U.S. patent application number 11/568215 was filed with the patent office on 2008-05-29 for radial swivel motor and process for manufacturing same.
Invention is credited to Torsten Baustian, Stefan Beetz, Winfried Krueger, Joachim Uecker.
Application Number | 20080124229 11/568215 |
Document ID | / |
Family ID | 34967535 |
Filed Date | 2008-05-29 |
United States Patent
Application |
20080124229 |
Kind Code |
A1 |
Beetz; Stefan ; et
al. |
May 29, 2008 |
Radial Swivel Motor and Process for Manufacturing Same
Abstract
To improve the surface finish of the inner circumferential
surfaces of the stator and to reduce the manufacturing effort, it
is proposed that the stator with a stator housing 1 and with the
stator blades 13 have a two-part design and to insert the stator
blade 13 into the stator housing 5 in such a way that they rotate
in unison. In terms of the process, it is proposed that a
commercially available tube with an inner circumferential surface
suitable for use as a sealing surface be used and that
longitudinally extending joining means be prepared. The stator
blades 13 manufactured as an individual part receive corresponding
joining means, so that the stator housing 5 and the stator blades
13 are welded, clamped or screwed together.
Inventors: |
Beetz; Stefan; (Barnim,
DE) ; Krueger; Winfried; (Parchim, DE) ;
Baustian; Torsten; (Crivitz, DE) ; Uecker;
Joachim; (Techentin, DE) |
Correspondence
Address: |
MCGLEW & TUTTLE, PC
P.O. BOX 9227, SCARBOROUGH STATION
SCARBOROUGH
NY
10510-9227
US
|
Family ID: |
34967535 |
Appl. No.: |
11/568215 |
Filed: |
April 14, 2005 |
PCT Filed: |
April 14, 2005 |
PCT NO: |
PCT/DE05/00681 |
371 Date: |
August 21, 2007 |
Current U.S.
Class: |
417/355 ;
417/534 |
Current CPC
Class: |
F15B 15/12 20130101 |
Class at
Publication: |
417/355 ;
417/534 |
International
Class: |
F04B 17/00 20060101
F04B017/00; F04B 39/10 20060101 F04B039/10 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 22, 2004 |
DE |
10 2004 020 190.0 |
Claims
1. A radial swivel motor, comprising: a stator with at least one,
radially inwardly directed stator blade; a rotor mounted in said
stator with rotor blades, which form between said rotor and said
stator at least one hydraulic, variable-volume pressure chamber and
just as many hydraulic, variable-volume drain chambers; frame
sealing elements in said stator blades and in said rotor blades,
wherein said pressure chambers and said drain chambers are sealed
hydraulically against each other by said frame sealing elements in
said stator blades and said rotor blades, said stator having a
multi-part design comprising a stator housing and said stator
blade, said stator blade being inserted into said stator housing in
such a way that said stator housing and said stator blade rotate in
unison.
2. A radial swivel motor in accordance with claim 1, wherein said
stator housing has for each said stator blade a longitudinally
extending mounting slot and each said stator blade has a mounting
tongue fitting said mounting slot and said stator housing and said
mounting tongue of said stator blade are connected to one another
by a weld seam prepared on the outer circumference of said stator
housing.
3. A radial swivel motor in accordance with claim 2, wherein to
form a groove for said weld seam, said mounting slot of said stator
housing and said mounting tongue in said stator blade have circular
conical surfaces.
4. A radial swivel motor in accordance with claim 1, wherein said
stator housing, for each said stator blade, has at least one
longitudinally extending wedge-shaped groove and each said stator
blade has an outer shape fitting said wedge-shaped groove, said
wedge-shaped groove and the outer shape of said stator blade having
such external dimensions that clamping and self-locking pressing
are achieved and have a cross section with a dovetail profile.
5. A radial swivel motor in accordance with claim 1, wherein for
mutual bracing, said stator housing and each said stator blade have
fastening holes, said stator housing is provided with a fitting
groove and each said stator blade is provided with a fitting tongue
to mutually secure the positions, and each said stator blade
carries at least one said sealing element extending over its entire
length to guarantee sealing between said pressure chamber and said
drain chamber.
6. A radial swivel motor in accordance with claim 1, wherein for
securing against rotation, said stator housing has at least one
position-securing groove extending over the entire axial length for
each said stator blade and said stator blade is designed in its
outer area as a fitting tongue, while each said stator blade has a
wedge-shaped design over an entire axial length thereof in the area
of lateral surfaces thereof for clamping and self-locking
frictional engagement, and a spacer shell having lateral surfaces
extending in a wedge-shaped pattern on one side and on the other
side between two said stator blades.
7. A process for manufacturing a radial swivel motor, the process
comprising: providing a rotor; providing stator covers; providing
individual stator blades; providing sealing elements; cutting a
commercially available tube bar material to a length with an inner
circumferential surface suitable for use as a sealing surface to
manufacture a stator housing, the inner contour of said inner
circumferential surface being prepared and front surfaces being
finally leveled off and provided with recesses for said sealing
elements and with holes for fastening said stator covers, wherein
said stator is assembled nondetachably from said stator housing and
said individual stator blades, wherein each said stator blade is
manufactured with a finished contour providing longitudinally
extending joining means fitting said stator housing.
8. A process in accordance with claim 7, wherein said stator
housing receives said mounting slots and each said stator blade
receives mounting tongues, which are welded together in the
assembled state on the outer surface of said stator housing.
9. A process in accordance with claim 7, wherein said stator
housing receives said wedge-shaped grooves and each said stator
blade receives has a wedge-shaped outer shape, which are pressed
together with said stator housing into a respective one of said
grooves in the assembled state on the outer surface of said stator
housing.
10. A process in accordance with claim 7, wherein said stator
housing receives said fastening holes and said fitting grooves and
each said stator blade receives fastening holes and a fitting
tongue, which are screwed together in the fitted state on the outer
surface of said stator housing.
11. A process in accordance with claim 7, wherein a commercially
available tube without special requirements on the surface finish
of the inner circumferential surface is used to manufacture said
stator housing, said stator housing has said position-securing
grooves and each said stator blade receives an outer shape
coordinated with said position-securing grooves as well as lateral
wedge surfaces, and a spacer shell with lateral wedge surfaces is
inserted between two said stator blades, said stator blades and
said spacer shells being pressed together on their wedge surfaces
in a self-locking manner.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. National Phase application of
International Application PCT/DE 2005/000681 and claims the benefit
of priority under 35 U.S.C. .sctn. 119 of German Patent Application
DE 10 2004 020 190.0 filed Apr. 22, 2004, the entire contents of
which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention pertains to a swivel motor according
to the preamble of claim 1 and to a corresponding manufacturing
process according to the preamble of claim 7
BACKGROUND OF THE INVENTION
[0003] Such swivel motors are used especially in the aircraft and
automobile industries to perform a great variety of tasks. A
preferred field of application is in the vehicle industry, where
the swivel motor is used for the roll stabilization of a motor
vehicle in conjunction with stabilizers.
[0004] Such a swivel motor is described, for example, in DE 197 25
412 C2. This swivel motor comprises a stator, which is connected to
a first stabilizer part, and a rotor, which is in connection with a
second stabilizer part. The stator has two radially directed stator
blades and the rotor has two, likewise radial rotor blades. The two
stator blades and the two rotor blades form, in conjunction with
two front-side covers, two hydraulic working chambers, which are
located opposite each other, so that the stator blades and the
rotor blades can be pivoted in relation to one another against the
hydraulic load in one of the two working chambers.
[0005] For the inner sealing of the two working chambers between
them, each stator blade is equipped with a frame sealing element,
which is inserted into the stator blade and is sealingly in contact
with the outer circumference of the rotor, while each rotor blade
carries an identical frame sealing element, which is sealingly in
contact with the inner circumference of the stator.
[0006] The stator and the two stator blades are made in one piece,
so that the inner surfaces have a complicated contour. These inner
surfaces have different tasks to perform, the lateral surfaces of
the stator blades being designed for a pure stop function, whereas
the inner circumferential surfaces of the stator act as sliding and
sealing surfaces.
[0007] A cold-extruded tube, which is first turned to the
corresponding lengths of a stator housing, is used as the blank for
manufacturing such a stator under mass production conditions. The
inner contour of each blank is then finished by the manufacturing
process broaching in three passes. The surface finish of Rz=10 that
can thus be attained at best is sufficient for the stop function.
This finish is unsatisfactory for the sliding and sealing function
of the inner circumferential surfaces of the stator because a
surface finish of Rz=1.0 to 2.0 is usually required herefor.
[0008] Therefore, a swivel motor equipped with such a stator fails
to reach its performance parameters because the inner sealing
between the pressurized working chamber and the pressureless
working chamber cannot be guaranteed due to the roughness of the
sealing surfaces. Because of the rough surface of the stator, the
frame sealing elements are also subject to greater wear, so that
the swivel motor also has a limited service life only. Furthermore,
the manufacture of such a stator especially by the broaching
process is very complicated in terms of manufacturing technology
and expensive.
[0009] To improve the sealing function, attempts were already made
to improve the surface finish by a subsequent lapping. There also
were efforts to develop frame sealing elements that adapt
themselves to the rough surface. All these attempts failed
ultimately because of the high costs or the limited installation
conditions.
SUMMARY OF THE INVENTION
[0010] The basic object of the present invention is therefore to
improve the surface finish of the inner circumferential surfaces of
the stator of a swivel motor of this class and to reduce the effort
needed for manufacture at the same time.
[0011] According to the invention, a radial swivel motor is
provided comprising a stator with at least one, radially inwardly
directed stator blade and a rotor mounted in the stator with rotor
blades. The rotor blades form between the rotor and the stator at
least one hydraulic, variable-volume pressure chamber and just as
many hydraulic, variable-volume drain chambers. Frame sealing
elements are in the stator blades and in the rotor blades. The
pressure chambers and the drain chambers are sealed hydraulically
against each other by the frame sealing elements in the stator
blades and the rotor blades. The stator has a multi-part design
comprising a stator housing and the stator blade. The stator blade
is inserted into the stator housing in such a way that the stator
housing and the stator blade rotate in unison.
[0012] The stator housing may have, for each stator blade, a
longitudinally extending mounting slot. Each stator blade may then
have a mounting tongue fitting the mounting slot. The stator
housing and the mounting tongue of the stator blade may be
connected to one another by a weld seam prepared on the outer
circumference of the stator housing.
[0013] To form a groove for the weld seam, the mounting slot of the
stator housing and the mounting tongue in the stator blade may have
circular conical surfaces.
[0014] The stator housing may have, for each stator blade at least
one longitudinally extending wedge-shaped groove. Each stator blade
may have an outer shape fitting the wedge-shaped groove. The
wedge-shaped groove and the outer shape of the stator blade may
have such external dimensions that clamping and self-locking
pressing are achieved and have a cross section with a dovetail
profile.
[0015] For mutual bracing, the stator housing and each stator blade
may have fastening holes. The stator housing may be provided with a
fitting groove and each stator blade may be provided with a fitting
tongue to mutually secure the positions. Each stator blade may
carry at least one sealing element extending over its entire length
to guarantee sealing between the pressure chamber and the drain
chamber.
[0016] For securing against rotation, the stator housing may have
at least one position-securing groove extending over the entire
axial length for each stator blade. The stator blade may be
designed in its outer area as a fitting tongue. Each stator blade
may have a wedge-shaped design over an entire axial length thereof
in the area of lateral surfaces thereof for clamping and
self-locking frictional engagement. A spacer shell having lateral
surfaces extending in a wedge-shaped pattern may be inserted on one
side and on the other side between two stator blades.
[0017] According to another aspect of the invention, a process is
provided for manufacturing a radial swivel motor. The process
includes providing a rotor; providing stator covers providing
individual stator blades and providing sealing elements. A
commercially available tube bar material is cut to a length with an
inner circumferential surface suitable for use as a sealing surface
to manufacture a stator housing. The inner contour of the inner
circumferential surface is prepared and front surfaces are finally
leveled off and provided with recesses for the sealing elements and
with holes for fastening the stator covers. The stator is assembled
nondetachably from the stator housing and the individual stator
blades. Each stator blade is manufactured with a finished contour
providing longitudinally extending joining means fitting the stator
housing.
[0018] The stator housing may have the mounting slots and each
stator blade may have mounting tongues. The tongues are inserted
into the slots and are welded together in the assembled state on
the outer surface of the stator housing.
[0019] The stator housing may have wedge-shaped grooves and each
stator blade may have a wedge-shaped outer shape. The wedge-shaped
outer shape is pressed into a groove together with the stator
housing into a respective one of the grooves in the assembled state
on the outer surface of the stator housing.
[0020] The stator housing may have the fastening holes and the
fitting grooves and each stator blade may have fastening holes and
a fitting tongue, which are screwed together in the fitted state on
the outer surface of the stator housing.
[0021] A commercially available tube may be used without special
requirements on the surface finish of the inner circumferential
surface, to manufacture the stator housing. The stator housing may
have position-securing grooves. Each stator blade may receive an
outer shape coordinated with the position-securing grooves as well
as lateral wedge surfaces. A spacer shell with lateral wedge
surfaces may be inserted between two stator blades. The stator
blades and the spacer shells may be pressed together on their wedge
surfaces in a self-locking manner.
[0022] The novel swivel motor and the novel manufacturing process
eliminate the drawbacks of the state of the art.
[0023] The present invention will be explained in more detail on
the basis of a number of exemplary embodiments. The various
features of novelty which characterize the invention are pointed
out with particularity in the claims annexed to and forming a part
of this disclosure. For a better understanding of the invention,
its operating advantages and specific objects attained by its uses,
reference is made to the accompanying drawings and descriptive
matter in which preferred embodiments of the invention are
illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In the drawings:
[0025] FIG. 1 is a longitudinal sectional view of a radial swivel
motor;
[0026] FIG. 2 is a cross sectional view of a first embodiment of
the swivel motor;
[0027] FIG. 3 is a perspective view of the stator housing according
to FIG. 2;
[0028] FIG. 4 is a perspective view of a stator blade according to
FIG. 2;
[0029] FIG. 5 is a cross sectional view of a second embodiment of
the swivel motor;
[0030] FIG. 6 is a perspective view of a form of the stator housing
according to FIG. 5;
[0031] FIG. 7 is a perspective view of another form of the stator
housing according to FIG. 5;
[0032] FIG. 8 is a perspective view of a stator blade according to
FIG. 5;
[0033] FIG. 9 is a perspective view of the stator housing according
to a third embodiment of the swivel motor;
[0034] FIG. 10 is a perspective view of a stator blade of the third
embodiment;
[0035] FIG. 11 is a cross-sectional view of a fourth embodiment of
the swivel motor; and
[0036] FIG. 12 is a perspective view of the stator according to
FIG. 11.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] Referring to the drawings in particular, According to FIG.
1, the swivel motor comprises a stator 1 and a rotor 2, the stator
1 being connected to a first stabilizer part 3, on the one hand,
and the rotor 2 being connected to a second stabilizer part 4, on
the other hand.
[0038] The stator 1 comprises a cylindrical stator housing 5, a
first stator cover 6 arranged on one side of the stator housing 5
and a second stator cover 7 located on the other side of the stator
housing 5. Both stator covers 6, 7 are rigidly screwed to the
stator housing 5 and equipped with a through bearing bore each. A
rotor shaft 8 of the rotor 2 is rotatably fitted into the bearing
bores of the two stator covers 6, 7, which the bearing bores are
located opposite each other, and hydraulically sealed against the
two stator covers 6, 7 by means of corresponding sealing elements
9, 10.
[0039] As is shown in FIGS. 2, 5 and 11, the rotor 2 has two rotor
blades 11, which are located opposite each other. These rotor
blades 11 are made in one piece with the rotor shaft 8 and are
coordinated with their radially directed heads with the inner wall
of the stator housing 5. Each rotor blade 11 is equipped for this
purpose with a groove-like recess, which extends over its entire
axial length and is inserted into a frame sealing element 12. This
frame sealing element 12 consists in the known manner of a plastic
with an elastomeric core and a circular sealing frame, preferably
one made of PTFE. This frame sealing element 12 is sealingly in
contact by one of its long legs with the inner circumferential
surface of the stator housing 5 and by its two short legs with the
two stator covers 6, 7.
[0040] Two stator blades 13, which are located opposite each other
and are likewise provided with a groove-like recess extending over
the entire axial length of the stator housing 5, are inserted into
the stator housing 5. A frame sealing element 12 each, which is
sealingly in contact by one of its long legs with the outer
circumferential surface of the rotor shaft 8 and by its two short
legs with the two stator covers 6, 7, is also fitted into this
recess. Two pressure chambers 14, which are located opposite each
other and are under equal pressure, and two drain chambers 15,
which are located opposite each other and are under equal pressure,
whose volumes are variable due to the limited relative pivotability
between the stator blades 13 and the rotor blades 11, are thus
formed. The equality of pressures in the respective working
chambers 14 and drain chambers 15 located opposite each other is
achieved through the connection channels 16 prepared in the rotor
shaft 8.
[0041] The stator housing 5 and the two stator blades 13 have a
two-part design in a special manner.
[0042] Thus, the stator housing 5 is designed in a first embodiment
according to FIG. 3 as a tube and has two longitudinally extending
mounting slots 17 of a limited length, which are located opposite
each other, for the two stator blades 13. Each stator blade 13
according to FIG. 4 is correspondingly provided with a
longitudinally extending mounting tongue 18. Each mounting slot 17
has a circular conical surface, which becomes larger in the radial
direction from the internal diameter towards the external diameter
of the stator housing 5. By contrast, each mounting tongue 18 of
the stator blade 13 has a circular conical surface, which tapers in
the radial direction from the inside to the outside. The internal
dimensions of the mounting slot 17 and the external dimensions of
the mounting tongue 18 are coordinated with one another such that
the smaller dimensions of the mounting slot 17 and the larger
dimensions of the mounting tongue 18 can fit each other. The cone
angle is selected to be such that a groove suitable for a weld seam
19 is obtained in the fitted state.
[0043] In a second embodiment according to FIGS. 5 through 8, the
tubular stator housing 5 has two wedge-shaped grooves 20, which are
located opposite each other and extend over the length of the
stator housing 5. The wedge-shaped grooves 20 have, moreover, a
dovetailed cross section. Fitting this, the stator blade 13
according to FIG. 8 is provided with external dimensions that make
it possible to push the stator blade 13 axially into the
corresponding wedge-shaped groove 20 and prevent falling out of the
wedge-shaped groove 20 radially. The wedge angles of the
wedge-shaped grooves 20 and of the outer shape of the stator blade
13 are equal and are selected to be such that a clamping and
self-locking frictional engagement becomes established. As is shown
in FIG. 7, clamping and self-locking frictional engagement can be
achieved between the stator housing 5 and each stator blade 13,
analogously hereto, by two parallel wedge-shaped grooves 20'
directed in the same direction in the stator housing 5 and wedge
tongues corresponding hereto in the stator blade 13.
[0044] In a third embodiment according to FIGS. 9 and 10, the two
stator blades 13 are screwed to the tubular stator housing 5 and
additionally secured in their position. The securing in position is
achieved by means of a fitting groove 21 in the stator housing 5
and by a fitting tongue 22 at the stator blade 13. Instead of the
tongue-and-groove securing, pin-and-hole securing may also be
performed.
[0045] To ensure sealing between the working chambers on both sides
of the stator blade 13, each stator blade 13 is equipped with at
least one longitudinal groove for a sealing element 23.
[0046] In a fourth embodiment according to FIG. 11, the tubular
stator housing 5 has, for each stator blade 13, a position-securing
groove 24 extending over the entire axial length, whereas the
stator blade 13 is designed in its outer area as a fitting tongue.
The position-securing groove 24 of the stator housing 5 and the
fitting tongue area of the stator blade 13 form a tongue-and-groove
connection, which assumes exclusively the task of a means securing
against rotation. As an alternative, the means securing against
rotation may also comprise, as is shown in FIG. 12, two parallel
position-securing grooves 24' in the stator housing 5 and
correspondingly two fitting tongues in the stator blade 13.
[0047] In the area of its lateral surfaces that project from the
stator housing 5, the stator blade 13 is of a wedge-shaped design
over its entire axial length. A spacer shell 25 each, whose lateral
surfaces likewise extend in a wedge-shaped pattern, is inserted
between the two stator blades 13 inserted into the stator housing 5
on one side and on the other side in such a way that they are
secured against rotation. The wedge angles of the lateral surfaces
of the stator blades 13 and of the lateral surfaces of the spacer
shell 25 are equal and are selected to be such that a clamping and
self-locking frictional engagement is formed due to the spacer
shells 25 being pushed in, in the axial direction.
[0048] Such a stator 1 is manufactured as follows.
[0049] A commercially available drawn and internally honed tube is
used as the starting product for manufacturing the stator housing 5
in the first three embodiments according to FIGS. 1 through 10. The
inner circumferential surface of this tube has a surface finish of
Rz=2, maximum, because of its prior machining and is therefore very
well suited for use as a sealing surface. Therefore, no subsequent
fine machining is needed. The tube is turned off to the
corresponding lengths of the stator housing 5. The mounting slot 17
for the first embodiment, the wedge-shaped grooves 20, 20' for the
second embodiment or the fitting groove 21 and the fastening holes
for the third embodiment are then prepared in the stator housing 5
according to a conventional machining operation.
[0050] The stator blades 13 are manufactured for this in the
conventional manner with the corresponding dimensions and shapes
and inserted into the stator housing 5.
[0051] The stator housing 5 and the stator blade 13 are then welded
together by a low-warpage welding process in the first embodiment,
pressed together in the second embodiment or secured in their
positions relative to one another and screwed together in the third
embodiment. The two front sides of the completed stator 1 are
finally levelled off in the conventional manner and the intended
holes in the covers and sealing grooves are prepared.
[0052] A commercially available tube, which does not have to meet
any special requirements on the surface finish of the inner
circumferential surface, is used as the starting product for
manufacturing the stator housing 5 in the fourth embodiments
according to FIGS. 11 and 12. The position-securing grooves 24
according to FIG. 11 or the position-securing groves 24' according
to FIG. 12 are then prepared in the stator housing 5.
[0053] The stator blades 13 are manufactured for this in the
conventional manner with the dimensions and shapes adapted to the
position-securing grooves 24, 24' and inserted into the stator
housing 5. At the same time, the spacer shells 25 are manufactured
in the conventional manner with such dimensions and in such a shape
that they fit between the two stator blades 13 when an axially
acting pressing force is applied and are in contact over their full
area with the inner circumferential surface of the stator housing
5. The inner surface of each spacer shell 25 is machined according
to a conventional superfinishing process to a surface finish of
Rz=1 to 2.
[0054] After finishing the individual parts, the stator blades 13
are pushed into the position-securing grooves 24, 24' and then
pressed against each other by means of the spacer shells 25 until
self-locking occurs.
[0055] The two front sides of the completed stator 1 are finally
leveled off in the conventional manner and the intended holes in
the covers and sealing grooves are prepared.
[0056] While specific embodiments of the invention have been shown
and described in detail to illustrate the application of the
principles of the invention, it will be understood that the
invention may be embodied otherwise without departing from such
principles.
* * * * *