JP6773468B2 - Seat belt retractor - Google Patents

Description

The present invention relates to a seatbelt retractor.

Conventionally, a seatbelt retractor including a spool for winding a seatbelt, a spiral spring for urging the spool in the winding direction of the seatbelt, and a spring case for accommodating the spiral spring is known (for example, a patent). See Document 1).

Japanese Unexamined Patent Publication No. 2011-157043

In the seatbelt retractor, the terminal portion (inner terminal portion) inside the spiral spring in the spiral direction is connected to the rotation axis of the spool, and the terminal portion (outer terminal portion) outside in the spiral direction of the spiral spring is the spring case. It is connected to the outer periphery.

However, if the force for further winding the spiral spring in the wound state in which the wound portion is deviated to the inside of the spring case is further increased, an excessive load may be applied to the outer terminal portion of the spiral spring. Similarly, if the force for further relaxing (releasing) the spiral spring in the relaxed state (released state) in which the wound portion is biased to the outside of the spring case is strengthened, an excessive load may be applied to the inner terminal portion of the spiral spring. ..

Therefore, one aspect of the present disclosure is to provide a seatbelt retractor capable of reducing an excessive load entering the terminal portion of the spiral spring.

In order to achieve the above object, in the first aspect of the present disclosure,
The spool that winds up the seat belt and
A spiral spring that urges the spool in the winding direction of the seat belt, and
A spring case rotatably provided around the rotation axis of the spool and accommodating the spiral spring,
It is equipped with a ratchet that rotates integrally with the rotating shaft and a connecting portion that can be engaged .
The spiral spring has an inner terminal portion connected to the rotating shaft and an outer terminal portion connected to the outer peripheral portion of the spring case.
The connecting portion is a Paul having a pressed portion pushed toward the inside of the spring case by an outer portion of the spiral spring and a claw portion capable of engaging with the outer teeth of the ratchet.
The poul is rotated around a turning shaft whose position is fixed to the bottom wall of the spring case by pushing the pressed portion toward the inside of the spring case to the outer portion, and the claw portion. Engages with the ratchet to provide a seatbelt retractor that connects the rotating shaft to the spring case.

According to the first aspect, when the force for further winding the spiral spring in the wound state in which the wound portion is biased to the inside of the spring case is increased, the force for bringing the outer portion of the spiral spring toward the inside of the spring case is increased. When the force that pulls the outer portion of the spiral spring toward the inside of the spring case is strengthened, the connecting portion is pushed toward the inside of the spring case by the outer portion, so that the rotating shaft and the spring case are brought together. It is connected by the connecting portion. By connecting the rotating shaft and the spring case, the rotating shaft and the spring case rotate integrally in the same direction, so that it is possible to suppress an increase in the force for further winding the spiral spring. Therefore, since the force for further winding up the spiral spring is suppressed, an excessive load entering the outer terminal portion of the spiral spring can be reduced.

According to the aspect of the present disclosure, it is possible to reduce an excessive load entering the terminal portion of the spiral spring.

It is a figure which shows an example of the structure of a seat belt system. It is a figure which shows typically the 1st example of the structure of a seatbelt retractor. It is a figure which shows an example of the form of the spiral spring in a relaxed state in which the winding part is deviated to the outside of a spring case. It is a figure which shows an example of the positional relationship between a ratchet and a Paul in a relaxed state in which a wound part of a spiral spring is deviated to the outside of a spring case. It is a figure which shows an example of the form of the spiral spring in the wound state in which the wound portion is deviated to the inside of the spring case. It is a figure which shows an example of the positional relationship between a ratchet and a Paul in a wound state in which the winding part of a spiral spring is deviated to the inside of a spring case. It is a figure which shows typically the 2nd example of the structure of a seatbelt retractor. It is a figure which shows an example of the form of the spiral spring in the wound state in which the wound portion is deviated to the inside of the spring case. It is a figure which shows an example of the positional relationship between a ratchet and a Paul in a wound state in which the winding part of a spiral spring is deviated to the inside of a spring case. It is a figure which shows an example of the form of the spiral spring in a relaxed state in which the winding part is deviated to the outside of a spring case. It is a figure which shows an example of the positional relationship between a ratchet and a Paul in a relaxed state in which a wound part of a spiral spring is deviated to the outside of a spring case. It is a perspective view which shows an example of the structure of the seat belt retractor. It is a front view which shows an example of the structure of a seat belt retractor. It is a side view which shows an example of the structure of a seatbelt retractor.

Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings.

FIG. 1 is a diagram showing an example of the configuration of the seatbelt system 1 according to the embodiment. The seatbelt system 1 is an example of a system mounted on a vehicle. The seatbelt system 1 includes, for example, a seatbelt 4, a retractor 3, a shoulder anchor 6, a tongue 7, a buckle 8, and an ECU (Electronic Control Unit) 100.

The seat belt 4 is an example of a webbing that restrains an occupant 11 sitting on a seat 2 of a vehicle, and is a band-shaped member that is retractably wound up by a retractor 3. The belt anchor 5 at the tip of the seat belt 4 is fixed to the floor of the vehicle body or the seat 2.

The retractor 3 is an example of a winding device that enables the seatbelt 4 to be wound or pulled out. Restrict being withdrawn from. The retractor 3 is fixed to the seat 2 or the vehicle body in the vicinity of the seat 2. The retractor 3 is an example of a seatbelt retractor.

The retractor 3 winds the seat belt 4 on the spool by the power of the motor. Before a vehicle collision, the retractor 3 operates a motor based on a signal from a sensor such as a millimeter-wave radar to wind the seatbelt 4 on a spool, applies pretension to the seatbelt 4, and restrains an occupant by the seatbelt 4. To do it quickly. Further, the retractor 3 operates a motor when the engagement between the tongue 7 and the buckle 8 is released, and winds up the seat belt 4 with a spool. Further, the retractor 3 operates a motor to adjust the tension of the seatbelt 4 according to the driving situation (vehicle condition), thereby restraining the occupant by the seatbelt 4 and comfort when the seatbelt 4 is fastened. To improve each.

The state of the vehicle is, for example, whether or not the seatbelt 4 is pulled out, whether or not the occupant 11 is present, the running speed of the vehicle, the acceleration of the vehicle, the steering operation, the accelerator operation, the brake operation, the operation of the buckle 8, the door operation, and the occupant's operation. It refers to a state that represents the operation input of a possible in-vehicle selection switch.

The shoulder anchor 6 is an example of a belt insertion tool through which the seat belt 4 is inserted, and is a member that guides the seat belt 4 pulled out from the retractor 3 toward the shoulder portion of the occupant 11.

The tongue 7 is an example of a belt insertion tool through which the seat belt 4 is inserted, and is a component slidably attached to the seat belt 4 guided by the shoulder anchor 6.

The buckle 8 is a component to which the tongue 7 is detachably connected, and is fixed to, for example, the floor or the seat 2 of the vehicle body.

With the tongue 7 engaged to the buckle 8, the portion of the seatbelt 4 between the shoulder anchor 6 and the tongue 7 is the shoulder belt portion 9 that restrains the chest and shoulders of the occupant 11. With the tongue 7 engaged to the buckle 8, the portion of the seat belt 4 between the belt anchor 5 and the tongue 7 is the lap belt portion 10 that restrains the waist portion of the occupant 11.

The ECU 100 is an example of a control device connected to the retractor 3 via one or a plurality of wire harnesses 101 so as to be able to communicate with the retractor 3.

<First Embodiment>
FIG. 2 is a diagram schematically showing an example of the configuration of the retractor 3C. The retractor 3C is an example of the retractor 3 shown in FIG. The retractor 3C includes a base frame 17, a spool 20, and a spring unit 74. Note that FIG. 2 shows a partial cross-sectional shape of the spring unit 74.

The spool 20 is rotatably supported by the base frame 17 and winds up the seat belt 4. The spool 20 is a rotating member that winds up the seat belt 4. The rotating shaft of the spool 20 includes a shaft 20a and a bush 31 fixed to one end of the shaft 20a.

The bush 31 has a cylindrical boss 26 and a flange-shaped ratchet 27. The boss 26 and the ratchet 27 are integrally formed. The shaft 20a penetrates the through hole formed in the central portion of the boss 26 and the through hole formed in the central portion of the ratchet 27. Both the boss 26 and the ratchet 27 are non-rotatably fixed to the shaft 20a.

The spring unit 74 has a bush 31, a spiral spring 22, a spring case 33, a Paul 36, and a unit cover 30.

The spiral spring 22 is an example of an elastic body that urges the spool 20 in the winding direction of the seat belt 4. The spiral spring 22 has an inner terminal portion connected to the boss 26 of the bush 31 integrally rotatably attached to the spool 20, and an outer terminal portion connected to the outer peripheral wall 28 of the spring case 33, and the spool 20 has a spool 20. Is always urged in the winding direction of the seat belt 4.

The spring case 33 is rotatably provided with respect to the base frame 17 about the rotation axis of the spool 20, and accommodates the spiral spring 22. The spring case 33 has a circular bottom wall 29 and an outer peripheral wall 28 protruding from the outer peripheral edge of the bottom wall 29 in the normal direction of the bottom wall 29. A through hole through which the boss 26 penetrates is formed in the central portion of the bottom wall 29. The spring case 33 is rotatably arranged around the boss 26 with respect to the bush 31.

The spring case 33 accommodates the ratchet 27 in the accommodating portion on the spool 20 side with respect to the bottom wall 29, and accommodates the spiral spring 22 in the accommodating portion on the opposite side of the bottom wall 29 from the spool 20.

The unit cover 30 covers the ratchet 27 and the spiral spring 22 housed in the spring case 33 together with the spring case 33. The unit cover 30 has a bearing that supports the shaft 20a.

FIG. 3 is a diagram showing an example of the form of the spiral spring 22 in a relaxed state in which the wound portion is deviated to the outside of the spring case 33. FIG. 3 shows a form in which the spring case 33 accommodates the spiral spring 22 transparently and schematically with the arrow A shown in FIG.

The spiral spring 22 has an inner terminal portion 22a connected to a boss 26 fixed to the shaft 20a so as not to rotate, and an outer terminal portion 22b connected to a hook wall 37 located on the outer peripheral portion of the spring case 33. Have. The inner terminal portion 22a is an example of the terminal portion inside the spiral spring 22 in the spiral direction, and the outer terminal portion 22b is an example of the terminal portion outside the spiral spring 22 in the spiral direction. The hook wall 37 is an example of a hook portion on which the outer terminal portion 22b is hooked.

The inner terminal portion 22a is connected to the boss 26, for example, by being hooked on the hook groove 31a formed in the boss 26. The outer terminal portion 22b is connected to the hook wall 37, for example, by being hooked on the hook wall 37. The direction in which the outer terminal portion 22b is folded back at the hook wall 37 is opposite to the direction in which the inner terminal portion 22a is folded back at the hook groove 31a. The hook wall 37 is an example of the outer peripheral portion of the spring case 33. The hook wall 37 may be a part of the outer peripheral wall 28 of the spring case 33, or may be a part different from the outer peripheral wall 28.

FIG. 4 is a diagram showing an example of the positional relationship between the ratchet 27 and the Paul 36 in a relaxed state (that is, the state shown in FIG. 3) in which the wound portion of the spiral spring 22 is biased to the outside of the spring case 33. FIG. 4 shows a form in which the spring case 33 accommodates the ratchet 27 and the claw portion 35 of the Paul 36 in a transparent and schematic manner with the arrow A shown in FIG.

As shown in FIGS. 3 and 4, the Paul 36 has a hook wall 37 and a claw portion 35, and is provided on the spring case 33. The Paul 36 is an example of a connecting portion that connects the rotating shaft of the spool and the spring case by being pushed toward the inside of the spring case by the outer portion of the spiral spring. The hook wall 37 is an example of a pressed portion that is pushed toward the inside of the spring case 33 by the outer portion of the spiral spring 22. The claw portion 35 is a portion capable of engaging with the external teeth 27a of the ratchet 27 that rotates integrally with the shaft 20a and the boss 26. The Paul 36 turns around a turning shaft 34 whose position is fixed to the bottom wall 29. The turning shaft 34 is provided on the bottom wall 29 so as to extend at a right angle to the bottom wall 29. FIG. 2 illustrates a form in which the turning shaft 34 penetrates the bottom wall 29.

FIG. 5 is a diagram showing an example of the form of the spiral spring 22 in the wound state in which the wound portion is deviated to the inside of the spring case 33. FIG. 5 shows the form in which the spring case 33 accommodates the spiral spring 22 transparently and schematically in the arrow A shown in FIG. FIG. 6 is a diagram showing an example of the positional relationship between the ratchet 27 and the Paul 36 in a wound state in which the wound portion of the spiral spring 22 is biased toward the inside of the spring case 33 (that is, the state shown in FIG. 5). FIG. 6 schematically shows a form in which the spring case 33 accommodates the ratchet 27 and the claw portion 35 of the Paul 36, as viewed by arrow A shown in FIG.

For example, when the spool 20 rotates in the pull-out direction of the seat belt 4 while the rotation of the spring case 33 is fixed, the shaft 20a rotates in the winding direction B of the spiral spring 22. As a result, the spiral spring 22 moves toward the inside of the spring case 33 so as to transition from the state of FIG. 3 to the state of FIG.

When the force for further winding the spiral spring 22 in the wound state (state in FIG. 5) in which the wound portion is biased to the inside of the spring case 33 is further strengthened, the force for pulling the outer portion of the spiral spring 22 toward the inside of the spring case 33 is strengthened. .. The outer portion of the spiral spring 22 includes an outer terminal portion 22b. When the force for pulling the outer portion of the spiral spring 22 toward the inside of the spring case 33 is increased, the hook wall 37 on which the outer portion is hooked is pushed toward the inside of the spring case 33 by the outer portion. When the hook wall 37 is pushed toward the inside of the spring case 33 by the outer portion, the hook wall 37 rotates around the turning shaft 34 toward the inside of the spring case 33 together with the claw portion 35, so that the claw portion 35 rotates toward the inside of the spring case 33. It meshes with the external teeth 27a of. As a result, the shaft 20a and the spring case 33 are connected by the Paul 36 via the ratchet 27 without the spiral spring 22.

In this way, when the shaft 20a and the spring case 33 are connected via the Paul 36, the shaft 20a and the spring case 33 rotate integrally in the same direction, so that the force for further winding the spiral spring 22 is strengthened. It can be suppressed. Therefore, it is possible to reduce an excessive load entering the outer terminal portion 22b of the spiral spring 22 in the wound state. As a result, for example, it is possible to prevent the outer terminal portion 22b from coming off the hook wall 37 due to an excessive load entering the outer terminal portion 22b.

The outer portion of the spiral spring 22 pushes the hook wall 37 toward the inside of the spring case 33. In the illustrated embodiment, the outermost winding portion of the spiral spring 22 among the outer portions of the spiral spring 22 pushes the hook wall 37 toward the inside of the spring case 33. The outermost winding portion of the spiral spring 22 pushes the hook wall 37 toward the inside of the spring case 33, so that the maximum spiral length for generating the urging force of the spiral spring 22 can be secured. However, among the outer portions of the spiral spring 22, a winding portion slightly inside from the outermost winding portion of the spiral spring 22 (for example, a winding portion one winding inside from the outermost winding portion) springs the hook wall 37. It may be pushed toward the inside of the case 33.

<Second embodiment>
FIG. 7 is a diagram schematically showing an example of the configuration of the retractor 3D. The retractor 3D is an example of the retractor 3 shown in FIG. The retractor 3D includes a base frame 17, a spool 20, and a spring unit 75. Note that FIG. 2 shows a partial cross-sectional shape of the spring unit 75.

The spool 20 is rotatably supported by the base frame 17 and winds up the seat belt 4. The spool 20 is a rotating member that winds up the seat belt 4. The rotating shaft of the spool 20 includes a shaft 20a and a bush 81 fixed to one end of the shaft 20a.

The bush 81 has a cylindrical boss 86 and a flange portion 85. The boss 86 and the flange portion 85 are integrally formed. The shaft 20a penetrates the through hole formed in the central portion of the boss 86 and the through hole formed in the central portion of the flange portion 85. Both the boss 86 and the flange portion 85 are non-rotatably fixed to the shaft 20a.

The spring unit 75 includes a bush 81, a spiral spring 22, a spring case 83, a Paul 96, and a unit cover 90.

The spiral spring 22 is an example of an elastic body that urges the spool 20 in the winding direction of the seat belt 4. The spiral spring 22 has an inner terminal portion connected to the boss 86 of the bush 81 integrally rotatably attached to the spool 20, and an outer terminal portion connected to the outer peripheral wall 88 of the spring case 83, and the spool 20 has a spool 20. Is always urged in the winding direction of the seat belt 4.

The spring case 83 is rotatably provided around the rotation axis of the spool 20 and accommodates the spiral spring 22. The spring case 83 has a circular bottom wall 89 and an outer peripheral wall 88 protruding from the outer peripheral edge of the bottom wall 89 in the normal direction of the bottom wall 89. A through hole through which the boss 86 penetrates is formed in the central portion of the bottom wall 89. The spring case 83 is rotatably arranged around the boss 86 with respect to the boss 86.

The spring case 83 accommodates the flange portion 85 in the accommodating portion on the spool 20 side with respect to the bottom wall 89, and accommodates the spiral spring 22 in the accommodating portion on the opposite side of the bottom wall 89 from the spool 20.

The unit cover 90 covers the flange portion 85 and the spiral spring 22 housed in the spring case 83 together with the spring case 83. The unit cover 90 has a bearing that supports the shaft 20a.

FIG. 8 is a diagram showing an example of the form of the spiral spring 22 in the wound state in which the wound portion is deviated to the inside of the spring case 83. FIG. 8 shows the form in which the spring case 83 accommodates the spiral spring 22 transparently and schematically by the arrow C shown in FIG.

The spiral spring 22 has an inner terminal portion 22a connected to a boss 86 fixed to the shaft 20a so as not to rotate, and an outer terminal portion 22b connected to a hook wall 98 located on the outer peripheral portion of the spring case 33. Have. The hook wall 98 is an example of a hook portion on which the outer terminal portion 22b is hooked.

The inner terminal portion 22a is connected to the boss 26, for example, by being hooked on the hook groove 81a formed in the boss 86. The outer terminal portion 22b is connected to the hook wall 98, for example, by being hooked on the hook wall 98. The direction in which the outer terminal portion 22b is folded back at the hook wall 98 is opposite to the direction in which the inner terminal portion 22a is folded back at the hook groove 81a. The hook wall 98 is an example of the outer peripheral portion of the spring case 33. The hook wall 98 may be a part of the outer peripheral wall 88 of the spring case 83, or may be a part different from the outer peripheral wall 88.

FIG. 9 is a diagram showing an example of the positional relationship between the ratchet 87 and Paul 96 in a wound state (that is, the state shown in FIG. 8) in which the wound portion of the spiral spring 22 is biased inward of the spring case 83. FIG. 9 shows a form in which the spring case 83 accommodates the flange portion 85 and the claw portion 95 of the Paul 96 in a transparent and schematic manner with the arrow C shown in FIG.

As shown in FIGS. 8 and 9, the Paul 96 has a hook pin 97 and a claw portion 95, and is provided on the flange portion 85. The Paul 96 is an example of a connecting portion that connects the rotating shaft of the spool and the spring case by being pushed toward the outside of the spring case by the inward portion of the spiral spring. The hook pin 97 is an example of a pressed portion that is pushed toward the outside of the spring case 83 by the inward portion of the spiral spring 22. The claw portion 95 is a portion capable of engaging with the internal teeth 87a of the ratchet 87 that rotates integrally with the spring case 83. The ratchet 87 is a portion formed on the outer peripheral wall 88 on the spool 20 side with respect to the bottom wall 89 of the spring case 83. The internal teeth 87a are formed on the inner surface of the outer peripheral wall 88.

The Paul 96 rotates around a rotation shaft 94 whose position is fixed to a flange portion 85 that rotates integrally with the shaft 20a and the boss 86. The turning shaft 94 is provided on the flange portion 85 so as to extend at a right angle to the flange portion 85. 7 and 8 illustrate a form in which the hook pin 97 penetrates the guide hole 89a formed in the bottom wall 89. The guide hole 89a has a curved hole shape.

FIG. 10 is a diagram showing an example of the form of the spiral spring 22 in a relaxed state in which the wound portion is deviated to the outside of the spring case 83. FIG. 10 shows the form in which the spring case 83 accommodates the spiral spring 22 transparently and schematically in the arrow C shown in FIG. FIG. 11 is a diagram showing an example of the positional relationship between the ratchet 87 and the Paul 96 in a relaxed state (that is, the state shown in FIG. 10) in which the wound portion of the spiral spring 22 is biased to the outside of the spring case 83. FIG. 11 shows a form in which the spring case 83 accommodates the flange portion 85 and the claw portion 95 of the Paul 96 transparently and schematically in the arrow C shown in FIG.

For example, when the spool 20 rotates in the winding direction of the seat belt 4 while the rotation of the spring case 83 is fixed, the shaft 20a rotates in the relaxation direction (release direction) E of the spiral spring 22. As a result, the spiral spring 22 moves toward the outside of the spring case 83 so as to transition from the state of FIG. 8 to the state of FIG.

When the force for further relaxing the spiral spring 22 in the relaxed state (state of FIG. 10) in which the wound portion is biased to the outside of the spring case 83 is further strengthened, the force for pulling the inward portion of the spiral spring 22 to the outside of the spring case 83 is increased. Strengthen. The inward portion of the spiral spring 22 includes an inner terminal portion 22a. When the force for pulling the inward portion of the spiral spring 22 toward the outside of the spring case 83 is increased, the hook pin 97 on which the inward portion is hooked is pushed toward the outside of the spring case 83 by the inward portion. When the hook pin 97 is pushed toward the outside of the spring case 83 by the inward portion, the hook pin 97 rotates around the turning shaft 94 toward the outside of the spring case 83 together with the claw portion 95, so that the claw portion 95 rotates toward the outside of the spring case 83. It meshes with the internal teeth 87a of the. As a result, the shaft 20a and the spring case 83 are connected by the Paul 96 via the ratchet 87 without the spiral spring 22.

In this way, when the shaft 20a and the spring case 83 are connected via the Paul 96, the shaft 20a and the spring case 83 rotate integrally in the same direction, so that the force for further relaxing the spiral spring 22 is strengthened. Can be suppressed. Therefore, it is possible to reduce an excessive load entering the inner terminal portion 22a of the spiral spring 22 in the relaxed state. As a result, for example, it is possible to prevent the inner terminal portion 22a from coming off the hook groove 81a due to an excessive load entering the inner terminal portion 22a.

The inward portion of the spiral spring 22 pushes the hook pin 97 toward the outside of the spring case 83. In the illustrated embodiment, the innermost winding portion of the spiral spring 22 among the inward portions of the spiral spring 22 pushes the hook pin 97 toward the outside of the spring case 83. The innermost winding portion of the spiral spring 22 pushes the hook pin 97 toward the outside of the spring case 83, so that the maximum spiral length for generating the urging force of the spiral spring 22 can be secured. However, among the inward portions of the spiral spring 22, the winding portion slightly outer from the innermost winding portion of the spiral spring 22 (for example, the winding portion one winding outer from the innermost winding portion) springs the hook pin 97. It may be pushed toward the outside of the case 83.

<Third embodiment>
FIG. 12 is a perspective view showing an example of the configuration of the retractor 3A. The retractor 3A is an example of the retractor 3 shown in FIG. In FIG. 12, the retractor 3A includes, for example, a base frame 17 and a spool 20 that is rotatably supported by the base frame 17 and winds up the seat belt 4.

FIG. 13 is a front view showing an example of the configuration of the retractor 3A. FIG. 14 is a side view showing an example of the configuration of the retractor 3A.

The retractor 3A includes a spool 20, a spiral spring 22, a spring case 33, a first rotation disc 38, a first rotation detection unit 40, a second rotation disc 58, and a second rotation detection unit 60. And a calculation unit 73, and a motor 24.

The spool 20 is a rotating member that winds up the seat belt 4. The rotating shaft of the spool 20 includes a shaft 20a and a bush 21 fixed to one end of the shaft 20a.

The spiral spring 22 has one end 22a connected to the rotation shaft of the spool 20 and the other end connected to the outer peripheral wall of the spring case 33, and has elasticity that urges the spool 20 in the winding direction of the seat belt 4. It is an example of the body. The spiral spring 22 has one end 22a connected to a bush 21 rotatably attached to the spool 20 to constantly urge the spool 20 in the winding direction of the seat belt 4. One end 22a of the spiral spring 22 is hooked in the hook groove 21a formed in the bush 21.

The spring case 33 has an outer peripheral wall to which the other end of the spiral spring 22 is connected, and accommodates the spiral spring 22 inside the outer peripheral wall. The spring case 33 is rotatably provided with respect to the base frame 17 about the rotation axis of the spool 20. That is, the spring case 33 is provided so as to be rotatable coaxially with the rotation axis of the spool 20. External teeth 33a are formed on the outer peripheral wall of the spring case 33.

The first rotating disc 38 is rotatably attached to the base frame 17. The first rotating disc 38 has an annular first magnet holding member 42 and a first magnet 41 that is integrally rotatable and annularly arranged on the first magnet holding member 42. There is. The annular first magnet 41 is formed by alternately arranging N-pole magnets 41a and S-pole magnets 41b in the circumferential direction of the first magnet 41. The magnetizing width of the N-pole magnet 41a is set to a predetermined first angular width in the circumferential direction of the first magnet 41, and the magnetizing width of the S-pole magnet 41b is the circumference of the first magnet 41. It is set to a predetermined second angle width in the direction. The second angular width may be the same as or different from the first angular width. The first magnet holding member 42 integrally has a tubular first transmitted gear 43 having external teeth 43a (see FIG. 14) arranged concentrically with the first magnet holding member 42. .. The first magnet 41 rotates coaxially with the rotation axis of the first transmitted gear 43 together with the first transmitted gear 43 as the first transmitted gear 43 rotates.

A transmission gear 44 is rotatably and concentrically attached to the shaft 20a of the rotating shaft of the spool 20 so as to be integrally rotatable with the shaft 20a. External teeth 44a are formed on the outer peripheral portion of the transmission gear 44. The external teeth 43a of the first transmission gear 43 mesh with the external teeth 44a of the transmission gear 44.

The first rotation detection unit 40 is an example of a rotation detection unit that detects the rotation of the spool 20. The first rotation detection unit 40 detects the rotation of the spool 20 by detecting the rotation of the first magnet 41, for example. The first rotation detection unit 40 includes, for example, a first magnetic detection unit 40a and a second magnetic detection unit 40b. The first magnetic detection unit 40a and the second magnetic detection unit 40b each detect magnetism that changes with the rotation of the first magnet 41. A Hall element can be mentioned as a specific example of the first magnetic detection unit 40a and the second magnetic detection unit 40b. The Hall element is an example of a semiconductor element that detects a magnetic change by the Hall effect.

When the spool 20 rotates in the pull-out direction of the seat belt 4, the transmission gear 44 that rotates integrally with the rotation shaft of the spool 20 rotates. When the transmission gear 44 rotates, the first transmitted gear 43 in which the external teeth 43a meshing with the external teeth 44a of the transmission gear 44 are formed rotates, so that the first magnet 41 of the first rotating disc 38 is rotated. Rotate. That is, when the spool 20 rotates in the pull-out direction of the seat belt 4, the first magnet 41 rotates in the rotation direction corresponding to the pull-out direction of the seat belt 4 in conjunction with the rotation of the spool 20.

When the first magnet 41 rotates, the first magnetic detection unit 40a and the second magnetic detection unit 40b detect the N-pole magnet 41a and the S-pole magnet 41b, respectively. Outputs a detection signal whose phase is inverted at. Further, since the arrangement position of the first magnetic detection unit 40a is different from the arrangement position of the second magnetic detection unit 40b, the phase of the detection signal output from the first magnetic detection unit 40a is the phase of the second magnetic detection. The phase of the detection signal output from the unit 40b is deviated by a predetermined amount.

The calculation unit 73 detects the rotation amount (rotation position) of the spool 20 by counting the number of phase inversions of the detection signals output from each of the first magnetic detection unit 40a and the second magnetic detection unit 40b. To do. Further, the calculation unit 73 rotates the spool 20 based on the phase shift between the detection signal output from the first magnetic detection unit 40a and the detection signal output from the second magnetic detection unit 40b. It is determined whether the direction is the pull-out direction of the seat belt 4 or the winding direction of the seat belt 4.

The second rotating disc 58 is rotatably attached to the base frame 17. The second rotating disc 58 has an annular second magnet holding member 62 and a second magnet 61 that is integrally rotatable and annularly arranged on the second magnet holding member 62. There is. The annular second magnet 61 is formed by alternately arranging N-pole magnets 61a and S-pole magnets 61b in the circumferential direction of the second magnet 61. The magnetizing width of the N-pole magnet 61a is set to a predetermined third angular width in the circumferential direction of the second magnet 61, and the magnetizing width of the S-pole magnet 61b is the circumference of the second magnet 61. It is set to a predetermined fourth angle width in the direction. The fourth angle width may be the same as or different from the third angle width. The second magnet holding member 62 integrally has a tubular second transmitted gear 63 having external teeth 63a arranged concentrically with the second magnet holding member 62. The second magnet 61 rotates coaxially with the rotation axis of the second transmitted gear 63 together with the second transmitted gear 63 as the second transmitted gear 63 rotates.

The external teeth 63a of the second transmitted gear 63 mesh with the external teeth 33a of the spring case 33.

The second rotation detection unit 60 is an example of a rotation detection unit that detects the rotation of the spring case 33. The second rotation detection unit 60 detects the rotation of the spring case 33 by detecting the rotation of the second magnet 61, for example. The second rotation detection unit 60 includes, for example, a third magnetic detection unit 60a and a fourth magnetic detection unit 60b. The third magnetic detection unit 60a and the fourth magnetic detection unit 60b each detect magnetism that changes with the rotation of the second magnet 61. A Hall element can be mentioned as a specific example of the third magnetic detection unit 60a and the fourth magnetic detection unit 60b. The Hall element is an example of a semiconductor element that detects a magnetic change by the Hall effect.

When the spring case 33 is rotated in the pull-out direction of the seat belt 4 by the drive of the motor 24, the second transmitted gear 63 in which the external teeth 63a meshing with the external teeth 33a of the spring case 33 is formed rotates. The rotation of the second transmitted gear 63 causes the second magnet 61 of the second rotating disc 58 to rotate. That is, when the spring case 33 rotates in the pull-out direction of the seat belt 4, the second magnet 61 rotates in the rotation direction corresponding to the pull-out direction of the seat belt 4 in conjunction with the rotation of the spring case 33.

When the second magnet 61 rotates, the third magnetic detection unit 60a and the fourth magnetic detection unit 60b detect the N-pole magnet 61a and the S-pole magnet 61b, respectively. Outputs a detection signal whose phase is inverted at. Further, since the arrangement position of the third magnetic detection unit 60a is different from the arrangement position of the fourth magnetic detection unit 60b, the phase of the detection signal output from the third magnetic detection unit 60a is the phase of the fourth magnetic detection. The phase of the detection signal output from the unit 60b is deviated by a predetermined amount.

The calculation unit 73 counts the number of phase inversions of the detection signals output from each of the third magnetic detection unit 60a and the fourth magnetic detection unit 60b, thereby counting the rotation amount (rotation position) of the spring case 33. Detect. Further, the calculation unit 73 of the spring case 33 is based on the phase shift between the detection signal output from the third magnetic detection unit 60a and the detection signal output from the fourth magnetic detection unit 60b. It is determined whether the rotation direction is the pull-out direction of the seat belt 4 or the winding direction of the seat belt 4.

The calculation unit 73 is the difference between the rotation amount of the spool 20 whose rotation is detected by the first rotation detection unit 40 and the rotation amount of the spring case 33 whose rotation is detected by the second rotation detection unit 60 (hereinafter, The difference D) is calculated, and the calculation result of the difference D is output. Specific examples of the calculation unit 73 include a microcomputer, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), and the like.

The ECU 100 (see FIG. 1) acquires the calculation result of the difference D obtained by the calculation unit 73 via the wire harness 101. The ECU 100 controls the drive of the motor 24 according to the acquired calculation result of the difference D.

When the ECU 100 controls the drive of the motor 24 in this way, the motor 24 rotates the spring case 33 according to the difference D. For example, as the difference D increases, the tension of the seat belt 4 changes (for example, increases). Therefore, when the motor 24 rotates the spring case 33 according to the difference D, the motor 24 can continuously and steplessly adjust the tension of the seat belt 4 with high accuracy.

The configurations of the first embodiment (FIGS. 2 to 6) and the second embodiment (FIGS. 7 to 11) can be applied to the third embodiment (FIGS. 12 to 14). For example, by connecting the shaft 20a and the spring case by a Paul, the motor 24 can directly rotate the spool 20 without the spiral spring 22. As a result, a tension larger than the tension that can be generated by the spiral spring 22 can be generated in the seat belt 4.

Although the seatbelt retractor has been described above according to the embodiment, the present invention is not limited to the above embodiment. Various modifications and improvements, such as combinations and substitutions with some or all of the other embodiments, are possible within the scope of the present invention.

1 Seat belt system 3A, 3C, 3D Retractor 17 Base frame 20 Spool 20a Shaft 21, 31, 81 Bush 21a, 31a, 81a Hook groove 22 Spiral spring 22a Inner terminal 22b Outer terminal 24 Motor 25 Worm 26,86 Boss 27 , 87 Ratchet 27a External teeth 28,88 Outer wall 29,89 Bottom wall 30,90 Unit cover 33,83 Spring case 33a External teeth 34,94 Rotating shaft 35,95 Claw 36,96 Paul 37 Hook wall 38 First Rotation disk 40 1st rotation detection unit 40a 1st magnetic detection unit 40b 2nd magnetic detection unit 41 1st magnet 41a, 61a N-pole magnet 41b, 61b S-pole magnet 42 1st magnet holding member 43 1st Transmission gear 43a, 63a External teeth 44 Transmission gear 58 Second rotation disk 60 Second rotation detection unit 60a Third magnetic detection unit 60b Fourth magnetic detection unit 61 Second magnet 62 Second magnet holding Member 63 Second transmitted gear 70, 71, 72 Board 74, 75 Spring unit 85 Flange portion 87a Internal tooth 89a Guide hole 97 Hook pin 98 Hook wall

Claims (2)

The spool that winds up the seat belt and
A spiral spring that urges the spool in the winding direction of the seat belt, and
A spring case rotatably provided around the rotation axis of the spool and accommodating the spiral spring, and a spring case.
It is equipped with a ratchet that rotates integrally with the rotating shaft and a connecting portion that can be engaged .
The spiral spring has an inner terminal portion connected to the rotating shaft and an outer terminal portion connected to the outer peripheral portion of the spring case.
The connecting portion is a Paul having a pressed portion pushed toward the inside of the spring case by an outer portion of the spiral spring and a claw portion capable of engaging with the outer teeth of the ratchet.
The poul is rotated around a turning shaft whose position is fixed to the bottom wall of the spring case by pushing the pressed portion toward the inside of the spring case to the outer portion, and the claw portion. A seatbelt retractor that connects the rotating shaft and the spring case by engaging with the ratchet . The seatbelt retractor according to claim 1, further comprising a motor for rotating the spring case.