JPH1143054A - Telescopic steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a smooth telescopic action in regard to a telescopic steering device adapting a clamp for holding a moving mechanism onto a stationary bracket. SOLUTION: In this telescopic steering device provided with a moving mechanism moving a telescopic tube together with an upper main shaft in the axial direction with respect to a lower tube and a lower main shaft, and with a clamp to be fixed to the lower tube in order to hold the moving mechanism, a groove part 47 and abutting parts 48 are provided for a facing surface 46 faced to the lower tube of the clamp 7. The groove part 47 is formed at the center portion of the abutting parts 46, and the abutting parts 48 are disposed apart while the groove part 47 is being held.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telescopic steering device, and more particularly to a telescopic steering device using a clamp for holding a moving mechanism on a fixed bracket.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Utility Model Laid-Open No. 3-47874.
As disclosed in Japanese Patent Application Laid-Open Publication No. H11-260, the steering shaft has a double structure and is relatively movable in the axial direction, so that the position of the steering wheel (the length in the axial direction) can be adjusted according to the physique and preference of the driver. Telescopic steering devices for adjusting the distance) are known.

[0003] In general, a telescopic steering device is provided with a fixed bracket that supports a fixed shaft.
The movable bracket, which supports the movable shaft, can be slid forward and backward. Then, the movable bracket is slid by moving the movable bracket in the axial direction by the moving mechanism, whereby the steering wheel attached to the movable shaft is moved forward and backward with respect to the driver.

The moving mechanism includes a motor, a screw shaft,
And a slider member, and the fixed bracket is provided with a motor and a screw shaft configured to be rotated by the motor. The movable bracket is provided with a slider member provided with a nut screwed into the screw shaft. Therefore, when the motor is driven and the screw shaft rotates, the nut screwed to the screw shaft is urged to move in the axial direction, whereby the movable bracket moves in the axial direction relative to the movable bracket, and performs a telescopic operation. It had been.

[0005] As described above, the screw shaft must be rotatably attached to the fixed bracket. Therefore, conventionally, a clamp is provided on a fixed bracket, and a screw shaft is supported by the clamp. This clamp consists of a pair of clamp halves, and after positioning the pair of clamp halves so as to sandwich the fixing bracket,
It was configured to be fixed to the fixing bracket using bolts or the like.

[0006]

The above-mentioned fixed bracket and movable bracket are both cylindrical. However, in order to smoothly slide the movable bracket with respect to the fixed bracket, the fixed bracket and the movable bracket must be fixed. It must be manufactured with high precision to have high cylindricity.

However, it is very difficult to manufacture the fixed bracket and the movable bracket with high accuracy due to the effects of thermal deformation due to welding performed during the manufacturing process, so that a manufacturing error necessarily occurs. . Therefore, fine irregularities are inevitably generated on the surface of the fixing bracket. The pair of clamp halves constituting the clamp have an opposing surface formed on an inner side surface facing the fixed bracket. The facing surface is configured to have a diameter substantially the same as the diameter of the fixing bracket. The entire surface of the facing surface is brought into contact with the surface of the fixing bracket, and is fixed using bolts or the like. Was. Therefore, when the convex portion exists on the surface of the fixing bracket as described above, only the portion where the convex portion is formed contacts the opposing surface of the clamp (that is, it contacts only one point), and the other portions Will be in a floating state.

As described above, when the clamp is not properly fixed to the fixing bracket, rattling occurs in the clamp, and accompanying this, a displacement occurs in the screw shaft supported by the clamp. Therefore, when the movable bracket is moved with respect to the fixed bracket, a smooth moving operation may not be performed, and a good telescopic operation may not be performed. In addition, vibration may occur during the telescopic operation, and this may become noise and propagate into the vehicle interior.

The present invention has been made in view of the above points, and provides a telescopic steering device that enables smooth telescopic operation by configuring a clamp so as to abut against a fixed bracket only at both side positions thereof. The purpose is to:

[0010]

According to the present invention, there is provided a fixing bracket fixed to a vehicle body,
A fixed shaft rotatably supported by the fixed bracket, a movable bracket slidably connected to the fixed bracket in an axial direction, and a movable bracket connected to the fixed shaft movably in an axial direction and integrally rotatable. A movable shaft rotatably supported by a bracket, a moving mechanism for moving the movable bracket together with the movable shaft in the axial direction with respect to the fixed bracket and the fixed shaft, and a mechanism for holding the moving mechanism on the fixed bracket. In a telescopic steering device having a clamp fixed to the fixed bracket, a groove portion and a pair of contact portions abutting on the fixed bracket are provided on an opposing surface of the clamp facing the fixed bracket, and the groove portion is provided. Formed at a substantially central portion of the facing surface, and
The abutting portion is spaced apart from the groove portion.

The above technical means operates as follows. The moving mechanism moves the movable bracket in the axial direction with respect to the fixed bracket. A groove and a pair of abutting portions are formed on a surface of the clamp facing the fixing bracket. The groove is formed substantially at the center of the opposing surface, and the pair of abutting portions are disposed apart from each other with the groove interposed therebetween. Therefore, in the fixed state where the clamp is fixed to the fixed bracket, only the pair of contact portions comes into contact with the fixed bracket.

In this manner, the clamp has a configuration in which the abutting portion abuts on the fixed bracket at two separate positions, and the intermediate portion does not abut on the fixed bracket due to the groove.
For this reason, even if the fixing bracket has irregularities,
The clamp always comes in contact with at least two points separated from each other, and it is possible to prevent a contact state in which the clamp comes into contact with only one point as in the related art.

Accordingly, the clamp is fixed to the fixing bracket in a stable state, and it is possible to prevent rattling and vibration. Therefore, a telescopic operation that is smooth and free of noise can be realized.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show the entire configuration of a telescopic steering apparatus according to one embodiment of the present invention. FIG. 1 is a front view of the telescopic steering device, and FIG. 2 is a plan view of the telescopic steering device.

As shown in each of the drawings, the telescopic steering apparatus according to the present embodiment includes a steering column 1 and a lower tube 3, which are generally fixed brackets.
Lower main shaft 27 serving as a fixed shaft, telescopic tube 2 and upper tube 4 serving as a movable bracket, upper main shaft 2 serving as a movable shaft
5 and a moving mechanism 23.

The steering column 1 has a cylindrical lower tube 3, on which a lower main shaft 3 is provided. The lower main shaft 27 is rotatably supported in the lower tube 3. The lower tube 3 is fixed to the vehicle body via a bracket 28, and thus the lower main shaft 27 is also fixed to the vehicle body. Further, an end of the lower main shaft 27 in the X1 direction in the drawing is connected to a steering gear box (not shown) for steering the tire.

On the other hand, a bush 21 is
(Shown in FIG. 6), the cylindrical telescopic tube 2 is axially moved relative to the lower tube 3 (in the figure, arrow X
1, X2 direction). The telescopic tube 2 has a moving mechanism 23 described in detail later.
Are arranged and the upper tube 4 is attached.

The upper tube 4 has a bifurcated arm portion 32 formed at the end in the direction X1 in the figure. Both arms 32 are rotatably supported by the telescopic tube 2 by a support shaft 33. ing. The upper tube 4 is provided with a tilt motor 5 (FIG. 1).
), A screw is formed on the drive shaft 34 of the tilt motor 5.

Further, a rack 35 is rotatably disposed at a position facing the drive shaft 34 of the telescopic tube 2, and the rack 35 is screwed with the drive shaft 34 having a screw shape. Therefore, when the tilt motor 5 is driven, the distance between the telescopic tube 2 and the upper tube 4 at the position where the tilt motor 5 is disposed expands and contracts, whereby the upper tube 4 moves about the support shaft 33 with respect to the telescopic tube 2. It rotates in the directions indicated by arrows D1 and D2 in FIG. Thus, the steering can be tilted.

The upper tube 4 is provided with a cylindrical tilt bracket 26, in which an upper main shaft 25 is rotatably mounted. The steering is attached to the end of the upper main shaft 25 in the X2 direction in the drawing. Further, the upper main shaft 25 is connected to the lower main shaft 27 via a joint (not shown) and a middle shaft.
When the upper main shaft 25 is rotated by operating the steering wheel, the rotational force is transmitted to the lower main shaft 27 via the joint and the middle shaft. Therefore, by rotating the steering wheel, the lower main shaft 27 also rotates.

The joint provided between the upper main shaft 25 and the lower main shaft 27 is driven by the tilt motor 5 as described above, and the upper tube 4 is moved relative to the telescopic tube 2 in the directions of arrows A1 and A2. The function of maintaining the transmission of the rotational force between the upper main shaft 25 and the lower main shaft 27 even if the rocking operation is performed.

The middle shaft provided between the upper main shaft 25 and the lower main shaft 27 has a configuration in which the upper main shaft 25 and the lower main shaft 27 are connected by, for example, spline fitting. Accordingly, the telescopic tube 2, the upper tube 4, and the tilt bracket 26 correspond to the arrow X in the drawing with respect to the lower tube 3I fixed to the vehicle body as described above.
When it moves in the X1 and X2 directions, the middle shaft expands and contracts accordingly, so that even if the telescopic tube 2 moves relative to the lower tube 3I, the upper main shaft 25 can move in the axial direction to the lower main shaft 27,
Further, it is configured to maintain a state of being integrally connected.

Next, the moving mechanism 23 will be described with reference to FIGS. 1 and 2 and FIGS. The moving mechanism 23 moves the telescopic tube 2 serving as a movable bracket, the upper tube 4 together with an upper main shaft 25 serving as a movable shaft, the steering column 1, the lower tube 3 serving as a fixed bracket, and the lower main shaft 27 serving as a fixed shaft. It has a function of moving in the axial direction (the directions of arrows X1 and X2).

The moving mechanism 23 includes a telescopic motor 6, a clamp 7, a cable 8, a telescopic screw 9, a telescopic slider 18, a wedge lock 18,
And a bearing mechanism 36 and the like. As the telescopic motor 6, an ultrasonic motor which is a direct drive motor is used. In this embodiment, the telescopic motor 6
Are fixed to the lower tube 3 with screws. The telescopic motor 6, which is an ultrasonic motor, has a configuration in which an output shaft is rotated by a frictional force acting between a vibrating body made of a piezoelectric element and ultrasonically vibrating and a moving body connected to the output shaft 29. ing. Therefore, when a thrust force (force in the direction of arrow X1 in the figure) acts on the input shaft 29, the frictional state between the vibrating body and the moving body changes, and even if the vibrating body vibrates, the moving body (ie, , The output shaft 29) may not rotate as described above.

However, since the ultrasonic motor generates a high torque at a low rotation speed as compared with a motor having another configuration (hereinafter, referred to as a conventional motor), by using this ultrasonic motor as the telescopic motor 6, the conventional motor can be used. It is possible to reduce the size and the number of parts of the entire telescopic steering device without requiring the required speed reduction mechanism.

The telescopic motor 6 having the above structure includes:
The cable 8 is connected. The cable 8 is formed of a flexible metal material such as spring steel, for example.
Therefore, when a force is applied in the torsion direction, a slight torsion is generated. At least an end of the cable 8 in the direction of arrow X1 (hereinafter, this portion is referred to as an engaging portion 8a) has a rectangular cross section.
A square hole 30 corresponding to the shape of the engaging portion 8a is formed in the output shaft 29 of the telescopic motor 6 with which the a is engaged.
The cable 8 is connected to the telescopic motor 6 by inserting and engaging the engaging portion 8a into the square hole 30. The cable 8 according to the present embodiment
Has a rectangular cross section as a whole to facilitate molding.

When the engaging portion 8a is engaged with the square hole 30 as described above, a small gap is formed between the engaging portion 8a and the square hole 30. Hole 3
The depth 0 is formed to be sufficiently longer than the engaging portion 8a. That is, the engaging portion 8a of the caple 8 is configured to be able to move in the axial direction of the output shaft 29 (directions of arrows X1 and X2) while maintaining the engaging state with the output shaft 29 of the telescopic motor 6.

Therefore, even if the cable 8 moves toward the output shaft 29 of the telescopic motor 6 (that is, X1) due to an assembly error of each component constituting the telescopic steering device and a thermal expansion due to a temperature change or the like. Direction), the engaging portion 8a of the cable 8 moves in the X1 and X2 directions in the output shaft 29, whereby the movement of the cable 8 due to the assembly error and the temperature change is absorbed.

Therefore, no thrust force is generated in the telescopic motor 6, and the telescopic motor 6 can always rotate stably. Thus, even when an ultrasonic motor that is a direct motor is used as the telescopic motor 6, a stable telescopic operation can always be realized. Further, a telescopic screw 9 is provided at an end 8b of the above-described caple 8 on the side of the arrow X2 in the figure.
Is arranged. This telescopic screw 9 also has a square hole 31
(Appearing in FIGS. 3 and 4) are formed, and the end 8b is configured to be axially displaceable within the square hole 31. Therefore, the thrust force described above can be absorbed even at the engagement position between the end 8b and the square hole 31.

The telescopic screw 9 is mounted on the clamp 7 by a bearing mechanism 36 (to be described in detail later). The telescopic screw 9 is supported by the flange 9a, the clamp 7 and the bearing mechanism 36, and the above-described square hole 31, a screw portion 9 c extending in the direction of the arrow X <b> 2 and formed with a screw, and an extension shaft portion 9.
The screw part 9d which is formed in a part of b and to which a lock nut 16 to be described later is screwed is integrally formed.

A clamp 7 for bearing a telescopic screw 9 is fixed to the lower tube 3. Therefore, the telescopic screw 9 is also arranged on the lower tube 3. Also, the screw portion 9 of the telescopic screw 9
c extends long in the direction of arrow X2, and specifically, extends to a position facing the telescopic tube 2 slidably inserted into the lower tube 3.

A telescopic slider 17 is fixed to the telescopic tube 2, and a nut 37 is provided inside the telescopic slider 17 (shown in FIG. 4). The screw portion 9 c of the telescopic screw 9 is screwed with a nut 37 provided inside the telescopic slider 17. Next, the bearing mechanism 36 for bearing the telescopic screw 9 on the clamp 7 will be described.

The bearing mechanism 36 includes first and second bearings 10 and 15, first to fourth bushes 11 to 14, and a lock nut 16. The first and second bearings 10, 15 are both thrust ball bearings. The first and fourth bushes 11 and 14 have a concave curved surface 38, and the second and third bushes 1 and
2, 13 have a convex curved surface 39 formed thereon. The curvature of the concave surface 38 is substantially equal to the curvature of the convex surface 39.

To assemble the bearing mechanism 36, first, the first bearing 1 is attached to the extension shaft 9 b of the telescopic screw 9.
Then, the first bush 11 and the second bush 12 are inserted. As described above, the flange portion 9a is formed on the telescopic screw 9, and the first bearing 10 inserted through the extension shaft portion 9b is connected to the flange portion 9a.
a. Therefore, the first bearing 10 and the first and second bushes 11 and 12 do not move to the screw portion 9c side.

As described above, when the first bearing 10, the first and second bushes 11, 12 are inserted through the extension shaft 9b, the extension shaft 9b is formed on the clamp 7. It is attached to the support shaft 22. Specifically, an insertion hole 40 is formed in the support shaft portion 22, and the extension shaft portion 9 b is inserted into the insertion hole 40 to thereby connect the extension shaft portion 9 b to the support shaft portion 2.
Attach to 2. At this time, the diameter of the insertion hole 40 is formed slightly larger than the diameter of the extension shaft portion 9b, and therefore, the extension shaft portion 9b is in a loosely fitted state with the insertion hole 40.

Subsequently, a third bush 13, a fourth bush 14, and a second bearing 15 are inserted in this order into a portion of the extension shaft 9b extending from the support shaft 22 in the direction of arrow X1. Finally, the lock nut 16 is inserted and screwed into the screw portion 9d formed on the telescopic screw 9. As a result, the first and second bearings 10, 1
5. The first to fourth bushings 11 to 14 are configured to be fastened between the lock nut 16 and the flange 9 a formed on the telescopic screw 9.

However, as described above, the first bearing 10 is disposed at a position facing the flange 9a, and the second bearing 15 is disposed at a position facing the lock nut 16, and Since the bearings 10 and 15 are thrust bearings, the rotation of the telescopic screw 9 is ensured. Here, the first to fourth bushes 11
The following description focuses on the shapes of Nos. To 14. As described above, the first and fourth bushes 11 and 14 are formed with the concave curved surface 38, and the second and third bushes 12 and 1 are formed.
3 is a convex curved surface 3 having substantially the same curvature as the concave curved surface 38.
9 are formed. Further, the extension shaft portion 9b of the telescopic screw 9 is in a loosely fitted state in the insertion hole 40.

Therefore, the displacement of the concave curved surface 38 on the convex curved surface 39 allows the telescopic screw 9 to swing with respect to the support portion 22 as shown by arrows E1 and E2 in FIGS. . That is, by allowing the telescopic screw 9 to be supported by the clamp 7 using the bearing mechanism 36,
The telescopic screw 9 is configured to be swingably displaceable about the support portion 22 of the clamp 7.

Next, the structure of the clamp 7 will be described with reference to FIG. 3 and FIGS. FIG. 6 shows A in FIG.
7 is a cross-sectional view taken along the line BB in FIG. 1, and FIG. 8 is a cross-sectional view as viewed from the direction of arrow F in FIG. As shown in FIG. 6, the clamp 7 includes a first clamp half 7A and a second clamp half 7A.
B. The first and second clamp halves 7A and 7B are opposed to each other with the lower tube 3 interposed therebetween, and are fixed to the lower tube 3 by being fastened with bolts 41 and 42 (shown in FIG. 7). Have been.

Although the telescopic tube 2 is slidably inserted into the lower tube 3 as described above, the telescopic tube 2 is inserted into the lower tube 3.
A bush 21 is provided between the lower tube 3 and the telescopic tube 2 so that no rattling occurs. Further, a wedge lock 18 is provided on the first clamp half 7A in order to always keep the telescopic tube 2 in sliding contact with the lower tube 3 via the bush 21.

The wedge lock 18 is configured to be movable in the direction indicated by arrows Y 1 and Y 2 in FIG. 6 in the clamp 7, and is telescopic through an opening 43 formed in the lower tube 3 and the bush 21. An inclined surface 44 is formed at a portion facing the tube 2. Further, a spring 19 is provided inside the clamp 7,
One end of the spring 19 comes into contact with a bolt 20 screwed to the clamp 7, and the other end is connected to a wedge lock 18.
Is in contact with Therefore, the wedge lock 18 is always urged in the direction of the arrow Y1 by the spring force of the spring 19. Therefore, the inclined surface 44 of the wedge lock 18 always presses and biases the telescopic tube 2 toward the lower tube 3, so that a stable sliding operation of the telescopic tube 2 can be ensured.

In order to always slide the telescopic tube 2 in a stable state as described above, it is necessary to stabilize the force of the wedge lock 18 pressing the telescopic tube 2 toward the lower tube 3. For this purpose, the spring 19 is
It is necessary to make the spring force acting on 8 constant. However, the telescopic tube 2 slides with respect to the lower tube 3 and wears over time, and the sliding contact portion (including the bush 21) between the telescopic tube 2 and the wedge lock 18 wears over time. Occurs.

In this embodiment, one end of the spring 19 is connected to the bolt 2 so that the spring 19 can keep the spring force acting on the wedge lock 18 constant even if such wear occurs.
0 to adjust the degree of screwing of the bolt 20. Thus, even when wear occurs, it is possible to adjust the spring force acting on the wedge lock 18 using the bolt 20 to be a predetermined value.

When attention is paid to the relationship between the spring force generated by the spring 19 and the spring length, when a predetermined spring force is to be generated, the spring constant can be reduced if the spring length is long. Conversely, when the spring length is short, the spring constant needs to be set high. On the other hand, in the above adjustment work, if the spring length of the spring 19 is short, the spring force changes greatly due to a small displacement of the bolt 20, and adjustment is difficult. On the other hand, when the spring length of the spring 19 is long, the amount of change in the spring force due to the displacement of the bolt 20 is small, so that the adjustment is easy. Further, if the spring length of the spring 19 is simply increased, the size of the clamp 7 is increased. From this point, it is desirable that the spring length of the spring 19 is shorter.

Therefore, in this embodiment, the wedge lock 18
Is provided with an insertion hole 45 into which the spring 19 is inserted.
While setting the spring length of the spring 19 long,
Has been reduced in size. Thus, the adjustment of the spring force by the bolt 20 can be easily performed, and the size of the clamp 7 can be reduced. By the way, as described above, the clamp 7 includes the telescopic screw 9 and the bearing mechanism 3.
6 must be fixed to the lower tube 3 reliably.

For this purpose, it is necessary to manufacture the lower tube 3 and the clamp 7 with high precision. However, since the lower tube 3 has a cylindrical shape, it is very difficult to manufacture it with high cylindricity with high accuracy due to the influence of thermal deformation due to welding performed at the time of manufacturing. Inevitably, fine irregularities are generated on the surface of.

Therefore, if the entire surface of the surface of the clamp 7 facing the lower tube 3 (hereinafter referred to as the facing surface 46) is in contact with the surface of the lower tube 3, only the portion where the convex portion is formed is formed by the clamp 7. It may come into contact with the facing surface 46 (that is, it will come into contact at only one point), and the other parts will be in a floating state, which may cause rattling or noise.

However, in the present embodiment, FIG.
As shown in the first clamp half 7A only), a facing surface 46 of the clamp 7 facing the lower tube 3 is shown.
A groove 47 and a contact portion 48 are formed in the groove. The groove portion 47 is a portion that is depressed with respect to the contact portion 48, and the amount of the depression is set to be at least larger than the height of the convex portion generated on the surface of the lower tube 3. The groove 47 is formed substantially at the center of the facing surface 46.

The contact portion 47 is a portion that contacts the surface of the lower tube 3 when the clamp 7 is fixed to the lower tube 3. The contact portion 47 is provided in the groove 4
7 are spaced from each other. When the clamp 7 is configured as described above, the clamp 7 (clamp halves 7A, 7A)
In a fixed state where B) is fixed to the lower tube 3, only the pair of contact portions 47 separated in the axial direction (the directions of the arrows X <b> 1 and X <b> 2) comes into contact with the lower tube 3. That is, the contact portions 47 of the clamps 7 (clamp halves 7A and 7B) are in contact with the lower tube 3 at two positions separated in the directions of arrows X1 and X2, and the intermediate portion is in contact with the lower tube 3 due to the presence of the groove 47. It will not be in contact.

As a result, even if the surface of the lower tube 3 has irregularities, the lower tube 3 and the clamp 7 always come into contact with each other at two separated points (that is, the contact portions 47). Further, it is possible to prevent the occurrence of the contact state in which the contact occurs at only one point. As a result, the clamp 7 is fixed to the lower tube 3 in a stable state, and it is possible to prevent rattling and vibration. Therefore, the clamp 7
With the above configuration, a telescopic operation that is smooth and free of noise can be realized.

Next, the operation of the telescopic steering apparatus having the above configuration will be described. To start the telescopic operation, first, the telescopic motor 6 is started. Thereby, the output shaft 29 of the telescopic motor 6 rotates, and this rotational force is transmitted to the telescopic screw 9 via the cable 8. Then, the telescopic screw 9
Rotates, and accordingly, the screw portion 9 c rotates in the nut 37 of the telescopic slider 17. As mentioned above,
Since the screw portion 9c is screwed with the nut 37, when the telescopic screw 9 rotates, the telescopic tube 2 moves with respect to the lower tube 3 by an arrow X in the figure.
1 and X2, the upper main shaft 25 to which the steering wheel is attached is also moved by the arrow X.
Move in the 1, X2 directions. As a result, the steering wheel moves in a direction approaching or away from the driver, and can be positioned at a steering position corresponding to the physique and preference of the driver.

In this embodiment, the telescopic motor 6
An ultrasonic motor which is a direct drive motor is used. By using an ultrasonic motor as the telescopic motor 6, low rotation and high torque can be realized without using a speed reduction mechanism as described above, and therefore, the size, cost, and noise of the telescopic steering device can be reduced. Can be.

However, when an ultrasonic motor is used as the telescopic motor 6, depending on the magnitude of the driving torque required to move the telescopic tube 2 or the like, there may be a case where quick start cannot be performed. about this,
This will be described with reference to FIG. FIG. 5 shows the relationship between the rotation speed of the telescopic motor 6 which is an ultrasonic motor and the motor torque. As shown in the figure, when the output shaft 29 is rotating (that is, when the motor is driven), the ultrasonic motor has a characteristic that the motor torque increases as the rotation speed decreases, and Is near zero, the maximum torque T
Output _MAX . On the other hand, the torque at the time of starting the stopped ultrasonic motor (starting torque T _S ) is lower than the above-described maximum torque T _MAX .

Therefore, when an ultrasonic motor is used as the telescopic motor 6, for example, the driving torque T _D required to move the telescopic tube 2 or the like (this is equivalent to the torque required to rotate the telescopic screw 9) is obtained. Greater than the starting torque T _S and the maximum torque T
If it is smaller than _MAX (T _S <T _D <T _MAX ),
Drive torque T _D is despite the maximum torque T _MAX is less than if the telescopic operation is not performed is generated.

In order to avoid this, the output shaft 29 of the telescopic motor 6 may be rotated immediately after the start of the telescopic motor 6 because the output shaft 29 may be a small amount.
If the output shaft 29 rotates by a small amount, the telescopic motor 6 generates a larger torque than the characteristic shown in FIG. 5, so that the telescopic screw 9 can be rotated, and the telescopic operation can be performed.

Therefore, in the present embodiment, as described above,
The pull 8 is formed of a flexible metal material such as spring steel.
Causes slight torsion when force is applied in the torsion direction.
It was configured to live. Specifically, the telescopic motor 6
(Ultrasonic motor) starting torque T _SLower torque sign
In addition, the caple 8 is configured to be twisted.
With the above configuration, the start-up of the telescopic motor 6
Later, the telescoping due to the twisting of the cable 8
Even if the output shaft 29 of the comotor 6 rotates,
The state in which the queue 9 does not rotate can be realized. However
The rotation of the output shaft 29 causes the cable 8 to be twisted.
Therefore, the rotation is minute.

Here, the telescopic motor 6 shown in FIG.
The characteristics of the (ultrasonic motor) will be noted again. This implementation
In the example configuration, the caple 8 is the starting trigger of the telescopic motor 6.
Luc T _SIt is configured to be twisted by applying lower torque
Therefore, the drive required to rotate the telescopic screw 9
Torque T_DIs the starting torque T_SEven larger
The telescopic motor 6 rotates by twisting the telescopic motor 8.

The rotation of the telescopic motor 6 occurring at this time
Is caused only by the twisting of the caple 8
Therefore, the rotation speed is very small. On the other hand,
As described above, the telescopic motor 6 (ultrasonic motor)
Once rotation starts, the motor torque decreases as the rotation speed decreases.
Has an increasing characteristic. Therefore, the telescopic motor
6 is that the caple 8 twists and rotates slightly at startup.
From the maximum torque T_MAXGenerates torque close to. this
The starting torque T _SIs the driving torque T_DSmaller
Also, the telescopic motor 6 has almost the maximum torque immediately after startup.
T_MAXIs generated, and the driving torque T_DIs activated
Luc T_SLarger and maximum torque T_MAXSmaller place
Even if the telescopic operation is reliable.
Can be possible.

When the telescopic motor 6 is started, the telescopic tube 2 starts moving in the directions of arrows X1 and X2 in the figure with respect to the lower tube 3, but slides the telescopic tube 2 smoothly with respect to the lower tube 3. In order to move the tube, it is necessary to manufacture the telescopic tube 2 and the lower tube 3 with high accuracy so as to have a high cylindricity.

However, as described above, it is difficult to manufacture the telescopic tube 2 and the lower tube 3 with high accuracy so as to have a high cylindricity. In order to smoothly slide the telescopic tube 2 with respect to the lower tube 3, the components such as the telescopic motor 6, the telescopic screw 9, and the nut 37 need to be accurately attached. Also inevitably includes manufacturing errors, and mounting errors also occur when mounting each component. These may cause "torsion" between the telescopic screw 9 and the nut 3 when the telescopic tube 2 slides.

In this embodiment, however, the telescopic screw 9 is swingably supported by a bearing mechanism 36 provided on the clamp 7. That is, as described with reference to FIGS. 3 and 4, the first and fourth bushes 11, 1
4 has a concave curved surface 38, and the second and third bushes 12, 13 have a convex curved surface 39 having a curvature substantially equal to that of the concave curved surface 38. Therefore, the convex surface 39
Above, the concave curved surface 38 is configured to be displaceable,
The first and fourth bushings 12 and 13
Are configured to be displaceable.
Further, the extension shaft portion 9b of the telescopic screw 9 is in a loosely fitted state in the insertion hole 40.

Therefore, the displacement of the concave curved surface 38 on the convex curved surface 39 allows the telescopic screw 9 to swing with respect to the support portion 22 as shown by arrows E1 and E2 in FIGS. . That is, by allowing the telescopic screw 9 to be supported by the clamp 7 using the bearing mechanism 36,
The telescopic screw 9 is configured to be swingably displaceable about the support portion 22 of the clamp 7.

As described above, the telescopic screw 9 is configured to be able to swing and displace around the support portion 22 of the clamp 7 by the bearing mechanism 36, so that the telescopic screw 2 and the lower tube are connected to each other due to manufacturing errors and assembly errors. Even if there is an axis deviation between the tube 3 and the tube 3, the axis deviation is absorbed by the oscillating displacement of the telescopic screw 9.
Therefore, it is possible to prevent the occurrence of “twisting” at the screwing portion between the telescopic screw 9 and the nut 37 (the telescopic slider 17), and to realize a smooth telescopic operation.

In addition, a machine tool and an assembly machine with high machining accuracy are not required, so that cost increase can be suppressed, and "pricking" itself can be prevented, so that the reliability of the telescopic steering device does not deteriorate with time and the reliability can be improved. Can be improved.

[0065]

As described above, according to the present invention, the clamp is fixed to the fixing bracket in a stable state, and the occurrence of rattling and vibration can be prevented. Therefore, a telescopic operation that is smooth and free of noise can be realized.

[Brief description of the drawings]

FIG. 1 is a front view of a telescopic steering device according to an embodiment of the present invention.

FIG. 2 is a plan view of a telescopic steering device according to one embodiment of the present invention.

FIG. 3 is an exploded perspective view of a moving mechanism provided in the telescopic steering device according to one embodiment of the present invention.

FIG. 4 is a partial cutaway view of a moving mechanism provided in the telescopic steering device according to one embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between the rotational speed of the ultrasonic motor and the motor torque.

FIG. 6 is a sectional view taken along line AA in FIG.

FIG. 7 is a sectional view taken along line BB in FIG. 1;

8 is a view of the clamp as viewed from the direction of arrow F in FIG. 7;

[Explanation of symbols]

 Reference Signs List 1 steering column 2 telescopic tube 3 lower tube 4 upper tube 5 tilt motor 6 telescopic motor 7 clamp 7A first clamp half 7B second clamp half 8 cable 9 telescopic screw 9a flange 9b extension shaft 9c screw 9d screw portion 10 first bearing 11 first bush 12 second bush 13 third bush 14 fourth bush 15 second bearing 17 telescos slider 18 wedge lock 19 spring 22 support portion 23 moving mechanism 25 upper main Shaft 26 Tilt bracket 27 Lower main shaft 28 Bracket 30, 31 Square hole 34 Drive shaft 38 Concave curved surface 39 Convex curved surface 44 Inclined surface 46 Opposing surface 47 Groove portion 48 Contact portion

Claims (1)

[Claims] 1. A fixed bracket fixed to a vehicle body, a fixed shaft rotatably supported by the fixed bracket, a movable bracket slidably connected to the fixed bracket in an axial direction, and the fixed shaft. A movable shaft rotatably supported by the movable bracket and connected to the movable bracket so as to be movable in the axial direction and integrally rotatable; and moving the movable bracket together with the movable shaft in the axial direction with respect to the fixed bracket and the fixed shaft. In a telescopic steering device having a moving mechanism and a clamp fixed to the fixed bracket for holding the moving mechanism on the fixed bracket, a groove portion and the fixed bracket are provided on an opposing surface of the clamp facing the fixed bracket. A pair of abutting portions that abut against each other, and Formed in the substantially central portion of the opposing surface, and telescopic steering apparatus, characterized in that the abutment is spaced arranged across the groove.