WO2001094787A1

WO2001094787A1 - Pump

Info

Publication number: WO2001094787A1
Application number: PCT/EP2001/006301
Authority: WO
Inventors: Wolfgang Reuter
Original assignee: Luk Fahrzeug-Hydraulik Gmbh & Co. Kg
Priority date: 2000-06-05
Filing date: 2001-06-01
Publication date: 2001-12-13
Also published as: ES2283416T3; DE10192360D2; DE50112376D1; EP1292769A1; EP1292769B1; DE10027812A1

Abstract

The invention relates to a pump, comprising a housing with a recess in which a pump unit is located. Said pump unit has a pump chamber which is formed by a pump chamber ring and at least one pressure plate positioned on said pump chamber ring; and a rotary-driven pump element which is located in the pump chamber. The inventive pump also comprises a housing cover which is fixed to the housing and seals the recess; and a pressure space which is limited by the recess and the pressure plate. The invention is characterised in that the housing cover and the pressure plate are configured as a single piece and in that at least one at least partially peripheral pocket which opens towards the edge of the pressure plate or an at least partially peripheral cavity is configured between the housing cover and the pressure plate.

Description

pump

description

The invention relates to a pump with a housing which has a recess in which a pump unit is arranged, which has a pump chamber formed by a pump chamber ring and at least one pressure plate lying on the pump chamber ring and a pump element which can be driven in rotation and which is arranged in the pump chamber , a housing cover closing the recess and fastened to the housing and with a pressure space delimited by the recess and the pressure plate.

Pumps of the type mentioned here are known. They have a housing in which a recess is formed. A pump unit is inserted into this recess. This pump unit has a pump chamber which is formed by a pump chamber ring and at least one pressure plate lying on the pump chamber ring. Two printing plates can also be provided. The pump unit further comprises a pump element which can be driven in rotation and is arranged in the pump chamber. The recess in the housing is closed by a housing cover. In the known pumps, one of the pressure plates rests on the housing cover or is pushed by the housing cover onto the pump chamber ring. In addition, the pump has a pressure chamber, that of the other pressure plate and the recess or directly from the wall the recess is limited. When the pump is operating, the medium conveyed by the rotary driven pump element is in the pressure chamber under pressure. This presses on the pressure plate, which in turn transmits this force to the pump chamber ring, which thus acts on the other pressure plate radially on the outside with an axially acting force which deforms the pressure plate lying against the housing cover and the housing cover itself. In addition, the pressure inside the pump element acts in such a way that the pressure plate and cover are curved outwards. This creates a leakage gap between the rotary-driven pump element and the cover-side pressure plate, which has an adverse effect on the volumetric efficiency of the pump.

In the prior art, attempts have been made to solve this problem by making the housing cover very rigid in order to largely prevent deformation of this housing cover. For this purpose, the housing cover was made particularly thick. This increases the size of the pump and also its weight.

Another known pump has attempted to solve this problem by making the pressure plate surface of the cover-side pressure plate facing the pump element convex. The production of this curved printing plate surface, however, requires a higher manufacturing effort.

It is therefore an object of the invention to provide a pump which is simple to manufacture and which is still characterized by a good volumetric efficiency.

This problem is solved with a pump that holds a housing u in which a recess is formed. A pump unit is arranged in the recess and has a pump chamber formed by a pump chamber ring and at least one pressure plate lying on the pump chamber ring. The pump unit also has a pump element which can be driven in rotation and is arranged in the pump chamber. The pump further comprises a housing cover closing the recess and a pressure chamber which is delimited at least in regions by the recess. According to the invention, the pump is characterized in that the housing cover and the cover-side pressure plate are formed in one piece and that between the housing cover and this pressure plate there is at least one pocket which is at least partially circumferential and which is open towards the edge of the pressure plate or an at least partially circumferential cavity. In the operation of the pump according to the invention, the axial pressure forces acting on the cover-side pressure plate from the pressure plate via the pump chamber ring act on a larger diameter than the opposing forces acting on the pressure plate from the cover and are transmitted via the cover to the pressure plate formed integrally with it , As a result, the pressure plate formed on the cover bends in the direction of the pump unit, thereby reducing the leakage gap. In a preferred embodiment, the depth of the pocket or cavity is approximately the same as the thickness of the pump chamber ring. As a result, the contact surface or edge or the lever arm of the pump chamber ring acts in the pocket or cavity area for the force transmission between the pump chamber ring and the pressure plate on the housing cover, so that the deflection of the pressure plate is correspondingly large. It is clear from this that the deflection of the pressure plate can be influenced by the depth of the pocket / the cavity.

In a preferred embodiment, the pocket or cavity side walls are approximately parallel to the pressure plate ring surface of the pressure plate facing the pump chamber ring. Such a bag is easy to manufacture.

In one embodiment, the depth of the pocket or cavity is constant. In another exemplary embodiment, the depth of the pocket or of the cavity can vary in the circumferential direction, as a result of which it is possible to adapt or influence the deflection as a function of the number of pressure ranges of the pump unit.

When the pump is depressurized, the pressure plate circular surface facing the pump element of the pressure plate formed in one piece with the housing cover is flat. Flat surfaces are particularly easy to manufacture. In one embodiment it is provided that when the pump is at a standstill or when the pump is not under pressure, the pressure plate ring area and the pressure plate circle area lie in one plane. Thus, the entire pressure plate surface facing the pump unit is made flat, so that the production of the housing cover with the one-piece pressure plate can be carried out particularly inexpensively.

The invention is explained in more detail below on the basis of an exemplary embodiment with reference to the drawing. Show it:

FIG. 1 shows a cross section through a pump, shown in a highly simplified manner, with a housing cover according to a first exemplary embodiment,

2 shows a housing cover of the pump according to FIGS

FIG. 3 shows a cross section through a pump with a very simplified representation

Housing cover according to a second embodiment.

The housing cover according to the invention described below with the pressure plate can be used for vane cell, blocking vane and roller cell pumps in which the pump element which can be driven in rotation is formed by a rotor, in which, depending on the type of pump, vanes or rollers are used or as a contour element is realized. However, it would also be conceivable to cover with a gear pump. Such pumps or their function are known per se, so that the precise configuration of the pump element which can be driven in rotation is not described in more detail below.

FIG. 1 shows, in a highly simplified manner, a pump 1 in cross section, which comprises a housing 2. A recess 3 is formed in the housing 2 and is closed by a housing cover 4. The housing cover 4 is firmly connected to the housing 2 via fastening means 5, for example screws.

In the recess 3, a pump unit 6 is arranged, which has a pump chamber 7, which consists of a pump chamber ring 8 and two pressure plates 11 and 10 resting on its ring surfaces 9 and 10

12 is formed. Instead of the pressure plate 11, the pump chamber 7 can also be closed on one side by the base 13 of the recess 3. One of the pressure plates 11 is adjacent to the bottom

13 of the recess 3. A pressure chamber 14 of the pump 1 lies between this pressure plate 11 and the base 13.

A medium delivered by a pump element 15 which can be driven in rotation is introduced into the pressure chamber 14, which has a connection to a pump-side consumer connection (not shown here). The pump element 15 which can be driven in rotation is the above-mentioned rotor of a vane, barrier vane or roller cell pump or a gearwheel Gear pump. This pump element 15 is driven in rotation by a drive shaft, not shown here, which is mounted in the housing 2. A so-called leakage gap 16 is formed between the pump element 15 arranged in the pump chamber 7 and the cover-side pressure plate 12 facing away from the pressure chamber 14.

The housing cover 4 and the pressure plate 12 are formed in one piece, the diameter of the housing cover 4 being larger than that of the pressure plate 12. With its radially outer edge region 17, the housing cover 4 lies on the edge of the housing. Openings 18 are formed in this edge area 17, through which the fastening means 5 engage. A circumferential pocket 19, which is designed to be open toward the pressure plate edge 20, is introduced into the one-piece component comprising the housing cover 4 and the pressure plate 12. The pocket side walls 21 and 22 run essentially parallel to a pressure plate ring surface 23 of the pressure plate 12 facing the pump chamber ring 8. The pressure plate ring surface 23 lies on the ring surface 10 of the pump chamber ring. In the exemplary embodiment, the depth T of the circumferential pocket 19 is somewhat greater than the thickness S of the pump chamber ring 8. The depth T of the pocket is constant in the exemplary embodiment shown. However, it becomes clear that the depth T of the pocket can also vary in the circumferential direction or circumferential direction, in particular if the pump has more than one pressure range, as is the case with the above-mentioned pumps. penarten is often the case or if the pump chamber ring 8 is not completely circular. In particular in the case of vane, barrier vane and roller cell pumps, at least two suction and two pressure areas can be formed. The pressure area (s) are in fluid communication with the pressure chamber 14, so that the pressure of the conveyed medium is applied to it.

FIG. 1 also shows that the pressure plate circular surface 26 of the cover-side pressure plate 12 facing the rotary-driven pump element 15 is essentially flat. It is therefore clear that both the pressure plate ring surface 23 and the pressure plate circular surface 26 lie in one plane, that is to say are essentially planar. “Essentially” means that so-called pressure and suction recesses can be present in the pressure plate circular surface 26, which can also be formed on the pressure plate 11 on the surface facing the pump element 15.

Depending on the width B of the pocket 19, a more or less thick spacer 27 is formed between the housing cover 4 and the pressure plate 12, the cross section of which is smaller than that of the housing cover 4 and the pressure plate 12. A transmission of a supporting force (double arrows 28) from the housing cover 4 via the spacer or intermediate piece 27 to the pressure plate 12 is only possible in a force transmission area K which is opposite the opening 29 of the pump chamber ring 8. During operation of the pump, the pressure chamber 14 is pressurized with the pressure of the medium conveyed. Forces thus act on the pressure plate 11, which would force this pressure plate 11 away from the base 13 of the recess 3. These forces (arrow 31) are transmitted from the pressure plate 11 via an essentially circular ring surface 30 to the ring surface 9 on the pump chamber ring 8. The pump chamber ring 8 in turn transmits these forces (arrows 31) to the pressure plate ring surface 23 on the pressure plate 12 via its ring surface 10. It is clear that the contact surface between the ring 8 and the pressure plate 11 or 12 is not necessarily circular. It can also be elliptical. In addition, there may be recesses between the pressure plate 11 or 12 and the ring 8 in the area of their contact surfaces, which can form the suction connection, for example. These forces 31 act over a larger diameter range than the forces 28 in the supporting force transmission range K from the housing cover 4 to the pressure plate 12.

In FIG. 2, the deformation of the housing cover 4 and the pressure plate 12 resulting from the forces 31 and 28 and the forces from the pump chamber 7 is shown in a greatly exaggerated manner. It is clear that the pressure plate 12 forms a curvature on its pressure plate circular surface 26, the belly of which protrudes into the leakage gap 16, so that the gap width of the leakage gap 16 is reduced, which increases the volumetric efficiency of the pump 1. By the from the pressure plate

11 and the pump chamber ring 8 on the pressure plate

12 transmitted forces 31, the cover 4 after curved outside since it is only fastened to the housing 2 with the fastening means 5 in its edge region 17.

With the housing cover 4, which is also referred to as a buckling or rocking cover, and the pressure plate 12 formed in one piece with the housing cover 4, a single component with two different bending shapes is thus realized, the two bending shapes being in opposite directions, i.e. the formation of a belly takes place in opposite directions. However, these two bending forms are brought about by means of a single force component, namely the force 31, against the holding forces of the fastening means 5.

FIG. 3 shows a further exemplary embodiment of a housing cover 4 with a pressure plate 12 formed thereon in one piece. The same or equivalent parts as in FIGS. 1 and 2 are provided with the same reference symbols in FIG. 3. In this housing cover 4, instead of the pocket 19, a cavity 19 'is formed which, unlike the pocket 19, is designed with an open edge. Such a cavity 19 'can be produced, for example, by a so-called lost core if the one-piece component is cast from the housing cover 4 and the pressure plate 12 or, if appropriate, also sintered. Of course, it is clear that the depth T of the cavity 19 'or its width B is variable in order to be able to influence the deflection. It is also conceivable, as is also the case with the pocket 19, the cavity 19 ′ in the pressure plate 12 more or less to be arranged at a distance from the surface 10 of the pump chamber ring 8. In addition, as shown in FIG. 3, the pressure plate 12 can protrude beyond the outer circumferential surface of the ring 8. It is expressly pointed out that the configurations or arrangements mentioned above in connection with the pocket 19 also apply to the cavity 19 '.

It can thus be seen that this one-piece component comprising the housing cover 4 and the pressure plate 12 provides a very simple and inexpensive measure for reducing the leakage gap 16. The housing cover 4 and the pressure plate 12 therefore do not have to be made particularly thick or rigid. Rather, the invention makes use of a predeterminable elastic material bend on the cover 4 and the pressure plate. The pump 1 is thus characterized by an improved volumetric efficiency.

The patent claims submitted with the application are proposals for formulation without prejudice to further patent protection. The applicant reserves the right to claim further combinations of features previously only disclosed in the description and / or the drawings.

Back-references used in sub-claims indicate the further development of the subject matter of the main claim through the features of the respective sub-claim; they are not considered to be delayed in achieving an independent, opposing understand protection for the combinations of features of the related subclaims.

Since the subjects of the subclaims can form their own and independent inventions with regard to the prior art on the priority date, the applicant reserves the right to make them the subject of independent claims or declarations of division. They can furthermore also contain independent inventions which have a design which is independent of the objects of the preceding subclaims.

The exemplary embodiments are not to be understood as a restriction of the invention. Rather, numerous changes and modifications are possible within the scope of the present disclosure, in particular such variants, elements and combinations and / or materials, for example by combining or modifying individual ones, in conjunction with those in the general description and embodiments as well Features or elements or process steps described in the claims and contained in the drawings can be removed by the person skilled in the art with regard to the solution of the task and lead to a new object or to new process steps or process step sequences through combinable features, also insofar as they are manufacturing, testing and Concern working procedures.

Claims

Expectations

1. Pump with a housing which has a recess in which a pump unit is arranged, which has a pump chamber formed by a pump chamber ring and at least one pressure plate lying on the pump chamber ring and a rotationally drivable pump element which is arranged in the pump chamber, the recess sealing housing cover, fastened to the housing, and with a pressure space delimited by the recess and the pressure plate, characterized in that the housing cover and the pressure plate are formed in one piece and that between the housing cover and this pressure plate at least one circumferential, at least regionally, open to the pressure plate edge Pocket or an at least partially surrounding cavity is formed.

2. Pump, in particular according to claim 1, characterized in that the depth of the pocket or the cavity corresponds approximately to the thickness of the pump chamber ring.

3. Pump, in particular according to claim 1 or 2, characterized in that the pocket or cavity side walls are approximately parallel to the pressure plate ring face of the pressure plate facing the pump chamber ring.

4. Pump, in particular according to one of the preceding claims, characterized in that the depth of the pocket or the cavity is constant.

5. Pump, in particular according to one of claims 1 to 3, characterized in that the depth of the pocket or the cavity varies in the circumferential direction.

6. Pump, in particular according to one of the preceding claims, characterized in that in

Standstill of the pump the pressure plate circular surface facing the pump element is flat.

7. Pump, in particular according to one of the preceding claims, characterized in that in

When the pump is at a standstill, the pressure plate ring area and the pressure plate circle area lie in one plane.

8. Pump with a housing which has a recess in which a pump unit is arranged, which has a pump chamber formed by a pump chamber ring and at least one pressure plate lying on the pump chamber ring and a rotationally drivable pump element which is arranged in the pump chamber, the recess sealing housing cover fastened to the housing, and with a pressure space delimited by the recess and the pressure plate, characterized by at least one inventive feature disclosed in the application documents.