Seat belt retractor

Abstract

Provided is a seatbelt retractor with which it is possible, using a simple configuration, to realize switching of twist torque by a torsion bar after a pretensioner stops operating. This seatbelt retractor 1 comprises a spindle 70, a pretensioner 20, a tread head 40, a torsion bar 50, and a lock ring 80. While the pretensioner 20 operates, rotation of the tread head 40 in a winding direction is transmitted to the spindle 70 via the torsion bar 50, whereby the lock ring 80 rotates in the winding direction together with the spindle 70. Moreover, after the pretensioner 20 stops operating, the rotation is hindered, the spindle 70 is permitted to rotate relative to the lock ring 80 in an extension direction of a belt due to a passenger load that is caught on the belt, and the torsion bar 50 is twisted due to the relative rotation of the spindle 70.

Description

Technical Field

[0001] The present disclosure relates to a seat belt retractor for a vehicle.

Background Art

[0002] During a vehicle collision, the injury suffered by the occupant increases as the collision progresses. In order to reduce such injuries suffered by the occupant, generally, the spindle assembly of the seat belt retractor instantaneously winds up the seat belt during a vehicle collision, effectively restrains the body of the occupant, and then is configured to pay out the seat belt in order to reduce the burden on the occupant's chest. In order to realize the switching between the winding and paying out of the seat belt by such a spindle assembly, a seat belt retractor employing a switching device is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, the switching device as disclosed in Patent Document 1 realizes the winding and paying out of the seat belt by the spindle assembly by moving a part of the configuration of the spindle assembly using the gas pressure generated by the ignition of the path switching gas generator. Such a switching device has a complicated configuration. Further, since it is necessary to dispose the switching device outside the spindle assembly, when the switching device is employed, the seat belt retractor becomes larger. As a result, the manufacturing cost of the seat belt retractor increases, and the degree of freedom in installing the seat belt retractor may decrease.

[0005] The present disclosure aims to provide a seat belt retractor that can switch the torsional torque by a torsion bar after the pretensioner has stopped operating, using a simple configuration. [Means for solving the problem]

[0006] A seat belt retractor according to one aspect of the present disclosure comprises a spindle around which a belt is wound, a pretensioner that operates to transmit a force to rotate the spindle in the belt winding direction to the spindle via a transmission path, a tread head provided in the transmission path and rotating in the winding direction in response to the force from the pretensioner, a torsion bar provided in the transmission path with one end fixed to the tread head and the other end fixed to the spindle, and a lock ring provided between the tread head and the spindle, wherein when the pretensioner is operated, the rotation of the tread head in the winding direction is transmitted to the spindle via the torsion bar, causing the lock ring to rotate together with the spindle in the winding direction, while after the operation of the pretensioner is stopped, the rotation is prevented, and the spindle is allowed to rotate relative to the lock ring in the belt unwinding direction due to the load of the occupant on the belt, causing the torsion bar to twist due to the relative rotation of the spindle.

[0007] In this embodiment, when the lock ring, which rotates in the winding direction together with the spindle when the pretensioner is activated, is prevented from rotating after the pretensioner stops, the torsion bar, which rotates together with the tread head when the pretensioner is activated, is twisted by the relative rotation of the spindle with respect to the lock ring after the pretensioner stops, and energy is absorbed. In this way, the torsional torque of the torsion bar can be easily adjusted by using the lock ring provided between the spindle and the tread head. [Effects of the Invention]

[0008] According to this disclosure, a seat belt retractor can be provided that enables switching of the torsional torque by the torsion bar after the pretensioner has stopped operating, using a simple configuration. [Brief explanation of the drawing]

[0009] [Figure 1] This is an exploded perspective view showing the configuration of a seat belt retractor according to the first embodiment. [Figure 2] This is a cross-sectional view showing the configuration of a seat belt retractor according to the first embodiment. [Figure 3] This is an exploded perspective view showing the spindle assembly of a seat belt retractor according to the first embodiment, viewed from one direction. [Figure 4] This is an exploded perspective view from another direction showing the spindle assembly of the seat belt retractor according to the first embodiment, viewed from another direction. [Figure 5A] This figure shows the state of Paul before the pretensioner of the seat belt retractor according to the first embodiment is activated. [Figure 5B] This figure shows the state of the pole when the pretensioner of the seat belt retractor is activated according to the first embodiment. [Figure 5C] This figure shows the state of Paul after the operation of the pretensioner of the seat belt retractor according to the first embodiment has stopped. [Figure 6] This figure shows the sliding movement of the sleeve of the seat belt retractor according to the first embodiment. [Figure 7A] This figure shows the state of the seat belt retractor before the spindle starts to extend and rotate according to the first embodiment. [Figure 7B] This figure shows the twist state of the first bar and the position of the sleeve when the spindle of the seat belt retractor according to the first embodiment is rotated 90 degrees in the unwinding direction. [Figure 7C]The figure which shows the torsion state of the 1st bar and the position of the sleeve when the spindle of the seatbelt retractor which concerns on 1st Embodiment rotates 135 degrees in the payout direction. [Figure 7D] The figure which shows the torsion state of the 1st bar and the position of the sleeve when the spindle of the seatbelt retractor which concerns on 1st Embodiment rotates 200 degrees in the payout direction. [Figure 7E] The figure which shows the torsion state of the 1st bar and the 2nd bar, the position of the sleeve when the spindle of the seatbelt retractor which concerns on 1st Embodiment rotates 720 degrees in the payout direction. [Figure 7F] The figure which shows the torsion state of the 1st bar and the 2nd bar, the position of the sleeve when the spindle of the seatbelt retractor which concerns on 1st Embodiment rotates 1080 degrees in the payout direction. [Figure 8] The exploded perspective view which shows the structure of the seatbelt retractor which concerns on 2nd Embodiment. [Figure 9] The sectional view which shows the structure of the seatbelt retractor which concerns on 2nd Embodiment. [Figure 10] The figure which shows the attachment state of the energy absorption member of the seatbelt retractor which concerns on 2nd Embodiment. [Figure 11A] The figure which shows the state of the pawl before the pretensioner of the seatbelt retractor which concerns on 3rd Embodiment operates. [Figure 11B] The figure which shows the state of the pawl when the pretensioner of the seatbelt retractor which concerns on 3rd Embodiment operates. [Figure 11C] The figure which shows the state of the pawl after the operation of the pretensioner of the seatbelt retractor which concerns on 3rd Embodiment stops.

The form for implementing the invention

[0010] Referring to the accompanying drawings, a retractor for a seat belt according to a preferred embodiment of the present disclosure will be described. In this document, the direction in which the seat belt is wound is defined as the "winding direction D1", and the direction in which the seat belt is unwound is defined as the "unwinding direction D2". Also, the time when the vehicle is about to collide and the time when the vehicle collides are collectively defined as "when the vehicle collides", and the state of the vehicle other than "when the vehicle collides" is defined as the "normal state". Further, the thrust direction in which the sleeve 60 described later moves along the rotation axis of the spindle 70 is defined as the "rotation axis direction" (see FIG. 1), the direction in which the sleeve 60 moves away from the spindle 70 is defined as the "separation direction" or the "first direction", and the direction in which the sleeve 60 approaches the spindle 70 is defined as the "second direction".

[0011] [First Embodiment] <Retractor 1 for Seat Belt> First, referring to FIGS. 1 to 5C, the configuration of the retractor 1 for a seat belt according to the first embodiment will be described.

[0012] As shown in FIGS. 1 and 2, the retractor 1 for a seat belt includes a spindle assembly 10 around which a seat belt (not shown) is wound, a pretensioner 20 that actuates the winding of the seat belt by the spindle assembly 10, and a frame 30 that supports the spindle assembly 10 and the pretensioner 20.

[0013] The retractor 1 for a seat belt also includes a winding spring device (not shown) that biases the spindle assembly 10 in the winding direction D1 of the seat belt, an acceleration sensor that detects the horizontal acceleration of the vehicle, and a locking mechanism that locks the unwinding operation of the seat belt according to the acceleration detected by the acceleration sensor.

[0014] (Spindle Assembly 10) The spindle assembly 10 is an example of a configuration that allows it to rotate in the winding direction D1 by the pretensioner 20 to wind up the seat belt, and then rotate in the unwinding direction D2 to unwind the seat belt due to the load of the occupant placed on the seat belt. The spindle assembly 10 is rotatably supported by the frame 30. Hereinafter, the rotation of the spindle assembly 10 in the winding direction D1 will be referred to as "winding rotation," and the rotation in the unwinding direction D2 will be referred to as "unwinding rotation."

[0015] Furthermore, the spindle assembly 10 is equipped with a stopping device (not shown). This stopping device is configured to stop the operation of the pretensioner 20 and to stop the rotation of the tread head 40 of the spindle assembly 10, which will be described later. Details of the spindle assembly 10 will be described later.

[0016] (Pretensioner 20) The pretensioner 20 is an example of a device that operates to transmit a force to rotate the spindle assembly 10 in the winding direction D1 to the spindle assembly 10 via a transmission path. Here, the transmission path is formed by a part of the configuration of the spindle assembly 10. As shown in Figures 1 and 2, the pretensioner 20 comprises a drive unit 21 that drives the winding rotation of the spindle assembly 10, and a drive cover 22 and a distance plate 23 that support the drive unit 21.

[0017] As shown in Figure 1, the drive unit 21 includes a pipe housing 24 attached to the frame 30, a gas generator 25, a spring 26, a piston 27, and a plurality of balls 28 as a mass body, all of which are provided inside the pipe housing 24, and a cap 29 for fixing the pipe housing 24.

[0018] The gas generator 25, piston 27, and cap 29 are configured to eject multiple balls 28 from the tube housing 24. The multiple balls 28 are configured to transmit the thrust from the piston 27 to the tread head 40 located in the transmission path of the spindle assembly 10, which will be described later. The spring 26 is configured to prevent the generation of abnormal noise due to rattling of the multiple balls 28 inside the tube housing 24 under normal conditions.

[0019] As shown in Figure 2, the drive cover 22 is configured to rotatably support one end of the tread head 40. As shown in Figure 2, one end face of the distance plate 23 is attached to the drive cover 22, and the other end face is fixed to the frame 30 so as to cover the pipe housing 24. In other words, the drive cover 22 is fixed to the frame 30 via the distance plate 23.

[0020] As shown in Figure 2, the space inside the assembly of the drive cover 22 and the distance plate 23 constitutes a space 200 for housing the tread head 40. The inner circumferential surface 210 of the space 200 and the pinion 410 of the tread head 40, which will be described later, constitute the movement path for the multiple balls 28 of the drive unit 21. The movement path is connected to the drive unit 21 via the open end 211 of the pipe housing 24.

[0021] (Frame 30) The frame 30 is fixed to the vehicle when the seat belt retractor 1 is installed on the vehicle. As shown in Figures 1 and 2, the frame 30 comprises a frame body 31 and a pole 32 provided on the frame body 31.

[0022] The frame body 31 is configured to fix the pretensioner 20 and to house the spindle assembly 10. The pole 32 is configured to restrict the rotation direction of the lock ring 80 of the spindle assembly 10, which will be described later.

[0023] As shown in Figures 1 and 5A, the Paul 32 includes a Paul body 321, a rotating shaft 322 that rotatably supports the Paul body 321, a spring device 323 that biases the Paul body 321 so as to press it against the lock ring 80 of the spindle assembly 10 (described later), and a Paul stopper 326. The Paul body 321 has a claw portion 324 and a flat portion 325.

[0024] The claw portion 324 is an example of an engagement portion provided on the frame 30 for engaging with the lock ring 80 of the spindle assembly 10, which will be described later. Before the pretensioner 20 is activated, the pawl 32 is fixed in a position where it does not engage with the ratchet teeth 83 of the lock ring 80, which will be described later, by the pawl stopper 326, as shown in Figure 5A. When the pretensioner 20 is activated and the spindle 70 rotates in the winding direction D1, the operation of the pretensioner 20 causes the pawl stopper 326 to move from the position shown in Figure 5A to the position shown in Figure 5B. As a result, the pawl 32 is rotated by the spring device 323 in a direction that engages with the ratchet teeth 83 of the lock ring 80, as shown in Figure 5C. Then, the contact between the flat portion 325 of the pawl 32 and the ratchet teeth 83 of the lock ring 80 allows the lock ring 80 and the spindle 70 to rotate in the winding direction D1. On the other hand, when the spindle 70 rotates in the payout direction D2, the pawl 32 engages with the ratchet teeth 83 of the lock ring 80, as shown in Figure 5C, preventing the lock ring 80 and the spindle 70 from rotating in the payout direction D2. In this way, the lock ring 80 is fixed to the frame 30 by the pawl 32.

[0025] During a vehicle collision, the pretensioner 20 activates. Specifically, the ignition of the gas generator 25 increases the gas pressure inside the tube housing 24, causing the ball 28 in the tube housing 24 to be pushed by the piston 27 and ejected from the open end 211 into the movement path. Once in the movement path, the ball 28 engages with the pinion 43 of the tread head 40 (described later), transmitting the thrust from the piston 27 to the transmission path where the tread head 40 is located, rotating the spindle assembly 10 in the winding direction D1 to wind up the seat belt. After the ejection of the multiple balls 28 stops, the pretensioner 20 stops operating. Simultaneously, the stopping device activates, stopping the rotation of the tread head 40. After the winding of the seat belt by the spindle assembly 10 stops, the load of the occupant on the seat belt causes a portion of the spindle assembly 10 to rotate in the seat belt unwinding direction D2 before stopping. The operation of the spindle assembly 10 will be described in more detail later.

[0026] In the following explanation, the rotation of the spindle assembly 10 in the winding direction D1 during the operation of the pretensioner 20 is sometimes referred to as "winding rotation," and the process by which the spindle assembly 10 performs winding rotation is sometimes referred to as the "winding process." After the operation of the pretensioner 20 has stopped, the rotation of a part of the spindle assembly 10 in the unwinding direction D2 is sometimes referred to as "unwinding rotation," and the process by which the spindle assembly 10 performs unwinding rotation is sometimes referred to as the "start of unwinding rotation" of the lock ring 80.

[0027] [Configuration of spindle assembly 10] Next, the configuration of the spindle assembly 10 will be described in detail with reference to Figures 1 to 7F.

[0028] As shown in Figures 1 and 2, the spindle assembly 10 includes a spindle 70 around which the seat belt is wound, a tread head 40, a torsion bar 50, and a sleeve 60 provided in a transmission path that transmits force from the pretensioner 20 to the spindle 70, a lock ring 80 provided between the tread head 40 and the spindle 70, and a stopper 90 that can stop the spindle 70 from unwinding.

[0029] (Spindle 70) The spindle 70 is an example of a configuration for winding a seat belt. The spindle 70 is cylindrical in shape. As shown in Figures 1 to 4, the spindle 70 has an open end 71, a closed end 72 on the opposite side of the open end 71, a mounting portion 73 provided on the outer circumferential surface 710 of the cylinder for attaching a seat belt, an internal space 74 formed inside the cylinder to accommodate a part of the torsion bar 50, a groove 75 provided on the internal space 74 side of the closed end 72 for engaging with the end of the torsion bar 50, and a second engaging receiving portion 76 provided on the inner circumferential surface of the cylinder for engaging with the sleeve 60.

[0030] The groove 75 is, for example, in the shape of a Torx screw. As shown in Figures 1 and 3, the outer circumferential Torx portion 77 is provided on the outer circumferential Torx portion 77 of the open end 71 for engaging with the inner circumferential Torx portion 93 of the stopper 90, which will be described later. As shown in Figures 1 and 3, a mounting pin 78 for engaging the lock ring 80 is provided on the end face 771 of the outer circumferential Torx portion 77.

[0031] The mounting pin 78 is an example of a first mounting portion for attaching the lock ring 80 to the spindle 70. The mounting pin 78 is inserted into the mounting hole 818 of the lock ring 80, which will be described later, and the connection with the mounting hole 818 enables the lock ring 80 to be attached to the spindle 70. The mounting pin 78 is also a thin pin and is configured to be easily sheared when relative rotation occurs between the spindle 70 and the lock ring 80. The connection between the spindle 70 and the lock ring 80 is released by shearing the mounting pin 78.

[0032] (Treadhead 40) The tread head 40 is configured to rotate in the winding direction D1 in response to the force from the pretensioner 20, that is, it is an example of a configuration provided at the upstream end of the transmission path. The tread head 40 is cylindrical. As shown in Figures 1 to 4, the tread head 40 has a closed end 41 rotatably attached to the drive cover 22 of the pretensioner 20, an open end 42 on the opposite side of the closed end 41, a pinion 43 formed on the outer circumferential surface of the cylinder, an internal space 44 formed inside the cylinder to accommodate the other part of the torsion bar 50, and a groove 45 provided on the internal space 44 side of the closed end 41 for engaging with the other end of the torsion bar 50.

[0033] The groove 45 is, for example, Torx-shaped. The open end 42 is provided with a first mounting portion 46 for engaging with one end 81 of the lock ring 80, which will be described later, as shown in Figure 2. In addition, when the operation of the pretensioner 20 is stopped by a stopping device (not shown), the tread head 40 stops rotating relative to the frame body 31.

[0034] (Torsion bar 50) The torsion bar 50 is an example of a configuration that transmits the winding rotation of the tread head 40 to the sleeve 60. As shown in Figures 1 and 2, the torsion bar 50 has a first bar 51 and a second bar 52 arranged coaxially. The first bar 51 and the second bar 52 are separate parts having different properties. The torsional rigidity of the first bar 51 is greater than that of the second bar 52. In the example shown in Figures 1 and 2, the first bar 51 is formed to be thicker than the second bar 52.

[0035] As shown in Figures 1 and 2, the first bar 51 has a first head-side end 53 fixed to the groove 45 of the tread head 40 and a first sleeve-side end 55 fixed to the inner circumferential surface of the sleeve 60. As shown in Figure 2, the first sleeve-side end 55 is provided with a groove 57. As shown in Figures 1 and 2, the second bar 52 has a second spindle-side end 54 fixed to the spindle 70 and a second sleeve-side end 56 attached to the first sleeve-side end 55.

[0036] The first head-side end 53, the first sleeve-side end 55, and the second spindle-side end 54 each have a Torx shape. The first sleeve-side end 55 is an example of a first engagement receiving portion for engaging with the first engagement portion 623 of the sleeve 60, which will be described later. The first sleeve-side end 55 is configured to slide in the direction of the rotation axis without rotating relative to the first engagement portion 623.

[0037] The second sleeve end 56 is press-fitted into the groove 57 of the first sleeve end 55 and joined to the first sleeve end 55. In other words, the first bar 51 and the second bar 52 are integrally connected without relative rotation by the connection of the second sleeve end 56 to the first sleeve end 55.

[0038] Although the torsion bar 50 has been described here as being composed of two bars, the torsion bar 50 may consist of three or more bars, or a single bar with different properties along its longitudinal direction. Furthermore, the method of connecting the first bar 51 and the second bar 52 is not limited to press-fitting, but may also be other methods such as welding.

[0039] (Sleeves 60) The sleeve 60 is an example of a configuration that can transmit the winding rotation of the first bar 51 of the torsion bar 50 to the spindle 70. The sleeve 60 is coupled to the outer circumferential surface (first sleeve side end 55) of the first bar 51 in the transmission path and is configured to be detachable from the spindle 70. Specifically, the sleeve 60 is coupled to the spindle 70 so as to rotate the spindle 70 in the winding direction D1 when the pretensioner 20 is operating, and after the pretensioner 20 stops operating, the spindle 70 is rotated in the belt unwinding direction D2 by the load of the occupant on the belt, and the sleeve 60 is configured to separate from the spindle 70 after a predetermined stroke. Here, the predetermined stroke is, for example, a predetermined angle by which the sleeve 60 rotates in the unwinding direction D2 due to the unwinding rotation of the spindle 70.

[0040] Furthermore, the sleeve 60 is cylindrical in shape. As shown in Figures 1 to 4, the sleeve 60 has a first portion 61 that includes an open end facing the tread head 40, and a second portion 62 that includes an open end that is inserted into the spindle 70. The diameter of the outer circumferential surface 611 of the first portion 61 is larger than the diameter of the outer circumferential surface 621 of the second portion 62. The sleeve 60 is also configured to engage with the spindle 70 via a second engaging portion 626 of the second portion 62, which will be described later.

[0041] As shown in Figure 3, a projection 612 is provided on the outer circumferential surface 611 of the first part 61. As shown in Figures 3 and 6, the projection 612, together with a cam 812 provided on the lock ring 80 (described later), constitutes a movable part 610. When the movable part 610 functions, it moves the sleeve 60 in a first direction (see Figure 1), separating the sleeve 60 from the spindle 70. The projection 612 is an example of the first movable part of the movable part 610, and the cam 812 is an example of the second movable part of the movable part 610. The operation when the movable part 610 functions will be described in detail in the description of the operation of the spindle assembly 10 (described later).

[0042] As shown in Figures 2 and 4, a first engaging portion 623 is provided on the inner circumferential surface 622 of the second portion 62. The first engaging portion 623 has a Torx shape corresponding to the shape of the first sleeve-side end 55 of the first bar 51. The first engaging portion 623 can be connected to the first sleeve-side end 55 of the first bar 51 so as to be slidable in the direction of the rotation axis (see Figure 1) without relative rotation.

[0043] As shown in Figures 1 and 3, the outer circumferential surface 621 of the second portion 62 is provided with a second engaging portion 626 for engaging with the second engaging receiving portion 76 of the spindle 70. The second engaging portion 626 can be connected to the second engaging receiving portion 76 of the spindle 70 so as to be slidable in the direction of the rotation axis (see Figure 1) without relative rotation. Furthermore, the second engaging portion 626 is configured to be able to engage with and disengage from the second engaging receiving portion 76 of the spindle 70.

[0044] (Lock ring 80) The lock ring 80 is an example of a configuration used to detect the number of rotations the spindle 70 is fed out. When the pretensioner 20 is activated, the lock ring 80 rotates with the spindle 70 in the winding direction D1. After the pretensioner 20 stops operating, the lock ring 80 rotates a predetermined number of times in the feeding direction D2 due to the feeding rotation of the spindle 70. After rotating a predetermined number of times in the feeding direction D2, the lock ring 80 is stopped from rotating by the pawl 32.

[0045] The lock ring 80 is ring-shaped. As shown in Figure 2, the lock ring 80 is provided between the tread head 40 and the spindle 70. As shown in Figures 1 to 4, the lock ring 80 has one end 81 facing the tread head 40, the other end 82 which is an open end facing the spindle 70, ratchet teeth 83 formed on the outer circumferential surface 810 of the ring, and female threads 84 formed on the inner circumferential surface 820 of the ring.

[0046] One end 81 has an end face plate 811, as shown in Figure 1. The end face plate 811 has a first end face 811a facing a first direction and a second end face 811b facing a second direction, as shown in Figures 1, 3, and 4. The first end face 811a is provided with a second mounting portion 86 for attaching the lock ring 80 to the outer circumference of the first mounting portion 46 of the tread head 40. The lock ring 80 is supported by the tread head 40 by the attachment of the first mounting portion 46 and the second mounting portion 86.

[0047] Furthermore, as shown in Figures 1 and 3, a mounting hole 818 is formed at one end 81, penetrating the end plate 811 in the thickness direction. The mounting hole 818 is an example of a mounting portion (second mounting portion) for attaching the lock ring 80 to the spindle 70. The mounting hole 818 is connected to a mounting pin 78 when the pretensioner 20 is operating, and is configured to shear the mounting pin 78 by the relative rotation between the lock ring 80 and the spindle 70 after the pretensioner 20 has stopped operating. In this way, the lock ring 80 is attached to the spindle 70 when the pretensioner 20 is operating, and is configured to separate from the spindle 70 after the pretensioner 20 has stopped operating.

[0048] Furthermore, as shown in Figures 1 and 3, a cam 812 corresponding to a projection 612 of the sleeve 60 is provided on the first end face 811a of one end 81. The cam 812 is an example of a second movable part corresponding to a projection 612 of the sleeve 60. The cam 812 is also an example of a cam structure. Here, the cam structure may be a cam groove or the like, rather than a configuration like the cam 812.

[0049] The female thread 84 is configured to screw into the male thread 94 of the stopper 90, which will be described later. Furthermore, as shown in Figure 4, the female thread 84 is formed from the other end 82 to the second end face 811b. This female thread 84 allows the end 911 of the stopper 90 to come into contact with the second end face 811b at a predetermined number of rotations, thereby fixing the stopper 90 so that it does not rotate relative to the lock ring 80.

[0050] The ratchet teeth 83 are an example of an engaging receiving portion that can engage with the pawl portion 324 of the pawl 32. Together with the pawl 32, the ratchet teeth 83 constitute a locking mechanism that stops the unwinding rotation of the lock ring 80. During the winding process, the ratchet teeth 83 of the lock ring 80 and the pawl portion 324 of the pawl 32 do not engage, and both allow the winding rotation of the lock ring 80. On the other hand, when the lock ring 80 is rotated in the unwinding direction D2 by the spindle 70, the ratchet teeth 83 of the lock ring 80 and the pawl portion 324 of the pawl 32 engage, fixing the lock ring 80 to the frame 30 and stopping the rotation of the lock ring 80 in the unwinding direction D2. Thus, relative rotation occurs between the lock ring 80 and the spindle 70.

[0051] Furthermore, when relative rotation occurs between the lock ring 80 and the spindle 70, the stopper 90 rotates with the spindle 70 relative to the lock ring 80. By obtaining the number of rotations the stopper 90 has made relative to the lock ring 80, it is possible to detect the number of rotations the spindle 70 has made out in the payout direction D2 after the pretensioner 20 has stopped operating.

[0052] Furthermore, when the lock ring 80 stops, the mounting pin 78 of the spindle 70 is sheared by the mounting hole 818 of the stopped lock ring 80. In this way, the lock ring 80 is released from its connection with the spindle 70.

[0053] (Stopper 90) The stopper 90 is an example of a configuration for stopping the payout rotation of the spindle 70. As shown in Figures 2 and 4, the stopper 90 is provided between the inner circumferential surface 820 of the lock ring 80 and the outer circumferential Torx portion 77 provided on the outer circumferential surface of the open end of the spindle 70. The stopper 90 is also ring-shaped. As shown in Figures 1, 2, and 4, the stopper 90 has an outer circumferential surface 910 that can rotate relative to the lock ring 80 and an inner circumferential surface 920 that engages with the outer circumferential Torx portion 77 of the spindle 70.

[0054] As shown in Figures 1 and 4, the inner circumferential surface 920 of the stopper is provided with an inner circumferential Torx portion 97 for engaging with the outer circumferential Torx portion 77 of the spindle 70. The stopper 90 is provided so as to be movable relative to the spindle 70 without rotating relative to it, due to the engagement of the inner circumferential Torx portion 97 with the outer circumferential Torx portion 77 of the spindle 70. Therefore, the stopper 90 can rotate together with the spindle 70.

[0055] As shown in Figures 1 and 4, the outer circumferential surface 910 of the stopper is provided with a male screw 94 for screwing into the female screw 84 of the lock ring 80. When the spindle 70 rotates in the unwinding direction D2 relative to the lock ring 80, the stopper 90 is screwed in along the female screw 84 of the lock ring 80 from the other end 82 to the first end 81 so as to approach the second end face 811b of the lock ring 80, and moves away from the spindle 70 along the outer circumferential Torx portion 77. Also, as shown in Figures 1 to 3, when the end face 901 of the end 911 of the stopper 90 comes into contact with the second end face 811b of the lock ring 80, the stopper 90 is fixed to the lock ring 80, and the rotation of the stopper 90 is stopped. Therefore, the unwinding rotation of the spindle 70 engaged with the stopper 90 is also stopped.

[0056] <Operation of spindle assembly 10> Next, the operation of the spindle assembly 10 during a vehicle collision will be described in detail with reference to Figures 1 to 7F.

[0057] As described above, the spindle assembly 10 is configured such that, in the event of a vehicle collision, the pretensioner 20 activates, causing the spindle assembly 10 to perform winding rotation. Subsequently, when the pretensioner 20 stops operating, the winding rotation of the spindle assembly 10 stops, a portion of the spindle assembly 10 performs unwinding rotation, and then the operation of the entire spindle assembly 10 stops. For this reason, the following will describe in detail the operation of the spindle assembly 10 during a vehicle collision, in the following order: "winding process" when the pretensioner 20 is activated, "state immediately after winding stops" after the pretensioner 20 stops operating, "unwinding process," and "operation stopped state."

[0058] [When pretensioner 20 is activated] (winding process) During a vehicle collision, the pretensioner 20 activates, causing the spindle assembly 10 to rotate in the winding direction D1 to rewind the seat belt, thus initiating the winding process. In the winding state, the force from the pretensioner 20 is output through the transmission path and transmitted to the spindle 70 in the following order: the tread head 40, the first bar 51 of the torsion bar 50, and the sleeve 60. The spindle 70 is then rotated in the winding direction D1 by this force.

[0059] In this case, the rotation of the first bar 51 in the winding direction D1 causes the second bar 52, which is connected to the first bar 51, to also rotate in the winding direction D1. The second spindle-side end 54 and the second sleeve-side end 56 of the second bar 52 are fixed to the spindle 70 and the first bar 51, respectively. The rotation of the first bar 51 and the spindle 70 in the winding direction D1 prevents the second bar 52 from twisting. In addition, the winding rotation of the spindle 70 causes the stopper 90 and the lock ring 80, which are engaged with the spindle 70, to rotate in the winding direction D1 along with the rotation of the spindle 70.

[0060] Furthermore, during the winding process, the first engaging portion 623 of the sleeve 60 and the first sleeve-side end 55 of the first bar 51 are connected. The sleeve 60 is connected to the first bar 51 by the connection between the first engaging portion 623 and the first sleeve-side end 55. The sleeve 60 is then rotated in the winding direction D1 by the first bar 51.

[0061] Furthermore, during the winding process, the second engaging portion 626 of the sleeve 60 and the second engaging receiving portion 76 of the spindle 70 are connected. The sleeve 60 is connected to the spindle 70 by the second connection between the second engaging portion 626 and the second engaging receiving portion 76. The sleeve 60 then transmits the winding rotation of the first bar 51 to the spindle 70, causing the spindle 70 to rotate in the winding direction D1.

[0062] Furthermore, during the winding process, the projection 612 of the sleeve 60 and the cam 812 of the lock ring 80 are rotated at the same speed in the winding direction D1 by the winding rotation of the sleeve 60 and the spindle 70, respectively. As a result, the projection 612 does not move along the cam 812, and the sleeve 60 does not move away from it.

[0063] Furthermore, during the winding process, the mounting pin 78 of the spindle 70 is connected to the mounting hole 818 of the lock ring 80. Since the spindle 70 and the lock ring 80 rotate in the winding direction D1 at the same speed, the mounting pin 78 is not sheared, and the lock ring 80 rotates together with the spindle 70 during the winding process.

[0064] Furthermore, during the winding process, the stopper 90 is located on the other end 82 side of the lock ring 80, as shown in Figure 7A. Since the stopper 90 and the lock ring 80 are rotated in the winding direction D1 at the same speed by the spindle 70, there is no relative rotation between the stopper 90 and the lock ring 80. Therefore, the stopper 90 does not move along the female thread 84 of the lock ring 80 toward the second end face 811b of the lock ring 80.

[0065] Furthermore, during the winding process, as shown in Figure 5B, the ratchet teeth 83 of the lock ring 80 do not engage with the claw portion 324 of the pawl 32, but instead contact the flat portion 325 of the pawl 32, which continues to rotate in the winding direction D1 while flicking the claw portion 324 of the pawl 32. In other words, the ratchet teeth 83 of the lock ring 80 and the pawl 32 allow the winding rotation of the lock ring 80.

[0066] [After the pretensioner 20 stops operating] (Condition immediately after winding stops) Subsequently, when the pretensioner 20 stops operating, the output from the pretensioner 20 to the transmission path stops. This cessation of output stops the rotation of each component of the spindle assembly 10 in the winding direction D1.

[0067] Then, when the spindle 70 begins to rotate in the extension direction D2 due to the load of the occupant suspended in the seat belt, the lock ring 80 engaged with the spindle 70 also begins to rotate in the extension direction D2. On the other hand, when the lock ring 80 rotates slightly in the extension direction D2, the ratchet teeth 83 of the lock ring 80 rotate from the flat portion 325 of the pawl 32 toward the pawl portion 324, as shown in Figure 5C, and engage with the pawl portion 324. This engagement fixes the lock ring 80 to the frame 30 and suppresses the rotation of the lock ring 80 in the extension direction D2.

[0068] Furthermore, the lock ring 80 is fixed to the frame 30 by the pawl 32, and the stopping device is activated to stop the tread head 40 so that its position relative to the frame 30 does not change. In this way, the winding rotation of the tread head 40 is stopped. When the tread head 40 stops, the first bar 51, sleeve 60, and spindle 70, which are provided in the transmission path, are also stopped in sequence.

[0069] In this case, since both the first bar 51 and the spindle 70 are stopped, the second bar 52 is not twisted. Also, since both the tread head 40 and the spindle 70 are stopped, the first bar 51 is not twisted.

[0070] (Feeding process) Subsequently, the spindle 70 continues to rotate in the extension direction D2 due to the load of the occupant suspended in the seat belt. In this case, since the lock ring 80 is fixed to the frame 30, the rotation of the spindle 70 causes the mounting pin 78 to be sheared by the wall of the mounting hole 818, releasing the connection between the spindle 70 and the lock ring 80. Once the spindle 70 is separated from the lock ring 80, relative rotation occurs between the two.

[0071] Furthermore, during the unwinding process, the sleeve 60 separates from the spindle 70 after a predetermined stroke following the start of the spindle 70's unwinding rotation. In the following description, during the unwinding process, the period from the start of the spindle 70's unwinding rotation to the separation of the sleeve 60 from the spindle 70, as shown in Figures 7A to 7D, may be referred to as the "first section," and the period from the separation of the sleeve 60 from the spindle 70 to the stop of the spindle 70's unwinding rotation, as shown in Figures 7E and 7F, may be referred to as the "second section."

[0072] (Section 1) In the first section, as the spindle 70 is extended, the projection 612 of the sleeve 60 rotates with the spindle 70 in the extension direction D2 and begins to interfere with the contact portion 813 of the cam 812 of the lock ring 80. In other words, the moving part 610 begins to function. Here, the interference between the projection 612 and the contact portion 813 of the cam 812 means that the projection 612 comes into contact with the contact portion 813 of the stationary lock ring 80 and rotates relative to the lock ring 80. Due to the interference between the projection 612 and the cam 812, the sleeve 60 is moved in a first direction away from the spindle 70 (see Figure 1).

[0073] More specifically, in the first section, the movement unit 610 functions as a result of the spindle 70's pay-out rotation, causing the second engaging portion 626 of the sleeve 60 to move in a first direction (see Figure 1) relative to the second engaging receiving portion 76 of the spindle 70 while in contact with it, thus creating a second movement state. Then, the sleeve 60 maintains its connection with the spindle 70 due to the second movement state of the second engaging portion 626 and the second engaging receiving portion 76, and is rotated in the pay-out direction D2 by the spindle 70's pay-out rotation, while being moved in the first direction (see Figure 1) along the second engaging receiving portion 76 by the operation of the movement unit 610.

[0074] Furthermore, in the first section, the movement unit 610 is activated by the payout rotation of the spindle 70, causing the first engaging portion 623 of the sleeve 60 to move in a first direction (see Figure 1) relative to the first sleeve-side end 55 of the first bar 51, thus entering a first movement state. Then, the sleeve 60 moves away from the first engaging portion 623 and the first sleeve-side end 55, transmitting the payout rotation of the spindle 70 to the first sleeve-side end 55 of the first bar 51.

[0075] In this case, the first bar 51 has its first head-side end 53 connected to the tread head 40, and its first sleeve-side end 55 is subjected to a force in the unwinding direction by the load of the occupant transmitted in the order of spindle 70 and sleeve 60. As a result, the first bar 51 is twisted from the first sleeve-side end 55, as shown by the marked line L1 of the first bar 51 in Figures 7B to 7D. On the other hand, in this case, the second sleeve-side end 56 of the second bar 52 is attached to the spindle 70 via the sleeve 60, and the second spindle-side end 54 of the second bar 52 is connected to the spindle 70. That is, both ends of the second bar 52 are fixed to the spindle 70. Therefore, the second bar 52 is not twisted by the unwinding rotation of the spindle 70, as shown by the marked line L2 of the second bar 52 in Figures 7B to 7D.

[0076] Furthermore, in the first section, as shown in Figures 7B to 7D, the stopper 90 is screwed in along the female thread 84 of the lock ring 80 from the other end 82 to the one end 81 of the lock ring 80 by the outward rotation of the spindle 70, and moves away from the spindle 70 along the outer Torx portion 77. Then the stopper 90 approaches the second end face 811b of the lock ring 80. In this way, in the first section, the load of the occupant suspended by the seat belt is transmitted in the order of spindle 70, sleeve 60, first bar 51, and tread head 40.

[0077] (Second section) When the projection 612 passes the contact portion 813 of the cam 812, the sleeve 60 separates from the spindle 70. In the second section, the sleeve 60 stops rotating in the feed direction D2 and moving in the first direction (see Figure 1) as a result of separating from the spindle 70.

[0078] More specifically, in the second section, the relative rotation between the projection 612 and the cam 812 is stopped. In this case, the second engaging portion 626 of the sleeve 60 and the second engaging receiving portion 76 of the spindle 70 do not come into contact with each other. That is, the sleeve 60 and the spindle 70 are in a disengaged state, as shown in Figures 7E and 7F.

[0079] In this disengaged state, the spindle 70 transmits the occupant's load to the second bar 52 via the connection between the groove 75 and the second spindle-side end 54 of the second bar 52, and then further transmits the occupant's load to the first bar 51 via the connection between the second sleeve-side end 56 of the second bar 52 and the first sleeve-side end 55 of the first bar 51. In this process, the second bar 52, which has low torsional rigidity, is twisted by the transmitted occupant's load, as shown in Figures 7E and 7F. On the other hand, the first bar 51 is subjected to the torsional force due to the transmitted occupant's load, but because the torsional rigidity of the first bar 51 is higher than that of the second bar 52, the marking line L1 of the first bar 51 is not twisted further than the marking line L1 of the first bar 51 shown in Figure 7D, as shown in Figures 7E and 7F. In other words, the twisting of the first bar 51 due to the occupant's load ends at the end of the first section, while in the second section, the second bar 52 twists and absorbs the occupant's load.

[0080] Furthermore, in the second section, as shown in Figure 7F, the stopper 90 is screwed into the female thread 84 of the lock ring 80 by the outward rotation of the spindle 70, from the other end 82 of the lock ring 80 to the second end face 811b of the one end 81, and continues to move away from the spindle 70 along the outer Torx portion 77.

[0081] Thus, in the second section, the load of the occupant suspended by the seat belt is transmitted in the order of spindle 70, second bar 52, first bar 51, and tread head 40. Compared to the transmission of the occupant load in the first section, the separation of the sleeve 60 and spindle 70 in the second section allows the torsional torque from the torsion bar 50 after the pretensioner 20 stops operating to be switched from the first bar 51, which has high torsional rigidity, to the second bar 52, which has low torsional rigidity. In other words, by moving the sleeve 60 in the first direction (see Figure 1) with the lock ring 80 and separating it from the spindle 70, the switching of the functioning torsion bar, i.e., the switching between the first bar 51 and the second bar 52, can be easily achieved, and the torsional torque from the torsion bar can be reduced.

[0082] (Operation stopped) Subsequently, as shown in Figure 7F, when the end face 901 of the stopper 90 comes into contact with the second end face 811b of the lock ring 80, the stopper 90 is stopped because its relative rotation with respect to the lock ring 80 is restricted by the second end face 811b of the lock ring 80. The payout rotation of the spindle 70, which is engaged with the stopper 90, is also stopped, and the operation of the spindle assembly 10 ceases.

[0083] Furthermore, when the spindle assembly 10 is in a stopped state, the load of the occupant suspended by the seat belt continues to be applied to the spindle 70. In this case, the load of the occupant suspended by the seat belt is transmitted to the frame 30 in the following order: spindle 70, male screw 94 of stopper 90, female screw 84 of lock ring 80, ratchet teeth 83 of lock ring 80, and pawl 32.

[0084] (1) The seat belt retractor 1 according to the first embodiment described above includes a spindle 70 around which the belt is wound, a pretensioner 20 that operates to transmit a force to rotate the spindle 70 in the belt winding direction to the spindle 70 via a transmission path, a tread head 40 provided in the transmission path that rotates in the winding direction D1 upon receiving force from the pretensioner 20, a torsion bar 50 provided in the transmission path with one end fixed to the tread head 40 and the other end fixed to the spindle 70, and a provision provided between the tread head 40 and the spindle 70 The lock ring 80 is provided with the pretensioner 20. When the pretensioner 20 is activated, the rotation of the tread head 40 in the winding direction D1 is transmitted to the spindle 70 via the torsion bar 50, causing the lock ring 80 to rotate in the winding direction D1 together with the spindle 70. However, after the pretensioner 20 stops operating, the lock ring 80 is prevented from rotating, and the load of the occupant on the belt allows the spindle 70 to rotate relative to the lock ring 80 in the belt payout direction D2, causing the torsion bar 50 to twist due to the relative rotation of the spindle 70. As a result, the lock ring 80, with its simple configuration, can switch the functioning torsion bar portion and easily adjust the torsional torque of the torsion bar.

[0085] (2) In addition, in the seat belt retractor 1 according to the first embodiment described above, the torsion bar 50 has a first bar 51 fixed to the tread head 40 in the transmission path and a second bar 52 having different properties from the first bar 51 and fixed to the spindle 70, and the seat belt retractor 1 further includes a sleeve 60 attached to the outer circumferential surface of the first bar 51 and provided to be detachable from the spindle 70 in the transmission path, and the sleeve 60 is coupled to the spindle 70 so as to rotate the spindle 70 in the winding direction D1 when the pretensioner 20 is in operation, and is configured to rotate with the spindle 70 in the unwinding direction D2 due to the relative rotation of the spindle 70 after the operation of the pretensioner 20 has stopped, and to separate from the spindle 70 by interference with the lock ring 80 after a predetermined stroke, and when the sleeve 60 separates from the spindle 70, the first bar 51 is twisted and the second bar 52 is twisted. As a result, the interference between the sleeve 60 and the lock ring 80 allows for the separation of the sleeve 60 and the spindle 70.

[0086] (3) Furthermore, in the seat belt retractor 1 according to the first embodiment described above, the unwinding process in which the spindle 70 performs relative rotation after the operation of the pretensioner 20 stops has a first section from the start of relative rotation until separation, and a second section from separation until relative rotation stops. When the pretensioner 20 is operating, the sleeve 60 is rotated in the winding direction D1 by the rotation of the first bar 51 in the winding direction D1. After the operation of the pretensioner 20 stops, in the first section, while rotating in the unwinding direction D2 together with the spindle 70, it moves in a first direction, which is an example of a direction away from the spindle 70 due to interference with the lock ring 80. In the second section, it stops moving away from the spindle 70 by being separated from it, and is configured to rotate in the unwinding direction due to the load of the occupant transmitted in the order of spindle 70, second bar 52 and first bar 51, and then stop rotating in the unwinding direction. As a result, the coupling between the sleeve 60 and the spindle 70 can be easily released.

[0087] (4) In addition, the seat belt retractor 1 according to the first embodiment described above further includes a moving part 610 that moves the sleeve 60 in the away direction in a first section, the moving part 610 having a projection 612 which is an example of a first moving part provided on the sleeve 60, and a cam 812 provided on the lock ring 80 which is an example of a cam configuration corresponding to the projection 612 and is an example of a second moving part, the projection 612 is configured to move in the away direction while rotating along the cam 812 by the rotation of the sleeve 60 in the payout direction D2 so as to separate the sleeve 60 from the spindle 70 in a first section. As a result, the sleeve 60 can be moved in the away direction using a simple configuration.

[0088] (5) Furthermore, in the seat belt retractor 1 according to the first embodiment described above, when the pretensioner 20 is activated, the cam 812 rotates in the winding direction D1 together with the projection 612 due to the winding rotation of the spindle 70 in the winding direction D1. After the operation of the pretensioner 20 stops, in the first section the cam 812 rotates relative to the projection 612 while in contact with it, and in the second section the relative rotation stops. As a result, the rotation and movement of the sleeve 60 can be adjusted by the relative rotation and movement of the projection 612 and the cam 812.

[0089] (6) Furthermore, in the seat belt retractor 1 according to the first embodiment described above, a first engaging portion 623 is provided on the inner circumferential surface of the sleeve 60, and a first sleeve-side end portion 55, which is an example of a first engaging receiving portion, is provided on the outer circumferential surface of one end of the first bar 51, which engages with the first engaging portion 623 without relative rotation and is movable relative to the first engaging portion 623. In the process of the sleeve 60 separating from the spindle 70 after the operation of the pretensioner 20 stops, the first engaging portion 623 of the sleeve 60 moves relative to the first sleeve-side end portion 55 of the first bar 51, and the relative rotational force of the spindle 70 is input from the first engaging portion 623 of the sleeve 60 to the first sleeve-side end portion 55 of the first bar 51, while the relative rotational force of the spindle 70 is input to the second bar 52 after the sleeve 60 separates from the spindle 70. As a result, the attachment of the sleeve 60 and the first bar 51 can be achieved using a simple configuration.

[0090] (7) Furthermore, in the seat belt retractor 1 according to the first embodiment described above, a second engagement portion 626 is provided on the outer circumferential surface of the sleeve 60, and a second engagement receiving portion 76 is provided on the inner circumferential surface of the spindle 70 that does not rotate relative to the second engagement portion 626 and engages with the second engagement portion 626 so as to be movable in a first direction. In the process of the sleeve 60 separating from the spindle 70 after the operation of the pretensioner 20 has stopped, the second engagement portion 626 of the sleeve 60 moves in a first direction relative to the second engagement receiving portion 76 of the spindle 70, and this movement releases the engagement between the second engagement portion 626 and the second engagement receiving portion 76, thereby separating the sleeve 60 from the spindle 70. As a result, the sleeve 60 can be adjusted to separate from the spindle 70.

[0091] (8) Furthermore, the seat belt retractor 1 according to the first embodiment described above is further provided with a stopper 90 for stopping the relative rotation of the spindle 70 in the payout direction D2, wherein the stopper 90 is provided so as not to rotate relative to the spindle 70 but to move in a first direction relative to the spindle 70, and after the operation of the pretensioner 20 is stopped, the stopper 90 moves in the first direction relative to the spindle 70 due to the relative rotation of the spindle 70 in the payout direction D2, and this movement is restricted by the lock ring 80, thereby stopping the relative rotation of the spindle 70 in the payout direction D2. As a result, the payout rotation of the spindle 70 can be stopped using a simple configuration.

[0092] (9) Furthermore, in the seat belt retractor 1 according to the first embodiment described above, in the first section, the first bar 51 is twisted by the load of the occupant transmitted in the order of spindle 70 and sleeve 60, and then the sleeve 60 separates from the spindle 70 and the first bar 51 is no longer twisted, while the second bar 52 is not twisted because no load is applied to it due to the engagement of the spindle 70 and sleeve 60. In the second section, the first bar 51 and the second bar 52 are connected in series, and of the first bar 51 and the second bar 52, only the second bar 52 is twisted by the load of the occupant. In this way, by switching the object that is twisted during the unwinding process from the first bar 51 to the second bar 52, the torsional torque of the torsion bar 50 can be adjusted.

[0093] (10) The first bar 51 has a first head-side end 53 fixed to the tread head 40 and a first sleeve-side end 55 engaged with the inner circumferential surface of the sleeve 60, and the second bar 52 has a second spindle-side end 54 fixed to the spindle 70 and a second sleeve-side end 56 attached to the first sleeve-side end 55 or engaged with the inner circumferential surface of the sleeve 60. As a result, the connection of the three components, the sleeve 60, the first bar 51, and the second bar 52, can be easily achieved.

[0094] (11) Furthermore, in the seat belt retractor 1 according to the first embodiment described above, the torsional rigidity of the first bar 51 is greater than that of the second bar 52. As a result, after the pretensioner 20 stops operating, the torsional torque of the torsion bar 50 in the second section can be made smaller than the torsional torque of the torsion bar 50 in the first section.

[0095] [Second Embodiment] Next, a seat belt retractor according to the second embodiment will be described with reference to Figures 8 to 10. Here, the difference between the seat belt retractor according to the second embodiment and the seat belt retractor 1 according to the first embodiment is the configuration of the spindle assembly 100 and the energy absorbing member 600 provided on the spindle assembly 100. In the following, the spindle assembly 100 and the energy absorbing member 600 according to the second embodiment will be described in detail. Note that parts identical to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0096] As shown in Figures 8 and 9, the spindle assembly 100 includes a spindle 700 around which a seat belt is wound, a tread head 40, a torsion bar 500, and an energy absorbing member 600 provided in a transmission path that transmits force from a pretensioner 20 (not shown) to the spindle 700, a lock ring 800 that can block the transmission path and stop the winding rotation of the spindle 700, and a stopper 90 that can stop the unwinding rotation of the spindle 700.

[0097] Thus, the difference between the spindle assembly 100 according to the second embodiment and the spindle assembly 10 according to the first embodiment is that the spindle assembly 100 according to the second embodiment achieves the same effect as the combination of the first bar 51 and the second bar 52 and the sleeve 60 in the unwinding process of the spindle assembly 10 according to the first embodiment by combining the torsion bar 500 and the energy absorbing member 600.

[0098] The torsion bar 500 is a single bar. As shown in Figure 9, the first end 510 of the torsion bar 500 engages with the tread head 40, and the second end 520 engages with a groove 750 located inside the spindle 700.

[0099] The lock ring 800 is ring-shaped. As shown in Figure 8, the lock ring 800 has one end 801 and the other end 802. Both the one end 801 and the other end 802 are open ends. Also, as shown in Figure 8, the lock ring 800 has a first projection 803 and a second projection 804 provided on the end face of the one end 801 of the lock ring 800 for squeezing the energy absorbing member 600. The first projection 803 and the second projection 804 are examples of interference parts that interfere with the energy absorbing member 600.

[0100] The spindle 700 is cylindrical in shape. The spindle 700 has an open end 701 and a closed end 702 on the opposite side of the open end 701. The end face of the open end 701 has a mounting projection 703 and a mounting portion 704. The mounting projection 703 is an example of a mounting portion that can contact the energy absorbing member 600 of the spindle 700. The mounting projection 703 and the mounting portion 704 of the spindle 700 are located inside the lock ring 800 so as to protrude through the opening at one end 801 of the lock ring 800.

[0101] The energy absorbing member 600 is fixed to the spindle 700 and is an example of a configuration for absorbing energy caused by the spindle 700's rotation during the feeding process. The energy absorbing member 600 is ring-shaped. As shown in Figure 8, the energy absorbing member 600 has a first mounting portion 660, a second mounting portion 680, and a contact portion 670 distributed around the circumference of the ring. The contact portion 670 has an opening 690.

[0102] Furthermore, as shown in Figure 10, the energy absorbing member 600 is provided at the open end 701 of the spindle 700 and one end 801 of the lock ring 800 such that the first mounting portion 660 is sandwiched between the mounting portion 704 and the second projection 804, the second mounting portion 680 fits onto the first projection 803, and the contact portion 670 fits onto the mounting projection 703.

[0103] In this way, during the winding process, all components of the spindle assembly 100 perform the winding rotation. In this case, the mounting projection 703 does not move relative to the contact portion 670, and no energy is absorbed by the energy absorption member 600. Also, the torsion bar 500 is not twisted.

[0104] If the driving force from the pretensioner 20 exceeds the transmission capacity of the torsion bar 500 and the energy absorption member 600, pre-torsion occurs due to the pretensioner 20. However, even if the torsion bar 500 and the energy absorption member 600 are twisted, the lock ring 800 and the spindle 700 do not undergo relative displacement when rotating in the winding direction D1, so the set stroke does not change.

[0105] On the other hand, when the unwinding process begins, the lock ring 800 is fixed to the frame 30 and the spindle 700 rotates in the unwinding direction D2. The unwinding rotation of the spindle 700 twists the torsion bar 500 from the second end 520, and the mounting projection 703 of the spindle 700 rotates in the unwinding direction D2.

[0106] Furthermore, during the unwinding process, the first projection 803 of the lock ring 800 is configured such that, in the relative rotation of the spindle 70, interference with the energy absorbing member 600 occurs in accordance with the change in the rotation angle of the spindle 70, and then this interference is released. Specifically, during the unwinding process, the first projection 803 moves toward the opening 690 of the contact portion 670 while in contact with the contact portion 670 of the energy absorbing member 600, and then exits the contact portion 670 through the opening 690. As a result, the first projection 803 no longer comes into contact with the energy absorbing member 600.

[0107] Furthermore, during the contact process in which the first projection 803 moves while in contact with the second mounting portion 680, the energy of the spindle 700's rotational feed is absorbed by the energy absorption member 600, increasing the load required to twist the torsion bar 500. On the other hand, when the first projection 803 moves out of the opening 690 and out of the second mounting portion 680, entering the non-contact process, the first projection 803 no longer comes into contact with the energy absorption member 600, and the energy of the spindle 700's rotational feed is no longer absorbed by the energy absorption member 600. As a result, the load required to twist the torsion bar 500 becomes smaller compared to the load required to twist the torsion bar 500 during the contact process.

[0108] According to this second embodiment, the spindle assembly 100 according to the second embodiment, like the spindle assembly 10 according to the first embodiment, can use a simple configuration to switch the torsional torque by the torsion bar after the pretensioner stops operating, and the combination of the torsion bar 500 and the energy absorbing member 600 can achieve the same torsional torque adjustment effect as the combination of the first bar 51 and the second bar 52 and the sleeve 60 during the unwinding process of the spindle assembly 10 according to the first embodiment.

[0109] [Third Embodiment] Next, the seat belt retractor according to the third embodiment will be described with reference to Figures 11A to 11C. Here, the difference between the seat belt retractor according to the third embodiment and the seat belt retractor 1 according to the first embodiment is the configuration relating to the engagement between the lock ring 80 and the frame 30. In the following, the configuration relating to the engagement between the lock ring 80 and the frame 30 according to the third embodiment will be described in detail. Note that parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted or simplified.

[0110] As shown in Figure 11A, the frame 30 comprises a frame body 31 and a latch ring 32R provided on the frame body 31. The latch ring 32R is configured to restrict the rotational direction of the lock ring 80. The latch ring 32R has ratchet teeth 321H on its inner circumferential surface. The ratchet teeth 321H are configured to engage with the teeth 831 of the ring pawl 83H of the lock ring 80, which will be described later. In the third embodiment, the latch ring 32R was described as part of the frame 30, but it is not limited to this. The latch ring 32R may be a separate component from the frame 30.

[0111] As shown in Figure 11A, the lock ring 80 has a ring pawl 83H provided on the outer circumferential surface 810 of the ring. The ring pawl 83H is an example of an engagement receiving portion that can engage with the ratchet teeth 321H of the latch ring 32R of the frame body 31. As shown in Figure 11A, the ring pawl 83H has a pawl body 830, a rotating shaft 832 for attaching the pawl body 830 to the outer circumferential surface 810 of the lock ring 80, and a biasing mechanism (not shown). The pawl body 830 also has teeth 831 provided on one side of the rotating shaft 832, an end portion 833 provided on the other side of the rotating shaft 832, and an inner side surface 834. The pawl body 830 is configured to rotate around the rotating shaft 832 as its central axis. The rotating shaft 832 biasing mechanism is configured to bias the end portion 833 with a force that rotates the teeth 831 of the ring paw toward the latch ring.

[0112] The end portion 833 is configured to be biased against the ratchet teeth 321H of the latch ring 32R by a biasing mechanism (not shown). In the normal state, the end portion 833 is in a first position in contact with the projection 433 of the tread head 40, as shown in Figure 11A. In this case, the biasing mechanism presses the end portion 833 against the projection 433. This contact between the end portion 833 and the projection 433 keeps the teeth 831 of the pawl body 830 in a position where they do not engage with the ratchet teeth 321H of the latch ring 32R.

[0113] On the other hand, as shown in Figure 11B, when the end portion 833 moves to a second position where it does not contact the projection 433 of the tread head 40, the biasing mechanism causes the end portion 833 to rotate in a direction that presses it against the outer circumferential surface 810 of the lock ring 80.

[0114] Here, we will explain the movement of the end portion 833 from the first position shown in Figure 11A to the second position shown in Figure 11B. When the end portion 833 rotates with the spindle 70 while in contact with the projection 433 of the tread head 40, there is no relative rotation (phase difference) between the tread head 40 and the spindle 70, so the end portion 833 and the projection 433 are in the first position where they are in contact with each other, as shown in Figure 11A. On the other hand, when the pretensioner 20 is activated, the spindle 70 begins to rotate with a delay in the transmission of force from the pretensioner 20, causing relative rotation between the tread head 40 and the spindle 70. This relative rotation causes the first bar 51, which is fixed to a sleeve 60 with one end fixed to the tread head 40 and the other end connected to the spindle 70, to be pre-twisted. As a result, the end portion 833 moves from the first position shown in Figure 11A to the second position shown in Figure 11B, so as to be out of position with respect to the projection 433. Furthermore, in this case, since the lock ring 80 and spindle 70 are rotating in the winding direction D1, the pawl body 830 is biased by the biasing mechanism to a position where it can engage with the ratchet teeth 321H, as shown in Figure 11B, but it does not engage with the ratchet teeth 321H.

[0115] Then, after the pretensioner 20 stops operating, the spindle 70 rotates in the payout direction D2, so the pawl body 830 is pushed toward the ratchet teeth 321H by the biasing mechanism and engages with the ratchet teeth 321H. In this way, as shown in Figure 11C, the lock ring 80 is restrained to the frame 30.

[0116] Furthermore, if no relative rotation occurs between the tread head 40 and the lock ring 80 when the pretensioner 20 is activated, the projection 433 will remain in contact with the end 833 without moving. In this case, the torsion bar 50 is configured such that the first bar 51 engages with the tread head 40, whose position does not change relative to the frame 30, and the second bar 52 engages with a groove 75 inside the spindle 70. Therefore, when the spindle 70 subsequently rotates outwards, the torsion bar 50 begins to twist. As a result, the end 833 moves away from the projection 433.

[0117] According to this third embodiment, the spindle assembly 10 according to the third embodiment, like the spindle assembly 10 according to the first embodiment, can use a simple configuration to switch the torsional torque by the torsion bar after the pretensioner has stopped operating, and can also activate the ring pawl 83H of the lock ring 80 depending on whether or not there is relative rotation between the tread head 40 and the lock ring 80. [Explanation of Symbols]

[0118] 1... Retractor for seat belt, 10, 100... Spindle assembly, 20... Pretensioner, 21... Drive unit, 22... Drive cover, 23... Distance plate, 24... Tube housing, 25... Gas generator, 26... Spring, 27... Piston, 28... Ball, 29... Cap, 30... Frame, 31... Frame body, 32... Pawl, 32R... Latch ring, 324... Claw section, 40... Tread head, 43... Pinion, 50, 500... Torsion bar, 51... First bar, 5 2...Second bar, 53...First head side end, 54...Second spindle side end, 55...First sleeve side end, 56...Second sleeve side end, 60...Sleeve, 70, 700...Spindle, 80, 800...Lock ring, 83...Ratchet teeth, 90...Stopper, 321, 830...Pawl body, 321H...Ratchet teeth, 410...Pinion, 500...Torsion bar, 600...Energy absorbing member, 610...Moving part, 612...Projection, 812...Cam, D1...Winding direction, D2...Payout direction

Claims

1. The spindle around which the belt is wrapped, A pretensioner that operates to transmit a force to rotate the spindle in the winding direction of the belt to the spindle via a transmission path, A tread head is provided in the transmission path and rotates in the winding direction upon receiving the force from the pretensioner, A torsion bar is provided in the transmission path, with one end fixed to the tread head and the other end fixed to the spindle, A locking ring provided between the tread head and the spindle is provided, The aforementioned lock ring is When the pretensioner is activated, the rotation of the tread head in the winding direction is transmitted to the spindle via the torsion bar, causing it to rotate together with the spindle in the winding direction, After the pretensioner stops operating, rotation is prevented, and the spindle is allowed to rotate relative to the lock ring in the direction of belt payout due to the load of the occupant placed on the belt. The torsion bar is twisted by the relative rotation of the spindle, The torsion bar comprises a first bar fixed to the tread head in the transmission path, and a second bar having different properties from the first bar and fixed to the spindle. The transmission path further includes a sleeve attached to the outer circumferential surface of the first bar and provided to be detachable from the spindle, The aforementioned sleeve is When the pretensioner is activated, it is coupled to the spindle so as to rotate the spindle in the winding direction. The pretensioner is configured to rotate with the spindle in the feed direction due to the relative rotation of the spindle after the pretensioner has stopped operating, and to separate from the spindle after a predetermined stroke by interference with the lock ring. The sleeve is separated from the spindle, thereby switching from twisting the first bar to twisting the second bar. Retractable seat belt.

2. The unwinding process in which the spindle performs the relative rotation after the operation of the pretensioner has stopped has a first section in which the spindle passes from the start of the relative rotation until the separation, and a second section in which the spindle passes from the separation until the stop of the relative rotation. The aforementioned sleeve is In the first section, while rotating together with the spindle in the feeding direction, it moves away from the spindle due to interference with the lock ring, In the second section, the movement is stopped by separating from the spindle, and the load of the occupant transmitted in the order of the spindle, the second bar, and the first bar rotates in the extension direction, and then the rotation in the extension direction stops. A seat belt retractor according to claim 1.

3. The first section further includes a moving part that moves the sleeve in the direction of separation, The movable part comprises a first movable part including a projection or cam configuration provided on the sleeve, and a second movable part provided on the lock ring and including a cam configuration or projection corresponding to the projection or cam configuration. The first moving part is configured to move in the away direction while rotating and interfering with the second moving part as the sleeve rotates in the unwinding direction, so as to separate the sleeve from the spindle in the first section. A seat belt retractor according to claim 2.

4. The second moving part is, When the pretensioner is activated, the winding rotation of the spindle in the winding direction causes the first moving part to rotate in the winding direction together with the winding direction. After the pretensioner stops operating, it is configured to rotate relative to the first moving part while in contact with the first moving part in the first section, and to stop the relative rotation in the second section. A seat belt retractor according to claim 3.

5. A first engagement portion is provided on the inner circumferential surface of the sleeve. A first engagement receiving portion is provided on the outer circumferential surface of one end of the first bar, which engages with the first engagement portion in a manner that does not rotate relative to the first engagement portion but is movable relative to the first engagement portion. During the process in which the sleeve separates from the spindle after the pretensioner has stopped operating, the first engaging portion of the sleeve moves relative to the first engaging receiving portion of the first bar, while the relative rotational force of the spindle is input from the first engaging portion of the sleeve to the first engaging receiving portion of the first bar. A seat belt retractor according to any one of claims 1 to 4, wherein after the sleeve is separated from the spindle, the relative rotational force of the spindle is input to the second bar.

6. A second engagement portion is provided on the outer circumferential surface of the sleeve. The inner circumferential surface of the spindle is provided with a second engagement receiving portion that does not rotate relative to the second engagement portion and engages with the second engagement portion so as to be movable in the direction away from the second engagement portion. In the process of the sleeve separating from the spindle after the pretensioner has stopped operating, the second engaging portion of the sleeve moves in the direction away from the second engaging receiving portion of the spindle. This movement releases the engagement between the second engaging portion and the second engaging receiving portion, and the sleeve separates from the spindle. A seat belt retractor according to any one of claims 2 to 4.

7. The spindle further comprises a stopper for stopping the relative rotation in the feeding direction, The stopper is provided so as not to rotate relative to the spindle and to move away from the spindle, and after the pretensioner stops operating, it moves away from the spindle due to the relative rotation of the spindle in the feed direction, and this movement is restricted by the lock ring, thereby stopping the relative rotation of the spindle in the feed direction. A seat belt retractor according to claim 1.

8. In the first section, the first bar is twisted by the load of the occupant transmitted in the order of the spindle and the sleeve, and then the sleeve separates from the spindle and the first bar stops twisting, while the second bar does not twist because no load is applied to it due to the engagement between the spindle and the sleeve. In the second section, the first bar and the second bar are connected in series, and of the first bar and the second bar, only the second bar is twisted by the load of the occupant. A seat belt retractor according to any one of claims 2 to 4.

9. The first bar has a first head-side end fixed to the tread head and a first sleeve-side end engaged with the inner circumferential surface of the sleeve. The second bar has a second spindle-side end fixed to the spindle and a second sleeve-side end attached to the first sleeve-side end or engaged with the inner circumferential surface of the sleeve. A seat belt retractor according to any one of claims 1 to 4.

10. The torsional rigidity of the first bar is greater than that of the second bar. A seat belt retractor according to any one of claims 1 to 4.

11. The system further comprises an energy absorbing member fixed to the spindle, which absorbs energy due to the relative rotation of the spindle after the pretensioner has stopped operating, The lock ring has an interference portion that interferes with the energy absorbing member. A seat belt retractor according to claim 1.

12. The interfering portion of the lock ring is configured such that, in the relative rotation of the spindle after the pretensioner has stopped operating, an interference state with the energy absorbing member occurs in accordance with the change in the rotation angle of the spindle, and then this interference state is released. A seat belt retractor according to claim 11.

13. Frame and, The locking mechanism includes a mechanism that stops the rotation of the locking ring after the operation of the pretensioner has stopped. The locking mechanism is The frame and the lock ring have a pawl provided on one of them, which is configured to be movable between an engaged position in which it engages with the other of the frame and the lock ring and an unengaged position in which it does not engage. The seat belt retractor according to any one of claims 1 to 4, 11 or 12, wherein the pole is in the disengaged position when the pretensioner is activated, allowing the lock ring to rotate, and moves to the engaged position after the pretensioner is deactivated to stop the lock ring from rotating.

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