JP2008238866A - Seat belt device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat belt device capable of preventing the adhesion of grease or worn powder and the like to a rotation detecting means, and the invasion of magnetic noise. <P>SOLUTION: The seat belt device is provided with a belt reel 4 around which a webbing 3 is wound, the rotation detecting means 14 detecting a rotation state of the belt reel 4, and a wind-up spring 15 energizing the belt reel 4 to rotate in a wind-up direction of the webbing 3. The rotation detecting means 14 is composed of a rotor 11 rotating by interlocking with the belt reel 4 and having different magnetism according to a position in a circumferential direction, and Hall elements 13A, 13B detecting magnetism change according to a rotation state of the rotor 11. The wind-up spring 15 is united to a coupling shaft 12 of the rotor 11 at one end. Between the rotation detecting means 14 and the wind-up spring 15, a partition wall 20 made from magnetic material is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a seat belt device for restraining an occupant seated on a vehicle seat by webbing.

  In a seat belt device installed in a vehicle, an occupant-restraining webbing is wound around a belt reel in a retractor, and is pulled out of the retractor when mounted. In this type of seat belt device, a rotating shaft projects from one end of a belt reel, and the rotating shaft is urged to rotate by a take-up spring.

  In recent years, a seat belt apparatus of this type has been developed in which a motor is connected to a rotating shaft of a belt leak via a clutch, and the webbing is loosened or urgently retracted by the power of the motor (for example, Patent Document 1). reference).

This seat belt device is provided with a clutch for connecting / disconnecting motor power to a rotating shaft projecting from a belt reel, and between the clutch and the take-up spring, the rotational state (rotation direction and amount of rotation) of the belt reel. , A rotation detecting means for detecting the rotation speed, etc., and a detection result of the rotation detecting means is outputted to a controller for motor control. The rotation detecting means includes a magnetic rotating body having different magnetism according to the position in the circumferential direction, and a magnetic sensor such as a Hall element that detects a magnetic change according to the rotation of the magnetic rotating body, and the magnetic rotating body is a belt. It is integrally attached at a position between the clutch and the take-up spring on the rotation shaft of the reel. Accordingly, when the belt reel rotates in accordance with the webbing feeding and winding, the magnetic rotating body rotates integrally with the belt reel, and the magnetic change around the magnetic rotating body at that time is output to the controller through the magnetic sensor. The rotation state of the belt reel is grasped at.
Japanese Patent Laid-Open No. 2005-297881

  However, in this conventional seat belt device, the winding spring and the rotation detecting means are disposed adjacent to each other on the rotation axis of the belt reel, so that the winding spring and grease or wear powder applied around the winding spring are not present. In addition to the possibility of adhering to the rotation detection means, there is a possibility that magnetic noise may enter the rotation detection means from the winding spring direction.

  Therefore, the present invention is intended to provide a seat belt device capable of preventing adhesion of grease, wear powder, and the like to the rotation detecting means and intrusion of magnetic noise.

The invention according to claim 1, which solves the above problem, is a belt reel (e.g., described later) in which a webbing (e.g., webbing 3 in an embodiment described later) is wound and the webbing is fed and unwound according to the rotation. Belt reel 4) in the embodiment, rotation detection means for detecting the rotation state of the belt reel (for example, rotation detection means 14 in the embodiment described later), and rotation urging of the belt reel in the direction of winding the webbing. A rotation spring (for example, a winding spring 15 in an embodiment described later), and the rotation detecting means rotates in conjunction with the belt reel, and the magnetic rotation differs depending on the position in the circumferential direction. A body (for example, a rotor 11 in an embodiment described later) and a magnetic sensor (for example, a rear sensor) that detects a magnetic change according to the rotation state of the magnetic rotating body. Seat belt in which one end of the winding spring is coupled to a shaft (for example, a coupling shaft 12 in an embodiment described later) that rotates integrally with the magnetic rotating body. In the apparatus, a partition wall made of a magnetic material (for example, a partition wall 20 in an embodiment described later) is provided between the rotation detection unit and the winding spring.
As a result, the rotation detecting means and the take-up spring are physically separated by the partition wall and are also shielded magnetically.

According to a second aspect of the present invention, in the seat belt device according to the first aspect, the rotation detecting means and the partition are accommodated in a common cover (for example, a front cover 16 in an embodiment described later). It is characterized by.
As a result, the rotation detection means and the take-up spring are partitioned into different spaces within the cover.

According to a third aspect of the present invention, in the seatbelt device according to the second aspect, a support wall (for example, an arc in an embodiment described later) is provided in the cover so as to abut on the peripheral edge of the partition wall from the rotation detecting means side. Walls 23b and 25a) are provided.
Thereby, the peripheral part of a partition is supported by a support wall from the rotation detection means side, and deformation | transformation, such as curvature of the peripheral part of a partition, is prevented.

According to a fourth aspect of the present invention, in the seatbelt device according to the third aspect, a holding case (for example, a holding case 25 in an embodiment described later) of the magnetic sensor constitutes a part of the support wall. Features.
Thereby, the structure of the part which supports the peripheral part of a partition is simplified, and the whole is made compact.

The invention according to claim 5 is the seat belt device according to any one of claims 2 to 4, wherein the seat belt device is disposed at a position opposite to the winding spring across the magnetic rotating body in the cover, A sub cover (for example, a sub cover 23 in an embodiment described later) supporting the magnetic sensor is provided.
As a result, the winding spring, the partition, the magnetic rotating body, etc. are assembled in the cover, the magnetic sensor is attached to the sub cover, and the rotation detecting means and the winding spring are unitized by assembling the sub cover to the cover. Will come to be.

The invention according to claim 6 is the seat belt device according to any one of claims 1 to 5, wherein a sliding member having an excellent sliding property on a surface of the partition facing the winding spring. (For example, a hard resin in an embodiment described later), and the surface facing the rotation detecting means is configured by a magnetic shielding member (for example, a metal in an embodiment described later) having excellent magnetic shielding properties. To do.
Thereby, the surface of the partition facing the winding spring is improved in slidability, and the surface facing the rotation detecting means is improved in magnetic shielding.

According to a seventh aspect of the present invention, in the seat belt device according to any one of the first to sixth aspects, a power transmission unit (for example, a magnetic material) made of a magnetic material on a side facing the partition wall with the rotation detection unit interposed therebetween. The power transmission unit 8) in the embodiment described later is arranged.
Thereby, the partition and the opposite side surface of the rotation detecting means are magnetically shielded by the power transmission unit.

  According to the first aspect of the present invention, the partition provided between the rotation detecting means and the winding spring can prevent scattering of grease, wear powder, and the like from the winding spring side to the rotation detecting means side. In addition, since the partition walls are made of a magnetic material, magnetic noise can be prevented from entering from the winding spring side to the rotation detecting means side.

  According to the second aspect of the present invention, since the rotation detection means and the winding spring are partitioned into separate spaces in the cover, the penetration of grease, wear powder, etc. from the winding spring to the rotation detection means side can be ensured. Can be prevented.

  According to the third aspect of the invention, since the peripheral edge of the partition wall is supported from the rotation detecting means side by the support wall, leakage of grease and the like from the peripheral edge of the partition wall can be reliably prevented.

  According to the invention described in claim 4, since the structure of the portion supporting the peripheral edge of the partition wall is simplified, the cover covering the winding spring and the rotation detecting means is avoided from being enlarged, and the entire apparatus is made compact. Can be achieved.

  According to the fifth aspect of the present invention, the winding spring, the partition wall, the magnetic rotating body, and the like are assembled in the cover, the magnetic sensor is attached to the sub cover, and the sub cover is assembled to the cover to detect the rotation. Since the means and the take-up spring are easily unitized, the manufacturing cost can be reduced by facilitating manufacture and assembly.

  According to the sixth aspect of the present invention, the surface of the partition wall facing the winding spring is constituted by the sliding member, and the surface facing the rotation detecting means is constituted by the magnetic shielding member. It is possible to reduce the resistance and improve the magnetic shielding property against the rotation detecting means.

  According to the seventh aspect of the invention, since the power transmission unit magnetically shields the partition wall and the opposite side surface of the rotation detection means, it is possible to more reliably prevent magnetic noise from entering the rotation detection means from the outside. Become.

Embodiments of the present invention will be described below with reference to the drawings.
First, the first embodiment shown in FIGS. 1 to 6 will be described.
FIG. 1 shows a schematic configuration of a retractor 2 of a seat belt device 1 according to the present invention and a cross-section of a main part thereof, and FIG. 2 shows an exploded state of the retractor 2. In the retractor 2, as shown in these drawings, the belt reel 4 around which the webbing 3 (see FIG. 1) is wound is rotatably supported by the retractor frame 5, and the shaft 4 a of the belt reel 4 is connected to the retractor frame 5. It protrudes to the outside. 2 is a webbing guide portion for guiding the webbing 3 pulled out from the belt reel 4, and 7 is a rotational force applied to the belt reel 4 by the thrust of explosives when a collision impact is input. This is an explosive pretensioner mechanism that pulls in the webbing 3 instantly. In the following description, unless otherwise specified, the direction in which the shaft 4a of the belt reel 4 protrudes from the retractor frame 5 is referred to as the front, and the direction in which the webbing 3 is pulled out via the webbing guide 6 (upward in FIG. 2). Is referred to as the upper side.

  The shaft 4a of the belt reel 4 is connected to a motor 9 via a power transmission unit 8 including a power connection / disconnection clutch and a gear mechanism (not shown). The power transmission unit 8 is provided with an output shaft 10 that is coaxially connected to the shaft 4 a of the belt reel 4, and the output shaft 10 projects forward. The clutch in the power transmission unit 8 connects the motor 9 and the output shaft 10 (belt reel 4) only when the motor 9 is driven, and the motor 9 and the output shaft when the motor 9 is not driven. 10 (belt reel 4) is disconnected. The casing 8a of the power transmission unit 8 that houses the clutch and gear mechanism is formed of a magnetic material such as metal.

  A disc-shaped rotor (magnetic rotor) 11 having a magnetic ring 11 a on the outer periphery is connected to the front end portion of the output shaft 10, and a connecting shaft 12 projects forward at the axial center position of the rotor 11. ing. The magnetic ring 11a is magnetized so that different magnetic poles appear alternately along the circumferential direction, and the magnetism differs depending on the position in the circumferential direction. A pair of Hall elements 13A and 13B (magnetic sensors) spaced apart in the circumferential direction are arranged in close contact with each other on the outer peripheral side of the rotor 11, and the rotor 11 and the Hall elements 13A and 13B are disposed in the belt reel 4 The rotation detecting means 14 for detecting the rotation state of the motor is configured. The rotation detecting means 14 will be described in detail later.

  Further, a winding spring 15 for urging the belt reel 4 in the webbing winding direction is coupled to the connecting shaft 12 integral with the rotor 11. The winding spring 15 is constituted by a spring, and its inner peripheral end is coupled to the connecting shaft 12, while its outer peripheral end is coupled to the inner wall of the front cover 16 (cover) of the retractor 2. The front cover 16 is integrally coupled to the retractor frame 5. A shaft hole 17 is formed at the tip of the connecting shaft 12, and a guide protrusion 18 projecting from the front cover 16 is inserted into the shaft hole 17.

  The front cover 16 is integrally formed of a resin material and has a bottomed cylindrical spring accommodating portion 16a in which the take-up spring 15 is accommodated, coaxial with the spring accommodating portion 16a, and more than the spring accommodating portion 16a. A large-diameter cylindrical portion 16b formed to have a large diameter and a substantially rectangular sensor housing portion 16c connected to the lower end of the large-diameter cylindrical portion 16b are provided. The large-diameter cylindrical portion 16b accommodates the rotor 11 of the rotation detecting means 14, and the sensor accommodating portion 16c accommodates a substrate 19 (see FIG. 3) on which the Hall elements 13A and 13B are mounted.

  Between the spring accommodating portion 16a of the front cover 16 and the large diameter cylindrical portion 16b, a substantially disc-shaped partition wall 20 having a through hole 20a through which the connecting shaft 12 is inserted is disposed, and the inside of the front cover 16 is The partition 20 is divided into a spring housing space 21 on the bottom side and a rotor housing space 22 on the opening side. As shown in FIG. 2, a pair of support protrusions 20b and 20b are provided on the outer peripheral edge of the partition wall 20, and these support protrusions 20b and 20b are fitted into positioning grooves (not shown) on the peripheral wall of the large-diameter cylindrical portion 16b. It is like that. The positioning groove is formed up to a position reaching the boundary position between the spring accommodating portion 16a and the large-diameter cylindrical portion 16b, and the partition wall 20 is brought into contact with the terminal end portion of the positioning groove by contacting the support protrusions 20b and 20b. It is designed to be positioned inside. In the case of this embodiment, the whole partition 20 is formed of a magnetic shielding member such as metal.

  Further, after setting the winding spring 15, the partition wall 20, the rotor 10, etc. in the front cover 16, a sub cover 23 that is slightly smaller than the front cover 16 is fitted in a lid shape. . At this time, the spring accommodating space 21 is filled with grease for lubricating the winding spring 15. In this embodiment, the sub cover 23 is formed of the same resin material as that of the front cover 16, and is fixed to the front cover 16 by screws or the like. Further, an opening 30 for connecting the output shaft 10 of the power transmission unit 8 to the rotor 11 is provided in the bottom wall 23 a of the sub cover 23.

  As shown in FIGS. 3 and 4, the sub-cover 23 has a substantially cylindrical arc wall 23b (support wall) fitted to the large-diameter cylindrical portion 16b of the front cover 16, and both ends of the arc wall 23b. A substantially U-shaped rectangular wall 23c that is continuously provided and fitted into the sensor accommodating portion 16c of the front cover 16, and a sensor on which the substrate 19 on which the Hall elements 13A and 13B are mounted is arranged inside the rectangular wall 23c. An installation space 24 (see FIG. 4) is secured. The substrate 19 is held in a resin-made holding case 25 having a substantially arc shape as a whole. The holding case 25 is disposed in a sensor installation space 24 in the sub-cover 23 and protrudes from the sub-cover 23. It is locked by the pawls 26, 26.

  The holding case 25 is open on the side facing the bottom of the front cover 16, and in the state assembled to the front cover 16, the arc wall 25 a (support wall) facing the outer peripheral edge of the rotor 11 is the arc of the sub cover 23. A circular wall is formed together with the wall 23b. The front end surfaces of the arc walls 23b and 25a come into contact with the outer peripheral edge of the partition wall 20 from the rotor accommodating space 22 side in a state where the sub cover 23 is fitted and fixed to the front cover 16. .

  In the case of the seat belt device 1, the winding spring 15, the partition wall 20, the rotor 10 and the like are set in the front cover 16, and the sub cover 23 is attached to the opening side of the front cover 16 together with the holding case 25. The thing constitutes a cover unit 32 and is finally integrated with the power transmission unit 8 and the retractor frame 5 by bolt fastening or the like.

  Here, the rotation detection means 14 will be described with reference to FIGS. 5 and 6. The pair of Hall elements 13A and 13B of the rotation detection means 14 are connected to the controller 27 (FIG. 1) via a sensor circuit (not shown) for signal processing. , Refer to FIG. 5), and a pulse signal corresponding to the magnetic change detected by each Hall element 13 </ b> A, 13 </ b> B is output to the controller 27. The A-phase and B-phase pulse signals inputted from the hall elements 13A and 13B to the controller 27 are used as feedback signals for driving the motor 9 in the controller 27. Specifically, the controller 27 detects the amount of rotation of the belt reel 4 (the amount of webbing 3 pulled out) by counting the pulse signals of each phase of A phase and B phase. The rotation direction of the belt reel 4 is detected by comparing the rising edges of the waveforms of the two pulse signals (see FIG. 6).

  In the case of the seat belt device 1, the motor 9 is turned off when the webbing 3 is worn by the occupant or during normal running, and when the non-wearing is detected by releasing the buckle or the like, the motor 9 is appropriately turned on to reach the storage position. The webbing 3 is wound up. At this time, the pull-out amount and the moving direction of the webbing 3 are detected by the rotation detecting means 14 described above, and the motor 9 is controlled based on the detection result.

  In this seat belt device 1, the winding spring 15 in the cover unit 32 and the rotation detecting means 14 are partitioned by the partition wall 20, so that grease and wear from the winding spring 15 side to the rotation detecting means 14 side. Scattering of powder or the like can be reliably prevented by the partition wall 20. In the seat belt device 1, since the entire partition wall 20 is made of a magnetic material, the partition wall 20 can prevent magnetic noise from entering from the winding spring 15 side to the rotation detecting means 14 side. Therefore, even though the front cover 16 is made of a resin material that is lightweight and has a high degree of freedom of modeling, it is possible to reliably prevent a decrease in detection accuracy due to magnetic noise.

  In the seat belt device 1, the partition wall 20 and the rotation detection means 14 are accommodated in a common front cover 16, and the front cover 16 is divided into a spring accommodation space 21 and a rotor accommodation space 22. Therefore, it is possible to more reliably prevent grease and wear powder from entering from the take-up spring 15 to the rotation detecting means 14 side.

  In particular, in the seat belt device 1 of this embodiment, the outer peripheral edge of the partition wall 20 is pressed from the rotor housing space 22 side by the sub-cover 23 and the arc walls 23b and 25a of the holding case 25. The arc walls 23b and 25a are advantageous in that the peripheral edge of the partition wall 20 is prevented from warping and leakage of grease and the like from the peripheral edge can be more reliably prevented.

  It is conceivable that the wall that presses the peripheral edge of the partition wall 20 is formed in a circular shape in the sub-cover 23. However, as in this embodiment, arc walls 23b and 25a are formed in the sub-cover 23 and the holding case 25, respectively. When a circular wall that is continuous between the two is formed, the wall disposed between the Hall elements 13A and 13B and the rotor 11 becomes a single wall, so that the structure of the cover unit 32 is simplified. , Thereby reducing the size and weight, and further improving the detection accuracy of the rotation detecting means 14.

Further, in the seat belt device 1 of this embodiment, the winding spring 15, the partition wall 20, the rotor 11 and the like are assembled in the front cover 16, the holding case 25 is attached to the sub cover 23, and the sub cover 23 is attached to the front cover 16. Since it is structured to be fitted and fixed to the opening side of the part cover 16, the whole can be handled as the cover unit 32, and there is an advantage that manufacture and assembly are easy.
Further, in the case of this embodiment, by replacing only the cover unit 23 portion, the seat belt device 1 having the rotation detecting means 14 and the seat belt device not having the rotation detecting means 14 can be easily made separately. Since many parts can be shared by seat belt apparatuses of different specifications, there is also an advantage that the manufacturing cost can be reduced.

  In the seat belt device 1 of this embodiment, the casing 8a is formed of metal (magnetic material) on the back side of the rotation detecting means 14 sandwiching the sub cover 23 in a state where the cover unit 32 is attached to the retractor frame 5. Since the power transmission unit 8 is arranged, the power transmission unit 8 can prevent magnetic noise from entering the rotation detection means 14 from the sub-cover 23 side. Therefore, in this seat belt device 1, in combination with the magnetic shielding effect by the partition wall 20, magnetic noise can be reliably prevented from entering, and the detection accuracy by the rotation detecting means 14 can be further improved.

FIG. 7 shows a second embodiment of the present invention.
The seat belt device 101 of this embodiment has a basic configuration substantially the same as that of the first embodiment, but includes a partition 120 that divides the inside of the front cover 16 into a spring accommodating space 21 and a rotor accommodating space 22. The configuration is different. In the first embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
In the case of this embodiment, the partition wall 120 is not entirely formed of a magnetic shielding member such as metal, but only one surface facing the rotation detecting means 14 is formed of a magnetic shielding member such as metal and is wound up. The other surface facing the spring 15 is formed of a sliding member such as a hard resin having high slidability. In FIG. 7, the magnetic shielding member layer is indicated by symbol a, and the sliding member layer is indicated by symbol b.

  The seat belt device 101 of this embodiment can basically obtain the same effects as those of the first embodiment described above, but further, the surface of the partition wall 120 facing the winding spring 15 is made of a hard resin. Since the surface facing the rotation detecting means 14 is constituted by a magnetic shielding member such as metal, the sliding resistance of the winding spring 15 is reduced and the magnetic shielding property against the rotation detecting means 14 is provided. Can be improved at the same time.

  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 embodiment, the rotation detecting means 14 is configured by the rotor 11 and the pair of Hall elements 13A and 13B alternately magnetized with different magnetic poles along the circumferential direction. If it is a sensor, it is also possible to use magnetic sensors other than Hall element 13A, 13B. Further, the rotor may not be arranged with different magnetic poles alternately along the circumferential direction, but may change the strength of the magnetic force along the circumferential direction.

The 1st Embodiment of this invention is shown, and the longitudinal cross-sectional view of the principal part of a retractor. The disassembled perspective view of the retractor of the embodiment. Removed the retractor cover of the same embodiment The disassembled perspective view of the sub cover and holding case of the retractor of the embodiment. The schematic block diagram of the rotation detection means of the embodiment. The figure which shows the signal waveform of the rotation detection means of the embodiment. The 2nd Embodiment of this invention is shown and the expanded sectional view of the principal part of a retractor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 ... Seat belt apparatus 3 ... Webbing 4 ... Belt reel 8 ... Power transmission unit 11 ... Rotor (magnetic rotating body)
12 ... Connecting shaft (shaft)
13A, 13B ... Hall element (magnetic sensor)
DESCRIPTION OF SYMBOLS 14 ... Rotation detection means 15 ... Winding spring 16 ... Front cover (cover)
20, 120 ... partition wall 23 ... sub-cover 23b ... arc wall (support wall)
25 ... Holding case 25a ... Arc wall (support wall)

Claims (7)

A belt reel on which the webbing is wound and the webbing is fed and unwound according to the rotation;
Rotation detection means for detecting the rotation state of the belt reel;
A winding spring that urges the belt reel to rotate in the direction of winding the webbing;
With
The rotation detecting means rotates in conjunction with the belt reel and has different magnetic properties according to the circumferential position, and a magnetic sensor that detects a magnetic change according to the rotational state of the magnetic rotating member. Configured,
In the seat belt device, one end of the winding spring is connected to a shaft that rotates integrally with the magnetic rotating body,
A seat belt device comprising a partition made of a magnetic material between the rotation detecting means and the winding spring.   The seat belt device according to claim 1, wherein the rotation detecting means and the partition are housed in a common cover.   The seat belt device according to claim 2, wherein a support wall is provided in the cover so as to come into contact with the peripheral edge of the partition wall from the rotation detecting means side.   The seat belt device according to claim 3, wherein a holding case of the magnetic sensor constitutes a part of the support wall.   5. The apparatus according to claim 2, further comprising a sub-cover that is disposed at a position opposite to the winding spring across the magnetic rotating body in the cover and supports the magnetic sensor. The seat belt device according to the description.   Of the partition wall, the surface facing the winding spring is constituted by a sliding member having excellent slidability, and the surface facing the rotation detecting means is constituted by a magnetic shielding member having excellent magnetic shielding properties. The seatbelt device according to any one of claims 1 to 5, wherein the seatbelt device is provided.   The seat belt device according to any one of claims 1 to 6, wherein a power transmission unit made of a magnetic material is disposed on a side facing the partition wall with the rotation detection unit interposed therebetween.

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