JP2011016449A - Seat belt device for vehicle and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat belt device for a vehicle which can suppress a sudden change of a current supplied to a motor even if a rotation sensor is failed during a control of the motor, and a control method thereof.SOLUTION: The seat belt device includes a rotation sensor 11 for detecting a rotation of a belt reel and a sensor abnormality detecting means 35 for detecting the abnormality of the rotation sensor 11. The seat belt device further includes a first current control means 36 for taking a detecting signal of the rotation sensor 11 as one feedback parameter to set a target current, and controlling a current so as to have the target current, and a second current control means 37 for setting the target current without using the detecting signal of the rotation sensor 11 to control the current so as to have the target current. When the sensor abnormality detecting means 35 detects the abnormality, current control is switched from the first current control means 36 to the second current control means 37, while suppressing the sudden change of the target current.

Description

  The present invention relates to a vehicle seat belt device that restrains an occupant seated in a vehicle by webbing and a control method thereof.

In recent years, as a seat belt device, a webbing that has been retracted by a motor as required to obtain appropriate occupant restraint according to the vehicle state has been developed (for example, see Patent Document 1).
Many seat belt devices of this type are provided with a rotation sensor that detects the rotation of the belt reel, and the target position (winding position) of the belt reel that is determined according to the vehicle state and the occupant state, and the rotation sensor. The detected current position of the belt reel is compared, the target current is corrected in consideration of the amount of deviation between them, and the energization current of the motor is controlled so as to be the target current.

JP 2006-290285 A

  However, since this type of conventional seat belt device controls the energization current of the motor using the detection signal of the rotation sensor as a feedback parameter, if a signal failure occurs due to any cause in the rotation sensor, the feedback parameter is The value may be different from the actual rotational position of the belt reel, and the energization current of the motor may increase more than necessary. If the motor energization current suddenly increases due to a failure of the rotation sensor, the webbing tension will fluctuate abruptly, causing discomfort to the occupant, and the operating noise may increase due to a sudden increase in motor rotation. Is done.

  Accordingly, the present invention provides a vehicle seat belt device and a control method thereof that can suppress a sudden change in the energization current of the motor even if the rotation sensor should malfunction during the control of the motor. Is.

The invention according to claim 1, which solves the above problem, includes a belt reel (for example, a belt reel 12 in an embodiment described later) around which a webbing is wound, and a rotation sensor (for example, a rotation sensor for detecting rotation of the belt reel). A rotation sensor 11) in a later-described embodiment, and a motor (for example, a motor 10 in a later-described embodiment) that rotates the belt reel, and a current that is supplied to the motor in accordance with a vehicle state or a passenger situation A vehicle seat belt device for controlling the sensor, wherein the sensor abnormality detecting means (for example, sensor abnormality detecting means 35 in an embodiment described later) for detecting abnormality of the rotation sensor and at least one detection signal of the rotation sensor A target current is set as a feedback parameter, and the current applied to the motor is controlled so that the target current is reached. First current control means (for example, first current control means 36 in an embodiment described later) and the target current is set without using the detection signal of the rotation sensor, and the motor is set to the target current. And a second current control means (for example, a second current control means 37 in an embodiment described later) for controlling the energization current of the motor, and controlling the energization current of the motor by the first current control means. When the sensor abnormality detecting means detects an abnormality of the rotation sensor under the situation, the current control by the second current control means is controlled from the current control by the first current control means while suppressing the sudden change of the target current. It is characterized by shifting to.
As a result, when the rotation sensor fails while the motor is being controlled by the first current control means, the motor of the second current control means that does not use the rotation sensor while avoiding a sudden change in current is avoided. Switch to control.

According to a second aspect of the present invention, in the vehicle seat belt device according to the first aspect of the present invention, the vehicular seat belt device includes a current sensor (for example, a current sensor 40 in an embodiment described later) that detects the amount of current that is supplied to the motor. The second current control means sets a target current based on a detection signal of the current sensor.
As a result, when an abnormality of the rotation sensor is detected by the sensor abnormality detection means, the current supplied to the motor is fed back, and the motor is controlled in consideration of the change in webbing tension by the second control means.

According to a third aspect of the present invention, in the vehicle seat belt device according to the second aspect, the sensor abnormality detection means is configured to control the energization current of the motor by the first current control means. When an abnormality of the rotation sensor is detected, a target correction component including the detection signal of the rotation sensor as a feedback parameter out of the target current set by the first current control unit immediately before the abnormality detection is invalidated, or the target The correction component is reduced, and after the motor is energized with the target current obtained there, the control is shifted to the current control by the second current control means.
Thus, even if the detection signal of the rotation sensor including the abnormality is extracted immediately before the abnormality of the rotation sensor is detected by the sensor abnormality detection means, the detection signal of the rotation sensor is fed back at this time. Since the target current is set by invalidating the target correction component included as a parameter or decreasing the target correction component, the current is passed through the motor with a target current that does not deviate significantly from the target current before the rotation sensor failure. The current control by the current control means 2 is executed.

According to a fourth aspect of the present invention, in the vehicle seat belt device according to the first aspect, the second current control means has a target current that changes suddenly during the transition from the current control by the first current control means. A plurality of energization patterns that are not to be stored are stored, and an energization pattern is selected according to the conditions at the time of transition to current control.
Thereby, when an abnormality of the rotation sensor is detected by the sensor abnormality detection means, an optimum one is selected from the energization patterns stored in advance according to the energization amount immediately before the failure, the target current, etc. The energization of the motor is continued by the selected energization pattern.

The invention according to claim 5 includes a belt reel around which webbing is wound, a rotation sensor that detects rotation of the belt reel, and a motor that rotationally drives the belt reel. A target current is set using at least one feedback parameter as a detection signal of the rotation sensor, and the current applied to the motor is controlled to be the target current. Determining whether there is an abnormality in the rotation sensor, and setting a target current by excluding the detection signal of the rotation sensor as a feedback parameter when there is an abnormality determination in the step. It is characterized by including.
Thereby, when a failure is determined in the step of determining whether or not there is a failure in the rotation sensor, it is prohibited to use the detection signal of the rotation sensor as a feedback parameter in the next step, using another feedback parameter, or The energization control of the motor is executed with the energization pattern fixed in advance.

According to a sixth aspect of the present invention, in the control method for a vehicle seatbelt device according to the fifth aspect, the motor is energized so that the target current is set by excluding the detection signal of the rotation sensor. And a step of notifying the abnormality of the rotation sensor based on the determination result of the presence / absence of the abnormality after the execution of the energization is completed.
This prevents the rotation sensor from being notified of abnormality while the motor is energized.

  According to the first aspect of the present invention, when an abnormality of the rotation sensor is detected during the motor control by the first current control means, the detection signal of the rotation sensor is generated while suppressing a sudden change in the target current. Since the process moves to the second current control means that is not used as a feedback parameter, a sudden change in the energization current of the motor can be suppressed even if the rotation sensor should malfunction during the control of the motor. Therefore, it is possible to improve passenger comfort and reduce motor noise when the rotation sensor fails.

  According to the second aspect of the present invention, when the rotation sensor fails, the second current control means sets the target current based on the detection signal of the current sensor and controls the motor in consideration of the change in the webbing tension. Since it can be switched, the uncomfortable feeling given to the occupant can be further reduced.

  According to the third aspect of the present invention, when the abnormality of the rotation sensor is detected by the sensor abnormality detection means, the detection of the rotation sensor out of the target current set by the first current control means immediately before the abnormality detection. Since the target correction component including the signal as a feedback parameter is invalidated or the target correction component is decreased and the motor is energized with the target current obtained there, the current control is performed by the second current control unit. A sudden change in the target current at the time of control transition can be reliably suppressed.

  According to the fourth aspect of the present invention, since the optimum one is selected from the energization patterns stored in advance when an abnormality of the rotation sensor is detected, the target current suddenly increases with a simple configuration. Control can be transferred from the first current control means to the second current control means without causing a significant change.

  According to the fifth aspect of the present invention, when a failure of the rotation sensor is determined, it is prohibited to use the detection signal of the rotation sensor as a feedback parameter thereafter, using another feedback parameter, or in advance Since the energization control of the motor is executed with the set energization pattern, even if the rotation sensor should break down during motor control, a sudden change in the energization current of the motor is suppressed, and passenger comfort is improved. Improvement and reduction of motor noise can be achieved.

  According to the sixth aspect of the invention, when a failure of the rotation sensor is detected, an abnormality of the rotation sensor is notified after the energization control of the motor is completed, so that an emergency or vehicle state is unstable. Even under circumstances, the crew can be concentrated on driving.

1 is a schematic configuration diagram of a seat belt device according to an embodiment of the present invention. It is a schematic block diagram of the retractor and controller of the seatbelt apparatus of one Embodiment of this invention. It is a schematic block diagram of the retractor of the seatbelt apparatus of one Embodiment of this invention. It is a figure for demonstrating the process of the pulse signal of the rotation sensor of one Embodiment of this invention. FIG. 5 is a view similar to FIG. 4 when a signal failure occurs on the B-phase side of the rotation sensor of one embodiment of the present invention. It is a figure for demonstrating the process of the pulse signal of the rotation sensor of one Embodiment of this invention. It is a figure which shows the displacement of a webbing, and the change of an electric current value when a rotation sensor fails in the middle of the motor control of the seatbelt apparatus of one Embodiment of this invention. It is a flowchart which shows the flow of control of the seatbelt apparatus of one Embodiment of this invention. It is a flowchart which shows the flow of control of the seatbelt apparatus of one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall schematic configuration of a seat belt device 1 according to the present invention. In FIG. 1, reference numeral 2 denotes a seat on which an occupant 3 is seated. The seat belt device 1 of this embodiment is a so-called three-point seat belt device, and a webbing 5 is drawn upward from a retractor 4 attached to a center pillar (not shown), and the webbing 5 is supported on the upper side of the center pillar. The tip of the webbing 5 is fixed to the vehicle body floor via an outer anchor 7 near the outside of the passenger compartment of the seat 2. A tongue plate 8 is inserted between the through anchor 6 and the outer anchor 7 of the webbing 5, and the tongue plate 8 can be attached to and detached from the buckle 9 fixed to the vehicle body floor of the seat 2 on the inner side of the vehicle body. It has become.
The webbing 5 is wound around the retractor 4 in the initial state, and the occupant 3 pulls it out by hand to fix the tongue plate 8 to the buckle 9, thereby restraining the chest and abdomen mainly of the occupant 3 with respect to the seat 2. To do. Further, the seat belt device 1 automatically performs the winding adjustment of the webbing 5 by the electric motor 10 when the behavior of the vehicle becomes unstable.

  As shown in FIG. 2, the retractor 4 has a webbing 5 wound around a belt reel 12 rotatably supported by a casing (not shown), and a shaft of the belt reel 12 projects from one end side of the casing. . The belt reel 12 is connected to the rotating shaft 10 a of the motor 10 via a power transmission mechanism 13 so as to be interlocked. The power transmission mechanism 13 decelerates the rotation of the motor 10 and transmits it to the belt reel 12. Further, the retractor 4 is provided with a winding spring (not shown) that urges the belt reel 12 in the webbing winding direction. When the belt reel 12 and the motor 10 are separated by a clutch 20 described later, the retractor 4 Tension acts on the webbing 5.

The retractor 4 is provided with a rotation sensor 11 that detects the rotational position of the belt reel 12. The rotation sensor 11 includes, for example, a magnetic disk in which different magnetic poles are alternately magnetized along the circumferential direction and rotates integrally with the belt reel 12, and a pair disposed in the vicinity of the outer peripheral edge of the magnetic disk. And a sensor circuit for processing a detection signal of the Hall element, and a pulse signal processed by the sensor circuit is output to the controller 21.
In this case, the pulse signal input from the sensor circuit to the controller 21 according to the rotation of the belt reel 12 is used to detect the rotation amount (rotation position), rotation speed, rotation direction, and the like of the belt reel 12. That is, the controller 21 detects the amount of rotation of the belt reel 12 (the amount of winding / drawing of the webbing 5) by counting the pulse signal, and calculates the change rate (frequency) of the pulse signal to calculate the belt reel. 12 is obtained, and the rotation direction of the belt reel 12 is detected by comparing the rising edges of the waveforms of both pulse signals.

FIG. 3 shows a specific configuration of the power transmission mechanism 13.
In the power transmission mechanism 13, a sun gear 14 is integrally coupled to an external tooth 15 for driving input, and a carrier 17 that supports a plurality of planetary gears 16 is coupled to the shaft of the belt reel 12. A plurality of ratchet teeth (not shown) are formed on the outer peripheral side of the ring gear 18 meshed with the planetary gear 16, and these ratchet teeth constitute a part of the clutch 20. The clutch 20 appropriately disconnects the power transmission system between the motor 10 and the belt reel 12 by controlling the driving force of the motor 10 by the controller 21.

  The motor-side power transmission system 22 of the power transmission mechanism 13 is capable of rotating coaxially and integrally with the first connect gear 23 having a small diameter that is always meshed with the external teeth 15 that are integral with the sun gear 14. A large-diameter second connect gear 24, and first and second idler gears 26 that are between the second connect gear 24 and the motor gear 25 (integrated with the rotating shaft 10a of the motor 10) and are always meshed so as to be able to transmit power. 27. The driving force in the forward direction of the motor 10 is transmitted to the second and first connect gears 24 and 23 through the gears 25, 27 and 26, and further transmitted to the sun gear 14 through the external teeth 15, and then to the planetary gear 16. It is transmitted to the belt reel 12 through the carrier 17. The driving force in the forward rotation direction of the motor 10 rotates the belt reel 12 in the direction in which the webbing 5 is pulled. However, the driving force transmitted from the sun gear 14 to the planetary gear 16 is all transmitted to the carrier 17 side as described above when the ring gear 18 is fixed. However, when the ring gear 14 is free to rotate, the planetary gear is transmitted. The ring gear 18 is idled by 16 rotations. The clutch 20 controls the locking and unlocking of the rotation of the ring gear 14 to turn on / off the transmission of the motor driving force to the belt reel 12 (carrier 17).

  The clutch 20 includes the above-described ratchet teeth provided on the outer periphery of the ring gear 18 and a pawl (not shown) that is rotatably supported by a casing (not shown) and whose tip portion can mesh with the ratchet teeth. The meshing with the ratchet teeth is triggered by the rotation in the forward rotation direction of 10, and the meshing with the ratchet teeth is released by the rotation in the reverse rotation direction of the motor 10. Therefore, once the motor 10 is driven in the forward direction, the clutch 20 locks the ring gear 18 to maintain the motor 10 and the belt reel 12 in the connected state, and then when the motor 10 is driven in the reverse direction. Then, the lock of the ring gear 18 is released, and the motor 10 and the belt reel 12 are cut off.

  Incidentally, on the input side of the controller 21, as shown in FIG. 2, in addition to the rotation sensor 11, a longitudinal acceleration sensor 30 for detecting the longitudinal acceleration of the vehicle, and a lateral acceleration for detecting the lateral acceleration of the vehicle. A sensor 31, a yaw rate sensor 32 that detects angular acceleration in the yaw direction of the vehicle, a buckle switch 33 that detects attachment / detachment of the tongue plate 8 to / from the buckle 9, a current sensor 40 that detects current supplied to the motor 10, and the like are connected. ing. In addition, the controller 21 transmits and receives signals to and from controllers of other systems such as a VSA (Vehicle Stability Assist) system 34 through an in-vehicle communication network.

  The controller 21 includes a sensor abnormality detection unit 35 that detects an abnormality of the rotation sensor 11, a first current control unit 36 that controls an energization current of the motor 10 under a situation where the rotation sensor 11 is operating normally, And a second electric energy control means 37 for controlling the energization current of the motor 10 when the rotation sensor 11 fails. Further, a warning lamp 41 (abnormality notification means) is connected to the output side of the controller 21. The sensor abnormality detection means 35 outputs an abnormality determination signal when a failure of the rotation sensor 11 is detected, and the warning lamp 41 is turned on in response to the abnormality determination signal. However, when an abnormality is detected by the sensor abnormality detection means 35 during the energization control of the motor 10, the warning lamp 41 is turned on when the energization control of the motor 10 is completed.

  The sensor abnormality detection means 35 detects an abnormality of signals output from the pair of Hall elements of the rotation sensor 11. Here, if the signal system connected to one Hall element is referred to as A phase and the signal system connected to the other Hall element is referred to as B phase, the sensor abnormality detecting means 35 is connected to the A phase of the rotation sensor 11, A time-series change of the B-phase pulse is determined, and it is determined that there is an abnormality in the rotation sensor 11 when a pattern of both-phase pulse changes that cannot normally occur is generated.

4A and 4B show an example of changes in the A-phase and B-phase pulses of the rotation sensor 11 when 0 and 1 are associated with the Hi value and Low value of the pulse, respectively. The change of the corresponding value of each phase is shown in (C) and (D), the corresponding value of A phase and B phase is a binary number, and the corresponding value of A phase is a number one digit higher than the corresponding value of B phase. If there is, a value obtained by adding the corresponding values of both phases and converting them into decimal numbers (hereinafter simply referred to as “added value of A phase and B phase”) is shown in (E).
As shown in these figures, assuming that the pulse waveforms of the A phase and the B phase are those when the rotation sensor 11 rotates forward (rotates in one direction), the added value of the A phase and the B phase is 3 → 2 → 0 → 1..., And when the rotation sensor reverses, the added value of the A phase and the B phase changes from 3 → 1 → 0 → 2.
Further, in this example, when the addition value of the A phase and the B phase changes from 3 → 2 → 0 → 1 ... (forward rotation), the change of the addition value (previous value−current value) is set to +1. When the addition value of the A phase and the B phase changes from 3 → 1 → 0 → 2 ..., the change of the addition value (previous value−current value) is set to −1, and FIG. The change of the added value during forward rotation (previous value-current value) is shown. Further, (G) in FIG. 4 shows a value obtained by counting a change in the added value of the A phase and the B phase. The total pulse count value changes according to the amount of rotation of the belt reel 12, and increases during forward rotation and decreases during reverse rotation.

  Moreover, the correspondence between the change in the added value of the A phase and the B phase (previous value−current value) and the count value is as shown in FIG. In the case where there is no difference between the previous value and the current value, and the pattern of the previous value and the current value, which cannot be normal, 0 is set.

FIG. 5 is a diagram illustrating (A) to (G) corresponding to FIG. 4 when the B phase of the rotation sensor 11 has failed (failed while remaining Low output).
At the time of failure of the B phase of the rotation sensor 11, as shown in FIG. 5D, the corresponding value of the B phase pulse is always 1, and the added value of the A phase and the B phase is (E) of FIG. As shown in FIG. 5, 1 → 3 → 1..., And the change of the added value (previous value−current value) may be 1 or −1 as shown in FIG. Therefore, as shown in FIG. 5G, the total pulse count value does not increase to 1 or more even when the belt reel 12 rotates, and does not decrease to −1 or less.
In addition, although illustration is abbreviate | omitted here, it is the same also when the A phase of the rotation sensor 11 fails.
The sensor abnormality detection means 35 of this embodiment determines that one of the A phase and B phase of the rotation sensor 11 is abnormal when the total pulse count value fluctuates within a range of −1 or more and 1 or less.

The first current control means 36 sets a reference target current based on the vehicle state signal output from the lateral acceleration sensor 31, the yaw rate sensor 32, etc., and sets the reference target current as the following (a) to ( Using c), the current is sequentially corrected, and the current value of the motor 10 is controlled with the corrected value as the final target current.
(A) A deviation amount between the target position X1 of the belt reel 12 (target winding position of the webbing 5) and the current position X.
(B) A deviation amount between the target speed V1 of the belt reel 12 (the target winding speed of the webbing 5) and the current speed V.
(C) A deviation amount between the target current I1 energized to the motor 10 and the actual current I detected by the current sensor 40.
That is, in the first current control means 36, the current position X and current speed V of the belt reel 12 and the current conduction current I to the motor 10 are used as feedback parameters.

  On the other hand, since the second current control means 37 is used for control when the rotation sensor 11 is out of order, the second current control means 37 does not use the detection signal of the rotation sensor 11 (the current position X of the belt reel 12 and the current position). The current supplied to the motor 10 is controlled (without using the speed V as a feedback parameter).

  Specifically, for example, when the current sensor 40 has not failed, the reference target current is corrected using only the above (c), and the corrected value is used as the final target current. When the energization current is controlled and the current sensor 40 is out of order, the energization control is performed according to the energization pattern stored in advance in the storage unit of the controller 21. A plurality of types of energization patterns used here are stored in the form of a map, for example, and when shifting from the control by the first control means 36 to the control by the second control means 37 according to the vehicle state at that time or the like. A current that does not change suddenly (selected current) is selected.

Hereinafter, an example of the control by the controller 21 of the seat belt apparatus will be described with reference to the flowcharts of FIGS. Note that the control in this example assumes, for example, a situation where the vehicle travels on a continuous curved road or a slippery road surface.
In step S101 in FIG. 8, signals from sensors such as the rotation sensor 11, the lateral acceleration sensor 31, and the yaw rate sensor 32 are read. In subsequent step S102, an occupant restraint caused by an operation request of the motor 10, that is, a change in the vehicle state or the like. Determine if there is a request. At this time, in the case of No, it waits, and in the case of Yes, it progresses to step S103.
In step S103, the target position X1 of the belt reel 12, the target rotational speed V1, and the initial energization amount I0 for the motor 10 are set according to the vehicle state and the like, and energization to the motor 10 is started in step S104.

  In the subsequent step S105, it is determined whether or not the abnormality flag of the rotation sensor 11 is invalid. This abnormality flag is sequentially determined by an abnormality determination process (FIG. 9) described later. If Yes in step S105, the process proceeds to step S106. If No, the process proceeds to step S107.

In step S106, a reference target current is set (updates the control current target) according to the vehicle state and the like. When the webbing 5 is wound at an emergency or at a high speed, the reference target current is set so as to reach the target position X1 early, and when the webbing 5 is held at a predetermined winding position, the target The reference target current is set with emphasis on the position X1, and when the webbing 5 is wound at a constant speed, the reference target current is set with emphasis on the target speed V1.
In the next step S108, a final target current is determined by adding or subtracting a current correction allowance ΔI set in step S110 described later to the reference target current set in step S106. The failure detection cycle is preferably shorter than the adjustment cycle of the current correction allowance ΔI.
In the following step S109, it is determined whether or not the deviation amount between the target position X1 of the belt reel 12 and the current position X exceeds a specified range. If yes, the process proceeds to step S111 after step S110. In No, it progresses directly to step S111.
In step S110, the current correction allowance ΔI is determined. The current correction allowance ΔI is the amount of deviation between the target current I1 and the current current I (I1−I) and the amount of deviation between the target position X1 and the current position X. It is determined by taking into account (X1-X) and the amount of deviation (V1-V) between the target speed V1 and the current speed V.
In step S111, it is determined whether or not the motor control end condition has been reached. If Yes, the process returns to step S105, and if No, the process proceeds to step S112. The processing after step S112 will be described later.
A series of control from step S106 to step S110 corresponds to the function of the first current control means 36.

  If it is determined in step S105 that the abnormality flag is valid and the process proceeds to step S107, it is determined in step S107 whether or not the current sensor 40 is normal. If yes, the process proceeds to step S113. In No, it progresses to step S114. Note that the determination of whether or not the current sensor 40 is normal (determination of the abnormality flag) uses the result of an abnormality determination process (FIG. 9) described later.

In step S113, it is determined whether or not the current motor control is the winding control of the webbing 5. If Yes, the process proceeds to step S115. If No, the process proceeds to step S116.
When the process proceeds to step S115, the reference target current is set according to the vehicle state or the like (updates the control current target) as in step S106.
In the next step S117, the final target current is determined by adding or subtracting the current correction allowance ΔI to the reference target current set in step S115.
However, when it is determined in step S105 that the abnormality flag is valid for the first time, the current correction allowance ΔI is not added or subtracted in step S117. This is because when the abnormality flag is determined to be valid for the first time, the current correction allowance ΔI of step S110, in which the detection signal of the rotation sensor 11 is added to the feedback parameter, the abnormality signal of the rotation sensor 11 may be added. This is because the current correction allowance ΔI increases rapidly when an error signal is added. In this example, it is determined that the abnormality flag is valid and the initial current correction allowance ΔI is not added or subtracted. However, ΔI multiplied by a coefficient α (α <1) is added or subtracted. You may make it do.
In the next step S118, it is determined whether or not the deviation amount between the target current I1 and the current current I exceeds the specified range. If yes, the process proceeds to step S111 after step S119. Advances directly to step S111.
In step S119, the current correction allowance ΔI is determined. The current correction allowance ΔI is determined by taking into account only the deviation (I1−I) between the target current I1 and the current current I.

  If it is determined in step S113 that the winding control is not performed and the process proceeds to step S116, the current correction allowance ΔI ′ is subtracted from the current current I until the current reaches a substantially minimum current at which the clutch 20 can be maintained. To do. When the energization current of the motor 10 is set to a minimum value that can maintain the clutch 20 in the connected state, the winding force by the motor 10 does not act on the webbing 5, but the motor 10 does not pull out the webbing 5. On the other hand, it will act as a load.

  On the other hand, if it is determined in step S107 that the current sensor 40 is abnormal and the process proceeds to step S114, it is suitable for the current vehicle state from among a plurality of energization patterns stored in the storage unit and before failure determination. The one whose current does not change suddenly with respect to the energizing current is selected. And after finishing the process of step S114, it progresses to step S111.

When the energization control of the motor 10 is finished and the process proceeds to step S112, it is determined again whether or not the abnormality flag is invalid. In the case of Yes, the process returns after step S120. Returns as is.
In step S120, the notification lamp 41 is turned on to notify the user that there is an abnormality in the rotation sensor 11 or the like.

Next, the abnormality determination process shown in FIG. 9 will be described.
In step S201, a timer for measuring the elapsed time is started, and an operation signal of a motor or the like and a sensor signal are read.
Subsequently, in step S202, it is determined whether or not the motor 10 is energized. If yes, the process proceeds to step S203, and if no, the process returns.
In step S203, it is determined whether or not there is a detected current from the current sensor 40. If Yes, the process proceeds to step S204. If No, the process proceeds to step S205. In step S205, since there is a failure in the system of the current sensor 40, the process returns after enabling the failure flag.

  In step S204, it is determined whether or not there is a pulse output from the rotation sensor 11. If Yes, the process proceeds to step S206, and if No, the process proceeds to step S207. In step S207, since no pulse is output from either the A phase or the B phase of the rotation sensor 11, the process returns after enabling the failure flag.

  In step S206, it is determined whether or not the total pulse count value (see (G) in FIGS. 4 and 5) is not less than −1 and not more than 1. If Yes, the process proceeds to step S208. The process proceeds to step S209. In step S209, since both the A phase and B phase of the rotation sensor 11 are normal, the process returns after invalidating the abnormality flag.

  If the process proceeds from step S206 to step S208, there is a high possibility that one of the A phase and B phase of the rotation sensor 11 has a failure. In step S208, whether the same determination has continued beyond the predetermined time tth. If it is Yes, the process proceeds to Step S210. If it is No, the process returns to Step S202. In step 210, since it is determined that one of the A phase and B phase of the rotation sensor 11 has a failure, the process returns after enabling the abnormality flag.

  As described above, in the seat belt device 1, when the rotation sensor 11 fails during the control of the motor 10, the current control by the first current control means 36 that uses the detection signal of the rotation sensor 11 as a feedback parameter. Since the detection signal of the rotation sensor 11 is switched to the current control by the second current control means 37 that does not use the feedback parameter as a feedback parameter, the energization current changes rapidly due to the abnormal signal of the rotation sensor 11 during the control of the motor 10. Can be prevented.

  In particular, in the seat belt device 1, the current correction allowance ΔI calculated immediately before detecting the abnormality of the rotation sensor 11 is invalidated when the control is transferred from the first current control unit 36 to the second current control unit 37. Alternatively, the target current is set by decreasing the current, and the current control by the second current control unit 37 is performed after the energization is performed with the target current. Even when an abnormal signal has been extracted, it is possible to eliminate the problem that the target current increases rapidly due to the abnormal signal.

FIG. 7 shows a change in the energization current to the motor 10 and the displacement of the webbing 5 when the rotation sensor 11 fails during the winding control of the webbing 5 by the seat belt device 1. The two-dot chain line of the current value describes the change in the energization current of the seat belt device that does not have the second current control means 37 as a comparative example.
As is clear from this figure, in the seat belt device 1 of this embodiment, even if the rotation sensor 11 fails during motor control, a sudden change in the energization current can be reliably suppressed.
Therefore, in the seatbelt device 1, it is possible to prevent the passenger from feeling uncomfortable due to a sudden change in the webbing tension or to generate noise due to the motor 10 rotating at a high speed.

  Further, in the case of the seat belt device 1, when the rotation sensor 11 fails, the second control means 37 sets the target current using the current detected by the current sensor 40 as a feedback parameter. The motor 10 can be controlled, and control with less discomfort for the passenger can be realized.

  In the seat belt device 1, when the abnormality of the rotation sensor 11 is detected by the sensor abnormality detection unit 35 during the energization control of the motor 10, the warning lamp 41 is not immediately turned on, but the motor 10 Since the warning lamp 41 is lit after the complete energization control is completed, the occupant can be concentrated on driving even in an emergency or in a situation where the vehicle state is unstable.

  In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary. For example, in the above-described embodiment, the second current control unit 37 performs current control using the energization current as a feedback parameter. However, the second current control unit 37 is set in advance in the same manner as the control in step S114 when the current sensor 40 fails. You may make it perform electricity supply of the motor 10 with an electricity supply pattern. In this case, it is possible to prevent a rapid change in the target current when the rotation sensor 11 is out of order while having a relatively simple configuration that does not cause an increase in cost.

DESCRIPTION OF SYMBOLS 1 ... Seat belt apparatus 10 ... Motor 11 ... Rotation sensor 12 ... Belt reel 35 ... Sensor abnormality detection means 36 ... 1st electric current control means 37 ... 2nd electric current control means 40 ... Current sensor

Claims (6)

A belt reel around which webbing is wound;
A rotation sensor for detecting the rotation of the belt reel;
A motor that rotationally drives the belt reel,
A vehicle seat belt device for controlling a current to be supplied to the motor according to a vehicle state or a passenger condition,
Sensor abnormality detection means for detecting abnormality of the rotation sensor;
A first current control unit configured to set a target current using the detection signal of the rotation sensor as at least one feedback parameter, and to control an energization current of the motor so as to be the target current;
A second current control means for setting a target current without using the detection signal of the rotation sensor and controlling the energization current of the motor so as to be the target current;
When the sensor abnormality detection unit detects an abnormality in the rotation sensor under the situation where the current flowing through the motor is controlled by the first current control unit, the first change is made while suppressing a sudden change in the target current. A vehicle seat belt apparatus, wherein the current control by the current control means is shifted to the current control by the second current control means. A current sensor for detecting the amount of current passed through the motor;
The vehicle seat belt device according to claim 1, wherein the second current control means sets a target current based on a detection signal of the current sensor.   When the sensor abnormality detection means detects an abnormality of the rotation sensor under the situation where the current flowing to the motor is controlled by the first current control means, the first current control means immediately before detecting the abnormality. Of the set target current, the target correction component including the detection signal of the rotation sensor as a feedback parameter is invalidated or the target correction component is reduced, and the second energization is performed after the motor is energized with the target current obtained there. The vehicle seat belt device according to claim 2, wherein the vehicle is shifted to current control by the current control means.   The second current control means stores a plurality of energization patterns in which the target current does not change suddenly when shifting from the current control by the first current control means, and energizes according to the conditions at the time of the current control transition. The vehicle seat belt device according to claim 1, wherein a pattern is selected. A belt reel around which webbing is wound;
A rotation sensor for detecting the rotation of the belt reel;
A motor that rotationally drives the belt reel,
A vehicle seat belt device that sets a target current using the detection signal of the rotation sensor as at least one feedback parameter in accordance with a vehicle state or an occupant situation, and controls a current supplied to the motor so as to be the target current. Control method,
Determining whether the rotation sensor is abnormal;
And a step of setting a target current by excluding a detection signal of the rotation sensor as a feedback parameter when it is determined that there is an abnormality in the step. . Executing energization of the motor so as to achieve a target current set by excluding the detection signal of the rotation sensor;
The vehicle seat belt device control according to claim 5, further comprising a step of notifying an abnormality of the rotation sensor based on a determination result of the presence or absence of the abnormality after the execution of the energization is completed. Method.

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