Seatbelt retractor

Abstract

A seatbelt retractor comprises a housing having a pair of side walls facing each other, a winding drum configured to wind up a webbing, a locking base which, in a vehicle emergency, is prevented from rotating in the extension direction, an impact energy absorption element which connects the winding drum and the locking base in such a way that they are integrally rotatable in a normal state, an impact energy absorption wire which is received in a slot which is provided in the winding drum to form an opening in the first end face of the winding drum, a ring which is integral with or separate from the locking base, and a stop element which is configured in such a way as to define a permissible degree of relative rotation between the winding drum and the locking base in a case in which the impact energy absorption element absorbs the impact energy.

Description

TECHNICAL AREA

[0001] The present disclosure relates to a seatbelt retractor that is capable of absorbing the impact energy of a passenger while a belt is being pulled out and that is capable of limiting the extension extent of the belt in an emergency such as a vehicle collision. TECHNICAL BACKGROUND

[0002] A seatbelt retractor is known from the prior art, configured to prevent a seatbelt from being pulled out of a vehicle in an emergency. In this seatbelt retractor, a winding drum, configured to wind the seatbelt, is rotatably mounted between a pair of side walls of a housing.

[0003] JP2020-104777A, for example, reveals a seatbelt retractor 100, which is in Fig. Figure 22 is shown. The seat belt retractor 100 uses a torsion bar 130, which is an impact energy absorption element, and an impact energy absorption wire (referred to as the “energy absorption pin” in JP2020-104777A) 140.

[0004] In particular, a winding drum (referred to as a "coil" in JP2020-104777A) 110 of the seat belt retractor 100 has a central opening 112 that opens towards an end face 111, and a locking base 120 is arranged such that it faces the end face 111. The torsion bar 130 is inserted into the central opening 112 of the winding drum 110 and comprises one end face that is opposite the locking base 120 and coupled to the winding drum 110 without being rotatable relative to the winding drum 110, and the other end face that is coupled to the locking base 120 without being rotatable relative to the locking base 120.

[0005] In a vehicle emergency, the locking base 120 is prevented from rotating in an extension direction. As a result, the winding drum 110 rotates relative to the locking base 120 while a webbing 200 is pulled out. The torsion bar 130 is configured to absorb impact energy through plastic deformation caused by twisting at that time.

[0006] Furthermore, the winding drum 110 has a slot (referred to in JP2020-104777A as the "axial directional opening") 113 to form an opening in the end face 111 facing the locking base 120, and the impact energy absorption wire 140 is received in the slot 113 in a state in which a head section protrudes. The head section of the impact energy absorption wire 140 is attached to the locking base 120, and the impact energy absorption wire 140 is configured such that it is pulled out of the opening of the slot 113 while plastically deforming in the event of a vehicle emergency to absorb impact energy.

[0007] On one surface of the locking base 120 facing the winding drum 110, an arc-shaped guide groove 121 is provided, which is concentric to the locking base 120. The impact energy absorption wire 140 is drawn out of the opening of the slot 113 while being plastically deformed and then wound around a radially inner side wall surface of the guide groove 121.

[0008] The seat belt retractor 100 has a stop element 150 which defines a permissible degree of relative rotation between the winding drum 110 and the locking base 120 when the torsion bar 130 absorbs the impact energy.

[0009] The stop element 150 is held in the central opening 112 of the winding drum 110, without being rotatable relative to the winding drum 110, but movable in an axial direction of the winding drum 110. The locking base 120 comprises a shaft section 122 coaxial with the winding drum 110. An external thread is formed on an outer circumferential surface of the shaft section 122, and the stop element 150 is screwed onto the external thread. In a vehicle emergency, the relative rotation between the winding drum 110 and the locking base 120 is limited to a predetermined extent by the stop element 150. Accordingly, the extension of the webbing 200 is restricted, and a passenger is prevented from moving beyond a predetermined distance in a forward direction.

[0010] In a case where the impact energy absorption wire 140, which is pulled out of the opening of the slot 113 of the winding drum 110, is wound around a portion of the locking base 120, as in the seatbelt retractor 100 of JP2020-104777A, the impact energy absorption wire 140 can stably absorb the impact energy. Instead of the guide groove 121 of the locking base 120, for example, in a case where the winding drum 110 has a winding section around which the impact energy absorption wire 140, pulled out of the opening of the slot 113, is wound, the impact energy absorption wire 140 slides on the winding section after plastic deformation, and thus a webbing pull-out load becomes unstable at the time of impact energy absorption due to the influence of friction caused by the sliding.

[0011] However, in the case of the seat belt retractor 100 of the JP2020-104777A, the guide groove 121 of the locking base 120 is located in a position that is separated from the stop element 150 in the axial direction of the winding drum 110, and therefore one dimension of the seat belt retractor 100 increases in the axial direction of the winding drum 110. PRESENTATION OF THE INVENTION

[0012] One aspect of non-restrictive embodiments of the present disclosure relates to the provision of a seatbelt retractor which has a stop element, can stably absorb impact energy by means of an impact energy absorption wire and can be reduced in size in an axial direction of a winding drum.

[0013] Aspects of certain non-restrictive embodiments of the present disclosure address the features described above and / or other features not described above. However, aspects of the non-restrictive embodiments are not required to address the features mentioned above, and aspects of the non-restrictive embodiments of the present disclosure need not address the features described above.

[0014] According to one aspect of the present disclosure, a seatbelt retractor is provided which has: a case with a pair of side walls facing each other; a winding drum configured to wind up a webbing, wherein the winding drum is received between the pair of side walls in such a way that it is rotatable in a winding direction and an extension direction of the webbing, wherein the winding drum has a central opening which opens into at least a first end face; a locking base arranged such that it faces the first end face of the winding drum, the locking base being prevented from being rotated in the extension direction in an emergency of the vehicle, wherein an external thread is formed coaxially with the winding drum on an outer circumferential surface of a shaft section of the locking base; an impact energy absorption element having one end coupled to the winding drum and the other end coupled to the locking base, wherein the impact energy absorption element connects the winding drum and the locking base such that they are integrally rotatable in a normal state, and the impact energy absorption element is configured to be plastically deformed in a case where a pull-out force of the webbing exceeds a predetermined value in a state where the locking base is prevented from rotating in the pull-out direction to absorb impact energy, while allowing relative rotation between the winding drum and the locking base; an impact energy absorption wire received in a slot provided in the winding drum to form an opening in the first end face of the winding drum, wherein a head section of the impact energy absorption wire projecting from the opening of the slot is attached to the locking base, wherein the impact energy absorption wire is configured to be pulled out of the opening while being plastically deformed, in a case where the winding drum and the locking base are rotated relative to absorb the impact energy; a ring that is integral or separate from the locking base, wherein the ring is configured to be coaxially rotatable relative to the winding drum, wherein the impact energy absorption wire that is pulled out of the opening is wound around an outer circumference of the ring; and a stop element which is held in the central opening without being rotatable relative to the winding drum and being movable in an axial direction of the winding drum, wherein the stop element is screwed onto the external thread of the locking base, and wherein the stop element is configured such that it defines a permissible degree of relative rotation between the winding drum and the locking base in a case where the impact energy absorption element absorbs the impact energy, wherein the stop element is configured such that it is movable while located radially inside the ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Exemplary embodiments of the present invention are described in detail with reference to the following figures: Fig. Figure 1 is a perspective view of a seatbelt retractor according to an embodiment of the present disclosure; Fig. 2 is a perspective exploded view of the in Fig. 1 shown seatbelt retractor; Fig. 3 is a cross-sectional view of the in Fig. 1 shown seatbelt retractor; Fig. Figure 4 is a cross-sectional view along line IV-IV in Fig. 3; Fig. 5 is a cross-section along line VV in Fig. 3; Fig. Figure 6 is a perspective exploded view of part of a winding drum unit; Fig. Figure 7 is a perspective exploded view of the rest of the winding drum unit and a synchronized gear; Fig. Figure 8 is a perspective view of a winding drum; Fig. 9 is a cross-sectional view of a lock base; Fig. Figure 10 is a perspective view of a drive wheel; Fig. Figure 11 is a perspective exploded view of a locking base main body and a locking element; Fig. Figure 12 is a perspective exploded view of the locking base main body and the locking element as seen from an opposite side; Fig. Figure 13A illustrates a state of a return spring when the locking element is in a non-engaged position; Fig. Figure 13B shows the state of the return spring when the locking element is in an engaged position. Fig. Figure 14 is a cross-sectional view of part of the winding drum unit; Fig. 15A is a cross-sectional view along line XV-XV in Fig. 14, which shows a state before the winding drum and the locking base are rotated relative to each other; Fig. 15B is a cross-sectional view along line XV-XV in Fig. 14, showing a state after the winding drum and the locking base have been rotated relative to each other; Fig. Figure 16 is a cross-sectional view of part of a winding drum unit according to a first modification; Fig. Figure 17 is a perspective exploded view of a ring and a drive wheel in the winding drum unit according to the first modification; Fig. Figure 18 is a cross-sectional view of part of a winding drum unit according to a second modification; Fig. Figure 19 is a cross-sectional view of part of a winding drum unit according to a third modification; Fig. Figure 20 is a cross-sectional view of part of a winding drum unit according to a fourth modification; Fig. Figure 21 is a cross-sectional view of part of a winding drum unit according to a fifth modification; and Fig. Figure 22 is a cross-sectional view of a seatbelt retractor from the state of the art. DESCRIPTION OF THE EXECUTION FORMS

[0016] Fig. 1 and Fig. Figure 2 illustrates a seat belt retractor 1 according to an embodiment of the present disclosure. The seat belt retractor 1 is configured to prevent a webbing 10, which is a seat belt, from being pulled out in an emergency such as a vehicle collision.

[0017] In particular, the seat belt retractor 1 comprises a housing 2, a winding spring unit 1A, a winding drum unit 1B, a belt tensioner 1C, and a locking unit 1D. The winding drum unit 1B has a winding drum 3 configured to wind the webbing 10, and the housing 2 has a first side wall 21 and a second side wall 22 facing each other in an axial direction of the winding drum 3.

[0018] The winding drum 3 is arranged between the first side wall 21 and the second side wall 22 such that it is rotatable in both a winding and an unwinding direction of the webbing 10. The housing 2 has a back plate 23, which is formed by sheet metal fabrication together with the first side wall 21 and the second side wall 22 and which is perpendicular to the first side wall 21 and the second side wall 22. For the sake of simplicity, the axial direction of the winding drum 3 is referred to as the left-right direction (one side of the first side wall 21 is referred to as the left direction and one side of the second side wall 22 as the right direction), and a thickness direction of the back plate 23 is referred to as the forward-backward direction (one side of the side walls 21 and 22 is referred to as the forward direction and an opposite side as the backward direction). As in the Fig. 1 and Fig. As shown in Figure 2, one side of a direction that is orthogonal to the left-right direction and to the front-backward direction is called an upward direction, and the other side of the direction that is orthogonal to the left-right direction and to the front-backward direction is called a downward direction.

[0019] The lower and upper sections of the front faces of the first side wall 21 and the second side wall 22 of the housing 2 are connected by connecting rods 24 and 25. The first side wall 21 and the second side wall 22 are each provided with insertion openings 21a and 22a through which the winding drum 3 is inserted. The rear wall 23 is also provided with an opening 23a through which the winding drum 3 is exposed.

[0020] The coil spring unit 1A is attached to the second side wall 22. The belt tensioner 1C is attached to the first side wall 21 of the housing 2. The locking unit 1D is attached to the belt tensioner 1C.

[0021] As in Fig. As shown in Figure 3, the winding drum 3 has a first end face 31 on one side of the first side wall 21 of the housing 2 and a second end face 32 on one side of the second side wall 22 of the housing 2. In the present embodiment, the winding drum 3 includes a shaft section 33 that projects to the right from the second end face 32, and the shaft section 33 is rotatably supported by the winding spring assembly 1A. However, a torsion bar, which is an impact energy absorption element 4A described later, can penetrate the winding drum 3, and a right end section of the torsion bar can be rotatably supported by the winding spring assembly 1A. Since a configuration of the winding spring assembly 1A is known, a detailed description is omitted.

[0022] As in the Fig. 6 and Fig. As shown in Figure 7, the winding drum unit 1B comprises, in addition to the winding drum 3, a bushing 3A, a bearing 3B, the impact energy absorption element 4A, an impact energy absorption wire 4B, a stop element 4C, a locking base 4D, a return spring 9A and a rotating shaft 9B.

[0023] The locking base 4D is arranged such that it faces the first end face 31 of the winding drum 3 and is prevented from being rotated in the extension direction in an emergency involving the vehicle. The locking base 4D has a locking base main body 6 and a drive wheel 5 attached to the locking base main body 6, which faces the first end face 31 of the winding drum 3.

[0024] The bushing 3A and the bearing 3B are emergency devices for the smooth rotation of the winding drum 3, even if the relative position of the winding drum 3 with respect to the housing 2 is displaced in a vehicle emergency. As shown in Fig. As shown in Figure 3, the bushing 3A is attached to a right end section of the winding drum 3, which is arranged in the insertion opening 22a of the second side wall 22, and the bearing 3B is attached to a left end section of the winding drum 3, which is arranged in the insertion opening 21a of the first side wall 21. Furthermore, the bearing 3B comprises a folded section 3Ba (see Figure 3). Fig. 6), which is folded back to an inside of the left end section of the winding drum 3 and is configured to slide with the drive wheel 5 in a case in which the winding drum 3 and the locking base 4D are rotated relative to each other.

[0025] The winding drum 3 has a central opening 30 that extends along a central axis of the winding drum 3. In the present embodiment, the central opening 30 is provided with a bottom and opens only at the first end face 31. However, in a case where the torsion bar, which is the impact energy absorption element 4A, penetrates the winding drum 3 as described above, the central opening 30 can open not only at the first end face 31, but also at the second end face 32.

[0026] In the present embodiment, the impact energy absorption element 4A is the torsion bar, which is inserted into the central opening 30 of the winding drum 3. The impact energy absorption element 4A has one end face that is opposite the locking base 4D and coupled to the winding drum 3 without being rotatable relative to the winding drum, and the other end face that is coupled to the locking base 4D without being rotatable relative to the locking base 4D.

[0027] In particular, the impact energy absorption element 4A, which is the torsion bar, has wedge-shaped coupling sections 41 and 42 at one and the other end, respectively. The bottom of the central opening 30 of the winding drum 3 has a wedge-shaped recess for coupling with the coupling section 41, and the coupling section 41 is fitted into the recess.

[0028] The impact energy absorption element 4A connects the winding drum 3 and the locking base 4D such that it is integrally rotatable in a normal state. Furthermore, the impact energy absorption element 4A is configured, in the event that the pull-out force of the webbing 10 exceeds a predetermined value, to plastically deform the locking base 4D in a state where it is prevented from rotating in the pull-out direction, thus absorbing impact energy while allowing relative rotation between the winding drum 3 and the locking base 4D.

[0029] The impact energy absorption wire 4B is configured such that it absorbs impact energy in an initial phase when the winding drum 3 and the locking base 4D rotate relative to each other. In the present embodiment, as shown in Fig. As shown in Figure 8, the winding drum 3 has two slots 35 for receiving the impact energy absorption wire 4B. However, the number of slots 35 can be one.

[0030] In the present embodiment, each slot 35 is formed along the axial direction of the winding drum 3 and extends over the first end face 31 and the second end face 32 of the winding drum 3. In other words, each slot 35 forms a first opening 36 in the first end face 31 and forms a second opening 37 in the second end face 32 of the winding drum 3. The bearing 3A is attached to the right end section of the winding drum 3 using the second opening 37. Furthermore, in the present embodiment, each slot 35 has the form of a groove that is cut obliquely from an outer circumferential surface of the winding drum 3. However, the slot 35 can also be an opening that extends in the axial direction of the winding drum 3.

[0031] The impact energy absorption wire 4B is received in one of the slots 35 in a state in which a head section 43 (see Fig. 6) protrudes from the first opening 36 of the slot 35. The head section 43 of the impact energy absorption wire 4B is attached to the locking base 4D. The impact energy absorption wire 4B is configured to be pulled out of the first opening 36 while plastically deformed in a case where the winding drum 3 and the locking base 4D are rotated relative to each other, in order to absorb the impact energy.

[0032] The stop element 4C defines a permissible degree of relative rotation between the winding drum 3 and the locking base 4D in a case where the impact energy absorption element 4A absorbs the impact energy. The stop element 4C is held in the central opening 30 of the winding drum 3 without being rotatable relative to the winding drum 3 and without being movable in the left-right direction.

[0033] As in Fig. As shown in Figure 6, the stop element 4C has a tubular shape through which the impact energy absorption element 4A, which is the torsion bar, is inserted. The stop element 4C is provided with an internal thread 47 on an inner circumferential surface of the stop element 4C.

[0034] In the present embodiment, the stop element 4C comprises an annular section 45 and three claw sections 46 projecting to the right from the annular section 45. The central opening 30 of the winding drum 3 has three guide grooves 34. Since the three claw sections 46 are fitted into the three guide grooves 34, the stop element 4C is held by the winding drum 3 without being rotatable relative to the winding drum 3 and without being movable in the left-right direction. Furthermore, the three claw sections 46 and the three guide grooves 34 are arranged at equal angular intervals, so that the stop element 4C is configured to be inserted into the central opening 30 of the winding drum 3 at any angular position, provided that the positions of the claw sections 46 and the guide grooves 34 coincide.In other words, the above predetermined angular interval α is equal to 120 degrees and the number of mounting positions of the stop element 4C is three.

[0035] Instead of the stop element 4C with the claw sections 46, a cross-sectional shape of an outer shape of the stop element 4C and a cross-sectional shape of a left end section of the central opening 30 of the winding drum 3 can be polygonal.

[0036] As in the Fig. 3 and Fig. As shown in Figure 9, the locking base 4D comprises a shaft section 72a, which projects to the right from the drive wheels 5 and is coaxial with the winding drum 3, and an external thread 73, onto which the internal thread 47 of the stop element 4C is screwed, is formed on an outer circumferential surface of the shaft section 72a. In the present embodiment, as shown in Fig. As shown in Figure 3, during the relative rotation between the winding drum 3 and the locking base 4D, the stop element 4C moves from a position where it is separated from the drive wheel 5 to a position where it comes into contact with the drive wheel 5, thereby limiting the relative rotation between the winding drum 3 and the locking base 4D to a predetermined extent. In other words, the stop element 4C is prevented from moving in the axial direction of the winding drum 3 by coming into contact with the drive wheel 5.

[0037] As in the Fig. 7 and Fig. As shown in Figure 10, the drive wheel 5 comprises a main body section 51 with a fitting opening having a hexagonal cross-sectional shape, a plurality of teeth 52 formed on an outer circumferential surface of the main body section 51, and an annular flange 53 projecting outwards in a radial direction from the main body section 51 on a right side of the teeth 52.

[0038] As in Fig. Figure 3 shows the flange 53 of the drive wheel 5 facing the first end face 31 of the winding drum 3. The flange 53 has a plurality (six in the illustrated example) of retaining sections 54, which are separated from each other circumferentially around a center of rotation of the winding drum 3. The head section 43 of the impact energy absorption wire 4B is attached to one of the retaining sections 54.

[0039] In the present embodiment, the retaining sections 54 are grooves that open radially outwards. The head section 43 of the impact energy absorption wire 4B comprises a detachment prevention section 44 (see Fig. 6), which is located on one side of the flange 53 opposite the winding drum 3 and which has a greater width than the groove, which is the retaining section 54. However, the retaining sections 54 can be openings that penetrate the flange 53.

[0040] The drive wheel 5 has an annular projection that extends from the flange 53 towards the first end face 31 of the winding drum 3 and is coaxial with the winding drum 3. In other words, the annular projection forms a ring 55 that is integrally provided with the drive wheel 5 between the first end face 31 of the winding drum 3 and the drive wheel 5, and which is configured to be rotatable coaxially relative to the winding drum 3. As shown in the Fig. 14, Fig. 15A and Fig. As shown in Figure 15B, the winding drum is rotated relative to the locking base 4D, whereby the impact energy absorption wire 4B, which is pulled out of the first opening 36 of the slot 35, is wound around an outer circumference of the ring 55.

[0041] An inner diameter of the ring 55 is larger than an outer diameter of the stop element 4C, and the stop element 4C is configured such that it is movable while located radially inside the ring 55. Furthermore, at least a portion of the external thread 73 formed on the shaft section 72a of the locking base 4D is located radially inside the ring 55. In the present embodiment, substantially the center of the external thread 73 is located radially inside the ring 55 in the axial direction.

[0042] As in Fig. Figure 14 illustrates that in the present embodiment, the ring 55 comes into contact with the first end face 31 of the winding drum 3. In a case where the winding drum 3 and the locking base 4D are rotated relative to each other, the winding drum 3 and the drive wheel 5 are rotated relative to each other, while the ring 55 comes into contact with the first end face 31 of the winding drum 3 in the axial direction of the winding drum 3, and while an outer circumference of the flange 53 of the drive wheel 5 comes into contact with the folded section 3Ba of the bearing 3B, which is attached to the winding drum 3, in a radial direction of the winding drum.

[0043] As in the Fig. 10 and Fig. Figure 14 illustrates an annular flange 56 projecting from an inner circumferential surface of the main body section 51. The flange 56 is a section that comes into contact with the stop element 4C. In this way, it is possible to ensure a large contact area between the flange 56 and the stop element 4C by bringing the stop element 4C into contact with the flange 56 of the drive wheel 5, instead of with a stepped section (proximal end section 72b, which will be described later) of the main body 6 of the locking base.

[0044] In an emergency, the belt tensioner 1C rotates the winding drum 3 in the winding direction via the locking base 4D and the impact energy absorption element 4A by rotating the drive wheel 5 in the winding direction of the winding drum 3. As shown in the Fig. As shown in Figures 2 to 4, the belt tensioner 1C has a belt tensioner housing 11 attached to the first side wall 21 of the housing 2, a tube 12 extending from the belt tensioner housing 11 and being bent, a movement element 13 arranged in the tube 12, and a gas generator 18 arranged in a distal section of the tube 12.

[0045] In the present embodiment, the moving element 13 has the form of a rod and is plastically deformed by the engagement of the teeth 52 of the drive wheel 5. However, the moving element 13 can be realized by a plurality of segmented bodies (for example, spheres) arranged at the same intervals as the teeth 52 of the drive wheel 5. In a vehicle emergency, the moving element 13 engages with the teeth 52 of the drive wheel 5 while being forced out of the tube 12 by the gas generated in the gas generator 18, and rotates the drive wheel 5 in the winding direction. As the drive wheel 5 rotates, the locking base main body 6, the impact energy absorption element 4A, and the winding drum 3 also rotate.Once the belt tensioner 1C is activated, the gas pressure in the tube 12 prevents the moving element 13 from being pushed back into the tube 12, thus preventing the drive wheel 5 from being rotated in the extension direction.

[0046] As in the Fig. 2 and Fig. As shown in Figure 5, the belt tensioner housing 11 is provided with an opening 11a through which the locking base body 6 is inserted, and the opening 11a has an internal toothing 11b formed on a circumferential edge of the opening 11a. On the other hand, the locking base body 6 has a locking element 61 configured to engage with the internal toothing 11b. The locking element 61 is configured to engage with the internal toothing 11b to prevent the locking base 4D from rotating in the extension direction in the event of a vehicle emergency.

[0047] As in the Fig. 9, Fig. 11 and Fig. As shown in Figure 12, the locking base main body 6 comprises a first base element 7, to which the drive wheel 5 is attached, and a second base element 8, which is attached to the first base element 7 on one side of the first base element 7 opposite the winding drum 3, without being rotatable relative to the first base element. The locking element 61 is held between the first base element 7 and the second base element 8.

[0048] In particular, the first basic element 7 has a disk-shaped first main body section 71 and a projecting section 72 that projects from the first main body section 71 in a right-hand direction. As in Fig. As shown in Figure 3, the drive wheel 5 is arranged between the first main body section 71 and the first end face 31 of the winding drum 3, and the projecting section 72 penetrates the drive wheel 5. In other words, the projecting section extends from a section of the locking base 4D, which is positioned on a side of the winding drum 3 opposite the drive wheel 5, towards the winding drum 3. A right-hand section of the projecting section 72, with respect to the flange 56 of the drive wheel 5, forms the shaft section 72a of the locking base 4D. In other words, the shaft section 72a is formed in a distal end face of the projecting section 72.

[0049] The external thread 73 is formed on an outer circumferential surface of a distal end face of the projecting section 72. The projecting section 72 includes, on a proximal side of the external thread 83, a proximal end section 72b that projects radially outward beyond the external thread 73. A proximal end section 72b of the projecting section 72 is configured to have a hexagonal cross-sectional shape. The fitting opening of the main body section 51 of the drive wheel 5 is also configured to have a hexagonal cross-section, and by fitting the proximal end section 72b into the fitting opening, the drive wheel 5 is attached to the first base element 7 without being rotatable relative to the first base element 7. However, the proximal end section 72b of the projecting section 72 may be configured to have a non-circular cross-sectional shape, such as polygonal, other than hexagonal.The fitting opening of the main body section 51 of the drive wheel 5 is also designed such that it has a non-circular cross-sectional shape, and by fitting the proximal end section 72b into the fitting opening, the drive wheel 5 is attached to the first base element 7 without being rotatable relative to the first base element 7.

[0050] The first base element 7 has a first recess 74, which is recessed from a distal end face of the projecting section 72, and a second recess 75, which is coaxial with the first recess 74 and recessed from a surface of the first main body section 71 on a side opposite the drive wheel 5. The first recess 74 is a wedge-shaped recess for coupling with the coupling section 42 of the impact energy absorption element 4A, and the coupling section 42 is fitted into the first recess 74. In the present embodiment, the second recess 75 has a circular cross-sectional shape. In the present embodiment, the first base element 7 includes a separating element 76 that separates the first recess 74 and the second recess 75 from each other. In other words, the first recess 74 and the second recess 75 are provided with a bottom.

[0051] The second base element 8 comprises a plate-shaped second main body section 81, which overlaps the first main body section 71, and a fitting projection 82, which projects from the second main body section 81 in a right-hand direction. In the present embodiment, the second main body section 81 has three concave engagement sections 87, and by the engagement of the three convex engagement sections 79 provided on the first main body section 71 with the respective concave engagement sections 87, the second base element 8 is attached to the first base element 7 without being rotatable relative to the first base element 7. The fitting projection 82 has a circular cross-sectional shape, and the fitting projection 82 is fitted into the second recess 75.The second recess 75 and the first fitting projection 82 can have a non-circular cross-sectional shape, and by fitting the fitting projection 82 into the second recess 75, the second base element 8 can be attached to the first base element 7 without being rotatable relative to the first base element. In this case, the concave engagement sections 87 and the convex engagement sections 79 can be omitted.

[0052] In the present embodiment, the second main body section 81 of the second base element 8 has three crimp projections 85 that project to the right, whereas the first main body section 71 of the first base element 7 is provided with three through-holes 77 through which the crimp projections 85 are inserted. A concave crimp section 78, which is coaxial with the through-hole 77 and has a larger diameter than the through-hole 77, is formed on one side of the first main body section 71 opposite the second main body section 81. A portion of each crimp projection 85 that projects from the through-hole 77 is crimped to have a larger diameter than the through-hole 77 in the concave crimp section 78 and an outer diameter that is substantially equal to an inner diameter of the concave crimp section 78 (in the Fig. 11 and Fig. 12 shows the crimp protrusion 85 in a form before crimping).

[0053] The locking element 61 comprises an essentially arc- and plate-shaped main body section 62, which is held by the first main body section 71 of the first base element 7 and the second main body section 81 of the second base element 8, a plurality of (in the illustrated example three) engagement teeth 63 formed on an outer side surface of the main body section 62 and configured such that they can engage with the internal toothing 11b, and an actuating shaft 64 projecting from the main body section 62 in the direction to the left.

[0054] The second main body section 81 of the second base element 8 has a pin 84 that projects to the left. The return spring 9A has an essentially arc-shaped form, as shown in Fig. Figure 7 shows that the return spring 9A has one end that engages with the actuating shaft 64 of the locking element 61 and the other end that engages with the pin 84. The return spring 9A is configured such that it holds the locking element 61 in a position that Fig. The non-intervention position shown in 13A is maintained.

[0055] The second base element 8 is provided with an engagement opening 83, which is coaxial with the fitting projection 82 and opens to the left. In the present embodiment, the engagement opening 83 penetrates the second base element 8 and is also open in the direction to the right. The engagement opening 83 has a hexagonal cross-sectional shape.

[0056] The locking element 61 is actuated by a synchronized gear 14 (see Fig. 2 and Fig. 7). As in Fig. As shown in Figure 2, the locking unit 1D has a cover element 17 which accommodates the synchronized gear 14 and a vehicle sensor 16. The synchronized gear 14 has a seatbelt sensor 15. The seatbelt sensor 15 is configured to be activated when the seatbelt 10 is rapidly extended, thus preventing the synchronized gear 14 from rotating in the extension direction. The vehicle sensor 16 is configured to be activated when the vehicle's acceleration changes sharply, thus preventing the synchronized gear 14 from rotating in the extension direction.

[0057] In a case where the synchronized gear 14 is prevented from being rotated in the extension direction, the locking base 4D together with the winding drum 3 is rotated relative to the synchronized gear 14, and the actuating shaft 64 of the locking element 61 is inserted into a guide opening 14a (see Fig. 7) of the synchronized gear 14 is actuated, causing the locking element 61 to move away from the in Fig. 13A non-intervention position in a Fig. The intervention position shown in 13B has been moved.

[0058] As in Fig. As shown in Figure 7, the rotating shaft 9B comprises a rod-shaped main body section 91 and an arm 92 extending radially outward from the main body section 91. A right-hand section of the main body section 91 has a hexagonal cross-sectional shape, and this right-hand section is fitted into and engages with the engagement opening 83 of the second base element 8. The arm 92 serves to retain the return spring 9A, and a hook 93, provided at a distal end of the arm 92, engages in an engagement opening 88 provided in the second main body section 81 of the second base element 8. As shown in Figure 7, the main body section 91 is formed by the arm 92. Fig. As shown in Figure 3, a left-hand section of the rotary shaft 9B penetrates the synchronized gear 14 and is rotatably mounted by the cover element 17 of the locking unit 1D.

[0059] As described above, in the present embodiment of the seat belt retractor 1, the ring 55 around which the impact energy absorption wire 4B is wound is configured to be rotatable relative to the winding drum 3, thus enabling the impact energy absorption wire 4B to stably absorb the impact energy. The stop element 4C is configured to be movable while radially within the ring 55, thereby allowing a reduction in the dimension of the locking base 4D in the axial direction of the winding drum 3. Consequently, the size of the seat belt retractor 1 can be reduced in the axial direction of the winding drum 3.

[0060] In the present embodiment, at least part of the external thread 73 formed on the shaft section 72a of the locking base 4D is located radially inside the ring 55, so that the shaft section 72a can be easily shortened.

[0061] In the present embodiment, the locking base 4D includes the drive wheel 5, so that the dimension of the locking base 4D in the axial direction of the winding drum 3 in the safety belt retractor 1 including the belt tensioner 1C can be easily reduced.

[0062] Furthermore, in the present embodiment, the stop element 4C, which is configured to be movable while radially inside the ring 55, comes into contact with the drive wheel 5, so that the dimension of the locking base 4D in the axial direction of the winding drum 3 can be easily reduced. <modifikation>

[0063] The foregoing description of the embodiments of the present invention serves for illustration and description purposes. It is not intended to be exhaustive or to limit the invention to the exact forms disclosed. Naturally, many modifications and variations are obvious to a person skilled in the art. The embodiments have been selected and described to explain the principles of the invention and its practical applications as effectively as possible, thereby enabling other persons skilled in the art to understand the invention in various embodiments and with the various modifications suitable for the respective application. It is noted that the scope of protection of the invention is defined by the following claims and their equivalents.

[0064] For example, the impact energy absorption element 4A is not limited to the torsion bar, as long as the impact energy is absorbed during the relative rotation between the winding drum 3 and the locking base 4D. The impact energy absorption element 4A can, for example, be a wire or the like, which is bent and deformed by the relative rotation between the winding drum 3 and the locking base 4D in order to absorb the impact energy.

[0065] As with a winding drum unit 1Ba according to a first in Fig. In the modification shown in Figure 16, the ring 55, around which the impact energy absorption wire 4B is wound, can be separated from the locking base 4D. In this way, when the ring 55 is separate from the locking base 4D, the shape and material of the ring 55 can be easily optimized. Therefore, the cost and weight of the seatbelt retractor 1 can be easily reduced. However, when the ring 55 is integrated with the locking base 4D, as in the embodiment above, the number of components can be reduced.

[0066] The winding drum unit 1Ba according to the in Fig. In the first modification shown in Figure 16, the ring 55 is attached to the drive wheel 5 of the locking base 4D without being rotatable relative to the drive wheel 5. In the first modification, which is shown in the Fig. 16 and Fig. As shown in Figure 17, a section of the drive wheel 5, which faces the first end face 31 of the winding drum 3, comprises a concave support section 57 that is recessed in the axial direction of the winding drum 3. A left end section, which is part of the ring 55, is inserted into the concave support section 57. Although in Fig. Not shown in Figure 17, an engagement structure is provided to prevent the relative rotation between the drive wheel 5 and the ring 55 at the concave support section 57 and the left end section of the ring 55.

[0067] In the first modification, the radial movement of the ring 55 is restricted by the concave support section 57, thus preventing unexpected contact due to radial movement. This includes, for example, contact between an inner circumferential surface of the ring 55 and the stop element 4C, and contact between the impact energy absorption wire 4B, wound around an outer circumferential surface of the ring 55, and a section of the winding drum 3 located radially outside the ring 55. Therefore, the influence of friction on impact energy absorption can be easily reduced.

[0068] Alternatively, as in a winding drum unit 1Bb according to a second in Fig. In the modification shown in Figure 18, the ring 55, separated from the locking base 4D, is configured to be rotatable relative to the locking base 4D. In this case, there is a possibility that, due to friction between the first end face 31 of the winding drum 3 and the ring 55, the ring 55 will rotate in the same direction as the winding drum 3 at the time the impact energy is absorbed. However, when the impact energy is absorbed, friction occurs between the outer circumferential surface of the ring 55 and the impact energy absorption wire 4B, which is wound around the outer circumferential surface of the ring 55. The friction between the outer circumferential surface of the ring 55 and the impact energy absorption wire 4B increases as the impact energy absorption wire 4B is wound, thus preventing the ring 55 from rotating in the same direction as the winding drum 3 and allowing it to rotate relative to the winding drum 3.Therefore, as in the embodiment above, the impact energy absorption wire 4B can also stably absorb the impact energy in a case where the ring 55 is rotatable relative to the locking base 4D. If the ring 55 is rotatable relative to the locking base 4D, a structure for attaching the ring 55 can be simplified, thus saving space.

[0069] In the winding drum unit 1Bb according to the in Fig. In the second modification shown in Figure 18, a section of the drive wheel 5 facing the first end face 31 of the winding drum 3 is not provided with the concave support section 57 (see Figure 18). Fig. 16), and the ring 55 comes into contact with a flat right side surface of the drive wheel 5.

[0070] As in a winding drum unit 1Bc according to a third modification, which is in Fig. As shown in Figure 19, even in a case where the ring 55 is configured to be rotatable relative to the locking base 4D, a section of the drive wheel 5 facing the first end face 31 of the winding drum 3 can be provided with the concave support section 57. That is, in the winding drum unit 1Bc according to the third modification, the concave support section 57 is provided similarly to that in the first modification, but no engagement structure is provided to prevent relative rotation between the drive wheel 5 and the ring 55 at the concave support section 57 and the left end section of the ring 55. In other words, the shapes of the concave support section 57 and the left end section of the ring 55 are exactly as in Figure 19. Fig. Figure 17 illustrates this. In this case, the radial movement of the ring 55 is restricted by the concave support section 57, thus preventing unexpected contact due to radial movement of the ring 55, such as contact between the inner circumferential surface of the ring 55 and the stop element 4C, or contact between the impact energy absorption wire 4B, wound around the outer circumferential surface of the ring 55, and a section of the winding drum 3 located radially outside the ring 55. Therefore, the influence of friction on impact energy absorption can be easily reduced.

[0071] The winding drum unit 1Bc according to the in Fig. In the third modification shown in Figure 19, the flange 53 of the drive wheel 5 comes into contact with the first end face 31 of the winding drum 3 in the axial direction of the winding drum 3. The height of the ring 55 in the axial direction of the winding drum 3 is less than the distance (i.e., the distance from the first end face 31 to the bottom of the concave support section 57) between the winding drum 3 and the drive wheel 5 at the position where the ring 55 is present. Therefore, friction between the first end face 31 of the winding drum 3 and the ring 55 is less likely to occur at the time of impact energy absorption, and the ring 55 can be easily rotated relative to the winding drum 3, thus reducing the influence of friction on impact energy absorption.

[0072] Alternatively, as in a winding drum unit 1Bd according to a fourth modification, which in Fig. Figure 20 shows that, in a case where the ring 55 is configured to be rotatable relative to the locking base 4D, a section of the drive wheel 5 facing the first end face 31 of the winding drum 3 is provided with a convex support section 58 projecting in the axial direction of the winding drum 3. The thickness of the convex support section 58 is less than the thickness of the ring 55 in the radial direction of the winding drum 3. The left end section of the ring 55 includes a concave section 55a into which the convex support section 58 can be inserted, and the convex support section 58 is inserted into the ring 55.

[0073] According to the configuration, the movement of the ring 55 in the radial direction is restricted by the convex support section 58, thus preventing unexpected contact due to the movement of the ring 55 in the radial direction, such as contact between an inner circumferential surface of the ring 55 and the stop element 4C, or contact between the impact energy absorption wire 4B, which is wound around the outer circumferential surface of the ring 55, and a section of the winding drum 3 located radially outside the ring 55. Therefore, the influence of friction on impact energy absorption can be easily reduced.

[0074] As in a fifth modification, which in Fig. As shown in Figure 21, the proximal end section 72b of the preceding section 72 can extend to the right side of the first base element 7 (one side of the shaft section 72a in which the external threads 73 are provided) without an annular flange 56 being provided on the inner circumferential surface of the main body section 51 of the drive wheel 5. In this case, the stop element 4C is configured such that it comes into contact with the proximal end section 72b instead of the flange 56, and the stop element 4C moves into the position where it comes into contact with the proximal end section 72b.Therefore, during the relative rotation of the winding drum 3 and the locking base 4D, the stop element 4C moves from a position where it separates from the proximal end section 72b of the protruding section 72 to a position where it comes into contact with the proximal end section 72b of the protruding section 72, thereby limiting the relative rotation of the winding drum 3 and the locking base 4D to a predetermined extent. In other words, the stop element 4C is prevented from moving in the axial direction of the winding drum 3 by coming into contact with the proximal end section 72b of the protruding section 72. As a result, the stop element 4C, which is moved radially inside the ring 55, comes into contact with the proximal end section 72b, and a dimension of the locking base 4D in the axial direction of the winding drum 3 is reduced in a simple way.In relation to . Fig. 21 However, the right end of the proximal end section 72b of the preceding section 72 and the right edge of the pass opening of the drive wheel 5 can be aligned with each other, and the stop element 4C can come into contact with both the proximal end section 72b of the preceding section 72 and the drive wheel 5.

[0075] The belt tensioner 1C and the drive wheel 5 can be omitted. In this case, the first base element 7 can be provided with a flange facing the first end face 31 of the winding drum 3, and the flange can be provided with the retaining sections 54. Furthermore, in a case where no belt tensioner 1C is present, the insertion opening 21a of the first side wall 21 of the housing 2 can have internal teeth 11b formed on a circumferential edge thereof, and the locking element 61 can engage with the internal teeth 11b in a vehicle emergency.

[0076] Furthermore, the locking base 4D can be provided with external teeth, and a locking element engaging with the external teeth can be provided on the first side wall 21 of the housing 2. <schlussfolgerung>

[0077] In a first aspect, the present disclosure provides a seatbelt retractor which has: a case with a pair of side walls facing each other; a winding drum configured to wind up a webbing, wherein the winding drum is received between the pair of side walls to be rotatable in a winding direction and an extension direction of the webbing, wherein the winding drum has a central opening which opens into at least a first end face; a locking base arranged such that it faces the first end face of the winding drum, wherein the locking base is prevented from being rotated in the extension direction in an emergency of the vehicle, wherein an external thread is formed coaxially with the winding drum on an outer circumferential surface of a shaft section of the locking base; an impact energy absorption element having one end face coupled to the winding drum and another end face coupled to the locking base, wherein the impact energy absorbing element connects the winding drum and the locking base such that they are integrally rotatable in a normal state, and wherein the impact energy absorbing element is configured to plastically deform in a case where a webbing pull-out force exceeds a predetermined value in a state where rotation of the locking base in the pull-out direction to absorb impact energy is prevented, while allowing relative rotation between the winding drum and the locking base; an impact energy absorption wire received in a slot provided in the winding drum to form an opening in the first end face of the winding drum, wherein a head section of the impact energy absorption wire projecting from the opening of the slot is attached to the locking base, wherein the impact energy absorption wire is configured to be pulled out of the opening while plastically deformed in a case where the winding drum and the locking base are rotated relative to each other in order to absorb the impact energy; a ring that is integral with or separate from the locking base, wherein the ring is configured to be rotatable coaxially relative to the winding drum, and wherein the impact energy absorption wire drawn out of the opening is wound around an outer circumference of the ring; and a stop element which is held in the central opening without being rotatable relative to the winding drum and which is movable in an axial direction of the winding drum, wherein the stop element is screwed onto the external thread of the locking base and the stop element is configured such that it defines a permissible degree of relative rotation between the winding drum and the locking base in a case where the impact energy absorption element absorbs the impact energy, the stop element can be configured such that it is movable while located radially inside the ring.

[0078] According to the configuration above, the ring around which the impact energy absorption wire is wound is configured to rotate relative to the winding drum, thus enabling the impact energy absorption wire to stably absorb the impact energy. Furthermore, the stop element is configured to be movable while radially within the ring, allowing a reduction in the dimension of the locking base in the axial direction of the winding drum. Therefore, the size of the seatbelt retractor can be reduced in the axial direction of the winding drum.

[0079] Secondly, in accordance with the first aspect, the locking base includes an annular projection that extends towards the first end face of the winding drum, and the ring can be the annular projection itself. According to the configuration, the ring is integrated into the locking base, thus reducing the number of components.

[0080] As a third aspect, in addition to the first, the ring can be separate from the locking base, with the ring attached to the locking base but not rotatable relative to it. This configuration allows for easy optimization of the ring's shape and material. Therefore, the cost and weight of the seatbelt retractor can be easily reduced.

[0081] As a fourth aspect, following the first, the ring can be separate from the locking base, configured to rotate relative to the locking base. This configuration allows for easy optimization of the ring's shape and material. Consequently, the cost and weight of the seatbelt retractor can be easily reduced. The ring's rotatable design also simplifies the ring's mounting structure and saves space.

[0082] As a fifth aspect, in accordance with the fourth aspect, the locking base can have a concave support section on a section facing the first end face of the winding drum, with the concave support section being excluding the axial direction of the winding drum, and a portion of the ring can be inserted into the concave support section. According to this configuration, the movement of the ring in the radial direction is restricted by the concave support section, thus preventing unexpected contact due to radial movement of the ring, such as contact between an inner circumferential surface of the ring and the stop element, and such as contact between the impact energy absorption wire wound around an outer circumferential surface of the ring and a section of the winding drum located radially outside the ring.Therefore, the influence of friction on impact energy absorption can be reduced in a simple way.

[0083] As a sixth aspect, in accordance with the fourth aspect, the locking base can have a convex support section on a section facing the first end face of the winding drum. This convex support section projects axially from the winding drum and can be inserted into the interior of the ring. According to this configuration, the convex support section restricts the radial movement of the ring, thus preventing unexpected contact due to radial movement. This includes, for example, contact between the inner circumferential surface of the ring and the stop element, and contact between the impact energy absorption wire wound around the outer circumferential surface of the ring and a portion of the winding drum located radially outside the ring.Therefore, the influence of friction on impact energy absorption can be reduced in a simple way.

[0084] As a seventh aspect, in accordance with one of the first to sixth aspects, at least part of the external thread of the shaft section can be arranged radially inside the ring. According to this configuration, the shaft section of the locking base can be easily shortened.

[0085] As an eighth aspect according to one of the first to seventh aspects, the locking base can include a drive wheel facing the first end face of the winding drum. The seat belt retractor can further include a belt tensioner configured to rotate the drive wheel in the winding direction of the winding drum in the event of a vehicle emergency, thus rotating the winding drum over the locking base and the impact energy absorption element in the winding direction. The ring can be provided between the first end face of the winding drum and the drive wheel. According to this configuration, the dimension of the locking base in the axial direction of the winding drum is easily reduced in the seat belt retractor, including the belt tensioner.

[0086] As a ninth aspect, in accordance with the eighth aspect, the stop element can be prevented from moving in the axial direction of the winding drum by contacting the drive wheel. According to the configuration, the movable stop element, arranged radially inside the ring, comes into contact with the drive wheel, thus easily reducing the dimension of the retaining ring in the axial direction of the winding drum.

[0087] As a tenth aspect, according to the eighth or ninth aspect, the locking base may have a projecting section, wherein the projecting section extends towards the winding drum from a section of the locking base that is positioned on a side of the winding drum opposite the drive wheel, the projecting section is formed with the shaft section on a distal end side of the projecting section, the projecting section has a proximal section on a proximal side of the external thread that extends radially further outwards than the external thread, and the stop element is prevented from being moved in the axial direction of the winding drum by coming into contact with the proximal section.According to the configuration, the stop element, which is movable while radially inside the ring, comes into contact with the proximal end section of the protruding section, thus reducing the dimension of the locking base in the axial direction of the winding drum in a simple way. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2020-104777A [0003, 0004, 0006, 0010, 0011]< / schlussfolgerung> < / modifikation>

Claims

[1] Safety belt retractor, comprising: a housing having a pair of side walls facing each other; a winding drum configured to wind a webbing, the winding drum being received between the pair of side walls so as to be rotatable in a winding direction and a withdrawal direction of the webbing, the winding drum having a central opening opening into at least a first end face; a locking base arranged to face the first end surface of the winding drum, the locking base being prevented from being rotated in the extension direction in an emergency of the vehicle, an external thread being formed on an outer peripheral surface of a shaft portion of the locking base coaxial with the winding drum; an impact energy absorption member having one end coupled to the winding drum and the other end coupled to the locking base, wherein the impact energy absorption member connects the winding drum and the locking base so as to be integrally rotatable in a normal state, and wherein the impact energy absorption member is configured to be plastically deformed when a pull-out force of the webbing exceeds a predetermined value in a state where the locking base is prevented from being rotated in the pull-out direction to absorb impact energy while allowing relative rotation between the winding drum and the locking base; an impact energy absorption wire received in a slot provided in the winding drum to form an opening in the first end surface of the winding drum, wherein a head portion of the impact energy absorption wire protruding from the opening of the slot is fixed to the locking base, wherein the impact energy absorption wire is configured to be pulled out from the opening while being plastically deformed in a case where the winding drum and the locking base are relatively rotated to absorb the impact energy; a ring provided integrally with or separately from the locking base, the ring being configured to be coaxially rotatable relative to the winding drum, the impact energy absorption wire drawn out of the opening being wound around an outer periphery of the ring; and a stop member held in the central opening without being rotatable relative to the winding drum and movable in an axial direction of the winding drum, wherein the stop member is screwed onto the external thread of the locking base, and the stop member is configured to define a permissible degree of relative rotation between the winding drum and the locking base in a case where the impact energy absorption member absorbs the impact energy, wherein the stop member is configured to be movable while located radially within the ring. [2] Safety belt retractor according to claim 1, wherein the locking base has an annular projection projecting toward the first end face of the winding drum, and the ring is the annular recess. [3] Safety belt retractor according to claim 1, wherein the ring is separate from the locking base, wherein the ring is fixed to the locking base without being rotatable relative to the locking base. [4] Safety belt retractor according to claim 1, wherein the ring is separate from the locking base, wherein the ring is configured to be rotatable relative to the locking base. [5] Safety belt retractor according to claim 4, wherein the locking base has a concave support portion at a portion facing the first end face of the winding drum, the concave support portion being recessed in the axial direction of the winding drum, and a part of the ring is inserted into the concave support section. [6] Safety belt retractor according to claim 4, wherein the locking base has a convex support portion at a portion facing the first end face of the winding drum, the convex support portion protruding in the axial direction of the winding drum, and the convex support section is inserted into the ring. [7] Safety belt retractor according to one of claims 1 to 6, wherein at least a part of the external thread of the shaft portion is located radially inside the ring. [8] Safety belt retractor according to one of claims 1 to 7, wherein the locking base has a drive wheel facing the first end face of the winding drum, the seat belt retractor further comprises a belt pretensioner configured to rotate the drive wheel in the winding direction of the winding drum in a vehicle emergency to rotate the winding drum in the winding direction via the locking base and the impact energy absorption member, and the ring is provided between the first end face of the winding drum and the drive wheel. [9] Safety belt retractor according to claim 8, wherein the stop member is prevented from being moved in the axial direction of the winding drum by coming into contact with the drive wheel. [10] Safety belt retractor according to claim 8 or 9, wherein the locking base has a protruding portion, the protruding portion protruding toward the winding drum from a portion of the locking base positioned on an opposite side of the winding drum with respect to the drive wheel, the protruding portion being formed with the shaft portion in a distal end side of the protruding portion, the projecting portion on a proximal side of the external thread has a proximal portion which projects radially further outward than the external thread, and the stop member is prevented from being moved in the axial direction of the winding drum by coming into contact with the proximal portion.

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