DE102006010058A1 - Servo-steering device e.g. hydraulic servo steering device, for motor vehicle, has centering device with inner and outer sleeves that are designed as sheet metal deformation parts, where outer sleeve is adjustably supported on inner sleeve - Google Patents

Abstract

The device has a centering device (10) determining a predetermined initial position of an input shaft (2) to an output shaft (3), to allow an axial movement of the input shaft. The device (10) has an inner sleeve (11) supported axially by the input shaft. An outer sleeve (13) is adjustably supported on the sleeve (11) by rolling bodies that are spring-loaded radially outwards and distributed over the circumference. The sleeves are designed as sheet metal deformation parts. The sleeve (13) has a radial flange (18) axially supported at a front surface (23) of the shaft (3) by centering balls.

Description

Territory of invention

The The invention relates to a power steering device for motor vehicles, with a Steering housing, in which coaxial with each other, an input shaft connected to a steering wheel is operatively connected, and an output shaft, the one as a pinion has trained end portion, in turn, over a Steering gear with steerable wheels of the motor vehicle is supported, with a torsion bar, the one end with the input shaft and the other end with the output shaft is firmly connected, with a centering device, on the one hand the definition of a specific basic position of the input shaft to the output shaft and on the other hand, an axial movement of the input shaft permitted, and with a means for applying an external force on the steering device.

background the invention

Servo steering devices of the generic type have long been known in various embodiments. That's how it shows DE 44 04 533 C2 a steering valve for a center-centric power steering system for supplying an actuator with hydraulic pressure. This steering valve consists of an input shaft, an output shaft, a torsion bar, which is connected at one end to the input shaft and the other end to the output shaft, and a valve sleeve surrounding the input shaft. Within the steering valve, a torsionally rigid, axially elastic element in the form of a spiral spring or a metal bellows is arranged, which is fixed with one end to the input shaft. At the other end, the elastic element is connected to a latching device securing a radial displacement against the valve sleeve up to a predetermined torque.

Furthermore, by the DE 197 47 638 C1 an electric motor assisted servo steering device of the generic type known, referred to here as a power steering system for motor vehicles, in which a detection unit for detecting a force acting on the input shaft steering torque is provided, which in turn each includes a connected to the input shaft and an output member magnetic ring and an associated sensor , As the input shaft and the output shaft or pinion shaft are mounted within the same female housing and centered to each other, this document is not apparent in detail.

The DE 102 03 384 A1 describes a hydraulic power steering system of a mechanical rack and pinion steering, wherein a servo cylinder is provided, the piston rod is connected via tie rods with the steerable wheels. The servo cylinder has two chambers, which can be acted upon by hydraulic lines selectively with hydraulic fluid. For this purpose, a rotary valve is used which has an input shaft and an output shaft. Input shaft and output shaft are connected together in a proven manner via a torsion bar.

to Distribution of a hydraulic fluid to the chambers of the servo cylinder the rotary valve is provided with a valve sleeve, the tight with the output shaft is in communication. To vary the torque to be able to which for a rotation of the input shaft relative to the output shaft neces sary is, in addition, a centering device is provided which essentially from a centering piston, a centering ring and several between them arranged balls consists. The centering ring is by means of press fit firmly in a shoulder of the valve sleeve recorded and thus rotatably with connected to the output shaft. The centering piston is in turn rotatably connected to the input shaft by a plurality of coupling balls, which engage in grooves in the input shaft and in the centering piston and in this way the centering non-rotatably, but axially displaceable connect to the input shaft.

The Centering balls are between V-shaped grooves arranged in the centering piston and in the centering ring. The centering piston and the centering ring are relative to each other in the circumferential direction aligned so that the centering balls lie against the bottom of the groove, when the input shaft and the output shaft are relative to each other are in the starting position. When the input shaft as well as the output shaft and thus the centering piston and the centering against each other be twisted, press the centering balls the centering piston away from the centering, since they on the then acting as ramp surfaces Sides of the V-grooves are running.

The DE 20 2004 013 834 U1 shows a power steering valve, which essentially turns off on a specially designed actuator which is arranged in the interior of the power steering valve and can rotate an input and an output member relative to each other from a central position.

Finally, it is known from WO 2005/063549 A1 a gear lock for a so-called superposition steering a motor vehicle for locking a gear associated with the transmission or cooperating rotatable gear part with respect to its rotational movement known. Essentially, it is provided here that by means of a clamping body, in particular a Pinch roller, over a contour of an inner circumferential surface of an outer ring and a contour of an outer circumferential surface of an inner ring of the inner ring with the outer ring against a resilient force is positively locked. The pinch roller is held in an activation cage, which in turn lockable via an actuatable latch member.

Task of invention

In front In this background, the invention is based on the object to provide further improved servo steering device for motor vehicles, the in view of the state of the art in ensuring safe operation easier to manufacture and therefore less expensive.

Summary the invention

The Invention relates according to the features of Claim 1, a servo-steering device for motor vehicles, first with a steering housing, in which coaxial with each other, an input shaft, which with a Steering wheel is operatively connected, and an output shaft, the one as Pinion trained end portion, which in turn has a Steering gear with steerable wheels of the motor vehicle is supported, with a torsion bar, the at one end with the input shaft and at the other end with the output shaft is firmly connected, with a centering device, on the one hand the definition of a specific basic position of the input shaft to the output shaft and on the other hand, an axial movement of the input shaft permitted, and with a means for applying an external force on the steering device.

Furthermore this power steering apparatus is characterized in that the Centering an inner sleeve which in turn is supported by the input shaft and with the same is axially and rotationally connected, that on the inner sleeve by means of a plurality of evenly over the Scope of the same distributed and radially outwardly sprung rolling elements a in the axial direction against the output shaft at least spring-loaded Outer sleeve axially slidably, but is mounted rotationally fixed, and that the outer sleeve on her has a radial flange facing the output shaft end, the axially over a plurality of centering balls on an adjacent end face of Output shaft supported.

The under claims describe preferred developments or refinements of Invention.

After that is according to one particularly advantageous embodiment of the invention provides that the rolling elements for Torque transmission between inner sleeve and outer sleeve radially inside of at least one fixed to the inner sleeve and a spring force in the radial direction on the rolling elements exerting spring element form-fitting held as well as radially outside are guided within an axially facing radial groove of the outer sleeve, whereby a largely backlash-free connection of the input shaft realized to the output shaft.

The Spring element can by a spring ring with radially inward and radially outward directed spring tabs may be formed, with the inwardly directed Spring tabs are fixable within radial grooves of the inner sleeve, and the outward directed spring tabs serve the positive reception of the rolling elements.

As the invention further provides two or more rolling elements respectively to an axially aligned row of rolling elements be summarized, whereby the torque transmission further improved is.

Further is provided that the inner sleeve by force fit Press fit and / or material fit, preferably by welding, is firmly connected to the input shaft.

When has appropriate further proved that inner and outer sleeve formed as Blechumformteile are, thereby consuming and costly cutting components are avoided.

Farther It is suggested that the outer sleeve by means of a spring is spring-loaded in the axial direction.

To Another embodiment of the invention provides that the Outer sleeve with Help a pressure medium in the axial direction over the centering against the output shaft is pressed. In this connection, it is advantageous when the spring element is arranged in a pressure chamber, which via a Pressure line acted upon by a pressure medium and the axially movable Outer sleeve limited is. This design allows, by means of the spring element a constant contact force over the outer sleeve and to exert the centering balls on the output shaft while by applying acting as a piston outer sleeve means of the pressure medium, such as a hydraulic oil, the contact pressure on the Output shaft additionally suitable for driving situations can be adjusted.

It is further provided that the centering balls form fit in mutually corresponding recesses of the radial flange of the outer sleeve and the adjacent end face of the off output shaft are held. These recesses preferably have contact surfaces for the centering ball, whose opening angle "α" in cross section is 90 ° to 180 °.

As the invention also provides, the steering gear by a rack and pinion with rack and connected linkage to the wheels be formed. Opposite that the steering gear also by a ball nut steering with threaded spindle and connected linkage to the wheels be.

Finally, can be provided that the means for applying a foreign force on the steering device by an electromechanical drive or is formed by a hydraulic drive.

Short description the drawings

The Invention will be described below with reference to the accompanying drawings on some embodiments explained in more detail. In this shows

1 a servo steering device in a longitudinal section,

2 the detail "Y" according to 1 with the detailed representation of a centering device,

3 an item drawing of the centering according to 2 in the plan view,

4 the section II after 3 .

5 the section II-II after 3 , and

6 the detail "Z" according to 5 ,

detailed Description of the drawings

In 1 is therefore a servo steering device with a steering housing 1 shown in which an input shaft 2 and an output shaft 3 are supported. The input shaft 2 is operatively connected in a known manner with a steering wheel not shown in detail.

The output shaft 3 is formed in a first section as a hollow shaft and a trained as a ball bearing 4 in the steering box 1 radially supported. A trained as a pinion end section 5 the output shaft 3 is about a known steering gear 6 and a known and thus not shown in detail connecting linkage also connected to steerable wheels of the motor vehicle.

The steering gear 6 is present by a rack and pinion gear with a rack 7 formed, which is in engagement with said pinion. However, it is also possible, for example, to provide a ball nut steering with a threaded spindle instead of the rack and pinion (not shown in detail). Within the hollow shaft designed as output shaft 3 the input shaft is supported 2 over camp 8th from.

Furthermore, a torsion bar known per se 9 provided, one end with the input shaft 2 and at the other end with the output shaft 3 firmly connected by bolts.

The input shaft 2 and the output shaft 3 are also by means of a so-called centering device 10 positively and non-positively connected. The centering device 10 serves here on the one hand, the determination of a certain basic position of the input shaft 2 to the output shaft 3 Also referred to as a neutral position, and allows limited axial movement of the input shaft 2 ,

By means of a not-shown, but well-known electromechanical or hydraulic drive can on the steering device, respectively the output shaft 3 or the steering gear 6 the same a foreign force in the sense of support or override the manual steering movement are applied.

Thus, the external force can be generated for example by an electronically controlled electric motor in which the manual by the driver to the input shaft 2 applied torque from a non-illustrated, the torsion bar 9 associated torque sensor detected and fed to a control unit, which in turn generates control signals for the electric motor, which in turn a support torque to the output shaft 3 or the steering gear 6 applies.

In contrast, if the assist torque is to be applied hydraulically, control valves in the form of rotary vane or rotary valves are predominantly used. As a result of a torsional stress of the torsion bar 9 In this case, a pressure oil inlet is opened by means of the rotary valve or rotary piston and a working space of a working piston is charged with pressurized oil such that an assisting torque is applied to the output shaft 3 acts.

As in the 2 to 6 is shown closer, the centering device 10 an inner sleeve 11 in turn, from the input shaft 2 supported and connected to the same axially and rotationally fixed. The inner sleeve 11 can either force conclusively by press fit and / or material fit, preferably by welding, with the input shaft 2 be firmly connected.

On the inner sleeve 11 is by means of a plurality of uniformly distributed over the circumference of the same rolling elements 12 one in the axial direction against the output shaft 3 spring-loaded outer sleeve 13 mounted axially displaceable but rotationally fixed, whereby the conditions for a torque transmission from the input shaft 2 on the output shaft 3 are created (see in particular the 2 to 5 ).

Appropriately, the inner sleeve 11 and the outer sleeve 13 designed as a simple Blechumformteile, whereby their production is avoided in a complex and costly cutting construction.

In the present case is the outer sleeve 13 by means of a spring element 14 axially spring-loaded in the form of a helical compression spring, which at one end via a ring element 15 on the steering housing 1 and at the other end, a gasket holder 16 with ring seal 17 on a radial flange 18 the outer sleeve 13 supported. However, the invention is not limited to this helical compression spring, but includes any suitable spring element 14 , For example, one or more leaf springs (not shown).

As 2 clarifies, is the outer sleeve 13 with the aid of a pressure medium in the axial direction over the centering balls 22 against the output shaft 3 pressed. In this conjunction, it is advantageous that the spring element 14 in the form of a helical compression spring in a pressure chamber 27 is arranged, which via a pressure line 28 with a pressure medium such as a hydraulic oil can be acted upon. This design allows, by means of the spring element 14 a constant contact force over the outer sleeve 3 and the centering balls 22 on the output shaft 3 exercise, while by acting on the acting as a piston outer sleeve 13 by means of the pressure medium, the contact pressure on the output shaft 3 can additionally be adjusted to suit the driving situation. This makes it possible to adjust the steering, for example, for a ride at high speed, which gives the driver an objectively increased steering and driving safety. For a trip at a lower speed, the pressure in the pressure chamber can be reduced, resulting in a more comfortable steering adjustment.

What the rolling elements 12 As far as they are initially in a conventional manner in a Wälzkörperkäfig 12a arranged and further between the inner and outer sleeve 11 . 13 radially inward of at least one on the inner sleeve 11 fixed and a spring force in the radial outward direction on the rolling elements 12 exercising spring element 19 held positively.

Radially outside are the rolling elements 12 within a radial groove pointing in the axial direction 20 the outer sleeve 13 guided. By the above measure is particularly advantageous given a backlash, which improved torque transmission from the inner sleeve 11 on the outer sleeve 13 Account taken:
The spring element 19 is according to a preferred embodiment by a spring ring with radially inwardly and radially outwardly directed spring tabs 19a respectively. 19b formed, with the inwardly directed spring tabs 19a within radial grooves 21 the inner sleeve 11 can be fixed, whereas the outwardly directed spring tabs 19b the positive reception of the rolling elements 12 serve.

According to 5 In the present case, a plurality are uniform over the circumference of the inner sleeve 11 distributed rolling element rows of preferably two rolling elements 12 provided, which also improved torque transmission from the inner sleeve 11 on the outer sleeve 13 results.

As in particular the 2 . 5 and 6 can be seen further, the radial flange is supported 18 the outer sleeve 13 axially over a plurality Zentrierku rules 22 on an adjacent end face 23 the output shaft 3 from. In that regard, both the radial flange 18 ( 5 . 6 ) as well as the face 23 the output shaft 3 (not shown here) a plurality of recesses 24 on, in which the centering balls 22 are held positively.

Said recesses 24 expediently have suitable contact surfaces 25 for the centering balls 22 , with a certain opening angle "α", whereby so-called ramps 26 for receiving the respective associated centering balls 22 are formed.

As a result of one on the input shaft 2 acting increased torque, along with a torsion of the torsion bar 9 , allow these ramps 26 an exit of the centering balls 22 at least one of the two mutually corresponding recesses 24 out by the outer sleeve 13 against the spring force of the spring element 14 in the direction of the steering wheel, not shown in detail, accordingly moves in the drawing to the left and starting from the preset basic or neutral position, a relative rotational movement between the input shaft 2 and the output shaft 3 is effected.

The return of the input shaft 2 in said basic or neutral position to the output shaft 3 or the centering of the same takes place under the action of the torsion bar 9 as soon as the increased torque is withdrawn.

In investigations has become for the bearing surfaces 25 In cross-section, an opening angle "α" of 90 ° to 180 ° proved to be particularly useful.

1

steering housing

2

input shaft

3

output shaft

4

Bearing (output shaft 3 )

5

End section (output shaft 3 )

6

steering gear

7

rack

8th

Bearing (input shaft 2 )

9

torsion bar

10

centering

11

inner sleeve

12

rolling elements

12a

Rolling Element

13

outer sleeve

14

Spring element (outer sleeve 13 )

15

ring element

16

seal Housing

17

ring seal

18

Radial flange (outer sleeve 13 )

19

spring element

19a

spring tabs (Inside)

19b

spring tabs (Outside)

20

Radial groove (outer sleeve 13 )

21

Radial groove (inner sleeve 11 )

22

centering balls

23

Face (output shaft 3 )

24

recesses

25

contact surfaces

26

ramps

27

pressure chamber

28

pressure line

"Α"

Opening angle (contact surfaces 25 )

Claims (14)

Servo steering device for motor vehicles, with a steering housing ( 1 ), in which coaxial with each other an input shaft ( 2 ), which is operatively connected to a steering wheel, and an output shaft ( 3 ), which has a pinion end portion ( 5 ), which in turn via a steering gear ( 6 ) is connected to steerable wheels of the motor vehicle, are supported, with a torsion bar ( 9 ), which at one end with the input shaft ( 2 ) and at the other end with the output shaft ( 3 ) is firmly connected to a centering device ( 10 ), which on the one hand define a certain basic position of the input shaft ( 2 ) to the output shaft ( 3 ) and on the other hand, an axial movement of the input shaft ( 2 ), and with a means for applying an external force to the steering device, characterized in that the centering device ( 10 ) an inner sleeve ( 11 ), which from the input shaft ( 2 ) and is connected to the same axially and rotationally fixed, that on the inner sleeve ( 11 ) by means of a plurality distributed over the circumference thereof and radially spring-sprung rolling elements ( 12 ) one in the axial direction against the output shaft ( 3 ) at least spring-loaded outer sleeve ( 13 ) axially displaceable, but is mounted rotationally fixed, and that the outer sleeve ( 13 ) at its to the output shaft ( 3 ) pointing end face a radial flange ( 18 ), which extends axially over a plurality of centering balls ( 22 ) on an adjacent end face ( 23 ) of the output shaft ( 3 ) is supported. Servo steering device according to claim 1, characterized in that the rolling bodies ( 12 ) for torque transmission between inner and outer sleeve ( 11 . 13 ) radially inward of at least one on the inner sleeve ( 11 ) and a spring force in the radial direction on the rolling elements ( 12 ) performing spring element ( 19 ) held in a form-fitting manner and radially outside within a radial groove pointing in the axial direction ( 20 ) of the outer sleeve ( 13 ) are guided. Servo steering device according to claim 2, characterized in that the spring element ( 19 ) by a spring ring with radially inwardly and radially outwardly directed spring tabs ( 19a . 19b ) is formed, wherein the inwardly directed spring tabs ( 19a ) within radial grooves ( 21 ) of the inner sleeve ( 11 ) are fixable, and the outwardly directed spring tabs ( 19b ) of the positive reception of the rolling elements ( 12 ) serve. Servo steering device according to at least one of claims 1 to 3, characterized in that two or more rolling elements ( 12 ) are each combined to form an axially aligned row of rolling elements. Servo steering device according to at least one of claims 1 to 4, characterized in that the inner sleeve ( 11 ) non-positively by press fit and / or material fit, preferably by welding, with the input shaft ( 2 ) is firmly connected. Servo steering device according to at least one of claims 1 to 5, characterized in that the inner and outer sleeves ( 11 . 13 ) are formed as Blechumformteile. Servo steering device according to at least one of claims 1 to 6, characterized in that the outer sleeve ( 13 ) by means of a spring mentes ( 14 ) in the axial direction against the output shaft ( 3 ) is spring loaded. Servo steering device according to at least one of claims 1 to 7, characterized in that the outer sleeve ( 13 ) by means of a pressure medium in the axial direction via the centering balls ( 22 ) against the output shaft ( 3 ) is pressable. Servo steering device according to claims 7 and 8, characterized in that the spring element ( 14 ) in a pressure room ( 27 ) is arranged, which via a pressure line ( 28 ) can be acted upon by a pressure medium and by the outer sleeve ( 13 ) is limited. Servo steering device according to at least one of claims 1 to 9, characterized in that the centering balls ( 22 ) positively in mutually corresponding recesses ( 24 ) of the radial flange ( 18 ) of the outer sleeve ( 13 ) and the adjacent end face ( 23 ) of the output shaft ( 3 ) are held. Servo steering device according to claim 10, characterized in that the recesses ( 24 ) Bearing surfaces ( 25 ) for the associated centering ball ( 22 ) whose opening angle "α" in cross section is 90 ° to 180 °. Servo steering device according to at least one of claims 1 to 11, characterized in that the steering gear ( 6 ) by a rack gear with rack ( 7 ) and connected linkage to the wheels is formed. Servo steering device according to at least one of claims 1 to 11, characterized in that the steering gear ( 6 ) is formed by a ball nut steering with threaded spindle and connected linkage to the wheels. Servo steering device according to at least one of claims 1 to 13, characterized in that the means for applying a External force on the steering device by an electro-mechanical or hydraulic drive is formed.