This application claims the priority of German patent document 10 2004 020 048.3, filed Apr. 23, 2004 (PCT International Application No. PCT/EP2005/004324, filed Apr. 22, 2005), the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a safety steering column for a motor vehicle.
Safety steering columns, which are common in contemporary motor vehicle engineering, protect a driver of the motor vehicle in the event of an accident by moving out of a hazardous area of the vehicle in an active or passive fashion. In an active safety steering column, this movement is carried out automatically so that the driver normally does not impact against a steering handle which is arranged at an upper end of the steering column. A passive safety column can be moved out of the hazardous area when a predefined force is exceeded; for example an upper steering column part may be mounted so as to be axially displaceable with respect to a lower steering column part.
German patent document DE 101 30 908 A1 discloses a vehicle safety steering column which has a telescopic steering spindle composed of upper and lower spindle parts. It is rotatably mounted in a jacket tube by means of an upper bearing, which supports the upper spindle part on the jacket tube, and a lower bearing, which supports the lower spindle part on the jacket tube. Like the steering spindle, the jacket tube is also formed in a telescopic fashion and has an upper tube part which is near to the steering wheel and a lower tube part which is remote from the steering wheel. Both the spindle parts and the tube parts of the jacket tube are plugged one into the other and can be displaced relative to one another in response to a predetermined axial triggering force. The lower bearing is fixed, while the upper bearing is loose. The two spindle parts or the two tube parts are basically not displaced until the axial triggering force is exceeded, such as, for example, in the event of a crash. In order to adjust the steering column axially, and thus adapt it to individual requirements for a driver, it can be adjusted in its entirety (that is, with the upper and lower spindle or jacket tubes) along a guide.
German patent document DE 102 51 764 A1 discloses a safety steering column of this type, which can be electrically adjusted in the longitudinal and vertical directions. It has a telescopic steering spindle with an upper spindle part near the steering wheel and a lower spindle part remote from the steering wheel. The steering spindle is rotatably mounted in a jacket tube which has an upper tube part near to the steering wheel and a lower tube part remote from the steering wheel. The lower tube part is pivotable about a first axis on a bracket which can be fixed to the vehicle. In addition, an adjustment device, which serves to vertically adjust the jacket tube, has an actuating element pivotably mounted about a second axis on the bracket. The actuating element is coupled in an articulated fashion to a deflector bar mounted on the upper tube part, so as to be pivotable about an axis.
The operation of the adjustment device is similar to that of a toggle lever and is intended to ensure play-free vertical adjustment of the safety steering column, for reasons of comfort among others. The freedom from play of this lever arrangement is important in safety steering columns which can be adjusted by motor, particularly by means of spindle drives, because no separate clamping means are provided for securing the safety steering column in a desired position, such as are used in manually adjustable steering safety columns.
One object of the invention is to provide a safety steering column of the type mentioned above, which has a simple and cost-effective design, and in which the adjustment device is substantially free from play.
This and other objects and advantages are achieved by the safety steering column according to the invention, which comprises a telescopic steering spindle that has an upper spindle part near to the steering wheel and a lower spindle part remote from the steering wheel, and is rotatably mounted in a jacket tube. The jacket tube is also of telescopic design, and has an upper tube part near to the steering wheel and a lower tube part remote from the steering wheel. The lower tube part is pivotably mounted about a first axis, on a bracket which can be arranged fixed to the vehicle.
According to a first embodiment of the invention, the lower tube part can be guided in an axially adjustable fashion in the lower tube part, while in a second embodiment the upper tube part can be guided in an axially adjustable fashion in the lower tube part. The safety steering column also comprises an adjustment device which serves to vertically adjust the jacket tube and has an actuating element which is mounted so as to be pivotable about a second axis on the bracket.
The safety steering column is distinguished by the fact that the actuating element is coupled to the jacket tube by a force transmitting element which can be adjusted in a translatory fashion relative to the jacket tube. Due to the configuration according to the invention, the adjustment device has very little, but still sufficient play to permit the relative movement, necessary as a result of the different movement paths of the jacket tube and the force transmitting element, between these assemblies/parts in the event of a vertical adjustment of the safety steering column.
In a particularly advantageous embodiment of the invention, the force transmitting element can be guided in a guide which is provided on the outside of the jacket tube. Depending on the embodiment of the safety steering column, the guide may be provided either on the upper tube part or on the lower tube part. In this context, the force transmitting element can, for example, be embodied in a manner similar to a sliding block guided in a slot-shaped recess. The embodiment with the force transmitting element which is guided in a guide arranged on the outside of the jacket tube requires only a small installation space. Furthermore, it is possible to mount or guide the force transmitting element and the actuating element virtually without play. As a result, the rigidity of the steering column is enhanced while at the same time susceptibility to vibrations is diminished.
An embodiment of the safety steering column according to the invention in which a first actuating drive is provided for pivoting the actuating element about the first axis, and/or a second actuating drive is provided for longitudinally adjusting the safety steering column, is particularly preferred. Of course, the design of the safety steering column according to the invention may also be used in manually adjustable steering columns in which longitudinal and vertical adjustment are carried out manually by the driver after a clamping device has been released by applying a tensile or compressive force to the steering column or pushing it downward or upward. This permits extensive use of identical parts in the steering columns which can be adjusted by motor/electrically and mechanically in their longitudinal and vertical directions, so that a uniform crash principle can be implemented.
In a further preferred embodiment of the invention, the force transmitting element is formed by an outer tube part in which the upper tube part is guided in an axially adjustable fashion. The upper tube part serves as a guide for the outer tube part so that a particularly simple design of the safety steering column can be implemented. In this second exemplary embodiment of the safety steering column it is also possible for the upper tube part to be guided in an axially adjustable fashion in the lower tube part or alternatively for the lower tube part to be guided in an axially adjustable fashion in the upper tube part.
In the event of a crash, the telescopic steering column according to the invention provides a sufficient deformation path, thereby enhancing the safety of the vehicle. At the same time, the three jacket tube parts which are plugged one into the other permit comfort adjustment while requiring little installation space. Such adjustment allows the a position of the steering handle to be easily adapted to physical requirements of the respective driver. Furthermore, the design, with a total of three jacket tube parts and their play-free mounting one inside the other, increases the rigidity of the steering column, which permits the driving comfort to be increased, for example due to a reduced susceptibility to vibrations.
According to another preferred embodiment of the safety steering column according to the invention, the outer tube part is mounted on the bracket by means of a carriage. The actuating element, which is mounted on the carriage rotatably about a second axis on the outer tube part, so as to be rotatable about a third axis, is arranged between the outer tube part and the carriage. The carriage in turn is arranged in a fixed position on the bracket until misuse forces are overcome, and can be adjusted along its carriage guide when the misuse forces (that is, for example in the event of a vehicle crash) are exceeded. As a result the parts of the safety steering column slide telescopically one inside the other and the steering handle is pulled out of the hazard area of the driver. The actuating element, which is part of the vertical adjustment of the safety steering column, ensures precise positioning and positional fixing of the safety steering column in the desired adjustment position by virtue of its rigid design.
According to an advantageous embodiment of the invention, the actuating element engages around the outer tube part in a U shape. Each of the two arms of the U-shaped actuating element has an L-shaped bent end region, each of which ends is penetrated by the second and third axes. The L-shaped end regions protrude essentially in the orthogonal direction with respect to the U plane, which further increases the rigidity of the actuating element. The actuating element can be made, for example, from plastic or metal, and can thus be manufactured cost-effectively, with precise dimensions.
A first actuating drive is expediently attached to the carriage, and adjusts (by means of a spindle) an actuating arm which is rotationally fixed on the actuating element and thus pivots the safety steering column with respect to the first axis. Spindle drives are proven and precise devices for making adjustments so that the first actuating drive permits precise adaptation of the height of the steering handle by rotating/pivoting the safety steering column about the first axis. Furthermore, such a spindle drive is simple and cost effective to manufacture and requires little maintenance during operation. Depending on the height of the thread on the spindle, the height of the safety steering column or the steering handle can also be adjusted precisely in very small steps.
According to a further advantageous embodiment of the safety steering column, a second actuating drive which adjusts the upper tube part axially with respect to the outer tube part is attached to the outer tube part. The second actuating drive can also be operatively connected to the upper tube part by means of a spindle drive so that longitudinal adjustment is also easily possible. It is also possible for the first and second actuating drives to have an identical or comparable design which allows the variety of parts to be reduced and thus the production costs to be lowered.
According to one particularly preferred embodiment of the invention the first and/or second actuating drives have an electric motor. Electric motors are conceivable in virtually any desired embodiment and can be adapted precisely to respective requirements. Furthermore, electric motors permit low-maintenance operation, are cost-effective to manufacture and have a long service life due to high production quality nowadays.
In a further advantageous embodiment of the invention, a pressure element which presses the lower tube part radially against the upper tube part and thus presses the lower and upper tube parts radially against the outer tube part, is provided on the outer tube part. The pressure element is embodied, for example, as a spring or as a screw element, and ensures play-free bearing of the individual tube parts one in the other. At the same time, it makes the safety steering column rigid, thereby improving overall driving comfort.
To summarize, it is to be noted that all the representative embodiments of the safety steering column according to the invention involve the general idea of permitting both a simplified telescopic capability and a high degree of axial deformation in the event of a crash, in a safety steering column for a motor vehicle having a telescopic steering spindle which is mounted in a telescopic jacket tube.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
In the drawings, identical reference symbols relate to identical or functionally identical or similar components.
According to
The safety steering column 1 is usually installed in a motor vehicle and is mounted by means of a guide on a bracket 9 which is fixed to the vehicle. In order to vertically adjust the safety steering column 1 and a steering handle (not illustrated) arranged at the end of the upper spindle part 3, the lower tube part 7 is mounted pivotably about a first axis 10 on the bracket 9. At the same time, the lower tube part 7 is guided in an axially adjustable fashion in the upper tube part 6 (cf.
The outer tube part 8 is mounted on the bracket 9 (which is fixed to the vehicle), by means of a carriage 11 which, in a comfort position, is arranged in a fixed position on the bracket 9. When misuse forces are exceeded (for example in the event of a crash), it is moved into a crash position in which it can be adjusted parallel to the axis of the safety steering column 1 (cf.
An actuating element 12 is arranged on the outer tube part 8 and the carriage 11. It is mounted on the carriage 11 rotatably about a second axis 14, and on the outer tube part 8 rotatably about a third axis 13. The first axis 10, the second axis 14 and the third axis 13 all run parallel to one another here. The actuating element 12 is part of an adjustment device for vertically adjusting the jacket tube 5, on which further details will be given below.
The actuating element 12 is U shaped and engages around the outer tube part 8 with two arms of the U shape. According to
According to
The transmission of force from the first actuating drive 15 to the jacket tube 5 for the purpose of vertically adjusting the safety steering column 1 (that is, for pivoting the jacket tube 5 about the first axis 10) is carried out by pivoting the actuating element 12 about the second axis 14. Such pivoting causes the force transmitting element 33, which is formed by the outer tube part 8 and in which the upper tube part 6 is guided (preferably, with only a small degree of play) to be displaced. In the process, the force transmitting element 33 applies an actuating force to the upper tube part 6, causing the jacket tube 5 to pivot about the axis 10. In the process, the tubular force transmitting element 33 permits a relative movement of the upper tube part 6 with respect to the force transmitting element 33 in the direction of the longitudinal center axis of the jacket tube. Such movement is necessary, because the upper and lower tube parts 7 and 6 pivot about the first axis 10, while the outer tube part 8 pivots the force transmitting element 33 about the second axis 14.
Due to the relative movement of the upper tube part 6 with respect to the force transmitting element 33, the point of action of the force transmitting element 33 on the jacket tube also migrates back and forth in the axial direction with respect to a reference point on the jacket tube. In context with the present invention, the term “point of action of force” of course also means a bearing face/a contact region between the force transmitting element and the jacket tube.
The radial play between the outer tube part 8, the force transmitting element 33 and the upper tube part 6 guided therein is preferably very small, providing a steering column with a high degree of rigidity. The safety steering column 1 has, inter alia, a simple design due to the simple lever arrangement, composed of the U-shaped actuating element 12 in this exemplary embodiment.
Furthermore, a second actuating drive 18 is attached to the outer tube part 8, and axially adjusts the upper tube part 6 with respect to the outer tube part 8. A first possible end position of a longitudinal adjustment of the upper tube part 6 is shown in
An adjustment mechanism can be provided with respect to the first actuating drive 15 in an analogous fashion, for example by means of a spindle drive. The second spindle drive 18 thus permits longitudinal adjustment of the safety steering column 1 and thus adaptation of the distance of a steering wheel from a driver as well as adaptation to its physiological requirements. The second actuating drive 18 can be connected by a clip 19 (cf.
In order to reduce the risk of injury to the driver in the event of a crash due to an impact of said driver against the steering handle, when a crash occurs or when misuse forces are exceeded, the safety steering column 1 can be moved into a crash position which is shortened significantly in the axial direction compared to the comfort position, and thus moves the steering handle out from the immediate hazardous region in the direction of a dashboard.
For this purpose, the carriage 11 is configured such that, in the event of a crash it is adjusted along its carriage guide with respect to the bracket 9, shortening steering column 1 by telescoping of the individual tube parts 6, 7, 8. Such a shortened safety steering column 1 is shown in
In order to ensure, in the comfort position (
To summarize, in the safety steering column 1 described with reference to
The force transmitting element 33 (by which the actuating element 12 mounted on the carriage 11 so as to be rotatable about the second axis 14 is coupled to the jacket tube 5) is formed by a guide element 35. The latter is similar to a sliding block, and is mounted so as to be rotatable about the third axis 13 on the U-shaped actuating element 12. It is guided with minimal play in a slit-shaped recess 37 in a guide 39. The recess 37 runs parallel to the longitudinal center axis of the safety steering column 1.
In this embodiment, the guide 39 is attached to the outside of the upper tube part 6. When the upper tube part 6 is displaced axially by the second actuating drive 18, the guide 39 can likewise be moved along in the axial direction of the steering column 1 for the purpose of longitudinal adjustment of the safety steering column. The guide 39 has a U-shaped profile, of which only one of the arms 41 and a wall 43 (which connects the arms to one another) can be seen in the illustration in
At least in the position of the safety steering column 1 illustrated in
As is apparent from
The safety steering column 1 which is described with respect to
Due to the small amount of play between the individual components of the longitudinal and vertical adjustment device there is no need for additional, manual clamping means for securing the safety steering column 1 in any desired position without play. The safety steering column 1 is secured exclusively by coupling the first and second actuating drives 15 and 18 in the way described above.
The exemplary embodiments of the safety steering column 1 described with reference to
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
Number | Date | Country | Kind |
---|---|---|---|
10 2004 020 048.3 | Apr 2004 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP2005/004324 | 4/22/2005 | WO | 00 | 10/30/2007 |