JP2008174239A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device preventing interference of an electric motor with other devices and improving the operability of a steering wheel. <P>SOLUTION: A housing side coupler 41 and a column side coupler 51 are connected by two rivets 61. The column side coupler 51 vertically tilts in relation to the housing side coupler 41 by making an axial center of the rivet 61 as a tilt pivot TP. The tilt pivot TP is provided between the steering wheel and an electric motor 12 and in the vicinity of the electric motor 12, and thereby the electric motor 12 and motor housing 11 are not moved when adjusting the position of the steering wheel, and an oscillation space of the electric motor 12, etc. is not required to be secured around a dashboard having comparatively high device density. A distance between the tilt pivot TP and the steering wheel is taken to be comparatively large, and thereby an inclination change of the steering wheel 8 when adjusting upper and lower positions can be put in an allowable range. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric power steering apparatus, and more particularly to a technique for preventing interference between an electric motor, a gear box, and the like with another apparatus and improving operability of a steering wheel.

In a steering system for an automobile, a so-called power steering device that performs steering assist using an external power source is widely adopted.
Conventionally, a vane type hydraulic pump is generally used as a power source for a power steering apparatus, and many of these hydraulic pumps are driven by an engine. However, this type of power steering device has a large engine drive loss due to the constant drive of the hydraulic pump (several horsepower to about 10 horsepower at the maximum load), so it can be used in light vehicles with small displacement. It is difficult, and it has been unavoidable that the fuel consumption of a car with a relatively large displacement is reduced so much that it cannot be ignored. Therefore, in order to solve these problems, an electric power steering apparatus using an electric motor as a power source has attracted attention in recent years. In the electric power steering device, since the on-board battery is used as the power source of the electric motor, there is no direct engine drive loss, and the electric motor is started only at the steering assist, so that the driving fuel consumption is reduced (the engine related to the alternator In addition to being able to suppress drive loss, it has features such as extremely easy electronic control.

  On the other hand, since an automobile steering device is used (steered) by an unspecified number of drivers, it is desirable that the position of the steering wheel can be adjusted in accordance with an individual's physique and driving posture. In order to respond to such demands, not only passenger cars but also freight cars and the like are increasingly adopting a tilt mechanism. The tilt mechanism is a mechanism for adjusting the position of the steering wheel in the vertical direction, a tilt pivot for swingably supporting the steering column, and a tilt lever portion for fixing the steering column at a desired position (swing angle). Etc. The tilt mechanism has a tilt pivot in the vicinity of the connection between the steering column and the intermediate joint (waist swing tilt method), or a mechanism between the steering wheel and the steering column (swing tilt method). ) Is known.

When incorporating the tilt mechanism into the electric power steering apparatus, when the hip swing tilt method or the head tilt tilt method is employed, there are problems as described below. For example, an electric motor attached to a steering column, its gear box, and the like are relatively large and protrude in the vertical and horizontal directions. In the hip swing tilt method, this swings integrally with the steering column. As a result, it is necessary to secure a swinging space for an electric motor or the like around a dashboard having a relatively high device density, reducing the degree of freedom in designing other devices (accelerator pedal, brake pedal, etc.) It is necessary to pay close attention to fixing electric wiring connected to other electric parts. In addition, the swing tilt method has no problem related to the movement of the electric motor or the like, but the tilt of the steering wheel changes greatly at the time of position adjustment, so that there is a problem that the steering performance is deteriorated depending on the physique of the driver. .
The present invention has been made in view of the above situation, and an object of the present invention is to provide an electric power steering device that prevents interference between an electric motor or the like and another device, improves the operability of a steering wheel, and the like.

  In the present invention, in order to solve the above-mentioned problems, a steering shaft on which a steering wheel is mounted at an upper end portion, a steering column that rotatably supports the steering shaft, and a steering column attached to the steering column, In the electric power steering apparatus comprising: an electric motor provided for force assistance; and a tilt pivot that divides the steering shaft and the steering column into an upper portion and a lower portion and serves as a swing fulcrum of the upper portion. A tilt pivot provided between the steering wheel and the electric motor and in the vicinity of the electric motor is proposed.

  According to the present invention, since the tilt pivot exists directly above the electric motor, relative movement between the electric motor and the peripheral device does not occur even when adjusting the position of the steering wheel, while the distance between the steering wheel and the tilt pivot is small. Since it becomes large, the inclination of the steering wheel becomes difficult to change.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing a vehicle compartment side portion of the steering device, and reference numeral 1 in the drawing denotes a steering column. The steering column 1 includes an upper steering column (hereinafter abbreviated as “upper column”) 4 fixed to the vehicle body side member 3 via an adjusting bracket 2, and a lower steering column (hereinafter referred to as “upper steering column”) directly fixed to the vehicle body side member 3. , Which is abbreviated as a lower column). The steering device of the present embodiment incorporates an impact absorbing mechanism, and a capsule (not shown) is broken and the upper column 4 is dropped at the time of a secondary collision or the like, but the details are omitted because it becomes complicated.

  An upper steering shaft 6 is rotatably supported on the upper column 4, and a sensor output shaft 7 is rotatably supported on the lower column 5. A steering wheel 8 is attached to the upper end of the upper steering shaft 6, while a lower steering shaft 10 is connected to the lower end of the sensor output shaft 7 via a universal joint 9. Reference numeral 11 in FIG. 1 denotes a motor housing that holds and houses the electric motor 12 and a torque sensor to be described later, 13 denotes a tilt lever attached to the adjusting bracket 2, and 14 denotes an energy absorbing cover that covers the lower portion of the upper column 4. Each steel bellows is shown. Reference numeral 15 denotes a column cover that covers the upper column 4, and 16 denotes a dashboard that partitions the vehicle compartment and the engine room.

  As shown in FIG. 2 (enlarged cross-sectional view of part A in FIG. 1) and FIG. 3 (cross-sectional view taken along line BB in FIG. 2), the upper steering shaft 6 is made of synthetic resin via a joint pin 21. The ball hub 22 is swingably connected. The ball hub 22 is swingably connected to a sensor input shaft 25 of the torque sensor 24 via a pair of short pins 23 fitted at positions shifted by 90 ° from the joint pins. As a result, the upper steering shaft 6 swings with respect to the sensor input shaft 25 using the intersection of the joint pin 21 and the short pin 23 as the swing point SP, even in a state where the joint angle is within a predetermined range. A rotational force can be transmitted to the sensor input shaft 25.

  In addition to the sensor input shaft 25 described above, the torque sensor 24 moves back and forth with a slider 26 that moves in the front-rear direction (left-right direction in FIG. 2) in accordance with the relative rotation of the sensor input shaft 25 and the sensor output shaft 7. And a guide ball 28 interposed between the sensor output shaft 7 and the slider 26, a position sensor (not shown) for detecting the movement of the slider 26, and the like. The sensor input shaft 25 is connected to the sensor output shaft 7 via a torsion bar 29 so as to be relatively rotatable. Therefore, when the driver steers the upper steering shaft 6, the torsion bar 29 is twisted and the sensor input shaft 25 and the sensor output shaft 7 are rotated relative to each other, and the steering torque is detected based on the moving amount of the slider 26.

  A worm wheel 31 is fitted and fixed to the sensor output shaft 7 in the vicinity of the torque sensor 24. The worm wheel 31 meshes with a worm gear 32 connected to a rotation shaft (not shown) of the electric motor 12, and the rotation of the electric motor 12 is decelerated and transmitted to the sensor output shaft 7. In FIG. 2, reference numeral 33 denotes a ball bearing that rotatably supports the sensor output shaft 7 on the lower column 5.

  The upper steering shaft 6 includes an inner shaft 35 on the sensor output shaft 7 side and an outer shaft 36 on the steering wheel 8 side. As a result, when the driver has a secondary collision with the steering wheel 8 at the time of the collision of the automobile, the upper steering shaft 6 causes the inner shaft 35 to enter the outer shaft 36 when an axial load exceeding a predetermined value is applied. Collapse (absorb) to absorb collision energy. Similarly, the upper column 4 includes an inner tube 37 on the sensor output shaft 7 side and an outer tube 38 on the steering wheel 8 side, and collides simultaneously with the upper steering shaft 6. The above-described steel bellows 14 has a front end fixed to the inner tube 37 and a rear end fixed to the outer tube 38.

  As shown in FIG. 4 (enlarged view of portion A in FIG. 1) and FIG. 5 (viewed in the direction of arrow C in FIG. 4), the rear portion of the motor housing 11 is a steel plate press-formed product with an inverted L-shaped housing side. The coupler 41 is bolted. As shown in FIG. 6, the housing-side coupler 41 is formed with a through hole 42 in which the sensor input shaft 25 of the torque sensor 24 is loosely fitted at a portion that contacts the rear end surface of the motor housing 11, and the rear left and right sides A pair of brackets 43 extend rearward from the ends. These brackets 43 are respectively provided with pin holes 44 at positions corresponding to the swing point SP of the upper steering shaft 6 described above in a side view.

  Further, a disc-shaped column-side coupler 51 made of a steel plate press-formed product is fixed to and integrated with the inner tube 37 of the upper column 4 by welding. A pair of arms 52 extend from the left and right ends of the column side coupler 51 toward the front side in parallel, and these arms 52 have pin holes 44 provided in the bracket 43 of the housing side coupler 41. Pin holes 53 having the same diameter are formed. The left and right widths of the arms 52 of the column side coupler 51 are set to be small so as to fit inside the bracket 43 of the housing side coupler 41.

  In the case of this embodiment, the housing side coupler 41 and the column side coupler 51 are connected by two right and left rivets 61 that pass through the pin holes 44 and 53. The rivet 61 is inserted from the pin hole 44 of the housing side coupler 41, passes through the pin hole 53 of the column side coupler 51, and then crimped. In this case, the caulking is performed such that a slight gap is left between the bracket 43 and the arm 52 of both the couplers 41 and 51 so that the housing side coupler 41 and the column side coupler 51 can be relatively rotated relative to each other. ing. Thereby, the column side coupler 51 can be tilted (swinged) up and down with respect to the housing side coupler 41 with the axis of the rivet 61 as the tilt pivot TP.

  On the other hand, as shown in FIG. 7 (DD sectional view in FIG. 4), the outer tube 38 of the upper column 4 is slidably in contact with the inner side surface of the adjusting bracket 2 and has a U-shaped stay. 71 is integrated by welding. A through hole 72 is formed in the lower portion of the stay 71, and arc holes 74 and 75 are formed in the adjusting bracket 2 and a fixed stopper plate 73 fixed to the left side surface thereof. A tilt bolt 76 that constitutes a tilt adjusting mechanism passes through the through hole 72 and the circular arc holes 74 and 75 from the right side.

  The tilt bolt 76 is screwed with a nut 77 integrated with the base of the tilt lever 13, and when the tilt lever 13 is rotated counterclockwise, the spacer 78 and the moving side stopper plate 79 are interposed. Then, tighten the adjusting bracket 2 from the left and right. The stopper plates 73 and 79 are formed with anti-slipping serrations on opposite surfaces, and when the adjusting bracket 2 is tightened by the tilt bolt 76, the adjusting bracket 2 and the upper column 4 are connected to each other. Relative movement is prevented. Reference numeral 81 in FIG. 4 denotes a stopper that locks the tilt lever 13 at the upper limit position, and 82 denotes an assist spring that pulls the upper column 4 upward.

The operation of this embodiment will be described below.
When the driver rotates the steering wheel 8, the rotational force is transmitted to a steering gear (not shown) via the upper steering shaft 6, the sensor output shaft 7, and the lower steering shaft 10. The steering gear incorporates a rack and pinion mechanism or the like that converts rotational input into linear motion, and steering is performed by changing the steering angle of the wheel via a tie rod. At this time, the electric motor 12 rotates with a predetermined rotational torque in either the forward or reverse direction based on the detection signal of the torque sensor 24 in the motor housing 21, the vehicle speed, or the like, and the rotation of the electric motor 12 via the speed reduction gear. As a result, steering assist is realized.

  On the other hand, when it becomes necessary to adjust the vertical position of the steering wheel 8 due to the change of the driver, the driver first rotates the tilt lever 13 clockwise (downward). Then, the tightening by the tilt bolt 76 is released, and the serrations of the stopper plates 73 and 79 are disengaged, so that the upper column 4 swings up and down around the tilt pivot TP. When the driver raises or lowers the steering wheel 8 to adjust it to a desired position, the driver rotates the tilt lever 13 counterclockwise. Then, the tilt bolt 76 is tightened again, and the serrations of both stopper plates 73 and 79 are engaged, whereby the upper column 4 is fixed to the adjusting bracket 2. At this time, since the upper column 4 is pulled upward by the assist spring 82, the steering wheel 8 can be easily moved up and down even by a weak driver. Further, since the tilt pivot TP includes the swing point SP between the upper steering shaft 6 and the sensor input shaft 25, the steering shafts 6 and 7 can be rotated even when the vertical position of the steering wheel 8 is adjusted. Will not be disturbed.

  In the present embodiment, the tilt pivot TP is provided between the steering wheel 8 and the electric motor 12 and in the vicinity of the electric motor 12 (immediately after the motor housing 11), thereby achieving the following effects. Was obtained. That is, since the electric motor 12 and the motor housing 11 do not move when the position of the steering wheel 8 is adjusted, it is not necessary to secure a swinging space for the electric motor or the like around the dashboard having a relatively high device density. The degree of freedom in design and the like is improved, and electrical wiring to the electric motor 12, the torque sensor 24, and the like is facilitated. In addition, since the distance between the tilt pivot TP and the steering wheel 8 can be made relatively large, the tilt change of the steering wheel 8 can be allowed when adjusting the vertical position while ensuring a sufficient amount of vertical movement of the steering wheel 8. It was within the range (in this embodiment, about ± 4 ° from the neutral position).

  Although description of specific embodiment is finished above, the aspect of the present invention is not limited to the above embodiment. For example, in each of the above embodiments, the column side coupler of a steel plate press-formed product is used. However, as shown in FIG. 8, a cylindrical column side coupler 91 made of aluminum alloy or cast iron is used as the upper coupler. The inner tube 37 of the column 4 may be externally fitted and fixed, or the inner tube and the column side coupler may be integrally formed by press molding or casting. Furthermore, an electric assist mechanism or a tilt mechanism The specific configuration, the specific shape of the steering shaft, the steering column, and the like can be changed as appropriate without departing from the gist of the present invention.

[The invention's effect]
As described above, according to the electric power steering apparatus of the present invention, the steering shaft having the steering wheel mounted on the upper end portion, the steering column that rotatably supports the steering shaft, and the steering column attached to the steering column. And an electric motor for assisting the steering force of the steering wheel, and a tilt pivot that divides the steering shaft and the steering column into an upper portion and a lower portion and serves as a swing fulcrum of the upper portion. In the electric power steering apparatus, since the tilt pivot is provided between the steering wheel and the electric motor and in the vicinity of the electric motor, the electric motor or the like does not move when the position of the steering wheel is adjusted. , With design flexibility such Rupedaru and the brake pedal is improved, while securing a sufficient vertical movement of the steering wheel, it is possible to reduce the inclination change of the steering wheel at the time of vertical position adjustment.

It is explanatory drawing which shows the structure in the compartment side of the steering device which concerns on this invention. It is the A section expanded sectional view in FIG. It is BB sectional drawing in FIG. It is the A section enlarged view in FIG. It is C arrow line view in FIG. It is a disassembled perspective view of a housing side coupler, a column side coupler, etc. It is DD sectional drawing in FIG. It is a disassembled perspective view which shows embodiment which changed the structure partially.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Steering column 2 ... Adjusting bracket 4 ... Upper column 5 ... Lower column 6 ... Upper steering shaft 7 ... Sensor output shaft 8 ... Steering wheel 11 ... Motor housing 12 ... Electric motor 13 ... Tilt lever 35 ... Inner shaft 37 ... Inner column 41 ... Housing side coupler 43 ... Bracket 51 ... Column side coupler 52 ... Arm 61 ... Rivet SP ... Swing point TP ... Tilt pivot

Claims (1)

A steering shaft with a steering wheel mounted on the upper end, and
A steering column that rotatably supports the steering shaft;
An electric motor attached to the steering column and used for assisting the steering force of the steering wheel;
In the electric power steering apparatus, the steering shaft and the steering column are divided into an upper portion and a lower portion, and a tilt pivot serving as a swing fulcrum of the upper portion is provided.
An electric power steering apparatus, wherein the tilt pivot is provided between the steering wheel and the electric motor and in the vicinity of the electric motor.

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