DE102006003654A1 - Steering shaft for a steering wheel with fixed steering hub and power source - Google Patents

Abstract

The invention relates to an integration or direct connection of an auxiliary power source (6) to a steering hub transmission (2) with countershaft (9) for a steering wheel with a fixed steering hub (3). When using a steering hub gear (3) with countershaft (9) there is anyway a significantly higher rotational speed compared to the rotational movement of the steering ring (1) and the steering gear shaft (5) due to the geometric conditions on the countershaft (9). It is proposed to connect an auxiliary power source (6), for example an electric motor of a power steering system, to this countershaft (9) without the interposition of further speed transmission elements. In this way, a previously customary, separate gear (7) for introducing the auxiliary power into the steering gear shaft (5) can be dispensed with. Furthermore, an arrangement of the auxiliary power source (6) on the countershaft (9) and thus a complete integration of the auxiliary power source (6) in the housing of the steering gear (2) is proposed. In addition to the function of a power steering system, further possible uses of the device according to the invention are mentioned, in which the auxiliary power source (6) applies a torque that is independent of a steering torque applied to the steering wheel rim by a driver, counteracts this and / or generates a haptically perceptible signal on the steering wheel rim .

Description

The The invention relates to a steering shaft for a steering wheel with a fixed Steering hub according to the preamble of claim 1

Previously customary steering wheels for motor vehicles exist usually only from a steering wheel, which by means of spokes is connected to a steering hub, which in turn rotatably with a Steering shaft is connected. As additional Functional elements of these steering wheels are often just buttons for the operation the horn provided, the electrical connection of the horn with fixed vehicle components mostly by simple slip rings is reached. For some years steering wheels are also standard with Airbags equipped, the signal transmission in turn via slip rings, via coil springs or over opto-electrical or induction-based method is performed.

In Lately, in addition Increased additional controls, such as the operation of a car radio a car phone or a multimedia unit, arranged on the steering wheel. This increases both the amount of signals to be transmitted and the requirements to the transmission security and transmission quality. Even though these claims with the means described above are mostly satisfactory Fulfills can be this is associated with a considerable effort.

Steering wheels with co-rotating steering hubs, however, have principle disadvantages. On the one hand, it is not possible to use asymmetric airbags the instantaneous angle of rotation of the steering wheel at the time of release of the Airbags not considered can be and the inherent advantages asymmetrical Airbags could therefore easily turn into their opposite. on the other hand is the integration of displays in the steering hub to simple signal lights and illuminated icons limited because more complex information at more than e.g. 45 ° opposite the Neutral position of the twisted steering wheel hub no longer reliably detected by the driver can be or this in an inadmissible way distract from the traffic.

It were therefore steering wheels developed which over one opposite the vehicle has fixed steering hub. These basically offer the Possibility, both asymmetric airbags to increase occupant safety to use, as well as almost any informational presentations, for example about free to integrate programmable displays into the steering hub. By a suitable construction can also be a direct cable connection between fixed vehicle parts and the fixed steering hub can be made without resorting to coil springs or similar solutions.

From the French patent FR 2 815 318 B1 and the corresponding publications EP 1 199 243 A1 and JP 2002 178 932 A already a fixed steering hub is known. The steering wheel of this steering wheel is connected by means of spokes with a concentrically arranged around the center of the fixed steering hub ring with internal teeth, which meshes with a gear lying therein, which transmits the rotational movement of the steering wheel to a steering gear shaft.

Due to the principle hereby finds a translation the rotational movement of the steering ring in the fast place, whereby the Use of otherwise identical steering shafts and / or steering gear Vehicles with and without fixed steering hub with the same steering behavior not possible is. Besides that is the for a cable feedthrough limited space available for the fixed steering hub, which causes difficulties in the assembly of cables with pre-assembled Can result in plugs.

Also In principle, there is an offset between this solution the center of the turntable and the steering gear shaft. An assistant assistance of the Steering can due to the already cramped space and the arrangement of the components of the steering gear not integrated but must, for example, in the course of the steering gear shaft begin. This is due to the low rotational speeds This wave a correspondingly high, einzuleitendes in the steering gear shaft Torque, creating a regular Intermediate gearbox becomes necessary which additional cost and weight caused and claimed space.

From the French patent FR 2 827 561 B1 a steering wheel is known in which the rotational movement of a steering wheel is transmitted via a hollow shaft to a gear. In the hollow shaft, a fixed, the steering hub bearing axis is mounted, which in turn has a bore through which, for example cables can be passed to the fixed steering hub. The gear of the hollow shaft meshes with the pinion of a countershaft whose second pinion meshes with a gear of the actual steering shaft. The steering shaft is arranged coaxially with the hollow shaft. With such a construction, it is possible to achieve an identical rotational direction of the steering wheel and steering shaft according to the direction of rotation and angle of rotation of the steering wheel and therefore, for example, to use identical steering gear in vehicle equipment with and without fixed steering shaft. However, for a cable bushing to the fixed steering hub for Space available here very limited.

The Canadian patent CA 1 318 833 discloses a similar technical solution, which, however, is characterized by a considerably increased free space for the passage of cables to the fixed steering hub.

Also the German publication DE 37 37 165 A1 and the corresponding European patent application EP 0 314 887 A1 disclose a similar construction and other variants, which are based on the one hand on a spiral for holding the steering hub in the steering wheel, on the other hand on bevel gear on the circumference of the steering hub or on an inclined, rotating on the steering hub wobble.

The mentioned solutions is common that they do not have a power source to support the steering power mention of the driver and thus also no indication of a possible integration of an auxiliary power source with a direct introduction of a moment into a steering-wheel transmission give.

In front In this background, the invention is based on the object Steering shaft for to present a steering wheel with a fixed steering hub, which is through the integration or direct connection of a Power source to a steering knuckle gear features.

The solution This object is apparent from the features of the main claim, while advantageous embodiments and developments of the invention the dependent claims are removable.

Of the Invention is based on the finding that, especially when used a steering gear with countershaft due to the geometric conditions anyway at the countershaft in comparison to the rotary motion of the turntable and the steering gear shaft turning much faster Wave is present, which is therefore excellent for to an auxiliary power source, for example, an electric motor of a Power steering, directly, so without the interposition of other translation elements to join.

Accordingly, the invention is based on a steering shaft for a steering wheel with a fixed steering hub, which is rotatably mounted on a verse with a cable channel Henen hub axle. Essentially concentric to the axis of rotation of the hub axle, a rotatable steering ring is arranged, which is non-rotatably connected to a hub axle receiving and designed as a hollow shaft steering arm shaft. The steering arm shaft has at its end facing away from the steering rim end outer teeth, which is in engagement with a first countershaft pinion. A non-rotatably mounted on the steering arm shaft gear is of course an external toothing equivalent. The first countershaft pinion is rotatably mounted together with a second countershaft pinion on a countershaft against each other. The second countershaft pinion is also engaged with a steering gear shaft gear which is rotatably mounted on a steering gear shaft. Such steering gear transmissions are from the writings DE 37 37 165 A1 . CA 1 318 833 and FR 2 827 561 B1 already known.

to solution the task is an auxiliary power source is provided, which with the countershaft on the one hand and a fixed part on the other connected, and introduce a torque in the countershaft can, which is at least one introduced at the steering wheel steering power supported. at the fixed part may be advantageous to the housing of the Lenknabengetriebes act. In principle, however, everyone is in the Compared to the rotation of the countershaft fixed point suitable.

By the coupling of the power source, in the vast majority make an electric motor will be a power steering, directly to the relative to steering wheel and steering gear shaft fast rotating countershaft, can the usual separate transmission to reduce the speed of the power source and simultaneously increasing the available torque eliminated, and so component and assembly costs saved and the weight and the needed Space of the entire steering device can be reduced. In addition, that can be Speed ratio between slewing ring, countershaft and steering gear shaft by a freely determine appropriate choice of gear pairings within wide limits making it easy is, these ratios so that a desired Power source can be used optimally.

by virtue of the advantages described it is possible and particularly useful the power source directly, ie in the sense of a direct and rigid Coupling with the countershaft to connect. On the other hand can in cases, in which, for example, a selected auxiliary drive via a fixed gearbox has, this also remain on the auxiliary drive, so as for example the Reduce the number of parts to be stocked.

It is also possible that, for example, to enable an emergency operation function with blocked auxiliary power drive a switchable coupling between the power drive and countershaft is inserted. Finally, the circumstances on a vehicle may be such that there is an immediate on Bonding made difficult by a solid coupling of auxiliary power drive and countershaft, for example, for reasons of the available space. In these cases, it is of course possible and useful to place the power drive at a suitable location and to ensure the power transmission through a belt drive, a chain drive, a gear connection or other known means. This may in turn lead to a change in the speed of the auxiliary power drive.

If the power source is an electric motor is an acquisition of existing concepts and control devices for power steering by means of Electric motors with no or minimal changes in control parameters feasible.

With Help the previously described possibilities of speed adjustment The countershaft can usually have the same gear ratio between the speed of the electric motor and the speed of the steering gear shaft be set, in an alternative or previously used variant a steering power assistance is present or has been present. Also in a production of otherwise same vehicle variants without and with fixed steering hub can the electric motor in the first case by means of its own transmission act on the steering gear shaft and in the second case according to the invention on the Counterparts act without any further adjustments in terms of the control or the characteristics of the motor used necessary become.

at particularly heavy vehicles, such as commercial vehicles, it can However, also be useful if the power source is a hydraulic driven motor is. This is especially true when the appropriate Hydraulic lines anyway near the installation of the steering are laid or an alternative vehicle variant without fixed steering hub also by a hydraulically driven engine with auxiliary power is supplied.

The Coupling of the power source to the countershaft is special easily realizable if the power source at one end of the Countershaft is arranged. Here for reasons of to disposal standing space in particular the end facing away from the steering rim the countershaft. In this way, the production is otherwise identical steering shafts in versions with and without steering assistance especially just possible.

One particularly compact steering-column transmission with auxiliary power assistance becomes however possible if the auxiliary power source on the countershaft in the area between the first countershaft pinion and the second countershaft pinion is arranged. Because the length the countershaft mostly due to other factors, such as a required Freedom to lead out of cables from the cable channel of the fixed hub axle, a not used for other purposes between the pinions has, especially space-saving example, an electric motor be placed directly on the countershaft. Whether doing the countershaft itself forms the axis of the auxiliary power drive, or the power drive having a hollow shaft, wel che during assembly rotation with the Countershaft is coupled, in individual cases under consideration to decide the vehicle conditions.

Next the above assumed purpose of the invention, namely the Power Steering in the sense of a usual Power steering, a device according to the invention with the help of a additional Control device used for other purposes advantageous become. In this case, a use of the control device for purposes the power steering assistance Of course not excluded in the sense of a power steering.

Beyond However, advantages arise when a control device based on of sensor data and programs or calculation rules the power source so that it introduces a torque into the countershaft, which of a steering wheel introduced on the steering power in the sense independently is that the steering force applied by the driver is not supported.

It On the one hand this can be an introduction of a torque act without a previous initiation of a steering torque on the steering wheel, on the other hand, but also to initiate a torque, which counteracts the torque exerted by the driver on the steering wheel rim. this makes possible for example, based on appropriate sensor data, the driver a steering direction in complicated parking operations or maneuvering in trailer towing propose. in principle is also an automatic parking or even an automatic steered driving operation of the vehicle conceivable.

For example, in the event of imminent collisions or an imminent agreement of the vehicle from the roadway, the controller may emit signals that cause the power drive to deliver a torque of desired size and direction to the countershaft ent to give either the driver an indication of a required steering correction, or also around the vehicle to steer without driver intervention.

alternative or additionally the controller may be based on environmental Sensor data and programs and / or calculation rules the power source so that it introduces a torque into the countershaft, which results in a haptic perceptible signal on the steering wheel has, without a change of To effect steering direction.

There any torque input by the power source automatically also acts on the steering gear shaft, this is of course so Understand that the steering direction of the vehicle is not for the driver is noticeably influenced. For example, the control device by quickly switching the direction of an initiated Torque a shaking cause the steering wheel, which a driver, for example an impending danger or transgression the permissible or adjusted driving time, but due to the existing elasticities in suspension and inertia of the vehicle not or only insignificantly on the trajectory of the Vehicle affects.

The Invention leaves based on embodiments and further explain a drawing. This one shows

1 a steering shaft with a steering knuckle transmission according to the prior art,

2 a generic steering shaft with a steering knuckle with a countershaft according to the prior art,

3 a steering shaft according to the invention with a steering knuckle transmission according to a first embodiment, and

4 a steering shaft according to the invention with a steering knuckle transmission according to a second embodiment variant.

As already mentioned, shows 1 a steering shaft with a steering knuckle transmission according to the prior art, as similar in the French patent FR 2 815 318 B1 is disclosed.

A fixed steering hub 3 is non-rotatable on a hub axle 26 which defines a cable channel 4 for receiving a fixed steering hub 3 leading cable 15 having. A concentric to the fixed steering hub 3 arranged steering wheel 1 is by means of a steering arm shaft 17 and a steering wheel shaft bearing 18 rotatably mounted and at least one steering wheel spoke 20 with a steering ring with internal teeth 8th rotatably connected, which with a steering gear shaft gear 11 engaged. The rotatably connected to this gear steering gear shaft 5 is about an outside of the steering gearbox 2 arranged worm gear 7 with an auxiliary power source 6 in conjunction, which enables an assistant-assisted steering.

As already explained, takes place in this type of steering gearbox 2 on the one hand inevitably a translation of the rotational movement of the turntable 1 in a rotary motion of the steering gear shaft 5 in the fast, which the use of identical steering gear in vehicle variants with and without fixed steering hub 3 At least seems problematic, since the steering behavior of the vehicle is fundamentally changed.

Further, there is an axial offset between the center of the steering wheel 1 and the steering gear shaft 5 of typically a few centimeters and thus to a shift in the position of the steering wheel relative to an otherwise same vehicle with a steering wheel without fixed steering hub. An integration of a power source 6 in the steering-wheel transmission 2 is not intended and even for reasons of space and lack of appropriate points to initiate a moment hardly possible.

In contrast, shows 2 a generic steering shaft with a steering knuckle transmission 2 , wherein like reference numerals are used here and below for parts having the same function.

The fixed steering hub 3 is in turn rotationally fixed with a hub axle 26 connected, which a - in comparison to the above-explained solution - considerably larger dimensionable cable channel 4 to carry out a fixed steering hub 3 leading cable 15 having. A steering wheel 1 is in turn by means of at least one steering wheel spoke 20 rotatably with a steering wheel shaft 17 connected, which in this case, however, an upper and a lower steering arm shaft bearing 18a respectively. 18b on the hub axle 26 is stored.

In place of an internally toothed ring gear ring, the steering arm shaft 17 an external toothing 10 on, which with a likewise externally toothed upper countershaft pinion 25a combs. The upper countershaft pinion 25a is as well as in this case identical, lower countershaft pinion 25b rotatably on the countershaft 9 fastened, which with the help of countershaft bearings 23a and 23b in the housing of the steering gearbox 2 is stored. The lower countershaft pinion 25b meshes with the steering gear shaft gear 11 , which rotatably on the steering gear wave 5 fixed and by means of the steering gear shaft bearings 19a and 19b is stored.

A steering shaft according to the invention with a steering knuckle transmission according to a first embodiment variant is in 3 shown. In the 2 The device shown here is an auxiliary power source 6 and a controller 27 expanded, which in turn has a database in the form of stored programs, look-up tables and calculation rules, as well as not shown sensors and a power supply, not shown in connection. The drive shaft of the power source 6 is rotatable with one end of the countershaft 9 connected.

The control device 27 regulates the introduction of a torque in the countershaft 9 through the power source 6 , As a result, both a Hilfskraftunterstützung the on the steering wheel 1 by a driver applied steering force in the sense of a classic power steering possible, as well as a correction of the same, a separate steering without the intervention of the driver or the generation of a haptic perceptible on the steering vibration signal.

In the 4 shown second embodiment of the device according to the invention differs from the first embodiment in that the auxiliary power source 6 not at one end of the counter-wave 9 is arranged, where this requires a corresponding space, but space-saving on the countershaft 9 in free space between the two countershaft pinions 25b and 25b is arranged.

1

turntable

2

Steering gear hub

3

fixed steering hub

4

Cabel Canal

5

Steering gear shaft

6

Auxiliary power source

7

worm gear

8th

Turntable ring with internal toothing

9

Countershaft

10

external teeth the steering arm shaft

11

Steering gear shaft gear

12

Not used

13

Not used

14

Not used

15

to fixed steering hub leading electric wire

16

Not used

17

Steering gear shaft

18

Steering arm bearing ( 18a upper bearing; 18b lower camp)

19

Steering gear shaft bearings ( 19a upper bearing; 19b lower camp)

20

Turntable spoke

21

Not used

22

Not used

23

Countershaft bearing ( 23a upper bearing; 23b lower camp)

24

Not used

25

Countershaft pinion ( 25a upper pinion; 25b lower pinion)

26

hub axle

27

control device

Claims (8)

Steering shaft for a steering wheel with a fixed steering hub ( 3 ), which at one with a cable channel ( 4 ) provided hub axle ( 26 ) is mounted rotationally fixed, and with a substantially concentric to the longitudinal axis of the hub axle ( 26 ) and rotatable steering ring ( 1 ), which rotatably with a hub axle ( 26 ) receiving and designed as a hollow shaft steering arm shaft ( 17 ), which at its from the steering wheel ( 1 ) facing away from an external toothing ( 10 ) provided with a first countershaft pinion ( 25a ), which together with a second countershaft pinion ( 25b ) on a countershaft ( 9 ) is arranged against rotation against each other, and in which the second countershaft pinion ( 25b ) with a steering gear shaft gear ( 11 ), which rotatably on a steering gear shaft ( 5 ), Is arranged characterized in that an auxiliary power source ( 6 ) provided with the countershaft ( 9 ) On the one hand and a fixed part on the other hand is connected and a torque in the countershaft ( 9 ), which at least one on the steering wheel ( 1 ) initiated steering power. Steering shaft according to claim 1, characterized in that the power source ( 6 ) directly with the countershaft ( 9 ) connected is. Steering shaft according to one of claims 1 or 2, characterized in that the power source ( 6 ) is an electric motor. Steering shaft according to one of claims 1 or 2, characterized in that the power source ( 6 ) is a hydraulically driven motor. Steering shaft according to at least one of the preceding claims, characterized in that the power source ( 6 ) at one end of the countershaft ( 9 ) is arranged. Steering shaft according to at least one of claims 1 to 5, characterized in that the auxiliary power source ( 6 ) on the counter-wave ( 9 ) in the region between the first countershaft pinion ( 25a ) and the second countershaft pinion ( 25b ) is orders. Method for controlling a steering shaft according to at least one of the preceding claims, characterized in that a control device ( 27 ) based on sensor data and programs or calculation rules, the auxiliary power source ( 6 ) so that this torque in the countershaft ( 9 ), which one of the on the steering wheel ( 1 ) introduced steering force is independent. Method according to claim 7, characterized in that the control device ( 27 ) on the basis of environmental sensor data and programs and / or calculation rules the auxiliary power source ( 6 ) so that this torque in the countershaft ( 9 ) which introduces a tactile signal on the steering wheel ( 1 ) results without causing a change in the steering direction.