JPH0723098B2 - Electric tilt steering device - Google Patents

Description

The present invention relates to an electric tilt steering device,
In particular, the rotation transmitted from the electric motor through the speed reduction mechanism is converted into a linear motion by the screw nut mechanism, the linear motion is transmitted to the movable bracket through the link mechanism, and the movable bracket supports the fixed motion. An electric tilt steering device that tilts vertically with respect to the bracket, and a steering shaft rotatably mounted on the movable bracket and a steering wheel integrally provided on the upper end of the steering shaft tilts vertically. Regarding

[Prior art]

A device of this type has been disclosed in Japanese Patent Laid-Open No. 59-230861. Therefore, in the device disclosed in the publication, as shown in FIG. 6, each end portion of the nut 1 serves as a pair of stoppers that define the movement amount of the nut 1.
The stoppers 2a and 3a made of a single rubber are integrally provided on the rubber bands 2 and 3 for fastening the 1a and 1b from the outer circumference. Each stopper 2a, 3a has its movement restricting function by abutting on a housing 5 that supports the screw shaft 4 rotatably and immovably in the axial direction, or a support plate 7 fixed to the housing 5 with bolts 6. In addition to exerting the effect, it also exerts a shock absorbing function at the time of contact.

[Problems to be solved by the invention]

By the way, since each of the stoppers 2a and 3a described above is made of a rubber cushion material alone, when it comes into contact with the housing 5 or the support plate 7, it hardly slides on the contact surface.
Therefore, each stopper 2a, 3a receives not only a compressive force but also a twisting force each time the stoppers 2a, 3a are repeatedly brought into contact with or separated from the housing 5 or the support plate 7. Therefore, the stoppers 2a and 3a are deformed in the axial direction and the rotational direction, and it is difficult to obtain a large volume due to the restriction of the space or the like, which may "cannot be used for a long time". The above-mentioned compressive force is generated by moving the nut 1 in the axial direction of the screw shaft 4, and the twisting force is generated when the nut 1 is slightly twisted in the rotational direction of the screw shaft 4 during its movement. Axial movement and nut 1 for housing 5
Alternatively, it is caused by reversing the rotation direction of the screw shaft 4 when approaching the support plate 7 and when moving away from the support plate 7.

[Means for solving problems]

The present invention has been made to solve the above-mentioned problems, and in the above-described electric tilt steering device of the type described above, the stoppers are movably and non-rotatably held on the shaft support member as the stoppers. And a stopper capable of contacting the nut and a stopper made of a cushioning material such as rubber that is interposed between the plate and the shaft support member and elastically deforms when the plate moves in the axial direction of the screw shaft. It is characterized by having done.

[Operation of the invention]

In the present invention, the amount of movement of the nut is defined by the nut coming into contact with the plate of each stopper, and the nut exerts a pressing force on the plate along the axial direction of the screw shaft every time the nut is repeatedly brought into contact with and separated from the plate. At the same time as transmitting, it transmits the torsional force in the rotation direction. Therefore, the axial pressing force transmitted from the nut to the plate is not reduced, is transmitted to the cushion material, is relaxed by the cushion material, is transmitted to the shaft supporting member, and is received by the shaft supporting member, while the torsion transmitted from the nut to the plate is applied. The force is reduced and transmitted by the rotational slip generated between the nut and the plate, is transmitted from the plate to the shaft supporting member, and is received by the shaft supporting member, so that the plate is not rotated by the torsional force. For this reason,
Only the pressing force (compressive force) in the axial direction acts on the cushion material, and the torsional force does not act.

〔The invention's effect〕

As described above, in the present invention, since it is possible to prevent the cushion material from being twisted, the durability of the cushion material can be remarkably improved, and the nut which the cushion material cooperates with the plate to exert. It is possible to maintain the movement restriction function and the impact mitigation function of satisfactorily for a long time.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows an electric tilt steering device according to the present invention, in which a breakaway bracket 10 functioning as a fixed bracket is mounted below a body 11 constituting a dashboard.
A movable bracket 12 is attached to the upper end of 10 so as to be vertically tiltable around a shaft 13. The movable bracket 12 is configured to be tilted in the vertical direction by a drive unit A mounted on one side of the breakaway bracket 10, and has a steering shaft 15 integrally provided with a steering wheel 14 at its upper end so as to freely rotate. I support you. The steering shaft 15 is connected to a steering main shaft inserted into the column tube 16 through a universal joint provided coaxially with the shaft 13, as is well known, though not shown.

The drive unit A includes a housing 20 fixed to one side of the breakaway bracket 10 with three bottles, an electric motor 30, a reduction mechanism 40 and a screw nut mechanism 50 assembled to the housing 20, and a screw nut mechanism. The link mechanism 60 is interposed between the nut 52 of 50 and the lower end 12a of the movable bracket 12.

The electric motor 30 can be rotated normally or reversely by operating a switch (not shown), and as shown in FIG.
A worm 41 is integrally attached to the tip of the rotary shaft 31. The reduction mechanism 40 reduces the number of rotations of the rotating shaft 31 of the electric motor 30 to increase the torque and transmits this to the screw shaft 51 of the screw nut mechanism 50.
The gear includes a worm 41, a wheel 42 meshing with the worm 41, a gear 44 mounted on a shaft 43 that rotatably supports the wheel 42 in a flat width portion 43a, and a gear 45 meshing with the gear 44. 45 is attached to one end of the screw shaft 51 so as to be integrally rotatable.

The screw nut mechanism 50 is a reduction mechanism from the electric motor 30.
Rotation transmitted through 40 is converted into linear motion, and as shown in FIG.
And a nut 52 screwed onto this.
The screw shaft 51 is a thrust bearing in the housing 20.
Assembled via 53 and shim to housing 20
It is assembled to the support plate 21 fixed by two bolts 23 via the thrust bearing 54, and the housing 20
Also, it is attached to the support plate 21 so as to be rotatable and immovable in the axial direction (see FIG. 4). The nut 52 is a resin body
52a and a metallic cover 52b that surrounds it, and has a slit (not shown) along one side of the screw shaft 51. Both ends of the nut 52 are tightened from the outer circumference by a rubber ring 54 and a metal holder 55, and the main body 52a is screwed onto the screw shaft 51 without play. Both holders 55 are bands
They are connected by 56 (see FIG. 4).

As shown in FIGS. 1, 3, and 4, the link mechanism 60 controls the movement of the nut 52 to the lower end 12a of the movable bracket 12.
Links 61 and 62, which are arranged on both sides of the nut 52 and are pivotally attached at one end to bins 52c and 52d that are integrally provided on the cover 52b of the nut 52 (the outer link 61 is shown in FIG. 1). (Not shown)), and the other ends of the links 61, 62 are connected to each other and the connecting pin 63 is pivotally attached to the lower end of the movable bracket 12.

Therefore, in this embodiment, as shown in FIG. 2, the clutch mechanism 70 is interposed in the speed reduction mechanism 40.
The clutch mechanism 70 allows relative rotation between the shaft 43 and the gear 44 when the transmission torque transmitted from the shaft 43 to the gear 44 rotatably mounted on the shaft 43 reaches or exceeds a set value. As shown in FIGS. 5 and 5, the gear 43 is interposed between the collar portion 43b of the shaft 43 and one side of the gear 44, and is fitted to the two-face width portion 43c of the shaft 43 so as to be integrally rotatable.
A sliding plate 71 slidably abutting on one side, and a spring washer 72 and a nut 73 on the other side of the gear 44 and the step portion of the shaft 43.
Friction plate interposed between collars 74 that are positioned and fixed using
75, a disc spring 76 and a shim 77. The friction plate 75 has a lining 75a on one side, and the shaft 43
The two-sided width portion 43c is integrally rotatably fitted and is pressed against the other side of the gear 44 by the lining 75a. Sim 77
Is for adjusting the force of the disc spring 76 fitted to the two-sided width portion 43c of the shaft 43 so as to be integrally rotatable.
When the force of the disc spring 76 is set to a predetermined value by changing the thickness of the, and the transmission torque transmitted from the shaft 43 to the gear 44 via the sliding plate 71 and the friction plate 75 becomes equal to or greater than the set value. The sliding plate 71, the friction plate 75, and the gear 44 are slippery. The shaft 43 is rotatably supported by a push 25 press-fitted and fixed to a cover 24 fixed to the housing 20 by two screws, and the collar 74 is rotatably supported by a bush 26 press-fitted and fixed in the housing 20. ing.

Further, in this embodiment, as shown in FIGS. 3 and 4, the housing 20 is provided with the stopper 81 for restricting the leftward movement of the nut 52 in the drawing loosely fitted to the screw shaft 51.
And a stopper 82 for restricting the rightward movement of the nut 52 in the drawing are loosely fitted to the screw shaft 51 and are assembled to the support plate 21, and the movement amount of the nut 52 is It is defined by stoppers 81 and 82. Stopper 8
1 is composed of a metal plate 81a and a cushion material 81b such as rubber fixed to the plate 81a.
And the cushion member 81b is in contact with the housing 20, the left and right curled arms 81a1 and 81a1 of the plate 81a are loosely fitted in the grooves 20a and 20b of the housing 20 and the upper and lower curled parallel surfaces 81a2 thereof are inserted. , 81a2 to the bottom 20c of the housing 20
And the end flat surface 24a of the cover 24 are held by loose fitting, and are fitted to the housing 20 and the cover 24 so as to be movable in the axial direction of the screw shaft 51 and non-rotatable. Meanwhile stopper
Reference numeral 82 is a metal plate 82a and a cushion material 82b such as rubber fixed to the plate 82a.
The support plate 21 is clamped by a pair of arms 82a1 formed on the plate 82a with the cushion member 82b being in contact with the support plate 21, and the left and right curled side surfaces 82a2, 82a.
2 is guided by the inner walls 20d and 20e of the housing 20, and is fitted so as to be movable in the axial direction of the screw shaft 51 and non-rotatable.

In the present embodiment configured as described above, when a switch (not shown) is operated to rotate the electric motor 30 in the normal direction, the rotational force is transmitted from the rotation shaft 31 to the screw shaft 51, indicating the reduction mechanism 40, and the screw shaft 51 is rotated. Turns forward. As a result, the nut 52 moves to the right and the lower end 12a of the movable bracket 12 is pushed counterclockwise in FIG. 1 via the link mechanism 60. Therefore, the movable bracket 12 tilts upward about the shaft 13, and the steering wheel 14 tilts toward the top dead center shown by the phantom line in FIG. Electric motor
When 30 is reversed, the movable bracket
12 tilts downward about the shaft 13 and the steering wheel 14 tilts toward the bottom dead center shown by the phantom line in FIG.

By the way, in the present embodiment, since the clutch mechanism 70 is interposed in the reduction gear mechanism 40, the steering wheel
Steering wheel 14 and movable bracket while tilting 14
A large load acts on 12 etc., steering wheel
When 14 reaches the top dead center or the bottom dead center and the transmission torque in the reduction gear mechanism 40, that is, the transmission torque from the shaft 43 to the gear 44 becomes a set value or more, the gear 44, the sliding plate 71, and the friction plate.
The slippage occurs between 75 and the two rotate relative to each other, and the transmission torque is regulated below the set value. Therefore, the transmission torque does not become excessive, and the screw nut mechanism 50 including the electric motor 30, the reduction mechanism 40, the link mechanism 60, and the movable bracket.
Excessive power is not transmitted to 12 mag. Therefore, the steering device can be protected, and each component of the device can be made smaller and lighter, and the device can be made smaller and lighter. Further, due to the slip generated between the gear 44, the sliding plate 71, and the friction plate 75, the portion where the worm 41 and the wheel 42 mesh when the steering wheel 14 reaches the top dead center or the bottom dead center changes, Occasional impact force (each stopper 81, 82
A shock absorbing function is obtained with the clutch mechanism 70
Worm 41 and wheel)
The durability is improved without repeatedly acting on the same portion of 42. Further, in the clutch mechanism 70 of this embodiment, each member (gear 44, sliding plate 71, friction plate 75, disc spring 76, shim 77) that restricts the transmission torque is assembled between the collar portion 43b of the shaft 73 and the collar 74. Attached to other parts (wheel 42, bush 25,
26 etc.), the transmission torque of the clutch mechanism 70 is changed by assembling the shaft 43 with the clutch mechanism 70 preliminarily assembled with the housing 20 and the cover 24 together with the wheel 42 in order not to affect the manufacturing error. There is nothing to do.

Further, in the present embodiment, the movement amount of the nut 52 is defined by the stoppers 81 and 82, and when the nut 52 abuts on the stoppers 81 and 82, the end surfaces of the nut 52 are set to the stoppers 81 and 82, respectively. Abut on the plates 81a, 82a. Then, each time the nut 52 repeatedly contacts and separates from the plates 81a and 82a, the screw shaft 5 is attached to the plates 81a and 82a.
Transmits the pressing force along the axial direction of 1 and the torsional force in the rotating direction. Then, from the nut 52 to each plate 81a, 82
The axial pressing force transmitted to a is not reduced and is transmitted to each cushion material 81b, 82b, is alleviated by the cushion material 81b, 82b, and is transmitted to the housing 20 or the support plate 21.
Alternatively, the torsional force received by the support plate 21 and transmitted from the nut 52 to each plate 81a, 82a is the nut 52 and each plate 8a.
It is reduced and transmitted by the rotational slip generated between 1a and 82a, and also transmitted from each plate 81a and 82a to the housing 20 and the cover 24 or the support plate 21 to be received. Therefore, only the axial pressing force (compressing force) acts on each cushion member 81b, 82b, and the twisting force does not act. Therefore, the cushion material
The durability of 81b and 82b can be remarkably improved, and the cushion 52b and 82b work together with the plates 81a and 82a to maintain the nut 52 movement restriction function and shock absorbing function for a long time. can do.

[Brief description of drawings]

FIG. 1 is a side view of an electric tilt steering device according to the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is partly omitted along line III-III of FIG. Sectional view, 4th
1 is an exploded perspective view of an essential part of the drive unit shown in FIG. 1, FIG. 5 is an exploded perspective view of the clutch mechanism shown in FIG. 2, and FIG. 6 is a sectional view of an essential part showing a conventional example. Explanation of symbols 10 …… Breakaway bracket (fixed bracket), 12 …… Movable bracket, 14 …… Steering wheel, 15 …… Steering shaft, 20 …… Housing, 21 …… Support plate, 24 …… Cover, 30… … Electric motors,
50 …… Screw nut mechanism, 51 …… Screw shaft, 52 …… Nut, 60 …… Link mechanism, 81,82 …… Stopper, 81a, 82a …… Metal plate, 81b, 82b …… Cushion material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sumio Takizawa 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. (JP, U)

Claims (1)

[Claims] 1. A screw nut mechanism comprising a screw shaft, which is rotatably supported by a shaft support member so that rotation transmitted from an electric motor is immovable in the axial direction, and a nut which is screwed onto the screw shaft and linearly moves. The linear motion is exchanged by the, and the linear motion is transmitted to the movable bracket via the link mechanism so that the movable bracket tilts up and down with respect to the fixed bracket that supports the movable bracket, and the movable bracket is freely rotatable. The steering shaft attached to the and the steering wheel integrally provided on the upper end of the steering shaft are tilted in the vertical direction, and
In the electric tilt steering device in which the moving amount of the nut that linearly moves in the screw nut mechanism is defined by a pair of stoppers provided on both sides of the nut, as the stoppers, the shaft support member of the screw shaft is used. A plate that is axially movable but non-rotatably held and can come into contact with the nut, and is interposed between the plate and the shaft support member and elastically deforms when the plate moves in the axial direction of the screw shaft. An electric tilt steering device characterized by using a stopper made of cushioning material such as rubber.