WO2005093217A1 - Monovane vacuum pump - Google Patents

Monovane vacuum pump Download PDF

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Publication number
WO2005093217A1
WO2005093217A1 PCT/GB2005/001214 GB2005001214W WO2005093217A1 WO 2005093217 A1 WO2005093217 A1 WO 2005093217A1 GB 2005001214 W GB2005001214 W GB 2005001214W WO 2005093217 A1 WO2005093217 A1 WO 2005093217A1
Authority
WO
WIPO (PCT)
Prior art keywords
rotor
casing
vane
vacuum pump
wall
Prior art date
Application number
PCT/GB2005/001214
Other languages
French (fr)
Inventor
David Heaps
Martyn Taylor
Original Assignee
Wabco Automotive Uk Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wabco Automotive Uk Limited filed Critical Wabco Automotive Uk Limited
Publication of WO2005093217A1 publication Critical patent/WO2005093217A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/30—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
    • F04C18/34—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members
    • F04C18/344—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member
    • F04C18/3441—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member the inner and outer member being in contact along one line or continuous surface substantially parallel to the axis of rotation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C21/00—Component parts, details or accessories not provided for in groups F01C1/00 - F01C20/00
    • F01C21/10—Outer members for co-operation with rotary pistons; Casings
    • F01C21/104—Stators; Members defining the outer boundaries of the working chamber
    • F01C21/106—Stators; Members defining the outer boundaries of the working chamber with a radial surface, e.g. cam rings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/02—Lubrication; Lubricant separation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2220/00—Application
    • F04C2220/10—Vacuum

Definitions

  • the present invention relates to vacuum pumps and in particular sliding vane vacuum pumps for vehicle braking systems.
  • a sliding vane vacuum pump typically comprises a casing defining a cavity having mounted therein a rotor and an elongate vane.
  • the cavity is provided with an inlet and an outlet, while the vane is slidably mounted in a slot of the rotor.
  • the dimensions of the vane, position of the rotor and shape of the cavity are such that each end of the vane is held in close proximity to a wall of the cavity at all rotational positions of the rotor. Rotation of the rotor causes the vane to move within the cavity and create a pressure differential thereacross which is exploited to draw air through the inlet and subsequently out through the outlet.
  • the tips of the vane are required, in use, to be disposed very close to the cavity wall. Adequate sealing between the tips and the cavity wall is achieved by the presence of oil within the cavity which, in use, resides in the space between the tips and the wall.
  • a vacuum pump comprising a casing defining a chamber, the chamber having a suction port, a vent port, a rotor rotatably mounted in the chamber and a vane slidably supported by said rotor, the casing being provided with a recess to receive lubricant entrained by the vane.
  • the recess is advantageously provided in the casing adjacent the rotor and slightly ahead, in the direction of rotation of the rotor, of the position at which the casing is closest to the rotor. This is to say that during rotation of the rotor and vane, the vane encounters the recess before encountering the position at which the casing is closest to the rotor. It will thus be appreciated that lubricant is received in the recess before the rotor passes the above mentioned position where the casing is closest to the rotor. Lubricant received in the recess is able to flow around the tip of the rotor and hence is not conveyed through the gap between the rotor and the casing.
  • the recess may comprise a conduit of the casing.
  • the conduit is provided with an inlet and an outlet, with the inlet provided in the casing adjacent the rotor and slightly ahead, in the direction of rotation of the rotor, of the position at which the casing is closest to the rotor.
  • the outlet is positioned away from rotor such that lubricant entering the conduit is conducted away from the rotor.
  • the conduit may be provided with a non-return arrangement so as to ensure that lubricant can only flow unidirectional from the inlet to the outlet.
  • Figure 1 shows a plan view of a vacuum pump according to a first embodiment the present invention.
  • Figure 2 shows a portion of a cavity wall of a vacuum pump according to a second aspect of the present invention.
  • a vacuum pump for the braking system of a vehicle generally designated 10.
  • the pump 10 comprises a casing 12 having therein a cavity 14.
  • the cavity 14 is enclosed by a plate which is omitted for the sake of clarity.
  • the cavity 14 is defined by the plate, a base 15 of the casing 12 and a peripheral wall 17 of the casing 12.
  • the vane 18 is slidably mounted in a slot 20 of the rotor 16.
  • the casing 12 is further provided with an inlet 22 and an outlet (not shown) which are in fluid communication with the cavity 14.
  • the rotor 16 extends through the casing 12, via appropriate bearing and sealing means, to a drive formation adapted to mate with a driver, for example a drive shaft.
  • the casing 12 is further provided with a lubricant conduit (not shown) which permits a lubricant such as oil to be introduced into the cavity 14.
  • the tip member 24 comprises a projection 26, which is received in a corresponding recess 28 of the vane 18, and a crown portion 30 which overlies the end of the vane 18.
  • the crown portion 30 has a rounded outer surface 32 which, at its widest point, is substantially the same width as the vane 18. It will thus be appreciated that the outer surface 32 of the tip merges substantially seamlessly with the vane 18.
  • lubricant 34 is entrained by, and pushed ahead of, the tip members 24 during rotation of the vane 18. Problems can arise when the vane tip member 24 is rotated through the small gap 34 where rotor 16 is closest to the wall of the cavity 14. The lubricant entrained by the vane 18 in being forced through this gap 34 may apply a braking force to the rotor 16 which in turn may exert unwanted forces on this and other pump components.
  • the casing 12 is provided with a blind recess 36 which is positioned at the start of the gap 34 in the direction of rotation of the rotor 16.
  • the recess 36 is provided in a portion of the wall 17 of the casing 12 over which the end face or outer surface 32 of the tip members 24 sweep.
  • lubricant entrained with the vane 18 is forced into the recess 36 and flows around the rotor tip member 24 rather than being swept through the gap 34. Unwanted loading of the pump components as a result of the increase in hydrodynamic pressure of the lubricant as it is forced through the gap 34 is thus avoided.
  • the length of the recess 36 is substantially equal to the thickness of the vane 18. It will be appreciated that the length of the recess 36 may be greater than the thickness of the vane 18.
  • the width of the recess is less than the depth of the vane 18 so as to ensure that the tip members 24 are not able to enter the recess 36 and thus become damaged by contact with the edges thereof.
  • the recess 36 is advantageously provided in the wall 17 casing 12 along the interface between the wall 17 and the base 15.
  • An alternative embodiment of the present invention is shown in figure 2.
  • the casing is provided with a conduit 38 having an inlet 40, an outlet 42 and a non-return means 44.
  • Lubricant entrained with the vane 18 is able to enter the conduit 38 through the inlet 40, but is prevented from entering via the outlet 42 by the presence of the non-return means 44. As additional lubricant is forced into the inlet 40 by successive passes of the vane 18, the lubricant is forced out of the outlet 42 behind the vane 18.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Rotary Pumps (AREA)

Abstract

A vacuum pump (10) comprises a casing (12) defining a chamber (14), the chamber (14) having a suction port (22), a vent port, a rotor (16) rotatably mounted in the chamber (14) and a vane (18) slidably supported by said rotor (16), the casing (12) being provided with a recess (36) in a peripheral wall (17) thereof to receive lubricant entrained by the vane (18).

Description

MONOVANE VACUUM PUMP
The present invention relates to vacuum pumps and in particular sliding vane vacuum pumps for vehicle braking systems.
A sliding vane vacuum pump typically comprises a casing defining a cavity having mounted therein a rotor and an elongate vane. The cavity is provided with an inlet and an outlet, while the vane is slidably mounted in a slot of the rotor. The dimensions of the vane, position of the rotor and shape of the cavity are such that each end of the vane is held in close proximity to a wall of the cavity at all rotational positions of the rotor. Rotation of the rotor causes the vane to move within the cavity and create a pressure differential thereacross which is exploited to draw air through the inlet and subsequently out through the outlet.
In order to create the required pressure differential the tips of the vane are required, in use, to be disposed very close to the cavity wall. Adequate sealing between the tips and the cavity wall is achieved by the presence of oil within the cavity which, in use, resides in the space between the tips and the wall.
According to the present invention there is provided a vacuum pump comprising a casing defining a chamber, the chamber having a suction port, a vent port, a rotor rotatably mounted in the chamber and a vane slidably supported by said rotor, the casing being provided with a recess to receive lubricant entrained by the vane.
The recess is advantageously provided in the casing adjacent the rotor and slightly ahead, in the direction of rotation of the rotor, of the position at which the casing is closest to the rotor. This is to say that during rotation of the rotor and vane, the vane encounters the recess before encountering the position at which the casing is closest to the rotor. It will thus be appreciated that lubricant is received in the recess before the rotor passes the above mentioned position where the casing is closest to the rotor. Lubricant received in the recess is able to flow around the tip of the rotor and hence is not conveyed through the gap between the rotor and the casing.
The recess may comprise a conduit of the casing. In such an embodiment the conduit is provided with an inlet and an outlet, with the inlet provided in the casing adjacent the rotor and slightly ahead, in the direction of rotation of the rotor, of the position at which the casing is closest to the rotor. The outlet is positioned away from rotor such that lubricant entering the conduit is conducted away from the rotor. The conduit may be provided with a non-return arrangement so as to ensure that lubricant can only flow unidirectional from the inlet to the outlet.
Embodiments of the present invention will now be described with reference to the accompanying drawings in which:
Figure 1 shows a plan view of a vacuum pump according to a first embodiment the present invention; and
Figure 2 shows a portion of a cavity wall of a vacuum pump according to a second aspect of the present invention.
Referring to figure 1 there is shown a vacuum pump for the braking system of a vehicle generally designated 10. The pump 10 comprises a casing 12 having therein a cavity 14. In use, the cavity 14 is enclosed by a plate which is omitted for the sake of clarity. The cavity 14 is defined by the plate, a base 15 of the casing 12 and a peripheral wall 17 of the casing 12. Within the cavity 14 there is provided a rotor 16 and a vane 18. The vane 18 is slidably mounted in a slot 20 of the rotor 16. The casing 12 is further provided with an inlet 22 and an outlet (not shown) which are in fluid communication with the cavity 14. The rotor 16 extends through the casing 12, via appropriate bearing and sealing means, to a drive formation adapted to mate with a driver, for example a drive shaft. The casing 12 is further provided with a lubricant conduit (not shown) which permits a lubricant such as oil to be introduced into the cavity 14.
At each opposing end of the vane 18 there is provided a separate tip member 24. The tip member 24 comprises a projection 26, which is received in a corresponding recess 28 of the vane 18, and a crown portion 30 which overlies the end of the vane 18. The crown portion 30 has a rounded outer surface 32 which, at its widest point, is substantially the same width as the vane 18. It will thus be appreciated that the outer surface 32 of the tip merges substantially seamlessly with the vane 18.
The introduction of lubricant into the cavity 14 is required so as to ensure that adequate sealing between the tip members 24 and the wall defining the cavity 14. In use, lubricant 34 is entrained by, and pushed ahead of, the tip members 24 during rotation of the vane 18. Problems can arise when the vane tip member 24 is rotated through the small gap 34 where rotor 16 is closest to the wall of the cavity 14. The lubricant entrained by the vane 18 in being forced through this gap 34 may apply a braking force to the rotor 16 which in turn may exert unwanted forces on this and other pump components.
In order to alleviate this problem the casing 12 is provided with a blind recess 36 which is positioned at the start of the gap 34 in the direction of rotation of the rotor 16. The recess 36 is provided in a portion of the wall 17 of the casing 12 over which the end face or outer surface 32 of the tip members 24 sweep. In use, lubricant entrained with the vane 18 is forced into the recess 36 and flows around the rotor tip member 24 rather than being swept through the gap 34. Unwanted loading of the pump components as a result of the increase in hydrodynamic pressure of the lubricant as it is forced through the gap 34 is thus avoided.
In the embodiment shown the length of the recess 36 is substantially equal to the thickness of the vane 18. It will be appreciated that the length of the recess 36 may be greater than the thickness of the vane 18. The width of the recess is less than the depth of the vane 18 so as to ensure that the tip members 24 are not able to enter the recess 36 and thus become damaged by contact with the edges thereof. The recess 36 is advantageously provided in the wall 17 casing 12 along the interface between the wall 17 and the base 15. An alternative embodiment of the present invention is shown in figure 2. Here the casing is provided with a conduit 38 having an inlet 40, an outlet 42 and a non-return means 44. Lubricant entrained with the vane 18 is able to enter the conduit 38 through the inlet 40, but is prevented from entering via the outlet 42 by the presence of the non-return means 44. As additional lubricant is forced into the inlet 40 by successive passes of the vane 18, the lubricant is forced out of the outlet 42 behind the vane 18.

Claims

Claims
1. A vacuum pump comprising a casing defining a chamber, the chamber having a suction port, a vent port, a rotor rotatably mounted in the chamber and a vane slidably supported by said rotor, the casing being provided with a recess in a peripheral wall thereof to receive lubricant entrained by the vane.
2. A vacuum pump as claimed in claim 1 wherein the recess is provided in the wall of the casing adjacent the rotor and slightly ahead, in the direction of rotation of the rotor, of the position at which the wall of the casing is closest to the rotor.
3. A vacuum pump as claimed in claim 1 or claim 2 wherein the recess is provided in the wall of the wall of the casing at the interface of the wall with an end wall of the chamber.
4. A vacuum pump as claimed in any preceding claim wherein the recess comprises a conduit in the wall of the casing.
5. A vacuum pump as claimed in claim 4 wherein the conduit is provided with an inlet and an outlet, with the inlet provided in the casing adjacent the rotor and slightly ahead, in the direction of rotation of the rotor, of the position at which the casing is closest to the rotor, and the outlet is positioned away from rotor such that lubricant entering the conduit is conducted away from the rotor.
6. A vacuum pump as claimed in claim 4 or claim 5 wherein the conduit is provided with a non-return arrangement so as to ensure that lubricant can only flow unidirectional from the inlet to the outlet.
PCT/GB2005/001214 2004-03-26 2005-03-24 Monovane vacuum pump WO2005093217A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0406897.9 2004-03-26
GB0406897A GB0406897D0 (en) 2004-03-26 2004-03-26 Vacuum pump oil pressure relief

Publications (1)

Publication Number Publication Date
WO2005093217A1 true WO2005093217A1 (en) 2005-10-06

Family

ID=32188806

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2005/001214 WO2005093217A1 (en) 2004-03-26 2005-03-24 Monovane vacuum pump

Country Status (2)

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GB (1) GB0406897D0 (en)
WO (1) WO2005093217A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2677118A1 (en) * 2012-06-20 2013-12-25 Pierburg Pump Technology GmbH Automotive volumetric vacuum pump

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3817665A (en) * 1973-04-20 1974-06-18 Reliance Electric Co Hydraulic pump or motor
JPS5424307A (en) * 1977-07-26 1979-02-23 Sanwa Seiki Mfg Co Ltd Vacuum pump
DE2945488A1 (en) * 1979-11-10 1981-05-21 Barmag Barmer Maschf Vacuum pump for vehicle brakes - has rotor of sintered alloyed aluminium for light weight
US4557678A (en) * 1983-06-21 1985-12-10 Mitsubishi Denki Kabushiki Kaisha Pump device
JPH02163487A (en) * 1988-12-16 1990-06-22 Hitachi Ltd Rotary compressor
FR2640699A1 (en) * 1988-12-21 1990-06-22 Bar Ag Ag Vane-type vacuum pump
US5779463A (en) * 1994-07-16 1998-07-14 Pierburg Ag Rotary piston pump having a slide valve driven by a rotor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3817665A (en) * 1973-04-20 1974-06-18 Reliance Electric Co Hydraulic pump or motor
JPS5424307A (en) * 1977-07-26 1979-02-23 Sanwa Seiki Mfg Co Ltd Vacuum pump
DE2945488A1 (en) * 1979-11-10 1981-05-21 Barmag Barmer Maschf Vacuum pump for vehicle brakes - has rotor of sintered alloyed aluminium for light weight
US4557678A (en) * 1983-06-21 1985-12-10 Mitsubishi Denki Kabushiki Kaisha Pump device
JPH02163487A (en) * 1988-12-16 1990-06-22 Hitachi Ltd Rotary compressor
FR2640699A1 (en) * 1988-12-21 1990-06-22 Bar Ag Ag Vane-type vacuum pump
US5779463A (en) * 1994-07-16 1998-07-14 Pierburg Ag Rotary piston pump having a slide valve driven by a rotor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 014, no. 418 (M - 1022) 10 September 1990 (1990-09-10) *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2677118A1 (en) * 2012-06-20 2013-12-25 Pierburg Pump Technology GmbH Automotive volumetric vacuum pump
WO2013189931A3 (en) * 2012-06-20 2014-05-15 Pierburg Pump Technology Gmbh Automotive volumetric vacuum pump with an oil discharge channel
CN104395557A (en) * 2012-06-20 2015-03-04 皮尔伯格泵技术有限责任公司 Automotive volumetric vacuum pump with an oil discharge channel
US9366256B2 (en) 2012-06-20 2016-06-14 Pierburg Pump Technology Gmbh Automotive volumetric vacuum pump
CN104395557B (en) * 2012-06-20 2017-03-01 皮尔伯格泵技术有限责任公司 There is the automobile displacement pump of oily discharge-channel

Also Published As

Publication number Publication date
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