CN116857147A

CN116857147A - Plunger type hydraulic pump and hydraulic system

Info

Publication number: CN116857147A
Application number: CN202310912146.2A
Authority: CN
Inventors: 蓝维玲
Original assignee: Foshan Leisha Model Technology Co ltd
Current assignee: Foshan Leisha Model Technology Co ltd
Priority date: 2023-07-24
Filing date: 2023-07-24
Publication date: 2023-10-10

Abstract

The application provides a plunger type hydraulic pump and a hydraulic system, and relates to the field of hydraulic transmission. The plunger type hydraulic pump comprises a swash plate assembly, a driving shaft, a shell and an adjusting assembly; the swash plate assembly comprises a swash plate body and a bracket, and the swash plate body is rotatably arranged on the bracket; the driving shaft is provided with a first transmission part, the swash plate body is provided with a first clamping groove, and the first transmission part is in butt joint with the inner wall of the first clamping groove along the circumferential direction of the driving shaft; the casing is provided with the rotation support piece that rotates on the casing, rotates the support piece and wears to locate the casing along the radial direction of drive shaft, rotates support piece and leg joint, and adjusting part's regulation end is connected with rotation support piece. When the inclination angle of the swash plate body needs to be changed, the adjusting end of the adjusting component drives the rotating supporting piece to rotate, and then drives the bracket to rotate, so that the inclination angle of the bracket is adjusted. At this time, the inclination angle of the swash plate body is synchronously changed with the inclination angle of the bracket. The adjusting process is efficient and stable, and is beneficial to flexibly adjusting the displacement of the plunger hydraulic pump.

Description

Plunger type hydraulic pump and hydraulic system

Technical Field

The application relates to the field of hydraulic transmission, in particular to a plunger type hydraulic pump and a hydraulic system.

Background

Plunger hydraulic pumps are an important device of hydraulic systems. The oil suction and pressure oil can be realized by means of the reciprocating motion of the plunger in the cylinder body to change the volume of the sealed working cavity, and the oil suction and pressure oil suction device has the advantages of high rated pressure, compact structure, high efficiency, convenience in flow adjustment and the like.

According to the different working principles, plunger type hydraulic pumps are generally classified into single plunger pumps, horizontal plunger pumps, axial plunger pumps and radial plunger pumps. The axial plunger pump can be divided into a sloping cam type and a sloping cam type.

In a swash plate type axial plunger pump, the magnitude of the inclination angle of a swash plate determines the reciprocating stroke of a plunger, and thus the displacement of the pump is affected. However, the existing swash plate type axial plunger pump cannot efficiently and stably change the inclination angle of the swash plate, and the displacement of the pump cannot be flexibly adjusted.

Disclosure of Invention

In order to solve the problems existing in the prior art, one of the purposes of the present application is to provide a plunger type hydraulic pump.

The application provides the following technical scheme:

a plunger type hydraulic pump comprises a swash plate assembly, a driving shaft, a shell and an adjusting assembly;

the swash plate assembly is positioned in the shell and comprises a swash plate body and a bracket, and the swash plate body is rotatably arranged on the bracket around the axis direction of the swash plate body;

the driving shaft is provided with a first transmission part, the swash plate body is provided with a first clamping groove into which the first transmission part can be clamped, and the first transmission part is abutted with the inner wall of the first clamping groove along the circumferential direction of the driving shaft;

the rotary support piece is rotatably arranged on the shell, the rotary support piece penetrates through the shell along the radial line direction of the driving shaft, the rotary support piece is connected with the bracket, and the adjusting end of the adjusting component is connected with the rotary support piece.

As a further alternative scheme for the plunger type hydraulic pump, the adjusting assembly comprises an adjusting driving piece, a swinging rod and a deflector rod, wherein the driving end of the adjusting driving piece is connected with the swinging rod, the swinging rod is in running fit with the deflector rod, and the deflector rod is connected with the rotating support piece;

wherein, the driving lever is in sliding fit with the swing rod or the rotating support piece.

As a further alternative scheme of the plunger hydraulic pump, the adjusting assembly further comprises a rotating shaft, the swing rod is in running fit with the deflector rod through the rotating shaft, and the rotating shaft is in sliding fit with the swing rod or the deflector rod.

As a further alternative scheme of the plunger type hydraulic pump, a chute is arranged on the swing rod, the rotating shaft is arranged in the chute in a sliding manner, and the rotating shaft is connected with one end of the deflector rod, which is close to the swing rod.

As a further alternative scheme of the plunger type hydraulic pump, the rotating shaft is rotatably arranged in the sliding groove, and the rotating shaft is fixedly connected with the deflector rod.

As a further alternative scheme of the plunger type hydraulic pump, a limiting boss is arranged on the rotating support piece, a limiting groove is correspondingly arranged at one end, close to the rotating support piece, of the deflector rod, and the limiting boss is embedded in the limiting groove.

As a further alternative to the plunger type hydraulic pump, the swash plate assembly further includes a first bearing, and the swash plate body is rotatably provided on the bracket through the first bearing.

As a further alternative scheme for the plunger type hydraulic pump, the outer side wall of the swash plate body is provided with a shaft shoulder, and the swash plate body is provided with a check ring;

the first bearing is arranged around the swash plate body, one side of the first bearing abuts against the shaft shoulder, and the other side of the first bearing abuts against the check ring.

As a further alternative to the plunger hydraulic pump, a limit flange is provided on an inner side wall of the bracket, and the first bearing abuts against the limit flange.

Another object of the application is to provide a hydraulic system.

The application provides the following technical scheme:

a hydraulic system comprises the plunger type hydraulic pump.

The embodiment of the application has the following beneficial effects:

in the above-mentioned plunger hydraulic pump, the housing supports the bracket by rotating the support member, and the swash plate body is rotatably provided on the bracket about its own axis direction. During operation, the adjusting end of the adjusting assembly, the rotating supporting piece and the bracket are kept motionless, the inclination angle of the swash plate body is kept constant, and the driving shaft drives the first transmission piece to rotate. The first transmission piece is abutted with the inner wall of the first clamping groove along the circumferential direction of the driving shaft, and further drives the swash plate body to rotate when rotating along with the driving shaft, so that the plunger type hydraulic pump normally operates. In the process, the swash plate body rotates around the axis direction of the swash plate body, the rotation axis of the swash plate body is not overlapped with the rotation axis of the first transmission piece, and therefore the first transmission piece moves relative to the swash plate body along the axis direction of the driving shaft in the first clamping groove.

When the inclination angle of the swash plate body needs to be changed, the adjusting end of the adjusting component drives the rotating supporting piece to rotate, and then drives the bracket to rotate, so that the inclination angle of the bracket is adjusted. At this time, the inclination angle of the swash plate body is synchronously changed with the inclination angle of the bracket. The adjusting process is efficient and stable, and is beneficial to flexibly adjusting the displacement of the plunger hydraulic pump.

In order to make the above objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 shows an overall structure schematic diagram of a plunger hydraulic pump according to an embodiment of the present application;

fig. 2 shows a schematic diagram of an internal structure of a plunger hydraulic pump according to an embodiment of the present application;

FIG. 3 shows an enlarged schematic view at A in FIG. 2;

FIG. 4 illustrates a schematic cross-sectional view of a plunger hydraulic pump at a swash plate assembly provided by an embodiment of the application;

FIG. 5 is a schematic diagram showing the relationship between a swash plate assembly and a drive shaft in a plunger hydraulic pump according to an embodiment of the present application;

FIG. 6 illustrates a schematic cross-sectional view of a plunger hydraulic pump at a plunger assembly provided by an embodiment of the present application;

fig. 7 shows a schematic structural diagram of an oil distribution disc in a plunger type hydraulic pump according to an embodiment of the present application;

fig. 8 shows a schematic structural diagram of an adjusting assembly in a plunger hydraulic pump according to an embodiment of the present application.

Description of main reference numerals:

100-mounting seats; 200-a housing; 210-rotating the support; 211-limiting bosses; 300-driving a motor; 310-driving shaft; 311-a first transmission member; 312-a second transmission member; 313-a second bearing; 314-a first stop collar; 315-a second limiting ring; 316-spring; 400-swash plate assembly; 410-a swash plate body; 411-shaft shoulders; 412-a retainer ring; 413-a first card slot; 420-a bracket; 421-limit flanges; 430-a first bearing; 431-cage; 432-balls; 500-plunger assembly; 510-a plunger body; 511-a piston chamber; 512-second card slot; 520-piston; 600-oil distribution tray; 610-a first flow channel; 620-a second flow channel; 630-oil hole; 700-an adjustment assembly; 710-adjusting the drive; 720-swinging rod; 721-chute; 730—a toggle lever; 731-a limit groove; 740-spindle.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the application.

It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the templates herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Examples

Referring to fig. 1 and 2 together, the present embodiment provides a plunger hydraulic pump, specifically a straight-shaft swash plate type plunger pump, which includes a mounting base 100, a housing 200, a driving motor 300, a swash plate assembly 400, a plunger assembly 500, an oil distribution disc 600 and an adjusting assembly 700. The housing 200, the driving motor 300, and the adjustment assembly 700 are fixedly disposed on the mount 100, and the swash plate assembly 400 and the plunger assembly 500 are disposed within the housing 200. The oil distribution plate 600 is fixedly disposed at an end of the housing 200 remote from the driving motor 300, and cooperates with the swash plate assembly 400 and the plunger assembly 500 in the housing 200. In addition, the driving motor 300 has a driving shaft 310, and the driving shaft 310 penetrates into the housing 200 and is in driving connection with the swash plate assembly 400 and the plunger assembly 500.

Specifically, the housing 200 is cylindrical, and has one end closed and the other end open. The closed end of the housing 200 faces the driving motor 300, and the oil distribution plate 600 is fixedly provided at the open end of the housing 200.

Accordingly, the drive shaft 310 passes from the closed end of the housing 200 into the interior of the housing 200, and the axis of the drive shaft 310 coincides with the axis of the housing 200.

Referring to fig. 3, in particular, the swash plate assembly 400 includes a swash plate body 410 and a bracket 420. The swash plate body 410 and the bracket 420 are both ring-shaped, and the axis of the swash plate body 410 coincides with the axis of the bracket 420, and the swash plate body 410 is rotatably disposed inside the bracket 420 around its own axis direction.

In the present embodiment, the swash plate assembly 400 further includes a first bearing 430, and the swash plate body 410 is rotatably provided on the bracket 420 through the first bearing 430.

In some implementations of the present embodiment, the first bearing 430 is composed of a cage 431 and a plurality of balls 432, and the cage 431 is disposed around the swash plate body 410. The balls 432 are fitted in the holder 431 and are arranged in the circumferential direction of the swash plate body 410.

Correspondingly, the outer side wall of the swash plate body 410 is provided with a shaft shoulder 411, the shaft shoulder 411 is positioned on one side of the retainer 431 opposite to the closed end of the casing 200, and the shaft shoulder 411 abuts against one side of the retainer 431. A retainer 412 is fixedly provided on one side of the swash plate body 410 facing the closed end of the casing 200, and the retainer 412 abuts against the other side of the retainer 431.

In addition, an annular limiting flange 421 is integrally formed on the inner side wall of the bracket 420, and the limiting flange 421 abuts against one side of the retainer 431 facing the closed end of the housing 200.

In other embodiments of the present embodiment, the first bearing 430 may also be in other forms, such as a deep groove ball first bearing 430, a needle first bearing 430, and the like.

Referring to fig. 4, a rotation support 210 is rotatably disposed on the housing 200. The rotation support 210 is penetrated through the housing 200 along the radial direction of the housing 200 (and the radial direction of the driving shaft 310), and is connected with the bracket 420, so as to realize the rotation support of the housing 200 to the bracket 420.

When the plunger type hydraulic pump is operated, the rotation support 210 and the bracket 420 are kept stationary. Both the bracket 420 and the swash plate body 410 are in an inclined state, the inclination angle is the angle between the axis of the bracket 420 and the axis of the housing 200, and the inclination angle is kept constant.

Accordingly, the adjusting end of the adjusting assembly 700 is connected to the rotating support 210, and can drive the rotating support 210 to rotate, so as to adjust the inclination angle of the bracket 420, and further adjust the inclination angle of the swash plate body 410.

In some embodiments, the rotational support 210 is provided with two. The two rotation supports 210 are symmetrically disposed about the axis of the housing 200, and can stably support the bracket 420, and the adjustment end of the adjustment assembly 700 is connected to one of the rotation supports 210.

Referring to fig. 4 and 5, the driving shaft 310 is provided with a first transmission member 311, and the inner sidewall of the swash plate body 410 is provided with a first slot 413 into which the first transmission member 311 is engaged. The first transmission member 311 is in contact with the inner wall of the first engagement groove 413 in the circumferential direction of the drive shaft 310, and is movable in the first engagement groove 413 in the axial direction of the drive shaft 310.

When the plunger hydraulic pump works, the driving shaft 310 drives the first transmission member 311 to rotate, and the first transmission member 311 further drives the swash plate body 410 to rotate. The swash plate body 410 cooperates with the plunger assembly 500 and the oil distribution plate 600 to normally operate the plunger type hydraulic pump.

In this process, the swash plate body 410 rotates around its own axis direction, and the rotation axis 740 thereof does not coincide with the rotation axis 740 of the first transmission member 311, so that the first transmission member 311 moves relatively to the swash plate body 410 in the axial direction of the driving shaft 310 within the first catching groove 413.

In some embodiments, the first transmission member 311 is a pin shaft and is disposed on the driving shaft 310 along a radial direction of the driving shaft 310. Accordingly, the first clamping groove 413 penetrates the swash plate body 410 in the axial direction of the swash plate body 410.

Further, two first catching grooves 413 are provided on the inner sidewall of the swash plate body 410, and the two first catching grooves 413 are symmetrical with respect to the axis of the swash plate body 410. The two ends of the first transmission member 311 are respectively clamped into the first clamping grooves 413, so that the swash plate body 410 is uniformly stressed when the swash plate body 410 is driven to rotate.

Referring to fig. 2 and 6, in particular, the plunger assembly 500 includes a plunger body 510 and a plurality of pistons 520. The plunger body 510 is disposed around the driving shaft 310, and a side of the plunger body 510 facing the swash plate body 410 is provided with a plurality of piston chambers 511. The pistons 520 are slidably disposed in the corresponding piston chambers 511 in the axial direction of the driving shaft 310, and the piston 520 rod is ball-hinged with the swash plate body 410.

Referring to fig. 6, a second transmission member 312 is disposed on the driving shaft 310, a second clamping groove 512 into which the second transmission member 312 can be clamped is disposed on an inner sidewall of the plunger body 510, and the second transmission member 312 abuts against an inner wall of the second clamping groove 512 along a circumferential direction of the driving shaft 310.

When the plunger hydraulic pump is operated, the driving shaft 310 drives the second transmission member 312 to rotate, and the second transmission member 312 further drives the plunger body 510 to rotate. The rotational angular velocity of the plunger body 510 and the swash plate body 410 is the same, and the rotational axes 740 intersect obliquely.

Taking the illustrated angle as an example, during the counterclockwise rotation of the plunger body 510 and the swash plate body 410, the piston 520 at the left moves backward so that a hollow chamber is formed in the piston chamber 511 at the left, thereby sucking hydraulic oil. The piston 520 on the right moves forward so that pressure is generated in the piston chamber 511 on the right, thereby pushing out hydraulic oil.

In some embodiments, the second transmission member 312 is also a pin and is disposed through the driving shaft 310 along a radial direction of the driving shaft 310. Similarly, the second clamping grooves 512 penetrate the plunger body 510 along the axial direction of the plunger body 510, and the second clamping grooves 512 are symmetrically arranged with respect to the axial direction of the plunger body 510. The two ends of the second transmission member 312 are respectively clamped into the second clamping grooves 512, so that the plunger body 510 is uniformly stressed when the plunger body 510 is driven to rotate.

Referring again to fig. 2, further, a second bearing 313 is disposed between the plunger body 510 and the drive shaft 310. The driving shaft 310 is further sleeved with a first limiting ring 314, a second limiting ring 315 and a spring 316, the first limiting ring 314 is abutted against the second bearing 313, and the spring 316 is located between the first limiting ring 314 and the second limiting ring 315.

Referring to fig. 2 and 7 together, specifically, the oil distribution disc 600 abuts against the plunger body 510, and an arc-shaped first flow channel 610 and a second flow channel 620 are disposed on a side of the oil distribution disc 600 facing the plunger body 510.

The first flow channel 610 communicates with the piston chamber 511 located on the left side, and the second flow channel 620 communicates with the piston chamber 511 located on the right side.

In addition, a plurality of oil holes 630 are provided at a side of the oil distribution plate 600 facing away from the plunger body 510. A portion of the oil holes 630 communicate with the first flow passage 610, and the remaining oil holes 630 communicate with the second flow passage 620.

Referring to fig. 8, in particular, the adjustment assembly 700 includes an adjustment drive 710, a swing link 720, and a toggle lever 730. The driving end of the adjusting driving piece 710 is connected with a swing rod 720, and the swing rod 720 is in running fit with a deflector rod 730. The shift lever 730 is coupled to one of the rotational supports 210 as an adjustment end of the overall adjustment assembly 700. In addition, the lever 730 is slidably engaged with the swing link 720 or the rotation support 210.

Alternatively, the adjustment drive 710 employs a servo motor. The casing of the servo motor is fixedly arranged on the mounting seat 100, and the shaft of the servo motor is connected with the swing rod 720.

The swing rod 720 and the shift lever 730 form a link structure, and the adjustment driving member 710 can drive the rotation supporting member 210 to rotate through the link structure, thereby driving the bracket 420 to rotate, and adjusting the inclination angle of the bracket 420 and the swash plate body 410.

In this process, the shift lever 730 slides relatively to the swing link 720 or the rotation support 210, so that the length of the link structure can be adaptively adjusted.

In this embodiment, the adjustment assembly 700 further includes a rotation shaft 740, and the rotation shaft 740 is parallel to the shaft of the servo motor. The swing rod 720 is in running fit with the shift lever 730 through the rotating shaft 740, and the rotating shaft 740 is in sliding fit with the swing rod 720 or the shift lever 730.

Accordingly, the lever 730 is fixedly coupled to the rotary support 210. The rotation support 210 is provided with a limiting boss 211, one end of the deflector 730, which is close to the rotation support 210, is correspondingly provided with a limiting groove 731, and the limiting boss 211 is embedded in the limiting groove 731. When the shift lever 730 drives the rotation support member 210 to rotate, torque is transmitted through the limit boss 211.

In some embodiments of the present embodiment, the swing link 720 is provided with a sliding slot 721, and the sliding slot 721 is disposed along a radial direction of a shaft of the servo motor. The rotating shaft 740 is slidably disposed in the chute 721 and connected to an end of the lever 730 near the swing link 720.

The rotation shaft 740 may be rotatably disposed in the chute 721 and fixedly connected to the shift lever 730, or may be slidably disposed in the chute 721 and rotatably connected to the shift lever 730, or may be rotatably disposed in the chute 721 and rotatably connected to the shift lever 730.

Optionally, a rotary shaft 740 is rotatably disposed in the chute 721, and the rotary shaft 740 is fixedly connected to the lever 730.

In other embodiments of the present embodiment, a sliding slot 721 may be disposed on the lever 730, and the rotating shaft 740 may be disposed at an end of the swing rod 720 near the lever 730.

In another embodiment of the present application, the lever 730 may also be slidably engaged with the rotary support 210.

In the above-mentioned plunger type hydraulic pump, when the inclination angle of the swash plate body 410 needs to be changed, the adjustment driving member 710 is started, and the rotation supporting member 210 is driven to rotate by the link structure formed by the swing link 720 and the shift lever 730, so as to drive the bracket 420 to rotate, thereby adjusting the inclination angle of the bracket 420. At this time, the inclination angle of the swash plate body 410 is synchronously changed with the inclination angle of the bracket 420.

When the inclination angle of the swash plate body 410 becomes small, the stroke of the piston 520 becomes short, so that the displacement of the entire plunger type hydraulic pump becomes small.

After the axis of the swash plate body 410 coincides with the axis of the driving shaft 310, the bracket 420 and the swash plate body 410 are continuously driven to rotate, so that the swash plate body 410 is inclined in the opposite direction, and the oil inlet and outlet direction of the plunger type hydraulic pump can be adjusted.

In a word, the adjusting process is efficient and stable, and is beneficial to flexibly adjusting the displacement of the plunger hydraulic pump.

The embodiment also provides a hydraulic system, which comprises the plunger type hydraulic pump.

Any particular values in all examples shown and described herein are to be construed as merely illustrative and not a limitation, and thus other examples of exemplary embodiments may have different values.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application.

Claims

1. The plunger type hydraulic pump is characterized by comprising a swash plate assembly, a driving shaft, a shell and an adjusting assembly;

2. The plunger type hydraulic pump according to claim 1, wherein the adjusting assembly comprises an adjusting driving piece, a swinging rod and a deflector rod, the driving end of the adjusting driving piece is connected with the swinging rod, the swinging rod is in running fit with the deflector rod, and the deflector rod is connected with the rotating support piece;

3. The plunger hydraulic pump as set forth in claim 2 wherein said adjustment assembly further comprises a spindle through which said rocker is in rotational engagement with said lever, said spindle being in sliding engagement with either said rocker or said lever.

4. The plunger type hydraulic pump as set forth in claim 3, wherein a chute is provided on the swing link, the rotation shaft is slidably disposed in the chute, and the rotation shaft is connected to one end of the shift lever close to the swing link.

5. The plunger hydraulic pump as set forth in claim 4, wherein said shaft is rotatably disposed in said chute, said shaft being fixedly connected to said lever.

6. The plunger type hydraulic pump as set forth in claim 3, 4 or 5, wherein a limit boss is provided on the rotation support member, one end of the shift lever adjacent to the rotation support member is correspondingly provided with a limit groove, and the limit boss is embedded in the limit groove.

7. The plunger type hydraulic pump as set forth in any one of claims 1 to 5, wherein the swash plate assembly further includes a first bearing, and the swash plate body is rotatably provided on the bracket through the first bearing.

8. The plunger type hydraulic pump as set forth in claim 7, wherein the outer sidewall of the swash plate body has a shoulder, and a retainer ring is provided on the swash plate body;

9. The plunger hydraulic pump as set forth in claim 7, wherein the inner side wall of the bracket is provided with a limit flange, and the first bearing abuts against the limit flange.

10. A hydraulic system comprising a plunger hydraulic pump as claimed in any one of claims 1-9.