seat belt retractor

Abstract

To provide a seat belt retractor which can increase the number of sensor mounting angles that are adjustable by one sensor holder than a conventional seat belt retractor.SOLUTION: A seat belt retractor includes a vehicle acceleration sensor 4 and a winding drum. The vehicle acceleration sensor 4 includes a sensor holder 5 having a mounting surface 51 on which an inertial mass body 41 is mounted, and a mounting member 8 to which the sensor holder 5 is coupled. The mounting member 8 is mounted on a housing of the seat belt retractor in a state where the sensor holder 5 is in any one of a first attitude and a second attitude inverted around a central line of the mounting surface 51 with respect to the first attitude. The sensor holder 5 can be coupled to the mounting member 8 at any one of a plurality of angle positions, which is a position rotated around a rotation shaft 50. The first attitude and the second attitude have a plurality of different sensor mounting angles which corresponds to the plurality of angle positions and is the angles of the central line of the mounting surface 51 with respect to the housing.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a seat belt retractor that is mounted on a vehicle and that retracts and unwinds a webbing that serves as a seat belt. [Background technology]

[0002] Conventionally, seat belt retractors have been known that include a vehicle acceleration sensor that enters a detection state when the vehicle acceleration exceeds a predetermined value, and that prevents the webbing from being pulled out when the vehicle acceleration sensor enters the detection state.

[0003] For example, Patent Document 1 discloses a seat belt retractor 100 as shown in Fig. 19. This seat belt retractor 100 includes a housing 110 having a pair of side plates and a back plate, a take-up drum 120 housed between the side plates of the housing 110 so as to be rotatable in the webbing unwinding direction and the webbing winding direction, and a vehicle acceleration sensor 130 attached to one of the side plates of the housing 110.

[0004] The vehicle acceleration sensor 130 includes a spherical inertial mass body 140, a sensor holder 150 having a mounting surface 151 on which the inertial mass body 140 is placed, and a sensor lever 160 that is swingably supported by the sensor holder 150. When the acceleration of the vehicle reaches or exceeds a predetermined value, the sensor lever 160 is pushed up by the inertial mass body 140 that rolls on the mounting surface 151. This prevents the take-up drum 120 from rotating in the webbing unwinding direction.

[0005] Furthermore, the vehicle acceleration sensor 130 includes a mounting member 170 to which the sensor holder 150 is coupled and which is attached to one side plate of the housing 110 .

[0006] A seat belt retractor may be mounted on a vehicle in a state inclined in the longitudinal direction and / or width direction of the vehicle. The seat belt retractor 100 disclosed in Patent Document 1 is configured so that the mounting surface 151 of the sensor holder 150 can be made closer to horizontal even when the axial direction of the winding drum 120 is inclined with respect to the horizontal plane. In other words, the inclination of the sensor holder 150 is adjusted along a plane parallel to the back plate of the housing 110.

[0007] Specifically, sensor holder 150 can be coupled to mounting member 170 at any one of a plurality of angular positions, which are positions rotated about rotation axis 152 extending in a direction perpendicular to the back plate of housing 110. Mounting member 170 is provided with fixed-side engaging portion 171 including a plurality of engaging teeth arranged in the circumferential direction about rotation axis 152, and sensor holder 150 is provided with movable-side engaging portion 153 that can engage with fixed-side engaging portion 171 and includes a plurality of engaging teeth arranged in the circumferential direction about rotation axis 152. Then, by changing the engagement state between movable-side engaging portion 153 and fixed-side engaging portion 171, sensor holder 150 is coupled to mounting member 170 at any one of the plurality of angular positions.

[0008] Furthermore, Patent Document 2 discloses a seat belt retractor 100 that has an engagement structure similar to that of the above-mentioned seat belt retractor 100 and is configured to accommodate a state in which the axial direction of the winding drum is tilted relative to the horizontal plane (in Patent Document 2, a state in which the seat belt retractor is tilted in the width direction of the vehicle). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] China Utility Model Publication No. 201856732 [Patent Document 2] Patent No. 5515180 Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the case of the seat belt retractor 100 of Patent Document 1, in which the engagement portions 171, 153 having a plurality of engagement teeth engage with each other, the sensor mounting angle, which is the angle of the center line of the mounting surface 151 relative to the housing 110, can only be adjusted by the pitch (spacing) of the engagement teeth. Therefore, if it is desired to adjust the sensor mounting angle to an angle between the pitches of the engagement teeth, it is necessary to prepare another sensor holder 150 with a shifted pitch of the engagement teeth.

[0011] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a seat belt retractor that can adjust the sensor mounting angle with a single sensor holder to a greater extent than in the past. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention provides a vehicle acceleration sensor that enters a detection state when the acceleration of the vehicle reaches or exceeds a predetermined value, and a take-up drum that is accommodated in a housing so as to be rotatable in the webbing unwinding direction and the webbing winding direction, and that prevents the rotation of the webbing in the unwinding direction when the vehicle acceleration sensor enters the detection state. The vehicle acceleration sensor includes a spherical inertial mass body, a sensor holder that is a mounting surface on which the inertial mass body is placed, the sensor holder having a cone-shaped mounting surface with a cross-sectional shape symmetrical about its center line, and a sensor lever that is swingably supported by the sensor holder, and that is pushed up by the inertial mass body that rolls on the mounting surface when the acceleration of the vehicle reaches or exceeds the predetermined value. and an attachment member to which the sensor holder is coupled and attached to the housing, wherein the attachment member is attached to the housing with the sensor holder in either a first position or a second position that is inverted from the first position around the center line of the mounting surface, and the sensor holder can be coupled to the attachment member in any of a plurality of angular positions, which are positions rotated around a rotation axis extending in a direction perpendicular to the center line of the mounting surface, in each of the first position and the second position, and a plurality of sensor attachment angles, which are angles of the center line of the mounting surface relative to the housing, corresponding to the plurality of angular positions, are different between the first position and the second position.

[0013] According to the above configuration, the sensor mounting angle differs between when the sensor holder is in the first position and when it is in the second position, so the number of sensor mounting angles that can be adjusted with one sensor holder can be increased compared to conventional methods. Therefore, when the sensor mounting angle is adjustable within a predetermined angle range, the number of sensor holders that need to be prepared can be reduced.

[0014] For example, the sensor holder may be provided with an outward engaging portion including at least one outward protrusion that points radially outward around the rotation axis, and the mounting member may be provided with an inward engaging portion that is engageable with the outward engaging portion and includes at least one inward protrusion that points radially inward around the rotation axis, and one or both of the at least one outward protrusion and the at least one inward protrusion may be provided in multiples and aligned in a circumferential direction around the rotation axis, and the engagement state between the outward engaging portion and the inward engaging portion may be changed so that the sensor holder can be connected to the mounting member at any of the multiple angular positions.

[0015] The sensor holder may be in either the first position or the second position by reversing the orientation when coupled to the mounting member, and the outward engaging portion and the inward engaging portion may engage in both the first position and the second position. With this configuration, it is possible to select whether the sensor holder is in the first position or the second position depending on the orientation of the sensor holder when coupled to the mounting member.

[0016] The number of the inward engaging portion may be one, and the outward engaging portion may include a first outward engaging portion that engages with the inward engaging portion in the first position and a second outward engaging portion that engages with the inward engaging portion in the second position, and the first outward engaging portion and the second outward engaging portion may have different positions of the at least one outward protrusion when viewed from the extension direction of the rotation shaft. With this configuration, a plurality of sensor mounting angles can be easily set by changing the positions of the outward protrusion of the first outward engaging portion and the outward protrusion of the second outward engaging portion.

[0017] The number of the outward engaging portion may be one, and the inward engaging portion may include a first inward engaging portion that engages with the outward engaging portion in the first posture and a second inward engaging portion that engages with the outward engaging portion in the second posture, and the position of the at least one inward protrusion may be different between the first inward engaging portion and the second inward engaging portion when viewed from the extension direction of the rotation shaft. With this configuration, a plurality of sensor mounting angles can be easily set by changing the position of the inward protrusion of the first inward engaging portion and the inward protrusion of the second inward engaging portion.

[0018] The inward engagement portion may include a first inward engagement portion and a second inward engagement portion, and the outward engagement portion may include a first outward engagement portion that engages with the first inward engagement portion but does not engage with the second inward engagement portion in the first posture and does not engage with the first inward engagement portion and the second inward engagement portion in the second posture, and a second outward engagement portion that does not engage with the first inward engagement portion and the second inward engagement portion in the first posture and engages with the second inward engagement portion but does not engage with the first inward engagement portion in the second posture. With this configuration, the engagement structure between the first inward engagement portion and the first outward engagement portion can be made different from the engagement structure between the second inward engagement portion and the second outward engagement portion.

[0019] The mounting member may be attachable to the housing in either the first position or the second position by reversing its orientation relative to the housing. With this configuration, it is possible to select whether the sensor holder is in the first position or the second position depending on the orientation of the mounting member when attached to the housing.

[0020] The outward engaging portion may be asymmetric with respect to a plane including the rotation axis and the center line of the mounting surface. According to this configuration, the mounting member can have a symmetrical simple shape.

[0021] The sensor holder may have a first support part that supports the sensor lever so that it can swing in the first position, and a second support part that is located on the opposite side of the center line of the mounting surface from the first support part and supports the sensor lever so that it can swing in the second position. With this configuration, the sensor lever can be designed to have the same orientation in the first position and the second position.

[0022] The shape of the sensor holder may be asymmetric with respect to a plane that is perpendicular to the direction in which the first support part and the second support part are spaced apart and that includes the center line of the placement surface. With this configuration, it is possible to determine whether the sensor holder is in the first position or the second position simply by looking at the sensor holder.

[0023] The first support portion and the second support portion of the sensor holder may have different heights from the mounting surface in the direction along the center line. With this configuration, it is easy to determine whether the sensor holder is in the first position or the second position. [Effects of the Invention]

[0024] According to the present invention, the number of sensor mounting angles that can be adjusted with one sensor holder can be increased compared to conventional cases. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a perspective view of a seat belt retractor according to an embodiment of the present invention. [Figure 2] 2 is an exploded perspective view of the seat belt retractor shown in FIG. 1 as viewed from one side. FIG. [Figure 3] 2 is an exploded perspective view of the seat belt retractor shown in FIG. 1 as viewed from the other side. FIG. [Figure 4] FIG. 2 is a perspective view of the vehicle acceleration sensor in a state where the sensor holder is coupled to the mounting member at a reference angular position. [Figure 5] FIG. 5 is an exploded perspective view of the vehicle acceleration sensor shown in FIG. 4. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 10] 10(a) and 10(b) are cross-sectional views taken along lines XA-XA and XB-XB in FIG. 9, respectively. [Figure 11] (a) is an oblique view of a vehicle acceleration sensor in a state where the sensor holder is connected to the mounting member at an angular position adjacent to the reference angular position, and (b) is a cross-sectional view showing the engagement state of the inward engagement portion and the outward engagement portion at that time. [Figure 12] 11(a) is a perspective view of the vehicle acceleration sensor in a state where the sensor holder is connected to the mounting member at an angular position next to the reference angular position (opposite to FIG. 11(a)), and FIG. 11(b) is a cross-sectional view showing the engagement state of the inward engagement portion and the outward engagement portion at that time. [Figure 13] 1(a) is a perspective view of a vehicle acceleration sensor in a state where a sensor holder whose orientation relative to the mounting member is inverted is connected to the mounting member at a reference angle position, and FIG. 1(b) is a cross-sectional view showing the engagement state of the inward engaging portion and the outward engaging portion at that time. [Figure 14] 5(a) and 5(b) are diagrams schematically showing states before and after the sensor holder of the vehicle acceleration sensor used in the embodiment is inverted. [Figure 15] 10(a) and 10(b) are diagrams schematically showing states before and after the sensor holder in the vehicle acceleration sensor of the first modified example is turned over. [Figure 16] 10(a) and 10(b) are diagrams schematically showing states before and after the sensor holder in the vehicle acceleration sensor of the second modified example is turned over. [Figure 17] 10(a) and 10(b) are diagrams schematically showing states before and after the sensor holder in the vehicle acceleration sensor of the third modified example is turned over. [Figure 18] FIG. 10 is a diagram schematically illustrating a sensor holder in a vehicle acceleration sensor according to a fourth modified example. [Figure 19]FIG. 1 is a perspective view of a conventional seat belt retractor. DETAILED DESCRIPTION OF THE INVENTION

[0026] 1 to 3 show a seat belt retractor 1 according to one embodiment of the present invention. This seat belt retractor 1 is mounted on a vehicle and is used to pull out and retract a webbing as a seat belt.

[0027] Specifically, the seat belt retractor 1 includes a housing 2 having a pair of side plates 21, 22 and a back plate 23, a winding drum 3 housed between the side plates 21, 22 of the housing 2 so as to be rotatable in the webbing unwinding direction and winding direction, and a vehicle acceleration sensor 4 attached to the side plate 21 of the housing 2.

[0028] The side plates 21, 22 of the housing 2 face each other in the axial direction of the winding drum 3, and the back plate 23 is parallel to the axial direction of the winding drum 3. For ease of explanation, the axial direction of the winding drum 3 will be referred to as the left-right direction, and the thickness direction of the back plate 23 will be referred to as the front-rear direction (the side of the side plates 21, 22 will be referred to as the front, and the opposite side will be referred to as the rear). Also, as shown in Figure 1, one of the directions perpendicular to the left-right direction and the front-rear direction will be referred to as the up direction, and the other will be referred to as the down direction.

[0029] The upper front edges of the side plates 21, 22 of the housing 2 are connected to each other by a connecting bar 25. The side plates 21, 22 are provided with openings 21a, 22a, respectively, through which the winding drum 3 is inserted. The back plate 23 is provided with an opening 24 through which the winding drum 3 is exposed.

[0030] A mechanism cover 11 is attached to a side plate 21 of the housing 2, and a winding spring unit 15 (not shown in FIGS. 2 and 3) is attached to a side plate 22 of the housing 2. The mechanism cover 11 and the winding spring unit 15 rotatably support the winding drum 3. Note that the configuration of the winding spring unit 15 is well known, so a detailed description thereof will be omitted.

[0031] The take-up drum 3 has a substantially cylindrical drum body 31 and substantially disk-shaped end portions 32, 33 with a diameter larger than that of the drum body 31. The end portion 32 is a portion that fits into the opening 21a of the side plate 21 of the housing 2, and the end portion 33 is a portion that fits into the opening 22a of the side plate 22 of the housing 2.

[0032] Internal teeth 21b are formed on the periphery of the opening 21a of the side plate 21 of the housing 2. Meanwhile, although not shown, a pawl that can engage with the internal teeth 21b is held within an end portion 32 of the winding drum 3. A clutch 35 for operating the pawl is attached to the end portion 32.

[0033] The clutch 35 is generally disk-shaped and has a larger diameter than the end 32 of the take-up drum 3, and external teeth are formed on the outer circumferential surface of the clutch 35 for engagement with the vehicle acceleration sensor 4. The clutch 35 normally rotates integrally with the take-up drum 3, but in an emergency, its rotation is prevented and it rotates relative to the take-up drum 3.

[0034] An opening 21c is also provided below the opening 21a in the side plate 21 of the housing 2 to avoid interference with the vehicle acceleration sensor 4 (more precisely, a sensor lid 14, which will be described later). In this embodiment, the vehicle acceleration sensor 4 is attached to the side plate 21 via the mechanism cover 11.

[0035] The mechanism cover 11 is formed with a first housing chamber 12 that houses the clutch 35 and a second housing chamber 13 that houses most of the vehicle acceleration sensor 4. Furthermore, a sensor lid 14 is attached to the mechanism cover 11 via a hinge. The sensor lid 14 is placed over the vehicle acceleration sensor 4 after the vehicle acceleration sensor 4 has been inserted into the second housing chamber 13.

[0036] The vehicle acceleration sensor 4 enters a detection state when the acceleration of the vehicle reaches or exceeds a predetermined value. When the vehicle acceleration sensor 4 enters a detection state, an engagement pawl 74 of a sensor lever 7A (or 7B or 7C) described below engages with the external teeth of the clutch 35. This prevents the clutch 35 from rotating in the webbing unwinding direction, and the take-up drum 3 rotates relative to the clutch 35. This relative rotation causes the pawl to jump out from the end 32 of the take-up drum 3 and engage with the internal teeth 21b, preventing the take-up drum 3 from rotating in the webbing unwinding direction.

[0037] However, the structure for preventing rotation of the take-up drum 3 in the webbing unwinding direction is not limited to this embodiment and can be modified as appropriate. For example, although not shown in the drawings, a pawl may be attached to the side plate 21 of the housing 2 so as to be able to swing, instead of the end portion 32 of the take-up drum 3, and a gear that can engage with the pawl may be attached to the take-up drum 3, instead of the internal teeth 21b of the side plate 21 of the housing 2.

[0038] Next, the structure of the vehicle acceleration sensor 4 will be described with reference to Figures 4 to 11(b). The vehicle acceleration sensor 4 includes a spherical inertial mass 41, a sensor holder 5 having a mounting surface 51 on which the inertial mass 41 is placed, and a sensor lever 7A that is swingably supported by the sensor holder 5. When the vehicle acceleration sensor 4 enters a detection state, the sensor lever 7A is pushed up by the inertial mass 41 rolling on the mounting surface 51. The vehicle acceleration sensor 4 also includes a mounting member 8 to which the sensor holder 5 is coupled, and which is attached to the side plate 21 of the housing 2 via a mechanism cover 11.

[0039] 8 and 9, the mounting surface 51 of the sensor holder 5 has a cone-like cross section that is symmetrical with respect to a center line 51a of the mounting surface 51. The cross section of the mounting surface 51 may be a straight line or a curved line. The cross section of the mounting surface 51 may be the same in any direction (i.e., spherically symmetric), or may be different in the front-rear cross section and the left-right cross section.

[0040] In this embodiment, the vehicle acceleration sensor 4 is configured to be able to accommodate a state in which the axial direction of the take-up drum 3 is inclined with respect to the horizontal plane. That is, the inclination of the sensor holder 5 (the inclination of the center line 51a of the mounting surface 51) is adjusted along a plane parallel to the back plate 23 of the housing 2.

[0041] Furthermore, in this embodiment, the mounting member 8 is attached to the housing 2 with the sensor holder 5 in either the first position shown in Figures 4, 11(a) and 12(a) or the second position shown in Figure 13(a). The second position is an inverted position relative to the first position about the center line 51a of the mounting surface 51. In this embodiment, the sensor holder 5 is in either the first position or the second position by inverting the orientation when coupled to the mounting member 8.

[0042] More specifically, as shown in Figures 5 and 6, the sensor holder 5 includes a plate-shaped support portion 52 whose upper surface forms the mounting surface 51, and a first side wall 53 and a second side wall 54 located on both sides of the support portion 52 in the front-to-rear direction.

[0043] As shown in Figures 5 and 7, the mounting member 8 includes a base 81 having a flat upper surface perpendicular to the up-down direction that faces the support portion 52 of the sensor holder 5, and a first end portion 82 and a second end portion 83 located on either side of the base 81 in the front-to-back direction and extending upward beyond the base 81.

[0044] In each of the first and second attitudes, the sensor holder 5 can be coupled to the mounting member 8 at any one of a plurality of angular positions, which are positions rotated around a rotation axis 50 extending in the front-to-rear direction. As described above, the inclination of the sensor holder 5, that is, the inclination of the center line 51a of the mounting surface 51 relative to the side plate 21 of the housing 2, is adjusted along a plane parallel to the back plate 23 of the housing 2, and therefore the front-to-rear direction is also a direction perpendicular to the center line 51a of the mounting surface 51.

[0045] 9, 10(a), and 10(b), the sensor holder 5 is provided with a first outward engagement portion 61 and a second outward engagement portion 63, and the mounting member 8 is provided with a first inward engagement portion 86 and a second inward engagement portion 88. The first inward engagement portion 86 and the second inward engagement portion 88 are engageable with the first outward engagement portion 61 and the second outward engagement portion 63. The first outward engagement portion 61 is provided on the first side wall 53 of the sensor holder 5, and the second outward engagement portion 63 is provided on the second side wall 54 of the sensor holder 5. The first inward engagement portion 86 is provided on the first end portion 82 of the mounting member 8, and the second inward engagement portion 88 is provided on the second end portion 83 of the mounting member 8.

[0046] 14(a) and (b) are diagrams schematically showing the states before and after the sensor holder is inverted. As shown in Fig. 14(a), in the first position, the first outward engaging portion 61 engages with the first inward engaging portion 86, and the second outward engaging portion 63 engages with the second inward engaging portion 88. As shown in Fig. 14(b), in the second position, the first outward engaging portion 61 engages with the second inward engaging portion 88, and the second outward engaging portion 63 engages with the first inward engaging portion 86.

[0047] Shaft portions 55, 56 are provided on the first side wall 53 and the second side wall 54 of the sensor holder 5, respectively, and are centered on the rotation axis 50, and grip portions 84, 85 are provided on the first end portion 82 and the second end portion 83 of the mounting member 8, respectively. The shaft portions 55, 56 protrude in opposite directions from the first side wall 53 and the second side wall 54. By gripping the shaft portions 55, 56 with the grip portions 84, 85, the sensor holder 5 is maintained in a state coupled to the mounting member 8 (a state in which the outward engaging portions 61, 63 and the inward engaging portions 86, 88 are engaged).

[0048] As shown in Fig. 10(a), the first outward engagement portion 61 includes at least one outward protrusion 62 that points outward in the radial direction centered on the rotation shaft 50. Similarly, as shown in Fig. 10(b), the second outward engagement portion 63 includes at least one outward protrusion 64 that points outward in the radial direction centered on the rotation shaft 50. In this embodiment, a plurality of (seven in the illustrated example) outward protrusions 62 are arranged side by side in the circumferential direction centered on the rotation shaft 50, and a plurality of (seven in the illustrated example) outward protrusions 64 are arranged side by side in the circumferential direction centered on the rotation shaft 50.

[0049] 10(a), the first inward engagement portion 86 includes at least one inward protrusion 87 that points inward in the radial direction centered on the rotation shaft 50. Similarly, the second inward engagement portion 88 includes at least one inward protrusion 89 that points inward in the radial direction centered on the rotation shaft 50, as shown in Fig. 10(b). In this embodiment, a plurality of (six in the illustrated example) inward protrusions 87 are arranged side by side in the circumferential direction centered on the rotation shaft 50, and a plurality of (six in the illustrated example) inward protrusions 89 are arranged side by side in the circumferential direction centered on the rotation shaft 50.

[0050] In this embodiment, the pitch of the outward protrusions 62, 64 and the pitch of the inward protrusions 87, 89 are 18 degrees. protrusion 87,89 The number of either one of the above may be one.

[0051] In the first posture, the engagement state between the first outward engagement portion 61 and the first inward engagement portion 86 and the engagement state between the second outward engagement portion 63 and the second inward engagement portion 88 are changed, so that the sensor holder 5 is coupled to the mounting member 8 at one of a plurality of angular positions. Similarly, in the second posture, the engagement state between the first outward engagement portion 61 and the second inward engagement portion 88 and the engagement state between the second outward engagement portion 63 and the first inward engagement portion 86 are changed, so that the sensor holder 5 is coupled to the mounting member 8 at one of a plurality of angular positions. In other words, the angular difference between adjacent angular positions is equal to the pitch between the outward protrusions 62, 64 and the pitch between the inward protrusions 87, 89.

[0052] As described above, in this embodiment, there are seven outward protrusions 62, 64 and six inward protrusions 87, 89. Therefore, the number of angular positions in the first attitude and the number of angular positions in the second attitude are three, including the reference angular position and the two adjacent angular positions. At the reference angular position in the first attitude, as shown in FIGS. 10( a) and 10(b), the outward protrusions 62, 64 at both ends of the outward protrusions 62, 64 are positioned outside the inward protrusions 87, 89. At the angular position adjacent to the reference angular position in the first attitude, as shown in FIGS. 11(b) and 12(b), the two outward protrusions 62, 64 from the ends are positioned outside the inward protrusions 87, 89. The same applies to the reference angular position and the angular position adjacent to the reference angular position in the second attitude.

[0053] 10(a) and 10(b), in this embodiment, the first outward engagement portion 61 and the second outward engagement portion 63 are asymmetric with respect to a plane S1 that includes the rotation axis 50 and the center line 51a of the mounting surface 51. Therefore, the first and second attitudes have different sensor mounting angles, which are angles of the center line 51a of the mounting surface 51 relative to the housing 2 and correspond to the different angular positions.

[0054] The asymmetry described above is synonymous with the fact that, when the number of outward protrusions 62, 64 is odd, the apex of the central outward protrusion 62, 64 is not located on the plane S1 including the rotation axis 50 and the center line 51a of the mounting surface 51, and, when the number of outward protrusions 62, 64 is even, the bottom of the groove formed between the two central outward protrusions 62, 64 is not located on the plane S1 including the rotation axis 50 and the center line 51a of the mounting surface 51.

[0055] In this embodiment, the sensor mounting angle is defined as zero degrees when the center line 51a of the mounting surface 51 is parallel to the side plate 21, as positive when the center line 51a of the mounting surface 51 tilts inward from the side plate 21, and as negative when the center line 51a tilts outward. That is, in this embodiment, the sensor mounting angle is the angle of the center line 51a of the mounting surface 51 with respect to the side plate 21 of the housing 2.

[0056] In the first attitude, the sensor mounting angle is −12 degrees at the reference angle position shown in Figures 4, 10(a), and 11(b), −30 degrees at the adjacent angle position shown in Figures 11(a) and 11(b), and 6 degrees at the anti-adjacent angle position shown in Figures 12(a) and 12(b). Meanwhile, in the second attitude, the sensor mounting angle is 12 degrees at the reference angle position shown in Figures 13(a) and 13(b), and −6 degrees and 30 degrees at the adjacent and anti-adjacent angle positions.

[0057] In the first position, as shown in Figures 4 and 10(b), sensor lever 7A is used when the sensor mounting angle is -12 degrees, as shown in Figures 11(a) and 11(b), sensor lever 7B is used when the sensor mounting angle is -30 degrees, and sensor lever 7C is used when the sensor mounting angle is 6 degrees as shown in Figures 12(a) and 12(b).In the second position, as shown in Figures 13(a) and 13(b), sensor lever 7C is used when the sensor mounting angle is 12 degrees, and although not shown, dedicated sensor levers are also used when the sensor mounting angle is -6 degrees and 30 degrees.

[0058] Each of the sensor levers 7A, 7B, and 7C includes a hollow fulcrum portion 71 that is passed through the oscillating shaft 42 (see Figure 5), an arm portion 72 that extends in the front-to-rear direction from the fulcrum portion 71, a dish portion 73 that is provided at the tip of the arm portion 72 and that covers the inertial mass body 41 on the side opposite the mounting surface 51, and an engagement claw 74 that protrudes upward from the dish portion 73.

[0059] More specifically, in all of the sensor levers 7A, 7B, and 7C, the center line of the engagement pawl 74 is substantially parallel to the perpendicular line to the upper surface of the base 81 of the mounting member 8 (i.e., the side plate 21) so that the engagement pawl 74 can engage with the external teeth of the clutch 35. The tip of the engagement pawl 74 is curved, and in this embodiment, the sensor lever including the engagement pawl 74 can be used as long as the center line of the engagement pawl 74 is within a range of ±3 degrees with respect to the perpendicular line to the upper surface of the base 81 of the mounting member 8. In this embodiment, the angular difference between adjacent angular positions exceeds the range in which the sensor lever can be used, and therefore, as described above, when changing the sensor mounting angle in each of the first and second positions, the sensor lever must be rearranged.

[0060] The sensor holder 5 includes a first support portion 58 that swingably supports the sensor lever (7A, 7B, or 7C) in the first position, and a second support portion 57 that swingably supports the sensor lever (sensor lever 7C at the reference angle position) in the second position. The second support portion 57 is located on the opposite side of the center line 51a of the mounting surface 51 from the first support portion 58.

[0061] In this embodiment, the first support portion 58 is composed of a pair of support posts 58a protruding parallel to the center line 51a of the mounting surface 51 from both end portions of the second side wall 54, and the second support portion 57 is composed of a pair of support posts 57a protruding parallel to the center line 51a of the mounting surface 51 from both end portions of the first side wall 53. In other words, the first support portion 58 and the second support portion 57 are spaced apart from each other in the front-to-rear direction.

[0062] As shown in Figure 5, both support pillars 58a have mating holes 58b that fit with both ends of the oscillating shaft 42 in the first position, and both support pillars 57a have mating holes 57b that fit with both ends of the oscillating shaft 42 in the second position.

[0063] The shape of the sensor holder 5 is asymmetric with respect to a plane S2 that is perpendicular to the direction in which the first support portion 58 and the second support portion 57 are spaced apart (the front-rear direction in this embodiment) and that includes the center line 51a of the mounting surface 51. In this embodiment, the first support portion 58 and the second support portion 57 have different heights in the direction along the center line 51a from the mounting surface 51. The height of the first support portion 58 is smaller than the height of the second support portion 57.

[0064] As described above, in the seat belt retractor 1 of this embodiment, the sensor mounting angle differs between when the sensor holder 5 is in the first position and when it is in the second position, so the sensor mounting angle that can be adjusted with one sensor holder 5 can be increased compared to conventional cases. Therefore, when the sensor mounting angle is adjustable within a predetermined angle range (for example, a range of ±30 degrees), the number of sensor holders that need to be prepared can be reduced.

[0065] For example, if a sensor holder with a sensor mounting angle of -3 degrees at the reference angle position that can be replaced with sensor holder 5 is prepared, the sensor mounting angle can be adjusted to -21 degrees, -3 degrees, or 15 degrees in the first position, and the sensor mounting angle can be adjusted to 3 degrees, 21 degrees, or -15 degrees in the second position.

[0066] In addition, in this embodiment, the orientation of the sensor holder 5 relative to the mounting member 8 is reversed, so it is possible to select whether the sensor holder 5 is in the first position or the second position depending on the orientation of the sensor holder 5 when it is connected to the mounting member 8.

[0067] Furthermore, in this embodiment, since each of the first outward engagement portion 61 and the second outward engagement portion 63 is asymmetric with respect to the plane S1 including the rotation axis 50 and the center line 51a of the mounting surface 51, the mounting member 8 can be made to have a simple shape that is parallel to the side plate 21 of the housing 2 and symmetric with respect to the plane including the rotation axis 50.

[0068] Furthermore, in this embodiment, the sensor holder 5 includes a first support portion 58 that supports the sensor lever (7A, 7B or 7C) in the first position and a second support portion 57 that supports the sensor lever (sensor lever 7C in the reference angle position) in the second position, so that the sensor lever can be designed to face the same direction in both the first and second positions.

[0069] Furthermore, in this embodiment, the shape of the sensor holder 5 is asymmetric with respect to the plane S2 between the first support portion 58 and the second support portion 57, so that simply by looking at the sensor holder 5, it is possible to determine whether the sensor holder 5 is in the first posture or the second posture.

[0070] Moreover, since the first support portion 58 and the second support portion 57 are different in height, it is easy to determine whether the sensor holder 5 is in the first position or the second position.

[0071] (Variation) The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention.

[0072] For example, in the above embodiment, the mounting member 8 is attached to the side plate 21 of the housing 2 via the mechanism cover 11, but the mounting member 8 may be attached directly to the side plate 21. Also, the mounting member 8 may be provided integrally with the mechanism cover 11.

[0073] The sensor holder 5 does not necessarily have to include the two support portions 57, 58, but may include one support portion that supports the sensor lever so that it can swing in either the first position or the second position.

[0074] In addition, the shaft portions 55, 56 and the gripping portions 84, 85 may be omitted, and after the outward engaging portions 61, 63 of the sensor holder 5 are engaged with the inward engaging portions 86, 88 of the mounting member 8 in the first or second position, the inward engaging portions 86, 88 and the outward engaging portions 61, 63 may be bonded or welded together.

[0075] In addition, by ensuring that the angle difference between adjacent angular positions does not exceed the range in which the same sensor lever can be used, it may be possible to eliminate the need to rearrange the sensor lever when adjusting the sensor mounting angle in each of the first and second positions.

[0076] Furthermore, a vehicle acceleration sensor 4A of a first modified example shown in Figures 15(a) and 15(b) may be adopted, a vehicle acceleration sensor 4B of a second modified example shown in Figures 16(a) and 16(b) may be adopted, or a vehicle acceleration sensor 4C of a third modified example shown in Figures 17(a) and 17(b) may be adopted.

[0077] The vehicle acceleration sensor 4A of the first modified example shown in Figures 15(a) and 15(b) includes a mounting member 8A that is configured similarly to the mounting member 8 of the above embodiment except for including one inward engaging portion 91, and also includes a sensor holder 5A that is configured similarly to the sensor holder 5 of the above embodiment except for the first outward engaging portion 61 and the second outward engaging portion 63.

[0078] In the vehicle acceleration sensor 4A, as in the above embodiment, the orientation of the sensor holder 5A when it is connected to the mounting member 8A is reversed, so that it assumes either the first position shown in Figure 15(a) or the second position shown in Figure 15(b).

[0079] Similar to the inward engaging portions 86 and 88 of the above embodiment, the inward engaging portion 91 includes at least one inward protrusion 92 that points radially inward about the rotation axis 50. In the first modified example, the inward engaging portion 91 is provided on the second end portion 83 of the mounting member 8, the first outward engaging portion 61 is provided on the second side wall 54 of the sensor holder 5A, and the second outward engaging portion 63 is provided on the first side wall 53 of the sensor holder 5A. Therefore, the first outward engaging portion 61 engages with the inward engaging portion 91 in the first position, and the second outward engaging portion 63 engages with the inward engaging portion 91 in the second position.

[0080] However, the inward engaging portion 91 may be provided on the first end 82 of the mounting member 8, the first outward engaging portion 61 may be provided on the first side wall 53 of the sensor holder 5A, and the second outward engaging portion 63 may be provided on the second side wall 54 of the sensor holder 5A.

[0081] As in the above embodiment, the number of inward protrusions 92 and the number of outward protrusions 62, 64 may be multiple. Alternatively, the number of inward protrusions 92 may be multiple and the number of outward protrusions 62, 64 may be one. Conversely, the number of outward protrusions 62, 64 may be multiple and the number of inward protrusions 92 may be one. Also, in the first modified example, as in the above embodiment, the first outward engagement portion 61 and the second outward engagement portion 63 may each be asymmetric with respect to the plane S1 that includes the rotation axis 50 and the center line 51a of the mounting surface 51.

[0082] 10(a) and 10(b), in the above-described embodiment, the positions of the outward protrusions 62, 64 are the same between the first outward engagement portion 61 and the second outward engagement portion 63 when viewed in the extension direction of the rotation shaft 50. In the present embodiment, the positions of the outward protrusions 62, 64 in the circumferential direction around the rotation shaft 50 are different between the first outward engagement portion 61 and the second outward engagement portion 63 when viewed in the extension direction of the rotation shaft 50. Therefore, the multiple sensor mounting angles corresponding to the multiple angular positions when the sensor holder 5A is coupled to the mounting member 8A are different between the first posture and the second posture.

[0083] As in the above embodiment, the first modified example also makes it possible to adjust a larger number of sensor mounting angles with one sensor holder 5A than in the past. Moreover, in the first modified example, multiple sensor mounting angles can be easily set by varying the positions of the outward protrusions 62 of the first outward engagement portions 61 and the outward protrusions 64 of the second outward engagement portions 63.

[0084] The vehicle acceleration sensor 4B of the second modified example shown in Figures 16(a) and 16(b) includes a sensor holder 5B configured similarly to the sensor holder 5 of the above embodiment except for including one outward engaging portion 65, and also includes a mounting member 8B configured similarly to the mounting member 8 of the above embodiment except for the first inward engaging portion 86 and the second inward engaging portion 88.

[0085] In the vehicle acceleration sensor 4B, as in the above embodiment, the orientation of the sensor holder 5B when connected to the mounting member 8B is reversed, so that the sensor assumes either the first position shown in Figure 16(a) or the second position shown in Figure 16(b).

[0086] Similar to the outward engagement portions 61 and 63 of the above embodiment, the outward engagement portion 65 includes at least one outward protrusion 66 that points outward in the radial direction centered on the rotation axis 50. In the second modified example, the outward engagement portion 65 is provided on the second side wall 54 of the sensor holder 5B, the first inward engagement portion 86 is provided on the second end portion 83 of the mounting member 8B, and the second inward engagement portion 88 is provided on the first end portion 82 of the mounting member 8B. Therefore, the first inward engagement portion 86 engages with the outward engagement portion 65 in the first position, and the second inward engagement portion 88 engages with the outward engagement portion 65 in the second position.

[0087] However, the outward engaging portion 65 may be provided on the first side wall 53 of the sensor holder 5B, the first inward engaging portion 86 may be provided on the first end 82 of the mounting member 8B, and the second inward engaging portion 88 may be provided on the second end 83 of the mounting member 8B.

[0088] As in the above embodiment, the number of outward protrusions 66 and the number of inward protrusions 87, 89 may be multiple. Alternatively, the number of outward protrusions 66 may be multiple and the number of inward protrusions 87, 89 may be one. Conversely, the number of inward protrusions 87, 89 may be multiple and the number of outward protrusions 66 may be one. Also, in the second modified example, as in the above embodiment, the outward engagement portion 65 may be asymmetric with respect to the plane S1 that includes the rotation shaft 50 and the center line 51a of the mounting surface 51.

[0089] 10(a) and 10(b), in the above-described embodiment, the positions of the inward protrusions 87, 89 were the same between the first inward engagement portion 86 and the second inward engagement portion 88 when viewed in the direction in which the rotation shaft 50 extends. In the present embodiment, the positions of the inward protrusions 87, 89 in the circumferential direction around the rotation shaft 50 are different between the first inward engagement portion 86 and the second inward engagement portion 88 when viewed in the direction in which the rotation shaft 50 extends. Therefore, the multiple sensor mounting angles corresponding to the multiple angular positions when the sensor holder 5B is coupled to the mounting member 8B are different between the first posture and the second posture.

[0090] In the second modified example, as in the above embodiment, the number of sensor mounting angles that can be adjusted with one sensor holder 5B can be increased compared to the conventional example. Moreover, in this embodiment, multiple sensor mounting angles can be easily set by changing the positions of the inward protrusions 87 of the first inward engagement portions 86 and the inward protrusions 89 of the second inward engagement portions 88.

[0091] In addition, in the second variant, the tip of the first support portion 58 is slanted, while the tip of the second support portion 57 is flat, so that the shape of the sensor holder 5B is asymmetric with respect to a plane S2 that is perpendicular to the direction of separation between the first support portion 58 and the second support portion 57 and includes the center line 51a of the mounting surface 51.

[0092] The vehicle acceleration sensor 4C of the third modified example shown in Figures 17(a) and 17(b) includes a mounting member 8C configured in the same manner as the mounting member 8 of the above embodiment except for the first inward engagement portion 93 and the second inward engagement portion 95, and also includes a sensor holder 5C configured in the same manner as the sensor holder 5 of the above embodiment except for the first outward engagement portion 6A and the second outward engagement portion 6C.

[0093] In the vehicle acceleration sensor 4C, as in the above embodiment, the orientation of the sensor holder 5C when connected to the mounting member 8C is reversed, so that the sensor assumes either the first position shown in Figure 17(a) or the second position shown in Figure 17(b).

[0094] Similar to the inward engagement portions 86, 88 of the above-described embodiment, the first inward engagement portion 93 and the second inward engagement portion 95 each include at least one inward protrusion 94, 96 that points radially inward around the rotation shaft 50. In this embodiment, the first inward engagement portion 93 is positioned outward from the second inward engagement portion 95 in the radial direction around the rotation shaft 50.

[0095] Similar to the outward engagement portions 61, 63 of the above-described embodiment, the first outward engagement portion 6A and the second outward engagement portion 6C each include at least one outward protrusion 6B, 6D that points outward in the radial direction centered on the rotation shaft 50. In this embodiment, the first outward engagement portion 6A is positioned more outer than the second outward engagement portion 6C in the radial direction centered on the rotation shaft 50.

[0096] In the third variant, the first outward engagement portion 6A and the second outward engagement portion 6C are provided on the second side wall 54 of the sensor holder 5C, the first inward engagement portion 93 is provided on the second end 83 of the mounting member 8C, and the second inward engagement portion 95 is provided on the first end 82 of the mounting member 8C.

[0097] The first outward engagement portion 6A engages with the first inward engagement portion 93 but does not engage with the second inward engagement portion 95 in the first position, and does not engage with the first inward engagement portion 93 or the second inward engagement portion 95 in the second position. The second outward engagement portion 6C does not engage with the first inward engagement portion 93 or the second inward engagement portion 95 in the first position, and engages with the second inward engagement portion 95 but does not engage with the first inward engagement portion 93 in the second position.

[0098] 17(a) and 17(b), the positions at which the first outward engagement portion 6A and the second outward engagement portion 6C and the first inward engagement portion 93 and the second inward engagement portion 95 are provided may be changed as appropriate. Also, in the third modified example, as in the above embodiment, the first outward engagement portion 6A and the second outward engagement portion 6C may each be asymmetric with respect to the plane S1 that includes the rotation axis 50 and the center line 51a of the mounting surface 51.

[0099] As in the above embodiment, there may be a plurality of outward protrusions 6B, 6D and a plurality of inward protrusions 94, 96. Alternatively, there may be a plurality of outward protrusions 6B, 6D and a single inward protrusion 94, 96. Conversely, there may be a plurality of inward protrusions 94, 96 and a single outward protrusion 6B, 6D.

[0100] In the third modified example, as in the previous embodiment, the multiple sensor mounting angles corresponding to the multiple angular positions when the sensor holder 5C is coupled to the mounting member 8C differ between the first and second postures. This allows a greater number of sensor mounting angles to be adjusted with a single sensor holder 5C than in the past. Furthermore, in this embodiment, the first engagement structure between the first inward engagement portion 93 and the first outward engagement portion 6A and the second engagement structure between the second inward engagement portion 95 and the second outward engagement portion 6C can be made different. For example, the size and pitch of the outward protrusions and inward protrusions can be made different between the first engagement structure and the second engagement structure.

[0101] In addition, in the third variant, the width of the tip of the first support portion 58 is narrower than the thickness of the second side wall 54, while the width of the second support portion 57 is equal to the thickness of the first side wall 53 up to the tip, so that the shape of the sensor holder 5C is asymmetric with respect to a plane S2 that is perpendicular to the separation direction between the first support portion 58 and the second support portion 57 and includes the center line 51a of the mounting surface 51.

[0102] In the above embodiment, the orientation of the sensor holder 5 when coupled to the mounting member 8 was reversible. However, the orientation of the sensor holder 5 when coupled to the mounting member 8 may not be reversible, and the orientation of the mounting member 8 relative to the housing 2 may be reversed so that the sensor holder 5 can be attached to the housing 2 in either the first position or the second position. With this configuration, it is possible to select whether the sensor holder is in the first position or the second position depending on the orientation of the mounting member 8 when attached to the housing 2. Even in this case, for example, if the first outward engaging portion 61 and the second outward engaging portion 63 are asymmetric with respect to the plane S1 that includes the rotation axis 50 and the center line 51a of the mounting surface 51, or if the first inward engaging portion 86 and the second inward engaging portion 88 are asymmetric with respect to the plane that is parallel to the side plate 21 of the housing 2 and includes the rotation axis 50, the sensor mounting angles will be different between the first position and the second position.

[0103] To prevent the orientation of the sensor holder 5 from being reversed when coupled to the mounting member 8, for example, the first shaft portion 55 and the second shaft portion 56 may have different diameters. Also, if the orientation of the mounting member 8 when attached to the housing 2 is reversible, the mounting member 8 may include only one inward engaging portion, and the sensor holder 5 may include only one outward engaging portion.

[0104] In the above embodiment, the orientation of the sensor holder 5 is adjusted along a plane parallel to the back plate 23 of the housing 2, but when the seat belt retractor 1 is tilted while the axial direction of the take-up drum 3 is kept horizontal, the inclination of the sensor holder 5, that is, the inclination of the center line 51a of the mounting surface 51 relative to the back plate 23 of the housing 2, may be adjusted along a plane (here, the side plate 21) perpendicular to the axial direction of the take-up drum 3. That is, as in a vehicle acceleration sensor 4D of a fourth modified example shown in Fig. 18 (Fig. 18 is a view of the vehicle acceleration sensor 4D in the first attitude as seen from behind), the rotation axis 50 of the sensor holder 5D may extend in the left-right direction.

[0105] In this case, the first side wall 53 and the second side wall 54 of the sensor holder 5D are located on both sides of the support portion 52 in the left-right direction, and the first end 82 and the second end 83 of the mounting member 8D are located on both sides of the base 81 in the left-right direction. Furthermore, a pair of support posts 58a of the first support portion 58, which swingably supports a sensor lever (not shown) in the first position, are provided at the rear ends of both the first side wall 53 and the second side wall 54. A pair of support posts 57a of the second support portion 57, which swingably supports a sensor lever (not shown) in the second position (which may be the same as or different from the sensor lever used in the first position, as in the previous embodiment), are provided at the front ends of both the first side wall 53 and the second side wall 54. Therefore, the fitting holes 57b, 58b provided in the support posts 57a, 58a are parallel to the rotation axis 50. That is, the oscillation shaft 42 is attached to the sensor holder 5D with its longitudinal direction parallel to the rotation axis 50.

[0106] In the fourth modified example, the orientation of the sensor holder 5D when coupled to the mounting member 8D is reversed, so that the sensor holder 5D is in either the first or second position. As in the above embodiment, the sensor mounting angles differ between the first and second positions of the sensor holder 5D, so that a single sensor holder 5D can accommodate a greater number of sensor mounting angles than before.

[0107] Furthermore, in the sensor holder 5D of the fourth modified example, as in the sensor holder 5 of the above embodiment, the height of the first support part 58 is smaller than the height of the second support part 57 in the direction along the center line 51a from the mounting surface 51 (only the tips of the pair of pillars 57a of the second support part 57 are visible in Figure 18), so that the shape of the sensor holder 5D is asymmetric with respect to a plane S2 that is perpendicular to the direction separating the first support part 58 and the second support part 57 (in this embodiment, the front-to-back direction) and includes the center line 51a of the mounting surface 51. [Explanation of symbols]

[0108] 1 Seat belt retractor 2. Housing 3 Winding drum 4, 4A~4D Vehicle acceleration sensor 41 Inertial mass body 5,5A~5D Sensor holder 50 Rotational Axis 51 Placement surface 51a center line 57 Second support part 58 1st support part 61 first outward engaging portion 62 Outward protrusion 63 Second outward engaging portion 64 outward projection 65 Outward engagement part 66 Outward protrusion 6A First outward engaging portion 6B Outward protrusion 6C Second outward engaging portion 6D Outward protrusion 7A~7C Sensor lever 8, 8A to 8D Mounting parts 86 First inward engaging portion 87 Inward protrusion 88 Second inward engaging portion 89 Inward projection 91 Inward engagement portion 92 Inward protrusion 93 First inward engaging portion 94 Inward protrusion 95 Second inward engaging portion 96 Inward protrusion

Claims

1. a vehicle acceleration sensor that is in a detection state when the acceleration of the vehicle reaches or exceeds a predetermined value; a take-up drum that is accommodated in a housing so as to be rotatable in a webbing unwinding direction and a webbing winding direction, and that is prevented from rotating in the webbing unwinding direction when the vehicle acceleration sensor is in a detection state; The vehicle acceleration sensor a spherical inertial mass; a sensor holder having a mounting surface on which the inertial mass body is placed, the mounting surface having a cone-shaped cross section symmetrical with respect to a center line of the mounting surface; a sensor lever supported by the sensor holder so as to be swingable, the sensor lever being pushed up by the inertial mass body rolling on the mounting surface when the acceleration of the vehicle reaches or exceeds the predetermined value; a mounting member to which the sensor holder is coupled and which is attached to the housing; the mounting member is attached to the housing in a state in which the sensor holder is in one of a first posture and a second posture inverted around a center line of the mounting surface relative to the first posture, the sensor holder can be coupled to the mounting member at any one of a plurality of angular positions, which are positions rotated around a rotation axis extending in a direction perpendicular to a center line of the mounting surface, in each of the first posture and the second posture; A seat belt retractor characterized in that, between the first posture and the second posture, multiple sensor mounting angles, which are angles of the center line of the mounting surface relative to the housing corresponding to the multiple angular positions, are different.

2. the sensor holder is provided with an outward engaging portion including at least one outward protrusion that points outward in a radial direction about the rotation axis; The mounting member is provided with an inward engaging portion that is engageable with the outward engaging portion and that includes at least one inward protrusion that points inward in a radial direction about the rotation axis, a plurality of the at least one outward protrusion and / or the at least one inward protrusion are provided and aligned in a circumferential direction around the rotation axis, 2. The seat belt retractor according to claim 1, wherein the sensor holder is coupled to the mounting member at any one of the plurality of angular positions by changing the engagement state between the outward engagement portion and the inward engagement portion.

3. 3. The seat belt retractor according to claim 2, wherein the sensor holder is in either the first position or the second position by reversing the orientation when coupled to the mounting member, and the outward engaging portion and the inward engaging portion are engaged in both the first position and the second position.

4. the inward engaging portion is one, the outward engaging portion includes a first outward engaging portion that engages with the inward engaging portion in the first orientation and a second outward engaging portion that engages with the inward engaging portion in the second orientation, 4. The seat belt retractor according to claim 3, wherein the first outward engagement portion and the second outward engagement portion have different positions of the at least one outward protrusion when viewed from the extending direction of the rotation shaft.

5. the outward engaging portion is one, the inward engaging portion includes a first inward engaging portion that engages with the outward engaging portion in the first orientation and a second inward engaging portion that engages with the outward engaging portion in the second orientation; 4. The seat belt retractor according to claim 3, wherein the first inward engagement portion and the second inward engagement portion have different positions of the at least one inward protrusion when viewed from the extending direction of the rotation shaft.

6. the inward engaging portion includes a first inward engaging portion and a second inward engaging portion, 4. The seat belt retractor according to claim 3, wherein the outward engagement portion includes a first outward engagement portion that engages with the first inward engagement portion but does not engage with the second inward engagement portion in the first position, and does not engage with the first inward engagement portion and the second inward engagement portion in the second position, and a second outward engagement portion that does not engage with the first inward engagement portion and the second inward engagement portion in the first position, and engages with the second inward engagement portion but does not engage with the first inward engagement portion in the second position.

7. 3. The seat belt retractor according to claim 2, wherein the mounting member can be attached to the housing in either a state in which the sensor holder is in the first position or a state in which the sensor holder is in the second position by reversing its orientation relative to the housing.

8. 8. The seat belt retractor according to claim 2, wherein the outward engaging portion is asymmetric with respect to a plane including the rotation axis and a center line of the mounting surface.

9. 9. The seat belt retractor according to claim 1, wherein the sensor holder has a first support portion that supports the sensor lever so that it can swing in the first position, and a second support portion that is located on the opposite side of the center line of the mounting surface from the first support portion and that supports the sensor lever so that it can swing in the second position.

10. 10. The seat belt retractor according to claim 9, wherein the shape of the sensor holder is asymmetric with respect to a plane that is perpendicular to a direction separating the first support portion and the second support portion and that includes a center line of the mounting surface.

11. 11. The seat belt retractor according to claim 10, wherein the first support portion and the second support portion of the sensor holder are different in height from the mounting surface in the direction along the center line.

Images