JP2004017664A - Brake for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake for a vehicle wherein the vehicle is braked by different approach from conventional braking of the vehicle by friction of a tire and a road surface. <P>SOLUTION: This braking device l0 for the vehicle to apply braking force to the vehicle by gas pressure is constituted of a braking surface 11b to generate the braking force by contact with the road surface, a braking surface moving means 11 to make the braking surface 11b contact with the road surface by the gas pressure at the time of braking and a gas pressure generating means 13 to supply the gas pressure to the braking surface moving means 11. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicular braking device that applies a braking force to a vehicle.
[0002]
[Prior art]
Conventional brakes are based on the principle that the brake pedal is depressed and the kinetic energy of the vehicle is consumed by the friction between the tire and the road surface by the drum type or disk type brake, and the driver actually stops. When the vehicle is to be stopped, the function of the brake does not mean that the vehicle can be stopped immediately. There is a certain distance (hereinafter referred to as "braking distance") from the time when the driver operates the brake and the brake starts to work until the vehicle completely stops.
It is desirable that the braking distance be short. Shortening of the braking distance is achieved by increasing the contact area where the tire contacts the road surface. It is also achieved by increasing the coefficient of friction between the tire and the road. Specifically, when the tires are widened, the contact area increases, so that the braking distance can be shortened. Further, when the rubber compound of the tire is made soft, the coefficient of friction between the tire and the road surface increases, so that the braking distance can be shortened.
[0003]
[Problems to be solved by the invention]
However, if the tire is widened to increase the ground contact area, or if the rubber compound of the tire is softened to increase the friction coefficient, the braking distance can be shortened, but the fuel efficiency of the vehicle is deteriorated. Further, since the vehicle is normally in contact with the road surface with four tires, there is a limit in increasing the contact area. Also, there is a limit in increasing the coefficient of friction between the tire and the road surface. That is, there is a point to be considered in shortening the braking distance of the vehicle.
[0004]
Therefore, an object of the present invention is to provide a vehicle braking device that can brake a vehicle by an approach different from the conventional braking of a vehicle due to friction between a tire and a road surface.
[0005]
The present invention is configured to solve the above problems, and is a vehicle braking device that applies a braking force to a vehicle by gas pressure, wherein the vehicle braking device reduces a braking force by contact with a road surface. A braking surface to be generated, braking surface moving means for bringing the braking surface into contact with a road surface by the gas pressure at the time of braking, and gas pressure generating means for supplying the gas pressure to the braking surface moving means. And
[0006]
According to the present invention, when the braking surface moving unit supplied with the gas pressure by the gas pressure generating unit moves the braking surface, the braking surface comes into contact with the road surface to generate a braking force. That is, braking different from conventional braking by friction between the tire and the road surface is realized.
[0007]
The braking force in the present invention may be generated in combination with a braking force generated by a conventional braking device or braking method, or may be generated alone. Further, the braking force may be generated by the driver's intention, or the braking force may be generated regardless of the driver's intention. In the present invention, the size and shape of the braking surface can be set arbitrarily. Which part of the expansion means is to be rubbed against the road surface can also be arbitrarily set.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a vehicular braking device according to the present invention will be described in detail with reference to the drawings.
In the drawings referred to, FIG. 1A is a side view of a vehicle equipped with a vehicle braking device according to the present embodiment, FIG. 1B is a cross-sectional view of an airbag housed in a module case, and FIG. It is a side view of the vehicle in which the bag is deployed. FIG. 3 is a block diagram of the vehicle braking device according to the present embodiment.
[0009]
The vehicle braking device 10 of the present embodiment shown in FIG. 1 is a device for deploying the airbag 11 to brake the vehicle, and deploys from the underbody side (lower surface side) of the vehicle toward the road surface (road surface side). An airbag 11, a module case 12 for accommodating the airbag 11, an inflator 13 for supplying a high-pressure gas to the airbag 11 to deploy the airbag 11, and a high-pressure gas generation signal to the inflator 13. And a control unit 14 (see FIG. 3) for transmitting. Here, the airbag 11 corresponds to “braking surface moving means”, and the inflator 13 corresponds to “gas pressure generating means”.
[0010]
2A is a perspective view of the airbag according to the present embodiment before deployment, and FIG. 2B is a perspective view of the airbag of FIG. 2A after deployment.
The airbag 11 is formed in a bag shape mainly from nylon or the like which has high friction resistance and excellent impact resistance, and has a plurality of high-pressure gas introduction holes 11a. As shown in FIG. 2A, the airbag 11 is normally folded and accommodated in the module case 12, but when the vehicle is braked, the airbag 11 is deployed as shown in FIG. The bottom surface 11b of the wheel 11 rubs against the road surface. Therefore, the airbag 11 is attached to the vehicle with such a strength that it does not fall off due to friction with the road surface.
[0011]
As shown in FIG. 1C, the size of the airbag 11 needs to be at least such that it can be deployed from the underbody side of the vehicle and the bottom surface 11b can contact the road surface. Also, the width is only to fit between the left and right tires and the length is not to exceed the length of the vehicle so that the deployment is not disturbed by the tires. The bottom surface 11b corresponds to a “braking surface” in the claims.
[0012]
As shown in FIG. 1B, the module case 12 has a rectangular box shape, and accommodates the folded airbag 11 and the inflator 13 therein.
The module case 12 is provided near the center of the underbody of the vehicle (see FIG. 1A).
The lower surface of the module case 12 facing the road surface has an opening, and the opening is covered by a tear line 12a. The tear line 12a is formed to be thin with a foamed resin or the like, and when the airbag 11 is deployed, the tear line 12a is broken and the airbag 11 is deployed toward the road surface.
[0013]
The inflator 13 is a high-pressure gas generator having a high-pressure gas supply pipe 13a that communicates with the high-pressure gas introduction hole 11a of the airbag 11 in order to supply the high-pressure gas to the airbag 11. A cylinder provided with a high-pressure gas generating agent that generates an inert high-pressure gas is used alone or in combination. In an airbag for an SRS (Supplemental Restriction System), the amount of explosive or the like is suppressed in consideration of an impact to an occupant or the like, and the airbag is deployed in approximately 30 ms (millisecond). In the vehicle braking device 10 according to the above, such consideration is not necessary, so that the explosive provided for the inflator 13 can be increased or the deployment time can be reduced to 5 ms or less by using high-pressure compressed air.
The inflator 13 is housed in the module case 12 together with the airbag 11 and provided on an underbody of the vehicle.
The inflator 13 receives a high-pressure gas generation signal from a control device 14 described later, and supplies the high-pressure gas into the airbag 11 through the high-pressure gas supply pipe 13a. Here, the high-pressure gas used includes, for example, nitrogen gas and compressed air.
[0014]
As shown in FIG. 3, the control device 14 is connected to vehicle collision detection means 14a for detecting a vehicle collision, such as a semiconductor acceleration sensor, and detects a vehicle collision. Further, the control device 14 controls the transmission of the high-pressure gas generation signal for deploying the airbag 11 to the inflator 13 when the vehicle collision detection unit 14a detects the collision of the vehicle. The ON signal in FIG. 3 corresponds to an ON signal in FIG. 5 described later, and is, for example, a signal from a switch that can be turned ON (operation instruction) by the driver's will.
[0015]
Hereinafter, the operation of the vehicle braking device 10 according to the present embodiment will be described.
First, as shown in FIG. 3, when the vehicle collides, the vehicle collision detection means 14 a detects the collision in the control device 14, and the control device 14 transmits a high-pressure gas generation signal to the inflator 13.
Then, the inflator 13 catches the high-pressure gas generation signal and blows out the high-pressure gas into the airbag 11 through the high-pressure gas supply pipe 13a.
The airbag 11 supplied with the high-pressure gas starts to inflate, breaks the tear line 12a of the module case 12, jumps out from the underbody side of the vehicle toward the road surface, and as shown in FIG. Deploy to contact the road surface near the center of gravity.
[0016]
According to the above, the following effects can be obtained in the present embodiment.
By deploying the airbag 11 so as to be in contact with the road surface, the total contact area of the vehicle is reduced to the contact area that contacts the road surface with the four tires, and the contact area of the bottom surface 11b of the airbag 11 that contacts the road surface. Widen to add. Therefore, the frictional force with the road surface can be increased, and the braking distance of the vehicle can be shortened. Thereby, collision can be prevented beforehand. Even if a collision occurs, the kinetic energy due to the collision can be reduced, the impact applied to the occupant can be reduced, and a secondary collision that occurs when the vehicle is flipped is also effective. Such prevention of collision and reduction of kinetic energy are advantageous not only for the vehicle but also for the other party.
[0017]
When the airbag 11 is deployed at the center of gravity of the vehicle as in the present embodiment (placed at the center), the vehicle may be spun. When the vehicle spins, the collision energy can be dispersed by rotation.
Further, although the airbag 11 is normally housed compactly, it is inflated with high gas pressure during vehicle braking, so that the installation space for the vehicle braking device 10 can be reduced. Therefore, a large cabin space or a large crushable zone can be obtained.
[0018]
Further, the present invention can be implemented as follows.
That is, in the above-described embodiment, the bottom surface 11b of the airbag 11, which is a braking surface or a friction surface, is not particularly worked, but a configuration in which a spike is provided or a configuration having adhesiveness may be used. By providing the spikes, the braking distance can be reduced even on a low friction road surface such as a snowy road or an ice burn. In addition, for example, when the bottom surface 11b comes into contact with the road surface, the braking distance can be further reduced by adopting a configuration having an adhesive property such as peeling off the skin and exposing an adhesive substance. Here, a silicone resin or the like can be used as the sticky substance.
[0019]
In the above-described embodiment, the braking surface is provided directly on the airbag 11 serving as the inflating means. However, the braking surface may be provided indirectly on the inflating means. For example, a configuration in which a rubber plate is bonded to an airbag serving as an inflation means can be adopted.
[0020]
In the above-described embodiment, as shown in FIGS. 4A and 4C, the module case 12 is provided near the center of the underbody of the vehicle (center placement). However, the present invention is not limited to this. Instead, for example, as shown in FIGS. 4A and 4B, it can be provided near the front such as under the engine (front mounting). With this configuration, the airbag 11 is deployed in the vicinity of the front, so that the contact force increases due to the movement of the load at the time of deceleration, which is effective. Dive is held down, and it can be prevented from getting into the other car.
Further, for example, as shown in FIGS. 4A and 4D, the module case 12 can be configured to be provided near the rear such as under the trunk (rear place). With such a configuration, the steering can be relatively easily performed even when the airbag 11 is deployed.
Further, the storage space for the airbag 11 and the module case 12 may be provided vertically between the engine room and the passenger compartment, for example, in the width direction of the vehicle.
[0021]
In the above-described embodiment, the control device 14 includes the vehicle collision detecting means 14a. However, the control device 14 does not include the vehicle collision detecting means 14a, or additionally includes the distance to the obstacle ahead and the distance to detect the vehicle speed. -It is good also as a structure which has a speed detection means. With this configuration, for example, when traveling at a certain speed or higher, if there is an obstacle in a forward direction within a certain distance, this is detected and the airbag 11 is controlled to deploy. can do. Therefore, even if the driver is sick or careless in the forward direction, it is possible to prevent the vehicle from colliding with an obstacle ahead as much as possible.
Similarly, the control device 14 may be configured to include a heart rate measuring unit for measuring the driver's heart rate. With this configuration, the state of the driver can be detected, and the control device 14 can control the airbag 11 to deploy. Of course, the airbag 11 may be controlled so that the airbag 11 is deployed by measuring and detecting not only the heart rate but also the blood pressure, body temperature, brain waves, pupil shape, and the like.
Furthermore, the control device 14 may perform control such as partially deploying the airbag 11 or adjusting the deployment pressure according to the state of collision. By doing so, the gravity control (G control) of the occupant becomes possible.
[0022]
Further, the brake lamp may be turned on when the airbag 11 is inflated and deployed. With this configuration, the driver of the following vehicle can know that the braking force is acting on the vehicle by turning on the brake lamp. That is, in the vehicle, a brake switch is provided on the brake pedal to detect the operation / non-operation of the brake, and the brake lamp is turned on when the brake is operated. However, the deployment of the airbag may be performed independently of the depression of the brake pedal, and if the brake lamp is not lit in such a deployment, the braking force acts on the vehicle even though the brake lamp is not lit. As a result, the vehicle decelerates, which is inconvenient. Therefore, it is preferable to turn on the brake lamp.
[0023]
FIG. 5 shows an example of the operation logic. This operation logic operates when any of the conditions (1) to (6) is satisfied.
[0024]
In the configuration of the present invention, the control device 14 controls the airbag 11 to be deployed when the vehicle enters the sea, lake, river, or the like, as shown in FIG. (Buoyancy device). Conventionally, as shown in FIG. 6 (a), there is no vehicle that gives buoyancy to the vehicle. However, the airbag 11 deployed at the time of entering water can give buoyancy to the vehicle as a float, and the inundation speed is reduced. You. During this time, the occupants can escape and rescue themselves.
[0025]
As described above, the present invention has been described as having the functions of braking, buoyancy assistance, and buoyancy generation. However, the effect obtained by deploying the airbag 14 from the underbody side of the vehicle toward the road surface is limited to this. Instead, for example, it has a function as a maintenance (air) jack at the time of tire replacement and a function as an escape means when the vehicle is stuck.
[0026]
In addition, it goes without saying that the size, shape, and material of the airbag, the number of high-pressure gas introduction holes of the airbag, the number of high-pressure gas supply pipes of the inflator, and the deployment direction can be appropriately changed.
In the above-described embodiment, the airbag 11 is deployed straight in the road surface direction from the underbody side of the vehicle. However, it is not always necessary to deploy the airbag 11 such that the braking surface of the airbag reaches the road surface at the shortest distance. For example, the airbag may be deployed diagonally forward of the vehicle. In addition, even if the airbag illustrated in FIG. 1 is partitioned into a plurality of rooms (for example, the airbag 11 is partitioned in the front-rear direction of the vehicle), and even if a part of the airbag 11 is It is also possible to make it not to reach other parts of the airbag 11. Further, by controlling the gas pressure, the airbag 11 can be deployed and stored, and can be used repeatedly depending on the situation.
[0027]
Next, a situation result when a vehicle equipped with the vehicle braking device 10 according to the embodiment of the present invention collides will be described with reference to FIG.
FIG. 7 is an explanatory diagram illustrating a relationship between time and a vehicle situation when a vehicle equipped with the vehicle braking device according to the embodiment of the present invention collides.
[0028]
First, in this example, a collision state when a vehicle traveling at a certain speed collides head-on against a wall surface was examined. An SRS acceleration sensor (G sensor) is used as the vehicle collision detection means 14a.
As shown in FIG. 7, the vehicle collides with the wall surface in 0 ms (millisecond) (the instant of the collision is 0 ms). After a lapse of 5 ms from the collision, the acceleration sensor of the control device 14 detects the collision and transmits a high-pressure gas generation signal to the inflator 13. As a result, the airbag 11 of the vehicle braking device 10 starts to be deployed and ends after 10 ms has elapsed. The airbag for SRS in the passenger compartment is deployed 30 ms after the collision, and the vehicle can be stopped 80 ms after the collision. On the other hand, in the conventional vehicle without the vehicle braking device 10, the vehicle could stop 100 ms after the collision.
Therefore, it has been found that the vehicle equipped with the vehicle braking device 10 can be stopped 20 ms earlier than the conventional vehicle due to the frictional force between the airbag 11 and the road surface.
[0029]
The gravitational acceleration generated in the vehicle and the occupant at the time of a frontal collision will be described with reference to FIG.
FIG. 8A is a graph showing the relationship between the gravitational acceleration generated in the vehicle and the occupant when a conventional vehicle collides head-on, and time, and FIG. 8B shows the vehicle equipped with the vehicle braking device according to the present invention. 5 is a graph showing the relationship between the gravitational acceleration generated in the vehicle and the occupant when the vehicle has a frontal collision and the time.
[0030]
As shown in FIG. 8A, the conventional vehicle requires a cushion stroke and time because most of the kinetic energy is absorbed by the deformation of the vehicle body, and the gravitational acceleration generated in the vehicle gradually increases after the collision. , Record the highest value, then suddenly decrease and stop. In addition, the gravitational acceleration generated in the occupant begins to appear some time after the collision, draws a parabolic waveform that eventually reaches a peak, and then disappears.
[0031]
On the other hand, as shown in FIG. 8B, the gravitational acceleration generated in the vehicle equipped with the vehicle braking device 10 rapidly increases slightly after the collision in which the braking airbag 11 is deployed, and the cushion stroke and Time shortens and stops. The kinetic energy received by the conventional vehicle and the vehicle equipped with the vehicle braking device 10 due to the collision are the same, but the energy is consumed by the braking by the vehicle braking device 10, that is, the friction between the braking surface and the road surface. The braking distance is reduced.
[0032]
Further, the gravitational acceleration generated in the occupant starts appearing some time after the collision, reaches a peak earlier than in the case of the conventional vehicle, and draws a parabolic waveform that disappears earlier. At this time, the gravitational acceleration generated by the occupant is smaller than the gravitational acceleration generated by the occupant of the conventional vehicle because the kinetic energy received by the collision is consumed by the friction between the airbag 11 and the road surface. That is, the peak decreases and the gravitational acceleration is consumed more quickly.
Therefore, it was found that the gravitational acceleration generated in the occupant, that is, the damage to the occupant can be reduced in the vehicle equipped with the vehicle braking device 10.
[0033]
Incidentally, if it is attempted to obtain the braking force (the braking force of the normal brake + the braking force of the vehicle braking device 10) as in the present embodiment by the conventional braking only with the frictional force between the tire and the road surface, the tire becomes wider. However, the compound must be soft, and the suspension and hydraulic circuit must be correspondingly strong, which leads to an increase in rolling resistance and an increase in vehicle weight, which significantly reduces fuel consumption. According to the vehicular braking device 10 of the present embodiment, the increase in vehicle weight can be suppressed low while the rolling resistance remains unchanged. As a result, it is possible to obtain a favorable braking force that cannot be obtained conventionally, without adversely affecting the fuel efficiency. In addition, fuel efficiency is directly linked to environmental issues such as CO ₂ emissions.
[0034]
【The invention's effect】
According to the present invention, the braking surface is moved by the braking surface moving unit supplied with the gas pressure by the gas pressure generating unit, so that the braking surface comes into contact with the road surface and the ground contact area with the road surface can be increased. Therefore, the braking distance of the vehicle can be reduced. Further, braking different from the conventional one can be performed.
[Brief description of the drawings]
1A is a side view of a vehicle equipped with a vehicle braking device according to an embodiment, FIG. 1B is a cross-sectional view of an airbag housed in a module case, and FIG. FIG. 1 is a side view of a running vehicle.
2A is a perspective view of the airbag according to the present embodiment before deployment, and FIG. 2B is a perspective view of the airbag of FIG.
FIG. 3 is a block diagram of the vehicle braking device according to the embodiment;
4A is a side view showing each deployment location of the airbag according to the present embodiment, FIG. 4B is a top view of a front installation, FIG. 4C is a top view of a center installation, and FIG. It is a top view of rear installation.
FIG. 5 is a control logic diagram of deployment (operation) of the airbag.
FIG. 6 (a) is an explanatory diagram showing a state when a conventional vehicle enters water, and FIG. 6 (b) is an explanatory diagram showing a state when an airbag according to the present invention is deployed when entering water.
FIG. 7 is an explanatory diagram showing a relationship between time and a vehicle situation when a vehicle equipped with the vehicle braking device according to the present invention collides.
FIG. 8A is a graph showing the relationship between time and gravitational acceleration generated in a vehicle and an occupant when a conventional vehicle collides head-on, and FIG. 5 is a graph showing the relationship between the gravitational acceleration generated on the vehicle and the occupant when the mounted vehicle makes a head-on collision and time.
[Explanation of symbols]
Reference Signs List 10 vehicle braking device 11 airbag 11a high-pressure gas introduction hole 11b bottom surface 12 module case 12a tear line 13 inflator 13a high-pressure gas supply pipe 14 control device 14a vehicle collision detection means

Claims (1)

A vehicle braking device for applying a braking force to a vehicle by gas pressure,
The vehicle braking device includes: a braking surface that generates a braking force by contact with a road surface;
Braking surface moving means for bringing the braking surface into contact with a road surface by the gas pressure during braking,
Gas pressure generating means for supplying the gas pressure to the braking surface moving means,
A vehicle braking device comprising:

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