JP2008074288A - Occupant crash protection device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an occupant crash protection device for a vehicle capable of eliminating the necessity for discriminating a rolling direction and capable of determining the possibility of rolling using only one rolling determination condition expression. <P>SOLUTION: The occupant crash protection device for the vehicle is characterized in that it determines that there is possibility of rolling of the vehicle when a roll angle θ, a roll angular velocity ω and a lateral acceleration Gy of the vehicle satisfy the following formula (1); (ω×θ)+(ω×Gy)>C or ω×(θ+k×Gy)>C (k is positive coefficient and C is positive constant). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an occupant protection device for a vehicle including a curtain airbag or the like, and in particular, when an appropriate rollover determination condition is satisfied, it is determined that the vehicle may roll over and the rollover that activates the curtain airbag or the like is activated. The present invention relates to a vehicle occupant protection device including a determination device.

  In recent years, there has been an increasing demand for the safety of vehicles such as passenger cars. When a vehicle rolls over, the occupant not only crashes the windshield, etc. It is becoming common for a vehicle to be equipped with a curtain airbag as a standard feature that prevents the vehicle from colliding with the side wall or side window of the vehicle or jumping out of the vehicle. At this time, the curtain airbag needs to be operated only when an appropriate rollover determination condition that achieves the above-described purpose is met, and several proposals have been made for such rollover determination condition.

According to Patent Document 1, when the sum of the rotational energy and potential energy of the vehicle exceeds the maximum potential energy (rolling limit energy) that can be maintained without the vehicle rolling over, the vehicle may roll over. Is determined. That is, according to the vehicle rollover judging method taught in Patent Document 1, the roll angle θ, which is the inclination angle of the vehicle body when the axis passing through the center of gravity of the vehicle and extending in the longitudinal direction (front-rear direction) of the vehicle is the rotation center. And the roll angular velocity ω at which the vehicle rotates around the center of rotation, the following equation showing the rollover region in the first quadrant of FIG. 6 is established, and it is determined that the vehicle may roll over: The
ω> −p × θ + q (p and q are positive constants)
JP 2001-71844 A

However, in the above equation, the roll angular velocity ω and the roll angle θ are values having directions, and it should be determined that the vehicle may roll over only when the directions (polarity and sign) match. In fact, not only the above formula but also the following relational expression indicating the rollover region in the third quadrant of FIG.
ω <−p × θ−q (p and q are positive constants)
That is, according to the vehicle rollover determination method of Patent Document 1, it is necessary to determine two determination conditions (determination conditions based on two inequalities) for each rotation direction, that is, according to the rollover direction (considering the rollover direction). It is necessary to perform rollover determination, and the determination process becomes complicated.

  In addition, when the vehicle rolls over slowly (with ω kept small), when the vehicle is activated to roll over with the above two inequalities determined to roll over, the occupant's head If the vehicle has already approached the side wall or side window of the vehicle or protrudes outward from the side window, the curtain airbag will deploy (interfere) so that the passenger's head is pushed out of the vehicle. There can be.

  Furthermore, curtain airbags are generally deployed using an irreversible chemical reaction, and once deployed, they need to be replaced with new ones. From an economic point of view, it is highly desirable to avoid unnecessary deployment. At this time, for example, when another vehicle collides from the side to the vehicle in a stationary state, the curtain airbags on the side of the side collision are not deployed, but the curtain airbags on both sides of the side collided vehicle are not deployed. It is preferable from an economic viewpoint that only the bag is deployed and the opposite curtain airbag is not deployed. However, the roll angular velocity ω is usually calculated based on the lateral acceleration Gy, and when a very large lateral acceleration Gy is momentarily applied due to a side collision, a very large roll angular velocity ω may be detected instantaneously. is there. At this time, if it is determined that there is a possibility of rollover using the above two inequalities, the curtain airbags on both sides including the curtain bag that does not need to be deployed are deployed, resulting in economical waste. Therefore, in the case of a side collision, the occupant protection device determines that the rollover determination condition is not satisfied (so as not to deploy the curtain airbags on both sides), and uses a separately provided side collision determination device, It is preferable to control so that only the curtain airbag on the collision side is deployed and the curtain airbag on the opposite side is not deployed.

The vehicle occupant protection device according to the present invention is characterized in that when the roll angle θ, the roll angular velocity ω, and the lateral acceleration Gy of the vehicle satisfy the following expressions, it is determined that the vehicle may roll over. .
(Ω × θ) + k (ω × Gy)> C or ω × (θ + k × Gy)> C
(K is a positive coefficient, C is a positive constant)

  According to the vehicle occupant protection device of the present invention, the necessity of identifying the rollover direction can be eliminated, and the possibility of rollover can be determined using only one rollover determination conditional expression. Also, when the vehicle rolls over slowly or when a side collision occurs from the side, the curtain airbag or the like can be prevented from being activated.

  Embodiments of a vehicle occupant protection device according to the present invention will be described below with reference to the accompanying drawings. In the description of the embodiment, for easy understanding, terms representing directions (for example, “vertical direction”, “lateral direction”, “clockwise direction”, “counterclockwise direction”, etc.) are used as appropriate. This is for explanation and these terms do not limit the present invention.

  FIGS. 1A and 1B are schematic cross-sectional views of the vehicle V cut along a plane perpendicular to the traveling direction of the vehicle V. FIG. 1A is a schematic view of the vehicle V running on a road surface that is substantially flat. (B) corresponds to a state where the vehicle is traveling on a road surface inclined at a predetermined inclination angle. In FIG. 1A, the center of gravity G of the vehicle V is disposed at the center of the left and right wheels (tread length) T at a predetermined height (center of gravity height) Hv from the road surface. During traveling, the vehicle V receives Gy and Gz in the lateral and vertical accelerations. In addition, for example, when traveling on an inclined road surface as shown in FIG. 1B, a roll angular velocity ω with the axis extending through the center of gravity G and extending in the traveling direction (front-rear direction) is generated due to various factors. A roll angle θ that is an inclination angle of the vehicle V is generated between the vertical direction UD of the vehicle V and the vertical direction p. In particular, in the present specification, as indicated by arrows in FIGS. 1A and 1B, the rightward lateral acceleration Gy and the upward vertical acceleration Gz are set as positive directions, and similarly, a clockwise roll The angular velocity ω and the roll angle θ are defined as positive directions.

Embodiment 1 FIG.
FIG. 2 is a block diagram showing an occupant protection device 1 for the vehicle V according to the first embodiment of the present invention. As shown in FIG. 2, the occupant protection device 1 roughly includes a roll angular velocity sensor 10 that detects a roll angular velocity ω around the rotation center (center of gravity G), and a lateral acceleration that detects a lateral acceleration Gy of the vehicle V. A sensor 20 and a roll angle calculation unit 40 that calculates the roll angle θ of the vehicle V by time-integrating the roll angular velocity ω are provided. Whether the occupant protection device 1 satisfies the rollover determination condition (described in detail below) based on the roll angle θ, the roll angular velocity ω, and the lateral acceleration Gy, that is, whether the vehicle V may roll over. The rollover occurrence determination unit 50 that determines whether or not, and if it is determined that the vehicle is likely to roll over, the curtain airbag is activated in response to an input signal from the rollover occurrence determination unit 50 A protection device activation unit 60 to be activated.
Similarly, as shown in FIG. 2, it is preferable to appropriately provide filters 12 and 22 for removing high-frequency noise and offset errors that can be included in the output signals of the roll angular velocity sensor 10 and the lateral acceleration sensor 20.

a) ω-θ rollover determination map Generally, when the vehicle has a roll angle θ in the clockwise direction (positive value) in FIG. 1, the vehicle has a roll angular velocity ω in the counterclockwise direction (negative value). In some cases, the roll does not roll over, and there is a possibility of rollover when the roll angle θ and the roll angular velocity ω are in the same direction. At this time, if the roll angular velocity ω is sufficiently small even if the roll angle θ is large, or if the roll angle θ is sufficiently small even if the roll angular velocity ω is large, the possibility of vehicle rollover is small. Then, when the roll angle θ and the roll angular velocity ω are changed as parameters and whether or not the actual vehicle V rolls over is confirmed by an experiment, in the shaded region of the ω-θ rollover determination map shown in FIG. Was confirmed to roll over. Then, it has been found that the shaded area of the ω-θ rollover determination map of FIG. 3 is approximated by the following inequality.
ω × θ> c ₁ (c ₁ is a positive constant) (1)
As described above, when the roll angle θ and the roll angular velocity ω have the same polarity, the possibility of rollover occurs. In other words, the rollover possibility occurs because the value of (ω × θ) is at least a positive value. At the time.

b) ω-Gy rollover determination map Similarly, when the vehicle has a roll angular velocity ω in the clockwise direction (positive value) in FIG. 1, the vehicle has a lateral acceleration Gy in the counterclockwise direction (negative value). If the roll angular velocity ω and the lateral acceleration Gy have the same polarity, there is a possibility of rollover. At this time, if the roll angular velocity ω is sufficiently small even if the lateral acceleration Gy is large, or if the lateral acceleration Gy is sufficiently small even if the roll angular velocity ω is large, the possibility of vehicle rollover is small. When the roll angular velocity ω and the lateral acceleration Gy are varied as parameters, it has been experimentally confirmed that the vehicle rolls over in the shaded area of the ω-Gy rollover determination map shown in FIG. It was confirmed that the hatched area of the ω-Gy rollover determination map in FIG. 4 is approximated by the following inequality.
ω × Gy> c ₂ (c ₂ is a positive constant) (2)
Similar to the ω-θ rollover determination, the possibility of rollover occurs when the value of (ω × Gy) is at least a positive value.

Furthermore, according to the present invention, the rollover occurrence rate PR (Possibility of Roll-Over) is defined by the following equation.
PR = (ω × θ) + k × (ω × Gy) (k is a positive coefficient) (3)
Here, the rollover occurrence degree determination unit 50 of the present invention determines that the vehicle may rollover when the rollover occurrence degree PR exceeds a predetermined threshold value _Cth . That is, when the following expression is satisfied, the rollover occurrence determination unit 50 determines that the vehicle may rollover.
(Ω × θ) + k (ω × Gy)> C _th (4)
The region represented by this inequality (4) corresponds to the region indicated by the oblique lines in the rollover determination map (FIG. 5) by (ω × θ) − (ω × Gy), and (ω × θ) and (ω × Gy). Since the possibility of vehicle rollover occurs only when the value of) is positive, the possibility of rollover determination may be determined only in the first quadrant. That is, the rollover occurrence determination unit 50 according to the present invention uses the rollover determination conditional expression (4) to determine the rollover without considering the roll angle θ, the roll angular velocity ω, and the direction or polarity of the lateral acceleration Gy. Can be determined.
The positive constants in the above expression (3) and the rollover determination condition expression (4) that give the rollover occurrence rate PR are design set values that match the characteristics of the vehicle, and are (ω × θ) and (ω is set as the correlation coefficient × Gy), is a constant which can be defined rollover determination region with C _th.

  Further, when the vehicle V rolls over by gentle rotation, that is, when the roll angular velocity ω reaches a rollover with a small roll angular velocity ω, (ω × θ) and (ω × Gy) of the rollover judgment conditional expression (4) are small. It is not determined that the vehicle is likely to roll over. Therefore, the rollover occurrence determination unit 50 of the present invention suppresses the activation of the curtain airbag when it rolls over by gentle rotation, and the curtain airbag is deployed (interference) so that the head and neck of the occupant are pushed out of the vehicle. ) Can be avoided.

The rollover occurrence determination unit 50 of the present invention described above with reference to FIG.
As shown in the block diagram of FIG. 6, the rollover occurrence determination unit 50 calculates a product (ω × θ) in order to determine the rollover determination conditional expression (4). A second arithmetic unit 52 for obtaining (ω × Gy), a multiplier 53 for multiplying the product (ω × Gy) by a constant k, and an adder 54 for obtaining the sum of the product (ω × θ) and the product k (ω × Gy) , And the sum {(ω × θ) + k (ω × Gy)} and a predetermined threshold value C _th, and a comparator 55 that outputs an ON signal (High level signal) when the rollover determination condition is satisfied. .

Alternatively, the rollover occurrence determination unit 50 of the present invention may determine that there is a possibility of vehicle rollover when the next rollover determination condition is satisfied instead of the rollover determination conditional expression (4). Good.
ω × (θ + kGy)> C _th (5)
This rollover determination conditional expression (5) is obviously a modification of the previous rollover determination conditional expression (4), and is shown in the hatched area of the rollover determination map (FIG. 7) by ω− (θ + kGy). . Accordingly, the rollover occurrence degree determination unit 50 of the present invention may similarly determine the possibility of rollover determination in the hatched area (third quadrant is omitted) of the rollover determination map of FIG. 7, that is, roll angle θ, roll The possibility of rollover determination can be determined from the rollover determination conditional expression (5) without considering the angular velocity ω and the direction or polarity of the lateral acceleration Gy.

In order to determine the rollover determination conditional expression (5), the rollover occurrence determination unit 50 according to the present invention includes a multiplier 56 that multiplies Gy by a constant k as shown in the block diagram of FIG. An adder 57 for determining the value, a calculation unit 58 for calculating the product of ω and the sum (θ + kGy), and comparing the product {ω × (θ + kGy)} with a predetermined threshold value C _th , an ON signal ( The comparator 59 outputs a high level signal.

  The rollover occurrence determination unit 50 that determines the possibility of rollover determination using the rollover determination conditional expression (4) uses the two calculation units 51 and 52, whereas according to the rollover determination conditional expression (5), Since the rollover occurrence determination unit 50 determines the possibility of rollover determination using one arithmetic unit 58, the rollover occurrence determination unit 50 can use a more simplified configuration and is preferably smaller. Can be produced at low cost.

Embodiment 2. FIG.
A second embodiment of the occupant protection device for a vehicle V according to the present invention will be described below with reference to FIGS. 9 and 10. In the first embodiment, the influence of the vertical acceleration Gz on the vehicle rollover is not taken into account. However, in the second embodiment, a phenomenon in which one wheel is lifted depending on the vertical acceleration Gz (Tip-Up phenomenon). ) Occurs, the vehicle rollover is determined with higher accuracy by adding to the rollover determination condition that it is easier to roll over.

  The occupant protection device 2 for the vehicle V according to the second embodiment is generally configured using the same components as those of the occupant protection device 1 for the vehicle V according to the first embodiment except that the occupant protection device 1 has a safing determination unit. Therefore, the detailed description regarding the overlapping components is omitted. The same components as those in Embodiment 1 will be described using the same reference numerals.

As described above, the occupant protection device 2 for the vehicle V according to the second embodiment includes the upper and lower parts of the vehicle V in addition to the components of the occupant protection device 1 for the vehicle V according to the first embodiment, as shown in FIG. Only when the vertical acceleration sensor 30 for detecting the direction acceleration Gz, the safing determination unit 70, and the output signals of both the rollover occurrence degree determination unit 50 and the safing determination unit 70 are ON signals (High level signals). And an AND logic circuit unit 80 for outputting an ON signal (High level signal).
As shown in FIG. 9, it is preferable to appropriately provide a filter 32 for removing high-frequency noise, offset error, and the like that may be included in the output signal of the vertical acceleration sensor 30.

Generally, (the c ₃ positive constant) transverse absolute value c ₃ times the vertical acceleration Gz of the acceleration Gy when larger, the vehicle V has been confirmed that easily overturned. In view of this, the passenger protection device 2 for the vehicle V according to the second embodiment not only determines whether the rollover determination conditional expression (4) or (5) is satisfied, but further improves the determination accuracy. In the safing determination unit 70, it is determined whether or not the lateral acceleration Gy and the vertical acceleration Gz satisfy the following conditional expression.
| Gy |> c ₃ × Gz (6)

Specifically, the safing determination unit 70, as shown in FIG. 10, a multiplier 71 for multiplying the constant _{c 3} a vertical acceleration Gz, a product _{(c 3} × Gz) and the absolute value of the lateral acceleration Gy And a comparator that outputs an ON signal (High level signal) when it is determined that the lateral acceleration Gy is greater than the product (c ₃ × Gz).

Incidentally, the constant c ₃ uses the center of gravity height Hv and tread lengths T specification values of the vehicle V shown in FIG. 1, is defined as SSF value is an index showing a vehicle stability (Static Stability Factor, 2Hv / T ) However, when the following conditional expression is satisfied, it can be regarded as a Tip-Up phenomenon in which one wheel of the vehicle is lifted.
| Gy | / Gz> 2Hv / T (7)

  As described above, in the occupant protection device 2 for the vehicle V according to the second embodiment, the AND logic circuit unit 80 has both the output signals of the rollover occurrence determination unit 50 and the safing determination unit 70 as ON signals (High level signals). Only when it is, it is determined that there is a possibility of vehicle rollover, an activation signal is transmitted to the protection device activation unit 60, and the curtain airbag is deployed. That is, it is determined that the vehicle V may roll over when the Tip-Up phenomenon occurs depending on the lateral acceleration Gy and the vertical acceleration Gz in addition to the rollover determination condition of the first embodiment. Therefore, the turnover determination of the vehicle V can be performed with higher accuracy.

Embodiment 3 FIG.
A third embodiment of an occupant protection device for a vehicle V according to the present invention will be described below with reference to FIGS. The lateral acceleration Gy of the vehicle that occurs during normal road running is small. On the other hand, a large lateral acceleration is generated when the vehicle rolls over or at the time of a collision, and a very large lateral acceleration Gy is generated particularly in a side collision. It is desirable from an economical point of view to activate only a protection device such as a curtain airbag on the side that collided (collision side) at the time of a side collision, and not to operate a protection device on the side that did not collide (non-collision side). According to the occupant protection device 3 for the vehicle V according to the third embodiment, the value of k (ω × Gy), which is the second term of the rollover judgment conditional expression (4), at the time of a side collision in which a large lateral acceleration Gy occurs. It is possible to avoid the determination that the rollover occurs and the rollover occurs.

  The occupant protection device 3 for a vehicle V according to the third embodiment is roughly the same as the third embodiment except that the coefficient k included in the rollover judgment conditional expression is variable depending on the value of the lateral acceleration Gy. Since it is comprised using the component similar to the passenger | crew protection apparatus 1 and 2 of the vehicle V of 1 and 2, detailed description regarding the overlapping component is abbreviate | omitted. The same components as those in the first and second embodiments will be described using the same reference numerals.

  As described above, occupant protection device 3 for vehicle V according to Embodiment 3 selects coefficient k included in rollover determination conditional expression (4) or (5) depending on the value of lateral acceleration Gy. Designed as such. That is, the coefficient k of the rollover determination conditional expression of Embodiment 3 can be expressed as a function of the lateral acceleration Gy.

That is, the lateral acceleration Gy of the vehicle V generated in the normal traveling state is about 1 G (G is gravitational acceleration) at the time of a sharp curve traveling, and is compared with the lateral acceleration Gy when the rollover occurs. Small. In other words, when the lateral acceleration is small (depending on the characteristics of the filter, but less than 1 G, for example), the vehicle is unlikely to roll over, so that the rollover judgment conditional expression (4) or (5) is not satisfied ( The coefficient k may be selected to be a small value (for example, k = k ₁ ) so that the possibility of vehicle rollover is small.

On the other hand, when the vehicle V deviates from the traveling road and rolls over (specifically, in the case of a rollover such as coke screw, soil trip, embankment, etc.), the lateral acceleration Gy applied to the vehicle is about 1 According to the third embodiment, the coefficient k at this time is selected to be larger than the coefficient k ₁ when the lateral acceleration is small (depending on the characteristics of the filter, for example, less than 1 G). (For example, k = k ₂ > k ₁ ). Thus, the occupant protection device 3 according to the third embodiment determines that there is no possibility of vehicle rollover when the vehicle has a lateral acceleration Gy that hardly causes a rollover (for example, when | Gy | <1G), and deviates from normal driving. When the lateral acceleration Gy, which is determined to be likely to cause rollover, is sensed (for example, when | Gy |> 1G), the coefficient k is set so that the tendency to determine that there is a possibility of vehicle rollover is high. To change. That is, according to the occupant protection device 3 of the third embodiment, by selecting the coefficient k according to the value of the sensed lateral acceleration Gy, it is possible to further improve the determination accuracy of the possibility of vehicle rollover.

However, for example, when another vehicle collides sideways from the side, a lateral acceleration Gy substantially larger than the lateral acceleration Gy generated when the vehicle rolls over (for example, | Gy |> 3G) is generated. At this time, as described above, instead of deploying the curtain airbags on both sides of the side impacted vehicle, deploy only the side impacted curtain airbag and not deploy the non-collision side curtain airbag. Is preferable from an economic viewpoint. That is, in the case of a side collision, the occupant protection device 3 determines that the rollover determination condition is not satisfied, and the side-collision side curtain is prepared using a separately prepared side collision determination device (not shown). It is preferable to control so that only the airbag is deployed and the curtain airbag on the non-collision side is not deployed. This is because, when the occupant protection device 3 senses a substantially large lateral acceleration Gy (for example, | Gy |> 3G), the coefficient k is selected by the lateral acceleration Gy generated when the vehicle rolls over. _This is realized by setting it to be substantially smaller than ₂ (for example, k = k ₃ , k ₃ <k ₂ ).

As described above, the coefficient k included in the rollover determination condition is selected by the following sensed lateral acceleration Gy and can be expressed as a general function as shown below (see FIG. 11). .
k = k ₁ (in the normal driving state, when | Gy | <Gy ₁ )
k = k ₂ > k ₁ (when the possibility of rollover is high, Gy ₁ ≦ | Gy | ≦ Gy ₂ )
k = k ₃ <k ₂ (when it is highly likely that a side collision has occurred, Gy ₂ <| Gy |)

In the above embodiment, when | Gy | = Gy ₁ and | Gy | = Gy ₂ , the coefficient k has a discrete value. Alternatively, the following relational expression and As shown in FIG. 12, it may be set so as to change continuously depending on the lateral acceleration | Gy |.
k = k ₁ (in the normal running state, when | Gy | <Gy ₁₁ )
k = p × | Gy | + q (when Gy ₁₁ ≦ | Gy | ≦ Gy ₁₂ )
k = k ₂ > k ₁ (when the possibility of rollover is high, Gy ₁₂ ≦ | Gy | ≦ Gy ₂₁ )
k = −r × | Gy | + s (when Gy ₂₁ ≦ | Gy | ≦ Gy ₂₂ )
k = k ₃ <k ₂ (when it is highly likely that a side collision has occurred, Gy ₂₂ <| Gy |)
(P, r, s are positive constants, q is a constant)

Further, when the lateral acceleration Gy is Gy ₁₁ or more and Gy ₁₂ or less and when Gy ₂₁ or more and Gy ₂₂ or less, the coefficient k is described as a linear function of the lateral acceleration | Gy | However, the present invention is not limited thereto, and can be expressed as an arbitrary function such as a quadratic function or an exponential function.

Thus, according to the third embodiment, it is determined that there is no possibility of vehicle rollover when the vehicle has a lateral acceleration Gy that is unlikely to cause rollover, and vehicle rollover is possible when it has a lateral acceleration Gy that is likely to cause rollover. Therefore, it is possible to set the value of the coefficient k so that it can be easily determined that the occupant is safe, and the occupant protection device 3 for the vehicle V with higher safety can be provided.
In addition, when a side collision occurs, the tendency to determine that there is a possibility of vehicle rollover is reduced, and activation of the protection device activation unit 60 is suppressed in a situation where the curtain airbag does not need to be deployed. Since the value of the coefficient k can be set to, a more economical occupant protection device 3 for the vehicle V can be realized.
The occupant protection devices 1 to 3 according to the present invention can be installed in any vehicle.

It is a schematic sectional view of a vehicle cut along a plane perpendicular to the traveling direction of the vehicle. It is a block diagram which shows the structure of the passenger | crew protection device of the vehicle by Embodiment 1 of this invention. 5 is a ω-θ rollover determination map including an area for determining the possibility of vehicle rollover. 5 is a ω-Gy rollover determination map including an area for determining the possibility of vehicle rollover. It is a rollover determination map by (ω × θ) − (ω × Gy) including a region for determining the possibility of vehicle rollover. 3 is a block diagram illustrating a configuration of a rollover occurrence degree determination unit according to Embodiment 1. FIG. It is a rollover determination map by ω− (θ + kGy) including an area for determining the possibility of vehicle rollover. 6 is a block diagram showing an alternative configuration of a rollover occurrence degree determination unit according to Embodiment 1. FIG. 6 is a block diagram illustrating a configuration of a vehicle occupant protection device according to Embodiment 2. FIG. It is a block diagram which shows the structure of the safing determination part shown in FIG. It is a graph which shows the dependence with respect to the horizontal direction acceleration Gy of the coefficient k contained in rollover judging conditions. It is a graph which shows another dependence with respect to the horizontal direction acceleration Gy of the coefficient k contained in rollover judging conditions.

Explanation of symbols

1-3: Occupant protection device, 10: roll angular velocity sensor, 12: filter, 20: lateral acceleration sensor, 22: filter, 30: vertical acceleration sensor, 32: filter, 40: roll angle calculation unit, 50: rollover Occurrence determination unit, 51: first calculation unit, 52: second calculation unit, 53: multiplier, 54: adder, 55: comparator, 56: multiplier, 57: adder, 58: calculation unit , 59: comparator, 60: protection device activation unit, 70: safing determination unit, 80: AND logic circuit unit, V: vehicle, ω: roll angular velocity, θ: roll angle, Gy: lateral acceleration, Gz: up and down Direction acceleration, G: center of gravity, Hv: height of center of gravity, T: tread length.

Claims (5)

An occupant protection device for a vehicle, characterized by determining that the vehicle may roll over when the roll angle θ, the roll angular velocity ω, and the lateral acceleration Gy of the vehicle satisfy the following expressions.
(Ω × θ) + k (ω × Gy)> C or ω × (θ + k × Gy)> C
(K is a positive coefficient, C is a positive constant) 2. The vehicle occupant protection device according to claim 1, wherein when the lateral acceleration Gy and the vertical acceleration Gz of the vehicle satisfy the following expressions, it is determined that the vehicle may roll over.
| Gy | / Gz> 2Hv / T
(Hv is the height of the center of gravity of the vehicle, T is the tread length of the vehicle)   The vehicle occupant protection device according to claim 1, wherein the coefficient k is expressed as a function of a lateral acceleration Gy. The vehicle occupant protection device according to claim 3, wherein the coefficient k is expressed by the following function.
k = k ₁ (when | Gy | <Gy ₁ )
k = k ₂ > k ₁ (when Gy ₁ ≦ | Gy | ≦ Gy ₂ )
k = k ₃ <k ₂ (when Gy ₂ <| Gy |) The vehicle occupant protection device according to claim 3, wherein the coefficient k is expressed by the following function.
k = k ₁ (when | Gy | <Gy ₁₁ )
k = p × | Gy | + q (when Gy ₁₁ ≦ | Gy | ≦ Gy ₁₂ )
k = k ₂ > k ₁ (when Gy ₁₂ ≦ | Gy | ≦ Gy ₂₁ )
k = −r × | Gy | + s (when Gy ₂₁ ≦ | Gy | ≦ Gy ₂₂ )
k = k ₃ <k ₂ (when Gy ₂₂ <| Gy |)
(P, r, s are positive constants, q is a constant)

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