AU762304B2

AU762304B2 - Pump for generating pressure or negative pressure

Info

Publication number: AU762304B2
Application number: AU39635/00A
Authority: AU
Inventors: Fritz-Martin Scholz
Original assignee: Rietschle Werner GmbH and Co KG; Werner Rietschle GmbH and Co KG
Current assignee: Werner Rietschle GmbH and Co KG
Priority date: 1999-03-22
Filing date: 2000-03-22
Publication date: 2003-06-19
Anticipated expiration: 2020-03-22
Also published as: JP2002540346A; WO2000057062A1; DE50005415D1; KR20020019892A; AU3963500A; CN1365432A; EP1163450A1; ATE260412T1; KR100681804B1; HK1048844A1; EP1163450B1; DE29905249U1; WO2000057062B1; CN1324239C

Abstract

The invention relates to a pump for generating pressure or negative pressure, comprising a chamber having a high pressure branch and a low pressure branch. Two multi-bladed rotors (28, 30) are mounted on two shafts (20, 22) that are staggered relative to one another in the pump chamber (32). A drive mechanism is minted on the front face of the rotors and a housing lid is placed on the opposite side of said rotors. The housing lid (34) is pot-shaped. Both the high pressure branch (42) and the low pressure branch (40) are integrated into the housing lid (34).

Description

Pump for Generating Pressure or Negative Pressure Introduction The invention relates to a pump for generating pressure or negative pressure, comprising a pump chamber which has a high-pressure port and a low-pressure port, two rotors having at least two blades and fitted to two parallel shafts in the pump chamber that are offset to each other, a drive arranged on an end face of the rotors, and a housing cover arranged on the opposite side, the housing cover being configured cupshaped and the high-pressure port as well as the low-pressure port being integrated in the housing cover.

Background to the Invention With pumps of this type, the blades of the rotors engage each other without having any contact, so that a lubricate-free operation is made possible. Hence, there are manifold fields of application for such pumps. Due to the manifold application possibilities of these pumps, an optimization with respect to the size, the weight and the production costs is aimed at.

From US 4 057 375 there is known a positive-displacement pump comprising two blade wheels which rotate in synchronism and with opposite sense of rotation, and the blades of which, due to their meshing engagement, form distinct spaces with changeable volume during the rotary motion; in these spaces, a compressed flow medium is conveyed from the low-pressure side to the high-pressure side, the flow medium being conveyed in a direction perpendicular to the two axes.

Further, in GB 2 139 287 A there is disclosed a hydraulic pump comprising two toothed wheels being in meshing engagement, which are disposed in a chamber into the envelope of which open inlet and outlet channels. With these known pumps, the rotors S: 25 are supported on both sides, i.e. on each of the two axle ends. The pump chamber is limited on both end faces by a part of the housing cover. The suction and pressure channels open into the envelope of the pump chamber.

In EP 0 389 838 A2, which forms the most pertinent prior art, there is described a rotating piston pump in the form of a roots compressor having two rotors which are 30 arranged cantilevered on two axles being parallel to each other and which make possible the continuous conveying of various incompressible flow media. The rotors are disposed in a chamber which on the side of the gear box is limited by a flat plate through which the axles of the rotors are passed in a fluid-tight manner and on the side facing away from the gear box is limited by a housing cover in the envelope of 35 which are arranged guided radially to the outside connection ports for inlet and outlet.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Summary of the Invention According to an aspect of the present invention there is provided a pump for generating pressure or negative pressure, comprising a pump chamber which has a high-pressure port and a low-pressure port, two rotors having at least two blades and fitted to two parallel shafts in the pump chamber that are offset to each other wherein the parallel shafts define an axial direction, a drive arranged on an end face of the rotors, and a housing cover arranged on the opposite side, wherein the housing cover is configured cup-shaped and the high-pressure port as well as the low-pressure port is integrated in the housing cover, and wherein the housing cover has two openings, for the high-pressure port and the low-pressure port, which are each adjoined by one channel which is integrated in the body of the housing cover, characterized in that the openings are designed as axial openings in the inner wall of the housing cover delimiting the pump chamber on an end face and that the blade geometry of the rotors is designed for inner compression.

25 Through the invention there is made available a pump which has a space-saving and simple structure and allows to provide the low-pressure and high-pressure openings on the housing in an end face position.

This is achieved according to the invention in that the inner wall of the housing cover delimits the pump chamber on an end face and has two openings for the high- 30 pressure and the low-pressure port, and in that the openings are each adjoined by one *..*channel which is integrated in the body of the housing cover. One single component, namely the housing cover, has three functions: the limitation of the pump chamber on 2"the end face side, the circumferential wall of the pump chamber and accommodating the connection channels. The housing cover can be produced as a cast or shaped part in 35 an economical way.

Brief Description of Drawings Further features and advantages will be apparent from the following description of an advantageous embodiment and the drawing to which reference is mad and in which: Fig. 1 shows a side view of a pump assembly which is illustrated axially sectioned in the region of the pump section; Fig. 2 shows a side view of a housing cover; Fig. 3 shows a plan view of the housing cover; Fig. 4 shows a further side view of the housing cover; Fig. 5 shows a plan view of the inner side of the housing cover; and Fig. 6 shows a section along line VI-VI in Fig. Detailed Description of Preferred Embodiment The pump assembly shown in Fig. 1 has a drive in the form of an electric motor The latter is flange-mounted to the side of a fan hood 12. By means of a clutch 14, the electric motor 10 is connected with a fan wheel 16 within the fan hood 12. The fan hood 12 is put on a gear box 18. Two shafts 20, 22 that are parallel and offset to each other are supported on each of their ends in the gear box 18. Two shafts 20, 22 that are parallel and offset to each other are supported on each of their ends in the gear box 18.

The shaft 20 is arranged so as to be aligned with the axis of the electric motor 10 and is directly driven by it. A first spur-toothed wheel 20 is mounted on (Next text page 3) *o* -3the shaft 20, this first wheel being in meshing engagement with a second spurtoothed wheel 26 mounted on shaft 22.

On that ends of the shafts 20, 22 which are non-supported and facing away from the gear box 18, there is provided one two-blade rotor 28, 30 each. The blades of the rotors 28, 30 are claw-shaped and the geometry of which is designed for inner compression. The shafts 20, 22 in the gear box 18 run on ball bearings on both sides of the toothed wheels 24, 26, in particular on double-row angular ball bearings, as can be seen from Fig. 1. Thereby, the shafts 20, 22 get a firm guidance and support with respect to the cantilevered mount of the rotors.

The gear box 18 forms with its face facing the rotors 28, 30 a limiting wall on the end face of a pump chamber 32, which for the rest is limited by a cup-shaped housing cover 34 put on the gear box 18. With its flat inner wall, the housing cover 34 limits the pump chamber 32 on the side facing away from the gear box 18 and forms the circumferential wall of the pump chamber 32 by means of its envelope.

Integrated in the housing cover 34 are channels forming the high-pressure port and the low-pressure port of the pump. The design of these channels and connections is apparent from Figs. 2 to 6.

As can be seen in particular from Figs. 2 to 6, bulges 36, 38 are formed in the end face of the housing cover 34, through which are realized outer limiting walls of two channels 40, 42 integrated in the housing cover. Two openings 46, 48 are formed in the flat inner wall 44 of the housing cover 34. The channel 40 starts from opening 46. This channel has a first channel section which extends in parallelism to the inner wall 44, adjoining thereto a channel section which is inclined obliquely in the direction away from the inner wall and inclined outwardly, as well as a channel section adjoining thereto which extends outwardly and in parallelism to the inner wall 44, and opens out at the circumference of the housing cover 34 into a connection flange 50. The opening 48 is adjoined by channel 42 which likewise has a first channel section which extends in parallelism -4to the inner wall 44, a channel section adjoining thereto which is inclined obliquely outwardly towards the drive side, as well as a channel section again extending in parallelism to the inner wall 44, and opening out at the circumference of the housing cover 34 into a connection flange 52. The connection flanges 52 are situated on sides of the housing cover facing away from each other and are at different levels.

Due to the cantilevered support of the rotors 28, 30 there remains available, in the region of the free ends of the shafts 22, 24, a space for an optimum design of the channels 40, 42. The channels 40, 42 can be designed in particular with respect to optimum flow conditions and favorable connection conditions.

Claims

1. A pump for generating pressure or negative pressure, comprising a pump chamber which has a high-pressure port and a low-pressure port, two rotors having at least two blades and fitted to two parallel shafts in the pump chamber that are offset to each other wherein the parallel shafts define an axial direction, a drive arranged on an end face of the rotors, and a housing cover arranged on the opposite side, wherein the housing cover is configured cup-shaped and the high-pressure port as well as the low- pressure port is integrated in the housing cover, and wherein the housing cover has two openings, for the high-pressure port and the low-pressure port, which are each adjoined by one channel which is integrated in the body of the housing cover, characterized in that the openings are designed as axial openings in the inner wall of the housing cover delimiting the pump chamber on an end face and that the blade geometry of the rotors is designed for inner compression.

2. The pump according to claim 1, characterized in that at least one of the channels leads to the circumference of the housing cover and opens out there.

3. The pump according to claim 2, characterized in that the channel has a first channel section extending in parallelism to the inner wall of the housing cover, adjoining thereto a channel section which is inclined obliquely in the direction away from the inner wall and inclined outwardly, and adjoining thereto a channel section which opens out at the circumference of the housing cover and is parallel to the inner wall thereof

4. The pump according to any one of the preceding claims, characterized in that two connection flanges are formed on the circumference of the housing cover at two sides facing away from each other. 30

5. The pump according to claim 4, characterized in that the connection flanges are vertically offset to each other.

6. The pump according to any one of the preceding claims, characterized in that at least a substantial part of the circumferential wall of the pump chamber is formed by 35 the envelope of the housing cover.

7. The pump according to any one of the preceding claims, characterized in that the shafts are supported on one side, which is the side that faces the drive.

8. The pump according to any one of the preceding claims, characterized in that the shafts are each supported on both sides of a toothed wheel.

9. The pump according to any one of the preceding claims, characterized in that the axial opening for the high-pressure port and the axial opening of the low-pressure port have different sizes. The pump substantially as herein before described with reference to the accompanying figures. Dated this first day of May 2003 Werner Rietschle GmbH Co. KG Patent Attorneys for the Applicant: F B RICE CO *oo* *o• *i