Constant pressure hydraulic system control valve group

Abstract

The utility model discloses a constant pressure hydraulic system control valve group, including valve body, the unloading valve, check valve, electromagnetic overflow valve and electromagnetic reversing valve are installed on the valve body, the oil port P of valve body is connected with the oil inlet of check valve, and the oil channel between oil port P and check valve oil inlet still respectively with the oil port M1 of valve body, the oil inlet of unloading valve is connected, the oil outlet of check valve is connected with the oil inlet P1 of electromagnetic reversing valve, and the oil channel between check valve oil outlet and electromagnetic reversing valve oil inlet P1 still respectively with the oil inlet P2 of electromagnetic overflow valve and the oil port M2 of valve body, oil port A, oil port Y are connected, the oil port A1 of electromagnetic reversing valve is connected with the oil port B of valve body, and the oil port T3 of electromagnetic reversing valve is connected with the oil port T2 of valve body, the oil port T1 of valve body is connected with the oil port T4 of electromagnetic overflow valve, the oil outlet of unloading valve respectively, the control port of valve body is connected with the control port of unloading valve, and the control port of valve body is connected with the control port of electromagnetic overflow valve.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic control technology, specifically a control valve group for a constant pressure hydraulic system. Background Technology

[0002] Railway transportation is the most important mode of transport in my country. As the component that comes into direct contact with the wheels, the surface condition of the rails directly affects the comfort and safety of train travel. Therefore, rails require regular grinding and maintenance. Rail milling machines remove defects from the rail surface through milling. Their operating speed ranges from 0.3 to 2 km / h and can be infinitely adjusted according to the technical condition of the rails.

[0003] Due to its low operating speed and wide speed range, traditional closed-loop travel systems can no longer meet its operational requirements, necessitating the use of high-performance electro-proportional valves for speed control. However, system pressure fluctuations significantly impact speed control accuracy, therefore a constant pressure system must be employed in the oil supply system.

[0004] The maximum operating speed is nearly seven times the minimum operating speed. If a constant pressure pump is used, the pump's output displacement is extremely low at a travel speed of 0.3 km / h, making speed control difficult. Therefore, it is necessary to design a system that uses a hydraulic control valve assembly in conjunction with a fixed displacement pump to achieve a constant pressure system. This not only ensures control accuracy at low speeds but also reduces the cost of using a constant pressure pump. Utility Model Content

[0005] To address the shortcomings of existing technologies, the purpose of this utility model is to provide a constant pressure hydraulic system control valve group that meets the constant pressure speed regulation requirements of the system at low flow rates while being less expensive than using a constant pressure pump.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a constant pressure hydraulic system control valve assembly, comprising a valve body, on which an unloading valve, a check valve, a solenoid relief valve, and a solenoid directional valve are installed; the valve body includes ten external oil ports, namely oil port A, oil port B, oil port P, oil port T1, oil port T2, oil port M1, oil port M2, oil port X, oil port Y, and oil port L; oil port P of the valve body is connected to the oil inlet of the check valve, and the oil passage between oil port P and the oil inlet of the check valve is also connected to oil port M1 of the valve body and the oil inlet of the unloading valve respectively; the outlet of the check valve... The oil port is connected to the oil inlet P1 of the solenoid directional valve, and the oil passage between the oil outlet of the check valve and the oil inlet P1 of the solenoid directional valve is also connected to the oil inlet P2 of the solenoid relief valve, as well as the oil ports M2, A, and Y of the valve body; the oil port A1 of the solenoid directional valve is connected to the oil port B of the valve body, and the oil port T3 of the solenoid directional valve is connected to the oil port T2 of the valve body; the oil port T1 of the valve body is connected to the oil port T4 of the solenoid relief valve and the oil outlet of the unloading valve; the oil port X of the valve body is connected to the control port of the unloading valve; and the oil port L of the valve body is connected to the control port of the solenoid relief valve.

[0007] A further improvement is that a throttle valve is also installed on the valve body, and the throttle valve is located in the oil passage between the solenoid directional valve oil port T3 and the valve body oil port T2.

[0008] A further improvement is that the oil port P of the valve body is connected to the oil outlet of a hydraulic pump.

[0009] A further improvement is that the oil port A of the valve body is connected to the oil inlet of the operating system.

[0010] A further improvement is that the oil port B and oil port X of the valve body are connected to the external accumulator charging port.

[0011] A further improvement is that the oil port T2 of the valve body is connected to the oil inlet of the hydraulic oil radiator.

[0012] A further improvement is that the oil port T1 and oil port L of the valve body are connected to an external hydraulic oil tank.

[0013] A further improvement is made in that: the oil port M1 and oil port M2 of the valve body are connected to external pressure testing connectors.

[0014] A further improvement is made in that an external pressure sensor is connected to the oil port Y of the valve body.

[0015] A further improvement is that the solenoid directional valve is a two-position three-way solenoid valve, and the oil inlet P1 is normally closed.

[0016] The beneficial effects of this utility model are as follows:

[0017] The valve assembly provided by this utility model can replace the constant pressure pump to provide a constant pressure oil source for the working system. It meets the constant pressure speed regulation requirements of the system when the flow rate is small, while the cost is lower than that of using a constant pressure pump. It has the advantages of high efficiency, low heat generation, low cost, stable system pressure, and the ability to absorb hydraulic shock. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the control valve group of the constant pressure hydraulic system in an embodiment of this utility model;

[0019] Figure 2 This is a front view of the control valve assembly of the constant pressure hydraulic system in an embodiment of this utility model;

[0020] Figure 3 This is a rear view of the control valve assembly of the constant pressure hydraulic system in an embodiment of this utility model;

[0021] Figure 4 This is a top view of the control valve assembly of the constant pressure hydraulic system in an embodiment of this utility model.

[0022] Figure label:

[0023] 1-Valve body; 2-Unloading valve; 3-Check valve; 4-Solenoid relief valve; 5-Solenoid directional valve; 6-Throttle valve. Detailed Implementation

[0024] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0025] In the description of this utility model, it should be noted that the directional terms such as "center", "horizontal (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this utility model.

[0026] The following description, in conjunction with the accompanying drawings, further illustrates specific embodiments of the present invention, making the technical solution and beneficial effects of the present invention clearer and more explicit. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0027] See Figures 1-4 As shown, this utility model embodiment provides a constant pressure hydraulic system control valve group, including a valve body 1, on which an unloading valve 2, a check valve 3, an electromagnetic relief valve 4 and an electromagnetic directional valve 5 are installed;

[0028] The valve body 1 includes ten external oil ports, namely oil port A, oil port B, oil port P, oil port T1, oil port T2, oil port M1, oil port M2, oil port X, oil port Y and oil port L;

[0029] The oil port P of valve body 1 is connected to the oil inlet of check valve 3, and the oil passage between oil port P and oil inlet of check valve 3 is also connected to oil port M1 of valve body 1 and oil inlet of unloading valve 2 respectively.

[0030] The oil outlet of the one-way valve 3 is connected to the oil inlet P1 of the solenoid directional valve 5, and the oil passage between the oil outlet of the one-way valve 3 and the oil inlet P1 of the solenoid directional valve 5 is also connected to the oil inlet P2 of the solenoid relief valve 4, as well as the oil inlet M2, oil inlet A and oil inlet Y of the valve body 1.

[0031] The oil port A1 of the solenoid directional valve 5 is connected to the oil port B of the valve body 1, and the oil port T3 of the solenoid directional valve 5 is connected to the oil port T2 of the valve body 1.

[0032] The oil port T1 of valve body 1 is connected to the oil port T4 of electromagnetic relief valve 4 and the oil outlet of unloading valve 2, respectively.

[0033] The oil port X of valve body 1 is connected to the control port of unloading valve 2;

[0034] The oil port L of valve body 1 is connected to the control port of electromagnetic relief valve 4.

[0035] Specifically, a throttle valve 6 is also installed on the valve body 1. The throttle valve 6 is located in the oil passage between the oil port T3 of the solenoid directional valve 5 and the oil port T2 of the valve body 1. The throttle valve 6 is used to absorb the hydraulic shock when the accumulator is unloaded. It can be a fixed throttle orifice joint or a throttle valve.

[0036] Specifically, port P of valve body 1 is connected to the hydraulic pump outlet. Port A of valve body 1 is connected to the operating system inlet. Ports B and X of valve body 1 are connected to the accumulator charging port. Port T2 of valve body 1 is connected to the hydraulic oil radiator inlet. Ports T1 and L of valve body 1 are connected to the hydraulic oil tank. Ports M1 and M2 of valve body 1 are connected to pressure testing connectors to measure the hydraulic pump outlet pressure and system operating pressure, respectively. Port Y of valve body 1 is connected to a pressure sensor to display the operating system pressure in real time.

[0037] Specifically, the solenoid directional valve 5 is a two-position three-way solenoid valve, and the oil inlet P1 is normally closed. When the solenoid valve is de-energized, the accumulator is unloaded through this valve.

[0038] Specifically, the unloading pressure of the unloading valve 2 can be adjusted by the mechanical handwheel on the valve. The nominal pressure difference between the opening and closing of the valve is 15% of the set value, and its unloading oil inlet X is connected to the accumulator charging port. In this embodiment, the set pressure of the unloading valve is 21 MPa, and the nominal pressure difference between the opening and closing of the valve core is 3.15 MPa.

[0039] Specifically, the electromagnetic relief valve 4 is a pilot-operated electromagnetic relief valve that unloads upon energization. The set pressure of the pilot-operated electromagnetic relief valve is 2 MPa higher than that of the unloading valve. In this embodiment, the set pressure of the electromagnetic relief valve is 23 MPa.

[0040] The constant pressure control process of the control valve group in this constant pressure hydraulic system is as follows:

[0041] Operating conditions: The oil pump starts working, the solenoid relief valve is energized to build pressure, the accumulator-controlled solenoid directional valve is energized, and the unloading valve is in the closed state. The pump output flow supplies oil to the working system through valve body port A, and the accumulator is charged through the solenoid valve controlled by the accumulator and valve body port B. The accumulator pressure is connected to valve body port X through a pipeline, and its pressure signal acts on the unloading valve. When the system pressure reaches the unloading valve's set value of 21MPa, the unloading valve spool opens, and excess flow enters the radiator for cooling through the unloading valve and valve body port T1. The opening degree of the unloading valve spool changes according to the system flow demand to ensure a constant system pressure. The solenoid relief valve is in the closed state, acting as a system safety valve.

[0042] Non-operating conditions: Construction machinery often uses an engine to drive a travel pump, a working pump, and a cooling pump via a transfer case. During non-operating periods, the working pump needs to be unloaded, while the travel and cooling pumps remain unloaded. At this time, the solenoid relief valve de-energizes and unloads, allowing all the working pump's output flow to enter the radiator via the relief valve. The accumulator control solenoid valve unloads, and the pressurized oil in the accumulator enters the hydraulic tank via the throttle valve. The unloading valve control pressure returns to zero, and the unloading valve is in the closed position.

[0043] In the description of this specification, references to terms such as "an embodiment," "preferred," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. Illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0044] Based on the above description of the structure and principle, those skilled in the art should understand that this utility model is not limited to the specific embodiments described above. Improvements and substitutions based on this utility model using techniques known in the art all fall within the protection scope of this utility model and should be defined by the claims.

Claims

1. A control valve assembly for a constant pressure hydraulic system, comprising a valve body (1), characterized in that: The valve body (1) is equipped with an unloading valve (2), a check valve (3), an electromagnetic overflow valve (4), and an electromagnetic directional valve (5); The valve body (1) includes ten external oil ports, namely oil port A, oil port B, oil port P, oil port T1, oil port T2, oil port M1, oil port M2, oil port X, oil port Y and oil port L; The oil port P of the valve body (1) is connected to the oil inlet of the check valve (3), and the oil passage between the oil port P and the oil inlet of the check valve (3) is also connected to the oil port M1 of the valve body (1) and the oil inlet of the unloading valve (2). The oil outlet of the check valve (3) is connected to the oil inlet P1 of the solenoid directional valve (5), and the oil passage between the oil outlet of the check valve (3) and the oil inlet P1 of the solenoid directional valve (5) is also connected to the oil inlet P2 of the solenoid relief valve (4), as well as the oil inlet M2, oil inlet A and oil inlet Y of the valve body (1). The oil port A1 of the electromagnetic reversing valve (5) is connected to the oil port B of the valve body (1), and the oil port T3 of the electromagnetic reversing valve (5) is connected to the oil port T2 of the valve body (1). The oil port T1 of the valve body (1) is connected to the oil port T4 of the electromagnetic overflow valve (4) and the oil outlet of the unloading valve (2), respectively. The oil port X of the valve body (1) is connected to the control port of the unloading valve (2); The oil port L of the valve body (1) is connected to the control port of the electromagnetic relief valve (4).

2. The constant pressure hydraulic system control valve assembly according to claim 1, characterized in that: A throttle valve (6) is also installed on the valve body (1), and the throttle valve (6) is located on the oil passage between the oil port T3 of the electromagnetic reversing valve (5) and the oil port T2 of the valve body (1).

3. The constant pressure hydraulic system control valve assembly according to claim 1, characterized in that: The oil port P of the valve body (1) is connected to the oil outlet of an external hydraulic pump.

4. The constant pressure hydraulic system control valve assembly according to claim 1, characterized in that: The oil port A of the valve body (1) is connected to the oil inlet of the external working system.

5. The constant pressure hydraulic system control valve assembly according to claim 1, characterized in that: The oil port B and oil port X of the valve body (1) are connected to the accumulator charging port.

6. The constant pressure hydraulic system control valve assembly according to claim 1, characterized in that: The oil port T2 of the valve body (1) is connected to the oil inlet of the hydraulic oil radiator.

7. The constant pressure hydraulic system control valve assembly according to claim 1, characterized in that: The oil port T1 and oil port L of the valve body (1) are connected to the external hydraulic oil tank.

8. The constant pressure hydraulic system control valve assembly according to claim 1, characterized in that: The valve body (1) has external pressure testing connectors for its oil ports M1 and M2.

9. The constant pressure hydraulic system control valve assembly according to claim 1, characterized in that: The oil port Y of the valve body (1) is connected to an external pressure sensor.

10. The constant pressure hydraulic system control valve assembly according to claim 1, characterized in that: The solenoid directional valve (5) is a two-position three-way solenoid valve, and the oil inlet P1 is normally closed.

Images