JP2002114157A - Shock absorbing type steering column device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorbing type steering column device for previously changing the amount of absorbing secondary collision energy before a collision by estimating the collision. SOLUTION: An ECU 37 and a car speed sensor 39 are installed between a dash panel 33 and an instrument panel 35, and a detection signal of the car speed sensor 39 is transmitted to the ECU 37. A member designated by a reference numeral 36 is a radar type or infrared type range sensor mounted in a front grille, which always measures the distance between a preceding vehicle or an obstacle and a driver's own vehicle, and transmits the detection signal to the ECU 37. The ECU 37 repeatedly estimates a collision at designated control intervals according to a detection signal of the range sensor 36 and a detection signal of the car speed sensor 38, and controls the drive of a variable collision energy absorbing mechanism 49.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock-absorbing steering column device, and more particularly to a technique for predicting a collision to change the amount of secondary collision energy absorbed before a collision.

[0002]

2. Description of the Related Art When an automobile collides with another automobile, a building, or the like, the driver sometimes makes a secondary collision with the steering wheel due to inertia. In recent years, shock absorbing steering shafts and shock absorbing steering column devices have been widely used in passenger cars and the like in order to prevent the driver from being injured in such a case. In the shock absorbing type steering column device, when a driver makes a secondary collision, the steering column falls off together with the steering shaft. Usually, the steering column collapses simultaneously with the steering shaft, and at that time, collision energy is absorbed. As described in JP-B-46-35527, a metal sphere is interposed between the outer column and the inner column so that the inner peripheral surface of the outer column and the inner column during the collapse are collapsed. Ball type to form a plastic groove on the outer peripheral surface of
As described in JP-A-7-329796, an energy absorbing member such as a steel plate is held on one of the outer column and the inner column, and the energy is absorbed by an ironing means such as an ironing pin held on the other. It is known that the absorbing member is hardened and ironed.

[0003]

In the above-described shock absorbing type steering column apparatus, the steering column collapses when a predetermined collapse load is applied. However, the following problem arises due to this. I was Usually, the collapse load is set based on the kinetic energy of a driver having a standard weight colliding with the steering wheel at a predetermined speed. However, when the driver is a small woman or the like, the kinetic energy is naturally reduced. Therefore, even if such a driver collides with the steering wheel at the same speed, the steering column does not collapse, and the collision energy is not increased. Absorption is not performed at all. As a result, the shock-absorbing steering column device cannot perform its intended function, and the driver may receive a large shock on the chest or head.

In order to deal with such a problem, British Patent GB 2340457A has a hydraulic cylinder type collision energy absorbing means, and an electronic control unit (ECU) is provided with operating parameters output from a vehicle speed sensor, a driver weight sensor and the like. A target collapse load is calculated on the basis of the above, and the collapse load is switched by changing the hydraulic oil inflow resistance of the hydraulic cylinder by adjusting the opening / closing amount of an electric valve provided in the hydraulic circuit of the collision energy absorbing means. ing. However, this device still has the following problem in the timing of switching the collapse load. Generally, in order to avoid the impact received by the occupant, it is necessary that the switching of the lap load in the collision energy absorbing means has been completed before the occupant collides with the deployed airbag. However, electric valves and electromagnetic actuators require a relatively long time from the start to the end of operation due to their structure. Therefore, even if a drive current is input from the ECU that detects the collision, the occupant starts to operate the airbag from the point of collision of the vehicle. It is not possible to switch the collapse load in a very short time before colliding with the vehicle. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an impact-absorbing steering column device that predicts a collision and changes the amount of absorbed secondary collision energy before the collision.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the first aspect of the present invention, a shock absorbing steering system provided with a collision energy absorbing means for absorbing a secondary collision energy of an occupant in a vehicle collision. A column device, a distance detecting means for detecting a distance to an object existing in front of the own vehicle, a speed detecting means for detecting a traveling speed of the own vehicle, and the secondary collision energy Energy absorption amount adjustment means for changing the absorption amount; collision prediction means for predicting a collision between the own vehicle and the object based on the detection results of the distance detection means and the speed detection means; In the case where a collision with the object is predicted, a driving control unit for driving and controlling the energy absorption amount adjusting unit in advance before the collision is proposed.

In the present invention, when the collision prediction means predicts a sudden approach of a preceding vehicle or the like from the detection results of the distance detection means and the speed detection means, the drive control means having received the prediction result,
The amount of secondary collision energy absorption is set based on the relative speed with the preceding vehicle and the like, and a drive current is output to the actuator of the energy absorption amount adjusting means before the actual collision occurs.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a passenger compartment of a passenger car according to an embodiment, and reference numeral 1 in the figure denotes a steering device. The steering device 1 includes a steering column 7 attached to a vehicle body-side member 2 via a tilt bracket 3 and a lower bracket 5, an upper steering shaft 9 rotatably held in the steering column 7, and an upper steering shaft. 9 and a universal joint 1 at the lower end of the upper steering shaft 9.
The lower steering shaft 15 and the like are connected to each other via the lower steering shaft 3. In FIG. 1, a member indicated by reference numeral 17 is a steering pad provided at the center of the steering wheel 11, and accommodates an airbag, an inflator 18 for deploying the airbag, and the like. Reference numeral 19
The member indicated by is a column cover, and the member indicated by reference numeral 20 is a tilt lever.

In this steering system, when the driver 21 rotates the steering wheel 11, the upper steering shaft 9 and the lower steering shaft 1
The rotational force is transmitted to a steering gear (not shown) via the control unit 5. The steering gear has a built-in rack-and-pinion mechanism that converts a rotational input into a linear motion, and the steering is performed by changing the steering angle of the wheel via a tie rod or the like. Various types of steering gears such as a ball screw type and a worm roller type are known in addition to the rack and pinion type.

The driver 21 sits on the driver's seat 25 attached to the floor pan 23 and the seat belt 2
7 restrains the seat 25. Sheet 25
Moves back and forth along a seat rail 29 fixed to the floor pan 23, and the angle of the backrest 31 can be adjusted according to the riding posture of the driver 21. Dash panel 33 and instrument panel 35
An ECU 37 and a vehicle speed sensor 39 are provided between the ECU and the ECU 37, and a detection signal of the vehicle speed sensor 39 is transmitted to the ECU 37. In FIG. 1, a member indicated by reference numeral 36 is a radar-type or infrared-type distance sensor installed in a front grill (not shown) or the like, and constantly measures the distance between a preceding vehicle, an obstacle, and the like and the own vehicle. The detection signal is transmitted to the ECU 37. A member indicated by reference numeral 38 is a seat belt pretensioner, which operates with gas generated by a built-in gas generator 40 and winds up the seat belt 27 with a predetermined tension. The inflator 18 for deploying the airbag and the gas generator 40 for the seatbelt pretensioner 38 are both connected to the ECU 37.

FIG. 2 is a side view of the steering column 7, and FIG. 3 is an enlarged view of a portion A in FIG. As shown in these figures, the steering column 7 has an outer column 41 and an inner column 43 both made of steel pipe, and a distance bracket 45 welded to the outer column 41.
And a variable collision energy absorbing mechanism 49 as main components. In the case of the present embodiment, the distance bracket 45 is held by the tilt bracket 3 and detaches forward from the vehicle body side member 2 together with the tilt bracket 3 when a predetermined forward load is applied. In FIG. 2, a member denoted by reference numeral 50 is a capsule made of an aluminum alloy or the like, and is fixed to the tilt bracket 3 with a predetermined fastening force by resin injection. The member denoted by reference numeral 51 is a rubber bush interposed between the lower bracket 5 and the inner column 43, and absorbs the swing of the steering column 7 at the time of tilt.

As shown in FIGS. 3 and 4 (viewed in the direction of arrow B in FIG. 3), the variable collision energy absorbing mechanism 49 is provided between the outer column 41 and the inner column 43 by a first type. A metal ball holding tube 61, a second metal ball holding tube 63 disposed in front of the first metal ball holding tube 61, and a holding tube locking device 65 for locking the second metal ball holding tube 63. Are the main constituent members.

Each of the first metal ball holding cylinder 61 and the second metal ball holding cylinder 63 is made of a synthetic resin, a sintered oil-impregnated alloy, or the like, and holds steel balls 67, 69 rotatably, respectively. In the case of the present embodiment, the first metal ball holding cylinder 61 and the second metal ball holding cylinder 63 are connected with a predetermined engaging force by engaging claws (not shown), but are connected by a resin shear pin or the like. Is also good.

The outer diameters of the steel balls 67 and 69 are set to be larger than the gap between the outer column 41 and the inner column 43 by a predetermined amount, and when the outer column 41 and the inner column 43 relatively move in the axial direction. Plastic grooves are formed on the inner and outer peripheral surfaces of both columns 41 and 43. The steel ball 67 on the first metal ball holding cylinder 61 side and the steel ball 69 on the second metal ball holding cylinder 63 side
Is different in angular phase in the rotation direction.

The holding cylinder locking device 65 includes an outer column 41.
A housing 71 made of an aluminum alloy, a synthetic resin, steel or the like fixed to the housing, a push-type electromagnetic actuator (hereinafter referred to as a solenoid) 73 held by the housing 71 and driven and controlled by the ECU 37, and a solenoid 73 It comprises a locking projection 77 formed at the tip of the plunger 75, a compression coil spring 79 for urging the plunger 75 downward in FIG. A through hole 81 is formed in the second metal ball holding cylinder 63, and the locking projection 77 fits into the through hole 81 when the plunger 75 projects.

In the case of this embodiment, a slit 83 is formed in the rear part of the housing 71, and the housing 71 is fixed to the outer column 41 by tightening a bolt 85. The housing 71 has a positioning protrusion 87.
The inside end of the positioning protrusion 87 is fitted into a locking hole (not shown) formed in the outer column 41, thereby positioning the housing 71 with respect to the outer column 41 and preventing rotation. When the housing 71 is fixed to the outer column 41, the housing 71 is formed into a cylindrical shape whose inner diameter is smaller than the outer diameter of the outer column 41 by a predetermined amount, and then the outer column 41 is fixed.
May be adopted.

The operation of the embodiment will be described below. When the vehicle starts running, the ECU 37 repeatedly performs a collision prediction at a predetermined control interval based on the detection signal of the distance sensor 36 and the detection signal of the vehicle speed sensor 39. That is, the ECU 37 determines whether the preceding vehicle is in an obstacle state when the distance to the own vehicle is reduced in a short time due to rapid braking of the preceding vehicle, or when a load dropped from a freight car or the like appears on the course of the own vehicle. From the rate of decrease in the distance to the object and the traveling speed of the own vehicle, the possibility of a collision is determined using a predetermined arithmetic expression. Then, when it is determined that the possibility of collision is high, the ECU 37 obtains, based on the detection signal of the distance sensor 36 and the detection signal of the vehicle speed sensor 39,
The time margin until the collision and the strength of the collision are estimated, and the target collapse load of the steering column 7 is calculated.

When the estimated collision is stronger than a predetermined value, the kinetic energy of the driver 21 at the time of the collision becomes large, so that the target collapse load calculated by the ECU 37 also becomes large. Then, the ECU 37 does not output a drive current to the solenoid 73 of the variable collision energy absorbing mechanism 49, and as a result, as shown in FIG.
The urging force keeps the plunger 75 at a lower position in the figure, and does not allow the locking projection 77 to fit into the through hole 81 of the second metal ball holding cylinder 63.

When a vehicle collides with another vehicle or an obstacle on the road in this state, the ECU 37 supplies an ignition current to the inflator 18 for deploying the airbag and the gas generator 40 of the seat belt pretensioner 38. Then, at the same time when the airbag is deployed and inflated, the seatbelt 27 wound around the seatbelt pretensioner 38 is opened.
As a result, the driver 21 is securely restrained by the seat 31. This prevents the collision of the driver 21 with the steering wheel 11 and also suppresses unnecessary movement of the driver 21.

After the airbag is deflated, the driver 21 collides with the steering wheel 11 due to its inertia, and the steering wheel 11 is pressed forward. Then, the tilt bracket 3 separates from the capsule 50 (that is, the vehicle body member 2) forward, and as shown in FIG.
When the inner column 43 enters the outer column 41, the steering column 7 starts to collapse.

At this time, in this embodiment, since the first metal ball holding cylinder 61 and the second metal ball holding cylinder 63 are connected, the two metal ball holding cylinders 61 and 63 are integrally formed as an inner column. The outer column 41 advances between the outer column 41 and the inner column 43 by a half of the amount of movement of the 43. Accordingly, plastic grooves formed by the steel balls 67 on the first metal ball holding cylinder 61 side and the steel balls 69 on the second metal ball holding cylinder 63 side are formed on the inner peripheral surface of the outer column 41 and the outer peripheral surface of the inner column 43. Are formed, and a relatively large impact energy absorption is realized. FIG. 6 is a graph showing the relationship between the movement stroke of the outer column 41 and the collapse load, and the solid line in FIG. 6 shows the test result at this time (at the time of a large collapse load).

On the other hand, when the estimated collision is weaker than the predetermined value, the kinetic energy of the driver 21 at the time of the collision becomes relatively small, so that the target collapse load calculated by the ECU 37 also becomes small. Then, the ECU 37 determines in advance the solenoid 7 of the variable collision energy absorbing mechanism 49 before the collision.
7, the plunger 75 is moved upward in the figure against the urging force of the compression coil spring 79, as shown in FIG. It is fitted into the through hole 81 of the ball holding cylinder 63.

In this state, if the vehicle collides with another vehicle or an obstacle on the road, the outer column 41 is dropped by the secondary collision of the driver 21 with the steering wheel 11 by the same process as described above. The steering column 7 starts the collapse. At this time, since the second metal ball holding cylinder 63 is locked by the locking projection 77 of the plunger 75, it enters the outer column 41 together with the first metal ball holding cylinder 61 as shown in FIG. No (the two metal ball holding cylinders 61, 63 overcome
Is separated), only the plastic groove formed by the steel ball 67 on the first metal ball holding cylinder 61 side is formed, and the absorption amount of impact energy is relatively small. As a result, even if the collision is relatively weak, the collapse of the steering column 7 is performed smoothly, and a large impact is not applied to the chest and head of the driver 21. The broken line in FIG. 6 shows the test result at this time (at the time of a small collapse load), and it is understood that the small collapse load is significantly smaller than the large collapse load.

The description of the specific embodiment has been completed.
The aspects of the present invention are not limited to the above embodiment.
For example, in the absorption energy changing means of the above embodiment, the first metal ball holding cylinder and the second metal ball holding cylinder are separated from each other by engaging the second metal ball holding cylinder with the outer column by the electromagnetic actuator. Although the load is changed, a combination of an electric motor and a screw mechanism or the like may be used, or an electric ignition type gas generator used for an airbag or the like may be used. Further, by appropriately setting the arrangement and the like of the steel ball holding holes formed in the two metal ball holding cylinders, the amount of change in the collapse load can be freely set, and can be changed in three or more stages. is there.

Further, as the energy absorbing means, a method of bending, breaking or ironing a steel plate or the like may be employed, and in such a case, the collapse load is adjusted steplessly by the variable absorbing energy means. It is also possible. Further, in the above embodiment, when it is determined that the possibility of collision is large, the ECU performs the drive control of the energy absorption amount adjusting means by estimating the strength (impact degree) of the collision. May be performed according to the weight and physique of the person, the distance from the steering wheel, and the like. In addition, the specific configuration of the steering column device and the absorption energy varying means and the specific shape of the metal ball holding cylinder and the like can be appropriately changed without departing from the gist of the present invention.

[0025]

As described above, according to the present invention, there is provided an impact-absorbing steering column device provided with a collision energy absorbing means for absorbing a secondary collision energy of an occupant at the time of a vehicle collision. Distance detecting means for detecting the distance to an object existing in the vehicle, speed detecting means for detecting the traveling speed of the host vehicle, and energy absorbing amount adjusting means for changing the amount of the secondary collision energy absorbed by the collision energy absorbing means And, collision prediction means for predicting a collision between the own vehicle and the object from the detection results of the distance detection means and the speed detection means, when the collision prediction means predicts a collision between the own vehicle and the object, A drive control unit for driving and controlling the energy absorption amount adjusting unit before the collision is provided, so that the collision prediction unit detects the detection result of the distance detection unit and the speed detection unit. When predicting the approaching rapidly the like et preceding vehicle, the drive control means receives the prediction result, set the absorption amount of the secondary collision energy from the relative speed between the preceding vehicle and the like,
By outputting the drive current to the actuator of the energy absorption amount adjusting means before the collision actually occurs, it is possible to prevent the operation delay of the energy absorption amount adjusting means and to obtain an appropriate collapse load at the time of the collision.

[Brief description of the drawings]

FIG. 1 is a side view showing a passenger compartment of a passenger car according to an embodiment.

FIG. 2 is a side view of a steering column.

FIG. 3 is an enlarged view of a portion A in FIG. 2;

FIG. 4 is a view as seen from the arrow B in FIG. 3;

FIG. 5 is an explanatory view showing the operation of the holding cylinder locking device when a large collapse load is applied.

FIG. 6 is a graph showing a relationship between a movement stroke of an outer column and a collapse load.

FIG. 7 is an explanatory diagram showing the operation of the collision energy absorbing mechanism during a small collapse load.

FIG. 8 is an explanatory diagram showing the operation of the collision energy absorbing mechanism during a small collapse load.

[Explanation of symbols]

1 Steering device 3 Tilt bracket 5 Lower bracket 7 Steering column 11 Steering wheel 18 Inflator (for airbag) 21 Driver 25 Seat 36 Distance sensor 37 ‥ ECU 38 ‥‥ Seat belt pretensioner 39 ‥‥ Vehicle speed sensor 40 ‥‥ Gas generator (for seat belt pretensioner) 41 ‥‥ Outer column 43 ‥‥ Inner column 45 ‥‥ Distance bracket 49 ‥‥ Variable collision energy absorption mechanism 61 ‥‥ first metal ball holding cylinder 63 ‥‥ second metal ball holding cylinder 65 ‥‥ holding cylinder locking device 67,69 ‥‥ steel ball 71 ‥‥ housing 73 ‥‥ solenoid 75 ‥‥ plunger 77 ‥‥ locking Projection 79 ‥‥ Compression coil spring 81 ‥‥ Through hole

Claims (1)

[Claims] An impact-absorbing steering column device provided with a collision energy absorbing means for absorbing a secondary collision energy of an occupant at the time of a vehicle collision, wherein a distance to an object existing in front of the vehicle is detected. Distance detecting means; speed detecting means for detecting a traveling speed of the host vehicle; energy absorbing amount adjusting means for changing the amount of the secondary collision energy absorbed by the collision energy absorbing means; the distance detecting means and the speed detection Collision prediction means for predicting a collision between the own vehicle and the object from a detection result of the means; and when the collision prediction means predicts a collision between the own vehicle and the object, the energy absorption amount adjusting means before collision. And a drive control means for controlling the driving of the shock-absorbing steering column device.