WO2013075960A2

WO2013075960A2 - Steering centring means

Info

Publication number: WO2013075960A2
Application number: PCT/EP2012/072347
Authority: WO
Inventors: Michael Hägele; Stefan Häussler
Original assignee: Zf Lenksysteme Gmbh
Priority date: 2011-11-25
Filing date: 2012-11-12
Publication date: 2013-05-30
Also published as: WO2013075960A3; DE102011055734A1

Abstract

The description comprises a steering gear for a vehicle comprising: a first means (5) for displacing a steering rod (1, 4) of the vehicle, wherein the first means (5) can be connected to the steering rod (1, 4), and a spring (2) for restoring the steering rod (1, 4), wherein the steering gear comprises a first driver (11) for compressing the spring (2) in a first direction to the spring centre and the first means (5) comprises a second means (10) for driving the first driver (11) to the spring centre.

Description

Lenkungszentrierung

DESCRIPTION FIELD OF THE INVENTION

The present invention relates to a steering gear for a vehicle and a steering system for a vehicle. BACKGROUND OF THE INVENTION

In the prior art steering systems are known with a provision of a tie rod, the provision is automatic, as soon as a driver of the vehicle lets go of the steering wheel.

SUMMARY OF THE INVENTION

It is required by law that a steering system must have an automatic reset. If the driver releases the steering wheel while driving, therefore, the wheels must automatically be aligned parallel to the vehicle. If the steering system has steering assistance and the steering assistance fails, there is always the danger that a failed steering assistance motor / servomotor will block the steering and prevent the required automatic reset. It is therefore in a steering with steering assistance Required that an additional device is arranged on the steering system, which ensures a provision of the wheels. Such a device should if possible have only a small space requirement in order to be able to obtain an overall large passenger interior. In particular, a steering gear having an additional Liehe device for recovery, should comply with a predetermined restriction of an axial extent (spatial extent in the direction of a wheel axis or parallel thereto). Otherwise, the tie rod or the tie rods would have to be chosen relatively short, which would result in greater sweep and deflection angle, which in turn would produce greater lateral forces on a rack.

It is therefore an object to provide a steering gear which, in a power steering, ensures that the wheels are returned if the driver releases the steering wheel while driving. In addition, the steering gear according to the invention should have the smallest possible space requirement.

As a first embodiment of the invention, a steering gear for a vehicle is provided, comprising: a first means for displacing a tie rod of the vehicle, wherein the first means is connectable to the tie rod and a spring for returning the tie rod, wherein the steering gear has a first Mit - Receiver for upsetting the spring in a first direction to the center of the spring and the first means comprises a second means for carrying the first driver to spring center.

The steering gear according to the invention has only one spring, which is arranged centrally in a steering gear housing, resulting in a simple space-saving design. This centrally located spring serves to return deflections in two directions, resulting in a construction with little axial expansion. Furthermore, the proposed solution does not require a pneumatic or hydraulic system, which also results in a structurally simple construction. wise results. The spring center is a plane formed symmetrically between the axial, outer ends of the spring.

As a second embodiment of the invention, a steering system for a vehicle is provided, comprising a steering gear according to one of claims 1 to 12.

Exemplary embodiments are described in the dependent claims.

According to an exemplary embodiment of the invention, a steering gear is provided, wherein the first driver has a recess for driving the spring. A bulge, which is suitable for driving a spring, represents an embodiment which can be obtained by mechanical deformation, for example cold forming, of the driver in a simple and therefore cost-effective manner.

In a further embodiment of the invention, a steering gear is provided, wherein the bulge is disposed at an outer end of the first driver.

By arranging the bulge at the outer end, a spring can be used in full length, without the need for a very long execution of the driver is required.

According to a further embodiment of the present invention, a steering gear is provided, wherein the first driver comprises a third means, wherein the third means with the second means in a movement of the first means to the spring center is detachably connectable. By providing means that can be coupled in a direction of movement and produce no connection in an opposite direction, a driver can be taken in a simple manner by an axial movement of a rack whose movement can lead to a compression of a spring.

According to an exemplary embodiment of the invention, a steering gear is provided, wherein the first driver is sleeve-shaped and wherein the bulge is annular outwardly and / or the third means is annular inwardly, or wherein the third means is a crank.

A sleeve-shaped design of a driver with annular attachments, for example bulges out of the center of the driver out or Kröpfun- gene can be obtained by simple mechanical deformation, such as cold forming, whereby the manufacturing cost of a driver can be kept low.

In a further embodiment of the invention, a steering gear is provided, wherein the steering gear comprises a second driver for compressing the spring in a second direction to the center of the spring, wherein the second direction is opposite to the first direction.

By the arrangement of two drivers can be a provision of the tie rod in both axial directions of a rack.

According to a further embodiment of the present invention, a steering gear is provided, wherein upon movement of the first driver to the spring center for compressing the spring, the second driver on the Lenkgetrie- begehäuse abuts. The steering gear housing is a fixed reference point for the steering centering, or for the centering of the rack, is. If a first driver in use and upsets the spring and therefore moves a first side of the spring, the second driver is located on the steering gear housing and thus holds the other side of the spring, which in the first place can build up a spring force of the spring to the provision.

According to an exemplary embodiment of the invention, a steering gear is provided, wherein the first means is a rack, a piston rod or a spindle and / or the second means is a snap ring, a crimp ring or a snap ring.

In a further embodiment of the invention, a steering gear is provided, wherein the spring is a single spring or wherein the spring comprises two, three, four or any number of spring elements arranged one behind the other, or wherein the spring is two, three, four or arbitrary includes many spring elements that are directly adjacent. The spring may consist of only a single spring element or be composed of a plurality of spring elements which lie directly against each other or by separating elements, such as washers, are separated and thereby at least directly adjacent. As a result, the spring can be assembled or assembled in any manner, so that the best possible or most cost-effective variant can be selected. By a closed arrangement of the spring or the spring elements, a localized formation of the spring formation can be achieved, whereby the space required for the spring formation can be kept small. According to an exemplary embodiment of the invention, a steering gear is provided, wherein the spring comprises two, three, four or any number of spring elements which are arranged side by side or in parallel. By a parallel arrangement of spring elements, an axial extent of the steering center or the steering gear can be kept small and yet a high spring force due to the parallel connection of a plurality of spring elements can be generated. According to an exemplary embodiment of the invention, a steering gear is provided, wherein the spring is biased.

By biasing the spring, a high spring force of the spring can be generated even with small steering deflections, whereby a full center centering of the rack or a complete Steeringzentrierung can be achieved until full recovery of the steering system and parallel position of the wheels.

In a further embodiment of the invention, a steering gear is provided, wherein the spring is biased such that a complete

Centering of the first means even with necessary overcoming frictional forces, is possible.

A bias of the spring to the extent that any existing frictional forces of the steering system can be overcome, ensures a complete centering or steering centering or provision.

As an idea of the invention, it may be considered to provide a steering gear which, as part of a power steering, provides for the recovery of the wheels of the vehicle as soon as the driver releases the steering wheel. A provision, even at Failure of an electric motor for steering assistance is achieved according to the invention by a spring, wherein the spring is disposed within a steering gear housing. The spring is clamped by an axial movement of a rack counter to the direction of movement. To clamp the spring drivers can be used, which are arranged on the rack.

Of course, the individual features can also be combined with each other, which can also be partially beneficial effects that go beyond the sum of the individual effects.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and advantages of the invention will become apparent from the embodiments illustrated in the drawings. Show it

FIG. 1 shows a steering system with a spring for centering,

Figure 2 shows the spring of Figure 1 in a detailed view. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Figure 1 shows a part of a steering system with a two-part tie rod 1, 4 and a rack 5, wherein the rack 5 by a feed gear 7 along its longitudinal axis in the axial direction is displaceable. The two tie rods

1, 4 are connected by means of ball joints with the rack 5. The feed gear 7 and the gear housing 6 are stationary with respect to the axial movement of the rack 5. Within the gear housing 6, a spring 2 is arranged, which may be designed as a compression spring. The rack 5 may have retaining rings, the driver 11, 12 in an axial movement of the rack 5 in Direction of the center of the spring 2 can take. In this way, a spring force can be generated during an axial movement of the rack 5, which leads to a restoring force. FIG. 2 shows a detail of FIG. 1 in detail. Shown are two drivers 11, 12 which can be moved by an axial movement of the rack 5 to the center of the spring 2. This means that the driver 11 can be moved to the right and the driver 12 can be moved to the left. Movement of the driver 11 to the left is precluded by a securing ring 8 fastened to the steering gear housing 6. A movement of the driver 12 to the right is excluded due to the surface 9 of the steering gear housing 6. In an axial movement of the driver 11, 12, ie a movement of the driver 11, 12 along the longitudinal axis of the rack 5, the spring 2 is entrained and thereby compressed. This results in a spring force, which is directed against the direction of axial movement. If the driving force for the rack 5 is omitted, this spring force can act as a restoring force. Instead of a surface 9 of the steering gear housing 6 as a stop for the driver 12 and a further locking ring or a nut can be used. Instead of a securing ring 8, a surface of the steering gear housing 6 or a nut can be used. The drivers 11, 12 may bulges 13, 14, for example, at their outer ends, which engage in the spring 2 and take along the ends of the spring 2, thereby achieving a compression of the spring 2 can. The rack 5 may have securing rings 10, 16 or locking pins, which in an axial movement of the rack 5 in one direction take the carriers 11, 12 and in an opposite direction of movement no movement of the driver 11,

12 initiate. If the rack 5 moves to the right, the driver 11 is moved by the securing ring 10 to the right. The bulges 13 also move to the right and compress the spring 2 to the right. If the rack 5 is moved to the left, the retaining rings 10 move within a free space 15 and a take away of the driver 11 does not take place. Is the moving? Rack 5 to the left, so the locking ring 16 takes the driver 12 to the left and the bulges 14 of the driver 12 compress the spring 2. If the rack 5 moves to the right, the locking ring 16 moves in the free space 15 and neither the driver 12 yet the spring 2 are taken or compressed.

The spring 2 can be biased, whereby the spring 2 is arranged within the steering gear housing with a tension. By a bias of the spring 2, a high spring force is already generated even with small steering deflections or axial displacements of the rack 5, which ensures a Lenkungszentrierung center or centering when eliminating the drive of the rack 5.

It should be noted that the term "comprising" does not exclude other elements or method steps, just as the term "a" and "an" does not exclude multiple elements and steps.

The reference numerals used are for convenience of reference only and are not to be considered as limiting, the scope of the invention being indicated by the claims.

LIST OF REFERENCE SIGNS

1 tie rod

2 spring

3 storage

4 tie rod

5 rack

6 steering gear housing

7 feed gear

8 circlip

9 area of the steering gear housing

10 circlip

11 drivers

12 drivers

13 bulge

14 bulge

15 free space

16 circlip

17 means of transport

18 means of transport

Claims

A steering gear for a vehicle comprising:

a first means (5) for displacing a track rod (1, 4) of the vehicle, the first means (5) being connectable to the track rod (1, 4) and a spring (2) for returning the track rod (1, 4) .

characterized in that

the steering gear comprises a first driver (11) for compressing the spring (2) in a first direction to the center of the spring and the first means (5) comprises a second means (10) for carrying the first driver (11) to the center of the spring.

2. Steering gear according to claim 1, characterized in that the first driver (11) has a bulge (13) for driving the spring (2).

3. Steering gear according to claim 2, characterized in that the bulge (13) is arranged at an outer end of the first driver (11).

4. Steering gear according to one of the preceding claims, characterized in that the first driver (11) comprises a third means (17), wherein the third means (17) with the second means (10) during a movement of the first means (5). releasably connectable to the spring center.

5. Steering gear according to one of claims 2 to 4, characterized in that the first driver (11) is sleeve-shaped and wherein the bulge (13) is annular to the outside and / or the third means (17) is annular inwardly formed or wherein the third means (17) is a crank.

6. Steering gear according to one of the preceding claims, characterized in that the steering gear has a second carrier (12) for compressing the spring in one second direction to the spring center, wherein the second direction is opposite to the first direction.

7. Steering gear according to claim 6, characterized in that during a movement of the first driver (11) to the spring center for upsetting the spring (2), the second

Driver (12) on the steering gear housing (6) is applied.

8. Steering gear according to one of the preceding claims, characterized in that the first means (5) is a rack, a piston rod or a spindle and / or the second means (10) is a locking ring, a squeezing ring or a snap ring.

9. Steering gear according to one of the preceding claims, characterized in that the spring (2) is a single spring or wherein the spring (2) comprises two, three, four or any number of spring elements which are arranged one behind the other, or wherein the spring ( 2) comprises two, three, four or any number of spring elements which are directly adjacent.

10. Steering gear according to one of the preceding claims, characterized marked, that the spring (2) comprises two, three, four or any number of spring elements which are arranged side by side or in parallel.

11. Steering gear according to one of the preceding claims, characterized in that the spring (2) is biased.

12. Steering gear according to claim 11, characterized in that the spring (2) is biased such that a full centering of the first means (5) is possible even with necessary overcoming frictional forces.

13. steering system for a vehicle comprising a steering gear according to one of the preceding claims.