DE102020206740A1 - Steering system with axially adjustable steering column with steering wheel and steering torque function - Google Patents

Abstract

The invention relates to a steering system with a steering column adjustable in the axial direction with a steering wheel and steering torque function. A steering system according to the invention has a steering column (10) with a steering wheel (12) which is non-rotatably connected to a sleeve (14), with at least one sleeve externally threaded section (20a, 20b) being provided on the sleeve (14) which is connected to a corresponding internal pipe thread section (24) of a pipe (18) surrounding the sleeve (14) on the outside at least in sections. Furthermore, a sleeve internally threaded section (22a, 22b) is provided on the sleeve (14), at least in sections, which engages with a spindle externally threaded section (26) of a spindle (16) which penetrates the sleeve (14) on the inside at least in sections, whereby both the tube (18) and the spindle (16) are fixed, but rotatably mounted. At least one drive element for the tube (18) and / or the spindle (16) is provided and arranged in such a way that a translational movement and / or a rotational movement of the Sleeve (14) with attached steering wheel (12) can be brought about.

Description

The invention relates to a steering system with a steering column adjustable in the axial direction with a steering wheel and steering torque function. A steering torque function is understood to mean, in particular, a force feedback function and / or a steering aid function (servo function).

Steering systems with a force feedback function are particularly suitable for vehicles with steer-by-wire steering systems and / or for vehicles intended for autonomous driving. In this respect, reference is also made to vehicles with such steering systems, in particular to motor vehicles.

Steer-by-wire steering systems are characterized by the fact that a steering command from a steering wheel or another control instrument is passed on electrically to a steering actuator via a control unit or in some other way, which then executes steering commands on steerable wheels of the motor vehicle.

Regardless of whether a steer-by-wire steering system is present or not, a steering wheel is usually mounted on an upper end of the steering column of motor vehicles, which makes it possible to adjust the steering angle of the steerable wheels. In this disclosure, a steering wheel is understood to mean not only circular control wheels, but also differently shaped control elements which are used to adjust the steering angle of the steerable wheels of the motor vehicle. In this respect, reference is also made to rectangular, fork-like and any other shaped control elements that are suitable for setting the steering angle of the steerable wheels and are usually operated with one or two hands. In most cases, the control element has exactly one degree of freedom, usually a rotational degree of freedom, the degree of freedom being used to turn the wheels to the right or left or to reduce a steering angle again in the direction of the neutral position of the wheels.

Autonomous driving of vehicles is likely to come in various forms. This is expressed, among other things, in so-called SAE levels, which describe different degrees of automation. In levels 3 and 4, depending on the driving situation, a driver and thus an operating device for the steering is required. So that the steering wheel does not interfere with autonomous operation, it is advantageous to be able to stow it away or retract it. For stowing by moving in the axial direction, it is advantageous if the steering wheel can be moved a sufficiently large stowage path in the axial direction, in particular by at least 10 cm, preferably at least 15 cm or at least 20 cm and particularly preferably at least 25 cm or at least 30 cm. If a steering wheel stowed in this way is needed again for manual driving, it must be able to be moved out of its stowed position in the axial direction again as quickly as possible in order to be able to be operated by a driver. At least then, a power steering function or steer-by-wire function is also required. This supports the driver or generates a steering torque in steer-by-wire systems and thus gives the driver feedback on the road via the steering wheel. The motor that generates the lane feedback is also known as a force feedback motor and, together with a control unit, forms the force feedback actuator (FFA). The functionality of being able to provide road feedback to a driver via the steering wheel by means of a motor is referred to below as the force feedback function. In the case of steer-by-wire steering systems, because there is no mechanical penetration, it must be possible to generate a counter-torque to mediate the vehicle reaction on the steering wheel. A steering system with a force feedback function must therefore be able to generate moments and steering wheel movements.

the end DE 10 2016 202 465 A1 a motor-adjustable steering column for a motor vehicle is known, which comprises the following elements: a support unit that can be connected to a vehicle body and of which an actuating unit is held, which comprises a steering spindle rotatably mounted in a casing unit about a longitudinal axis, the casing unit having an outer casing tube, in an inner jacket tube is received axially displaceably telescopically in the direction of the longitudinal axis, and with an actuator which is connected to the inner jacket tube and the outer jacket tube and from which the inner jacket tube can be axially pushed in and out relative to the outer jacket tube. For length adjustment, ie for retraction or extension, an electromotive actuator is provided which is designed as a spindle drive and interacts with a spindle nut. A force feedback function is not described.

the end DE 10 2015 224 602 A1 an adjustable steering column for a steer-by-wire steering device of a motor vehicle is known, which comprises the following elements: an actuating unit which comprises a steering spindle rotatably mounted in a casing unit about a longitudinal axis, the casing unit having a first casing tube in which at least one The second casing tube is arranged in a rotationally fixed manner with respect to the longitudinal axis and is telescopically axially displaceable, an actuator being connected to the first and the second casing tube, of which the second casing tube can be axially retracted and extended relative to the first casing tube, and the one spindle drive comprises a parallel arranged to the longitudinal axis, rotatably drivable by an electric servomotor threaded spindle, which is located on a Supports casing tube and which is screwed into a spindle nut which is rotatably attached to the other casing tube. In order to specify a motor-driven steering column that is more suitable for use in steer-by-wire steering systems, the invention proposes that the threaded spindle extends within the first jacket tube, preferably coaxially, and the spindle nut is attached to the second jacket tube, preferably coaxial.

the end DE 10 2019 209 680 A1 an actuator unit for a steering wheel of a vehicle is known. This actuator unit includes a housing, a steering shaft positioned in the housing, an outer end of the steering shaft being connected to the steering wheel. Furthermore, a steering column is provided which comprises an inner tube and an outer tube and is arranged around the steering shaft, the steering column being positioned between the housing and the steering shaft. The actuator unit further comprises an input shaft which is installed in the steering shaft from an inner end, a torsion bar being accommodated in the input shaft. Furthermore, a motor is provided which is mechanically coupled to the input shaft, and an output selection device which is designed to select a tilting movement or a telescopic movement of the steering wheel. In addition, the actuator unit comprises at least two planetary gear sets, a first gear set and a second gear set, which are coupled in a cascade connection and between a rotor shaft of the motor and the input shaft, the at least two planetary gear sets being designed to provide a steering feel torque and / or a tilting movement and / or to transmit a telescopic movement to the steering wheel.

As far as the above-described steering systems known from the prior art have kinematics on which a translational movement for extending and retracting the steering column in the axial direction and a force feedback function are implemented, the functions are separated, whereby these steering systems are relatively have a high number of parts and also a high space requirement.

The invention is based on the object of providing a steering system with an axially adjustable steering column with steering wheel and steering torque function that has only a few elements and requires little space.

The object is achieved according to the invention with the features of claim 1. Further practical embodiments and advantages of the invention are described in connection with the dependent claims.

A steering system according to the invention comprises a steering column with a steering wheel that is rotatably connected to a sleeve, with at least one sleeve outer thread section being provided on the sleeve, which engages with a corresponding pipe inner thread section of a tube surrounding the sleeve at least in sections on the outside. A sleeve internally threaded section is provided on the sleeve, at least in sections, which engages with a spindle externally threaded section of a spindle which penetrates the sleeve at least in sections, both the tube and the spindle being stationary but rotatably mounted. Furthermore, at least one drive element for the tube and / or the spindle is provided and arranged in such a way that both a translational movement and a rotational movement of the sleeve with the steering wheel attached to it can be brought about by driving the tube and / or the spindle. The structural design of a steering system according to the invention makes it possible to implement an axial adjustability of a steering wheel and a steering torque function on a steering wheel in a structurally simple manner. Particular advantages result in particular from the fact that the steering wheel is attached to the sleeve, which interacts via at least one sleeve internally threaded section and at least one sleeve externally threaded section at the same time with an externally adjoining tube and an internally adjoining spindle. This structural design, in conjunction with different drive concepts, enables various steering systems with axial adjustment options and steering torque functions to be implemented, which require relatively few individual elements for the implementation of these functions and which require little installation space. The drive concepts referred to, as well as the drive elements required for them and further structural details will be discussed below in connection with the corresponding dependent claims.

In a particularly practical embodiment, the pipe internally threaded section and the spindle externally threaded section of a steering system according to the invention have threads with different pitches. In this regard, reference is made in particular to the possibility of providing a rather steep thread on one of the pairings of pipe internal thread section with sleeve external thread section or spindle external thread section with sleeve internal thread section and a rather flat thread on the other pairing. By using the steep thread, a high axial travel speed can be generated, while a rather flat thread is better suited for the implementation of the steering torque function in order to generate forces and / or torques - especially precisely metered - to be transmitted to the steering wheel as road feedback.

In a further practical embodiment of a steering system according to the invention, the at least one sleeve externally threaded section and the at least one sleeve internally threaded section are arranged opposite one another at least in sections. Preferably, one or more sleeve outer thread sections and sleeve inner thread sections are arranged exactly opposite one another and preferably extend over the same axial length section of the sleeve. This has the advantage that there is a very good guiding effect and the steering system can be designed in such a way that there is no further adjustment in the axial direction, even with larger adjustment distances, such as at least 15 cm, 20 cm, 25 cm or 30 cm additional guide element is required.

The guiding effect is further improved and the friction of the steering system is reduced if at least two sleeve externally threaded sections spaced apart in the axial direction and / or two sleeve internally threaded sections spaced apart in the axial direction are provided on the sleeve. In this case, the support and guidance takes place over the entire axial length between the first sleeve external thread section and the last sleeve external thread section or between the first sleeve internal thread section and the last sleeve internal thread section (each viewed from the steering wheel in the axial direction along the Sleeve), whereas the friction is reduced to the axial length over which thread engagement actually takes place. For example, a support length of 30 cm can be created by providing two sleeve internally threaded sections and two sleeve externally threaded sections each on opposite sides of a sleeve, each extending over 5 cm, but spaced apart from one another by a distance of 20 cm in the axial direction are.

The overall play in the thread pairing is also reduced by providing a plurality of sleeve external thread sections spaced apart from one another in the axial direction and / or sleeve internal thread sections spaced apart from one another in the axial direction.

It is preferred in terms of manufacturing technology and advantageous in terms of the total weight if the sleeve has a larger diameter than at least one sleeve area adjoining in the axial direction in at least one sleeve thread area extending in the axial direction with a sleeve outer thread section and / or sleeve inner thread section. Preferably, a sleeve thread area with sleeve outer thread section and / or sleeve inner thread section has a thickening that extends radially outward for the sleeve outer thread section and / or a thickening that extends radially inward for the sleeve inner thread section.

In a structurally particularly simple embodiment of a steering system according to the invention, a first motor is provided as the drive element for the tube and a second motor is provided as the drive element for the spindle. Through suitable control of the first motor and the second motor as well as a suitable selection of the direction of rotation, either the steering wheel can only be moved in the axial direction in order to move it translationally between a use position or several use positions and a stowed position, or the steering wheel can - without moving it translationally - a steering torque can be applied in order to transfer a road condition in the form of a steering torque or a steering force to the steering wheel and thus provide a steering torque function, or both functions can be implemented at the same time.

If a first gear is arranged between the first motor and the pipe and / or a second gear is arranged between the second motor and the spindle, particularly simple and, in particular, motors with relatively low power can be used if the desired maximum speed and / or a desired maximum torque is provided with the aid of the first gear and / or the second gear by means of a corresponding translation. In particular, the costs of a steering system according to the invention can be kept low by using standard motors that are already part of a modular system for a large number of motor vehicles and / or are already used in another function in the same motor vehicle.

In another practical embodiment of a steering system according to the invention, the tube and the spindle are coupled to one another via a clutch, with a motor being functionally connected to the transmission. This embodiment has the advantage that the steering system according to the invention can be implemented in a particularly simple and cost-effective manner, since only one motor is required. However, in this embodiment, the axial adjustment function and the steering torque function cannot be implemented at the same time.

In a further practical embodiment of a steering system according to the invention, the tube and the spindle are via a Summing gear functionally connected, wherein at least one first motor is functionally connected to the summing gear. With this embodiment, the same functions can be realized as with the embodiment with clutch described above. However, the embodiment has the advantage that by connecting the summing gear to a second motor and the optional connection of this second motor, an operating mode can also be implemented in which an axial adjustment is carried out while a steering torque function is available at the same time.

• 1 eine erste Ausführungsform eines erfindungsgemäßen Lenksystems in einer schematischen Darstellung mit einem ersten Motor für das Rohr und einem separaten zweiten Motor für die Spindel,
• 2 den mit II gekennzeichneten Bereich aus 1 in einer vergrößerten Darstellung,
• 3 eine zweite Ausführungsform eines erfindungsgemäßen Lenksystems mit nur einem ersten Motor für das Rohr und die Spindel in Kombination mit einer Schaltkupplung und
• 4 eine dritte Ausführungsform einer erfindungsgemäßen Lenksäule mit einem als Hauptmotor dienenden ersten Motor und einem als Hilfsmotor dienenden zweiten Motor in Kombination mit einem Summiergetriebe.

Further practical embodiments of the invention are described below in connection with the drawings. Show it:

• 1 a first embodiment of a steering system according to the invention in a schematic representation with a first motor for the tube and a separate second motor for the spindle,
• 2 select the area marked with II 1 in an enlarged view,
• 3 a second embodiment of a steering system according to the invention with only a first motor for the tube and the spindle in combination with a clutch and
• 4th a third embodiment of a steering column according to the invention with a first motor serving as the main motor and a second motor serving as an auxiliary motor in combination with a summing gear.

1 shows a first embodiment of a steering system with a steering column 10 with a steering wheel 12th that rotates with a sleeve 14th connected is.

As in 2 can be seen are on the sleeve 14th two sleeve externally threaded sections 20a , 20b provided with a corresponding pipe internally threaded section 24 one the sleeve 14th are on the outside in sections surrounding the pipe in engagement.

In 2 it can also be seen that on the sleeve 14th at least two sleeve internally threaded sections 22a , 22b are provided, which with a spindle externally threaded section 26th one the sleeve 14th spindle penetrating in sections on the inside 16 are engaged.

The areas of the sleeve that extend in the axial direction 14th , in which the sleeve externally threaded sections 20a , 20b and the sleeve internally threaded sections 22a , 22b are arranged can generally be referred to as sleeve thread areas. As in 2 can be seen, has the sleeve 14th in the sleeve thread areas with sleeve external thread section 20a , 20b and with sleeve internally threaded section 22a , 22b has an enlarged diameter compared to at least one sleeve area adjoining it in the axial direction, that is to say there are thickenings for the sleeve outer thread sections which each extend outward in the radial direction 20a , 20b and inwardly extending thickenings in the radial direction for the sleeve internally threaded sections 22a , 22b intended.

Here are both the pipe 18th as well as the spindle 16 fixed in a suitable manner, but rotatably mounted (not shown).

As a drive element for the spindle 16 is a first engine 30th provided, between the first motor 30th and the spindle 16 optionally a first transmission 28 is arranged.

As a drive element for the pipe 18th is a second engine 34 provided, being between the second motor 34 and the pipe 18th optionally a second gear 32 is arranged.

When the first gear 28 and / or the second transmission 32 are interposed, can be the first motor 30th and as a second engine 34 relatively compact and / or particularly inexpensive standard motors are used. The one you want on the spindle 16 and / or the pipe 18th The transmitted speed and / or the required torque can then be generated with the aid of a suitable translation or reduction. In the embodiment shown, the respective thread pairings have between tubes 18th and sleeve 14th on the one hand and between the spindle 16 and sleeve 14th different slopes, namely a steeper thread for that of the thread pairings, which for the translational adjustability of the steering wheel 12th is used, and a rather flat thread for the other thread pairing. By means of a control (not shown) that is functional with the first motor 30th and the second motor 34 is coupled, can by driving the tube 18th and / or the spindle 16 a translational movement and / or a rotational movement of the sleeve 14th be effected with attached steering wheel.

In the 3 and 4th further embodiments of steering systems according to the invention are shown, the same reference numerals being used below to describe these embodiments as for the first embodiment, provided that the elements are identical or at least functionally equivalent.

At the in 3 The embodiment shown is the spindle 16 with a first gear 28 coupled while the pipe 18th functional with a clutch 36 connected is. A first motor is used as the drive element 30th functional with the first transmission 28 tied together. With this particularly simple arrangement, which only has one motor 30th requires, a steering system according to the invention can be implemented inexpensively. By switching between two switching states of the clutch 36 can the engine 30th - with a suitably designed gearbox 28 - either for translational movement of the steering wheel 12th or to implement the steering torque function (force feedback function and / or steering aid function or servo function).

At the in 4th illustrated embodiment are the spindle 16 and the pipe 18th functional with elements of a summing gear 38 coupled. Here is the summing gear 38 also with a first motor 30th and an optional second motor 34 coupled.

In this case the first engine is the best option 30th as the main engine, and the second engine 34 as an auxiliary motor that can be switched on if necessary. If only the first engine 30th is used as the main motor (or is provided), either an axial adjustability of the steering wheel can be 12th or the steering torque function can be used. If also the second engine 34 is provided and is switched on, both functions can also be used at the same time, for example to control a steering wheel 12th , which is currently in the stowed position, can be operated by a vehicle driver using a translational method and at the same time already provide the steering torque function in order to give the driver a lane state on the steering wheel while moving from the stowed position to an operating position 12th to be able to report back.

The features of the invention disclosed in the present description, in the drawings and in the claims can be essential both individually and in any combination for the implementation of the invention in its various embodiments. The invention can be varied within the scope of the claims and taking into account the knowledge of the competent person skilled in the art.

List of reference symbols

10

Steering column

12th

steering wheel

14th

Sleeve

16

spindle

18th

pipe

20a, 20b

Sleeve male thread section

22a, 22b

Sleeve internally threaded section

24

Pipe internally threaded section

26th

Spindle male thread section

28

(first) transmission

30th

(first) engine

32

(second) transmission

34

(second) engine

36

Clutch

38

Summing gear

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102016202465 A1 [0006]
• DE 102015224602 A1 [0007]
• DE 102019209680 A1 [0008]

Claims (10)

Steering system with a steering column (10) with a steering wheel (12) which is non-rotatably connected to a sleeve (14), with at least one sleeve externally threaded section (20a, 20b) being provided on the sleeve (14), which is connected to a corresponding tube -Internal threaded section (24) of a tube (18) surrounding the sleeve (14) on the outside at least in sections is in engagement, with an internally threaded section (22a, 22b) being provided on the sleeve (14) at least in sections, which is provided with an externally threaded spindle section (26) a spindle (16) penetrating the sleeve (14) on the inside at least in sections is in engagement, both the tube (18) and the spindle (16) being fixedly but rotatably mounted, with at least one drive element for the tube ( 18) and / or the spindle (16) is provided and arranged in such a way that by driving the tube (18) and / or the spindle (16) a translational movement and / or a rotational movement of the sleeve (14) with it solid steering wheel (12) can be brought about. Steering system according to the preceding claim, characterized in that the pipe internally threaded section (24) and the spindle externally threaded section (26) have threads with different pitches. Steering system according to one of the preceding claims, characterized in that the at least one sleeve outer thread section (20a, 20b) and the at least one sleeve inner thread section (22a, 22b) are arranged at least partially opposite one another. Steering system according to one of the preceding claims, characterized in that at least two sleeve external thread sections (20a, 20b) spaced apart in the axial direction and / or two sleeve internal thread sections (22a, 22b) spaced apart in the axial direction are provided on the sleeve (14) are. Steering system according to one of the preceding claims, characterized in that the sleeve (14) has an opposite sleeve thread section (20a, 20b) and / or a sleeve internal thread section (22a, 22b) in at least one sleeve thread area extending in the axial direction has at least one sleeve area adjoining it in the axial direction of enlarged diameter. Steering system according to one of the preceding claims, characterized in that a first motor (30) is provided as the drive element for the tube (18) and a second motor (34) is provided as the drive element for the spindle (16). Steering system according to the preceding claim, characterized in that a first gear (28) is arranged between the first motor (30) and the tube (18) and / or a second gear is arranged between the second motor (34) and the spindle (16) (32) is arranged. Steering system according to one of the preceding claims, characterized in that the tube (18) and the spindle (16) are coupled to one another via a clutch (36) and a gear (28), a motor (30) being functional with the gear (28) ) connected is. Steering system according to one of the Claims 1 until 7th , characterized in that the tube (18) and the spindle (16) are functionally connected to one another via a summing gear (38), the summing gear (38) being functionally connected to at least one first motor (30). Steering system according to the preceding claim, characterized in that the summing gear (38) is functionally connected to a second motor (34).

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