Seat belt retractor and seat belt device

Abstract

Provided are a seat belt retractor and a seat belt device capable of suppressing an increase in frictional resistance during stable driving of a pretensioner and achieving an increase in resistance applied to a webbing during energy absorption. The seat belt retractor (1) comprises a guide member (7) disposed along an opening (32a) and facing at least a portion of an outer peripheral surface of a locking base (6), wherein the guide member (7) is configured not to contact the locking base (6) until the pretensioner (4) is switched to a stable driving state, is configured to contact the locking base (6) during stable driving of the pretensioner (4), and is configured to allow a locking tooth (32b) to contact the locking base (6) when a predetermined load is applied after the pretensioner (4) is switched to a stable driving state.

Description

Technical Field

[0001] The present invention relates to a seat belt retractor and a seat belt device, and more particularly to a seat belt retractor and a seat belt device capable of controlling load variation after a pretensioner is actuated. Background Art

[0002] Generally, a vehicle such as an automobile is provided with a seat belt device for restraining an occupant to a seat having a seat portion for the occupant to sit on and a backrest portion located at the back of the occupant. The seat belt device includes a webbing for restraining the occupant, a seat belt retractor for retracting the webbing, a buckle disposed on a side of the seat, and a tongue disposed on the webbing, and the occupant is restrained to the seat by the webbing by fitting the tongue into the buckle.

[0003] In addition, generally speaking, a seat belt retractor has a reel for winding up the webbing, a base frame that rotatably encloses the reel, a pretensioner that can wind up the webbing in an emergency, a locking mechanism that can stop the pulling out of the webbing, and a locking base that connects the reel and the locking mechanism.

[0004] The seatbelt retractor equipped with the above pretensioner has the following problem: in an emergency such as a vehicle collision, the rotation axis of the spool is eccentric when the pretensioner is activated, and the lock base contacts the lock teeth formed in the opening of the base frame, increasing the friction resistance.

[0005] In order to solve this problem, the invention described in Patent Document 1 includes a cover plate (26) provided on the outer periphery of a locking base (38) and a guide (30) supporting the locking base (38) in a rotatable manner. The locking base is equivalent to the locking base, and the cover plate is equivalent to the pretensioner cover.

[0006] Prior art literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-99943 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, when the upper body of the occupant moves forward, such as during a vehicle collision, a load greater than that when the pretensioner is in operation may be applied to the seatbelt retractor. In such a case, in order to absorb the energy generated by the occupant, it is sometimes better to pull the webbing out little by little while applying a certain degree of resistance.

[0010] However, in the invention described in the above-mentioned patent document 1, the guide member (30) is configured so that the locking base (38) and the internal teeth formed in the opening of the cover plate (26) are always in a non-contact state, so the resistance of the webbing during energy absorption may be insufficient.

[0011] The present invention has been conceived in view of the above-mentioned problems, and an object of the present invention is to provide a seatbelt retractor and a seatbelt device capable of suppressing an increase in frictional resistance during stable driving of a pretensioner and achieving an increase in resistance applied to a webbing during energy absorption.

[0012] Means for solving problems

[0013] According to the present invention, a seat belt retractor is provided, comprising: a spool for reeling up a webbing for restraining an occupant; a base frame for rotatably enclosing the spool; a pretensioner for reeling up the webbing in an emergency; a locking mechanism for stopping the pulling out of the webbing; and a locking base for connecting the spool and the locking mechanism, wherein the seat belt retractor is characterized in that the base frame comprises: an opening for inserting the locking base; a locking tooth formed on the inner periphery of the opening and capable of being locked with a part of the locking mechanism; and a guide member opposed to at least a part of the outer peripheral surface of the locking base and arranged along the opening, the guide member being configured not to contact the locking base until the pretensioner is switched to a stable driving state, being configured to contact the locking base during stable driving of the pretensioner, and being configured to allow the locking tooth to contact the locking base when a predetermined load is applied after the pretensioner is switched to a stable driving state.

[0014] The guide member may be configured to be plastically deformed when the predetermined load is applied thereto.

[0015] Alternatively, the guide member may include a main body portion having a gap α with the locking base in an initial state, and an extension portion adjacent to an upstream side of the main body portion and having a gap δ with the locking base, and have a relationship of α≤β<δ relative to the gap β between the locking base and the opening portion.

[0016] The guide member may include a front end portion adjacent to the upstream side of the extension portion and having a gap ε between the front end portion and the lock base, so that a relationship of ε>δ is established.

[0017] The front end portion may include a tapered surface inclined toward the upstream side.

[0018] The guide member may include a plurality of fixing terminals disposed on the main body portion and the extension portion.

[0019] The guide member may be configured so that a predetermined gap γ exists between a back surface of the guide member and the base frame.

[0020] The seatbelt retractor may include a ring gear disposed on a shaft portion of the lock base that is rotated by operation of the pretensioner, and the guide member may be disposed in a region opposite to a portion where a power transmission member of the pretensioner rotates the ring gear.

[0021] Furthermore, according to the present invention, there is provided a seat belt device characterized by including a seat belt retractor having any one of the above-mentioned structures.

[0022] Effects of the Invention

[0023] According to the seat belt retractor and seat belt device of the present invention, by arranging a guide member at a position opposite to the outer peripheral surface of the locking base, even if the rotating axis of the spool is eccentric during stable driving of the pretensioner, the contact between the locking base and the locking teeth can be limited by the contact between the locking base and the guide member, thereby suppressing the increase of frictional resistance.

[0024] Furthermore, since the guide member is configured to allow the lock base to contact the lock teeth when a predetermined load is applied after the pretensioner is switched to the stable driving state, it is possible to increase the resistance applied to the webbing when absorbing the energy of the occupant after the pretensioner is operated. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a component development view showing a seatbelt retractor according to an embodiment of the present invention.

[0026] Figure 2 These are enlarged views of the guide member, (A) is a perspective view showing the front side, and (B) is a perspective view showing the back side.

[0027] Figure 3 2 are cross-sectional views showing an initial state, (A) is a cross-sectional view showing a plane including the ring gear, and (B) is a cross-sectional view showing a plane including the guide member.

[0028] Figure 4 is an explanatory diagram showing the function of the guide member, (A) shows Figure 3 The initial state of the AA line cross-sectional view in (B) shows Figure 3 (B) shows the initial state of the BB line cross-sectional view, and (C) shows Figure 3 (B) shows the stable driving state of the AA line cross-sectional view, and (D) shows Figure 3 (B) Load loading state of the AA line cross-sectional view.

[0029] Figure 5 1 and 2 are diagrams showing an operation start state of the pretensioner, wherein (A) is a cross-sectional view taken along a plane including the ring gear, and (B) is a cross-sectional view taken along a plane including the guide member.

[0030] Figure 6 1 and 2 are diagrams showing a stable driving state of a pretensioner, wherein (A) is a cross-sectional view taken along a plane including the ring gear, and (B) is a cross-sectional view taken along a plane including a guide member.

[0031] Figure 7 1 and 2 are explanatory diagrams showing the function of the front end portion of the guide member, wherein (A) shows the relationship with the power transmission member, and (B) shows the relationship with the lock base.

[0032] Figure 8 1 is a diagram showing the overall configuration of a seat belt device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] Below, use Figures 1 to 8 Here, the embodiments of the present invention are described. Figure 1 It is a component development view showing a seatbelt retractor according to an embodiment of the present invention. Figure 2 These are enlarged views of the guide member, (A) is a perspective view showing the front side, and (B) is a perspective view showing the back side. Figure 3 are cross-sectional views showing the initial state, (A) is a cross-sectional view showing a plane including the gear ring, and (B) is a cross-sectional view showing a plane including the guide member. Figure 3 In (B), for the sake of convenience of explanation, the lock base 6 is shown in gray.

[0034] For example Figure 1 As shown, a seat belt retractor 1 involved in one embodiment of the present invention comprises: a reel 2 for reeling in a webbing for restraining an occupant; a base frame 3 for rotatably enclosing the reel 2; a pretensioner 4 for reeling in an emergency; a locking mechanism 5 for stopping the pulling out of the webbing; and a locking base 6 for connecting the reel 2 and the locking mechanism 5, the base frame 3 comprises: an opening 32a for inserting the locking base 6; locking teeth 32b formed on the inner periphery of the opening 32a and capable of being locked with a part of the locking mechanism 5; a guide member 7 opposed to at least a part of the outer peripheral surface of the locking base 6 and arranged along the opening 32a; and a spring unit 8 for applying a force in the reel 2 in the reeling direction.

[0035] The reel 2 is a reel for winding the webbing, and is rotatably housed in a base frame 3 forming the framework of the seat belt retractor 1. The base frame 3 is composed of, for example, a pair of opposing first end faces 31 and second end faces 32 and a side face 33 connecting the first end face 31 and the second end face 32, and has a so-called square U-shape. The base frame 3 may also include a connecting plate 34 that is opposite to the side face 33 and connected to the first end face 31 and the second end face 32.

[0036] In addition, in the seat belt retractor 1 according to the present embodiment, the spring unit 8 is arranged on the first end surface 31 side, and the pretensioner 4 and the locking mechanism 5 are arranged on the second end surface 32 side. In addition, the arrangement of the spring unit 8, the pretensioner 4, the locking mechanism 5, etc. is not limited to the structure shown in the figure. For example, the pretensioner 4 and the spring unit 8 may be arranged on the first end surface 31 side, and the locking mechanism 5 may be arranged on the second end surface 32 side.

[0037] The first end surface 31 of the base frame 3 is formed with an opening 31a through which the shaft portion of the reel 2 is inserted, and the second end surface 32 of the base frame 3 is formed with an opening 32a having a locking tooth 32b that can be engaged with a ratchet (not shown) of the locking mechanism 5. In addition, a pretensioner cover 47 that forms a passage for the power transmission member 42 of the pretensioner 4 is arranged on the inner surface (the surface on the side opposite to the first end surface 31) of the second end surface 32 of the base frame 3. In addition, the locking mechanism 5 is arranged on the outer surface (the surface on the back side of the inner surface) of the second end surface 32 of the base frame 3, and the locking mechanism 5 is accommodated in the retainer cover 51.

[0038] The retaining ring cover 51 may also be provided with a vehicle sensor 9 for detecting a sudden deceleration or tilt of the vehicle body. The vehicle sensor 9 may include, for example, a spherical mass body and a sensor rod that swings due to the movement of the mass body. In addition, the vehicle sensor 9 may also be embedded in and fixed to an opening formed on the second end surface 32 of the base frame 3.

[0039] The spool 2 has a hollow at the center, for example, through which a torsion bar 21 forming an axis is inserted. The first end of the torsion bar 21 is connected to a spring core (not shown) of the spring unit 8, and the second end is connected to the lock base 6. Therefore, the spool 2 is configured to rotate together with the torsion bar 21 and the lock base 6 in normal times.

[0040] The structure of the spool 2 is not limited to the above structure, and the torsion bar 21 may be omitted as needed. The means for applying the winding force to the spool 2 is not limited to the spring means 8, and may be other means using an electric motor or the like.

[0041] The locking base 6 includes, for example, a shaft portion 61 inserted through and fixed to the opening of the winding shaft 2, a flange portion 62 having a larger diameter than the opening 32a formed on the second end surface 32 of the base frame 3, and a convex portion 63 having a substantially cylindrical or cylindrical shape inserted through the opening 32a. A gear ring 41 that rotates as the pretensioner 4 operates is disposed between the winding shaft 2 and the flange portion 62 of the locking base 6.

[0042] The flange portion 62 is a portion that functions as a portion preventing the locking base 6 from coming off, and therefore has a diameter larger than the aperture of the opening portion 32a of the base frame 3. A ratchet (not shown) is disposed on the convex portion 63 so as to be able to come out and go out from the side portion. When the locking mechanism 5 is in operation, the ratchet protrudes from the side portion of the convex portion 63 and is engaged with the locking teeth 32b formed in the opening portion 32a of the base frame 3, thereby restricting the rotation of the locking base 6 in the webbing pulling direction.

[0043] Therefore, when the locking mechanism 5 is in operation, even when a load is applied in the webbing pulling direction, the spool 2 can be kept in a non-rotating state until a load exceeding a threshold value is generated on the torsion bar 21. Furthermore, when a load exceeding a threshold value is generated on the torsion bar 21, the torsion bar 21 is twisted, the spool 2 relatively rotates, and the webbing is pulled out.

[0044] Although not shown in detail, the locking mechanism 5 includes, for example, a locking gear disposed adjacent to the locking base 6, a flywheel disposed on the locking gear in a swingable manner, and a retainer cover 51 that accommodates the locking gear and the flywheel. When the webbing is pulled out faster than normal, the flywheel swings and engages with the internal teeth formed on the wall member erected on the retainer cover 51. When the vehicle sensor 9 is operated, the sensor lever thereof engages with the external teeth formed on the outer peripheral surface of the locking gear.

[0045] Thus, the rotation of the lock gear is restricted by the operation of the flywheel or the vehicle sensor 9. When the rotation of the lock gear is restricted, relative rotation occurs between the lock base 6 and the lock gear, and the ratchet protrudes from the side surface of the protrusion 63 in accordance with the relative rotation.

[0046] The locking mechanism 5 is not limited to the above-mentioned structure, and any of various existing locking mechanisms can be used. In addition, the spool 2 may include a shock absorbing mechanism composed of a combination of a shaft and a linear or plate-shaped plastic deformation member instead of the torsion bar 21 .

[0047] The pretensioner 4 includes, for example, a ring gear 41 disposed on the shaft portion 61 of the lock base 6, a power transmission member 42 that rotates the ring gear 41, a tube 43 that accommodates the power transmission member 42 and guides its movement, a gas generator 44 that applies a propulsive force to the power transmission member 42, a piston 45 that is disposed at the rear end of the power transmission member 42 and seals a gap between the power transmission member 42 and the tube 43, a guide block 46 that is disposed at the front end of the tube 43 and guides the power transmission member 42 toward the ring gear 41, and a pretensioner cover 47 that accommodates the ring gear 41 and forms a passage for the power transmission member 42. In addition, the ring gear 41 is sometimes referred to as a drive wheel or a rotating member.

[0048] The power transmission member 42 has a long and thin rod shape made of resin, for example, and is configured to move while biting into the teeth of the ring gear 41 and being plastically deformed, thereby rotating the ring gear 41 .

[0049] The structure of the pretensioner 4 is not limited to the above-mentioned structure. For example, a metal sphere or a rod-shaped rack may be used as the power transmission member 42. In addition, the pretensioner 4 may be a structure in which the movement of the power transmission member 42 is guided by a portion obtained by extending a portion of the tube 43 instead of the guide block 46.

[0050] In addition, in the present embodiment, the pretensioner 4 is shown as being arranged on the inner surface side (the side opposite to the first end surface 31) of the base frame 3, but the pretensioner 4 may be arranged on the outer surface side (the side of the second end surface 32 where the locking mechanism 5 is arranged) of the base frame 3. In this case, the pretensioner cover 47 is arranged on the outer side of the second end surface 32 of the base frame 3.

[0051] For example Figure 2 (A) and Figure 2 As shown in (B), the guide member 7 has a substantially partial annular shape. Here, "substantially partial annular shape" means that it is a partial annular shape as a whole. In addition, the guide member 7 can also be a casting (die-casting product) formed by pressing an alloy such as aluminum into a mold.

[0052] For example Figure 3 As shown in (B), the guide member 7 comprises: a main body portion 71, which has a gap α between it and the flange portion 62 of the locking base 6 in the initial state; an extension portion 72, which is adjacent to the upstream side of the main body portion 71 and has a gap δ between it and the flange portion 62 of the locking base 6; and a front end portion 73, which is adjacent to the upstream side of the extension portion 72 and has a gap ε between it and the flange portion 62 of the locking base 6.

[0053] In the present embodiment, the “upstream side” means the upstream side in the moving direction of the power transmission member 42. In the present embodiment, the “initial state” means the state before the pretensioner 4 is operated or the state in which the pretensioner is assembled.

[0054] In addition, if Figure 3 As shown in (B), the guide member 7 is fixed to the second end surface 32 of the base frame 3 in a manner facing the outer peripheral surface of the flange portion 62 of the lock base 6. The guide member 7 is a component that restricts the movement of the lock base 6 when the pretensioner 4 is working, and is therefore arranged in a region opposite to the portion (entry position) where the power transmission member 42 and the ring gear 41 bite into each other. At this time, the main body 71 is arranged in a direction in which the rotation axis of the spool 2 is eccentric when the pretensioner 4 is stably driven, and the extension portion 72 is arranged in a direction in which the rotation axis of the spool 2 is eccentric when the pretensioner 4 is started.

[0055] In addition, if Figure 2 As shown in (B), the guide member 7 may also include a plurality of fixed terminals 74 disposed on the main body 71 and the extension 72. The fixed terminal 74 is, for example, a protrusion formed on the back of the guide member 7. The fixed terminal 74 is inserted into the through hole 32c formed on the second end surface 32 of the base frame 3 and then riveted, and the guide member 7 is fixed to the base frame 3. By disposing a plurality of fixed terminals 74 on the guide member 7 in this way, it can be stably and firmly fixed to the base frame 3.

[0056] However, the fixing method of the guide member 7 is not limited to "riveting" (pressing to plastically deform it), and it can also be fixed by bolts, pins, adhesives, etc. In addition, the guide member 7 is a member for adjusting the narrow gap α with the locking base 6 and is a member that requires a certain load resistance, so it is best to use riveting with excellent positioning accuracy and strength.

[0057] Here, if Figure 3 As shown in (B), the sizes of the gap α, the gap δ and the gap ε have a relationship of α<δ<ε. In addition, if the gap between the protrusion 63 of the locking base 6 and the locking tooth 32b of the opening 32a formed in the base frame 3 (second end surface 32) is set to β, then the relationship of α≤β<δ is achieved.

[0058] First, regarding the role of the gap α of the main body 71 and the gap δ of the extension 72, referring to Figure 4 (A)~ Figure 6 (B) is explained. Figure 4 is an explanatory diagram showing the function of the guide member, (A) shows Figure 3 The initial state of the AA line cross-sectional view in (B) shows Figure 3 (B) shows the initial state of the BB line cross-sectional view, and (C) shows Figure 3 (B) shows the stable driving state of the AA line cross-sectional view, and (D) shows Figure 3 (B) is the load state of the AA line cross-sectional view. Figure 4 (A)~ Figure 4 In (D), for convenience of explanation, the guide member 7 is shown in gray.

[0059] like Figure 4 As shown in (A), in the initial state, there is a gap δ between the extension portion 72 of the guide member 7 and the flange portion 62 of the lock base 6. At this time, a gap β is formed between the protrusion 63 of the lock base 6 and the front end of the lock tooth 32b of the opening portion 32a formed in the base frame 3 (second end surface 32).

[0060] The size of the gap δ and the gap β have a relationship of δ>β. Therefore, it is designed that: even if the lock base 6 is pressed by the power transmission member 42 and moves upward in the figure when the pretensioner 4 is working, the convex portion 63 may contact the locking tooth 32b, but the flange portion 62 does not contact the guide member 7 (extension portion 72).

[0061] Here, Figure 5 1 is a diagram showing the working start state of the pretensioner, (A) is a cross-sectional view of a plane including the gear ring, and (B) is a cross-sectional view of a plane including the guide member. Figure 5 In (B), for the sake of convenience of explanation, the lock base 6 is shown in gray.

[0062] If the pretensioner 4 is activated, Figure 5 As shown in (A), the power transmission member 42 is pushed out from the tube 43, deflected by the guide block 46, and collides with the teeth of the ring gear 41. At this time, the propulsion force Fd of the power transmission member 42 generates a load Fp in the lower left direction in the figure (approximately in the direction of 8 o'clock if expressed by the short hand of a clock) on the ring gear 41.

[0063] Since the gear ring 41 is fixed to the shaft portion 61 of the locking base 6, Figure 5 As shown in FIG. 2B , the lock base 6 moves toward the lower left direction of the figure (approximately the 8 o'clock direction if expressed by the short hand of a clock) by the load Fp. At this time, the extension portion 72 or the front end portion 73 of the guide member 7 is present in the moving direction of the load Fp, so the flange portion 63 of the lock base 6 is configured not to contact the guide member 7.

[0064] When the pretensioner 4 is started, a larger load is applied than when it is driven steadily. Therefore, if the guide member 7 is used to receive the load, the impact on the guide member 7 becomes larger, and a countermeasure is required. In addition, even if the locking base 6 contacts the locking teeth 32b of the base frame 3 when the pretensioner 4 is started, it is only temporary and has little effect on the performance of the pretensioner 4.

[0065] like Figure 4 As shown in (B), in the initial state, there is a gap α between the main body 71 of the guide member 7 and the flange 62 of the lock base 6. At this time, a gap β is formed between the protrusion 63 of the lock base 6 and the front end of the lock tooth 32b of the opening 32a formed in the base frame 3 (second end surface 32).

[0066] The size of the gap α and the gap β has a relationship of α≤β. In addition, the figure shows the case of α<β. Therefore, it is designed that when the locking base 6 is pressed by the power transmission member 42 and moves upward in the figure during the operation of the pretensioner 4, the flange portion 62 contacts the guide member 7 (main body 71) and the protrusion 63 does not contact the locking tooth 32b.

[0067] In addition, if Figure 4 As shown in (B), the back surface of the guide member 7 is configured to have a predetermined gap γ with the connection plate 34 constituting the base frame 3. By forming the gap γ, a space capable of plastically deforming the guide member 7 toward the connection plate 34 can be ensured as described later.

[0068] Here, Figure 6 1 is a diagram showing a stable driving state of the pretensioner, (A) is a cross-sectional view of a plane including the ring gear, and (B) is a cross-sectional view of a plane including the guide member. Figure 6 In (B), for the sake of convenience of explanation, the lock base 6 is shown in gray.

[0069] After the pretensioner 4 is activated, if the power transmission member 42 moves further, Figure 6 As shown in (A), the power transmission member 42 enters between the ring gear 41 and the guide block 46, and rotates the ring gear 41 while being plastically deformed. In this specification, this state is referred to as a "stable drive state". In this stable drive state, because the power transmission member 42 is pushed into the narrow gap between the ring gear 41 and the guide block 46, the thrust force Fd of the power transmission member 42 generates a load Fv in a direction approximately perpendicular to the entry direction of the power transmission member 42 (approximately 10 o'clock direction if expressed by the short hand of a clock) on the ring gear 41.

[0070] Since the gear ring 41 is fixed to the shaft portion 61 of the locking base 6, Figure 6 As shown in (B), the lock base 6 moves in a direction perpendicular to the entry direction of the power transmission member 42 (approximately 10 o'clock direction if expressed by the short hand of a clock) by the load Fv. Figure 4 As shown in (C), the lock base 6 moves toward the guide member 7, the gap α disappears (α=0), the flange portion 62 contacts the main body portion 71 of the guide member 7, and the movement of the lock base 6 is restricted.

[0071] In addition, when a predetermined load is generated on the guide member 7 during or after stable driving, the guide member 7 is plastically deformed, the gap β disappears (β=0), and the contact between the lock tooth 32b and the lock base 6 is allowed. At this time, it is designed that the gap γ formed on the back side of the guide member 7 does not disappear even when the guide member 7 is plastically deformed.

[0072] In this way, by forming the guide member 7 to be able to plastically deform under a predetermined load, for example, when the upper body of the occupant moves forward as in a vehicle collision and a load greater than that generated when the pretensioner 4 is in operation is generated on the seatbelt retractor 1, in order to absorb the energy generated by the occupant, the webbing can be pulled out little by little while applying a certain degree of resistance to the webbing.

[0073] According to the seat belt retractor 1 involved in the above-mentioned present embodiment, by configuring the guide member 7 at a position opposite to the outer peripheral surface of the locking base 6, even if the rotation axis of the spool 2 is eccentric during stable driving of the pretensioner 4, the contact between the locking base 6 and the locking tooth 32b can be limited by the contact between the locking base 6 and the guide member 7, thereby suppressing the increase of friction resistance.

[0074] Furthermore, the guide member 7 is configured to allow the lock base 6 to contact the lock teeth 32b when a predetermined load is applied after the pretensioner 4 is switched to the stable driving state, thereby increasing the resistance applied to the webbing when the occupant's energy is absorbed after the pretensioner 4 is completed.

[0075] However, in order to achieve the purpose of the present invention, it is also conceivable to restrict the contact between the lock base 6 and the lock tooth 32 b until the operation of the pretensioner 4 is completed, and allow the contact between the lock base 6 and the lock tooth 32 b after the operation of the pretensioner 4 is completed.

[0076] In this case, it is difficult to manage the timing of bringing the lock base 6 into contact with the lock tooth 32b, and the effect of increasing the resistance during energy absorption may become unstable. Therefore, in this embodiment, in order to stabilize the effect of increasing the resistance during energy absorption, the value of the predetermined load at which the guide member 7 can be plastically deformed is set so that the lock base 6 and the lock tooth 32b can be in contact at the time point when the pretensioner 4 is transformed into a stable driving state.

[0077] Next, regarding the function of the front end portion 73 of the guide member 7, Figure 2 (A) Figure 7 (A) and Figure 7 (B) Explain. Here, Figure 7 1 is an explanatory diagram showing the function of the front end portion of the guide member, (A) shows the relationship with the power transmission member, and (B) shows the relationship with the locking base. Figure 7 (A) and Figure 7 (B) Yes Figure 3 (B) is a CC cross-sectional view. In each figure, for the sake of convenience of explanation, the guide member 7 is shown in gray. In each figure, the fixed terminal 74 is shown in a state before caulking.

[0078] The front end portion 73 has a tapered surface 73a inclined toward the upstream side. The tapered surface 73a is formed to mitigate the impact caused by the collision between the moving power transmission member 42 and the guide member 7. Therefore, the tapered surface 73a is formed in a manner exposed to the passage side of the power transmission member 42, such as Figure 7 As shown in (A), it is formed at a portion that the front end of the power transmission member 42 may contact. In addition, for the convenience of explanation, the power transmission member 42 is shown in the figure with a single-dot chain line.

[0079] In addition, if Figure 7 As shown in FIG. 2B , the size of the gap ε is designed so that the flange 62 of the lock base 6 does not contact the guide member 7 even when the rotation axis of the spool 2 is eccentric. For convenience of explanation, the lock base 6 having the flange 62 is shown in dashed lines.

[0080] In this way, by extending a portion of the guide member 7 near the entrance of the passage of the power transmission member 42 to form the front end portion 73 having the tapered surface 73a, the impact caused by the collision between the guide member 7 and the power transmission member 42 can be mitigated, and the movement of the power transmission member 42 can be stabilized. In addition, the extension portion 72 can be formed between the front end portion 73 and the main body 71, and the fixed terminal 74 can also be arranged in a balanced manner.

[0081] Next, with reference to the seat belt device according to one embodiment of the present invention, Figure 8 Here, Figure 8 1 is a diagram showing the overall structure of a seat belt device according to an embodiment of the present invention. Figure 8 In the figure, for convenience of explanation, components other than the seat belt device are shown with a single-dot chain line.

[0082] Figure 8 The seat belt device 100 according to the present embodiment shown in the figure comprises: a webbing W for restraining an occupant, a seat belt retractor 1 for retracting the webbing W, a guide anchor 101 provided on the vehicle body side and guiding the webbing W, a belt anchor 102 for fixing the webbing W to the vehicle body side, a buckle 103 provided on the side surface of the seat S, and a tongue 104 provided on the webbing W. The seat belt retractor 1 has, for example, Figure 1 The structure shown.

[0083] The components other than the seat belt retractor 1 are briefly described below. The seat S includes, for example, a seat portion S1 for an occupant to sit on, a backrest portion S2 located at the back of the occupant, and a headrest portion S3 for supporting the head of the occupant. The seat belt retractor 1 is, for example, built into a B-pillar P of a vehicle body. In addition, generally speaking, the buckle 103 is often arranged on the side of the seat portion S1, and the belt anchor 102 is often arranged on the lower surface of the seat portion S1. In addition, the guide anchor 101 is often arranged on the B-pillar P. In addition, one end of the webbing W is connected to the belt anchor 102, and the other end is connected to the seat belt retractor 1 via the guide anchor 101.

[0084] Therefore, when the tongue 104 is fitted into the buckle 103, the webbing W is pulled out from the seat belt retractor 1 while sliding in the insertion hole of the guide anchor 101. In addition, when the occupant wears the seat belt or releases the seat belt when getting off the vehicle, the spring unit 8 of the seat belt retractor 1 acts to reel the webbing W until a certain load acts.

[0085] The seat belt device 100 described above applies the seat belt retractor 1 according to the above embodiment to a conventional seat belt device for a front seat. Therefore, according to the seat belt device 100 according to this embodiment, the eccentricity of the rotating shaft of the spool 2 including the lock base 6 can be adjusted by the guide member 7, and the increase of the friction resistance during the stable driving of the pretensioner 4 can be suppressed, and the increase of the resistance applied to the webbing W during energy absorption can be achieved.

[0086] The seat belt device 100 according to the present embodiment is not limited to application to front seats, and can be easily applied to rear seats by omitting the guide anchor 101. The seat belt device 100 according to the present embodiment can also be used in transportation vehicles other than vehicles.

[0087] The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present invention.

[0088] Description of Reference Numerals

[0089] 1 seat belt retractor, 2 reel, 3 base frame, 4 pretensioner, 5 locking mechanism, 6 locking base, 7 guide member, 8 spring unit, 9 vehicle sensor, 21 torsion bar, 31 first end surface, 31a opening portion, 32 second end surface, 32a opening portion, 32b locking tooth, 32c through hole, 33 side surface, 34 connecting plate, 41 ring gear, 42 power transmission member, 43 pipe, 44 gas generator, 45 piston, 46 guide block, 47 pretensioner cover, 51 retaining ring cover, 61 shaft portion, 62 flange portion, 63 convex portion, 71 main body portion, 72 extension portion, 73 front end portion, 73a tapered surface, 74 fixed terminal, 100 seat belt device, 101 guide anchor, 102 belt anchor, 103 buckle, 104 tongue.

Claims

1. A seat belt retractor, comprising: a reel for reeling up a webbing for restraining an occupant; a base frame for rotatably enclosing the reel; a pretensioner for reeling up the webbing in an emergency; a locking mechanism for stopping the webbing from being pulled out; and a locking base for connecting the reel and the locking mechanism, wherein the seat belt retractor is characterized in that: The base frame comprises: an opening portion through which the locking base is inserted; a locking tooth formed on the inner periphery of the opening portion and capable of being locked with a portion of the locking mechanism; and a guide member facing at least a portion of the outer peripheral surface of the locking base and arranged along the opening portion, The guide member is configured not to contact the locking base until the pretensioner is switched to a stable driving state, is configured to contact the locking base during stable driving of the pretensioner, and is configured to allow the locking tooth to contact the locking base when a predetermined load is applied after the pretensioner is switched to a stable driving state.

2. The seat belt retractor according to claim 1, in, The guide member is configured to be plastically deformed when the predetermined load is applied thereto.

3. The seat belt retractor according to claim 1, in, The guide member includes a main body portion having a gap α with the lock base in an initial state, and an extension portion adjacent to the upstream side of the main body portion and having a gap δ with the lock base, and has a relationship of α≤β<δ relative to the gap β between the lock base and the opening portion.

4. The seat belt retractor according to claim 3, in, The guide member includes a front end portion adjacent to the upstream side of the extension portion and having a gap ε between the front end portion and the lock base, and has a relationship of ε>δ.

5. The seat belt retractor according to claim 4, in, The front end portion includes a tapered surface inclined toward the upstream side.

6. The seat belt retractor according to claim 3, in, The guide member includes a plurality of fixing terminals disposed on the main body portion and the extension portion.

7. The seat belt retractor according to claim 1, in, The guide member is configured to have a predetermined gap γ between the back surface thereof and the base frame.

8. The seat belt retractor according to claim 1, in, A ring gear that rotates by the operation of the pretensioner is disposed on the shaft portion of the lock base, and the guide member is disposed in a region opposite to a portion where a power transmission member of the pretensioner rotates the ring gear.

9. A seat belt device, It is characterized in that A seat belt retractor comprising the seat belt retractor according to any one of claims 1 to 8.

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