U.S. patent application number 15/578254 was filed with the patent office on 2018-06-07 for automotive vacuum pump.
This patent application is currently assigned to PIERBURG PUMP TECHNOLOGY GMBH. The applicant listed for this patent is PIERBURG PUMP TECHNOLOGY GMBH. Invention is credited to CARLO PACHETTI, GIORGIO PERONI, MICHAEL ROMBACH, RAFFAELE SQUARCINI.
Application Number | 20180156218 15/578254 |
Document ID | / |
Family ID | 53298359 |
Filed Date | 2018-06-07 |
United States Patent
Application |
20180156218 |
Kind Code |
A1 |
PERONI; GIORGIO ; et
al. |
June 7, 2018 |
AUTOMOTIVE VACUUM PUMP
Abstract
An automotive vacuum pump includes a housing arrangement which
encloses a pumping chamber and which rotatably supports a pump
rotor having a rotor body with a bearing section and a vane
section. The vane section of the rotor body has a vane slit. A
slidable pump vane is supported in the vane slit. The slidable pump
vane separates the pumping chamber into a plurality of rotating
pumping compartments. The housing arrangement has a pumping chamber
gas inlet opening and a pumping chamber gas outlet opening. The
rotor body further has a separate oil outlet opening which is open
to the pumping chamber
Inventors: |
PERONI; GIORGIO; (PISA,
IT) ; SQUARCINI; RAFFAELE; (LIVORNO, IT) ;
ROMBACH; MICHAEL; (NEUSS, DE) ; PACHETTI; CARLO;
(CASCINA, PISA, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PIERBURG PUMP TECHNOLOGY GMBH |
NEUSS |
|
DE |
|
|
Assignee: |
PIERBURG PUMP TECHNOLOGY
GMBH
NEUSS
DE
|
Family ID: |
53298359 |
Appl. No.: |
15/578254 |
Filed: |
June 2, 2015 |
PCT Filed: |
June 2, 2015 |
PCT NO: |
PCT/EP2015/062285 |
371 Date: |
November 30, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 2220/10 20130101;
F04C 29/028 20130101; F04C 2240/10 20130101; F04C 25/02 20130101;
F04C 2240/20 20130101; F04C 18/3441 20130101 |
International
Class: |
F04C 29/02 20060101
F04C029/02; F04C 18/344 20060101 F04C018/344 |
Claims
1-8. (canceled)
9. An automotive vacuum pump comprising: a housing arrangement
configured to enclose a pumping chamber and to rotatably support a
pump rotor comprising a rotor body which comprises a bearing
section and a vane section, wherein, the vane section of the rotor
body comprises a vane slit, a slidable pump vane is supported in
the vane slit, the slidable pump vane being configured to separate
the pumping chamber into a plurality of rotating pumping
compartments, the housing arrangement comprises a pumping chamber
gas inlet opening and a pumping chamber gas outlet opening, and the
rotor body further comprises a separate oil outlet opening which is
open to the pumping chamber.
10. The automotive vacuum pump as recited in claim 9, wherein, the
rotor body further comprises a longitudinal cylindrical vane
section, and the separate oil outlet opening is arranged in the
longitudinal cylindrical vane section of the rotor body.
11. The automotive vacuum pump as recited in claim 9, wherein, the
pumping chamber is covered by two front end walls which are each
arranged to lie in a radial plane, and the separate oil outlet
opening is arranged adjacent to one of the two front end walls.
12. The automotive vacuum pump as recited in claim 9, wherein, the
separate oil outlet opening is arranged in a lagging third or in a
lagging fourth of a respective rotating pumping compartment.
13. The automotive vacuum pump as recited in claim 9, further
comprising: a gas-tight commutation sector arranged between the
pumping chamber gas outlet opening and the pumping chamber gas
inlet opening, the gas-tight commutation sector comprising a
commutation sector angle, wherein, the separate oil outlet opening
comprises a separate oil outlet opening angle, the commutation
sector angle is larger than the separate oil outlet opening angle,
and each of the commutation sector angle and the separate oil
outlet opening angle are seen from a center of the rotor body
perpendicular to an axis of rotation of the rotor body.
14. The automotive vacuum pump as recited in claim 9, wherein, the
pump rotor further comprises a coupling structure arranged at an
axial coupling end of the rotor body, and the rotor body further
comprises an oil duct which fluidically connects the separate oil
outlet opening to the axial coupling end.
15. The automotive vacuum pump as recited in claim 14, wherein, the
axial coupling end comprises an oil discharge opening which is
fluidically connected to the separate oil outlet opening, and the
oil discharge opening comprises a check-valve.
16. The automotive vacuum pump as recited in claim 9, wherein, one
slidable pump vane comprising one vane body is supported in the
vane slit which is configured to radially penetrate the rotor body,
and the rotor body comprises two separate oil outlet openings, one
of the separate oil outlet openings being arranged in each rotating
pumping compartment.
Description
CROSS REFERENCE TO PRIOR APPLICATIONS
[0001] This application is a U.S. National Phase application under
35 U.S.C. .sctn. 371 of International Application No.
PCT/EP2015/062285, filed on Jun. 2, 2015. The International
Application was published in English on Dec. 8, 2016 as WO
2016/192782 A1 under PCT Article 21(2).
FIELD
[0002] The present invention is directed to an automotive vacuum
pump which is lubricated with oil. The present invention can, for
example, be directed to a mechanical automotive vacuum pump which
is mechanically driven by an internal combustion engine.
BACKGROUND
[0003] An automotive vacuum pump is provided with a housing
arrangement which encloses a pumping chamber and rotatably supports
a pump rotor with a pump rotor body. The pump rotor body can be
separated in axial direction into two functional sections, namely,
a bearing section and a vane section. In the bearing section, the
rotor body is radially supported rotatably at the pump housing
arrangement. In the vane section, the rotor body is provided with
at least one vane slit wherein at least one slidable pump vane is
slidably supported. The pump vane or the pump vanes separate the
pumping chamber into several rotating pumping compartments.
[0004] The housing arrangement is provided with a pumping chamber
gas inlet opening through which gas flows into the pumping chamber,
and with a pumping chamber gas outlet opening through which
compressed gas leaves the pumping chamber. The gas inlet opening
and the gas outlet opening are in most cases provided in a pump
chamber front end wall which lies in a radial plane perpendicular
to the rotational axis of the pump rotor.
[0005] The vacuum pump is supplied with pressurized oil which is
used to improve the pneumatic performance and, in case of a
mechanical vacuum pump, is also used to lubricate the mechanical
coupling of the vacuum pump. A particular amount of oil is supplied
into the pumping chamber so that not only gas, but also oil, must
be discharged from the pumping chamber to avoid extensive
vibrations and a deformation of the pump vane in the final
discharge phase of the respective pumping compartment.
[0006] The oil is discharged together with the gas through one
single combined gas and oil outlet opening in state-of-the-art
vacuum pumps. It is also known to provide a separate oil outlet
opening in a front end wall of the housing arrangement. The
separate oil outlet opening is arranged behind the gas outlet
opening, as seen in the direction of rotation. The oil outlet
opening is therefore relatively small so that the flow and pressure
conditions during the oil discharge phase can be dramatic, in
particular at high rotational speed.
SUMMARY
[0007] An aspect of the present invention is to provide an
automotive vacuum pump with smoother oil discharge
characteristics.
[0008] In an embodiment, the present invention provides an
automotive vacuum pump which includes a housing arrangement which
is configured to enclose a pumping chamber and to rotatably support
a pump rotor comprising a rotor body which comprises a bearing
section and a vane section. The vane section of the rotor body
comprises a vane slit. A slidable pump vane is supported in the
vane slit. The slidable pump vane is configured to separate the
pumping chamber into a plurality of rotating pumping compartments.
The housing arrangement comprises a pumping chamber gas inlet
opening and a pumping chamber gas outlet opening. The rotor body
further comprises a separate oil outlet opening which is open to
the pumping chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention is described in greater detail below
on the basis of embodiments and of the drawings in which:
[0010] FIG. 1 shows a cross-section of a mechanical automotive
vacuum pump including a pump rotor with two oil outlet
openings;
[0011] FIG. 2 shows a longitudinal section of the vacuum pump of
FIG. 1;
[0012] FIG. 3 shows a longitudinal section of the pump rotor of the
vacuum pump of FIGS. 1 and 2; and
[0013] FIG. 4 shows a plan view of the bearing section including a
coupling structure of the pump rotor of the vacuum pump of FIGS. 1
and 2.
DETAILED DESCRIPTION
[0014] The automotive vacuum pump according to the present
invention is provided with a rotor body which is provided with a
separate oil outlet opening which is open to the pumping chamber
and through which the oil is discharged from the rotating pumping
compartment in the final compression phase of the respective
pumping compartment. The oil outlet opening is not provided in a
static housing wall, but is co-rotatably provided at the rotor
body. The gas outlet opening can, for example, be arranged at a
static side wall of the pump housing arrangement. The gas outlet
opening and the separate oil outlet opening are therefore no longer
in conflict with respect to the available surface. The opening
angle of the oil outlet opening can be increased significantly
since the oil outlet opening is not provided at the housing. Since
the opening angle of the oil outlet opening is increased, there is
more time to discharge the oil from the rotating pumping
compartment in the final compression phase of the pumping
compartment. The oil discharge process is therefore smoother, in
particular at a high rotational speed of the pump rotor. This leads
to decreased noise, decreased vibration, and a decreased wear out
of the mechanical components.
[0015] The gas openings are in fluidic connection with a pump gas
inlet and with a pump gas outlet, respectively. It is not excluded
that oil flows through a gas opening. The oil outlet opening has
the main function to lead oil to a separate oil outlet, not to the
pump gas outlet. But it cannot be excluded that gas is also
discharged through the oil outlet opening.
[0016] In an embodiment of the present invention, the oil outlet
opening can, for example, be provided in the longitudinal
cylindrical vane section of the rotor body. The oil outlet opening
is not provided in the bearing section of the rotor body. The
complete oil outlet opening can, for example, be provided in the
cylindrical vane section of the rotor body.
[0017] In an embodiment of the present invention, the pumping
chamber can, for example, be covered by two front end walls both
lying in a radial plane so that the end walls are lying in a plane
perpendicular to the rotational axis of the pump rotor. The oil
outlet opening is provided adjacent to one end wall, and is in
particular provided adjacent to the front end wall which lies below
the other end wall, with respect to the vector of gravitation, when
the vacuum pump is mounted in an automobile. The oil outlet opening
can, for example, be placed as close as possible to the bottom
plane of the rotor to minimize the pressure drop all along the
rotor's internal duct. The oil outlet opening can, for example, be
arranged at the lowest point of the pumping chamber in the final
phase of the compression interval of the respective pumping
compartment. This arrangement of the oil outlet opening provides
that the oil volume which is accumulated at the lowest
gravitational location within the rotating pumping compartment can
directly be discharged via the oil outlet opening when the rotating
oil outlet opening arrives at the final compression phase of the
respective pumping compartment.
[0018] In an embodiment of the present invention, the oil outlet
opening can, for example, be provided in the lagging third of the
respective pumping compartment, for example, in the lagging fourth
of the respective pumping compartment. The oil outlet opening
therefore arrives at the final compression zone right before the
vane head arrives at the commutation sector which is the
liquid-tight sector between the gas outlet opening and the gas
inlet opening, as seen in the direction of rotation. In other
words, the oil outlet opening is arranged in that sector of the
respective pumping compartment which arrives at last at the
gas-tight commutation sector.
[0019] In an embodiment of the present invention, the opening angle
of the oil outlet opening can, for example, be smaller than the
angle of the gas-tight commutation sector between the gas outlet
opening and the gas inlet opening so that the oil outlet opening
cannot define a fluidic bypass with respect to the commutation
sector. The opening angle of the white outlet opening is an angle
lying in a radial plane and with the sector center lying in the
rotational axis of the pump rotor.
[0020] In an embodiment of the present invention, the pump rotor
can, for example, be provided with a coupling structure at one
axial coupling end of the rotor body. The coupling structure can,
for example, be provided at one axial coupling end which is defined
by the bearing section of the rotor body. The rotor body is
provided with an oil conduct which fluidically connects the oil
outlet opening to the axial coupling end. As a result, the coupling
structure is directly lubricated with the oil which is discharged
via the oil outlet opening.
[0021] In an embodiment of the present invention, the oil discharge
opening can, for example, be provided with a check-valve so that a
backflow of the oil in a direction from the axial coupling
structure and back to the oil outlet opening is avoided.
[0022] In an embodiment of the present invention, the vacuum pump
can, for example, be provided as a single-vane pump with one single
pump vane which can have two vane parts which are slidable to each
other. The single vane is supported by the single vane slit which
radially penetrates the rotor body. At least two oil outlet
openings are provided at the rotor body, one oil outlet opening in
each pumping compartment.
[0023] An embodiment of the present invention is described below
under reference to the drawings.
[0024] The drawings show a mechanical automotive vacuum pump 10
which provides an absolute pressure of below 100 mbar for
supplying, for example, a pneumatic breaking force device with low
pressure. The vacuum pump 10 is mechanically driven by an
automotive engine, for example, by an internal combustion
engine.
[0025] The vacuum pump 10 comprises a static housing arrangement 12
which supports and substantially houses a rotatable pump rotor 14.
The housing arrangement 12 comprises a complex and pot-shaped
housing main body 11 for radially enclosing and rotatably
supporting the pump rotor 14 and comprises a separate housing cover
lid 13 for axially closing one axial end of the housing arrangement
12.
[0026] The pump rotor 14 comprises a plastic pump rotor body 30
with a substantially cylindrical and stepless outer surface over
the entire axial length of the pump rotor body 30. The pump rotor
body 30 is axially provided with two functional partitions, namely,
the vane section 16 with a vane slit 32, and the bearing section 18
where the pump rotor body 30 is rotatably supported at the housing
body 11 by a frictional bearing. The vane slit 32 supports a
radially shiftable pump vane 33 which is defined by one single vane
body 34 which co-rotates with the pump rotor body 30.
[0027] The housing arrangement 12, which is defined by the housing
body 11 and the housing lid 13, encloses a pumping chamber 17
wherein the pump vane 33 rotates. The housing lid 13 defines one
axial front end wall 64, and a ring-like portion of the housing
body 11 defines a ring-like front end wall 62 of the pumping
chamber 17. The pump vane 33 separates the pumping chamber 17 into
two pumping compartments 171, 172 which rotate when the pump rotor
14 rotates.
[0028] In the bearing section 18, the pump rotor body 30 is
provided with a cylindrical bearing surface which defines a radial
friction bearing together with a corresponding cylindrical bearing
surface of the housing main body 11. The pump rotor 14, in this
embodiment, is supported by only one radial friction bearing so
that the body of the pump rotor 14 is supported cantilevered. The
bearing-sided axial coupling end 72 of the pump rotor 14 is
provided with a bearing ring surface which is axially supported by
a corresponding axial bearing ring surface defined by the housing
main body 11. The two bearing ring surfaces together define an
axial friction bearing. As shown in FIG. 4, the bearing-sided
coupling end 72 of the pump rotor 14 is provided with a coupling
structure 70 for coupling a corresponding coupling structure of a
pump drive. The other front end of the pump rotor body 30 is
axially supported by the housing lid 13.
[0029] The bearing-sided ring-like front end wall 62 is provided
with a sickle-shaped gas inlet opening 26 and with a sickle-shaped
gas outlet opening 22. The gas inlet opening 26 is fluidically
connected to a pump inlet 28 via a gas inlet channel 27. The gas
outlet channel is fluidically connected to a pump outlet via a gas
outlet channel 23. The gas inlet channel 27 and the gas outlet
channel 23 are defined as bores in a ring body section 20 of the
housing body 11.
[0030] Seen in a circumferential direction, a commutation sector 60
is defined between the gas outlet opening 22 and the gas inlet
opening 26 (see FIG. 1). In the commutation sector 60, the pump
rotor body 30 is arranged directly adjacent to the circumferential
wall 80 of the housing body 11 so that the commutation sector 60
defines a gas-tight section, thereby avoiding a flow-back of
compressed gas. The commutation width of the commutation sector 60,
seen in a circumferential direction, is equal or larger than the
thickness of the vane body 34 or of the vane slit 32.
[0031] The pump rotor body 30 is provided with two separate oil
outlet openings 40, 40' defined by outlet recesses 41, 41' which
are both radially orientated and open to the respective pumping
compartment 171, 172. The oil outlet openings 40, 40' both
respectively lie in a cylindrical plane defined by the cylindrical
outer surface of the pump rotor body 30. In the shown embodiment,
the pump rotor 14 rotates in a clockwise direction so that the oil
outlet openings 40, 40' are both arranged in the lagging fourth of
the respective rotating pumping compartment 171, 172 so that the
respective oil outlet opening 40, 40' arrives at the commutation
sector 60 in the final part of the compression phase of the
respective pumping compartment 171, 172. The opening angle 66 of
the oil outlet openings is slightly smaller than the commutation
sector angle 67 of the commutation sector 60 where the cylindrical
commutation slit is gas-tight. The oil outlet openings 40, 40' are
both provided axially adjacent to the ring-like front end wall 62
which is provided with the gas outlet opening 22 and the gas inlet
opening 26. FIG. 2 shows an orientation of the vacuum pump 10 when
the vacuum pump 10 is mounted in an automobile. The ring-like front
end wall 62 can, for example, lie below the other front end wall 64
so that oil is collected at the ring-like front end wall 62 due to
gravity.
[0032] The oil outlet openings 40, 40' are fluidically connected
with corresponding oil discharge openings 44, 44' which are located
at the axial coupling end 72 of the pump rotor body 30. The oil
outlet opening 40, 40' and the corresponding oil discharge openings
44, 44' are connected by respective oil ducts 42, 42', 43, 43',
which are a radial bore duct 42, 42' and an axial bore duct 43,
43'.
[0033] Both oil discharge openings 44, 44' are provided with a
check valve 76, 76', respectively, which comprises a sheet-like
valve body 45, 45' and a valve stop 46, 46' which limits the
opening movement of the valve body 45, 45'. The valve body 45, 45'
is defined by a sheet-like flexible tongue and opens the oil
discharge openings 44, 44' when the pressure of the fluid in the
respective oil outlet opening 40, 40' is above an opening pressure
difference which is, for example, 100 mbar.
[0034] When the pump 10 is in use and the pump rotor 14 is
rotating, gas, in particular, air, is sucked through the pump inlet
28 and the gas inlet opening 26 into the rotating pumping
compartment 172 at the suction side. The gas is transported in the
rotating pumping compartment 172 to the compression side so that
the compressed gas is pumped through the gas outlet opening 22 to
the pump outlet 24. The pump outlet 24 can be provided with a check
valve which avoids a flow back of gas into the pumping chamber
17.
[0035] During all pumping phases, a limited amount of oil is pumped
into the interior of the pump 10 so that oil is also accumulated
within the pumping chamber 17. The oil in the pumping chamber 17 is
in particular accumulated at the bottom ring-like front end wall 62
and is accumulated in the remaining volume of the compression-sided
pumping compartment 171 in the final compression phase. As soon as
the fluid pressure in the pumping compartment 172 is higher than
the atmospheric counter pressure plus the opening pressure
difference, the corresponding check valve 76 opens and the oil is
discharged to the area of the coupling structure 70.
[0036] The check valve 76 closes as soon as the oil outlet opening
40 is completely covered by the circumferential wall 80 in the
commutation sector 60.
[0037] The present invention is not limited to embodiments
described herein; reference should be had to the appended
claims.
* * * * *