' port and the B' port of the actuator 3'. In order to ensure the safety of the hydraulic system, the main oil circuit between the hydraulic pump 1' and the oil inlet of the electronically controlled main control valve 2' is connected with a main oil leakage circuit 4', and a main safety valve 41' is arranged on the main oil leakage circuit 4', which can control the oil pressure of the main oil circuit to prevent the oil pressure in the main oil circuit from being too high; in order to ensure that the oil pressure at the two ports is not too high, the A' port is connected with the A' side oil leakage circuit 5', and the A' side oil leakage circuit 5' is provided with an A' side port safety valve 51', and the B' port is connected with the B' side oil leakage circuit 6', and the B' side oil leakage circuit 6' is provided with a B' side port safety valve 61'.
[0004] The above-mentioned setting limits the oil pressure at the oil inlet and working port of the electric control main control valve through multiple safety valves, which can play a protective role. However, it also causes the electric control main control valve to have many parts, complex structure, high failure rate and high cost. In addition, when the main safety valve and the port safety valve overflow at high pressure and large flow, it will cause a lot of heat in the hydraulic system. Utility Model Content
[0005] In order to solve the technical problem that multiple safety valves are used in the prior art to limit the oil pressure, resulting in many parts and a complex structure, the utility model provides a hydraulic system to solve the above technical problem.
[0006] In order to solve the above technical problems, the utility model provides a hydraulic system, comprising:
[0007] A main oil circuit, wherein a hydraulic pump, a main control valve and an actuator are arranged on the main oil circuit, and the oil pumped out by the hydraulic pump supplies oil to the actuator under the control of the main control valve;
[0008] A pilot oil circuit, wherein the pilot oil circuit supplies pilot oil to the main control valve. A pressure sensing valve is provided on the pilot oil circuit, and the pressure sensing valve senses the oil pressure of the main oil circuit. The pressure sensing valve controls the on-off of the pilot oil circuit. When the oil pressure of the main oil circuit exceeds a preset value, the pressure sensing valve cuts off the pilot oil circuit.
[0009] According to an embodiment of the utility model, when the main control valve is in a neutral position, the oil pumped out by the hydraulic pump is drained through the main control valve.
[0010] According to an embodiment of the utility model, the valve core of the pressure sensing valve slides under the oil pressure of the main oil circuit.
[0011] According to an embodiment of the utility model, an elastic member is provided at one end of the valve core of the pressure sensing valve, and a pilot chamber is formed at the other end of the valve core of the pressure sensing valve, and the pilot chamber takes pressure from the main oil circuit.
[0012] According to an embodiment of the utility model, the pilot chamber of the pressure sensing valve takes pressure from the higher port oil pressure of the two ports of the actuator;
[0013] Alternatively, the pilot chamber of the pressure sensing valve takes pressure from the oil pressure in the oil circuit between the hydraulic pump and the main control valve.
[0014] According to one embodiment of the utility model, a sequence valve is also arranged on the oil circuit between the hydraulic pump and the main control valve, and the pilot chamber of the pressure sensing valve takes pressure from the oil pressure at the pump outlet of the hydraulic pump; or, the pilot chamber of the pressure sensing valve takes pressure from the oil pressure between the sequence valve and the main control valve.
[0015] According to one embodiment of the utility model, one end of the pilot oil circuit is connected to the pump outlet of the hydraulic pump, and the other end of the pilot oil circuit is connected to the first pilot chamber and the second pilot chamber at both ends of the main control valve. A pressure reducing valve is also provided on the pilot oil circuit, and the outlet of the pressure reducing valve is connected to the inlet of the pressure sensing valve.
[0016] According to an embodiment of the utility model, a pressure reducing valve is further provided on the pilot oil circuit, and the pilot oil enters the pressure sensing valve after passing through the pressure reducing valve.
[0017] According to an embodiment of the present utility model, reset components are respectively provided at both ends of the main control valve.
[0018] According to an embodiment of the utility model, it further includes a solenoid valve, wherein there are two solenoid valves, which are respectively arranged for the first pilot chamber and the second pilot chamber, and the solenoid valves control the oil inlet and outlet of the corresponding pilot chamber.
[0019] Based on the above technical solution, the technical effects that can be achieved by the utility model are:
[0020] 1. The hydraulic system of the utility model controls the on-off of the pilot oil circuit by setting a pressure sensing valve on the pilot oil circuit and sensing the pressure of the main oil circuit through the pressure sensing valve. When the pressure of the main oil circuit exceeds the preset value, the pressure sensing valve can cut off the pilot oil circuit and stop supplying pilot oil to the main control valve, and the main control valve stops working, which can prevent the oil pressure of the main oil circuit from being too high. By setting the pressure sensing valve, the main safety valve and two port safety valves in the prior art can be omitted, reducing parts and simplifying the structure;
[0021] 2. In the hydraulic system of the utility model, when the main control valve is set in the middle position, the oil pumped out by the hydraulic pump can be directly drained through the main control valve, which can achieve low-pressure oil drainage, prevent the main oil circuit oil pressure from being too high, and avoid the problem of large-scale heating of the hydraulic system; when the pressure sensing valve senses that the oil pressure of the main oil circuit exceeds the preset value, the pilot oil circuit can be cut off, and the main control valve returns to the middle position under the action of the reset parts on both sides, and the oil pumped out by the hydraulic pump is directly drained through the main control valve at low pressure, reducing the oil pressure of the main oil circuit without causing heating problems;
[0022] 3. In the hydraulic system of the utility model, the pilot chamber of the pressure sensing valve takes pressure from the main oil circuit. Specifically, the pilot chamber of the pressure sensing valve can take pressure from the higher oil pressure of the two ports of the actuator. When the higher oil pressure of the two ports exceeds the preset pressure value of the pressure sensing valve, the pressure sensing valve cuts off the pilot oil circuit, stops supplying pilot oil to the main control valve, the main control valve is in the middle position, and the hydraulic pump discharges oil through the main control valve at low pressure. The pilot chamber of the pressure sensing valve can also take pressure from the oil pressure on the oil circuit between the hydraulic pump and the main control valve. When the oil pressure between the hydraulic pump and the main control valve exceeds the preset pressure value of the pressure sensing valve, the pressure sensing valve cuts off the pilot oil circuit, stops supplying pilot oil to the main control valve, the main control valve is in the middle position, and the hydraulic pump discharges oil through the main control valve at low pressure. The pressure sensing valve can take pressure from multiple locations in the main oil circuit to control the oil pressure of the main oil circuit.
[0023] 4. In the hydraulic system of the utility model, a sequence valve is provided on the oil circuit between the hydraulic pump and the main control valve. The sequence valve can be used to ensure the minimum pressure of the main oil circuit, which can meet the minimum pilot pressure required for the switching of the main control valve. The pressure sensing valve can take the oil pressure at the outlet of the hydraulic pump, and can also take the oil pressure between the sequence valve and the main control valve, both of which can sense the oil pressure of the main oil circuit and then control the on-off of the pilot oil circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 It is a schematic diagram of a hydraulic system in which an electric-controlled main control valve in the prior art is located;
[0025] Figure 2 This is a schematic diagram of a hydraulic system according to Embodiment 1 of the present utility model;
[0026] Figure 3 This is a partial enlarged view of the main control valve;
[0027] Figure 4 is a schematic diagram of a hydraulic system of Embodiment 2;
[0028] Figure 5 It is a schematic diagram of the hydraulic system of embodiment 3;
[0029] In the figure: 1-hydraulic pump; 2-main control valve; 3-actuator; 4-sequence valve; 5-oil tank; 6-pressure sensing valve; 7-solenoid valve; 8-pressure reducing valve; 9-shuttle valve; 10-main oil circuit; 20-pilot oil circuit; 1'-hydraulic pump; 2'-electrically controlled main control valve; 3'-actuator; 4'-main oil leakage circuit; 41'-main safety valve; 5'-A' side oil leakage circuit; 51'-A' side port safety valve; 6'-B' side oil leakage circuit; 61'-B' side port safety valve. DETAILED DESCRIPTION
[0030] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the utility model and its application or use. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.
[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.
[0032] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values of the parts and steps set forth in these embodiments do not limit the scope of the utility model. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.
[0033] In the description of the present utility model, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present utility model; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.
[0034] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.
[0035] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the utility model.
[0036] Embodiment 1
[0037] like Figure 2-3 As shown, this embodiment provides a hydraulic system, including a main oil circuit 10 and a pilot oil circuit 20. A hydraulic pump 1, a main control valve 2 and an actuator 3 are arranged on the main oil circuit 10. The oil pressure pumped by the hydraulic pump 1 supplies oil to the actuator 3 under the control of the main control valve 2; the pilot oil circuit 20 provides pilot oil to the main control valve 2.
[0038] The main oil circuit 10 is used to supply oil to the actuator 3 to control the movement of the actuator 3. A hydraulic pump 1 and a main control valve 2 are provided on the main oil circuit 10. The oil pumped by the hydraulic pump 1 is supplied to the main control valve 2. The main control valve 2 is connected to the actuator 3. The main control valve 2 controls the oil inlet and return of the actuator 3.
[0039] As the preferred technical solution of this embodiment, the main control valve 2 has a middle position and two working positions. When the main control valve 2 is in the middle position, the oil pumped out by the hydraulic pump 1 returns through the main control valve 2; when the main control valve 2 is in the two working positions, the oil pumped out by the hydraulic pump 1 enters one port of the actuator 3 under the control of the main control valve 2, and the other port of the actuator 3 returns through the main control valve 2.
[0040] As the preferred technical solution of this embodiment, the main control valve 2 is set as a three-position six-way valve, and the main control valve 2 includes p1 oil port, p2 oil port, t1 oil port, t2 oil port, a oil port and b oil port. The p1 oil port and the p2 oil port are both connected to the pump outlet of the hydraulic pump 1, and the t1 oil port and the t2 oil port are both connected to the oil tank 5; the a oil port is connected to the A port of the actuator 3, and the b oil port is connected to the B port of the actuator 3. When the main control valve 2 is in the middle position, the p2 oil port is connected to the t2 oil port, and the other oil ports are not connected, and the oil pumped out by the hydraulic pump 1 can return to the oil tank 5 through the main control valve 2; when the main control valve 2 is in the first working position, the p2 oil port is disconnected from the t2 oil port, the p1 oil port is connected to the a oil port, and the t1 oil port is connected to the b oil port, so that the oil pumped out by the hydraulic pump 1 can be supplied to the A port of the actuator 3, and the B port of the actuator 3 can return oil; when the main control valve 2 is in the second working position, the p2 oil port is disconnected from the t2 oil port, the p1 oil port is connected to the b oil port, and the t1 oil port is connected to the a oil port, so that the oil pumped out by the hydraulic pump 1 can be supplied to the B port of the actuator 3, and the A port of the actuator 3 can return oil.
[0041] As a preferred technical solution of this embodiment, pilot chambers are formed at both ends of the main control valve 2, which are the first pilot chamber and the second pilot chamber respectively, and the pilot oil circuit 20 supplies pilot oil to the first pilot chamber and the second pilot chamber. Reset components are also provided at both ends of the main valve core of the main control valve 2, and the reset components are symmetrically arranged at both ends of the main control valve 2. When the pilot oil circuit 20 stops supplying pilot oil, the main valve core of the main control valve 2 can be reset to the middle position under the action of the reset component, and the oil pumped out by the hydraulic pump 1 flows into the oil tank 5 through the main control valve 2.
[0042] As a preferred technical solution of this embodiment, a sequence valve 4 is also provided on the main oil circuit 10. The sequence valve 4 is located between the hydraulic pump 1 and the main control valve 2. The sequence valve 4 can be used to ensure the minimum pressure of the system, which can meet the minimum pilot pressure required for the switching of the main valve core of the main control valve 2.
[0043] The pilot oil circuit 20 provides pilot oil for the main control valve 2 on the main oil circuit 10. The pilot oil circuit 20 takes oil from the hydraulic pump 1 and then supplies oil to the first pilot chamber and the second pilot chamber of the main control valve 2. A pressure sensing valve 6 is provided on the pilot oil circuit 20. The pressure sensing valve 6 senses the oil pressure of the main oil circuit 10 to control the on and off of the pilot oil circuit 20.
[0044] As a preferred technical solution of this embodiment, one end of the pilot oil circuit 20 is connected to the pump outlet of the hydraulic pump 1, and the other end of the pilot oil circuit 20 is connected to the first pilot chamber and the second pilot chamber respectively.
[0045] As a preferred technical solution of this embodiment, the valve core end of the pressure sensing valve 6 is affected by the oil pressure of the main oil circuit 10. When the oil pressure of the main oil circuit 10 is lower than the preset value, the pressure sensing valve 6 is in the disconnected position, the pilot oil circuit 20 is disconnected, the pilot oil cannot be supplied to the two pilot chambers of the main control valve 2, and the main control valve 2 is reset to the middle position; when the oil pressure of the main oil circuit 10 reaches the preset value, the pressure sensing valve 6 is in the connected position, the pilot oil circuit 20 is connected, and the pilot oil can be supplied to the two pilot chambers of the main control valve 2.
[0046] As a preferred technical solution of this embodiment, the pressure sensing valve 6 can be set as a two-position two-way valve, one end of the valve core of the pressure sensing valve 6 is provided with an elastic member, and the other end forms a pilot chamber, and the pilot chamber takes pressure from the main oil circuit 10. In this embodiment, the pilot chamber takes pressure from the higher oil pressure in the A port and the B port of the actuator 3. Specifically, by setting a shuttle valve 9, one oil inlet of the shuttle valve 9 is connected to the A port of the actuator 3, the other oil inlet of the shuttle valve 9 is connected to the B port of the actuator 3, and the outlet of the shuttle valve 9 is connected to the pilot chamber of the pressure sensing valve 6, and the A port and the B port transmit the highest load pressure to the pilot chamber of the pressure sensing valve 6 through the shuttle valve 9.
[0047] As a preferred technical solution of this embodiment, a pressure reducing valve 8 is further provided on the pilot oil circuit 20 , and the oil after being decompressed by the pressure reducing valve 8 flows to the pressure sensing valve 6 .
[0048] As a preferred technical solution of this embodiment, a solenoid valve 7 is also provided on the pilot oil circuit 20. There are two solenoid valves 7, which are respectively provided for the first pilot chamber and the second pilot chamber. The solenoid valve 7 controls the on-off of the pilot oil flowing out of the pressure sensing valve 6 to the corresponding pilot chamber, controls the oil inlet of the pilot chamber, and further controls the action of the main control valve 2.
[0049] Based on the above structure, in the hydraulic system of this embodiment, when the maximum load pressure is less than the preset pressure value of the pressure sensing valve 6 (taking 18 MPa as an example), the oil at the outlet of the pressure reducing valve 8 provides pilot oil to the two solenoid valves 7 through the pressure sensing valve 6. The two solenoid valves 7 after being energized can control the moving direction of the main valve core of the main control valve, and the main valve core controls the direction of the oil in the main oil circuit 10. The solenoid valve 7 is energized to move the main valve core from the middle position to the working position, and the oil flows to the A port or the B port of the actuator 3;
[0050] When the load pressure at port A or port B is greater than the preset pressure value of the pressure sensing valve 6 (taking 18MPa as an example), the oil at the outlet of the pressure reducing valve 8 is cut off by the pressure sensing valve 6, and cannot provide pilot oil to the two solenoid valves 7. At this time, the main valve core is reset to the middle position under the action of the reset member, and the oil pumped out by the hydraulic pump 1 passes through the sequence valve 4 and the main control valve 2 in turn to reach the oil tank 5, realizing low-pressure unloading and limiting the maximum pressure of the main oil circuit 10.
[0051] Embodiment 2
[0052] like Figure 4 As shown, this embodiment is basically the same as the first embodiment, except that the pilot chamber of the pressure sensing valve 6 takes pressure from the oil pressure in the oil circuit between the hydraulic pump 1 and the main control valve 2 . Specifically, the pilot chamber of the pressure sensing valve 6 takes pressure from the oil pressure at the pump outlet of the hydraulic pump 1. When the oil pressure at the pump outlet of the hydraulic pump 1 is lower than the preset pressure value of the pressure sensing valve 6, the oil at the outlet of the pressure reducing valve 8 provides pilot oil to the two solenoid valves 7 through the pressure sensing valve 6. After being energized, the two solenoid valves 7 can control the movement direction of the main valve core of the main control valve 2. The main valve core controls the direction of the oil in the main oil circuit 10. The solenoid valve 7 is energized to enable the main valve core to move from the middle position to the working position, and the oil flows to the A port or the B port of the actuator 3; when the oil pressure at the pump outlet of the hydraulic pump 1 is greater than the preset pressure value of the pressure sensing valve 6, the oil at the outlet of the pressure reducing valve 8 is cut off by the pressure sensing valve 6, and the pilot oil cannot be provided to the two solenoid valves 7. At this time, the main valve core is reset to the middle position under the action of the reset member, and the oil pumped out of the hydraulic pump 1 passes through the sequence valve 4 and the main control valve 2 in turn to reach the oil tank 5, realizing low-pressure unloading and limiting the maximum pressure of the main oil circuit 10.
[0053] Embodiment 3
[0054] like Figure 5As shown, this embodiment is basically the same as the second embodiment, except that the pilot chamber of the pressure sensing valve 6 takes pressure from the oil pressure of the oil circuit between the sequence valve 4 and the main control valve 2 . When the oil pressure between the sequence valve 4 and the main control valve 2 is lower than the preset pressure value of the pressure sensing valve 6, the oil at the outlet of the pressure reducing valve 8 provides pilot oil to the two solenoid valves 7 through the pressure sensing valve 6. After being energized, the two solenoid valves 7 can control the movement direction of the main valve core of the main control valve 2. The main valve core controls the direction of the oil in the main oil circuit 10. The solenoid valve 7 is energized to move the main valve core from the middle position to the working position, and the oil flows to the A port or B port of the actuator 3; when the oil pressure between the sequence valve 4 and the main control valve 2 is greater than the preset pressure value of the pressure sensing valve 6, the oil at the outlet of the pressure reducing valve 8 is cut off by the pressure sensing valve 6, and the pilot oil cannot be provided to the two solenoid valves 7. At this time, the main valve core is reset to the middle position under the action of the reset member, and the oil pumped out by the hydraulic pump 1 passes through the sequence valve 4 and the main control valve 2 in turn to reach the oil tank 5, realizing low-pressure unloading and limiting the maximum pressure of the main oil circuit 10.
[0055] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.
Claims
1. A hydraulic system, characterized in that: include: A main oil circuit (10), wherein a hydraulic pump (1), a main control valve (2) and an actuator (3) are arranged on the main oil circuit (10), and the oil pumped out by the hydraulic pump (1) supplies oil to the actuator (3) under the control of the main control valve (2); A pilot oil circuit (20), the pilot oil circuit (20) supplies pilot oil to the main control valve (2), a pressure sensing valve (6) is provided on the pilot oil circuit (20), the pressure sensing valve (6) senses the oil pressure of the main oil circuit (10), the pressure sensing valve (6) controls the on-off of the pilot oil circuit (20), and when the oil pressure of the main oil circuit (10) exceeds a preset value, the pressure sensing valve (6) cuts off the pilot oil circuit (20).
2. A hydraulic system according to claim 1, characterized in that: When the main control valve (2) is in the middle position, the oil pumped out by the hydraulic pump (1) is drained through the main control valve (2).
3. A hydraulic system according to claim 1, characterized in that: The valve core of the pressure sensing valve (6) slides under the action of the oil pressure of the main oil circuit (10).
4. A hydraulic system according to claim 3, characterized in that: An elastic member is provided at one end of the valve core of the pressure sensing valve (6), and a pilot chamber is formed at the other end of the valve core of the pressure sensing valve (6), wherein the pilot chamber takes pressure from the main oil circuit (10).
5. A hydraulic system according to claim 4, characterized in that: The pilot chamber of the pressure sensing valve (6) takes pressure from the higher port oil pressure of the two ports of the actuator (3); Alternatively, the pilot chamber of the pressure sensing valve (6) takes pressure from the oil pressure in the oil circuit between the hydraulic pump (1) and the main control valve (2).
6. A hydraulic system according to claim 5, characterized in that: A sequence valve (4) is also provided on the oil circuit between the hydraulic pump (1) and the main control valve (2), and the pilot chamber of the pressure sensing valve (6) takes pressure from the oil pressure at the pump outlet of the hydraulic pump (1); or, the pilot chamber of the pressure sensing valve (6) takes pressure from the oil pressure between the sequence valve (4) and the main control valve (2).
7. A hydraulic system according to any one of claims 1 to 6, characterized in that: One end of the pilot oil circuit (20) is connected to the pump outlet of the hydraulic pump (1), and the other end of the pilot oil circuit (20) is connected to the first pilot chamber and the second pilot chamber at both ends of the main control valve (2). A pressure reducing valve (8) is also provided on the pilot oil circuit (20), and the outlet of the pressure reducing valve (8) is connected to the inlet of the pressure sensing valve (6).
8. A hydraulic system according to claim 7, characterized in that: The pilot oil circuit (20) is also provided with a pressure reducing valve (8), and the pilot oil enters the pressure sensing valve (6) after passing through the pressure reducing valve (8).
9. A hydraulic system according to claim 7, characterized in that: Resetting components are respectively provided at both ends of the main control valve (2).
10. A hydraulic system according to claim 7, characterized in that: It also includes two solenoid valves (7), which are respectively arranged for the first pilot chamber and the second pilot chamber, and the solenoid valves (7) control the oil inlet and outlet of the corresponding pilot chamber.