An adjustable constant pressure control valve

Abstract

The utility model discloses an adjustable constant pressure control valve. The control valve is a two-position three-way reversing valve. The two-position three-way reversing valve comprises a first inlet, a second inlet and a first outlet. The first inlet is connected to a main circuit through a first oil circuit, the second inlet is connected to an oil return tank through a second oil circuit, the first outlet is connected to a pilot circuit through a third oil circuit, the third oil circuit is connected to the oil return tank through a fourth oil circuit, a throttle valve is arranged on the fourth oil circuit, the second oil circuit is connected to the fourth oil circuit through a fifth oil circuit, and a throttle valve is arranged on the second oil circuit.

Description

Technical Field

[0001] The utility model relates to an adjustable constant pressure control valve. Background Art

[0002] The function of the hydraulic system is to increase the force by changing the pressure. A complete hydraulic system consists of five parts, namely power elements, actuators, control elements, auxiliary elements (accessories) and hydraulic oil. Hydraulic systems can be divided into two categories: hydraulic transmission systems and hydraulic control systems. The main function of hydraulic transmission systems is to transmit power and motion.

[0003] In hydraulic systems, a relief valve is usually used to release oil pressure to regulate excessive pressure in the oil circuit. However, frequent opening of the relief valve can easily cause internal energy loss and also make noise. Therefore, a control valve is needed to replace the traditional relief valve to reduce the opening of the relief valve. Utility Model Content

[0004] The purpose of the utility model is to solve the above deficiencies in the prior art and to provide an adjustable constant pressure control valve.

[0005] An adjustable constant pressure control valve, the control valve is a two-position three-way reversing valve, the two-position three-way reversing valve includes a first inlet, a second inlet, and a first outlet, the first inlet is connected to the main circuit through a first oil circuit, the second inlet is connected to the return oil tank through a second oil circuit, the first outlet is connected to the pilot circuit through a third oil circuit, the third oil circuit and the return oil tank are connected through a fourth oil circuit, a throttle valve is provided on the fourth oil circuit, the second oil circuit and the fourth oil circuit are connected through a fifth oil circuit, and a throttle valve is provided on the second oil circuit.

[0006] Preferably, the control valve includes a valve body, a valve stem, and a limit mechanism. The valve body is provided with an inner cavity, a first oil passage, a second oil passage, and a third oil passage that are connected to each other. The first oil passage is connected to the main circuit, the second oil passage is connected to the pilot circuit, and the third oil passage is connected to the oil return tank.

[0007] The valve stem is movably arranged in the inner cavity, the inner cavity is a cylindrical structure, the valve stem is a cylindrical structure, the diameter of the cylinder is smaller than the diameter of the inner cavity, and a shaft shoulder is provided in the middle section of the arc surface on the outer side of the valve stem, and the diameter of the shaft shoulder is the same as the diameter of the inner cavity.

[0008] Preferably, the limiting mechanism includes a main body, a spring seat, a compression spring, a pressure plate, and a push rod. A chamber is provided inside the main body, and openings communicating with the outside are provided at both ends of the chamber. The chambers are sequentially connected to a first chamber, a second chamber, and a third chamber. The front section of the main body is inserted into a fourth chamber inside the valve body.

[0009] The fourth chamber is connected to the inner cavity of the valve body, and the inner diameter of the fourth chamber is larger than the inner diameter of the inner cavity. The spring is located in the first chamber, and its two ends are respectively connected to the spring seat and one side of the pressure plate. The spring seat is located at the bottom of the fourth chamber, and the other side of the spring seat is connected to the top of the valve stem, and the other side of the pressure plate is connected to one end of the push rod. The pressure plate is located in the second chamber, and the push rod is inserted into the third chamber, and the push rod is fixed in the third chamber by a fixing structure.

[0010] Preferably, the fixing structure includes a locking nut, the outer side surface of the rear section of the push rod is provided with a thread, the push rod is threadedly connected to the inner wall of the third chamber and is locked by the locking nut.

[0011] Preferably, a groove is provided on the outer side wall of the push rod, and a sealing ring is provided in the groove.

[0012] Preferably, a throttle pin is provided between the second oil passage and the third oil passage.

[0013] Beneficial effects: Compared with the prior art, the utility model releases the oil pressure by connecting the main circuit and the pilot circuit of the axial piston variable pump, so that the pressure of the hydraulic system is constant. When the system pressure reaches the set value, the oil flows in from the A port to push the valve stem to open. After opening, the oil flows out from the B port to push the hydraulic cylinder, reduce the swing tilt angle, reduce the displacement, and then reduce the system output flow, so that the system pressure no longer rises and stabilizes at the set value;

[0014] By turning the adjusting screw, the system pressure setting value can be changed so that the system pressure when the plunger pump is working can be stabilized at the expected value required to adapt to the working conditions. The existence of the throttle pin is to enable the pilot circuit to return oil stably and slowly when the valve stem is closed, so that the entire circuit can achieve dynamic balance. This structure is simple, versatile, and has stable performance. It can avoid frequent opening of the system overflow valve and has outstanding performance in reducing internal energy loss and noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the internal structure of an adjustable constant pressure control valve;

[0016] Figure 2 It is a schematic diagram of the principle of an adjustable constant pressure control valve;

[0017] In the figure, 1, valve body, 2, valve stem, 3, spring seat, 4, first compression spring, 5, second compression spring, 6, main body, 7, pressure plate, 8, push rod, 9, throttling pin, 10, first oil circuit, 11, second oil circuit, 12, third oil circuit, 13, fourth oil circuit, 14, fifth oil circuit. DETAILED DESCRIPTION

[0018] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with embodiments and drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0019] like Figure 1-2 As shown, valve body 1, valve stem 2, spring seat 3, first compression spring 4, second compression spring 5, main body 6, pressure plate 7, push rod 8, throttle pin 9, first oil circuit 10, second oil circuit 11, third oil circuit 12, fourth oil circuit 13, fifth oil circuit 14;

[0020] Embodiment 1: Working principle:

[0021] like Figure 1 As shown, an adjustable constant pressure control valve is a two-position three-way reversing valve, the two-position three-way reversing valve includes a first inlet, a second inlet, and a first outlet, the first inlet is connected to the main circuit through a first oil circuit 10, the second inlet is connected to the return oil tank through a second oil circuit 11, the first outlet is connected to the pilot circuit through a third oil circuit 12, the third oil circuit 12 is connected to the return oil tank through a fourth oil circuit 13, a throttle valve is provided on the fourth oil circuit 13, the second oil circuit 11 is connected to the fourth oil circuit 13 through a fifth oil circuit 14, and a throttle valve is provided on the second oil circuit 11.

[0022] Embodiment 2: Specific structure:

[0023] like Figure 2 As shown, the control valve includes a valve body 1, a valve stem 2, and a limit mechanism. The valve body 1 is provided with a connected inner cavity, a first oil passage (port A in the figure), a second oil passage (port B in the figure), and a third oil passage (port C in the figure). The first oil passage is connected to the main circuit, the second oil passage is connected to the pilot circuit, the third oil passage is connected to the return oil tank, and a throttling pin 9 is provided between the second oil passage and the third oil passage.

[0024] The valve stem 2 is movably arranged in the inner cavity, the inner cavity is a cylindrical structure, the valve stem 2 is a cylindrical structure, the diameter of the cylinder is smaller than the diameter of the inner cavity, and a shaft shoulder is provided in the middle section of the outer arc surface of the valve stem 2, and the diameter of the shaft shoulder is the same as the diameter of the inner cavity.

[0025] In this embodiment, the limiting mechanism includes a main body 6, a spring seat 3, a compression spring, a pressure plate 7, and a push rod 8. A chamber is provided inside the main body 6. Both ends of the chamber are provided with openings communicating with the outside. The chambers are sequentially connected to the first chamber, the second chamber, and the third chamber. The front section of the main body 6 is inserted into the fourth chamber inside the valve body 1. The compression spring includes a first compression spring 4 and a second compression spring 5. The pressure requirement can be met by the two compression springs.

[0026] The fourth chamber is connected to the inner cavity of the valve body 1, and the inner diameter of the fourth chamber is larger than the inner diameter of the inner cavity. The spring is located in the first chamber, and the two ends are respectively connected to the spring seat 3 and one side of the pressure plate 7. The spring seat 3 is located at the bottom of the fourth chamber, and the other side of the spring seat 3 is connected to the top of the valve stem 2. The other side of the pressure plate 7 is connected to one end of the push rod 8. The pressure plate 7 is located in the second chamber, and the push rod 8 is penetrated into the third chamber. The push rod 8 is fixed in the third chamber by a threaded connection structure. A groove is provided on the outer wall of the push rod 8, and a sealing ring is provided in the groove. A thread is provided on the outer side of the rear section of the push rod 8. The push rod 8 is threadedly connected to the inner wall of the third chamber and is locked by a locking nut.

[0027] Instructions for use: When the system pressure reaches the set value, the oil flows in from port A to push the valve stem to open. After opening, the oil flows out from port B to push the hydraulic cylinder, reduce the swing tilt angle, reduce the displacement, and then reduce the system output flow, so that the system pressure no longer rises and stabilizes at the set value.

[0028] By turning the push rod, the system pressure setting value can be changed, so that the system pressure when the plunger pump is working can be stabilized at the expected value required to adapt to the working conditions. The existence of the throttle pin is to ensure that the pilot circuit can return oil stably and slowly when the valve stem is closed, so that the entire circuit can achieve dynamic balance.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An adjustable constant pressure control valve, characterized in that: The control valve is a two-position three-way reversing valve, which includes a first inlet, a second inlet, and a first outlet. The first inlet is connected to the main circuit through a first oil circuit, the second inlet is connected to the return oil tank through a second oil circuit, the first outlet is connected to the pilot circuit through a third oil circuit, the third oil circuit and the return oil tank are connected through a fourth oil circuit, a throttle valve is provided on the fourth oil circuit, the second oil circuit and the fourth oil circuit are connected through a fifth oil circuit, and a throttle valve is provided on the second oil circuit.

2. An adjustable constant pressure control valve according to claim 1, characterized in that: The control valve comprises a valve body, a valve stem, and a limit mechanism. The valve body is provided with an inner cavity, a first oil passage, a second oil passage, and a third oil passage that are connected to each other. The first oil passage is connected to the main circuit, the second oil passage is connected to the pilot circuit, and the third oil passage is connected to the oil return tank. The valve stem is movably arranged in the inner cavity, the inner cavity is a cylindrical structure, the valve stem is a cylindrical structure, the diameter of the cylinder is smaller than the diameter of the inner cavity, and a shaft shoulder is provided in the middle section of the outer arc surface of the valve stem, and the diameter of the shaft shoulder is the same as the diameter of the inner cavity.

3. An adjustable constant pressure control valve according to claim 2, characterized in that: The limiting mechanism comprises a main body, a spring seat, a compression spring, a pressure plate, and a push rod. A chamber is arranged inside the main body, and openings communicating with the outside are arranged at both ends of the chamber. The chambers are sequentially connected to a first chamber, a second chamber, and a third chamber. The front section of the main body is inserted into a fourth chamber inside the valve body. The fourth chamber is connected to the inner cavity of the valve body, and the inner diameter of the fourth chamber is larger than the inner diameter of the inner cavity. The spring is located in the first chamber, and its two ends are respectively connected to the spring seat and one side of the pressure plate. The spring seat is located at the bottom of the fourth chamber, and the other side of the spring seat is connected to the top of the valve stem, and the other side of the pressure plate is connected to one end of the push rod. The pressure plate is located in the second chamber, and the push rod is penetrated into the third chamber, and the push rod is fixed in the third chamber by a fixing structure.

4. The adjustable constant pressure control valve according to claim 3, characterized in that: The fixing structure comprises a locking nut, the outer side surface of the rear section of the push rod is provided with a thread, the push rod is threadedly connected to the inner wall of the third chamber and is locked by the locking nut.

5. The adjustable constant pressure control valve according to claim 4, characterized in that: The outer side wall of the push rod is provided with a clamping groove, and a sealing ring is arranged in the clamping groove.

6. The adjustable constant pressure control valve according to claim 4, characterized in that: A throttling pin is arranged between the second oil passage and the third oil passage.

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