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 mounted on a vehicle and configured to pull out and wind up a webbing serving as a seat belt.

Background Art

[0002] Conventionally, there has been known a seat belt retractor including a vehicle acceleration sensor that becomes a detection state when the acceleration of a vehicle reaches a predetermined value or more, and that prevents the pulling out of a webbing 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 winding drum 120 rotatably accommodated between the side plates of the housing 110 in the webbing pulling-out direction and the winding direction, and a vehicle acceleration sensor 130 attached to one side plate of the housing 110.

[0004] The vehicle acceleration sensor 130 includes a spherical inertial mass 140, a sensor holder 150 having a mounting surface 151 on which the inertial mass 140 is placed, and a sensor lever 160 swingably supported by the sensor holder 150. When the acceleration of the vehicle reaches a predetermined value or more, the sensor lever 160 is pushed up by the inertial mass 140 rolling on the mounting surface 151. Thereby, the rotation of the winding drum 120 in the webbing pulling-out direction is prevented.

[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 where it is tilted in the longitudinal and / or widthwise directions 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 brought closer to horizontal even when the axial direction of the winding drum 120 is tilted with respect to the horizontal plane. That is, the tilt of the sensor holder 150 is adjusted along a plane parallel to the back plate of the housing 110.

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

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

[0009] [Patent Document 1] China Utility Model Publication No. 201856732 Specification [Patent Document 2] Patent No. 5515180 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] However, in the seat belt retractor 100 of Patent Document 1, where the engaging portions 171 and 153 have multiple engaging teeth, 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 engaging teeth. Therefore, if it is desired to adjust the sensor mounting angle to an angle between the pitches of the engaging teeth, it is necessary to prepare a separate sensor holder 150 with a shifted pitch of the engaging teeth.

[0011] Therefore, the present invention aims to provide a seat belt retractor that allows for a greater range of adjustable sensor mounting angles with a single sensor holder than conventional models. [Means for solving the problem]

[0012] To solve the above problems, the present invention provides a vehicle acceleration sensor that enters a detection state when the acceleration of a vehicle exceeds a predetermined value, and a winding drum that is rotatably housed in a housing in the webbing's pulling-out and winding directions, and which prevents the webbing from rotating in the pulling-out direction when the vehicle acceleration sensor enters a detection state, wherein the vehicle acceleration sensor comprises a spherical inertial mass, a sensor holder having a mortar-shaped mounting surface on which the inertial mass is placed and having a cross-sectional shape symmetrical with respect to its center line, and a sensor lever that is swingably supported by the sensor holder, which is pushed up by the inertial mass rolling on the aforementioned mounting surface when the acceleration of the vehicle exceeds the predetermined value The seat belt retractor is characterized in that it includes a mounting member to which the sensor holder is coupled and which is attached to the housing, wherein the mounting member is attached to the housing in a state in which the sensor holder is in either a first position or a second position which is inverted around the center line of the mounting surface described above relative to the first position, the sensor holder can be coupled to the mounting member at any of a plurality of angular positions which are positions rotated around a rotation axis which extends in a direction perpendicular to the center line of the mounting surface described above in each of the first and second positions, and the plurality of sensor mounting angles which are the angles of the center line of the mounting surface described above relative to the housing, corresponding to the plurality of angular positions, are different in the first and second positions.

[0013] With the above configuration, the sensor mounting angle differs between the first and second positions of the sensor holder, allowing for a greater range of adjustable sensor mounting angles with a single sensor holder compared to conventional designs. Therefore, the number of sensor holders required can be reduced when adjusting the sensor mounting angle within a predetermined range.

[0014] For example, the sensor holder is provided with an outward-facing engagement portion including at least one outward-facing projection that points radially outward with respect to the axis of rotation, and the mounting member is provided with an inward-facing engagement portion that is engageable with the outward-facing engagement portion and includes at least one inward-facing projection that points radially inward with respect to the axis of rotation, and one or both of the at least one outward-facing projection and the at least one inward-facing projection are provided in a plurality of arrangements in the circumferential direction with respect to the axis of rotation, and the sensor holder may be coupled to the mounting member at any of the plurality of angular positions by changing the engagement state between the outward-facing engagement portion and the inward-facing engagement portion.

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

[0016] The inward engaging portion is one, and the outward engaging portion includes 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, wherein the positions of the at least one outward projection may differ between the first outward engaging portion and the second outward engaging portion when viewed from the extending direction of the rotation axis. With this configuration, multiple sensor mounting angles can be easily set by the difference in position between the outward projection of the first outward engaging portion and the outward projection of the second outward engaging portion.

[0017] The outward-facing engaging portion is one, and the inward-facing engaging portion includes a first inward-facing engaging portion that engages with the outward-facing engaging portion in the first position and a second inward-facing engaging portion that engages with the outward-facing engaging portion in the second position, wherein the positions of the at least one inward-facing projection may differ between the first inward-facing engaging portion and the second inward-facing engaging portion when viewed from the extending direction of the rotation axis. With this configuration, multiple sensor mounting angles can be easily set by the difference in position between the inward-facing projection of the first inward-facing engaging portion and the inward-facing projection of the second inward-facing engaging portion.

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

[0019] The mounting member may be reversible in orientation relative to the housing so that the sensor holder can be attached to the housing in either the first position or the second position. With this configuration, the orientation of the mounting member when attaching to the housing can be used to select whether the sensor holder is in the first or second position.

[0020] The outward-facing engaging portion may be asymmetrical with respect to the plane containing the rotation axis and the center line of the mounting surface described above. This configuration allows the mounting member to have a symmetrical and simple shape.

[0021] The sensor holder may have a first support portion that supports the sensor lever so as to be swingable in the first posture, and a second support portion that is located on the opposite side of the first support portion with respect to the center line of the placement surface and supports the sensor lever so as to be swingable in the second posture. According to this configuration, the sensor lever can be designed in the same direction in the first posture and the second posture.

[0022] The shape of the sensor holder may be asymmetric with respect to a plane that is perpendicular to the separation direction between the first support portion and the second support portion and includes the center line of the placement surface. According to this configuration, it is possible to determine whether the sensor holder is in the first posture or the second posture just by looking at the sensor holder.

[0023] The heights of the first support portion and the second support portion of the sensor holder in the direction along the center line from the placement surface may be different. According to this configuration, it is possible to easily determine whether the sensor holder is in the first posture or the second posture.

Advantages of the Invention

[0024] According to the present invention, it is possible to increase the number of sensor mounting angles that can be adjusted with one sensor holder as compared with the conventional art.

Brief Description of the Drawings

[0025] [Figure 1] It is a perspective view of a seat belt retractor according to an embodiment of the present invention. [Figure 2] It is an exploded perspective view of the seat belt retractor shown in FIG. 1 as viewed from one side surface. [Figure 3] It is an exploded perspective view of the seat belt retractor shown in FIG. 1 as viewed from the other side surface. [Figure 4] It is a perspective view of a vehicle acceleration sensor in a state where a sensor holder is coupled to a mounting member at a reference angular position. [Figure 5] It is an exploded perspective view of the vehicle acceleration sensor shown in FIG. 4. [Figure 6] It is a perspective view of a sensor holder. [Figure 7] This is a perspective view of the mounting component. [Figure 8] This is a cross-sectional view along line VIII-VIII in Figure 4. [Figure 9] This is a cross-sectional view along the line IX-IX in Figure 8. [Figure 10] (a) and (b) are cross-sectional views along the XA-XA and XB-XB lines in Figure 9, respectively. [Figure 11] (a) is a perspective view of the vehicle acceleration sensor with the sensor holder 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 engaging portion and the outward engaging portion at that time. [Figure 12] (a) is a perspective view of the vehicle acceleration sensor with the sensor holder connected to the mounting member at an angle adjacent to the reference angle position (opposite to Figure 11(a)), and (b) is a cross-sectional view showing the engagement state of the inward engaging portion and the outward engaging portion at that time. [Figure 13] (a) is a perspective view of a vehicle acceleration sensor with the sensor holder, whose orientation relative to the mounting member is reversed, connected to the mounting member at a reference angular position, and (b) is a cross-sectional view showing the engagement state of the inward-facing engagement portion and the outward-facing engagement portion at that time. [Figure 14] (a) and (b) are schematic diagrams showing the state of the sensor holder in the vehicle acceleration sensor used in the above embodiment before and after inversion. [Figure 15] (a) and (b) are schematic diagrams showing the state of the vehicle acceleration sensor before and after inversion. [Figure 16] (a) and (b) are schematic diagrams showing the state of the vehicle acceleration sensor before and after inversion. [Figure 17] (a) and (b) are schematic diagrams showing the state of the vehicle acceleration sensor before and after inversion. [Figure 18] This diagram schematically shows the sensor holder in the vehicle acceleration sensor of the fourth modified example. [Figure 19]This is a perspective view of a conventional seat belt retractor. [Modes for carrying out the invention]

[0026] Figures 1-3 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 extends and retracts the webbing used 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 rotatably housed between the side plates 21, 22 of the housing 2 in the direction of webbing extension and winding, and a vehicle acceleration sensor 4 attached to the side plate 21 of the housing 2.

[0028] The side plates 21 and 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 the sake 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 with the side plates 21 and 22 is the front, and the opposite side is the rear). Also, as drawn in Figure 1, one of the directions perpendicular to the left-right direction and the front-rear direction will be referred to as upward, and the other as downward.

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

[0030] A mechanism cover 11 is attached to the side plate 21 of the housing 2, and a winding spring unit 15 (omitted in Figures 2 and 3) is attached to the side plate 22 of the housing 2. The mechanism cover 11 and the winding spring unit 15 rotatably support the winding drum 3. Since the configuration of the winding spring unit 15 is publicly known, a detailed explanation is omitted.

[0031] The winding drum 3 has a roughly cylindrical drum body 31 and roughly disc-shaped ends 32 and 33 that are larger in diameter than the drum body 31. End 32 is the part that fits into the opening 21a of the side plate 21 of the housing 2, and end 33 is the part that fits into the opening 22a of the side plate 22 of the housing 2.

[0032] Internal teeth 21b are formed around the periphery of the opening 21a in the side plate 21 of the housing 2. Meanwhile, although not shown in the figures, a pawl capable of engaging with the internal teeth 21b is held inside the end portion 32 of the winding drum 3. A clutch 35 for operating the pawl is also attached to the end portion 32.

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

[0034] The side plate 21 of the housing 2 is also provided with an opening 21c below the opening 21a to avoid interference with the vehicle acceleration sensor 4 (more precisely, the sensor cover 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 has a first housing chamber 12 for housing the clutch 35 and a second housing chamber 13 for housing most of the vehicle acceleration sensor 4. Furthermore, a sensor cover 14 is attached to the mechanism cover 11 via a hinge. The sensor cover 14 is placed over the vehicle acceleration sensor 4 after it has been inserted into the second housing chamber 13.

[0036] The vehicle acceleration sensor 4 enters a detection state when the vehicle's acceleration exceeds a predetermined value. When the vehicle acceleration sensor 4 enters a detection state, the engaging claw 74 of the sensor lever 7A (or 7B or 7C), described later, engages with the external teeth of the clutch 35. This prevents the clutch 35 from rotating in the direction of webbing withdrawal, and the winding drum 3 rotates relative to the clutch 35. This relative rotation causes the pawl to pop out from the end 32 of the winding drum 3 and engage with the internal teeth 21b, preventing the winding drum 3 from rotating in the direction of webbing withdrawal.

[0037] However, the structure for preventing the winding drum 3 from rotating in the direction of webbing withdrawal is not limited to this embodiment and can be modified as appropriate. For example, although not shown in the figures, a pawl may be pivotably attached to the side plate 21 of the housing 2 instead of the end 32 of the winding drum 3, and a gear that can engage with the pawl may be attached to the winding 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 pivotably supported by the sensor holder 5. When the vehicle acceleration sensor 4 detects an acceleration, the sensor lever 7A is pushed up by the inertial mass 41 rolling on the mounting surface 51. Furthermore, the vehicle acceleration sensor 4 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] As shown in Figures 8 and 9, the mounting surface 51 of the sensor holder 5 is shaped like a mortar, with a cross-sectional shape symmetrical with respect to the center line 51a of the mounting surface 51. The cross-sectional shape of the mounting surface 51 may be straight or curved. Furthermore, the cross-sectional shape of the mounting surface 51 may be the same in all directions (i.e., spherically symmetric), or it may be different in the front-to-back direction and the left-to-right direction.

[0040] In this embodiment, the vehicle acceleration sensor 4 is configured to accommodate a state in which the axial direction of the winding drum 3 is tilted with respect to the horizontal plane. That is, the tilt of the sensor holder 5 (the tilt 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 such that the sensor holder 5 is 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 the first position reversed around the center line 51a of the mounting surface 51. In this embodiment, the sensor holder 5 is in either the first or second position by reversing its orientation when it is 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 constitutes a 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-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 vertical direction and facing the support portion 52 of the sensor holder 5, and a first end portion 82 and a second end portion 83 located on both sides of the base 81 in the front-rear direction, extending upward from the base 81.

[0044] The sensor holder 5 can be attached to the mounting member 8 at any of several angular positions, which are positions rotated around a rotation axis 50 extending in the front-rear direction in both the first and second orientations. 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, so the front-rear direction is also perpendicular to the center line 51a of the mounting surface 51.

[0045] In this embodiment, as shown in Figures 9, 10(a) and 10(b), the sensor holder 5 is provided with a first outward engaging portion 61 and a second outward engaging portion 63, and the mounting member 8 is provided with a first inward engaging portion 86 and a second inward engaging portion 88. The first inward engaging portion 86 and the second inward engaging portion 88 can engage with the first outward engaging portion 61 and the second outward engaging portion 63. The first outward engaging portion 61 is provided on the first side wall 53 of the sensor holder 5, and the second outward engaging portion 63 is provided on the second side wall 54 of the sensor holder 5. The first inward engaging portion 86 is provided on the first end portion 82 of the mounting member 8, and the second inward engaging portion 88 is provided on the second end portion 83 of the mounting member 8.

[0046] Figures 14(a) and 14(b) schematically show the state of the sensor holder before and after inversion. As shown in Figure 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 Figure 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] The first side wall 53 and the second side wall 54 of the sensor holder 5 are provided with shaft portions 55 and 56 centered on the rotation axis 50, respectively, and the first end 82 and the second end 83 of the mounting member 8 are provided with gripping portions 84 and 85, respectively. The shaft portions 55 and 56 protrude from the first side wall 53 and the second side wall 54 in opposite directions. The state in which the sensor holder 5 is coupled to the mounting member 8 (the state in which the outward engaging portions 61 and 63 and the inward engaging portions 86 and 88 are engaged) is maintained when the shaft portions 55 and 56 are gripped by the gripping portions 84 and 85.

[0048] The first outward engaging portion 61 includes at least one outward-facing projection 62 that points radially outward around the rotation axis 50, as shown in Figure 10(a). Similarly, the second outward engaging portion 63 includes at least one outward-facing projection 64 that points radially outward around the rotation axis 50, as shown in Figure 10(b). In this embodiment, a plurality of outward-facing projections 62 (seven in the illustrated example) are arranged in the circumferential direction around the rotation axis 50, and a plurality of outward-facing projections 64 (seven in the illustrated example) are arranged in the circumferential direction around the rotation axis 50.

[0049] On the other hand, the first inward engaging portion 86 includes at least one inward projection 87 that points radially inward around the rotation axis 50, as shown in Figure 10(a). Similarly, the second inward engaging portion 88 includes at least one inward projection 89 that points radially inward around the rotation axis 50, as shown in Figure 10(b). In this embodiment, a plurality of (six in the illustrated example) inward projections 87 are arranged in the circumferential direction around the rotation axis 50, and a plurality of (six in the illustrated example) inward projections 89 are arranged in the circumferential direction around the rotation axis 50.

[0050] In this embodiment, the pitch of the outward-facing protrusions 62, 64 and the pitch of the inward-facing protrusions 87, 89 are 18 degrees. However, the number of either the outward-facing protrusions 62, 64 or the inward-facing engaging portions 86, 88 may be one.

[0051] In the first position, the sensor holder 5 is connected to the mounting member 8 at one of several angular positions by changing the engagement state between the first outward engaging portion 61 and the first inward engaging portion 86, and the engagement state between the second outward engaging portion 63 and the second inward engaging portion 88. Similarly, in the second position, the sensor holder 5 is connected to the mounting member 8 at one of several angular positions by changing the engagement state between the first outward engaging portion 61 and the second inward engaging portion 88, and the engagement state between the second outward engaging portion 63 and the first inward engaging portion 86. In other words, the angular difference between adjacent angular positions is equal to the pitch of the outward projections 62 and 64 and the pitch of the inward projections 87 and 89.

[0052] As described above, in this embodiment, there are 7 outward-facing protrusions 62,64 and 6 inward-facing protrusions 87,89. Therefore, the number of angular positions in both the first and second postures is 3 in total: the reference angular position and the two adjacent positions. In the reference angular position in the first posture, as shown in Figures 10(a) and (b), the two outermost outward-facing protrusions 62,64 are located outside the inward-facing protrusions 87,89. In the angular position adjacent to the reference angular position in the first posture, as shown in Figures 11(b) and 12(b), the two outermost outward-facing protrusions 62,64 are located outside the inward-facing protrusions 87,89. The same applies to the reference angular position and the angular positions adjacent to the reference angular position in the second posture.

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

[0054] Furthermore, the asymmetry described above means that when the number of outward-facing protrusions 62,64 is odd, the vertices of the central outward-facing protrusions 62,64 are not located on the plane S1 that includes the rotation axis 50 and the center line 51a of the mounting surface 51, and when the number of outward-facing protrusions 62,64 is even, the bottom of the groove formed between the two central outward-facing protrusions 62,64 is not located on the plane S1 that includes 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, positive when the center line 51a of the mounting surface 51 tilts inward from the side plate 21, and negative when it tilts outward. In other words, 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 orientation, the sensor mounting angle is -12 degrees at the reference angular position shown in Figures 4, 10(a) and 11(b), -30 degrees at the adjacent angular position shown in Figures 11(a) and 11(b), and 6 degrees at the opposite adjacent angular position shown in Figures 12(a) and 12(b). On the other hand, in the second orientation, the reference angular position shown in Figures 13(a) and 13(b) is 12 degrees, and the adjacent and opposite adjacent angular positions are -6 degrees and 30 degrees, respectively.

[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 as shown in Figures 12(a) and 12(b), sensor lever 7C is used when the sensor mounting angle is 6 degrees. 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 in the illustration, 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 pivot portion 71 that passes through the oscillating shaft 42 (see Figure 5), an arm portion 72 extending in the front-rear direction from the pivot portion 71, a dish portion 73 provided at the tip of the arm portion 72 that is placed over the inertial mass body 41 on the side opposite to the mounting surface 51, and an engaging claw 74 protruding upward from the dish portion 73.

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

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

[0061] In this embodiment, the first support section 58 is composed of a pair of support columns 58a that protrude from both ends of the second side wall 54 parallel to the center line 51a of the mounting surface 51, and the second support section 57 is composed of a pair of support columns 57a that protrude from both ends of the first side wall 53 parallel to the center line 51a of the mounting surface 51. That is, the first support section 58 and the second support section 57 are spaced apart from each other in the front-rear direction.

[0062] As shown in Figure 5, both support columns 58a are provided with fitting holes 58b that engage with both ends of the oscillating shaft 42 in the first position, and both support columns 57a are provided with fitting holes 57b that engage with both ends of the oscillating shaft 42 in the second position.

[0063] The shape of the sensor holder 5 is perpendicular to the direction of separation between the first support portion 58 and the second support portion 57 (in this embodiment, the front-to-back direction) and asymmetric with respect to the plane S2 which includes the center line 51a of the mounting surface 51. In this embodiment, the height of the first support portion 58 and the second support portion 57 differs 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 the first and second positions of the sensor holder 5. Therefore, the number of sensor mounting angles that can be adjusted with a single sensor holder 5 can be increased compared to conventional designs. For this reason, when it is necessary to adjust the sensor mounting angle within a predetermined angle range (for example, within 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 a reference angle position is prepared that is replaceable with sensor holder 5, the sensor mounting angle can be adjusted to -21 degrees, -3 degrees, or 15 degrees in the first orientation, and the sensor mounting angle can be adjusted to 3 degrees, 21 degrees, or -15 degrees in the second orientation.

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

[0067] Furthermore, in this embodiment, since the first outward engaging portion 61 and the second outward engaging portion 63 are asymmetrical with respect to the plane S1 which includes the rotation axis 50 and the center line 51a of the mounting surface 51, the mounting member 8 can have a simple shape that is parallel to the side plate 21 of the housing 2 and symmetrical with respect to the plane which includes 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 at the reference angle position) in the second position, so the sensor lever can be designed to be oriented in the same direction in both the first and second positions.

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

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

[0071] (modified version) The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0072] For example, in the above embodiment, the mounting member 8 was 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. Alternatively, the mounting member 8 may be provided integrally with the mechanism cover 11.

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

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

[0075] Furthermore, 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 the first and second orientations, respectively.

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

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

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

[0079] The inward engaging portion 91, like the inward engaging portions 86 and 88 in the above embodiment, includes at least one inwardly pointed projection 92 that points radially inward with respect to 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, in the first position, the first outward engaging portion 61 engages with the inward engaging portion 91, and in the second position, the second outward engaging portion 63 engages with the inward engaging portion 91.

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

[0081] Similar to the above embodiment, the number of inward-facing protrusions 92 and outward-facing protrusions 62, 64 may be multiple. Alternatively, there may be multiple inward-facing protrusions 92 and one outward-facing protrusion 62, 64. Conversely, there may be multiple outward-facing protrusions 62, 64 and one inward-facing protrusion 92. Furthermore, in the first modified example, similar to the above embodiment, the first outward-facing engaging portion 61 and the second outward-facing engaging portion 63 may each be asymmetrical with respect to the plane S1 that includes the rotation axis 50 and the center line 51a of the mounting surface 51.

[0082] In the above embodiment, as shown in Figures 10(a) and 10(b), the positions of the outward projections 62 and 64 were the same for the first outward engaging portion 61 and the second outward engaging portion 63 when viewed from the extending direction of the rotation axis 50. In this embodiment, the positions of the outward projections 62 and 64 in the circumferential direction around the rotation axis 50 are different for the first outward engaging portion 61 and the second outward engaging portion 63 when viewed from the extending direction of the rotation axis 50. Therefore, the multiple sensor mounting angles corresponding to multiple angular positions when the sensor holder 5A is coupled to the mounting member 8A are different in the first and second orientations.

[0083] In the first modified example, as in the embodiment described above, the number of sensor mounting angles that can be adjusted with a single sensor holder 5A can be increased compared to the conventional method. Moreover, in the first modified example, multiple sensor mounting angles can be easily set by the difference in position between the outward projection 62 of the first outward engaging portion 61 and the outward projection 64 of the second outward engaging portion 63.

[0084] The second modified vehicle acceleration sensor 4B 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 the inclusion of one outward engaging portion 65, and 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 embodiment described above, the orientation of the sensor holder 5B when it is coupled to the mounting member 8B is reversed, resulting in either the first orientation shown in Figure 16(a) or the second orientation shown in Figure 16(b).

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

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

[0088] Similar to the above embodiment, the number of outward-facing protrusions 66 and inward-facing protrusions 87, 89 may be multiple. Alternatively, there may be multiple outward-facing protrusions 66 and one inward-facing protrusion 87, 89. Conversely, there may be multiple inward-facing protrusions 87, 89 and one outward-facing protrusion 66. Furthermore, in the second modification, similar to the above embodiment, the outward-facing engaging portion 65 may be asymmetrical with respect to the plane S1 that includes the center line 51a of the rotation axis 50 and the mounting surface 51.

[0089] In the above embodiment, as shown in Figures 10(a) and 10(b), the positions of the inward projections 87 and 89 were the same for the first inward engaging portion 86 and the second inward engaging portion 88 when viewed from the extending direction of the rotation axis 50. In this embodiment, the positions of the inward projections 87 and 89 in the circumferential direction around the rotation axis 50 are different for the first inward engaging portion 86 and the second inward engaging portion 88 when viewed from the extending direction of the rotation axis 50. Therefore, the multiple sensor mounting angles corresponding to multiple angular positions when the sensor holder 5B is coupled to the mounting member 8B are different in the first and second orientations.

[0090] In the second modified example, as in the above embodiment, the number of sensor mounting angles that can be adjusted with a single sensor holder 5B can be increased compared to the conventional method. Moreover, in this embodiment, multiple sensor mounting angles can be easily set by the difference in position between the inward projection 87 of the first inward engaging portion 86 and the inward projection 89 of the second inward engaging portion 88.

[0091] Furthermore, in the second modified example, the tip of the first support portion 58 is angled, while the tip of the second support portion 57 is flat, so the shape of the sensor holder 5B is asymmetrical with respect to the plane S2 which 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 third modified vehicle acceleration sensor 4C shown in Figures 17(a) and 17(b) includes a mounting member 8C configured in the same way as the mounting member 8 of the above embodiment, except for the first inward engaging portion 93 and the second inward engaging portion 95, and a sensor holder 5C configured in the same way as the sensor holder 5 of the above embodiment, except for the first outward engaging portion 6A and the second outward engaging portion 6C.

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

[0094] The first inward engaging portion 93 and the second inward engaging portion 95 each include at least one inwardly pointed projection 94, 96 that tapers radially inward around the rotation axis 50, similar to the inward engaging portions 86, 88 of the above embodiment. In this embodiment, the first inward engaging portion 93 is located outward from the second inward engaging portion 95 in the radial direction around the rotation axis 50.

[0095] The first outward-facing engagement portion 6A and the second outward-facing engagement portion 6C each include at least one outward-facing projection 6B, 6D that points radially outward around the rotation axis 50, similar to the outward-facing engagement portions 61, 63 of the above embodiment. In this embodiment, the first outward-facing engagement portion 6A is located outward from the second outward-facing engagement portion 6C in the radial direction around the rotation axis 50.

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

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

[0098] However, the positions in which the first outward engaging portion 6A and the second outward engaging portion 6C, and the first inward engaging portion 93 and the second inward engaging portion 95 are provided are not limited to the positions shown in Figures 17(a) and 17(b), but can be changed as appropriate. Also, in the third modified example, as in the above embodiment, the first outward engaging portion 6A and the second outward engaging portion 6C may each be asymmetrical with respect to the plane S1 that includes the center line 51a of the rotation axis 50 and the mounting surface 51.

[0099] Similar to the above embodiment, the number of outward-facing protrusions 6B, 6D and the number of inward-facing protrusions 94, 96 may be multiple. Alternatively, the number of outward-facing protrusions 6B, 6D may be multiple, and the number of inward-facing protrusions 94, 96 may be one. Conversely, the number of inward-facing protrusions 94, 96 may be multiple, and the number of outward-facing protrusions 6B, 6D may be one.

[0100] In the third modified example, as in the above embodiment, the multiple sensor mounting angles corresponding to multiple angular positions when the sensor holder 5C is coupled to the mounting member 8C are different in the first and second positions. Therefore, the number of sensor mounting angles that can be adjusted with a single sensor holder 5C can be increased compared to the conventional method. Moreover, in this embodiment, the first engagement structure of the first inward engaging portion 93 and the first outward engaging portion 6A and the second engagement structure of the second inward engaging portion 95 and the second outward engaging portion 6C can be made different. For example, the size and pitch of the outward and inward projections can be made different in the first engagement structure and the second engagement structure.

[0101] Furthermore, in the third modified example, 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. As a result, the shape of the sensor holder 5C is asymmetrical with respect to the plane S2 which 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.

[0102] In the above embodiment, the orientation of the sensor holder 5 when it is coupled to the mounting member 8 can be reversed. However, the orientation of the sensor holder 5 when it is coupled to the mounting member 8 cannot be reversed, and the mounting member 8 can be reversed relative to the housing 2 so that the sensor holder 5 can be attached to the housing 2 in either a first position or a second position. With this configuration, the orientation of the mounting member 8 when it is attached to the housing 2 can be used to select whether the sensor holder is in the first position or the second position. 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 parallel to the side plate 21 of the housing 2 and asymmetric with respect to the plane that includes the rotation axis 50, the mounting angles of multiple sensors will differ between the first position and the second position of the sensor holder 5.

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

[0104] In the above embodiment, the orientation of the sensor holder 5 was adjusted along a plane parallel to the back plate 23 of the housing 2. However, when the seat belt retractor 1 is tilted while the axial direction of the winding drum 3 remains horizontal, the tilt of the sensor holder 5, that is, the tilt 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 perpendicular to the axial direction of the winding drum 3 (in this case, the side plate 21). That is, as in the fourth modified vehicle acceleration sensor 4D shown in Figure 18 (Figure 18 is a view of the vehicle acceleration sensor 4D in the first position from the rear), 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 portion 82 and the second end portion 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 columns 58a of the first support portion 58, which pivotably 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, and a pair of support columns 57a of the second support portion 57, which pivotably supports a sensor lever (not shown) in the second position (similar to the above embodiment, this may be the same as or different from the sensor lever used in the first position), are provided at the front ends of both the first side wall 53 and the second side wall 54. For this reason, the fitting holes 57b and 58b provided in the support columns 57a and 58a are parallel to the rotation axis 50. That is, the oscillating shaft 42 is attached to the sensor holder 5D with its length parallel to the rotation axis 50.

[0106] In the fourth modified example, the orientation of the sensor holder 5D when it is coupled to the mounting member 8D is reversed, resulting in either the first or second orientation. Similar to the above embodiment, the multiple sensor mounting angles differ between the first and second orientations of the sensor holder 5D, allowing a single sensor holder 5D to accommodate a greater number of sensor mounting angles than conventional designs.

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

[0108] 1. Seat belt retractor 2 Housing 3 reel drums 4,4A~4D Vehicle acceleration sensor 41 Inertial mass body 5.5A~5D Sensor Holder 50 Rotation axis 51 Mounting surface 51a center line 57 Second support part 58 1st support part 61 First outward engaging portion 62 Outward-facing protrusions 63 Second outward engaging portion 64 Outward-facing projections 65 Outward-facing engagement portion 66 Outward-facing projections 6A First outward engaging portion 6B Outward-facing protrusion 6C Second outward engaging portion 6D Outward-facing protrusion 7A~7C Sensor Lever 8,8A~8D Mounting components 86 First inward engaging portion 87 Inward-facing projection 88 Second inward engaging portion 89 Inward-facing projection 91 Inward engaging portion 92 Inward-facing projection 93 First inward engaging portion 94 Inward-facing projection 95 Second inward engaging portion 96 Inward-facing projection

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 the orientation of the mounting member 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