U.S. patent application number 11/497564 was filed with the patent office on 2007-02-08 for machine with a rotatable rotor.
This patent application is currently assigned to Linde Aktiengesellschaft. Invention is credited to Alexander Glaab, Martin Steigerwald, Bernward Welschof.
Application Number | 20070031267 11/497564 |
Document ID | / |
Family ID | 37670095 |
Filed Date | 2007-02-08 |
United States Patent
Application |
20070031267 |
Kind Code |
A1 |
Glaab; Alexander ; et
al. |
February 8, 2007 |
Machine with a rotatable rotor
Abstract
A machine (1) has a rotor (3) located so that it can rotate in a
housing (2). The rotor is located at least partly in fluid, such as
coolant. To provide a machine which has lower losses with a higher
cooling capacity, the housing pressure can be reduced so that the
fluid transitions into the two-phase range. In one embodiment, the
housing pressure can be reduced by a suction device (7).
Inventors: |
Glaab; Alexander; (Hosbach,
DE) ; Steigerwald; Martin; (Glattbach, DE) ;
Welschof; Bernward; (Grossostheim, DE) |
Correspondence
Address: |
THE WEBB LAW FIRM, P.C.
700 KOPPERS BUILDING
436 SEVENTH AVENUE
PITTSBURGH
PA
15219
US
|
Assignee: |
Linde Aktiengesellschaft
Wiesbaden
DE
|
Family ID: |
37670095 |
Appl. No.: |
11/497564 |
Filed: |
August 1, 2006 |
Current U.S.
Class: |
417/313 |
Current CPC
Class: |
H02K 9/20 20130101; F04B
1/122 20130101; F04B 17/03 20130101 |
Class at
Publication: |
417/313 |
International
Class: |
F04B 53/00 20060101
F04B053/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 2, 2005 |
DE |
10 2005 036 307.5 |
Aug 12, 2005 |
DE |
10 2005 038 273.8 |
Claims
1. A machine, comprising: a rotor located in a housing, wherein the
rotor is located at least partly in fluid; and a device for
reducing a housing pressure such that the fluid transitions into a
two-phase range.
2. The machine as claimed in claim 1, wherein the device for
reducing housing pressure comprises a suction device.
3. The machine as claimed in claim 2, wherein an outlet line that
is in communication with the housing is connected with a suction
line of the suction device.
4. The machine as claimed in claim 2, wherein a pressure side of
the suction device is in communication with a reservoir.
5. The machine as claimed in claim 2, wherein a pressure side of
the suction device is in the form of a delivery line.
6. The machine as claimed in claim 3, further comprising a stop
valve that opens in a delivery direction and is located in the
outlet line downstream of the suction device.
7. The machine as claimed in claim 3, further comprising a bypass
line that is in communication with the outlet line and bypasses the
suction device.
8. The machine as claimed in claim 2, wherein the suction device
comprises a pump.
9. The machine as claimed in claim 8, wherein the suction device
further comprises a vacuum limiting device.
10. The machine as claimed in claim 9, wherein the vacuum limiting
device comprises a vacuum choke that is associated with the
pump.
11. The machine as claimed in claim 10, wherein the vacuum choke is
in the form of a control valve which is associated with a suction
side of the pump and can be pushed by a spring toward a closed
position and pushed by the housing pressure toward an open
position.
12. The machine as claimed in claim 9, wherein the vacuum limiting
device comprises a pressure compensator that is associated with the
pump.
13. The machine as claimed in claim 12, wherein the pressure
compensator is in the form of a control valve which is located in a
pump bypass line and is pushed toward an open position by a spring
and toward a closed position by the housing pressure.
14. The machine as claimed in claim 2, wherein the suction device
is in a drive connection with the machine.
15. The machine as claimed in claim 2, further comprising a drive
motor to drive the suction device, wherein the drive motor is
selected from the group consisting of an electric motor, a
hydraulic motor, or an internal combustion motor.
16. The machine as claimed in claim 2, wherein the machine is used
in a drive system with a booster pump, and wherein the booster pump
is in the form of a pump of the suction device.
17. The machine as claimed in claim 16, wherein the pump is in
communication by a suction line with a reservoir.
18. The machine as claimed in claim 1, wherein the machine is an
electrical machine.
19. The machine as claimed in claim 1, wherein the machine is a
hydraulic machine.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to German Application No.
10 2005 038 273.8, filed Aug. 12, 2005, and German Application No.
10 2005 036 307.5, filed Aug. 2, 2005, both of which applications
are herein incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a machine with a rotor that is
located so that it can rotate in a housing. The rotor is located at
least partly in fluid, such as a coolant.
[0004] 2. Technical Considerations
[0005] On similar machines of the known art, a housing pressure of
at least 1.5 bar is built up in the housing by means of suitable
resistances in an outlet line that leads from the housing to a
reservoir. On machines of this type where the housing is partly or
completely filled with fluid, such as coolant, for example, the
rotor rotates partly or completely in the fluid. High heat removal
and, thus, high cooling capacity can be achieved and, thus, the
machine can be operated at high output. At high speeds of rotation,
however, high losses occur, in particular churning losses, on
account of the viscous friction of the fluid, which, in turn,
results in low efficiency of the machine.
[0006] An object of this invention is to provide a machine of the
general type described above but that has lower losses and higher
cooling capacity than known machines.
SUMMARY OF THE INVENTION
[0007] The invention teaches that the housing pressure can be
reduced such that the fluid transitions into the two-phase range.
According to the invention, therefore, the internal pressure in the
housing is reduced, for example, to a value of less than
approximately 0.8 bar, so that the fluid which is saturated at the
ambient temperature transitions to super-saturation and releases
gas. This resulting two-phase fluid having a liquid phase and a gas
phase, where the area of separation of the phases is in the
vicinity of the rotor, has significantly lower viscous friction. As
a result of which, reduced losses, in particular churning losses,
occur on the rotating rotor and, thus, the machine has a higher
level of efficiency. The cooling capacity remains almost unchanged
on account of the almost uniform and unchanging quantity of
fluid.
[0008] In one preferred non-limiting embodiment of the invention,
the housing pressure can be reduced by means of a suction device.
With a suction device, it is possible to easily generate a vacuum
to reduce the pressure inside the housing.
[0009] Preference is thereby given to a connection between an
outlet line that is in communication with the housing and a suction
side of the suction device.
[0010] In one embodiment of the invention, the pressure side of the
suction device can be connected with a reservoir. As a result, the
suction device can easily be located in the outlet line that runs
from the housing to the reservoir and is already present.
[0011] In an additional advantageous embodiment of the invention,
the pressure side of the suction device is realized in the form of
a delivery line. With a suction line of this type, an additional
user can therefore be supplied with fluid. If hydraulic fluid is
used as the fluid, it thereby becomes possible with the suction
device to supply another user with hydraulic fluid, e.g., a feed
circuit or a steering device.
[0012] In one development of the invention, in the outlet line
downstream of the suction line there is a stop valve, such as a
check valve, that opens in the delivery direction. It thereby
becomes possible for the suction device to produce a vacuum to
reduce the housing pressure.
[0013] Preferably, a bypass line is provided, which is in
communication with the outlet line, and bypasses the suction
device, and which can be used to equalize the pressure if the
housing is totally evacuated by the suction device.
[0014] In one preferred embodiment of the invention, the suction
device has a pump. A pump is a simple and easy way to generate a
vacuum to reduce the pressure inside the housing.
[0015] In one development of the invention, the suction device has
a vacuum limiting device. With a vacuum limiting device, an
excessive vacuum, which can cause the liquid to foam, can be easily
prevented. It thereby becomes possible to guarantee a satisfactory
and reliable lubrication of the roller bearings that support the
rotor by the fluid.
[0016] The vacuum choke is thereby advantageously realized in the
form of a control valve, which is associated with the suction side
of the pump, and is pushed toward a closed position by a spring and
toward an open position by the housing pressure. With a vacuum
choke of this type, the vacuum in the housing produced by the pump
can be limited easily and reliably by the adjustment of the
spring.
[0017] In an additional preferred embodiment of the invention, the
vacuum limiting device is formed by a pressure compensator that is
associated with the pump.
[0018] The pressure compensator can be preferably realized in the
form of a control valve, which is located in a pump bypass line,
and is pushed toward an open position by a spring and toward a
closed position by the housing pressure. The vacuum produced by the
pump can also be easily and reliably limited by adjusting the
spring on a pressure compensator of this type.
[0019] The suction device can be in a drive connection with the
machine, as a result of which no separate drive device needs to be
provided for the drive of the suction device.
[0020] It is also possible to provide a separate drive motor for
the drive of the suction device, such as an electric motor or a
hydraulic motor or an internal combustion motor. As a result of
which, the suction device can be driven in a simple manner.
[0021] The pump of the suction device can be formed by a separate
pump, which is used only for the generation of a vacuum in the
housing.
[0022] It is particularly advantageous if a machine incorporating
features of the invention is used in a drive system with a booster
pump, with the booster pump realized in the form of a pump of the
suction device. Consequently, the booster pump of the drive system,
which is already present, such as, for example, a feed pump for the
supply of a feed circuit or a steering pump for the supply of a
steering device, can be used to generate the vacuum in the housing,
whereby there is a low construction expense for the machine.
[0023] The pump can be in communication by means of a suction line
with a reservoir. As a result of which, it is possible to easily
achieve an additional suction-side connection of the booster pump,
which is already present, to the reservoir to supply the users that
are supplied by the pump with hydraulic fluid.
[0024] In one preferred embodiment of the invention, the machine is
realized in the form of an electrical machine, for example in the
form of a synchronous or asynchronous machine. As a result of the
reduction of the churning losses of the rotor in accordance with
the invention, a high output can be achieved with low losses, and,
thus, high efficiency, on an electrical machine of the
invention.
[0025] In an additional preferred embodiment, the machine can be
realized in the form of a hydraulic machine, for example in the
form of an axial piston machine, utilizing the swashplate
construction with a cylinder drum that forms the rotor. As a result
of the reduction of the churning losses of the rotating cylinder
drum of the invention, it is thereby possible to operate the axial
piston machine at high speeds of rotation and low losses, and
thereby with high efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Additional advantages and details of the invention are
explained in greater detail below on the basis of the exemplary
embodiments which are illustrated in the accompanying schematic
figures, in which like reference numbers identify like parts
throughout.
[0027] FIG. 1 shows a machine of the invention in a schematic
illustration;
[0028] FIG. 2a shows a first embodiment of a suction device;
[0029] FIG. 2b shows a second embodiment of a suction device;
and
[0030] FIG. 2c shows an additional embodiment of a suction
device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] FIG. 1 shows a machine 1 of the invention in the form of an
electrical machine or a hydraulic machine, having a rotor 3 which
is located so that it can rotate in a housing 2. The interior of
the housing 2 is at least partly and preferably completely filled
with fluid, for example with coolant in the form of hydraulic
fluid. The interior of the housing 2 is connected to an outlet line
5 which runs to a reservoir 6.
[0032] The section of the outlet line 5 that is in communication
with the interior of the housing 2 is connected to the suction side
of a suction device 7. The section of the outlet line 5 that is
connected to the pressure side of the suction device 7 leads to the
reservoir 6. In the outlet line 5, downstream of the suction device
7, there is a stop valve 8, which can be realized in the form of a
check valve that opens toward the reservoir 6. Downstream of the
stop valve 8, in the outlet line 5, are a cooler device 9 and a
filter device 10.
[0033] To bypass the suction device 7, a bypass line 5a is
connected to the outlet line 5.
[0034] FIG. 2a shows a first embodiment of a suction device 7. The
suction device 7 has a pump 11 which is connected on the suction
side to the section of the outlet line 5 that is connected with the
housing 2, and with the pressure side emptying into the section of
the outlet line 5 that leads to the reservoir 6.
[0035] The suction device 7 has a vacuum limiting device 12, which
is formed by a vacuum choke 13 that is associated with the pump 11.
The vacuum choke 13 is formed by a control valve that acts as a
choke in intermediate positions, is associated with the suction
side of the pump 11, and is pushed toward a closed position 13a by
a spring 14 and toward an open position 13b by the housing pressure
that is present in the outlet line 5. For this purpose, a control
pressure line 15 is provided which runs from the section of the
outlet line 5 that is in connection with the housing to a control
surface of the vacuum choke 13 that acts toward the open position
13b.
[0036] In the embodiment illustrated in FIG. 2b, the vacuum
limiting device 12 is formed by a pressure compensator 16 that is
associated with the pump 11. The pressure compensator 16 is
realized in the form of a control valve that acts as a choke in
intermediate positions, and is located in a pump bypass line 17
that is connected to the outlet line 5. The pressure compensator 16
that is realized in the form of a control valve is pushed toward an
open position 16a by a spring 19 and toward a closed position 16b
by the housing pressure. For this purpose, a control surface of the
pressure compensator 16 that acts toward the closed position 16b is
connected to a control pressure line 18, which is connected to the
section of the pump bypass line 17, and which is in communication
with the section of the outlet line 5 that is in communication with
the housing 2.
[0037] The pump 11, as illustrated in FIGS. 2a and 2b, is realized
in the form of a separate pump, which is provided exclusively for
the production of a vacuum in the interior of the housing 2 of the
machine 1.
[0038] In the embodiment illustrated in FIG. 2c, the pump 11 is
formed by a booster pump which is already present, for example a
feed pump for the supply of a feed circuit or of a steering pump
for the supply of a steering system or a hydraulic pump for the
supply of additional users, for example of a hydraulic system, for
the operation of a mobile industrial truck. The section of the
outlet line 5 that is connected to the pressure side of the suction
device 7 is realized in the form of the delivery line of the pump
11. For the connection of the pump 11 with the reservoir 6, the
suction side of the pump 11 is connected to a suction line 20,
which is in communication with the reservoir 6. The suction line 20
is connected with the section of the outlet line 5 that leads to
the suction side of the pump 11 downstream of the vacuum limiting
device 12.
[0039] The pump 11 can be associated with a vacuum limiting device
12 as illustrated in FIG. 2a. It is also possible to provide a
vacuum limiting device 12 as illustrated in FIG. 2b.
[0040] The pump 11 of the suction device 7 can be in a drive
connection with the machine 1. It is also possible to provide a
separate driver motor, such as an electric motor for example, a
hydraulic motor, or an internal combustion motor.
[0041] The machine can be an electrical machine, e.g., in the form
of a synchronous or asynchronous machine, or in the form of a
hydraulic machine, for example in the form of an axial piston
machine that utilizes a swashplate construction, whereby the
cylinder drum forms the rotor.
[0042] It will be readily appreciated by those skilled in the art
that modifications may be made to the invention without departing
from the concepts disclosed in the foregoing description.
Accordingly, the particular embodiments described in detail herein
are illustrative only and are not limiting to the scope of the
invention, which is to be given the full breadth of the appended
claims and any and all equivalents thereof.
* * * * *