CN214092177U - Sliding shoe, plunger pump and hydraulic system - Google Patents

Abstract

The utility model provides a sliding shoe, including interconnect's first body and second body, first body is equipped with the ball socket dorsad second body one side, is equipped with the through-hole on the inner wall of ball socket, and the through-hole communicates with one side of second body dorsad first body, and the length of through-hole is n with the ratio in aperture, and n is less than or equal to 0.5. The utility model also provides a plunger pump, including above-mentioned piston shoes, plunger bulb and driving medium, the plunger bulb inlays in the ball socket, and the second body offsets with the driving medium to one side of first body dorsad. The utility model also provides a hydraulic system, including above-mentioned plunger pump. The through hole with the length-aperture ratio not greater than 0.5 is adopted to receive the hydraulic oil in the plunger cavity, so that the resistance of the hydraulic oil in the plunger cavity when the hydraulic oil permeates into the through hole is smaller. More hydraulic oil enters the through hole from the plunger cavity and then diffuses to the inner wall of the ball socket and one side of the second body, which is back to the first body, so that a stable oil film is formed, the sliding shoes are not easy to wear, and the service life of the sliding shoes is prolonged.

Description

Sliding shoe, plunger pump and hydraulic system

Technical Field

The utility model relates to an engineering machine tool field especially relates to a piston shoes, plunger pump and hydraulic system.

Background

In the fields of walking hydraulic pressure and industrial hydraulic pressure, the plunger pump has the advantages of small volume, light weight, high power density, large displacement and the like, and is widely applied to machinery such as metallurgy, engineering, mines, ships and the like and other hydraulic transmission systems.

In the plunger pump, there are many kinematic pairs, such as a plunger-slipper pair formed by a slipper and a plunger ball head, a swash plate-slipper pair formed by a slipper and a swash plate, and the like. Among them, a swash plate is commonly used in an axial plunger pump to transmit power of a driving shaft to a slipper. For radial piston pumps, an eccentric is often used to transmit the power of the drive shaft, and the correspondingly formed kinematic pair is an eccentric-slipper pair.

The plunger-slipper pair and the swash-plate-slipper pair (or eccentric-slipper pair) are two important kinematic pairs that affect the performance of the plunger pump, and therefore, the performance of the slipper has a significant impact on the performance of the plunger pump. In the actual use process, the contact surface of the slipper and the plunger ball head and the contact surface of the slipper and the swash plate or the eccentric wheel are worn, and even the phenomenon of 'burning the slipper' occurs in severe cases, so that the service life of the slipper is short.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems of abrasion and short service life of the sliding shoes in the prior art, one of the purposes of the utility model is to provide a sliding shoe.

The utility model provides a following technical scheme:

a piston shoe is applied to a plunger pump and comprises a first body and a second body which are connected with each other, a ball socket is arranged on one side, back to the second body, of the first body, the inner wall of the ball socket is communicated with one side, back to the first body, of the second body through a through hole, the ratio of the length of the through hole to the aperture is n, and n is less than or equal to 0.5.

As a further optional scheme for the sliding shoe, a first oil drainage groove is formed in the inner wall of the ball socket, the first oil drainage groove is annular, the inner wall of the ball socket is divided by the first oil drainage groove to form a first sealing area and a first auxiliary supporting area, and the first sealing area is located between the first oil drainage groove and the through hole.

As a further optional scheme for the sliding shoe, a first oil drainage hole is formed in the first body, and the outer surface of the first body is communicated with the first oil drainage groove through the first oil drainage hole.

As a further alternative to the sliding shoe, an axis of the first oil drainage groove coincides with an axis of the through hole.

As a further optional scheme for the sliding shoe, a second oil drainage groove is formed in one side of the second body, which faces away from the first body, and is annular, the second oil drainage groove separates one side of the second body, which faces away from the first body, to form a second sealing area and a second auxiliary supporting area, and the second sealing area is located between the second oil drainage groove and the through hole.

As a further optional scheme for the sliding shoe, a second oil drainage hole is formed in the second body, the second oil drainage hole communicates the outer surface of the second body with the second oil drainage groove, and the second oil drainage hole is not connected with one side of the second body, which faces away from the first body.

As a further alternative to the sliding shoe, an axis of the second oil drainage groove coincides with an axis of the through hole.

As a further alternative to the slipper shoe, any cross section of the ball socket is smaller than the largest cross section of the ball in which the ball socket is located.

Another object of the present invention is to provide a plunger pump.

The utility model provides a following technical scheme:

the plunger pump is applied to a hydraulic system and comprises the piston shoe, a plunger ball head and a transmission part, wherein the plunger ball head is embedded in a ball socket, and one side, back to the first body, of the second body is abutted to the transmission part.

It is a further object of the present invention to provide a hydraulic system.

The utility model provides a following technical scheme:

a hydraulic system comprises the plunger pump.

The embodiment of the utility model has the following beneficial effect:

the through hole with the length-aperture ratio not greater than 0.5 is adopted to receive the hydraulic oil in the plunger cavity, so that the resistance of the hydraulic oil in the plunger cavity when the hydraulic oil permeates into the through hole is smaller. More hydraulic oil enters the through hole from the plunger cavity and then diffuses to the inner wall of the ball socket and one side of the second body, which is back to the first body, and stable oil films are formed between the sliding shoes and the plunger ball head and between the sliding shoes and the swash plate or the eccentric wheel, so that the sliding shoes are not easy to wear, and the service life of the sliding shoes is prolonged.

In order to make the aforementioned and other objects, features and advantages of the present invention 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 invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic view showing the overall structure of a slipper provided in embodiment 1 of the present invention;

FIG. 2 shows a schematic cross-sectional view A-A of FIG. 1;

fig. 3 is a schematic view showing the overall structure of the slipper provided in embodiment 2 of the present invention;

FIG. 4 shows a schematic cross-sectional view along B-B of FIG. 3;

fig. 5 shows a schematic structural diagram of the second body in the slipper provided in embodiment 2 of the present invention.

Description of the main element symbols:

1-a first body; 11-a ball and socket; 111-a first sealing area; 112-a first auxiliary support area; 12-a through hole; 13-a first drainage groove; 14-a first drainage hole; 15-a groove; 2-a second body; 21-a second oil drainage groove; 22-a second drainage hole; 23-a second sealing area; 24-second auxiliary support area.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.

It will be understood that when an element is referred to as being "secured 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 as used herein are for illustrative purposes only.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited 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 invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The piston shoe is one of the important components of the plunger pump, and forms a plunger-piston shoe pair with a plunger ball head and also forms a swash plate-piston shoe pair (or an eccentric wheel-piston shoe pair) with a swash plate (or an eccentric wheel). When the plunger piston is used, relative movement exists between the sliding shoe and the plunger ball head, and between the sliding shoe and the swash plate or the eccentric wheel.

In order to reduce friction, reduce energy loss and protect parts from abrasion, lubricating grease is required to be arranged between a sliding shoe and a plunger ball head, and between the sliding shoe and a swash plate or an eccentric wheel. In fact, the plunger ball head is provided with a small hole, the small hole is communicated with the outer surface of the plunger ball head and the plunger cavity to lead out hydraulic oil in the plunger cavity, and the hydraulic oil is further diffused between the sliding shoe and the plunger ball head to form an oil film which is directly used as lubricating oil.

On the other hand, the sliding shoe is provided with a damping hole with a small diameter, and the ratio of the length to the hole diameter is not less than four. The damping holes are communicated with two ends of the sliding shoe, and hydraulic oil is led between the sliding shoe and the swash plate or the eccentric wheel to form an oil film as lubricating oil.

Because the hydraulic oil flows in the damping holes smoothly, less hydraulic oil flows into the damping holes from the plunger cavity, less lubricating oil permeates between the sliding shoes and the plunger ball head and between the sliding shoes and the swash plate or the eccentric wheel, and the formed oil film is easy to damage.

In the actual use process, the condition that the slipper is in direct contact with a plunger ball head, the slipper is in direct contact with a swash plate or an eccentric wheel, so that all parts are abraded, even the phenomenon of 'burning the slipper' occurs in serious conditions, and the service life is short.

Example 1

Referring to fig. 1 and fig. 2, the present embodiment provides a slipper for use in various plunger pumps. The slipper consists of a first body 1 and a second body 2, wherein one side of the first body 1, which is back to the second body 2, is provided with a ball socket 11 matched with a plunger ball head, and one side of the second body 2, which is back to the first body 1, is matched with a driving part such as a swash plate or an eccentric wheel. In addition, a through hole 12 is opened on the inner wall of the ball socket 11, and the through hole 12 is communicated with one side of the second body 2, which is back to the first body 1.

The first body 1 is cylindrical, and the second body 2 and one end of the first body 1 are integrally formed or welded and fixed. The ball socket 11 is arranged on the end surface of the first body 1, which is opposite to one end of the second body 2, and the center of the ball socket 11 is positioned on the axis of the first body 1.

The through hole 12 is a circular hole whose axis coincides with the axis of the first body 1. When the plunger ball head is assembled with the first body 1, the through hole 12 is opposite to the small hole at the tail end of the plunger ball head, and hydraulic oil in the plunger cavity seeps out from the small hole and directly enters the through hole 12.

The ratio of the length of the through hole 12 to the aperture is recorded as n, and n is less than or equal to 0.5. The flow of hydraulic oil into the through bore 12 is much less resistant than the damping bore, and more hydraulic oil flows from the plunger chamber into the through bore 12. One part of hydraulic oil is diffused between the sliding shoe and the plunger ball head, and the other part of hydraulic oil is diffused between the sliding shoe and the swash plate or the eccentric wheel.

Because hydraulic oil can be supplied in a sufficient amount, stable oil films can be formed between the sliding shoes and the plunger ball heads and between the sliding shoes and the swash plate or the eccentric wheel, and the oil films are not easy to damage. Therefore, the possibility of direct contact between the sliding shoes and the plunger ball head and between the sliding shoes and the swash plate or the eccentric wheel is reduced, the sliding shoes are not easy to wear, and the service life of the sliding shoes is prolonged.

Example 2

Referring to fig. 3 to 5, the present embodiment provides a slipper for a radial piston pump, including a first body 1 and a second body 2. The first body 1 is matched with a plunger ball head in the radial plunger pump to form a plunger-slipper pair, and the second body 2 is matched with an eccentric wheel in the radial plunger pump to form an eccentric wheel-slipper pair.

In particular, the first body 1 is cylindrical. One end of the first body 1 and the second body 2 are integrally formed, a ball socket 11 is arranged on the end face of the other end of the first body 1, the center of the ball socket 11 is located on the axis of the first body 1, and the plunger ball head is embedded in the ball socket 11.

In the existing plunger pump, the contact surface of the plunger ball head and the sliding shoe is often larger than a hemispherical surface, and the conditions of inflexible rotation, clamping stagnation and the like of the plunger ball head exist when the plunger ball head and the sliding shoe move relatively.

To address this problem, in the present embodiment, any cross section of the ball socket 11 is smaller than the maximum cross section of the ball in which the ball socket 11 is located, in other words, the inner diameter of the end of the ball socket 11 facing away from the second body 2 is smaller than the diameter of the ball in which the ball socket 11 is located. Because the contact surface between the plunger ball head and the sliding shoe is reduced, the plunger ball head and the sliding shoe can flexibly move relatively without clamping stagnation.

If the area of the ball socket 11 is further reduced, a groove 15 may be formed on the end surface of the first body 1 facing away from the second body 2. The groove 15 is circular, the inner diameter of the groove is larger than the diameter of the ball where the ball socket 11 is located, and the axis of the groove 15 coincides with the axis of the first body 1. As the depth of the recess 15 increases, the area of the socket 11 gradually decreases, balancing the stability of the connection with the flexibility of rotation.

The bottom of the inner wall of the ball socket 11 is provided with a through hole 12, the through hole 12 is circular, the axis of the through hole 12 coincides with the axis of the first body 1, and one end of the through hole 12, which is back to the ball socket 11, is communicated to one side of the second body 2, which is back to the first body 1.

In the working process, the hydraulic oil in the plunger cavity can permeate into the through hole 12 and then further diffuse to the space between the inner wall of the ball socket 11 and the plunger ball head and the space between the second body 2 and the eccentric wheel to form oil films, so that the friction is reduced, the energy loss is reduced, and parts are protected from being abraded.

Aiming at the problems that hydraulic oil is not smooth in flowing, insufficient in supply and incapable of forming a stable oil film due to the fact that a damping hole is formed in an existing plunger pump, in the embodiment, the ratio of the length of the through hole 12 to the aperture is not larger than 0.5. Specifically, the diameter of the through-hole 12 is not less than 5 mm.

The hydraulic oil is subject to a much smaller resistance to flow into the through-hole 12 than the orifice. More hydraulic oil flows into the through hole 12 from the plunger cavity and can be supplied in sufficient quantity, so that stable oil films are formed between the inner wall of the ball socket 11 and the plunger ball head and between the second body 2 and the eccentric wheel and are not easy to damage. Therefore, the possibility that the inner wall of the ball socket 11 is in direct contact with the plunger ball head and the second body 2 is in direct contact with the eccentric wheel is reduced, the sliding shoe is not easy to wear, and the service life of the sliding shoe is prolonged.

When the hydraulic oil diffuses from the through hole 12 to the inner wall of the ball socket 11 and the plunger ball head, the farther the distance from the through hole 12 is, the less easy the hydraulic oil is to permeate, and the gap between the inner wall of the ball socket 11 and the plunger ball head cannot be fully filled with the hydraulic oil. Although the area of the ball socket 11 in this embodiment is small, there is a possibility that hydraulic oil is difficult to penetrate to the inner wall of the ball socket 11 at the end facing away from the second body 2.

Therefore, in the present embodiment, the inner wall of the ball socket 11 is opened with the first oil drainage groove 13. The first oil drainage groove 13 is annular, the axis of the first oil drainage groove is coincident with the axis of the first body 1, and the notch of the first oil drainage groove 13 faces the axis of the first body 1.

The first oil drainage groove 13 divides the inner wall of the ball socket 11 into two regions, wherein the region between the first oil drainage groove 13 and the through hole 12 is a first sealing region 111, and the other region is a first auxiliary support region 112.

Along the circumferencial direction of first body 1, first draining groove 13 is everywhere equal with the distance between through-hole 12, and is less than the distance between ball socket 11 one end of second body 2 dorsad and through-hole 12, can guarantee that the hydraulic oil in the through-hole 12 permeates to in the first draining groove 13 to be covered with whole first sealed region 111.

In the working process, the included angle between the axis of the plunger and the axis of the first body 1 is changed in a small range, and the bearing force between the plunger ball head and the ball socket 11 is mainly concentrated on the first sealing area 111. The oil film on the first sealing area 111 can be stably maintained, namely, the lubricating and wear-resisting functions can be achieved.

In contrast, the first additional bearing area 112 acts as an additional bearing, and the pressure between the plunger ball and the first additional bearing area 112 is low. The oil film on the first auxiliary bearing area 112, although less stable than the oil film on the first sealing area 111, is not easily broken.

On the other hand, the first drain groove 13 also functions to store hydraulic oil. When the hydraulic oil entering the through hole 12 from the plunger cavity is reduced, the hydraulic oil in the first oil drainage groove 13 can be supplemented between the inner wall of the ball socket 11 and the plunger ball head to provide lubrication.

Specifically, in the present embodiment, the width and the depth of the first oil drainage groove 13 are not less than 2 mm.

In the working process, the hydraulic oil in the plunger cavity continuously permeates into the through hole 12, the hydraulic oil in the through hole 12 continuously permeates into the first sealing area 111 and enters the first oil drainage groove 13, and the hydraulic oil in the first oil drainage groove 13 can be gradually increased. When too much hydraulic oil is accumulated, the plunger ball head and the inner wall of the ball socket 11 are propped open, so that the gap between the plunger ball head and the inner wall of the ball socket 11 is enlarged, and the sealing property is further deteriorated. To avoid this, the first body 1 is provided with a first oil drainage hole 14.

The first oil drainage hole 14 is arranged along the radial line direction of the first body 1, one end of the first oil drainage hole 14 is communicated with the bottom of the first oil drainage groove 13, and the other end of the first oil drainage hole 14 is communicated with the outer side wall of the first body 1. When the hydraulic oil in the first drain groove 13 is accumulated excessively, the excess hydraulic oil can be drained from the first drain hole 14.

In the present embodiment, the second body 2 is provided in a rectangular parallelepiped shape. One side of the second body 2 facing the first body 1 is square, one side of the second body 2 facing away from the first body 1 is provided with an arc surface matched with the side wall of the eccentric wheel, and the through hole 12 is communicated with the arc surface.

When the hydraulic oil diffuses from the through hole 12 to the space between the second body 2 and the eccentric wheel, the farther the distance from the through hole 12 is, the less the hydraulic oil is easy to permeate, and the gap between the second body 2 and the eccentric wheel cannot be fully filled with the hydraulic oil.

Therefore, in the present embodiment, a second oil drainage groove 21 is formed on a side of the second body 2 facing away from the first body 1. The second oil drainage groove 21 is annular, the axis of the second oil drainage groove coincides with the axis of the through hole 12, and the notch of the second oil drainage groove 21 faces away from the first body 1.

The second oil drainage groove 21 divides one side of the second body 2, which faces away from the first body 1, into two areas, wherein the area between the second oil drainage groove 21 and the through hole 12 is a second sealing area 23, and the area on the periphery of the second oil drainage groove 21 is a second auxiliary supporting area 24.

In the circumference of along through-hole 12, second draining groove 21 is everywhere equal with the distance between through-hole 12, and is less than the second body 2 and the distance between the border and the through-hole 12 of first body 1 one side dorsad, can guarantee that the hydraulic oil in the through-hole 12 permeates to in the second draining groove 21 to be covered with whole second sealed area 23.

During operation, the bearing force between the eccentric and the second body 2 is mainly concentrated on the second sealing area 23. The oil film on the second sealing area 23 can be stably maintained, i.e. the lubricating and wear-resisting functions can be achieved.

In contrast, the second auxiliary bearing region 24 acts as an auxiliary bearing, and the pressure between the eccentric and the second auxiliary bearing region 24 is low. The oil film on the second auxiliary bearing area 24, although less stable than the oil film on the second sealing area 23, is also less prone to break.

On the other hand, the second drain groove 21 also functions to store hydraulic oil. When the hydraulic oil entering the through hole 12 from the plunger cavity is reduced, the hydraulic oil in the second oil drainage groove 21 can be supplemented between the second body 2 and the eccentric wheel to provide lubrication.

In the working process, the hydraulic oil in the plunger cavity continuously seeps into the through hole 12, the hydraulic oil in the through hole 12 continuously seeps through the second sealing area 23 and enters the second oil drainage groove 21, and the hydraulic oil in the second oil drainage groove 21 gradually increases. Hydraulic oil piles up and can strut eccentric wheel and second body 2 when too much, makes the space grow between eccentric wheel and the second body 2, and then leads to the leakproofness variation. To avoid this, the second body 2 is provided with a second drain hole 22.

The second oil drainage hole 22 is parallel to the first oil drainage hole 14, one end of the second oil drainage hole 22 is communicated with the bottom of the side wall of the second oil drainage groove 21, and the other end of the second oil drainage hole 22 is communicated with the outer side wall of the second body 2. When the hydraulic oil in the second drain groove 21 is accumulated excessively, the excess hydraulic oil can be drained from the second drain hole 22.

In the known plunger pump, a similar recess to the second oil drainage opening 22 is also present for draining excess hydraulic oil between the sliding shoe and the eccentric or swash plate. However, the notch is directly arranged on the bearing surface of the sliding shoe facing the eccentric wheel or the swash plate, the integrity of the bearing surface is damaged, and the notch is easy to wear, so that the performance and the service life of the sliding shoe are influenced.

In the embodiment, the second oil drainage hole 22 is not directly communicated with the side of the second body 2 opposite to the first body 1, so that the integrity of the second auxiliary supporting area 24 is not damaged, and the condition that the second auxiliary supporting area 24 is abraded is avoided.

The embodiment also provides a plunger pump, which is applied to a hydraulic system and comprises a plunger ball head, a transmission part and the sliding shoe. Specifically, the plunger pump is a radial plunger pump, and the transmission part is an eccentric wheel. Wherein, the plunger ball is embedded in the ball socket 11, and the eccentric wheel is propped against one side of the second body 2 back to the first body 1.

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

In all examples shown and described herein, any particular value should be construed as merely exemplary, and not as a limitation, and thus other examples of example embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

The above-described embodiments are merely illustrative of several embodiments of the present invention, which are described in detail and specific, but not intended to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention.

Claims (10)

1. The piston shoe is characterized by being applied to a plunger pump and comprising a first body and a second body which are connected with each other, wherein a ball socket is arranged on one side of the first body, which faces away from the second body, a through hole for receiving hydraulic oil in a plunger cavity is formed in the inner wall of the ball socket, the through hole is communicated with one side, which faces away from the first body, of the second body, the ratio of the length to the aperture of the through hole is n, and n is less than or equal to 0.5.

2. The slipper of claim 1, wherein a first oil drainage groove is formed in an inner wall of the ball socket, the first oil drainage groove is annular, the first oil drainage groove separates the inner wall of the ball socket to form a first sealing region and a first auxiliary support region, and the first sealing region is located between the first oil drainage groove and the through hole.

3. The slipper of claim 2, wherein the first body defines a first oil drainage hole therein, the first oil drainage hole communicating the outer surface of the first body with the first oil drainage groove.

4. The slipper of claim 2, wherein an axis of the first oil drainage groove coincides with an axis of the through hole.

5. The slipper of claim 1, wherein a side of the second body facing away from the first body is provided with a second oil drainage groove, the second oil drainage groove being annular and separating a side of the second body facing away from the first body to form a second sealing region and a second auxiliary support region, the second sealing region being located between the second oil drainage groove and the through hole.

6. The slipper of claim 5, wherein the second body defines a second drainage aperture, the second drainage aperture communicating the outer surface of the second body with the second drainage groove, and the second drainage aperture being unconnected to a side of the second body facing away from the first body.

7. The slipper of claim 5, wherein an axis of the second oil drainage groove coincides with an axis of the through hole.

8. The slipper of claim 1, wherein any cross-section of the socket is less than a maximum cross-section of a ball in which the socket is located.

9. Plunger pump, characterized in that it is applied in a hydraulic system, comprising a slipper according to any one of claims 1-8, a plunger ball embedded in said socket, and a transmission element against which the side of said second body facing away from said first body abuts.

10. A hydraulic system comprising a plunger pump as claimed in claim 9.

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