JP5643178B2 - Seat belt control device - Google Patents

Description

  The present invention relates to a seat belt control device that winds webbing using a motor.

  As a conventional control device for this type of seat belt, for example, one disclosed in Patent Document 1 is known. The seat belt has a rod for pressing the webbing, a motor for driving the rod, and a conversion mechanism for converting the rotation of the motor into a linear movement of the rod. In this control device, at the time of a vehicle collision, the motor is operated, the rod is moved toward the webbing by the conversion mechanism, the webbing is sandwiched between the rod and the receiving part, and the occupant moves forward. Suppress. Further, the driving force of the motor at that time is set according to the acceleration detected at the time of the collision and the occupant weight and the seat slide position detected and stored before the collision, thereby suppressing the movement of the occupant. Is to be done appropriately.

JP 2005-178514 A

  As described above, in this conventional control device, the motor required to hold the webbing at the time of the collision according to the acceleration detected at the time of the collision and the weight of the occupant and the slide position of the seat detected before the collision. Set the driving force. However, the tensile force acting on the webbing at the time of the collision changes according to the actual situation of the occupant at the time of the collision, and accordingly, the necessary driving force of the motor also changes. For example, when an occupant holds his arm or leg against a collision, the degree to which the impact is absorbed by the occupant increases and the webbing tensile force becomes smaller. Get smaller. On the other hand, when the occupant is not dressed, the impact is not absorbed so much and the tension of the webbing becomes larger, so that the necessary driving force of the motor becomes larger.

  Therefore, even if the driving force of the motor is set as in the conventional control device, the setting may not be performed properly. For example, when the driving force of the motor is insufficient, the webbing pull-out amount increases, so that the movement of the occupant cannot be appropriately suppressed. Moreover, when the driving force of the motor is excessive, the passenger feels uncomfortable that the webbing is locked suddenly.

  The present invention has been made to solve the above-described problems. When the behavior of the vehicle is in an unstable state, the posture of the occupant can be appropriately maintained without causing the occupant to feel uncomfortable. An object of the present invention is to provide a seatbelt control device that can be used.

In order to achieve the above object, the invention according to claim 1 is a seat belt having a motor 9 that operates when electric current is supplied and winds the webbing 5 around the reel 8 by rotating the reel 8. And a weight detection means (weight sensor) for detecting the weight (seat load WP) of the occupant (driver DR) acting on the seat (driver seat SE in the embodiment (hereinafter the same in this section)). 22), behavior determining means (ECU 2, step 3 in FIG. 3) for determining whether or not the behavior of the vehicle V is in an unstable state, and when it is determined that the behavior of the vehicle V is in an unstable state , A control means (ECU 2, step 5 in FIG. 3) for executing posture holding control for holding the posture of the occupant by supplying current to the motor 9 and winding the webbing 5 on the reel 8; Supply current setting means (ECU 2, steps 10 to 12 in FIG. 3) for setting a current (supply current ECM) to be supplied to the motor 9 based on the weight of the occupant detected during holding control (in-control seat load WCON) The supply current setting means includes the motor 9 as the weight of the occupant detected during the posture holding control is smaller than the weight of the occupant (reference load WSTN) detected when the posture holding control is not being performed. Is set to a larger value (steps 10 to 12 in FIG. 3) .

  According to this seat belt control device, when it is determined that the behavior of the vehicle is in an unstable state, the posture holding control for winding the webbing around the reel is executed by supplying a current to the motor. By this posture holding control, the tension of the wound webbing acts on the occupant, whereby the occupant's body is pulled back to the seat side, and the occupant's posture is maintained.

  Further, when the behavior of the vehicle becomes unstable and the posture of the occupant collapses, the weight of the occupant acting on the seat (hereinafter referred to as “seat load”) decreases accordingly. For example, if the occupant's upper body leans forward or left and right when the vehicle decelerates or turns, the weight supported by the occupant's legs increases, thereby reducing the seat load and increasing the occupant's upper body inclination. The greater the value, the greater the reduction in seat load. Thus, the seat load well represents the degree of occupant posture collapse. Therefore, by setting the current supplied to the motor based on the weight of the occupant detected during posture holding control, the webbing tension can be controlled without excess or deficiency in accordance with the degree of occupant posture collapse. . As a result, the body of the occupant is not pulled back to the seat side due to insufficient webbing tension, and the passenger does not feel uncomfortable due to excessive tension of the webbing. Therefore, when the behavior of the vehicle is unstable In addition, the occupant's posture can be appropriately maintained without causing the occupant to feel uncomfortable.

  As described above, the seat load well represents the degree of collapse of the occupant's posture. According to this configuration, the current supplied to the motor is set to a larger value as the weight of the passenger detected during the posture holding control is smaller than the weight of the passenger detected during the posture holding control. To do. Therefore, the occupant's body can be pulled back more strongly by increasing the tension of the webbing as the degree of collapse of the occupant's posture is estimated to be higher when the behavior of the vehicle is in a stable state. The holding control can be performed more appropriately.

1 is a side view schematically showing a seat belt control device according to an embodiment together with a driver's seat and a driver of a vehicle. It is a figure showing a seat belt and ECU roughly. It is a flowchart which shows a driver | operator's attitude | position holding | maintenance control process performed by ECU.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The seat belt 3 shown in FIG. 1 is of a so-called three-point type, and includes a webbing 5 for restraining the driver DR to the driver's seat SE and a retractor 6 for winding the webbing 5. The retractor 6 is attached to the lower part of the center pillar CP on the right side of the vehicle V. The webbing 5 extends upward from the retractor 6 and is passed through a through anchor TA attached to the upper portion of the center pillar CP. The front end portion of the webbing 5 is connected to the lower portion of the center pillar CP and an outer anchor (not shown). It is fixed through. The webbing 5 extends in the vertical direction along the center pillar CP in a non-wearing state where the webbing 5 is not applied to the driver DR.

  The webbing 5 is provided with a tongue plate TP between the through anchor TA and the outer anchor. The tongue plate TP is slidable in the length direction of the webbing 5 and is detachable from the buckle BU. The buckle BU is fixed to the front floor FF of the vehicle V, and is disposed near the passenger seat near the driver seat SE. In the seat belt 3 having the above configuration, the driver DR seated on the driver's seat SE pulls out the webbing 5 from the retractor 6 and engages the tongue plate TP with the buckle BU, whereby the webbing 5 is hung on the driver DR. . In this wearing state, the driver DR is restrained by the driver's seat SE by the webbing 5.

  As shown in FIG. 2, the retractor 6 includes a frame 7 fixed to the center pillar CP, a reel 8 around which the webbing 5 is wound, a motor 9 for rotating the reel 8, and the like. The reel 8 is rotatably supported by the frame 7 and is urged by a return spring (not shown) in a direction in which the webbing 5 is wound (hereinafter referred to as “winding direction”). By urging by the return spring, the webbing 5 is wound around the reel 8 after the seat belt 3 is released and stored in the center pillar CP.

  Further, the shaft portion 8 a of the reel 8 is connected to the output shaft 9 a of the motor 9 via the power transmission mechanism 10. The motor 9 is composed of, for example, a DC motor, converts the supplied current into power and outputs it from the output shaft 9a, and winds the webbing 5 together with the power transmission mechanism 10 when the vehicle V collides. This is an electric pretensioner.

  Furthermore, the power transmission mechanism 10 includes a mechanical clutch, a planetary gear device (none of which is shown), and the like. When the motor 9 rotates in the forward direction, the output shaft 9a of the motor 9 is connected to the shaft portion 8a of the reel 8 by this clutch, and the power of the motor 9 is transmitted to the reel 8 while being decelerated by the planetary gear device. The Thereby, the reel 8 is rotationally driven in the winding direction. On the other hand, when the motor 9 rotates in the reverse direction, the output shaft 9a and the shaft portion 8a are blocked by the clutch.

  In the seat belt 3 having the above-described configuration, when the vehicle V collides, the motor 9 rotates in the forward direction under the control of the ECU 2 so that the motor 9 and the reel 8 are connected by a clutch and the reel 8 is in the winding direction. Is driven to rotate. As a result, when the vehicle V collides, the driver DR moves forward and the webbing 5 is pulled out, while the power of the motor 9 acts on the webbing 5 as a load (braking force), so Is absorbed by the webbing 5. Further, as will be described later, when the behavior of the vehicle V is in an unstable state, the motor 9 is driven in the forward rotation direction to wind up the webbing 5 in order to maintain the posture of the driver DR.

  The retractor 6 is provided with a rotation angle sensor 21. The rotation angle sensor 21 has a plurality of magnetic poles formed at equal intervals along the circumferential direction, and is arranged in the vicinity of a magnetic disk (not shown) that rotates integrally with the reel 8 and the outer peripheral edge of the magnetic disk. A pair of Hall elements (not shown) are provided, and a pulse signal is output to the ECU 2 at every predetermined angle as the reel 8 rotates.

  A weight sensor 22 is embedded in the seat surface of the driver's seat SE. The weight sensor 22 is composed of a strain gauge or the like, detects the weight (hereinafter referred to as “seat load”) WP of the driver DR acting on the seat surface of the driver's seat SE, and outputs a detection signal to the ECU 2.

  Further, the ECU 2 outputs a detection signal representing the longitudinal acceleration Gx of the vehicle V from the longitudinal acceleration sensor 23, and a detection signal representing the lateral acceleration Gy of the vehicle V from the lateral acceleration sensor 24, respectively. .

  The ECU 2 is composed of a microcomputer including a CPU, a RAM, a ROM, an I / O interface (all not shown), and the like. The ECU 2 executes various arithmetic processes based on the control programs stored in the ROM in accordance with the detection signals of the various sensors 21 to 24 described above. In the present embodiment, the ECU 2 corresponds to behavior determination means, control means, and supply current setting means.

  Next, the attitude maintenance control process for the driver DR executed by the ECU 2 will be described with reference to FIG. In this control process, when the vehicle V decelerates or turns, the webbing 5 is wound up, and the upper body of the driver DR tilted forward or leftward is pulled back to the driver's seat SE side, and the posture of the driver DR is changed. It is to hold. This process is executed every predetermined time.

In this process, first, in step 1 (illustrated as “S1”, the same applies hereinafter), it is determined whether or not the posture holding control flag F_CON is “1”. When this answer is NO, in step 2, the detected accelerations Gx and Gy in the front-rear and left-right directions of the vehicle V are used to synthesize both accelerations Gx and Gy by the following equation (1) to calculate the vehicle acceleration GRES. To do.

  Next, in step 3, it is determined whether or not the vehicle acceleration GRES is larger than a predetermined first predetermined value GREFH (for example, 0.35 G). If the answer is NO and GRES ≦ GREFH, it is determined that the behavior of the vehicle V is in a stable state, and in step 4, the seat load WP detected at that time is set as the reference load WSTN, and this process is terminated. To do.

  On the other hand, if the answer to step 3 is YES and GRES> GREFH, it is determined that the behavior of the vehicle V is in an unstable state, and the posture holding control flag F_CON is set to “1” in order to start posture holding control. Set (step 5) and proceed to step 6.

  On the other hand, if the answer to step 1 is YES and the posture holding control is being executed, steps 3 and 5 are skipped and the process proceeds to step 6.

  In this step 6, the seat load WP at that time is set as the controlled seat load WCON, and in step 7, the ratio of the controlled seat load WCON to the reference load WSTN (= WCON / WSTN) is set as the seat load ratio RCON. calculate.

  Next, in step 8, it is determined whether or not the calculated seat load ratio RCON is larger than a predetermined first threshold value RREFH (for example, 0.8) that is smaller than 1.0. When the answer is YES and RCON> RREFH, since the seat load WCON during control is not so small with respect to the reference load WSTN, it is determined that the driver DR is in the first posture state in which the degree of collapse of the posture of the driver DR is low.

  In step 10, a supply current supplied to the motor 9 by multiplying a predetermined first basic current value KL (for example, 1.0 A) for the first posture state by the number of output pulses ΔN from the rotation angle sensor 21. ECM is calculated. This output pulse number ΔN is the number of pulse signals output from the rotation angle sensor 21 in the processing cycle from the previous time to the current time, and represents the amount of webbing 5 drawn in this processing cycle.

  On the other hand, when the answer to step 8 is NO, it is determined in step 9 whether the seat load ratio RCON is smaller than a predetermined second threshold value RREFL (eg, 0.6) that is smaller than the first threshold value RREFH. Is determined. If the answer is YES and RCON <RREFL, the in-control seat load WCON is considerably smaller than the reference load WSTN, and therefore it is determined that the driver DR is in the third posture state in which the posture collapse degree is high. In step 12, the predetermined third basic current value KH (for example, 3.0A) for the third posture state, which is larger than the first basic current value KL, is multiplied by the number of output pulses ΔN, so that the motor 9 is supplied. Supply current ECM is calculated.

  On the other hand, when the answer to step 9 is NO and RREFL ≦ RCON ≦ RREFH, it is determined that the driver DR is in the second posture state in which the degree of posture collapse is medium. In step 11, a predetermined second basic current value KM (for example, 2.0 A) for the second posture state between the first basic current value KL and the third basic current value KH is multiplied by the number of output pulses ΔN. As a result, the supply current ECM to the motor 9 is calculated.

  In step 13 following step 10, 11 or 12, it is determined whether or not the vehicle acceleration GRES is smaller than a predetermined second predetermined value GREFL (for example, 0.25 G) smaller than the first predetermined value GREFH used in step 3. Determine. When this answer is NO, it is determined that the behavior of the vehicle V is still in an unstable state, and the posture holding control is continued.

  On the other hand, when the answer to step 13 is YES, it is determined that the behavior of the vehicle V has returned to the stable state, the posture holding control is terminated, and the posture holding control flag F_CON is reset to “0” (step) 14) After that, this process is terminated.

  As described above, according to the present embodiment, when the vehicle acceleration GRES is larger than the first predetermined value GREFH, the posture holding control for winding the webbing 5 around the reel 8 is executed (step 3 in FIG. 3). As a result, when the behavior of the vehicle V is in an unstable state, the driver DR's upper body tilted forward or left and right is pulled back to the driver's seat SE side by the tension of the webbing 5 to change the posture of the driver DR. Can be held.

  Further, the basic current value (first to third basic current values KL, KM, KH) is set to a larger value as the seat load ratio RCON is smaller in accordance with the in-control seat load WCON detected during the posture holding control. By doing so, the supply current ECM to the motor 9 is set to a larger value (steps 6 to 12 in FIG. 3). Thereby, the tension of the webbing 5 can be controlled without excess or deficiency in accordance with the actual degree of collapse of the posture of the driver DR. Thereby, when the behavior of the vehicle V is in an unstable state, the driver DR's posture is not corrected due to insufficient tension of the webbing 5, and the driver DR does not feel uncomfortable due to excessive tension of the webbing 5. The posture can be appropriately maintained.

  Further, the seat load ratio RCON is a ratio of the seat load WCON during control and the reference load WSTN detected when the posture maintenance control is not being performed. Therefore, the degree of the posture collapse of the driver DR with reference to the reference load WSTN. Is estimated to be higher, the upper body of the driver DR can be pulled back more strongly, and posture holding control can be performed more appropriately.

  Further, since the supply current ECM to the motor 9 is calculated so as to be proportional to the number of output pulses ΔN, the tension of the webbing 5 can be increased as the actual pull-out amount of the webbing 5 increases, and the posture is maintained. Control can be performed more appropriately.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in the embodiment, the setting of the supply current ECM to the motor 9 is performed according to the seat load ratio RCON, which is the ratio of the in-control seat load WCON and the reference load WSTN. You may carry out according to the difference (= WSTN-WCON) of the reference | standard load WSTN and the sheet | seat load WCON in control. In that case, the supply current ECM is set to a larger value as the difference is larger.

  In the embodiment, the seat load WP immediately before the start of the attitude holding control is used as the reference load WSTN. However, the present invention is not limited to this. For example, when the vehicle V is in a stopped state (Gx = Gy = 0). The seat load WP may be used.

  In the embodiment, the determination as to whether or not the behavior of the vehicle V is in an unstable state is performed based on the vehicle acceleration GRES of the vehicle V, but is not limited thereto. You may perform based on a yaw rate.

  In addition, the embodiment is an example of a seat belt for a driver's seat of a vehicle, but the present invention may be applied to a seat belt for a passenger seat or a rear seat. Further, the present invention may be applied to a seat belt of a ship, an aircraft, or the like, or may be applied to a seat belt of an amusement park play facility. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

V Vehicle DR Driver (occupant)
1 control device 2 ECU (behavior determination means, control means, supply current setting means)
3 Seat belt 5 Webbing 8 Reel 9 Motor 22 Weight sensor (weight detection means)
WP Seat load (occupant weight acting on the seat)
Seat load during WCON control (occupant weight detected during posture maintenance control)
WSTN standard load (occupant weight detected when posture maintenance control is not in progress)
ECM supply current (current supplied to the motor)

Claims (1)

A control device for a seat belt having a motor which operates when supplied with an electric current and winds webbing around the reel by rotating the reel;
Weight detection means for detecting the weight of an occupant acting on the seat;
Behavior determination means for determining whether the behavior of the vehicle is in an unstable state;
Control means for performing posture holding control for holding the posture of an occupant by supplying current to the motor and winding the webbing on the reel when it is determined that the behavior of the vehicle is in an unstable state When,
Supply current setting means for setting a current to be supplied to the motor based on the weight of an occupant detected during the posture holding control ,
The supply current setting means increases the current supplied to the motor as the weight of the occupant detected during the posture holding control is smaller than the weight of the occupant detected when the posture holding control is not being performed. control device for a seat belt, characterized in that you set the value.

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