GB2242708A

GB2242708A - Sliding-vane or swing-vane vacuum pump

Info

Publication number: GB2242708A
Application number: GB9106517A
Authority: GB
Inventors: Helmut Rossel; Martin Krucinski; Ulrich Flesch
Original assignee: Pierburg GmbH
Current assignee: Pierburg GmbH
Priority date: 1990-04-04
Filing date: 1991-03-27
Publication date: 1991-10-09
Anticipated expiration: 2011-03-27
Also published as: IT1246116B; ITRM910185A1; DE4010755A1; ITRM910185A0; GB2242708B; GB9106517D0; DE4010755C2; FR2660704B1; FR2660704A1

Abstract

Pumping cells are formed between vanes 5 of a rotor 4 which is driven eccentrically in a pumping chamber 3 to draw in air from an inlet port 8 connected to a reservoir or directly to a consumer of vacuum and deliver air to an exhaust port 9. In addition to the inlet port 8 there is provided at least one auxiliary inlet port 10 or 10' which is connected to a separate reservoir or consumer of vacuum and it is arranged that this auxiliary inlet port 10 or 10' does not come into communication with a pumping cell 6 or 7 until communication has been discontinued between the first inlet port 8 and that cell. Connection between the auxiliary port 10 or 10' and the cell 6 or 7 is effected by means of a control slot 11 or recess 12 of the rotor which during pump operation periodically uncovers the auxiliary inlet port. A plurality of servo mechanisms may be operated by one single-action vacuum pump. <IMAGE>

Description

1 1 ::i, -. 7 0 a 1 VANE-CELL OR SWING-VANE VACUUM PUMP The invention

relates to a vane-cell or swing-vane vacuum pump. Such vane- cell or swing-vane vacuum pumps are required for motor vehicles having vacuum operated servo mechanisms with a reservoir. In such systems pumping cells formed between vanes of a rotor which is driven eccentrically in a pumping chamber, exhaust air from an inlet port connected to the reservoir (or in some cases directly from a consumer of vacuum) and deliver air to an outlet by way of an exhaust port.

Vacuum pumps of this type (DE-OS 34 31719) are installed for example in motor vehicles, driven by their internal combustion engines, and such pumps are used to empty vacuum reservoirs which are often part of servo mechanisms such as, for exarnple, power braking or door locking systems which are operated by pressure differences created between the atmosphere and the reservoir. In some cases in addition to being used to evacuate a reservoir, the exhauster pump is also placed directly in communication with a consumer of vacuum or with a plurality of such consumers and/or reservoirs.

In order to exclude mutual interference between the servo mechanisms, exhaustion is effected by vacuum pumps having a delivery chamber connected to each reservoir or consumer. However, since such vacuum pumps are considerably expensive to construct, consideration has been directed towards how several servo mechanisms might be operated with only a single vacuum pump without mutual interference between said mechanisms.

According to the invention, in addition to the normal inlet port, there is provided at least one auxiliary inlet port which is connected to a separate reservoir (or consumer of vacuum) and it is arranged that this auxiliary inlet port does not come into communication with a given cell until all con-imunication has been discontinued between the first inlet port and that given cell.

2 Connection between the auxiliary port and the given cell is conveniently effected by means of a control slot or recess of the rotor which during pump operation periodically uncovers the auxiliary inlet port this otherwise being covered by a face of a rotor.

As a result a plurality of servo mechanisms may be operated with one single-action vacuum pump. And it can be ensured that the functioning of at least one mechanism is not disrupted by the functioning of a separate mechanism.

An embodiment of the invention is illustrated in the drawing and is described hereinafter.

The drawing shows purely diagrammatically a vacuum pump 1 comprising a housing 2 with a cylindrical recess 3, in which there is eccentrically disposed a rotor 4 fitted with swing vanes 5, which fit against the wall of the cylindrical recess 3. By this arrangement, pumping cells 6,7 are formed between the housing wall and the rotor vanes during rotation of the rotor for example by an internal combustion engine. The rotor having its centre indicated at x rotates in the direction of the arrow about an axis indicated at y which is at the centre of the recess 3.

As the rotor rotates, the cell 6 on the right hand enlarges and air is extracted from a reservoir or consumer (not shown) through an inlet port 8. As the cell 7 on the left contracts, air is delivered to an outlet port 9 which may lead into chambers of the internal combustion engine or the atmosphere. As the rotor 4 rotates the vanes 5 sweep past the ports 8 and 9 successively. As the vanes move past the outlet port 9, they move into recess 12 of the rotor 4. Thus far, said vacuum pump corresponds to prior art.

1 i 3 According to the invention, such a vacuum pump 1 is provided with at least one auxiliary inlet port 10 which is connected to a further reservoir or consumer (not shown). This auxiliary inlet port 10 is situated in the face of the cylindrical recess 3 and in one embodiment, it is covered by the face of the rotor 4, only being released when one or more control slots 11 of the rotor 4 passes by above it.

Instead of the illustrated control slots 11 cooperating with the auxiliary inlet port 10, the recesses 12 of the rotor 4 may be used successively to uncover an auxiliary inlet port 10' (shown by broken lines). In this case, advantageously, there may be disposed in the auxiliary inlet port 10', a one way valve which ensures that any pressure increase in cell 7 does not penetrate back into the reservoir or consumer with which the channel 10' connects.

The auxiliary inlet port 10 and the (or each) control slot 11 are so arranged that the auxiliary inlet channel 10 is not connected to a given cell 7 until the vane 5 defining the trailing end of that cell has moved past the inlet port 8. The partial vacuum prevailing in the cell 7 is then transmitted by the auxiliary inlet port 10 to the further reservoirs or consumers, exhausting air into the cell 7. Said air together with the air already previously delivered by way of inlet 8 from the first reservoir or consumer, is driven, upon further rotation of the rotor 4, to the outlet port 9, whence, for example, it is expelled into chambers of the internal combustion engine or to the atmosphere. The pressure increase building up in the left hand cell 7 has no effect upon the further reservoir or consumer since the auxiliary inlet channel 10 is closed again when the control slot 11 travels out of the region where it uncovers the auxiliary inlet channel 10.

The invention is not restricted to the embodiment illustrated but also includes constructions having a plurality of further inlet channels which may be successively released and function in the same manner as in the illustrated embodiment. A construction having retractable vanes (vanecell pump) instead of pivotal swinging vanes as illustrated, is also feasible.

Operation The illustrated vacuum pump 1, on rotation of the rotor 4, forms on the right hand side of the drawing a cell 6, which increases in size and so forms a low pressure region or vacuum, up to the point when the swinging vane 5 passes the inlet port 8, so that air is extracted from a first reservoir (not shown) or other consumer. This air is moved ahead of vane 5 into the left hand cell 7 which contracts to expel the air (or a part of it) through the exhaust port 9. Before the cell 6 has reached its maximum volume, the inlet port 8 has already been passed by the vane 5, and from this point, as is shown in the drawing, the auxiliary inlet port 10 is uncovered by the control slot 11 of the rotor 4 to allow air to be extracted from a further reservoir or consumer (that is separate from the reservoir or consumer which is evacuated or exhausted by way of inlet port 8).

Thus extraction of air from a first reservoir or consumer is not affected by the subsequent extraction of air from the further reservoir or consumer. For this reason, the first reservoir should be associated with a servo mechanism with a safety function, while the further reservoir should be associated with a servo, mechanism or mechanisms not affecting driving safety, e.g. door locking system etc.

i i 1 I 1 1

Claims

1.

A rotary vane or a swing-vane vacuum pump having an eccentric rotor equipped with swinging or sliding vanes which during operation of the pump define between them pumping cells, and the pump having an inlet and an outlet port, the inlet port being connected to a vacuum reservoir (or other consumer of vacuum) and coming into connection with the pumping cells as they are formed between the pump vanes during operation of the pump, as each cell enlarges and before it has reached its maximum volume, while the outlet port is brought into communication with each cell as it is contracting; characterised in that in addition to said already mentioned inlet port (8), there is provided at least one auxiliary inlet port (10 or 10') which is connected to a further reservoir (or other consumer of vacuum), said auxiliary inlet port only being brought into communication with a pumping cell, when communication between that cell and the first mentioned inlet port (8) has been discontinued.

2. A pump according to claim 1, and in which communication between the auxiliary inlet (10, 10) and a pumping cell (7) is effected by means of a control slot or recess (11, 12) of the rotor (4) which uncovers the auxiliary inlet channel (10, 10) periodically during operation of the pump.

3. A vacuum pump substantially as hereinbefore described with reference to the accompanying drawing.

Published 1991 at The Patent Office. Concept House. Cardiff Road. Newport. Gwent NP9 I RH. Further copies maybe obtained from Sales Branch. Unit 6. Nine Mile Point. CA-mfelinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques lid. St Mary Cray. Kent.