JPH0714943Y2 - Vehicle collision prevention device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention projects a laser beam from a following vehicle toward a preceding vehicle, receives reflected light from the preceding vehicle by the following vehicle, and measures the distance to the preceding vehicle. The present invention relates to an improvement of a vehicle rear-end collision preventive device for detecting a vehicle-to-vehicle distance and thereby preventing a rear-end collision of a vehicle.

[Prior Art] This type of vehicle rear-end collision prevention device is already known.

An example is shown in FIGS. 1 and 2, and in FIG. 1, a light sending and receiving means (hereinafter referred to as “laser radar head”) 1 is provided in front of the preceding vehicle A-1 and the following vehicle A-2. A reflector (light reflecting plate) 2 is attached to the rear part. The laser light (shown by the solid arrow) from the laser radar head 1 of the following vehicle A-2 is reflected by the reflector 2 of the preceding vehicle A-1, and the reflected light (shown by the dotted arrow) is received by the laser radar head 1. Then, the distance to the vehicle in front is obtained from the round-trip time of the laser light, and the inter-vehicle distance L is detected by this.

FIG. 2 shows the configuration of the laser radar head, 3 is a light transmitter, 4 is a light receiver, and the light transmitter 3 includes a light transmitting lens 5, a laser diode (L / D) 6, and an L / D driving circuit 7. , The trigger circuit 8, and the light receiver 4 is composed of the light receiving lens 9, the light receiving element 10, and the amplifier 11, and the outputs from the light transmitter 3 and the light receiver 4 are input to the distance detection circuit 12 to measure the distance to the vehicle ahead. Is obtained from the round trip time of the laser light, and the inter-vehicle distance L is known.
These are conventionally known.

[Problems to be Solved by the Invention] FIG. 3 shows an example in which a device for detecting an inter-vehicle distance according to the above-described mode is mounted on a truck, and a laser radar is provided in the front part of the truck A (immediately above the front frame). The head 1 is attached, and an information processing device 13, a display switch box 14, a distance display unit 15, and a monitor output box 16 are provided in the driver's cab.

When the switch 14 is turned on, the laser light from the laser radar head 1 is projected toward the preceding vehicle, the reflected light is received by the laser radar head 1, and the reflected light is input to the information processing device 13 to determine the distance to the vehicle ahead. The inter-vehicle distance is displayed on the cover unit 15 based on the round trip time. The driver drives the truck A with a required inter-vehicle distance based on the inter-vehicle distance displayed on the distance display unit 15.

By the way, in an automobile, especially in a truck, the inclination angle of the driver's cab changes between when the vehicle is loaded and when the vehicle is empty, and the optical axis angle of the laser beam projected from the laser radar head also changes accordingly.

The state is shown in Fig. 4, and the condition is the empty product difference (cargo).
0.75 °, laser light angle 3.4 °, pitching Σ0.75 ° due to unevenness of the ground, laser radar head 1 mounting height
h1 is 0.85 m, reflector 2a mounting height for trucks is h2 1.5 m, reflector 2b mounting height for passenger cars is h3
Is 0.5m.

L1 is not detected when the distance between vehicles is 10 m or less, and L2 when the distance is up to 30 m
Includes detection by body etc., L3 is detected by reflector when 30m or more and 80m. In the cargo cargo, the laser radar head 1 is angled upward to 0.4 °, and in the empty cargo, the laser radar head 1 is angled downward to 0.35 °.

In the figure, a1 is the optical axis of the laser beam in the empty cargo and is 0.35 ° downward, and a2 is the upper limit of the empty cargo and is upward from the optical axis a1.
7 °, a3 is the upper limit of empty cargo pitching 0.38 °, a4 is the lower limit of empty cargo 1.7 ° downward from the optical axis a1, a5 is the lower limit of empty cargo pitching 0.38 °, b1 is the optical axis of the laser light in the cargo cargo, upward 0.4 °, b4 is the lower limit of cargo cargo 1.7 ° downward from the optical axis b1, and b5 is the lower limit of cargo cargo pitching 0.38 °.

By the way, since the conventional device does not have an appropriate means for changing the light angle of the laser radar head depending on whether the vehicle is loaded or emptied, it is not possible to accurately project the laser light on the reflector according to the loaded or emptied vehicle. However, it is not always satisfactory when driving with a sufficient inter-vehicle distance such as when driving on a highway. Especially, the adjustment could not be easily performed from the front of the vehicle.

That is, as disclosed in Japanese Patent Laid-Open No. 60-88381, the distance between vehicles is measured and the distance at which an alarm is issued is changed, and its optical axis cannot be changed. Further, Japanese Patent Publication No. 59-31814 discloses a reflective photoelectric switch capable of adjusting the optical axis of a light projecting element. However,
Such a known technique is to change the optical axis of each of the light emitting and receiving units angularly in the case. When this is applied to a vehicle rear-end collision prevention device, the optical axis can be adjusted accurately. I can't.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to easily fine-adjust the optical axis of laser light projected from the light transmitting and receiving means (laser radar head) from the front of the vehicle. A vehicle rear-end collision prevention device is provided.

[Means for Solving the Problems] A vehicle rear-end collision prevention device of the present invention is directed from a laser radar head having a light-transmitting means and a light-receiving means mounted on a front portion of a following vehicle toward a reflector mounted on a rear portion of a preceding vehicle. The laser beam is projected, the reflected light reflected by the reflector of the preceding vehicle is received by the laser head of the following vehicle, the distance to the vehicle in front is calculated from the round trip time of the laser beam, and an alarm is issued when the distance is less than the safe inter-vehicle distance. In a vehicle rear-end collision prevention device for preventing rear-end collision, a pair of links (24a), (24b) arranged so that a side surface of a laser radar head (20) having the light-transmitting means and the light-receiving means has a V shape is horizontal. A bracket (2) connected to the support plate (22) and provided on the horizontal support plate (22).
3) and a spring receiving plate (21) provided on the laser radar head (20) have support springs (28) whose both ends are in contact with each other, and the laser radar head (28) is expanded or contracted in accordance with expansion and contraction of the support spring (28). 20) so that the optical axis of the link (24a), (24b) is changed by changing the angle of the optical axis of the link (24a), (24b) and the spring receiving plate (21). The adjusting screw (25) extends through the hole
And the threaded portion of the adjusting screw (25) is the spring receiving plate (2
1) It is screwed with the nut (27) that protrudes.

[Advantage of the Invention] When the laser radar head 20 is moved to the right in FIG. 5 by turning the adjusting screw 25 from the front of the vehicle by the spring force of the support spring 28, the links 24a, 24b and the laser radar head 20 are pivotally attached. Move to point (b), (b), laser radar head
20 tilts forward and the laser optical axis becomes (b)-(b). When the adjusting screw 25 is turned in the opposite direction to compress the support spring 28 to move the laser radar head 20 leftward in FIG. 5, the pivot points of the links 24a, 24b and the laser radar head 20 are set. After moving to (a) and (a), the laser radar head 20 tilts backward and the laser optical axis becomes (a)-(a). At this time, it is unstable if the laser head 20 is supported only by the links 24a and 24b, but it is stable by the support spring 28.
Can be located. Further, the spring seat 21 and the bracket 23 are angularly displaced along with the change of the optical axis, but the support spring 28 can also absorb the displacement. This makes it possible to set the laser optical axis according to when the vehicle is empty and when the cargo is loaded. The C-shaped links position the balance in the vertical direction, and the balance in the front-back direction is given by the force of the spring to determine the position based on the overall balance. The spring force in the front-rear direction should have a sufficiently high spring constant so that the spring force does not easily bend when the vehicle is accelerated.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 5, the laser radar head 20 is supported on a horizontal support plate 22 fixed to the vehicle body by a pair of links 24a and 24b arranged in a V shape. When the laser radar head 20 is moved to the left in FIG. 5, the pivot points of the laser radar head 20 and the links 24a and 24b move to (a) and (a), and the laser optical axis becomes (a)- (I)
Becomes Conversely, when the laser radar head 20 is moved to the right in FIG. 5, the laser radar head 20 and each link 24
The pivot points of a and 24b move to (b) and (b), and become the laser optical axis (b)-(b).

An adjusting screw 25 and a support spring 28 are used to move the laser radar head 20 leftward or rightward in FIG. A bracket that extends vertically to the horizontal support plate 22
23 is attached by welding or the like, and the laser radar head 20 is provided with a spring bearing plate 21 provided on the left side of the longitudinal center of the drawing in the direction intersecting the moving direction of the laser radar head 20 by welding or the like. Installed by. Adjusting screw 25 is bracket 23 with its head outwards.
A nut 27 is attached to the threaded portion that extends through the long hole formed in the spring receiving plate 21 and the hole formed in the spring receiving plate 21 and projects from the spring receiving plate 21.
Are screwed together. Head of adjusting screw 25 and bracket 23
A medium-hard rubber 26 is interposed between and. The long hole formed in the bracket 23 has a size that allows the laser radar head 20 to tilt forward and backward. A support spring 28, which is a compression spring, is interposed between the bracket 23 and the spring receiving plate 21 to constantly press the laser radar head 20 to the right in FIG.

Now, a direction in which the nut 27 is prevented from rotating with one hand and, for example, a screwdriver is engaged with a groove formed in the head of the adjusting screw 25 so that the screw tip portion of the adjusting screw 25 is pulled toward the spring bearing plate 21. When the laser radar head 20 is rotated to the
Is moved to the right in FIG. 5 by the links 24a, 2
The pivot point between 4b and the laser radar head 20 is (b), (b)
Then, the laser radar head 20 tilts forward and the laser optical axis becomes (b)-(b). On the contrary, when the adjusting screw 25 is rotated in the direction in which the tip of the screw projects further from the spring receiving plate 21, the laser radar head 20 compresses the support spring 28 and moves it to the left in FIG. The pivot points of 24b and the laser radar head 20 are (a) and (a).

Therefore, in the cargo cargo, under the conditions shown in FIG. 4, the adjustment screw 25 is adjusted so that the optical axis of the laser radar light is inclined forward by 0.4 °, and in the empty car cargo, the optical axis of the laser light is inclined backward by 0.35 °. Adjustment screw 25 as described above. Of course, if one of the empty and loaded states is adjusted, the other one is automatically set.

To adjust the horizontal angle of the laser radar head 20, the horizontal support plate 22 may be fixed at that position by rotating the horizontal support plate 22 at an appropriate angle with the bracket 23 side of the horizontal support plate 22 as a rotation fulcrum.

[Effects of the Invention] As described above, the present invention has the following excellent effects.

(I) Since the laser radar head itself can be tilted forward or backward by the link by turning the adjustment screw provided on the front surface to change the optical axis of the laser, the angle of the optical axis is adjusted depending on when the vehicle is empty or loaded. Alternatively, it can be fine-tuned.

(Ii) Since the adjusting screw is provided on the front surface, the adjusting work can be performed easily and accurately.

(Iii) Stable positioning of the laser head can be performed even while the vehicle is traveling by the combination of the spring and the adjusting screw.

(Iv) If a screen or the like is provided in advance, it is possible to know the position of the optical axis by looking at the screen while adjusting the adjusting screw from the front.

(V) As a result, an easy and proper laser optical axis can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a mode of detecting an inter-vehicle distance by laser radar light, FIG. 2 is a configuration diagram of a laser radar head, and FIG.
FIG. 4 is a view showing a state in which a vehicle is equipped with a rear-end collision prevention device using a laser beam, FIG. 4 is a view showing an angle adjustment mode of a laser radar head during loading and empty, and FIG. 5 is a view of the present invention. It is a longitudinal cross-sectional view showing an angle adjusting means of the laser radar head according to the embodiment. 20 ... Laser radar head, 24a, 24b ... Link, 25 ...
… Adjusting screw, 28 …… Support spring

Claims (1)

[Scope of utility model registration request] 1. A laser radar head having a light-transmitting means and a light-receiving means attached to a front portion of a following vehicle projects a laser beam toward a reflector attached to the rear portion of a preceding vehicle and is reflected by the reflector of the preceding vehicle. The reflected light is received by the laser head of the following vehicle and the distance to the vehicle in front is calculated from the round-trip time of the radar light. A pair of links (24) in which a side surface of a laser radar head (20) having an optical means and a light receiving means is arranged so as to have a V shape.
a) and (24b) are connected to the horizontal support plate (22), and are respectively attached to a bracket (23) provided on the horizontal support plate (22) and a spring bearing plate (21) provided on the laser radar head (20). It has a support spring (28) with which both ends abut, and the support spring (2
The optical axis of the laser radar head (20) is opened in the bracket (23) so that the angle of the optical axis changes according to the angle change of the links (24a) and (24b) according to the expansion and contraction of 8). The adjusting screw (25) extends through the long hole and the hole formed in the spring bearing plate (21), and the thread portion of the adjusting screw (25) projects from the spring bearing plate (21) in the nut (27). ) Is screwed together with a rear-end collision prevention device for a vehicle.