Main control valve for propeller with adjustable pitch capable of improving midship unloading capacity

Abstract

The application discloses a main control valve with improved mid-position unloading capacity for a pitch control propeller, and belongs to the technical field of hydraulic slide valves. The main control valve comprises a valve core and a valve sleeve in a hollow structure. The valve core is provided with two shoulders. Throttle grooves are formed in the facing sides of the two shoulders. A through hole is formed in the position close to the outer side of each shoulder, and the through hole is used for high-pressure oil injection. The valve sleeve is provided with a flow distribution window A, a flow distribution window B and a flow distribution window T. The flow distribution window A and the flow distribution window B are control ports, and the flow distribution window A and the flow distribution window B are respectively connected with external oil paths. The flow distribution window T is an oil return port and is connected with an intermediate oil path. One shoulder and the flow distribution window A form a left control chamber of the main control valve, and the other shoulder and the flow distribution window B form a right control chamber of the main control valve. The structure can adapt the area gradient of the throttle grooves to the change rule of the valve port opening degree to complex working conditions, reduce the pressure of the left and right control chambers when the main control valve is in the mid-position, and further improve the mid-position unloading capacity of the main control valve.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydraulic slide valve, and particularly relates to a main control valve for a variable pitch propeller with improved mid-position unloading capacity. BACKGROUND

[0002] The hydraulic slide valve is a main control component in a hydraulic servo system, and plays a crucial role in controlling the flow, pressure and flow direction of the oil medium in the system. The main components of the hydraulic slide valve include a valve core and a valve sleeve.

[0003] The hydraulic slide valve controls fluid power through mechanical movement. The basic working principle is to control the flow and pressure of hydraulic oil by using the throttling principle, that is, by changing the relative movement of the valve core and the valve sleeve to change the throttling area of the flow window, and then to change the flow and pressure of the fluid.

[0004] According to the number of controllable throttling openings formed by the axial displacement of the valve core and the valve sleeve, the slide valve can be divided into four-edge slide valve, double-edge slide valve and single-edge slide valve: the four-edge slide valve has four controllable throttling openings; the double-edge slide valve has two controllable throttling openings; and the single-edge slide valve has only one controllable throttling opening. According to the geometric combination of the valve core shoulder and the valve sleeve flow window at zero position, the slide valve can be divided into negative opening (positive overlap), zero opening (zero overlap) and positive opening (negative overlap) three forms: the valve core shoulder width of the negative opening slide valve is greater than the valve sleeve flow window width, forming a geometric positive overlap of the axial size of the valve core and the valve sleeve; the valve core shoulder width of the zero opening slide valve is equal to the valve sleeve flow window width, forming a geometric zero overlap of the axial size of the valve core and the valve sleeve; and the valve core shoulder width of the positive opening slide valve is less than the valve sleeve flow window width, forming a geometric negative overlap of the axial size of the valve core and the valve sleeve.

[0005] The main control valve for the variable pitch propeller belongs to the positive opening four-edge slide valve, that is, at zero position, the valve core shoulder and the valve sleeve flow window form four geometric negative overlaps of equal axial size. When the variable pitch propeller system receives a variable pitch command, according to the change of the relative movement of the valve core and the valve sleeve, the working position of the main control valve can be divided into left position, right position and middle position, and the working position corresponds to the working state of the variable pitch propeller system: when the main control valve is in the left position, the variable pitch propeller system is in the ahead state; when the main control valve is in the right position, the variable pitch propeller system is in the astern state; and when the main control valve is in the middle position, the variable pitch propeller system is in the constant pitch state. During the navigation of the ship, the variable pitch propeller system does not need to frequently perform the ahead and astern, and usually one working condition corresponds to one pitch, so the variable pitch propeller system is mostly in the constant pitch state, that is, the main control valve is in the middle position, at this time the oil fills the external oil circuit, and the pressures of the two external oil circuits are approximately equal to the pressures of the left and right control chambers of the main control valve, if the pressure is too high, it will cause the external oil pipe to be broken and a series of failure behaviors.

[0006] The main control valve is a throttle groove slide valve, a throttle groove is formed on a convex shoulder of a valve core, different shapes of the throttle groove have different functions of the flow area and the relative displacement of the valve core and the valve sleeve, that is, the area gradient changes with the valve port opening, and then the flow and the flow rate of the valve port change. The throttle groove slide valve has the advantages of large hydraulic radius of the valve port, good regulation performance, relatively easy control of the area gradient, and difficulty in blocking. Because the structure size of the throttle groove is very small, the change of the key structure size parameter of the throttle groove will affect the entire hydraulic system. At the same time, the valve core of the slide valve is subjected to various different types of forces in operation, such as hydraulic pressure, hydraulic force, hydraulic lateral force and friction force. The generation of the hydraulic force is because the flow direction and the flow rate change when the liquid flows through the throttle groove valve port, so that the momentum of the liquid changes, and the valve core is subjected to an additional force, the direction of the force is towards the direction of closing the valve port. According to the force balance on the valve core, the size of the hydraulic force will affect the size of the hydraulic pressure and the hydraulic lateral force, and then affect the pressures of the left and right control cavities when the slide valve is in the middle position. The common throttle groove slide valve generally sets an annular groove with a rectangular cross section on the valve core, so as to effectively eliminate the steady-state hydraulic force, and then reduce the pressures of the left and right control cavities of the slide valve.

[0007] The single-stage throttle groove structure is relatively simple, and the area gradient changes with the valve port opening in a relatively single rule, for example, the area gradient of the rectangular throttle groove does not change with the valve port opening, the area gradient of the triangular throttle groove is linearly related to the valve port opening, and the area gradient of the trapezoidal throttle groove is simply a quadratic function of the valve port opening. For a hydraulic system with relatively simple motion, the single change rule of the area gradient can meet the requirements of eliminating the steady-state hydraulic force and reducing the pressures of the left and right control cavities. However, for a complex hydraulic system such as the pitch control system, the single-stage throttle groove cannot well meet the requirements of eliminating the steady-state hydraulic force and reducing the pressures of the left and right control cavities, and therefore it is one of the problems to be solved by those skilled in the art to design a new combined throttle groove, so that the change rule of the area gradient of the throttle groove with the valve port opening adapts to complex working conditions and reduces the pressures of the left and right control cavities. SUMMARY

[0008] The purpose of the present application is to provide a main control valve for a pitch control system, which can improve the mid-position unloading capacity and adapt to complex working conditions, and reduce the pressures of the left and right control cavities when the main control valve is in the middle position.

[0009] According to a first aspect of the embodiments of the present application, a main control valve for a pitch control system is provided, which can improve the mid-position unloading capacity, and the main control valve comprises: a valve core and a valve sleeve with a hollow structure;

[0010] The valve core is provided with two convex shoulders, and a throttle groove is formed on the side facing each other of the two convex shoulders. The valve core is provided with a through hole at a position close to the outer side of each convex shoulder, and the through hole is used for high-pressure oil injection.

[0011] The valve sleeve is provided with a flow distribution window A, a flow distribution window B and a flow distribution window T, the flow distribution window A and the flow distribution window B are control ports, the flow distribution window A and the flow distribution window B are in communication with external oil paths respectively, and the flow distribution window T is an oil return port in communication with an intermediate oil path.

[0012] One of the shoulders forms a left control chamber of the main control valve with the flow distribution window A, and the other shoulder forms a right control chamber of the main control valve with the flow distribution window B.

[0013] In some optional embodiments of the present application, the main control valve is a positive opening equal four-edge spool valve.

[0014] The two shoulders are a first shoulder and a second shoulder respectively.

[0015] When the main control valve is in zero position, the four geometric negative overlap amounts formed in the axial direction between the first shoulder, the second shoulder, the flow distribution window A and the flow distribution window B are equal.

[0016] In some optional embodiments of the present application, the performance of the main control valve is evaluated by using a mid-position unloading capacity.

[0017] The mid-position unloading capacity is the pressure of the left control chamber and the right control chamber when the main control valve is in the mid-position.

[0018] The smaller the pressure value is, the smaller the mid-position unloading capacity is.

[0019] In some optional embodiments of the present application, a combined throttling groove is formed on the shoulder.

[0020] The combined throttling groove is a combination of a trapezoidal throttling groove and a rectangular throttling groove, the depth of the combined throttling groove remains unchanged in the trapezoidal throttling area, and the depth of the combined throttling groove linearly increases from a minimum value to a maximum value in the rectangular throttling area.

[0021] The above technical solutions of the present application have the following beneficial technical effects:

[0022] The main control valve structure of the embodiments of the present application can adapt the area gradient of the throttling groove to the change rule of the valve port opening degree under complex working conditions, reduce the pressure of the left control chamber and the right control chamber when the main control valve is in the mid-position, and thus can improve the mid-position unloading capacity of the main control valve. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a sectional view of the main control valve in an exemplary embodiment of the present application;

[0024] Figure 2 is a principle diagram of the main control valve in a exemplary embodiment of the present application in the mid-position;

[0025] Figure 3 is a structural schematic diagram of a valve core with a trapezoidal throttling groove in an exemplary embodiment of the present application;

[0026] Figure 4 is a structural schematic diagram of a combined throttle groove spool in an exemplary embodiment of the present application;

[0027] Figure 5 is a working principle diagram of a propeller pitch system in an exemplary embodiment of the present application;

[0028] Figure 6 is a left control chamber pressure diagram of a port A of a distribution window when a main control valve is in a neutral position in an exemplary embodiment of the present application;

[0029] Figure 7 is a right control chamber pressure diagram of a port B of a distribution window when a main control valve is in a neutral position in an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application with reference to the specific embodiments and the accompanying drawings. It should be understood that the description is only exemplary and is not intended to limit the scope of the present application. In addition, in the following description, the description of the known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0031] In the accompanying drawings, schematic diagrams of layer structures according to embodiments of the present application are shown. These drawings are not drawn to scale, in which certain details are exaggerated for the purpose of clarity, and certain details can be omitted. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are only exemplary, and in actuality, they can deviate due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes and relative positions can be additionally designed by those skilled in the art according to actual needs.

[0032] Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application.

[0033] In the description of the present application, it should be noted that the terms “first”, “second”, “third” are only for the purpose of description, and cannot be understood or implied as indicating or suggesting relative importance.

[0034] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0035] In the following, with reference to the accompanying drawings, a main control valve for a propeller pitch system with improved neutral unloading capability is described in detail through specific embodiments and application scenarios.

[0036] In a first aspect of the embodiments of the present application, a main control valve for a controllable pitch propeller with improved mid-position unloading capacity is provided, which comprises a valve core 1 and a valve sleeve 2 in a hollow structure;

[0037] The valve core is provided with two shoulders, and a throttle groove is formed on the side of the two shoulders facing each other, and a through hole is formed on the outer side of each shoulder for high-pressure oil injection;

[0038] The valve sleeve is provided with a flow distribution window A 5, a flow distribution window B 7, and a flow distribution window T 6, the flow distribution window A 5 and the flow distribution window B 7 are control ports, and the flow distribution window A 5 and the flow distribution window B 7 are respectively connected with external oil paths, and the flow distribution window T 6 is an oil return port connected with an intermediate oil path;

[0039] One shoulder and the flow distribution window A 5 form a left control chamber of the main control valve, and the other shoulder and the flow distribution window B 7 form a right control chamber of the main control valve.

[0040] Specifically, as shown in the figure, Figure 1 The main control valve for the controllable pitch propeller belongs to a positive opening four-edge slide valve, that is, when in zero position, the shoulder and the flow distribution window of the valve sleeve 2 form four geometric negative overlaps with equal axial dimensions. The inner side of the two shoulders of the valve core 1 is provided with four throttle grooves in the circumferential direction, and two through holes are formed at the inner circumferential position close to the outer side of the shoulder, which can be regarded as P ports 8 for high-pressure oil injection. The valve sleeve 2 is processed with three flow distribution windows, which are flow distribution window A 5, flow distribution window B 7, and flow distribution window T 6. The flow distribution window A 5 and the flow distribution window B 7 are control ports connected with the first external oil path 3 and the second external oil path 4 respectively.

[0041] The structure of the main control valve for the controllable pitch propeller in the embodiment can adapt the area gradient of the throttle groove to the change rule of the valve port opening degree under complex working conditions, reduce the pressure in the left and right control chambers when the main control valve is in the mid-position, and thus improve the mid-position unloading capacity of the main control valve.

[0042] The principle is as follows, Figure 2As shown, when the propeller pitch system receives a variable pitch instruction, according to the change of the relative movement between the valve core 1 and the valve sleeve 2, the working position of the main control valve can be divided into left position, right position and middle position: when the valve core 1 moves right relative to the valve sleeve 2, the flow area of P port 8 to distribution window A port 5 becomes larger, the flow area of P port 8 to distribution window B port 7 becomes smaller, and high-pressure oil mainly flows to the left control chamber, then flows to the load hydraulic cylinder through the first external oil path 3, at this time the main control valve is in the left position; when the valve core 1 moves left relative to the valve sleeve 2, the flow area of P port 8 to distribution window B port 7 becomes larger, the flow area of P port 8 to distribution window A port 5 becomes smaller, and high-pressure oil mainly flows to the right control chamber, then flows to the load hydraulic cylinder through the second external oil path 4; when the relative position of the valve core 1 relative to the valve sleeve 2 does not change, the flow area of P port 8 to distribution window A port 5 and distribution window B port 7 basically no longer changes, high-pressure oil flows to the left and right control chambers, then flows to distribution window T port 6 through the shoulder orifice, and flows back to the tank through the middle oil path, at this time the main control valve is in the middle position.

[0043] In some embodiments, the performance of the main control valve is evaluated by the middle unloading capacity;

[0044] The middle unloading capacity is the pressure of the left control chamber and the right control chamber when the main control valve is in the middle position;

[0045] The smaller the pressure value is, the smaller the middle unloading capacity is.

[0046] When the main control valve is in the middle position, the propeller pitch system is in the steady pitch state, at this time the flow area of P port 8 to distribution window A port 5 and distribution window B port 7 basically no longer changes, and the oil fills the first external oil path 3 and the second external oil path 4, at this time the pressure of the two external oil paths, the first external oil path 3 and the second external oil path 4, is approximately equal to the pressure of the left and right control chambers of the main control valve, that is, PA and PB, if the pressure is too high, it will cause a series of failure behaviors such as rupture of the first external oil path 3 and the second external oil path 4. Therefore, the middle unloading capacity index is introduced in the performance evaluation of the main control valve, that is, the pressure PA and PB of the left and right control chambers when the main control valve is in the middle position: the smaller the pressure PA and PB of the left and right control chambers when the main control valve is in the middle position, the better the middle unloading capacity is.

[0047] In some embodiments, the main control valve is a positive opening equal four-edge spool valve;

[0048] The two shoulders are respectively a first shoulder 9 and a second shoulder 10;

[0049] When the main control valve is in the zero position, the four geometric negative overlap amounts formed by the first shoulder 9 and the second shoulder 10 and the distribution window A port 5 and the distribution window B port 7 in the axial direction are equal.

[0050] In some embodiments, a combined throttle groove is formed on the shoulder;

[0051] The combined throttling groove is a combination of a trapezoidal throttling groove and a rectangular throttling groove. The depth of the combined throttling groove remains unchanged at the maximum value in the trapezoidal throttling area, and the depth of the combined throttling groove increases linearly from the minimum value to the maximum value in the rectangular throttling area.

[0052] The structural feature of the main control valve in this embodiment is that its valve core 1 has a combined throttling groove 102 on the first convex shoulder 9 and the second convex shoulder 10. Compared with the single-stage throttling groove structure, the structure is relatively simple, and the relationship between its area gradient and the change of the valve opening is relatively simple, which cannot meet the requirements of eliminating steady-state fluid force and reducing the pressure of the left and right control chambers under complex working conditions. The throttling groove area gradient of the combined throttling groove changes with the valve opening to adapt to complex working conditions, reduce the pressure of the left and right control chambers, and improve the neutral unloading capacity of the main control valve. The valve core with a trapezoidal throttling groove 101 is as follows: Figure 3 As shown, the structure with combined throttling groove 102 is as follows Figure 4 As shown. Figure 3 and Figure 4 It can be seen that the four throttling grooves are evenly distributed in the circumferential direction of the first boss 9 and the second boss 10 close to the distribution window T-mouth 6, and the axial width and maximum radial depth of the throttling grooves are the same. The difference is that the combined throttling groove 102 is a combination of a trapezoidal throttling groove and a rectangular throttling groove, and its depth remains unchanged at the maximum value in the trapezoidal throttling area, while in the rectangular throttling area, the depth increases linearly from the minimum value to the maximum value, while the trapezoidal throttling groove 101 has only one trapezoidal throttling area, and the depth remains unchanged in the entire area.

[0053] The working principle of the controllable pitch propeller system is as follows: Figure 5 As shown in the figure, it includes a constant current source 201, a safety valve 202, a pressure gauge 203, a main control valve 204 and a load cylinder 205. A system simulation model including the main control valve components is built to compare the pressures of the left and right control chambers under different throttle groove configurations when the controllable pitch propeller system is in the stable pitch state after reversing and the main control valve is in the middle position. Figures 6-7 As shown. Figures 6-7 It can be seen that when the main control valve is in the middle position, the combined throttling groove can reduce the pressure of the left and right control chambers by 10%, and the pressure increases with the decrease of the opening amount (geometric negative overlap). When the opening amount is 0.3 mm, the pressure of the left and right control chambers can be reduced by 16%.

[0054] In the above embodiment, an indicator is introduced to evaluate the unloading capacity of the main control valve when it is in the middle position, and a combined throttling groove structure is proposed. The throttling groove area gradient changes with the valve opening to adapt to complex working conditions, which can improve the middle position unloading capacity of the main control valve.

[0055] The embodiments of the present application are described above with reference to the accompanying drawings, but the present application is not limited to the specific embodiments described above, and the specific embodiments described above are merely illustrative, but not restrictive, and a person of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims.

Claims

1. A main control valve for a controllable pitch propeller capable of improving the midship unloading capacity, characterized by, The utility model relates to a kind of main control valve, including: Valve core (1) and valve sleeve (2) of hollow structure; The valve core (1) is provided with two shoulders;Two the shoulder side of facing is opened with throttle groove, the valve core (1) is opened with through hole at the position close to each shoulder outside, and the through hole is used for high-pressure oil injection; The valve sleeve (2) is provided with flow distribution window A mouth (5), flow distribution window B mouth (7) and flow distribution window T mouth (6), the flow distribution window A mouth (5) and the flow distribution window B mouth (7) are control port, the flow distribution window A mouth (5) and the flow distribution window B mouth (7) are communicated with external oil circuit respectively, the flow distribution window T mouth (6) is communicated with intermediate oil circuit as oil return port; One shoulder and the flow distribution window A mouth (5) constitute the left control chamber of main control valve, and another shoulder and the flow distribution window B mouth (7) constitute the right control chamber of main control valve; Combined throttle groove is opened on the shoulder;The combined throttle groove is the combination of trapezoidal throttle groove and rectangular throttle groove, the depth of the combined throttle groove keeps maximum value unchanged in trapezoidal throttle area, and the depth of the combined throttle groove linearly increases from minimum value to maximum value in rectangular throttle area.

2. The main control valve for a pitch-controlled propeller with the ability to lift the midship unloading capacity according to claim 1, characterized in that, The main control valve is positive opening equal four-side spool valve; Two the shoulder is first shoulder (9) and second shoulder (10) respectively; When the main control valve is in zero position, the first shoulder (9) and the second shoulder (10) and the flow distribution window A mouth (5) and the flow distribution window B mouth (7) form four geometric negative overlap amounts in axial direction equal.

3. The main control valve for a pitch-controlled propeller with the ability to lift the midship unloading capacity according to claim 1, characterized in that, The performance of the main control valve is evaluated using mid-position unloading capacity; The mid-position unloading capacity is the pressure of the left control chamber and the right control chamber when the main control valve is in mid-position; The smaller the pressure value is, the smaller the mid-position unloading capacity is.

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