CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority to and benefits of Chinese Patent Application No.

201010515171.X filed with SIPO on October 22, 2010, the entirety of which is hereby incorporated by reference.

BACKGROUND TECHNICAL FIELD

The present invention relates to an automatic adjustment apparatus for steering wheel.

DESCRIPTION OF THE RELATED ART

The steering wheel automatic adjustment has been widely applied to the vehicle. For the steering wheel with a manual adjustment function to the steering wheel with a memory function and automatic adjustment function, the structure design of the adjustment apparatus for steering wheel is the emphasis of realizing adjustment functions. The structure of the automatic adjustment apparatus for steering wheel may directly affect the production cost, operational stability and safety. With high requirements of the vehicle performance, considering the safety and machinability of the multi-function system of the vehicle and the production cost of the automobile enterprise, the structure of the automatic adjustment apparatus is developing towards simplicity, ease realization, high safety and low cost.

The conventional automatic adjustment apparatus for steering wheel has a complicated structure and the control process thereof is excessively complicated and tedious.

SUMMARY

In order to solve at least one of the above problems in the prior art, the present invention provides an automatic adjustment apparatus for steering wheel with a simple structure.

An automatic adjustment apparatus for steering wheel according to embodiments comprises an assembly frame having a via hole therein; a front column adapted to couple to a steering wheel; a rear column assembly adapted to couple to a steering gear, the rear column assembly being extended through the via hole so as to couple to the front column via a universal join; a first power unit mounted onto the assembly frame and comprising a first step motor, a first screw connected to the first step motor and a first slide block threadedly connected to the first screw so as to slide along the first screw by rotation of the first screw; a second power unit mounted onto the assembly frame and symmetrical with the first power unit about a center of the via hole, the second power unit comprising a second step motor, a second screw connected to the second step motor and a second slide block threadedly connected to the second screw so as to slide along the second screw by rotation of the second screw; a second column configured to drive the rear column assembly to extend and retract in an axial direction thereof; and a connection member having a connection hole, in which the front column is extended through the connection hole so as to connect to the universal join, and the first slide block, the second slide block and the second column are pivotally connected to the connection member respectively.

With the automatic adjustment apparatus according to embodiments of the present invention, the first and second screws and the first and second guide blocks are driven via the first and second step motors respectively, thus achieving the extending and retracting and/or tilting (swing) of the connection member to adjust the steering wheel conveniently. The steering wheel of a vehicle may be adjusted by only control two step motors, so that the structure of the automatic adjustment apparatus and the control thereof are simple and ease to realize.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of the invention will become apparent and more readily appreciated from the following descriptions taken in conjunction with the drawings in which:

Fig. 1 is a schematic view of an automatic adjustment apparatus for steering wheel according to an embodiment of the present invention.

Fig. 2 is a partial section view of the automatic adjustment apparatus of Fig. 1.

Fig. 3 is a schematic view of the connection member and the slide blocks of Fig. 1.

Fig. 4 is a schematic view of an automatic adjustment apparatus for steering wheel according to another embodiment of the present invention.

Fig. 5 is a schematic view of the limit bolt and the second column of Fig. 4. DETAILED DESCRIPTION

Reference will be made in detail to embodiments of the present invention. The embodiments described herein with reference to drawings are explanatory, illustrative, and used to generally understand the present invention. The embodiments shall not be construed to limit the present invention. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions.

In the description, Unless specified or limited otherwise, relative terms such as "central", "longitudinal", "lateral", "front", "rear", "right", "left", "inner", "outer", "lower", "upper", "horizontal", "vertical", "above", "below", "up", "top", "bottom" as well as derivative thereof (e.g., "horizontally", "downwardly", "upwardly", etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the present disclosure be constructed or operated in a particular orientation.

Terms concerning attachments, coupling and the like, such as "connected" and "interconnected", refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.

An automatic adjustment apparatus for steering wheel according to an embodiment of the present invention will be described blow.

As shown in Figs. 1 to 3, the automatic adjustment apparatus for steering wheel comprises an assembly frame 21, a front column 1, a rear column assembly, first and second power units, a second column 18, and a connection member 3.

The assembly frame 21 is formed with a via hole therein. The front column 1 is adapted to couple to the steering wheel (not shown) of a vehicle and the rear column assembly is adapted to couple to a steering gear (not shown) of the vehicle. The rear column assembly is extended through the via hole so as to couple to the front column 1 via a universal joint 14.

The first power unit and the second power unit are mounted onto the assembly frame 21 and symmetrical with each other about a center of the via hole.

The first power unit comprises a first step motor 8, a first screw 12 connected to the first step motor 8 and a first slide block 13 threadedly connected to the first screw 12 so as to slide along the first screw 12 by rotation of the first screw 12.

The second power unit comprising a second step motor 24, a second screw 17 connected to the second step motor 24 and a second slide block 15 threadedly connected to the second screw 17 so as to slide along the second screw 17.

The connection member 3 is formed with a connection hole. The front column 1 is extended through the connection hole and connected to the universal joint 14.

The first slide block 13, the second slide block 15 and the second column 18 are pivotally connected (hinged) to the connection member 3 respectively, and the second column 18 drives the rear column assembly to extend and retract in an axial direction of the second column 18.

In some embodiments, as shown in Figs. 1 and 2, the first step motor 8 and the second step motor 24 are symmetrically mounted onto the assembly frame 21. The first screw 12 and the second screw 17 are also mounted onto the assembly frame 21 for example by bearings 10 respectively.

In some embodiments, the rear assembly frame comprises a first column 11 and a third column 19 which are connected to each other via a spline joint.

The spline joint between the first column 11 and the third column 19 may form a power transmitting path for the steering wheel. When adjusting the steering wheel, the first column 11 and third column 19 may slide relative to each other to achieve the extending and retracting and /or tilting (swing) of the connection member 3, thus realizing the adjustment of the steering wheel.

In alternative embodiments, the first column 11 and the third column 19 may be connected with other means, such as a slide member, and the slide member may allow relative movement between the first column 11 and the third column 19. The slide member may be manufactured by plastic or other materials allowing the relative movement such as telescopic movement between the first column 11 and the third column 19.

The first screw 12 and the first slide block 13 may be connected to each other via trapezoidal threads, that is, the first screw 12 and the first slide block 13 are connected to each other by trapezoidal threaded connection, for example, the first screw 12 may be formed with a male trapezoidal thread and the first slide block 13 may be formed with a female trapezoidal thread engaged with the male trapezoidal thread. Also the second screw 17 and the second slide block 15 may be engaged via trapezoidal threads. Due to the trapezoidal threads, the first screw 12 and the first sidle block 13 have an interlocking function, and the second screw 17 and the second slide block 15 also have an interlocking function. In other words, the trapezoidal threaded connection has a self-locking function.

When finishing the adjustment of the steering wheel, the first and second step motors 8, 24 stop. Because of the trapezoidal thread, the first screw 12 and the first sidle block 13 are interlocked and the second screw 17 and the second slide block 15 are interlocked, so that the front column 1 can't move any more, thus improving safety of the steering wheel effectively.

In some embodiments, the second column 18 has a hollow structure, that is, the second column 18 has an axial hole. The first column 11 is extended through the axial hole and mounted in the axial hole via a bearing 16. A step is formed in the axial hole (i.e. the inner wall of the second column 18) for stopping the bearing 16 disposed between the step and the universal joint 14.

The bearing 16 is disposed between the step and universal joint 14 and stopped by the step. When the connection member 3 is driven to extend and retract, the driving power of the connection member 3 may be transmitted to the first column 11 via the second column 18, the step and the bearing 16, to cause the first column 11 and third column 19 to slide relative to each other.

In some embodiments, as shown in Fig. 3, the connection member 3 comprises a top wall and two sidewalls 31 connected to the top wall and symmetrical with each other, so that the connection member 31 has a substantially U-shape. The connection hole is formed in the top wall. Each of the two sidewalls 31 has a hinge hole 34. The second column 18 is pivotally connected to connection member 3 via the hinge holes 34 in the two sidewalls 31. Each of the two ends (the upper and lower ends in Fig. 3) of each sidewall 31 has a projecting lug 32, and the projecting lug 32 has a waist-shape hole 33. More particularly, the first and slide block 13 has pivot holes on the right and left sides thereof corresponding to the waist-shape holes 33 respectively, and the first slide block 13 and the second slide block 15 are hinged to the connection member 3 via the waist-shape holes 33 and the pivot holes respectively.

In the embodiment of the present invention, the two sidewalls 31 is symmetrically connected to the top wall, for example, the two sidewalls 31 is connected to the right and left ends (see Fig. 3) or the upper and lower ends of the top wall.

In some embodiments, the top wall and the two sidewalls 31 may be connected by various means such as welding. Preferably, for convenient machining, the top wall and the two sidewalls 31 may be formed integrally.

In some embodiments, the projecting lug 32 may be connected to the sidewall 31 via various means such as welding and bolt connection. Preferably, the projecting lug 32 and the side wall 31 may be formed integrally.

In order to control the power transmission better, the connection line between centers of two waist-shape holes 33 on the sidewalls 31 on the same side is consistent with a length direction (the up and down direction in Fig. 3) of the corresponding waist-shape hole 33. Preferably, the hinge hole 34 is on the corresponding connection line. In other words, as shown in Fig. 3, the left pivot point between the second column 18 and the connection member 3, the left hinge hole 34, two left waist-shape holes 33 and two left pivot holes are one the same line, the left pivot point between the second column 18 and the connection member 3, and the right hinge hole 34, two right waist-shape holes 33 and two right pivot holes are one the same line, so that the forces acting on the second column 18 are balanced.

When the connection member 3 tilts, the first and second slide blocks 13, 15 slide on the first and second screws 12, 17 (the two screws are parallel to each other) respectively. The spacing between the two first and second slide blocks 13, 15 may change slightly, because the first and second slide blocks 13, 15 can only slides straightly along the first and second screws

12, 17 respectively, so that the connection member 3 hinged to the first and second slide blocks

13, 15 should be designed to be adapted to the change of the spacing between the first and second slide blocks 13, 15, for this purpose, the waist-shape hole 33 is formed in the projecting lug 32.

As described above, the first and slide block 13 has pivot holes on the right and left sides thereof corresponding to the waist-shape holes 33 respectively, and the connection line between centers of two left pivot holes of the first and second slide blocks is consistent with the length direction of the left waist-shape holes 33, and the connection line between centers of two right pivot holes of the first and second slide blocks is consistent with the length direction of the right waist-shape holes 33. Therefore, when the connection member 3 tilts or swing under the driving of the first and second slide blocks 13, 15, the first and second slide blocks 13, 15 may slide along the length direction of the waist-shape holes 33, so as to control the steering wheel to move backward and forward better.

For controlling the power transmission better, the two waist-shape holes 33 in two projecting lugs 32 at the same side have corresponding positions, that is, the positions of the two upper waist-shape holes 33 in Fig. 3 are corresponding to each other and the positions of the two lower waist-shape holes 33 in Fig. 3 are corresponding to each other. Therefore, the power transmission between the first and second slide blocks 13, 15 and the connection member 3 may be smoother.

The second column 18 is hinged to the connection member 3. More particularly, one end of the second column 18 is formed with two ears symmetrical to each other. The second column 18 may be hinged to the connection member 3 via the two ears. Thus, the second column 18 and the connection member 3 (as well as the first and second slide blocks 13, 15) may form a substantially closed space to avoid dust and impurity entering the substantially closed space, thus preventing affecting the rotation of the steering wheel. The universal joint 14 is located within the substantially closed space.

In some embodiments, the automatic adjustment apparatus of the steering wheel comprises a first guide cover 4 and a second guide cover 20 which are mounted onto the assembly frame 21, each of the first guide cover 4 and the second guide cover 20 has a substantially U-shape. A first guide groove is formed in a bottom of the first guide cover 4 for guiding the first slide block 13 and a second guide groove is formed in a bottom of the second guide cover 20 for guiding the second slide block 15.

In some embodiments, in order not to affect the sliding of the first and second slide blocks 13 15, a clearance may be left between the first guide groove and the first slide block 13 as well as between the second guide groove and the second slide block 15, so that the adjustment of the steering wheel is more accurate and smoother.

Meanwhile, when a big load is acted on the steering wheel, the first and second guide grooves may limit the first and second slide blocks 13, 15 and bear the pressure, so that the steering wheel may not deform under the big load, thus improving the deformation resistance of the steering wheel effectively.

In an embodiment of the present invention, the first guide cover 4 and the second guide cover 20 may be mounted to the assembly frame 21 by various means such as welding, rivet and bolt. As shown in Fig. 1, the first and second guide covers 4, 20 are connected to the assembly frame 21 by bolts 5.

In some embodiments, the first guide cover 4 and second guide cover 20 are connected to the assembly frame 21 with the openings of the first guide cover 4 and second guide cover 20 facing each other. The dimensions of the first guide cover 4 and second guide cover 20 may be designed properly to form an entire structure after connecting the first guide cover 4 and second guide cover 20. As a result, the entire structure may have a better dust-proofing effect and be more artistic.

For achieving better dust-proofing effect, one end of the second column 18 may be hinged to the connection member 3 and the other end thereof is disposed within the via hole of the assembly frame 21. As a result, the spline joint between the first column 11 and third column 19 may be sealed to avoid entering of the dust and impurity and prevent the relative sliding between the first column 11 and third column 19 from affecting. In order to prevent the first and second slide blocks 13, 15 from disengaging from the first and second screws 12, 17, one end of the first screw 12 is connected to the first step motor 8 and the other end thereof has a limit part 2, and one end of the second screw 17 is connected to the second step motor 24 and the other end thereof also has a limit part 2. The limit part 2 may be a limit ring or a limit pin.

In some embodiments, in order to conveniently mount the automatic adjustment apparatus to a vehicle, the assembly frame 21 has a mounting boss 6.

In some embodiment, for conveniently mounting a steering shaft lock (non shown), the third column 19 has a spline 9 and the assembly frame 21 has a locking hole, a locking tongue 7 of the steering shaft lock may be locked via the locking hole on the assembly frame 21 and the spline 9, thus realizing the locking of the steering shaft. Meanwhile, since the spline 9 is disposed in the via hole of the assembly frame 21, the anti-theft effect may be improved.

As shown in Fig. 4 and Fig. 5, according to another embodiment of the present invention, the automatic adjustment apparatus further comprises a limit bolt 22. The assembly frame 21 has a limit hole and the second column 18 has a waist-shape limit hole 23. The limit bolt 22 may be extended through and relatively slide along the waist-shape spacing hole 23, so as to avoid the steering wheel sliding to cause the disconnecting of the first column 11 and the third column 19, thus improving the safety of the automatic adjustment apparatus.

When the second column 18 moves by the driving of the connection member 3, the waist-shape limit hole 23 moves accordingly. So that the limit bolt 22 slides relative to the waist- shape spacing hole 23.

The length of the waist- shape limit hole 23 may be determined according to the extending and retracting stroke of the steering wheel. For example, the length may be slightly greater than the extending and retracting stroke of the steering wheel.

The limit hole may be formed in the assembly frame 21. For example, the limit hole may be formed at an end of the assembly frame 21 at which the locking hole is formed or at another end to which the locking hole is opposed.

The limit bolt 22 and the limit part of the screws may be used to prevented the first column 11 and the third column 19 from disconnecting from each other, thus avoiding hurting the driver when the steering wheel is being extended and retracting, and improving the safety of the automatic adjustment apparatus effectively.

In order to realize the automatic adjustment for the steering wheel, the first step motor 8 and the second step motor 24 are connected to the control devices such as ECU of the vehicle. The operation of the automatic adjustment apparatus according to embodiments will be described with reference to Fig. 1 and 2.

Only extending and retracting of the front column 1 : the ECU may send two pulse signals having a same frequency and representing a same direction to the first step motor 8 and the second step motor 24 respectively. The first step motor 8 and second step motor 24 may respectively drive the first screw 12 and the second screw 17 to rotate at a same rotating speed in the same direction. Accordingly, the first screw 12 and the second screw 17 may respectively drive the first slide block 13 and second slide block 15 to slide at a same speed in the same direction, thus driving the connection member 3 to extend (for example the first and second slide blocks 13, 15 moves upwardly in Fig. 2) and retract (for example the first and second slide blocks 13, 15 moves downwardly in Fig. 2), so that the extending and retracting of the front column 1( the steering wheel) is achieved.

Only tilting of the front column 1: the ECU may send two pulse signals have a same frequency and representing two opposite directions to the first step motor 8 and second step motor 24 respectively. The first step motor 8 and second step motor 24 may respectively drive the first screw 12 and the second screw 17 to rotate at a same rotating speed in the two opposite directions, and the first screw 12 and second screw 17 may respectively drive the first slide block 13 and second slide block 15 to slide at a same speed in two opposite directions, thus driving the connection member 3 to tilt (swing) towards the one slide block which is sliding downward in Fig.2, thus achieving the tilting of the front column 1.

Simultaneously tilting and extending and retracting of the front column 1 : the ECU may send two pulse signals with two different frequencies and representing a same direction (for example the frequency of one pulse signal is f while the frequency of the other is 2f) to the first step motor 8 and the second step motor 24 respectively. The first step motor 8 and second step motor 24 may rotate in a same direction and the rotating speed of one of the first step motor 8 and second step motor 24 is twice as large as that of the other one. When the first step motor 8 and second step motor 24 drive the first screw 12 and second screw 17 so as to drive the first and second slide blocks 13, 15, and thereby the connection member 3, because one slide block slides at a speed of V and the other one slides at a speed of 2V in the same direction. If both first and second slide blocks 13, 15 slide forwardly (upwardly in Fig. 2), the connection member 3 may drive the front column 1 to tilt towards the one slide block sliding moving at the speed of V and extend; if both first and second slide blocks 13, 15 slide backwardly (downwardly in Fig. 2), the connection member 3 may drive the front column 1 to retract and, at the same time, to tilt toward one slide block moving at a speed of 2V. Therefore, the titling and extending and retracting of the first column 1 are simultaneously realized.

With the automatic adjustment apparatus according to embodiments of the present invention, the first and second screws and the first and second guide blocks are driven via the first and second step motors respectively, thus achieving the extending and retracting and/or tilting (swing) of the connection member to adjust the steering wheel conveniently. The steering wheel of a vehicle may be adjusted by only control two step motors, so that the structure of the automatic adjustment apparatus and the control thereof are simple and ease to realize.

Moreover, the screw and the slide block may be interlocked by trapezoidal threads, and the limit part on the screw may limit the extending and retracting and/or tilting of the front column and the steering wheel. In addition, the limitation may be enhanced by the bolt provided on the assembly frame and second column. Therefore, the safety of the automatic adjustment apparatus of the present invention is ensured to improve the personal safety of the driver.

In addition, the guide covers is disposed on the assembly frame, thus improving the dust-proofing effect of the apparatus and prolonging service life of the apparatus, and the automatic adjustment apparatus is more artistic and natty. Because of the guide covers, when the steering wheel suffers a big load, the guide grooves may limit the slide block and bear the pressure, so that the steering wheel may not deform under the big load. Therefore, the deformation resistance of the steering wheel may be improved effectively.

Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that changes, alternatives, and modifications can be made in the embodiments without departing from spirit and principles of the disclosure. Such changes, alternatives, and modifications all fall into the scope of the claims and their equivalents.