JPH05330434A - Driving device - Google Patents

Abstract

PURPOSE:To improve the screwing strength between a screw shaft and a nut member without increasing the pressing force of a pressing member. CONSTITUTION:A nut member 12 is energizing-deformed in the radial direction so as to be pressing-contracted towards the axis center by a slider 18 which is wedge-engaged with the nut member 12, and the load in the axial direction which acts on a screw shaft 9 is absorbed by the wedge engagement between the nut member 12 and the slider 18.

Description

Detailed Description of the Invention

[0001]

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for moving a movable member with respect to a fixed member by relative movement of a screw shaft and a nut member, and is used for a position adjusting mechanism of a steering device or a seat device. It

[0003]

2. Description of the Related Art Conventionally, as a drive device of this type, a drive device disclosed in JP-A-59-230861 is known. This has a screw shaft rotatably supported by a fixed member and linked to a drive mechanism, and a nut member supported by a movable member and screwed to the screw shaft. The nut member is rotated to move the nut member relative to the screw shaft, thereby moving the movable member with respect to the fixed member. A pressing member is arranged around the nut member, and the nut member directly receives the pressing force in the radial direction from the pressing member, so that the slit formed on the nut member strengthens the screw engagement with the screw shaft. Then, the nut member and the screw shaft were screwed into each other so as to be pressed and compressed toward the axial center so as to be compressed in the radial direction.

[0004]

However, in the above drive device, when an axial load acts on the screw shaft side, this load acts on the nut member so as to push the nut member outward in the axial direction. To do. At this time, since the radial pressing deformation of the nut member is carried out by directly receiving the radial pressing force from the pressing member, the load acting on the nut member is absorbed only by the pressing force of the pressing member. As a result, the nut member is restricted from being pushed and spread outward in the axial direction. For this reason, if the pressing force of the pressing member has an appropriate size for screwing the nut member and the screw shaft without rattling, the load exerted on the nut member by the pressing member cannot be absorbed completely, and it is easy to work together with the nut member. The nut member is pushed outwards, and as a result, the screw engagement between the nut member and the screw screw is weakened, and the nut member may be disengaged from the screw screw.

That is, the screwing strength between the nut member and the screw shaft is insufficient. When the pressing force of the pressing member is set to a value such that the load acting on the nut member is absorbed, the pressing force applied to the nut member from the pressing member also increases, and the nut member and the screw shaft are screwed more than necessary. As a result, there is a risk of malfunction.

Therefore, it is a technical object of the present invention to improve the screwing strength between the screw shaft and the nut member without increasing the pressing force of the pressing member.

[0007]

[Constitution of the invention]

[0008]

In order to solve the above technical problems, the technical means taken in the present invention is a pressing means for pressing and deforming the nut member in the radial direction so that the nut member is screwed with the screw shaft. It is configured to have a slider that is arranged around the nut member so as to be movable in the axial direction and that engages with the nut member by a wedge, and a biasing member that biases the slider in the axial direction.

[0009]

In the above technical means, an axial load acts on the screw shaft, and even if the nut member is pushed outward by the load due to this load, the load is applied to the wedge member between the slider and the nut member. The nut member is restrained from being pushed and spread outward in the axial direction. As a result, the screwing strength between the screw shaft and nut member is improved without increasing the pressing force of the pressing member.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, an upper bracket 3 is rotatably supported by a pin 4 on a breakaway bracket 2 fixed to a vehicle body 1. A lower main shaft 5 is rotatably supported on the breakaway bracket 2 and an upper main shaft 6 is rotatably supported on the upper bracket 3. The upper main shaft 6 is connected to the lower main shaft 5 via a universal joint (not shown) arranged coaxially with the pin 4, and a handle 7 is fixed to the tip thereof.

As shown in FIGS. 1 to 3, a plate 8 is fixed to the breakaway bracket 2. A screw shaft 9 having a screw portion 9a formed on the outer peripheral surface thereof is rotatably supported on the plate 8.
A link 10 is rotatably supported by a pin 11 on the upper bracket 3 and a nut member 12 (described later) screwed to the screw shaft 9 is rotatably supported on the link 10 by a bolt 36. There is.

As shown in FIGS. 3-6, nut member 12 comprises a first body portion 13 and a second body portion 14. A screw member 1 in which a female screw portion 16a to be screwed with an external screw portion 9a of the screw shaft 9 is formed on the inner surface of the housing 15 which constitutes the first main body portion 13.
6 is integrally provided by molding. One end of the screw member 16 projects outward in the axial direction from the housing 15, and a taper portion 16b is formed on the outer peripheral surface of the projecting portion. On the tapered portion 16b, axial slits 16c are formed in four cross-shaped portions. A slider 18 is provided in a housing 17 that constitutes the second body portion 14 so as to be movable in the axial direction.
On the inner peripheral surface of the slider 18, a taper portion 18a that can be engaged with the taper portion 16b of the screw member 16 is formed.
On the tapered portion 18a, axial slits 18b are formed in four cross-shaped portions. Further, the housing 17 is provided with a biasing member 20 that constantly biases the slider 18 in a direction in which the taper portion 18a of the slider 18 and the taper portion 16b of the screw member 16 are engaged with each other.

The first main body portion 13 and the second main body portion 14 having the above-described structure are tapered portions 18a of the slider 18.
After the taper portion 16b of the screw member 16 is arranged inside, the housing 15 and the housing 17 are fastened with the screw 22 via the plate 21 arranged on the second main body portion 14 side, It is assembled. At this time, the slider 18 and the biasing member 20 are pushed in axially so that the taper portion 18a of the slider 18 and the taper portion 16b of the screw member 16 are strongly engaged with each other via the plate 21 by fastening the screw 22. .. As a result, a radial pressing force acts on the taper portion 16b of the screw member 16 by the engagement of the taper portion 18a of the slider 18 and the taper portion 16b of the screw member 16, and the taper portion 16b of the screw member 16 slides. 16c, the nut member 12 and the screw screw 9 screwed into the nut member 12 are pressed and deformed toward the axial center so that the nut member 12 and the screw screw 9 screwed into the nut member 12 are radially compressed. 16a and the external thread portion 9a of the screw shaft 9 are fitted properly. As a result, smooth relative movement of the screw shaft 9 and nut member 12 described later can be obtained while the screw shaft 9 and nut member 12 are screwed together without play. Even if the internal thread portion 16a of the screw member 16 and the external thread portion 9a of the screw shaft 9 are worn due to aging, the slider 18 is urged by the urging member 20 to cause the taper portion 18a and the taper portion 16b of the screw member 16 to wear. Since they are urged in the engaging direction, the taper portion 16b is further urged and deformed by the amount of wear due to the urging force of the urging member 20, and the screw member 16
Female thread 16a and male thread 9a of screw screw 9
The mating with and is kept in a proper state.

When a load is applied to the screw shaft 9 in the axial direction and the load acts on the nut member 12 so as to push the screw member 16 outward in the shaft direction and radially, the load is applied to the slider 18. It is absorbed by the frictional force between the taper portion 18a and the taper portion 16b of the screw member 16, and the slider 18 does not move in the axial direction by this load. As a result, the screw member 16 is attached to the screw shaft 9
The slider 18 reliably restricts radial expansion due to the axial load applied to the screw 18, and the screwing between the screw shaft 9 and nut member 12 is not weakened. Further, since the load acting in the axial direction of the screw shaft 9 hardly acts on the biasing member 20, it is not necessary to increase the biasing force of the biasing member 20 so as to withstand the load acting in the axial direction of the screw shaft 9. Therefore, the screwing between the screw shaft 9 and the nut member 12 will not be unnecessarily strengthened by the biasing force of the biasing member 20.

The plate 21 arranged on the side of the second main body portion 14 is provided with a stopper body 33 for restricting the relative movement of the nut member 12 with respect to the screw shaft 9 by the rotation of the screw shaft 9, which will be described later. 1
A plate 34 is also arranged on the side of the main body portion 13, and a stopper body 35 for restricting relative movement of the nut member 12 with respect to the screw shaft 9 due to rotation of the screw shaft 9 described later is also provided on this plate 34.

As shown in FIGS. 1 to 3, a cover 14 is fixed to the plate 8 so as to form a space inside. One end of the screw shaft 9 extends into this space, and a driven gear 15 is fixed to this one end. A rotary shaft 23 is rotatably supported by the plate 8 and the cover 14, and a drive gear 24 meshing with the driven gear 15 is fixed to the rotary shaft 23 so as to rotate integrally therewith. The drive gear 24 is a motor 17 supported by the breakaway bracket 2 via a reduction mechanism 16 arranged in the space.
Is linked to.

The speed reduction mechanism 16 comprises a worm gear 25 and a worm wheel gear 26. The worm wheel gear 26 is attached to the rotary shaft 23 and the rotary shaft 2
3 and the drive gear 24 are fixed so as to rotate integrally. The worm gear 25 is a worm wheel gear 26.
Motor 1 that is meshed with the
It is connected to 7. As shown in FIGS. 7 to 10, the worm gear 25 is fixed to a rotary shaft 30 rotatably supported by the plate 8 via bearings 28 and 29, and is connected to the motor 17 of the rotary shaft 30. A first groove 30a is formed at the side end. Also, the motor 17
A second groove portion 31a is formed on the rotary shaft 31 of.
The coupling member 27 is movably inserted in the first groove portion 30a of the rotary shaft 30 in the radial direction so as to be inserted into the first wall portion 27a and the second groove portion 31a of the rotary shaft 31 in the radial direction. A second wall 27b that is engaged and orthogonal to the first wall 27a
Are formed respectively.

The joint member 27 has a first groove portion 30a, a first wall portion 27a, a second groove portion 31a and a second groove portion 2.
A side wall 27c that surrounds the engaging portions of the rotating shaft 30 and the rotating shaft 31 and is the outer peripheral wall of the joint member 27 is formed in a state where they are inserted and engaged with 7b. The side wall 27c is continuous with the exposed surface of the first wall portion 27a and has the first wall portion 27a.
The first notch portion 27d and the second wall portion 27 having a width wider than a
Second notches 27e each having a width wider than that of the second wall 27b and continuous with the exposed surface b are formed. A ring-shaped rubber cushion 32 is arranged on the joint member 27 thus configured so as to surround the side wall 27c in a twisted state. The rubber cushion 32 is locked in the first cutout portion 27d and the second cutout portion 27e.
On the exposed surfaces of the first wall portion 27a and the second wall portion 27b and the first biasing portion 32a and the first biasing portion 32a which are arranged at a predetermined angle with respect to the first wall portion 27a and the second wall portion 27b. Each has two urging portions 32b.

In the above structure, the rotary shaft 30 has the first
The wall portion 27a of the rotary shaft 31 is inserted into the first groove portion 30a such that the wall portion 27a is movably inserted in the radial direction so as to be coupled to the joint member 27.
The second wall portion 27b is movably inserted in the second groove portion 31a in the radial direction so as to be coupled to the joint member 27. As a result, the rotary shaft 30 is rotated by the rotary shaft 3 via the joint member 27.
1, the insertion engagement of the first wall portion 27a into the first groove portion 30a and the second groove portion 31a of the second wall portion 27b.
The torque is transmitted from the rotary shaft 31 to the rotary shaft 30 by the insertion engagement inside, and the radial movement of the first wall portion 27a in the first groove portion 30a and the second wall portion 27b. Of the rotary shaft 3 by the radial movement in the second groove portion 31a of the
The misalignment between 0 and the rotating shaft 31 is absorbed. At this time, the first
The first urging portion 32a of the rubber cushion 32 is arranged between the exposed surface of the wall portion 27a of the base member and the bottom surface of the first groove portion 30a, and the joint member 27 is rotated by the first urging portion 32a. The shaft 30 is constantly urged in the axial direction and the rotation direction. As a result, vibration between the rotary shaft 30 and the joint member 27 is effectively absorbed, and abnormal noise or the like is prevented during this period. Also, the exposed surface of the second wall portion 27b and the second groove portion 31a
The second urging portion 32b of the rubber cushion 32 is arranged between the bottom surface of the coupling member 27 and the bottom surface of the joint, and the joint member 27 is constantly urged by the second urging portion 32b in the axial direction and the rotational direction with respect to the rotating shaft 31. Energized. Thereby, the vibration between the rotary shaft 31 and the joint member 27 is effectively absorbed, and abnormal noise and the like during this period are prevented. In this way, since the vibration between the rotary shafts 30 and 31 and the joint member 27 is absorbed by the one rubber cushion 32 having a ring shape, the number of parts is small, and the cost and the number of assembling steps are small. It is very advantageous.

Next, the operation will be described.

In FIG. 1, when the motor 17 is operated, the screw shaft 9 rotates via the rotary shaft 31, the joint member 27, the rotary shaft 30, the reduction mechanism 16, the drive gear 24 and the driven gear 15. The rotation of the screw shaft 9 causes the nut member 12 to move.
It moves relative to the screw shaft 9 in the axial direction due to the screwing relationship with. The relative movement of the nut member 12 causes the upper bracket 3 and the upper main shaft 6 to rotate about the pin 4 and the universal joint with respect to the breakaway bracket 2 and the lower main shaft 5 via the link 10. .. As a result, the position of the handle 7 is adjusted as shown by the chain double-dashed line in FIG.

[0023]

According to the present invention, since the nut member is urged and deformed in the radial direction so as to be pressed and contracted toward the axial center by the slider that is wedge-engaged with the nut member,
An axial load acts on the screw shaft, and even if the nut member tries to push the nut member outwardly by this load, the load is absorbed by the wedge engagement between the slider and the nut member, and the nut member is absorbed. Is restricted from being pushed outward toward the axis. As a result, the screwing strength between the screw shaft and nut member can be improved without increasing the pressing force of the pressing member.

[Brief description of drawings]

FIG. 1 is a diagram showing a steering device that employs a drive device according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a front view of a nut member according to the present invention.

5 is a cross-sectional view taken along the line CC of FIG.

6 is a cross-sectional view taken along the line DD of FIG.

FIG. 7 is an exploded perspective view showing a connecting structure of a drive shaft and a driven shaft.

FIG. 8 is a plan view showing a connecting structure of a drive shaft and a driven shaft.

9 is a cross-sectional view taken along the line EE of FIG.

10 is a sectional view taken along line FF in FIG.

[Explanation of symbols]

 1 Breakaway Bracket (Fixed Member) 3 Atpa Bracket (Movable Member) 17 Motor (Drive Mechanism) 9 Screw Shaft 12 Nut Member 18 Slider 20 Biasing Member

Claims (1)

[Claims] 1. A screw member rotatably supported by a fixed member or a movable member and linked to a drive mechanism, a nut member supported by the fixed member or the movable member and screwed into the screw shaft, and a nut member provided on the nut member. A driving device having a pressing means for pressing and deforming the nut member in the radial direction toward the axial center so that the screw engagement with the screw shaft is strengthened, the pressing means is movable in the axial direction around the nut member. And a biasing member that biases the slider in the axial direction.