JPH0464909B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric tail steering device, and in particular, to convert rotation transmitted from an electric motor through a reduction mechanism into a linear motion using a screw nut mechanism. The steering shaft is rotatably assembled to the movable bracket, and the steering shaft is integrally attached to the upper end of the movable bracket. The present invention relates to an electric tilt steering device in which a steering wheel provided in the vehicle tilts in the vertical direction.

[Prior art]

This type of device has been disclosed in Japanese Patent Application Laid-Open No. 59-230861. However, the device disclosed in the publication is not provided with any means for regulating the transmitted torque.

[Problem that the invention seeks to solve]

Therefore, in the conventional device described above, when the steering wheel or the like reaches the top or bottom dead center, the transmitted torque becomes excessive and excessive force acts on the constituent members of the device.

[Means for solving problems]

The present invention has been made to solve the above-mentioned problems, and in the above-mentioned electric tail steering device, one gear constituting the reduction mechanism is rotatable with respect to its support shaft, and both sides of the gear are A sliding plate and a friction plate are disposed in surface contact over substantially the entire area of the side surface and are assembled to the support shaft so as to be able to rotate integrally, and the sliding plate and the friction plate are attached to both sides of the gear by a spring member. The clutch mechanism is configured such that when the transmission torque in the speed reduction mechanism exceeds a set value, slipping occurs between the sliding plate and the friction plate and the gear.

[Operations and Effects of the Invention] In the present invention, when the transmission torque in the reduction mechanism exceeds a set value, slipping occurs between the sliding plate and friction plate constituting the clutch mechanism and the gear, causing them to rotate relative to each other. Then, the transmission torque is regulated below the set value. Therefore, the transmitted torque does not become excessive, and excessive force is not transmitted from the electric motor, reduction mechanism, etc. to the movable bracket, etc. Therefore, the device can be protected, and each component of the device can be made smaller and lighter, so the device can be made smaller and lighter.

Further, in the present invention, the clutch mechanism is a sliding member that is rotatably assembled to a gear constituting the reduction mechanism and a shaft that supports this gear, and that is in surface contact with both side surfaces of the gear over substantially the entire area of the side surfaces. It has a structure including a plate and a friction plate, and is installed in the speed reduction mechanism on the input side of the screw nut mechanism. As a result, not only can the clutch mechanism be constructed easily and inexpensively by effectively utilizing the constituent members of the speed reduction mechanism, but also the transmission torque of the clutch mechanism can be stabilized at a large transmission torque. The clutch mechanism can be operated in the same way both in forward and reverse rotation of the electric motor. In addition, since the screw nut mechanism is located on the output side of the clutch mechanism, it is possible to accurately prevent the steering wheel from moving when a load is applied to the steering wheel, such as when the driver touches the steering wheel. can.

〔Example〕

An embodiment of the present invention will be described below based on the drawings. FIG. 1 shows an electric tail steering device according to the present invention, in which a breakaway bracket 10 functioning as a fixed bracket is attached below a body 11 constituting a dash board, and a breakaway bracket 10 is attached to the upper end of the bracket 10. A movable bracket 12 is assembled so as to be tiltable up and down about a shaft 13. The movable bracket 12 is tilted vertically by a drive device A attached to one side of the breakaway bracket 10, and is capable of freely rotating a steering shaft 15 that integrally includes a steering wheel 14 at its upper end. It is pivoted on. Although not shown, the steering shaft 15 is connected to a steering main shaft inserted into the column tube 16 via a universal joint provided coaxially with the shaft 13, as is well known.

Drive device A is breakaway bracket 1
A housing 20 fixed to one side of the housing 20 with three bolts, an electric motor 30, a speed reduction mechanism 40, a screw nut mechanism 50 assembled to the housing 20, and a nut 52 of the screw nut mechanism 50. and a link mechanism 60 interposed between the lower end 12a of the movable bracket 12.

The electric motor 30 can rotate forward or reverse by operating a switch (not shown), and as shown in FIG. 2, a worm 41 is integrally assembled at the tip of its rotating shaft 31. . The speed reduction mechanism 40 reduces the rotation speed 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, and includes a worm 41, a wheel 42 meshing with the worm 41, and a wheel 42 meshing with the worm 41. The wheel 42 is configured by a gear 44 assembled on a shaft 43 that rotatably supports the wheel 42 at a width across flats portion 43a, and a gear 45 that meshes with the shaft 43, and the gear 45 is connected to one end of the screw shaft 51. It is assembled so that it can rotate integrally with the section.

The screw nut mechanism 50 is driven by the electric motor 30
It converts the rotation transmitted from the motor through the speed reduction mechanism 40 into linear motion, and as shown in FIG. 3, it is composed of a screw shaft 51 and a nut 52 screwed onto this There is. The screw shaft 51 is assembled to the housing 20 via a thrust bearing 53, and is also attached to the support plate 21 fixed to the housing 20 via a shim 22 with two bolts 23 via a thrust bearing 54. It is assembled to the housing 20 and the support plate 21 so as to be rotatable but immovable in the axial direction (see FIG. 4). The nut 52 includes a main body 52a made of resin and a cover 5 made of metal surrounding the main body 52a.
2b, and has a slit (not shown) along the screw shaft 51 on one side.
Both ends of the nut 52 are tightened from the outer periphery by a rubber ring 54 and a metal holder 55, so that the main body 52a is screwed onto the screw shaft 51 without play. Note that both holders 55 are connected by a band 56 (see FIG. 4).

As shown in FIGS. 1, 3, and 4, the link mechanism 60 transmits the movement of the nut 52 to the lower end 12a of the movable bracket 12, and is arranged on both sides of the nut 52. links 61 and 62 (the outer link 61 is shown only in FIG. 1), one end of which is pivotally connected to pins 52c and 52d integrally provided on the cover 52b;
It is constituted by a connecting pin 63 which connects the other ends of the links 61 and 62 to each other and pivotally connects them to the lower end of the movable bracket 12.

Therefore, in this embodiment, as shown in FIG.
is interposed. The clutch mechanism 70 allows relative rotation between the shaft 43 and the gear 44 when the transmission torque transmitted between the shaft 43 and the gear 44 rotatably assembled on the shaft 43 exceeds a set value. As shown in FIG. 2 and FIG.
a sliding plate 71 that is integrally rotatably fitted to the gear 44 and slidably abuts on one side of the gear 44; and a spring washer 72 on the other side of the gear 44 and the stepped portion of the shaft 43.
Collar 7 is positioned and fixed using nuts 73 and
It is composed of a friction plate 75, a disc spring 76, and a shim 77 interposed between the four. The friction plate 75 has a lining 75a on one side, and the shaft 43
It is fitted in the width across flats portion 43c so as to be integrally rotatable, and is pressed against the other side of the gear 44 by a lining 75a. The shim 77 is for adjusting the force of the disc spring 76 that is integrally rotatably fitted to the width across flats portion 43c of the shaft 43. By changing the thickness of the shim 77, the force of the disc spring 76 can be adjusted to a predetermined value. When the transmission torque transmitted from the shaft 43 to the gear 44 via the sliding plate 71 and the friction plate 75 exceeds the set value, there is a Slippage is starting to occur. The shaft 43 is rotatably supported by a bush 25 that is press-fitted into a cover 24 that is fixed to the housing 20 with two screws.
Further, the collar 74 is rotatably supported by a bush 26 press-fitted into the housing 20.

Further, in this embodiment, as shown in FIGS. 3 and 4, the housing 20 and the cover are in a state in which the stopper 81 that restricts the leftward movement of the nut 52 in the drawings is loosely fitted to the screw shaft 51. 24, and a stopper 82 that restricts the rightward movement of the nut 52 in the figure is assembled to the support plate 21 while being loosely fitted to the screw shaft 51. 81 and 82. The stopper 81 consists of a metal plate 81a and a cushioning material 81b such as rubber fixed to the metal plate 81a.The stopper 81 is made of a metal plate 81a and a cushioning material 81b such as rubber fixed to the metal plate 81a. The screw shaft 51 is fitted into the housing 20 and the cover 24 so as to be movable in the axial direction of the screw shaft 51 but not rotatable. On the other hand, the stopper 82 includes a metal plate 82a and a cushion material 8 such as rubber fixed to the metal plate 82a.
2b, plate 82a is connected to nut 5.
2 side and with the cushion material 82b in contact with the support plate 21, a pair of arms 82a1 formed on the plate 82a are fitted to the support plate 21 so as to be movable in the axial direction of the screw shaft 51 but not rotatable. ing.

In this embodiment configured as described above, when the electric motor 30 is rotated in the normal direction by operating a switch (not shown), rotational force is transmitted from the rotary shaft 31 to the screw shaft 51 via the reduction mechanism 40, and the screw shaft 51 is rotated. The shaft 51 rotates normally. This results in
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
is tilted upward about the shaft 13, and the steering wheel 14 is tilted toward the top dead center indicated by the imaginary line in FIG. Moreover, when the electric motor 30 is reversed, the movable bracket 1
2 tilts downward about the shaft 13, and the steering wheel 14 tilts toward the bottom dead center indicated by the imaginary line in FIG.

By the way, in this embodiment, the speed reduction mechanism 40
Since the clutch mechanism 70 is interposed therein, a large load may be applied to the steering wheel 14, the movable bracket 12, etc. while the steering wheel 14 is tilting, or the steering wheel 14 may reach top dead center or bottom dead center. , when the transmission torque in the reduction mechanism 40, that is, the transmission torque from the shaft 43 to the gear 44, exceeds the set value, the gear 44
Sliding occurs between the sliding plate 71 and the friction plate 75, causing them to rotate relative to each other, and the transmitted torque is regulated to be below a set value. Therefore, the transmitted torque does not become excessive, and excessive force is not transmitted from the electric motor 30, deceleration mechanism 40, etc. to the screw nut mechanism 50, link mechanism 60, movable bracket 12, etc. Therefore, the steering device can be protected, and each component of the device can be made smaller and lighter.
Weight reduction can be achieved. Also, the gear 4 mentioned above
4, the sliding plate 71, and the friction plate 75, when the steering wheel 14 reaches the top dead center or the bottom dead center, the worm 41 and the wheel 4
Since the meshing parts of the worm 41 and the wheel 42 are different, the impact force generated when the worm 41 and the wheel 42 are applied (which is relatively small because the stoppers 81 and 82 provide a shock mitigation function and the clutch mechanism 70 operates) is the same. The durability of the area is improved as it does not act on the area repeatedly. Furthermore, the clutch mechanism 70 of this embodiment includes various members (gear 44, sliding plate 71, friction plate 75, disc spring 76,
The shim 77) is assembled between the flange 43b of the shaft 43 and the collar 74 to prevent manufacturing and assembly errors of other parts (wheel 42, bushes 25, 26, etc.) from affecting the clutch. The shaft 43 with the mechanism 70 assembled in advance is attached to the wheel 42.
At the same time, by assembling the clutch mechanism 70 to the housing 20 and the cover 24, the transmission torque of the clutch mechanism 70 does not change.

Further, in this embodiment, the clutch mechanism 70
However, friction occurs between the single gear 44 constituting the reduction mechanism 40 and the sliding plate 71 that is rotatably assembled to the shaft 43 that supports the gear 44 and makes surface contact with both side surfaces of the gear 44 over substantially the entire area of the side surfaces. The plate 75 is provided in the speed reduction mechanism 40 on the input side of the screw nut mechanism 50. As a result, the clutch mechanism 70 can be constructed easily and inexpensively by effectively utilizing the constituent members of the speed reduction mechanism 40, and the transmission torque of the clutch mechanism 70 can be stabilized at a large transmission torque. In addition, the clutch mechanism 70 can be operated in the same manner both when the electric motor 30 rotates in the forward direction and in the reverse direction. Further, a screw nut mechanism 50 is provided on the output side of the clutch mechanism 70.
Therefore, the movement of the steering wheel 14 can be accurately prevented when a load is applied to the steering wheel 14, such as when a driver or the like touches the steering wheel 14 with their hands.

Further, in this embodiment, the amount of movement of the nut 52 is regulated by the stoppers 81 and 82, and when the nut 52 comes into contact with each stopper 81 and 82, each end surface of the nut 52 moves toward each stopper 81 and 82.
1 and 82 plates 81a and 82a.
By the way, the nut 52 has each plate 81a, 82
Each time the contact and separation from a is repeated, each plate 8
A pressing force along the axial direction of the screw shaft 51 is transmitted to 1a and 82a, and a torsional force in the rotational direction is transmitted. Therefore, each plate 8 from nut 52
The axial pressing force transmitted to 1a, 82a is transmitted to each cushion material 81b, 81b without decreasing, is relaxed by the cushion materials 81b, 82b, is transmitted to housing 20 or support plate 21, and is transmitted to housing 20 or support plate 21. On the other hand, the torsional force transmitted from the nut 52 to each plate 81a, 82a is received by the nut 52 and each plate 81a, 82a.
It is transmitted in a reduced manner due to the rotational slippage that occurs between them, and is transmitted from each plate 81a, 82a to the housing 20 and the cover 24 or the support plate 21, where it is received. For this reason, each cushion material 81b, 82
Only axial pressing force (compressive force) acts on b, and no torsional force acts on it. Therefore, the cushion material 8
1b, 82b can be significantly improved, and each cushion material 81b, 82b works together with each plate 81a, 82a.
The movement regulation function and impact mitigation function of 2 can be maintained satisfactorily for a long period of time.

[Modification] In the above embodiment, the clutch mechanism 70 is interposed between the shaft 43 and the gear 44 of the reduction mechanism 40. It is also possible to implement the present invention.

[Brief explanation of the drawing]

FIG. 1 is a side view of the electric tail steering device according to the present invention, FIG. 2 is a sectional view taken along line - in FIG. 1, and FIG. 3 is a partially omitted sectional view taken along line - in FIG. 4 is an exploded perspective view of essential parts of the drive device shown in FIG. 1, and FIG. 5 is an exploded perspective view of the clutch mechanism shown in FIG. 2. Explanation of symbols, 10... Breakaway bracket (fixed bracket), 12... Movable bracket, 14... Steering wheel, 15... Steering shaft, 30... Electric motor, 40
... Reduction mechanism, 43 ... Shaft (support shaft), 44 ... Gear, 50 ... Screw nut mechanism, 70 ... Clutch mechanism, 71 ... Sliding plate,
75...Friction plate, 76... Disc spring (spring member).

Claims (1)

[Claims] 1 The rotation transmitted from the electric motor via the reduction mechanism is converted into linear motion by the screw nut mechanism and transmitted to the movable bracket, which tilts vertically relative to the fixed bracket that supports it. In the electric tail steering device, the deceleration mechanism is configured such that a steering shaft rotatably assembled to the movable bracket and a steering wheel integrally provided at the upper end of the steering shaft are tilted in the vertical direction. A gear is made rotatable with respect to its support shaft, and a sliding plate and a friction plate are arranged on both sides of the gear and are in surface contact over substantially the entire area of the sides, and these are assembled to the support shaft so that they can rotate integrally. Further, the sliding plate and the friction plate are engaged with both sides of the gear by a spring member, so that when the transmission torque in the reduction mechanism exceeds a set value, the sliding plate and the friction plate are engaged with each other by a spring member. An electric tail steering device comprising a clutch mechanism that causes slippage between the gears and the gears.