CN112780623A

CN112780623A - Overflow valve suitable for there is back pressure operating mode compensation hydraulic power

Info

Publication number: CN112780623A
Application number: CN202011561664.7A
Authority: CN
Inventors: 杨庆俊; 李丛飞; 毛奇; 罗宁波; 刘钰栋; 姜宏暄; 罗小梅; 吕庆军
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2020-12-25
Filing date: 2020-12-25
Publication date: 2021-05-11
Anticipated expiration: 2040-12-25
Also published as: CN112780623B

Abstract

An overflow valve suitable for compensating hydraulic power under a backpressure working condition belongs to the technical field of aerospace servo systems. The valve body is provided with an inlet A, an outlet B, an overflow port C and an oil discharge port D, a cavity e, an oil cavity f and a spring cavity g are formed between the valve body and the valve core, the overflow port C is communicated with the oil cavity f, the valve core and the valve body are provided with a valve port at the inlet end of the oil cavity f, and a flange structure is arranged at the position of the valve core close to the valve port. The valve core adopts a stepped design, a hollow design, a parallel double-spring design and the like, so that the valve has a compact structure and a large thrust-weight ratio. By arranging the damping hole on the valve core, oil is supplemented in time in the retraction process of the valve core, and the phenomenon of 'jamming' of the valve core is effectively eliminated. By reasonably matching the throttling areas of the valve core damping hole and the oil return port damping hole, the adverse effect of the back pressure of the overflow port on the balance of the valve core is effectively eliminated.

Description

Overflow valve suitable for there is back pressure operating mode compensation hydraulic power

Technical Field

The invention belongs to the technical field of aerospace servo systems, and particularly relates to an overflow valve suitable for compensating hydrodynamic force under a backpressure working condition.

Background

The overflow valve is used as a pressure control element of a servo energy source, mainly has the functions of constant pressure and overflow, and can also play the roles of overload prevention and safety protection when being used as a safety valve. Compared with a common hydraulic system, the aerospace servo system has the characteristics of high pressure and large flow, and provides higher requirements for the reliability, the pressure stabilizing precision and the thrust-weight ratio of the overflow valve. Particularly, a constant pressure spring and a valve core assembly of the overflow valve for the aerospace system have a large thrust-weight ratio, and hydraulic fluctuation of a valve port is small as much as possible in the opening and closing process. In addition, the overflow valve for the aerospace system has good dynamic performance, still has good pressure stabilizing precision under the condition of back pressure, and the valve core still can stably stretch out and draw back under the action of large inertia load and is not blocked.

The common overflow valve usually adopts a single spiral compression spring as a pressure regulating spring of the valve, and when the thrust of the spring is improved, the spring is usually large in size, and faults such as jamming, fatigue and fracture are easy to occur, so that potential safety hazards are brought to the operation of a system. When designing an overflow valve for a space system, the reliability of the structure should be fully considered. Conventional relief valves, on the other hand, typically do not have effective means for suppressing steady-state hydrodynamic forces. In addition, in the use occasion of ordinary overflow valve, the overflow generally flows back to the oil tank, and the backpressure of overflow chamber is not big, and sometimes has to face the operating mode of high backpressure in the aerospace power system. Finally, under the working condition of sudden load drop of the common overflow valve, the large-thrust spring pushes the valve core to reset, and the valve core is often stuck due to the vacuum, which is also not allowed in an aerospace servo system. Although the above problems can be alleviated simply by improving the machining accuracy and selecting a material with superior performance, the cost is high, and the patent aims to alleviate the above problems from the viewpoint of optimizing the structural design.

Disclosure of Invention

In order to solve the problems existing in the prior art, the invention provides an overflow valve which is suitable for compensating hydraulic power under the working condition with back pressure.

The technical scheme adopted by the invention is as follows: an overflow valve suitable for compensating hydrodynamic force under the working condition of back pressure comprises a valve core, a valve body, a spring end cover and a main spring, wherein the valve body is in sliding fit with the valve core and sleeved outside the valve core; the valve body is provided with an inlet A, an outlet B, an overflow port C and an oil discharge port D, a cavity e, an oil cavity f and a spring cavity g are formed between the valve body and the valve core, the overflow port C is communicated with the oil cavity f, the valve core and the valve body are provided with a valve port at the inlet end of the oil cavity f, and a flange structure is arranged at the position of the valve core close to the valve port.

The invention has the beneficial effects that:

1. the invention improves the structure of the traditional slide valve type overflow valve. The valve core flange designed based on valve port flow field calculation fluid dynamics iteration optimization effectively compensates steady-state hydrodynamic force, and makes the pressure close when the valve core is opened and closed.

2. The valve core adopts a step design, a hollow design, a parallel double-spring design and the like, so that the structure of the valve is compact and the valve has a large thrust-weight ratio.

3. By arranging the damping hole on the valve core, oil is supplemented in time in the retraction process of the valve core, and the phenomenon of 'jamming' of the valve core is effectively eliminated. On the other hand, by reasonably matching the throttling areas of the valve core damping hole and the oil return port damping hole, the adverse effect of the back pressure of the overflow port on the balance of the valve core is effectively eliminated, so that the invention can be well suitable for the working condition that the overflow port has back pressure.

4. The designed overflow valve which utilizes the flange structure to compensate hydraulic power and utilizes the active damping hole to eliminate back pressure has the characteristics of high pressure stabilizing precision and quick response, meets the technical requirements of an aerospace servo system, and improves the reliability of equipment.

Drawings

FIG. 1 is a front cross-sectional view of the present invention;

FIG. 2 is an enlarged view of a portion K-1 of FIG. 1;

FIG. 3 is an enlarged view of a portion K-2 of FIG. 1;

FIG. 4 is an isometric view of the valve cartridge;

FIG. 5 is a front view of the valve cartridge;

FIG. 6 is a schematic view of a constant pressure flooding condition of the present invention;

wherein: 1. a spring end cap; 2. a spring guide rod; 3. a spring washer; 4. a main spring; 5. plugging by screwing; 6. an oil chamber f; 7. an auxiliary spring; 8. a valve core; 9. a valve body; 10. an outlet B; 11. an inlet A; 12. a flange structure; 13. a first damping hole; 14. an overflow port C; 15. a spring cavity g; 16. an oil discharge port D; 17. a second damping hole; 18. a chamber e; 19. an end face i; 20. a small groove; 21. the annular surface j.

Detailed Description

In order to make the technical personnel in the technical field better understand the scheme of the invention, the invention is further described in detail with reference to the attached drawings 1-6.

An overflow valve suitable for compensating hydrodynamic force under the working condition of back pressure comprises a valve core 8, a valve body 9 which is in sliding fit with the valve core 8 and sleeved outside the valve core 8, a spring end cover 1 which is plugged at one side of the valve body 9, and a main spring 4 which is arranged between the spring end cover 1 and the valve core 8; an inlet A11, an outlet B10, an overflow port C14 and an oil discharge port D16 for connecting an oil tank are arranged on the valve body 9, a chamber e18, an oil chamber f6 and a spring chamber g15 are formed between the valve body 9 and the valve core 8, the overflow port C14 is communicated with the oil chamber f6, a valve port is formed in the inlet end of the oil chamber f6 of the valve core 8 and the valve body 9, the auxiliary spring 7 is coaxially arranged on the inner side of the main spring 4, and two ends of the auxiliary spring 7 are respectively abutted between the spring end cover 1 and the valve core 8.

Also, mainspring 4 and auxiliary spring 7 suit are on

spring guide

2, and 2 rear ends of spring guide are contradicted in

spring end cover

1, and 2 front ends of spring guide insert in the slot that case 8 was equipped with, and spring guide 2 is three-step structure and increases from the front to the back diameter in proper order, mainspring 4 is contradicted on the biggest step face of spring guide 2, and auxiliary spring 7 is contradicted on the second step face of spring guide 2.

Spring washers 3 are arranged between the main spring 4 and the spring guide rod 2 and between the auxiliary spring 7 and the spring guide rod.

The overflow valve is connected to a loop needing protection or needing constant pressure and overflow. A plurality of small grooves 20, preferably four small grooves 20 are formed in the end face i19 of the valve core 8, as shown in the part diagrams of the valve core 8 in FIGS. 4 to 5, circuit oil firstly enters a chamber e18 formed by the end face i19 and a hole passage of the valve body 9 and acts on the end face i19 to form hydraulic thrust. When the hydraulic thrust is smaller than the spring force of the main spring 4 and the auxiliary spring 7, the valve core 8 works at the right position, the valve port is closed, external oil flows in from the inlet A11 and flows out from the outlet B10, no overflow exists, and the oil pressure at the inlet and the outlet is not changed. At this time, the position of the valve core 8 and the opening and closing of the valve port are shown in fig. 1. When the hydraulic thrust is greater than the spring force, the valve core 8 moves leftwards, the valve port is gradually opened, external oil enters the overflow port C14 through the valve port, and the designed overflow valve overflows and releases the pressure of the incoming oil. The opening degree of the valve port changes with the change of the hydraulic pressure, and the hydraulic pressure flowing out of the outlet B10 is maintained at a constant value. At this time, the position of the valve core 8 and the opening and closing of the valve port are shown in fig. 6.

In order to solve some problems possibly encountered in the practical use process in the aerospace servo field, as described in the background art, the invention mainly makes the following three aspects of structural design.

Firstly, a flange structure 12 is arranged at the position, close to the valve port, of the valve core 8, as shown in fig. 1, 3 and 6, and is used for weakening steady-state hydraulic power when the valve port is opened and closed. The steady state hydrodynamic force is generated by the change of momentum of oil passing through the valve port, and the essential reason is that the flow field pressure of the valve port is lower than the static pressure when the valve port is closed. By optimizing the diameter Dt of the flange structure 12 and the distance Lt between the right surface of the flange structure 12 and the inner wall of the valve body 9, the pressure and flow field distribution at the valve port can be changed, so that the pressure of the end surface of the valve core 8 approaches the static pressure when the valve core is closed when the valve core is opened, most of the hydrodynamic force is compensated, and the pressure stabilizing precision of the valve is ensured. The flange structure 12 of the valve core 8 generally has no versatility, and valves with different structural sizes have different flange structures 12 with different sizes in different occasions, but the design method of the flange structure 12 has certain versatility. Conventional flange structures 12 are dimensioned using experience-based trial and error methods, which are not only laborious and not accurate enough, but also overcompensating. The iterative optimization based on valve port flow field computational fluid dynamics simulation is adopted, the size of the flange structure 12 is optimally designed, the optimization target is that the hydraulic fluctuation covering the whole stroke of the valve core 8 is minimum, and the optimal flange structure 12 covering the whole stroke of the valve core 8 is obtained.

And secondly, a bush of the valve core 8 is eliminated, and the diameter of a shoulder of the valve core 8 is designed in a stepped mode. After the partial introduction of the flange structure 12, the diameter of the bore of the valve body 9 must be correspondingly enlarged for assembly. The common overflow valve usually adopts a mode of installing a bush outside the valve core 8 to ensure the matching of the hole wall of the valve body and the valve core. When the requirement on the constant pressure performance of the overflow valve is high, the design has high requirement on the concentricity of a valve body pore passage, a valve core and a lining, the machining precision is high, and the structural reliability is insufficient under the working condition of large load. The overflow valve has the advantages that the diameter of the shoulder of the valve core 8 is designed in a stepped manner, the diameter of the shoulder of the valve core 8 matched with the enlarged part of the hole channel of the valve body 9 is synchronously increased, the processing difficulty is reduced, and the structural reliability is enhanced. In addition, in order to improve the thrust-weight ratio of the valve, a parallel double-spring design is adopted, the volume of the spring is reduced as much as possible while the thrust is increased, and the valve core 8 is designed to be hollow, so that the weight of the valve core is reduced as much as possible.

Thirdly, a first damping hole 13 is formed in the position, between the valve core 8 and the overflow port C14, of the valve core 8, the oil discharge port D16 of the valve core 8 in the spring cavity g15 is blocked by the plug 5, and a second damping hole 17 is formed in the plug 5 to form a pair of damping holes connected in series, namely the first damping hole 13 and the second damping hole 17 marked in the figures 1 and 6. In the overflow valve, the problem of 'stuck' of the valve core 8 caused by sudden load drop under a large-load working condition is solved by using the back pressure at the overflow port C14 and the first damping hole 13 and the second damping hole 17, and the influence of the back pressure on the acting force balance of the valve core 8 is eliminated by matching the throttling areas of the first damping hole 13 and the second damping hole 17. The principle is as follows:

when the working load suddenly drops, the hydraulic pressure acting on the end face i19 of the valve core 8 is not enough to overcome the spring forces of the main spring 4 and the auxiliary spring 7, the valve core 8 moves to the right, the volume of the spring cavity g15 is continuously enlarged, at the moment, oil needs to be supplemented to the spring cavity g15, otherwise the valve core 8 stops moving due to vacuum generated in the spring cavity g15, a stop-and-go moving state is presented, and the situation is more serious the faster the load pressure drops. According to the overflow valve, the damping hole I13 is formed in the position, between the spring cavity g15 and the overflow port C14, of the valve core 8, oil is supplemented to the spring cavity g15 through the back pressure at the overflow port C14, and the phenomenon that the valve core 8 is blocked is effectively eliminated.

On the other hand, since the land of the valve element 8 is designed in a stepped manner, the oil pressure of the oil chamber f6 acts on the annular surface j21, and the balance of the acting force on the valve element 8 is broken. Therefore, the overflow valve is provided with a second damping hole 17 on the plug 5 arranged at the oil discharge port D16, and oil of the overflow port C14 enters the spring cavity g15 through the first damping hole 13 and returns to the oil tank through the second damping hole 17. The first damping hole 13 and the second damping hole 17 are connected in series, wherein the oil pressure of the overflow port C14 is Pc, the oil tank pressure is 0, and the pressure Pg of the spring cavity g15 is related to the throttle areas A1 and A2 of the first damping hole 13 and the second damping hole 17. The calculation formula is as follows:

p is enabled to be achieved by reasonably designing the throttle areas A1 and A2 of the first damping hole 13 and the second damping hole 17_c·A_{Ring (C)}＝P_g·A_gThe influence of the back pressure on the balance of the valve core 8 can be eliminated, wherein A_{Ring (C)}The area of the annular surface j21 of the valve core 8, and Ag is the acting area of the oil liquid in the spring cavity g15 on the valve core 8.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides an overflow valve suitable for there is back pressure operating mode compensation hydraulic power which characterized in that: the valve comprises a valve core (8), a valve body (9) which is matched with the valve core (8) in a sliding way and is sleeved on the outer side of the valve core (8), a spring end cover (1) which is blocked on one side of the valve body (9) and a main spring (4) which is arranged between the spring end cover (1) and the valve core (8); the oil-saving valve is characterized in that an inlet A (11), an outlet B (10), an overflow port C (14) and an oil discharge port D (16) are arranged on the valve body (9), a cavity e (18), an oil cavity f (6) and a spring cavity g (15) are formed between the valve body (9) and the valve core (8), the overflow port C (14) is communicated with the oil cavity f (6), a valve port is formed in the inlet end of the oil cavity f (6) of the valve core (8) and the valve body (9), and a flange structure (12) is arranged at the position, close to the valve port, of the valve core (8).

2. The overflow valve suitable for the hydraulic power with back pressure working condition compensation of claim 1, wherein: the shoulder of the valve core (8) adopts a stepped structure.

3. The overflow valve suitable for the hydraulic power with back pressure working condition compensation of claim 1, wherein: the valve core (8) has a hollow structure.

4. The overflow valve suitable for the hydraulic power with back pressure working condition compensation of claim 1, wherein: the overflow valve suitable for the compensation hydraulic power under the back pressure working condition further comprises an auxiliary spring (7), the auxiliary spring (7) is coaxially arranged on the inner side of the main spring (4), and two ends of the auxiliary spring (7) are respectively abutted between the spring end cover (1) and the valve core (8).

5. The overflow valve suitable for the hydraulic power with back pressure working condition compensation of claim 4, wherein: the overflow valve suitable for having backpressure operating mode compensation hydrodynamic force still includes spring guide (2), conflict in spring end cover (1) spring guide (2) rear end, in spring guide (2) front end inserts the slot that case (8) were equipped with, spring guide (2) are three-step structure and increase in proper order from the front to the back diameter, main spring (4) are contradicted on the biggest step face of spring guide (2), and auxiliary spring (7) are contradicted on the second step face of spring guide (2).

6. The overflow valve suitable for the hydraulic power with back pressure working condition compensation of claim 5, wherein: spring gaskets (3) are arranged between the main spring (4), the auxiliary spring (7) and the spring guide rod (2).

7. The overflow valve suitable for the hydraulic power with back pressure working condition compensation of claim 1, wherein: a first damping hole (13) is formed in the position, between the valve core (8) and the overflow port C (14), of the valve core, a second damping hole (17) is formed in the position, between the valve core (8) and the spring cavity g (15), of the valve core, and the first damping hole (13) and the second damping hole (17) are connected in series.

8. The overflow valve suitable for the hydraulic power with back pressure working condition compensation of claim 7, wherein: an oil discharge port D (16) of the valve core (8) arranged at the spring cavity g (15) is plugged by a plug (5), and a second damping hole (17) is formed in the plug (5).

9. The overflow valve suitable for the hydraulic power with back pressure working condition compensation of claim 1, wherein: and a plurality of small grooves (20) are formed in the end face i (19) of the valve core (8), and a cavity e (18) is formed by the end face i (19) of the valve core (8) and the pore passage of the valve body (9) in an enclosing manner.