Main control valve for controllable-pitch propeller capable of improving neutral-position unloading capacity

Abstract

The invention discloses a main control valve capable of improving the neutral-position unloading capacity and used for a controllable-pitch propeller, and belongs to the technical field of hydraulic slide valves. The valve core is provided with two convex shoulders; throttling grooves are formed in the opposite sides of the two protruding shoulders, through holes are formed in the positions, close to the outer sides of the protruding shoulders, of the valve element, and the through holes are used for injecting high-pressure oil. The valve sleeve is provided with a flow distribution window port A, a flow distribution window port B and a flow distribution window port T, the flow distribution window port A and the flow distribution window port B are control ports and are respectively communicated with an external oil way, and the flow distribution window port T is an oil return port and is communicated with a middle oil way; one convex shoulder and the port A of the flow distribution window form a left control cavity of the main control valve, and the other convex shoulder and the port B of the flow distribution window form a right control cavity of the main control valve. According to the structure, the area gradient of the throttling groove can adapt to complex working conditions along with the change rule of the opening degree of the valve port, the pressure of the left and right control cavities is reduced when the main control valve is in the middle position, and then the middle-position unloading capacity of the main control valve can be improved.

Description

Technical Field

[0001] The present application belongs to the technical field of hydraulic sliding valves, and specifically relates to a main control valve for a pitch control propeller capable of improving the mid-position unloading capacity. Background Art

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

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

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

[0005] The main control valve for the adjustable pitch propeller is a positive opening four-sided sliding valve, that is, when it is in the zero position, the spool shoulder and the valve sleeve distribution window form four geometric negative overlaps of equal axial size. When the adjustable pitch propeller system receives a variable pitch command, according to the change in the relative movement of the spool and the valve sleeve, the working position of the main control valve can be divided into left position, right position and middle position, and its working position corresponds to the working state of the adjustable pitch propeller system: when the main control valve is in the left position, the adjustable pitch propeller system is in the forward state; when the main control valve is in the right position, the adjustable pitch propeller system is in the reverse state; when the main control valve is in the middle position, the adjustable pitch propeller system is in the stable pitch state. During the navigation of the ship, the adjustable pitch propeller system should not be frequently forward and reversed. Usually, one working condition corresponds to one pitch. Therefore, the adjustable pitch propeller system is in the stable pitch state in most cases, that is, the main control valve is in the middle position. At this time, the oil fills the external oil circuit, and the pressure of the two external oil circuits is approximately equal to the pressure of the left and right control chambers of the main control valve. If the pressure is too high, it will cause a series of failure behaviors such as the rupture of the external oil pipe.

[0006] The main control valve is a throttle groove slide valve, and its valve core has a throttle groove on the valve core shoulder. The throttle grooves of different shapes have different functional relationships between the flow area and the relative displacement of the valve core and valve sleeve, that is, the relationship between the area gradient and the valve port opening is different, which will cause the flow rate and flow velocity of the valve port to change. The throttle groove slide valve has the advantages of a large valve port hydraulic radius, good adjustment performance, easy to control area gradient, and not easy to be blocked. Because the structural dimensions of the throttle groove are very small, changes in the key structural dimension parameters of the throttle groove will affect the entire hydraulic system. At the same time, the valve core of the slide valve will be subjected to various types of forces during operation, such as: hydraulic pressure, hydraulic force, hydraulic lateral force and friction. The hydraulic force is generated because when the liquid flows through the throttle groove valve port, the flow direction and flow velocity change, resulting in a change in the momentum of the liquid, so that the valve core is subjected to an additional force, and the direction of the force is in the direction of closing the valve port. Due 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 pressure of the left and right control chambers when the slide valve is in the middle position. Common throttling groove slide valves generally have an annular groove with a rectangular cross-section on the valve core, which effectively eliminates the steady-state fluid force and thereby reduces the pressure in the left and right control chambers of the slide valve.

[0007] The structure of a single-stage throttling groove is relatively simple, and the relationship between its area gradient and the valve opening is relatively simple. For example, the area gradient of a rectangular throttling groove does not change with the valve opening, the area gradient of a triangular throttling groove is linearly related to the valve opening, and the area gradient of a trapezoidal throttling groove is a simple quadratic function relationship with the valve opening. For hydraulic systems with relatively simple movements, the single change rule of the area gradient can meet the requirements of eliminating steady-state fluid power and reducing the pressure of the left and right control chambers. However, for complex hydraulic systems such as the adjustable pitch propeller system, a single-stage throttling groove cannot well meet the requirements of eliminating steady-state fluid power and reducing the pressure of the left and right control chambers. Therefore, a new type of combined throttling groove is designed to make the throttling groove area gradient change rule with the valve opening to adapt to complex working conditions. Reducing the pressure of the left and right control chambers is one of the problems that technical personnel in the field urgently need to solve. Summary of the invention

[0008] The purpose of the present application is to provide a main control valve for a pitch control propeller that can improve the mid-position unloading capacity to adapt to complex working conditions and reduce the pressure in the left and right control chambers when the main control valve is in the mid-position.

[0009] According to a first aspect of an embodiment of the present application, a main control valve for a controllable pitch propeller capable of improving a neutral unloading capacity is provided, the main control valve comprising: a valve core and a valve sleeve of a hollow structure;

[0010] The valve core is provided with two convex shoulders; a throttling groove is provided on the opposite side of the two convex shoulders, and a through hole is provided on the valve core near 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 distribution window A port, a distribution window B port and a distribution window T port. The distribution window A port and the distribution window B port are control ports, the distribution window A port and the distribution window B port are respectively connected to the external oil circuit, and the distribution window T port is an oil return port connected to the intermediate oil circuit;

[0012] One convex shoulder and the distribution window A port constitute the left control chamber of the main control valve, and the other convex shoulder and the distribution window B port constitute the right control chamber of the main control valve.

[0013] In some optional embodiments of the present application, the main control valve is a positive opening equal four-side slide valve;

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

[0015] When the main control valve is at zero position, four geometric negative overlaps formed in the axial direction by the first convex shoulder, the second convex shoulder, the distribution window A port and the distribution window B port are equal.

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

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

[0018] The smaller the pressure value, the smaller the median unloading capacity.

[0019] In some optional embodiments of the present application, a combined throttling groove is provided on the boss;

[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 at a maximum value in the trapezoidal throttling area, and the depth of the combined throttling groove increases linearly from a minimum value to a maximum value in the rectangular throttling area.

[0021] The above technical solution of the present application has the following beneficial technical effects:

[0022] The main control valve structure of the embodiment of the present application can make the throttling groove area gradient change with the valve opening to adapt to complex working conditions, reduce the pressure in the left and right control chambers when the main control valve is in the middle position, and thereby improve the middle position unloading capacity of the main control valve. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0024] Figure 2 is a schematic diagram of a main control valve in a neutral position in an exemplary embodiment of the present application;

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

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

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

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

[0030] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with specific implementations and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concepts of the present application.

[0031] The accompanying drawings show schematic diagrams of layer structures according to embodiments of the present application. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clarity. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0032] Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are 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" and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0035] In the following, in combination with the accompanying drawings, a main control valve for a pitch control propeller that can improve the mid-position unloading capacity provided in an embodiment of the present application is described in detail through specific embodiments and application scenarios.

[0036] In a first aspect of an embodiment of the present application, a main control valve for a controllable pitch propeller capable of improving a neutral unloading capacity is provided, the main control valve comprising: a valve core 1 and a valve sleeve 2 of a hollow structure;

[0037] The valve core is provided with two convex shoulders; a throttling groove is provided on the opposite side of the two convex shoulders, and a through hole is provided on the valve core near the outer side of each convex shoulder, and the through hole is used for high-pressure oil injection;

[0038] The valve sleeve is provided with a distribution window A port 5, a distribution window B port 7 and a distribution window T port 6. The distribution window A port 5 and the distribution window B port 76 are control ports. The distribution window A port 5 and the distribution window B port 7 are respectively connected to the external oil circuit. The distribution window T port 6 is an oil return port connected to the intermediate oil circuit.

[0039] One convex shoulder and the distribution window A port 5 constitute the left control chamber of the main control valve, and the other convex shoulder and the distribution window B port 7 constitute the right control chamber of the main control valve.

[0040] Specifically, Figure 1 As shown, the main control valve for the adjustable pitch propeller is a positive opening four-side sliding valve, that is, when it is in the zero position, the boss and the valve sleeve 2 distribution window form four geometric negative overlaps with equal axial dimensions. The inner side of the two bosses of the valve core 1 has four throttling grooves in the circumferential direction, and its inner circumferential position is close to the outer side of the boss. There are two through holes, which can be regarded as P port 8, for high-pressure oil injection. The valve sleeve 2 is processed with three distribution windows, namely, the distribution window A port 5, the distribution window B port 7, and the distribution window T port 6. The distribution window A5 and the distribution window B port 7 are control ports that are connected to the first external oil circuit 3 and the second external oil circuit 4 respectively.

[0041] The main control valve structure for the adjustable pitch propeller in this embodiment can make the throttle groove area gradient change with the valve opening to adapt to complex working conditions, reduce the pressure in the left and right control chambers when the main control valve is in the middle position, and thus improve the middle position unloading capacity of the main control valve.

[0042] Principle Figure 2As shown in the figure, when the adjustable pitch propeller system receives a variable pitch instruction, according to the change of the relative movement of the valve core 1 and the valve sleeve 2, the working position of the main control valve can be divided into the left position, the right position and the middle position: when the valve core 1 moves to the right relative to the valve sleeve 2, the flow area from the P port 8 to the distribution window A port 5 becomes larger, and the flow area from the P port 8 to the distribution window B port 7 becomes smaller, and the high-pressure oil mainly flows to the left control chamber, and then flows to the load hydraulic cylinder through the first external oil circuit 3. At this time, the main control valve is in the left position; when the valve core 1 moves to the left relative to the valve sleeve 2, The flow area from P port 8 to distribution window B port 7 becomes larger, and the flow area from P port 8 to distribution window A port 5 becomes smaller. The high-pressure oil mainly flows to the right control chamber, and then flows to the load hydraulic cylinder through the second external oil circuit 4; when the relative position of the valve core 1 with respect to the valve sleeve 2 does not change, the flow area from P port 8 to distribution window A port 5 and distribution window B port 7 basically does not change. After flowing to the left and right control chambers, the high-pressure oil flows to the distribution window T port 6 through the boss throttling groove, and flows back to the oil tank through the middle oil circuit. 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 using the mid-position unloading capacity;

[0044] The mid-position unloading capacity is the pressure in the left and right control chambers when the main control valve is in the mid-position;

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

[0046] The main control valve is in the middle position, and the corresponding adjustable pitch propeller system is in a stable pitch state. At this time, the flow area from the P port 8 to the distribution window A port 5 and the distribution window B port 7 basically does not change, and the oil fills the first external oil circuit 3 and the second external oil circuit 4. At this time, the pressures of the two external oil circuits, the first external oil circuit 3 and the second external oil circuit 4, are approximately equal to the pressures of the left and right control chambers of the main control valve, namely PA and PB. If the pressure is too high, it will cause a series of failure behaviors such as the rupture of the first external oil circuit 3 and the second external oil circuit 4. For this reason, the middle position unloading capacity index is introduced in the performance evaluation of the main control valve, that is, when the main control valve is in the middle position, the pressures PA and PB of the left and right control chambers are small: when the main control valve is in the middle position, the pressures PA and PB of the left and right control chambers are small, and the middle position unloading capacity is good.

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

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

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

[0050] In some embodiments, a combined throttling groove is provided on the boss;

[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 a maximum value in the trapezoidal throttling area, and the depth of the combined throttling groove increases linearly from a minimum value to a maximum value in the rectangular throttling area.

[0052] The structural feature of the main control valve in this embodiment is that the 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 valve opening is relatively simple, which cannot meet the requirements of eliminating steady-state fluid power 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 mid-position 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 shoulder 9 and the second shoulder 10 close to the distribution window T-mouth 6, and the axial width and the maximum radial depth of the throttling groove 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 FIG. 1 , a system simulation model including a constant current source 201, a safety valve 202, a pressure gauge 203, a main control valve 204 and a load cylinder 205 is constructed to compare the pressures of the left and right control chambers under different throttle groove configurations when the pitch control propeller system is in a stable pitch state after reversing and the main control valve is in the middle position. Figure 6-7 As shown. Figure 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 it increases with the decrease of the opening amount (geometric negative overlap). When the opening amount is 0.3mm, 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 in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A main control valve for a pitch control propeller capable of improving the mid-position unloading capacity, characterized in that: include: A valve core (1) and a valve sleeve (2) with a hollow structure; The valve core (1) is provided with two bosses; a throttling groove is provided on the opposite sides of the two bosses; the valve core (1) is provided with a through hole near the outer side of each boss, and the through hole is used for high-pressure oil injection; The valve sleeve (2) is provided with a distribution window A port (5), a distribution window B port (7) and a distribution window T port (6); the distribution window A port (5) and the distribution window B port (7) are control ports; the distribution window A port (5) and the distribution window B port (7) are respectively connected to an external oil circuit; the distribution window T port (6) is an oil return port connected to an intermediate oil circuit; One convex shoulder and the flow distribution window A port (5) form a left control chamber of the main control valve, and the other convex shoulder and the flow distribution window B port (7) form a right control chamber of the main control valve.

2. The main control valve for a controllable pitch propeller capable of improving the mid-position unloading capacity according to claim 1, characterized in that: The main control valve is a positive opening equal four-sided slide valve; The two shoulders are respectively a first shoulder (9) and a second shoulder (10); When the main control valve is at zero position, the four geometric negative overlaps formed in the axial direction by the first convex shoulder (9) and the second convex shoulder (10) and the distribution window A port (5) and the distribution window B port (7) are equal.

3. The main control valve for a controllable pitch propeller capable of improving the mid-position unloading capacity according to claim 1, characterized in that: The performance of the main control valve is evaluated by the mid-position unloading capacity; The neutral unloading capacity is the pressure of the left control chamber and the right control chamber when the main control valve is in the neutral position; The smaller the pressure value, the smaller the median unloading capacity.

4. The main control valve for a controllable pitch propeller capable of improving the mid-position unloading capacity according to claim 1, characterized in that: A combined throttling groove is provided on the boss; 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 a maximum value in the trapezoidal throttling area, and the depth of the combined throttling groove increases linearly from a minimum value to a maximum value in the rectangular throttling area.

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