Hydraulic plunger pump and variable adjustment return mechanism thereof

Abstract

The hydraulic plunger pump comprises a swash plate, a steel ball arranged on the swash plate, an upper spring seat, a small return spring, a large return spring, a lower spring seat and a pump body, and is characterized in that the hydraulic plunger pump further comprises a base, one end of the base is fixedly installed in an installation groove of the pump body, and the other end of the base is provided with a first spherical surface; the lower spring seat is provided with a second spherical surface matched with the first spherical surface of the base, and the lower spring seat abuts against the first spherical surface of the base through the second spherical surface to form a first spherical pair. The upper spring seat is provided with a third spherical surface matched with the steel ball, and the upper spring seat abuts against the steel ball through the third spherical surface to form a second spherical pair. The upper spring seat is provided with a guide boss, the lower spring seat is provided with a guide hole matched with the guide boss, and the guide boss is matched with the guide hole to form a cylindrical pair. Automatic centering is achieved, eccentric wear is avoided, movement guiding is accurate, work is stable, reliability is high, the service life is long, the structure is ingenious, and implementation is easy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of accessory design of aircraft hydraulic systems, in particular, to a variable adjustment return mechanism for a swash plate type axial piston pump and a hydraulic piston pump comprising the mechanism. BACKGROUND

[0002] The variable adjustment return mechanism is one of the core components of the constant pressure variable swash plate type axial piston pump, and its performance directly determines the realization accuracy, response speed and working stability of the constant pressure variable function of the hydraulic pump, thereby indirectly controlling the output flow and pressure characteristics of the hydraulic pump. Therefore, the improvement of the reliability of the variable adjustment return mechanism is crucial to ensure the work of the entire hydraulic system.

[0003] In the prior art (as shown in the accompanying drawings of the specification Figure 4 ), the mechanism usually includes a swash plate, a steel ball, an upper spring seat, a return spring (large and small springs), a lower spring seat and a pump body. The working principle is: the swash plate swings under the drive of the variable piston, pushes the upper spring seat through the steel ball, and compresses the return spring to realize the feedback and reset of the variable.

[0004] However, the existing structure has obvious defects: there is an angle between the axis of the variable piston and the axis of the return mechanism, which causes the direction of the force of the steel ball on the upper spring seat to be inconsistent with the axis, and there is a lateral component. At the same time, the lower spring seat and the pump body mounting surface are in rigid plane contact, lacking self-adaptive adjustment capability. This makes the return spring not only subjected to axial force, but also continuously subjected to lateral force during compression and recovery. In addition, the spring end surface is not a complete plane, resulting in a small relative sliding and tilting between the spring end and the spring seat contact surface. Under the conditions of frequent variable of the hydraulic pump and aircraft vibration, this fretting wear will continue to intensify, eventually leading to wear and even failure of the return spring.

[0005] The wear of the return spring will change the stiffness characteristics of the spring, causing the pressure regulating pressure of the hydraulic pump to drift, the variable point to be misaligned, and the control accuracy to be reduced, which seriously threatens the reliability and safety of the aviation hydraulic pump and even the entire aircraft hydraulic system. SUMMARY

[0006] In view of the above shortcomings of the prior art, the present application aims to solve the problem of fretting wear of the return spring caused by poor centering and contact following between the parts in the variable adjustment return mechanism of the hydraulic pump. Thus, a variable adjustment return mechanism capable of automatic centering and avoiding eccentric wear is provided to improve the accuracy, stability and reliability of the variable control of the hydraulic pump.

[0007] The technical problem of the present application is solved by the following technical scheme: a variable regulating return mechanism for a hydraulic pump, comprising a swash plate, a steel ball arranged on the swash plate, an upper spring seat, a return small spring, a return large spring, a lower spring seat and a pump body, characterized in that: a base is further arranged, one end of the base is fixedly arranged in a mounting groove of the pump body, and the other end is provided with a first spherical surface.

[0008] The lower spring seat is provided with a second spherical surface matched with the first spherical surface of the base, and the lower spring seat is in abutment with the first spherical surface of the base through the second spherical surface, thereby forming a first spherical pair.

[0009] The upper spring seat is provided with a third spherical surface matched with the steel ball, and the upper spring seat is in abutment with the steel ball through the third spherical surface, thereby forming a second spherical pair.

[0010] The upper spring seat is provided with a guide boss, the lower spring seat is provided with a guide hole matched with the guide boss, and the guide boss and the guide hole are matched to form a cylindrical pair.

[0011] In the foregoing variable regulating return mechanism for a hydraulic pump, further, the lower spring seat is provided with a first inner step surface and a first outer step surface, the first inner step surface is in abutment with an end surface of the first return small spring, and the first outer step surface is in abutment with an end surface of the return large spring.

[0012] In the foregoing variable regulating return mechanism for a hydraulic pump, further, the upper spring seat is provided with a second inner step surface and a second outer step surface, the second inner step surface is in abutment with an end surface of the return small spring, and the second outer step surface is in abutment with an end surface of the return large spring.

[0013] In the foregoing variable regulating return mechanism for a hydraulic pump, further, the matching gap of the cylindrical pair is configured to allow the upper spring seat to move axially and rotate circumferentially relative to the lower spring seat, but limit the radial movement thereof.

[0014] In the foregoing variable regulating return mechanism for a hydraulic pump, further, the first spherical surface on the base is a convex spherical surface, and the second spherical surface on the lower spring seat is a concave spherical surface matched therewith.

[0015] Or the first spherical surface on the base is a concave spherical surface, and the second spherical surface on the lower spring seat is a convex spherical surface matched therewith.

[0016] In the foregoing variable regulating return mechanism for a hydraulic pump, further, the third spherical surface on the upper spring seat is a concave spherical surface for accommodating the steel ball.

[0017] In the variable regulating return mechanism for hydraulic pump as claimed in the preceding, further, the guide boss is a cylindrical boss, and the guide hole is a cylindrical hole matched with the guide boss.

[0018] In the variable regulating return mechanism for hydraulic pump as claimed in the preceding, further, the first spherical surface of the base and / or the second spherical surface of the lower spring seat are coated with a wear-resistant coating.

[0019] In the variable regulating return mechanism for hydraulic pump as claimed in the preceding, further, the first spherical surface pair and the second spherical surface pair are configured to allow the upper spring seat and the lower spring seat to produce adaptive deflection when the swash plate swings, so that the axes of the return small spring and the return big spring always keep consistent with the direction of the acting force.

[0020] A hydraulic piston pump comprising the variable regulating return mechanism as claimed above.

[0021] Compared with the prior art, the present application has the following beneficial effects: 1. Automatic centering and avoiding eccentric wear: By setting two spherical surface pairs between the upper and lower spring seats and the steel balls and the base, the mechanism is given the ability of adaptive adjustment in space with multiple degrees of freedom. When the swash plate swings and the direction of the acting force changes, the upper and lower spring seats can deflect in the spherical surface pairs, so that the axes of the return springs always keep consistent with the axial force, fundamentally eliminating the possibility of the springs bearing lateral force and avoiding the eccentric wear and fretting wear of the spring end face.

[0022] 2. Precise movement guidance and stable work: By setting a cylindrical pair (guide boss and guide hole) between the upper and lower spring seats, the radial movement is strictly limited while the axial movement and the circumferential rotation are allowed. This ensures that the upper and lower spring seats and the two return springs always maintain high coaxiality during the entire working process, the movement is smooth without jamming, and the accuracy and response speed of the variable control are improved.

[0023] 3. High reliability and long service life: The present application effectively solves the failure mode of return spring wear, significantly improves the service life and reliability of the variable regulating return mechanism, and thus improves the operation safety and reliability of the aviation hydraulic piston pump under complex working conditions and reduces the maintenance cost.

[0024] 4. Ingenious structure and easy to implement: The improved scheme only adds a base and changes the matching relationship on the basis of the existing structure, without complex modification of the main structure such as the pump body, and has good processability, easy engineering implementation and promotion. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structural schematic view of the variable regulating return mechanism of the present application.

[0026] Figure 2 is a schematic view of a lower spring seat structure of the present application.

[0027] Figure 3 is a schematic view of an upper spring seat structure of the present application.

[0028] Figure 4 is a schematic view of a variable adjustment return mechanism of the prior art.

[0029] Reference numerals in the drawing: 1 - swash plate, 2 - steel ball, 3 - upper spring seat, 4 - return small spring, 5 - return large spring, 6 - lower spring seat, 7 - pump body, 8 - base.

[0030] T - guide boss, K1 - guide hole, A1 - first inner side step surface, A2 - first outer side step surface, B1 - second inner side step surface, B2 - second outer side step surface. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be further specifically described below by way of examples in combination with the drawings.

[0032] The variable function assembly of the swash plate type axial piston pump mainly consists of a swash plate, a follow-up piston component, a return small spring, a return large spring, a spring seat and other parts. When there is a flow demand in the hydraulic system, the swash plate is always in the maximum inclination position under the elastic force of the return large and small springs, and the hydraulic pump provides high-pressure hydraulic energy to the system. When there is no large flow demand in the hydraulic system, the high-pressure oil introduced from the high-pressure outlet acts on the follow-up piston, the follow-up piston pushes the swash plate to change its inclination, and the flow size output by the hydraulic pump to the system is changed by adjusting the inclination of the swash plate. When the hydraulic pump switches from full flow to zero flow, the swash plate changes from large swing angle to nearly zero swing angle, and the two compression springs on the return mechanism are compressed to the shortest working state; when the hydraulic pump switches from zero flow to full flow, the swash plate changes from nearly zero swing angle to large swing angle, and the two compression springs on the return mechanism recover to the longest working state. According to the working needs, the above actions are repeatedly switched. In the above repeated switching process, if the contact followability between the parts is not good, it is easy to cause unstable movement and wear of the contact parts.

[0033] In view of this phenomenon, the present embodiment designs a variable adjustment return mechanism for a hydraulic pump, as shown in Figure 1 which comprises a swash plate 1, a steel ball 2 arranged on the swash plate 1, an upper spring seat 3, a return small spring 4, a return large spring 5, a lower spring seat 6 and a pump body 7.

[0034] The key lies in designing a base 8, one end of which is a flat surface, and the other end is provided with a first spherical surface, and the flat end is fixedly installed in the mounting groove of the pump body 7.

[0035] The lower spring seat 6 is provided with a second spherical surface matched with the first spherical surface of the base 8, as shown inFigure 2 The lower spring seat 6 is in abutment with the first spherical surface of the base 8 through the second spherical surface, forming a first spherical pair.

[0036] Further, the first spherical pair has two forms: the first spherical surface on the base 8 is a convex spherical surface, and the second spherical surface on the lower spring seat 6 is a concave spherical surface matched therewith. Alternatively, the first spherical surface on the base 8 is a concave spherical surface, and the second spherical surface on the lower spring seat 6 is a convex spherical surface matched therewith.

[0037] The upper spring seat 3 is provided with a third spherical surface matched with the steel ball 2, as shown in Figure 3 The upper spring seat 3 is in abutment with the steel ball 2 through the third spherical surface, forming a second spherical pair.

[0038] The third spherical surface on the upper spring seat 3 is a concave spherical surface, which is specially designed to accommodate the steel ball 2. When the swash plate 1 drives the steel ball 2 to rotate around the swash plate 1 trunnion, the steel ball 2 drives the upper spring seat 3 to rotate.

[0039] The upper spring seat 3 is provided with a guide boss T, and the lower spring seat 6 is provided with a guide hole K1 matched with the guide boss T. The guide boss T and the guide hole K1 form a cylindrical pair.

[0040] The lower spring seat 6 is provided with a first inner step surface A1 and a first outer step surface A2. The first inner step surface A1 is in abutment with the end surface of the small return spring 4, and the first outer step surface A2 is in abutment with the end surface of the large return spring 5.

[0041] Similarly, the upper spring seat 3 is provided with a second inner step surface B1 and a second outer step surface B2. The second inner step surface B1 is in abutment with the end surface of the small return spring 4, and the second outer step surface B2 is in abutment with the end surface of the large return spring 5.

[0042] The matching clearance of the cylindrical pair is configured to allow the upper spring seat 3 to move axially and rotate circumferentially relative to the lower spring seat 6, but limit its radial movement. Thus, lateral sliding of the two return springs with the upper and lower spring seats is avoided. Since the guide boss T of the upper spring seat 3 and the guide hole K1 of the lower spring seat 6 form a cylindrical pair, the lower spring seat 6 also rotates relative to the base 8 during the rotation of the swash plate 1, thereby ensuring that the end surfaces of the two return springs are in good contact with the matching surfaces of the upper and lower spring seats at all times.

[0043] Since the upper and lower spring seats are matched with the steel ball 2 and the base 8 through spherical pairs, they have good movement flexibility, good contact followability between parts, and avoid large deflection and sliding between parts caused by the variable or vibration of the hydraulic pump. Thus, the entire return mechanism is automatically centered in real time. Finally, the wear caused by the deflection and lateral movement of the spring end surface is avoided.

[0044] Furthermore, the first spherical surface of the base 8 and / or the second spherical surface of the lower spring seat 6 is coated with a wear-resistant coating. Of course, the first spherical surface of the base 8 and / or the second spherical surface of the lower spring seat 6 can also be subjected to a quenching process to improve its wear resistance.

[0045] The first spherical surface pair and the second spherical surface pair are configured to allow the upper spring seat 3 and the lower spring seat 6 to produce adaptive deflection when the swash plate 1 swings, so that the axes of the return small spring 4 and the return large spring 5 are always consistent with the direction of the acting force. The situation of excessively high pressure regulating pressure caused by the wear of the return small spring 4 is improved, the stability of the hydraulic pump is improved, and the safety and reliability of the hydraulic pump and even the hydraulic system are improved.

[0046] The present application is applied to a hydraulic piston pump and refers to the content comprising the above variable adjusting return mechanism. The use of the present application in an aeronautical hydraulic piston pump in an aircraft hydraulic system accessory can improve the reliability of the aircraft in flight.

[0047] The above embodiments are illustrative of the present application and are not limiting of the present application. The described embodiments are only a part of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

Claims

1. A variable regulating return mechanism for hydraulic pump, comprising swash plate (1), steel ball (2) arranged on the swash plate, upper spring seat (3), return small spring (4), return big spring (5), lower spring seat (6) and pump body (7), characterized in that: Further comprising a base (8), one end of which is fixedly installed in the mounting groove of the pump body, and the other end is provided with a first spherical surface; The lower spring seat is provided with a second spherical surface matched with the first spherical surface of the base, and the lower spring seat is in abutment with the first spherical surface of the base through the second spherical surface, forming a first spherical pair; The upper spring seat is provided with a third spherical surface matched with the steel ball, and the upper spring seat is in abutment with the steel ball through the third spherical surface, forming a second spherical pair; The upper spring seat is provided with a guide boss (T), and the lower spring seat is provided with a guide hole (K1) matched with the guide boss, and the guide boss and the guide hole form a cylindrical pair.

2. A variable displacement return mechanism for a hydraulic pump as set forth in claim 1, wherein, The lower spring seat (6) is provided with a first inner step surface (A1) and a first outer step surface (A2), the first inner step surface is in abutment with the end surface of the small return spring (4), and the first outer step surface is in abutment with the end surface of the large return spring (5).

3. A variable displacement return mechanism for a hydraulic pump as set forth in claim 1, wherein The upper spring seat (3) is provided with a second inner step surface (B1) and a second outer step surface (B2), the second inner step surface is in abutment with the end surface of the small return spring (4), and the second outer step surface is in abutment with the end surface of the large return spring (5).

4. A variable displacement return mechanism for a hydraulic pump as set forth in claim 1, wherein The matching gap of the cylindrical pair is configured to allow the upper spring seat (3) to move axially and rotate circumferentially relative to the lower spring seat (6), but limit its radial movement.

5. A variable displacement return mechanism for a hydraulic pump as set forth in claim 1, wherein, The first spherical surface on the base (8) is a convex spherical surface, and the second spherical surface on the lower spring seat (6) is a concave spherical surface matched therewith; Or the first spherical surface on the base (8) is a concave spherical surface, and the second spherical surface on the lower spring seat (6) is a convex spherical surface matched therewith.

6. A variable displacement return mechanism for a hydraulic pump as set forth in claim 1, wherein The third spherical surface on the upper spring seat (3) is a concave spherical surface for accommodating the steel ball (2).

7. A variable displacement return mechanism for a hydraulic pump as set forth in claim 1, wherein The guide boss (T) is a cylindrical boss, and the guide hole (K1) is a cylindrical hole matched therewith.

8. A variable displacement return mechanism for a hydraulic pump as set forth in claim 1, wherein The first spherical surface of the base (8) and / or the second spherical surface of the lower spring seat (6) is coated with a wear-resistant coating.

9. A variable displacement return mechanism for a hydraulic pump as set forth in claim 1, wherein, The first spherical pair and the second spherical pair are configured to allow the upper spring seat (3) and the lower spring seat (6) to produce adaptive deflection when the swash plate (1) swings, so that the axes of the small return spring (4) and the large return spring (5) are always consistent with the direction of the acting force.

10. A hydraulic piston pump characterized by A variable adjustment return mechanism as claimed in any one of claims 1 to 9. A variable adjustment return mechanism as claimed in any one of claims 1 to 9.

Images