WO2013061873A1

WO2013061873A1 - Seatbelt retractor

Info

Publication number: WO2013061873A1
Application number: PCT/JP2012/077080
Authority: WO
Inventors: 智角中; 仁洙崔
Original assignee: 芦森工業株式会社
Priority date: 2011-10-28
Filing date: 2012-10-19
Publication date: 2013-05-02

Abstract

A clutch for operating a pawl has a pilot lever support section which is provided in a protruding manner so as to face the outer peripheral surface of the shaft section of a pilot lever, the shaft section being inserted in and fitted to a mounting boss, the outer peripheral surface of the shaft section being on the opposite side of the shaft section from an engagement claw section, and the pilot lever support section forms a predetermined gap with the outer peripheral surface of the shaft section. The pilot lever is configured so that, in a normal state, the outer peripheral surface of the shaft section which is inserted in and fitted to the mounting boss forms the predetermined gap with the pilot lever support section to allow the engagement claw section to rotate under the own weight thereof, and so that, in an emergency, if the engagement claw section is engaged with a locking gear by the pivoting of a sensor lever and the mounting boss is deflected by being pressed by the rotation of the locking gear in the webbing extraction direction, the clutch is caused to pivot in response to the pivoting of the locking gear while the outer peripheral surface of the shaft section is in contact with the pilot lever support section.

Description

Seat belt retractor

The present invention relates to a seat belt retractor for preventing webbing from being pulled out in an emergency.

Conventionally, various seat belt retractors for preventing webbing from being pulled out in an emergency have been proposed.
For example, in the webbing take-up device disclosed in Japanese Patent Laid-Open No. 2006-188148, the V gear 126 of the pressing portion 168 protruding toward the V gear 126 side is provided at the lower end portion of the main body portion 130 of the sensor gear 128. A shaft 129 is formed so as to protrude from the opposite end. Further, an engaging claw 140 as a connecting member is pivotally supported on the shaft 129 so as to be rotatable. In addition, an acceleration sensor 142 is provided below the engaging claw 140, and the vehicle is suddenly decelerated. When the sensor claw 152 of the acceleration sensor 142 is pushed up by the hard ball 148, the engaging claw 140 is moved upward. Rotate.

Further, a V gear 126 having ratchet teeth formed on the outer peripheral portion is located on the rotation direction side of the engagement claw 142 rotated upward by the sensor claw 152, whereby the engagement claw 142 is Engage with the V gear 126. When the engaging claw 142 engages with the V gear 126, the rotational force of the V gear 126 in the webbing pull-out direction is transmitted to the sensor gear 128, and the pressing portion 168 rotates the lock pawl 160. When the lock pawl 160 is rotated, the pawl portion 166 is engaged with the ratchet portion 172 of the lock base 170, and the rotation of the spool 24 in the webbing pull-out direction is prevented.

In the conventional webbing take-up device described above, a large pressing load in the direction of the shaft 129 acts on the engaging claw 140 engaged with the V gear 126 due to the rotational force of the V gear 126 in the webbing pull-out direction. For this reason, the main body 130 of the sensor gear 128 has an engagement claw 140 engaged with the V gear 126 so that the engagement claw 140 supported by the shaft 129 can withstand the pressing load received from the V gear 126. A substantially L-shaped load support portion is provided so as to be fitted between the claw portion and the shaft portion and receive a pressing load via the claw portion.

However, in order to improve the sensitivity of the acceleration sensor 142, it is necessary to reduce the size of the engaging claw 140 to reduce the mass. However, the engaging claw 140 is substantially L-shaped between the claw portion and the shaft portion. Therefore, there is a problem that it is difficult to reduce the overall length of the claw portion by making it shorter. Further, in order to reduce the mass of the engaging claw 140 having a long overall length, the engaging claw 140 is formed in a thin shape as a whole, and there is a problem that it is difficult to reduce the size while ensuring sufficient strength. .

In the conventional webbing take-up device described above, the engaging claw 140 has a claw portion that engages with the V gear 126 projecting radially outward from the outer peripheral surface of the shaft portion into which the shaft 129 is inserted. Further, the engaging claw 140 has a V-gear of the pressing portion 168 at the distal end portion of the elastic locking piece that extends in a generally fan shape from the outer peripheral surface on the opposite side in the radial direction of the shaft portion to the claw portion. An engagement protrusion is formed which is elastically locked to an arcuate engagement hole formed on the end surface portion opposite to 126. Then, the engaging claw 140 is inserted into the shaft 129 and pushed, and the engaging projection formed at the tip of the elastic locking piece is elastically locked in the engaging hole of the pressing portion 168. And attached to the sensor gear 128 while being supported by the shaft 129.

However, in order to reduce the resistance force when the engaging claw 140 is rotated upward by the engaging claw 152 of the acceleration sensor 142, the engaging claw 140 and the elastic locking piece extending outward from the outer peripheral surface of the shaft portion are elastic. There is a problem that it is necessary to increase the dimensional accuracy of the parts such as the engagement protrusion formed at the tip end portion of the locking piece and the sensor gear 128, thereby increasing the cost. Further, the shape of the entire part such as the engaging claw 140 and the sensor gear 128 becomes complicated, and there is a problem that quality control and assembly work of the shape become complicated.

Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a seatbelt retractor that can be downsized while ensuring sufficient strength of a pilot lever. To do. Another object of the present invention is to provide a seatbelt retractor that can simplify the shape of a part and can simplify the quality control and assembly work of the shape.

To achieve the above object, a seatbelt retractor according to the present invention includes a housing, a winding drum that is rotatably housed in the housing and winds and stores a webbing, and a ratchet gear that rotates integrally with the winding drum. A locking mechanism for preventing the winding drum from rotating in the webbing pull-out direction in an emergency, an inertial mass body that swings in response to an acceleration of a predetermined value or more of the vehicle, and a swinging mechanism that is pushed by the inertial mass body. A sensor lever that moves to activate the lock mechanism, and the lock mechanism is rotatably arranged coaxially with the take-up drum, and engages with the ratchet gear by rotation to engage the winding mechanism. A clutch that guides a pawl that prevents rotation of the take-up drum in the webbing pull-out direction, and the sensor lever that is pivotally supported by a mounting boss that is erected on the clutch and swings. A pilot lever that is pressed and rotated, and a locking gear that is integrally and coaxially attached to the winding drum and that is engaged with the pilot lever by rotation. A cylindrical shaft portion that is rotatably fitted to the mounting boss, and an engagement claw portion that protrudes from an outer peripheral surface of the shaft portion and engages with the locking gear; A pilot lever support portion projecting so as to be opposed to the outer peripheral surface on the opposite side in the radial direction with respect to the engaging claw portion of the shaft portion fitted into the mounting boss; In the pilot lever, the outer peripheral surface of the shaft portion that is normally inserted into the mounting boss forms a predetermined gap with the pilot lever support portion, and the engagement claw portion rotates by its own weight. By swinging the sensor lever When the engaging claw engages with the locking gear and is pressed by the rotation of the locking gear in the webbing pull-out direction and the mounting boss is bent, the outer peripheral surface of the shaft portion is the pilot. The clutch is rotated according to the rotation of the locking gear while being in contact with the lever support portion.

In such a seat belt retractor, the pilot lever is rotatably inserted into a mounting boss having a cylindrical shaft portion standing on the clutch. In the pilot lever, the outer peripheral surface of the shaft portion inserted into the mounting boss normally forms a predetermined gap with the pilot lever support portion protruding from the clutch, and the engaging claw portion rotates by its own weight. Yes. In addition, when the pilot lever is urged by the rotation of the locking gear in the webbing pull-out direction and the mounting boss is bent when the engaging claw is engaged with the locking gear by the swing of the sensor lever in an emergency, The outer peripheral surface of the shaft portion is in contact with the pilot lever support portion.

Thereby, even if the engaging claw part engages with the locking gear and the mounting boss bends due to the pressing load applied to the shaft part side, the pilot lever faces the outer peripheral surface of the shaft part with a predetermined gap. Since the contact with the pilot lever supporting portion is performed, even if a large pressing load is applied by the locking gear, deformation and breakage of the mounting boss and the shaft portion can be prevented with a simple configuration. In addition, by increasing the cross-sectional shape of the pilot lever support that protrudes from the clutch, the mechanical strength of the pilot lever support can be increased, and deformation and breakage of the mounting boss and shaft can be reliably prevented. can do.

Further, the pilot lever that has received the pressing load from the locking gear supports the pressing load by contacting between the tip of the engaging claw portion and the shaft portion because the outer peripheral surface of the shaft portion contacts the pilot lever support portion. There is no need to provide a member. For this reason, it is possible to shorten the overall length of the engaging claw portion, and even if the engaging claw portion is formed in a thick shape, the mechanical strength of the pilot lever is improved and the weight is reduced. Can be achieved.

In addition, since the outer peripheral surface of the shaft portion inserted into the mounting boss normally forms a predetermined gap with the pilot lever support portion and the engagement claw portion rotates by its own weight, the pilot lever can be reduced in size. As a result, it is possible to improve the swing sensitivity of the sensor lever that activates the lock mechanism. Furthermore, since a predetermined gap is formed between the outer peripheral surface of the shaft portion inserted into the mounting boss and the pilot lever support portion, the shaft portion can be easily inserted into the mounting boss, and assembly work can be performed. Can be made more efficient.

In the seatbelt retractor of the present invention, the pilot lever support portion has a load receiving surface formed so as to be recessed in an arc shape coaxially with the mounting boss, and the load receiving surface is normally attached to the mounting boss. When the outer peripheral surface of the shaft portion inserted into the boss is opposed to the predetermined gap, forming the predetermined gap, the engaging claw portion is engaged with the locking gear and the mounting boss is bent in an emergency. The outer peripheral surface of the shaft portion may be in contact with the load receiving surface.

In such a seat belt retractor, the load receiving surface of the pilot lever support portion protruding from the clutch is formed so as to be recessed in an arc shape coaxially with the mounting boss. When the mounting boss is bent by being engaged with, the outer peripheral surface of the shaft portion is brought into contact with the load receiving surface. As a result, the pressing load received by the pilot lever can be received by the load receiving surface that is recessed in an arc shape through the outer peripheral surface of the cylindrical shaft portion, and the pressing load is distributed and received over the entire surface of the load receiving surface. Thus, deformation and breakage of the mounting boss and the shaft portion can be reliably prevented.

In addition, the pilot lever support portion can support the load distributed by the load receiving surface that is recessed in an arc shape, so that the pilot lever support portion can be reduced in size, and the size of the clutch can be reduced. Can be achieved. In addition, the load receiving surface of the pilot lever support portion normally forms a predetermined gap with the outer peripheral surface of the shaft portion inserted and inserted into the mounting boss, and thus constitutes a guide surface when the shaft portion is inserted into the mounting boss. As a result, the efficiency of the assembly work can be further improved.

Furthermore, in the seatbelt retractor of the present invention, the pilot lever support portion may be provided so as to be substantially the same height as the shaft portion fitted and inserted into the mounting boss.

In such a seatbelt retractor, the pilot lever support portion protruding from the clutch is protruded so as to be almost the same height as the shaft portion of the pilot lever inserted into the mounting boss. The pilot lever shaft portion can be brought into contact with the pilot lever support portion over almost the entire length, and deformation and breakage of the mounting boss and the shaft portion can be reliably prevented.

In order to achieve the above object, a seatbelt retractor according to the present invention includes a housing, a winding drum that is rotatably housed in the housing and winds and stores a webbing, and a ratchet that rotates integrally with the winding drum. A gear, a lock mechanism that prevents the winding drum from rotating in the webbing pull-out direction in an emergency, an inertial mass body that swings in response to an acceleration greater than a predetermined value of the vehicle, and the inertial mass body that is pushed. And a sensor lever that swings upward in the vertical direction to activate the lock mechanism, and the lock mechanism is arranged so as to be rotatable coaxially with the take-up drum, and rotates to the ratchet gear. A clutch that engages and induces a pawl that prevents rotation of the winding drum in the webbing pull-out direction, and is pivotally supported by a mounting boss that is erected on the clutch; A pilot lever that is rotated by being pressed by the moved sensor lever, and a locking gear that is integrally and coaxially attached to the winding drum and that is engaged with the pilot lever by rotation, The pilot lever includes a shaft portion into which the mounting boss is rotatably inserted, an engaging claw portion that engages with the locking gear, and an abutting portion to which the swinging sensor lever abuts and is pressed. The clutch has an extending portion that extends from the lower end edge portion so as to face the mounting boss with the shaft portion fitted into the mounting boss interposed therebetween, and the extending portion. Has an opening that allows the sensor lever that swings upward in the vertical direction to enter, and is opened so that the contact portion of the pilot lever that is rotated by its own weight in the vertical direction can enter. And the pilot lever In an emergency, when the engaging claw is engaged with the locking gear by the swinging of the sensor lever, the clutch is rotated according to the rotation of the locking gear while the contact portion is positioned in the opening. It is made to move.

In such a seatbelt retractor, the pilot lever is pivotally supported by being inserted into a mounting boss whose shaft portion is erected on the clutch. When the pilot lever rotates downward in the vertical direction due to its own weight, the contact portion of the pilot lever sandwiches the shaft portion inserted into the mounting boss from the lower end edge of the clutch, and the mounting boss It is located in the opening part formed in the extension part extended facing. Also, in the event of an emergency, even if the engaging claw of the pilot lever is engaged with the locking gear due to the swing of the sensor lever upward in the vertical direction, the contact portion of the pilot lever is still in the opening. The clutch is rotated according to the rotation of the locking gear.

As a result, the shaft portion of the pilot lever is fitted into a mounting boss standing on the clutch and pivotally supported so that the contact portion of the pilot lever extends from the lower end edge of the clutch. The pilot lever can be attached to the clutch member by attaching the locking gear to the take-up drum in a relatively non-rotatable manner and coaxially in a state where the opening is formed in the opening formed in FIG.

In addition, even when the pilot lever is pressed and rotated by the sensor lever that swings upward in the vertical direction, the contact portion with which the sensor lever abuts is formed in the extending portion that extends from the lower edge of the clutch. Since the state of entering into the opened opening is maintained, the pilot lever can be reliably prevented from coming off from the mounting boss.

Further, the pilot lever whose shaft portion is pivotally supported by the mounting boss only needs to form an engagement claw portion and a contact portion with which the sensor lever abuts, and an extended portion that extends from the lower end edge of the clutch In addition, it is only necessary to form an opening that allows the contact portion to be opened so that the sensor lever that swings upward in the vertical direction can be opened. As a result, quality control of the shape and assembly work of the lock mechanism can be simplified.

Further, in the seatbelt retractor of the present invention, the clutch has an annular rib portion erected in the vicinity of the inner peripheral surface of the locking gear and coaxially with the locking gear, and the pilot lever is When the tip of the engaging claw is brought into contact with the rib while being pivotally supported by the mounting boss, the contact is positioned above the opening in the vertical direction. You may make it do.

In such a seatbelt retractor, the engaging claw portion of the pilot lever is brought into contact with the annular rib portion of the clutch, the shaft portion is fitted into the mounting boss, and then the pilot lever is opened. The locking gear can be attached by entering the inside of the unit. This allows the pilot lever to be easily attached to the mounting boss even when the annular rib portion of the clutch is erected in the vicinity of the inner peripheral surface of the locking gear and coaxially with the locking gear. Disengagement from the mounting boss can be reliably prevented with a simple configuration.

In the seat belt retractor of the present invention, the shaft portion is formed in a cylindrical shape, and the engagement claw portion is tangentially directed from the outer peripheral surface of the shaft portion facing the locking gear to the opening portion side. The protruding portion may be provided so as to protrude from the outer peripheral surface facing the extending portion of the shaft portion toward the opening in the tangential direction.

In such a seatbelt retractor, the pilot lever protrudes toward the tangential opening so that the engaging claw portion and the abutting portion face each other from the outer peripheral surface of the cylindrical shaft portion. Since it only has to be formed, it is possible to further simplify the part shape of the pilot lever, simplify the quality control of the shape, and reduce the weight.

Further, in the seatbelt retractor of the present invention, the mounting boss is provided so that the shaft portion fitted into the mounting boss is positioned in the vicinity of the peripheral edge of the opening, and the pilot lever is When it is rotated downward in its vertical direction by its own weight, the base end portion of the contact portion comes into contact with the peripheral edge portion of the opening portion, and the tip side portion of the corresponding contact portion enters the opening portion. It may be.

In such a seatbelt retractor, when the pilot lever rotates downward in the vertical direction under its own weight, the base end portion of the contact portion contacts the peripheral portion of the opening formed in the extension portion. At the same time, a portion on the tip side of the corresponding contact portion enters the opening. Thereby, the rotation angle of the pilot lever can be regulated with a simple configuration, and the parts shapes of the clutch and the pilot lever can be further simplified.

1 is an external perspective view of a seatbelt retractor according to the present embodiment. It is the perspective view which decomposed | disassembled the seatbelt retractor for every unit. It is the perspective view which decomposed | disassembled the seatbelt retractor for every unit. It is a disassembled perspective view of a housing unit. It is a perspective view which shows the attachment state of a pawl. It is a perspective view which shows the attachment state of the pawl seen from the inner side of FIG. FIG. 6 is a cross-sectional view taken along arrow X1-X1 in FIG. 5. It is a disassembled perspective view of a winding spring unit and a lock unit. It is a disassembled perspective view of a winding spring unit and a lock unit. It is assembly sectional drawing containing the lock arm of a lock unit. It is a partially notched sectional view which shows the state which removed the mechanism cover of the lock unit. It is a principal part expanded sectional view containing the winding spring unit and lock unit of the retractor for seatbelts. It is a figure which shows attachment of a pilot lever. It is a figure which shows the attachment state of a pilot lever. It is a principal part enlarged view which shows the normal state of a pilot lever. It is a principal part enlarged view which shows the state which the pilot lever engaged with the locking gear. It is operation | movement explanatory drawing by the pulling-out acceleration of the webbing of a lock unit (before operation | movement). It is operation | movement explanatory drawing by the pulling-out acceleration of the webbing of a lock unit (at the time of an operation start). It is operation | movement explanatory drawing (at the time of transfer to a locked state) by the pulling-out acceleration of the webbing of a lock unit. It is operation | movement explanatory drawing (lock state) by the pulling-out acceleration of the webbing of a lock unit. It is operation | movement explanatory drawing by the vehicle body acceleration of a lock unit (before operation | movement). It is operation | movement explanatory drawing (at the time of an action | operation start) by the vehicle body acceleration of a lock unit. It is operation | movement explanatory drawing by the vehicle body acceleration of a lock unit (at the time of transfer to a locked state). It is operation | movement explanatory drawing (lock state) by the vehicle body acceleration of a lock unit. It is sectional drawing containing the axial center of a winding drum unit. It is a disassembled perspective view of a winding drum unit. It is the front view which looked at the winding drum from the attachment side of the ratchet gear. It is a perspective view of a ratchet gear. FIG. 26 is a cross-sectional view taken along arrow X2-X2 in FIG. It is a disassembled perspective view of a pretensioner unit. It is sectional drawing which shows the internal structure of a pretensioner unit. It is explanatory drawing which shows operation | movement of the pawl at the time of a vehicle collision. It is operation | movement explanatory drawing which pulls out a wire. It is operation | movement explanatory drawing which pulls out a wire. It is operation | movement explanatory drawing which pulls out a wire. It is operation | movement explanatory drawing which pulls out a wire.

Hereinafter, a retractor for a seat belt according to an embodiment of the present invention will be described in detail with reference to the drawings based on an embodiment.

[Schematic configuration]
First, a schematic configuration of the seatbelt retractor 1 according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is an external perspective view of a seatbelt retractor 1 according to this embodiment. 2 and 3 are exploded perspective views of the seat belt retractor 1 for each unit.
As shown in FIGS. 1 to 3, the seat belt retractor 1 is a device for winding a webbing 3 of a vehicle, and includes a housing unit 5, a winding drum unit 6, a pretensioner unit 7, and a winding unit. A spring unit 8 and a lock unit 9 are included.

Further, the lock unit 9 is fixed to one side wall portion 12 of the housing 11 constituting the housing unit 5 by each ny latch 9A and each locking hook 9B formed integrally with the mechanism cover 71 (see FIG. 8). ing. The lock unit 9 constitutes a lock mechanism 10 that stops the withdrawal of the webbing 3 in response to a sudden withdrawal of the webbing 3 or a sudden acceleration change of the vehicle, as will be described later (see FIG. 11 and the like). The take-up spring unit 8 is fixed to the outer side of the take-up drum unit 6 of the lock unit 9 in the rotational axis direction by each locking hook 8A formed integrally with a spring case 67 (see FIG. 8).

Further, the pretensioner unit 7 is arranged on the other side wall portion 13 opposite to the side wall portion 12 of the housing 11 formed in a substantially U shape in plan view, and on the outer side in the rotation axis direction of the winding drum unit 6 of the pretensioner unit 7. Are screwed by the respective screws 15 inserted therethrough. The pretensioner unit 7 includes a stopper pin 16 inserted into the side wall portion 13 from the outer side in the rotation axis direction of the winding drum unit 6 of the pretensioner unit 7, and the rotation of the winding drum unit 6 of the side wall portion 13 through the stopper pin 16. It is fixed by a push nut 18 inserted from the inside in the axial direction.

The winding drum unit 6 around which the webbing 3 is wound is rotatable between a lock unit 9 fixed to the side wall 12 of the housing unit 5 and a pretensioner unit 7 fixed to the side wall 13. Supported. The winding drum unit 6 is always urged in the winding direction of the webbing 3 by a winding spring unit 8 fixed outside the lock unit 9.

[Schematic configuration of housing unit]
Next, a schematic configuration of the housing unit 5 will be described with reference to FIGS.
FIG. 4 is an exploded perspective view of the housing unit 5. 5 and 6 are perspective views showing how the pawl is attached. 7 is a cross-sectional view taken along arrow X1-X1 in FIG.
As shown in FIGS. 2 to 4, the housing unit 5 includes a housing 11, a bracket 21, a protector 22, a pawl 23, a pawl rivet 25, a torsion coil spring 26, a sensor cover 27, and a vehicle acceleration sensor 28. And connecting

members

32 and 33 and a rivet 61.

Further, the housing 11 is formed in a substantially U shape in plan view by extending a back plate portion 31 fixed to the vehicle body and

side wall portions

12 and 13 facing each other from both side edge portions of the back plate portion 31. It is made of steel. Further, the

side wall portions

12 and 13 are connected to each other by connecting

members

32 and 33 each having a horizontally long thin plate shape that is long in the direction of the rotation axis of the winding drum unit 6. In addition, an opening is formed in the central portion of the back plate portion 31 so as to reduce the weight and limit the amount of webbing 3 accommodated.

As shown in FIGS. 4 to 7, the ratchet gear 35 of the winding drum unit 6 is inserted into the side wall portion 12 while forming a predetermined gap (for example, a gap of about 0.5 mm). A hole 36 is formed. The inner peripheral edge of the through hole 36 is configured to be recessed to the winding drum unit 6 side by a predetermined depth inward in the central axis direction, and to be opposed to the ratchet gear 35 of the winding drum unit 6.

Further, a peripheral edge facing the tip 37 (the other end) side portion 37 including the engaging

teeth

23A and 23B of the pawl 23 obliquely below (through the diagonally lower left in FIG. 4) of the through hole 36. The notch portion 38 is cut out to a depth in which the distal end portion 37 is accommodated from the portion to the outside in the turning direction of the pawl 23 (the turning direction is away from the ratchet gear 35 of the pawl 23). Is formed. A through hole 41 for rotatably mounting the pawl 23 is formed on the side of the notch 38 on the back plate 31 side. In addition, an arcuate guide portion 38 A is formed coaxially with the through hole 41 at a portion where the pawl 23 on the through hole 41 side of the cutout portion 38 abuts.

On the other hand, a portion of the pawl 23 made of steel or the like that slides in contact with the guide portion 38A has a height substantially equal to the thickness of the side wall portion 12 and has the same radius of curvature as the guide portion 38A. A stepped portion 37A that is recessed in an arc is formed. Further, a guide hole 116 (see FIGS. 9 and 10) of the clutch 85 constituting the lock unit 9 is provided at the tip of the side surface of the pawl 23 on the outer side in the rotational axis direction (the front side in FIG. 4). A guide pin 42 to be inserted is erected.

A through hole 43 through which the pawl rivet 25 is inserted is formed at the base end portion (one end portion) of the pawl 23 and is rotated from the peripheral portion of the through hole 43 to the through hole 41 of the side wall portion 12. A cylindrical boss portion 45 that can be inserted is erected at a height substantially equal to the thickness dimension of the side wall portion 12. The pawl 23 can be rotated by a pawl rivet 25 fitted into the through hole 43 from the outside of the side wall portion 12 in a state where the boss portion 45 is inserted into the through hole 41 of the side wall portion 12 from the inside of the housing 11. Fixed to. Thus, the

engagement teeth

23A, 23B of the pawl 23 and the ratchet gear portion 35A formed on the outer peripheral surface of the ratchet gear 35 are connected to the outer surface of the side wall portion 12 (the upper surface of the side wall portion 12 in FIG. 5). It is arranged so that it is almost the same plane.

Further, the head of the pawl rivet 25 is formed in a disk shape having a larger outer diameter than the through hole 41 and a predetermined thickness (for example, a thickness of about 1.5 mm). The torsion coil spring 26, which functions as an example of a return spring, is disposed so as to surround the head of the pawl rivet 25 with one winding, and one end side 26 A is attached to the guide pin 42 of the pawl 23. . The wire diameter of the torsion coil spring 26 is approximately half the height of the head of the pawl rivet 25 (for example, the wire diameter is about 0.6 mm). Accordingly, the height of one turn of the torsion coil spring 26 is set to be substantially the same as the height of the head of the pawl rivet 25.

Further, the other end side 26B of the torsion coil spring 26 passes through the side wall portion 12 side of the one end side 26A so as to be slidable on the side wall portion 12, and then the inner side direction of the side wall portion 12 (the back side of the side wall portion 12 in FIG. 5). Direction), and is inserted through a mounting hole 46 formed in the side wall portion 12. Further, the end portion of the other end side 26B is bent into a substantially U shape and is brought into contact with the inner side surface of the side wall portion 12 (the upper side surface of the side wall portion 12 in FIG. 6) to constitute a retaining portion. is doing. As a result, the pawl 23 is biased by the torsion coil spring 26 so as to rotate toward the back side of the notch 38 (in the counterclockwise direction in FIG. 5), and the tip including the

respective engagement teeth

23A and 23B. The side portion 37 is in contact with the back side of the notch 38. Accordingly, the pawl 23 is urged to rotate in a direction away from the ratchet gear 35 by the torsion coil spring 26.

Further, as shown in FIGS. 2 to 4, below the through hole 36 of the side wall portion 12 (downward in FIG. 4), below the central axis of the through hole 36 (downward in FIG. 4). To the back plate portion 31 side, a substantially rectangular opening 47 is formed. In addition, a shallow substantially box-shaped sensor cover 27 having a substantially rectangular cross section substantially the same as the opening 47 is fitted into the opening 47 from the outside (the front side in FIG. 4). The resin-made sensor cover 27 has a flange formed on the opening-side peripheral edge abutting on the outer peripheral edge of the opening 47 (the front-side peripheral edge in FIG. 4), and the sensor cover. 4, a pair of locking claws 27A projecting from both end faces in the up-down direction are fitted into the back side of both end parts in the up-down direction in FIG.

Further, the vehicle acceleration sensor 28 includes a resin-made sensor holder 51 having a substantially box shape opened to the upper side in the vertical direction (upper side in FIG. 4) and having a mortar-shaped mounting portion formed on the bottom surface portion, Inertial mass 52 formed in a spherical body of metal such as steel and movably mounted on the mounting portion, and placed on the upper side in the vertical direction of inertial mass 52 and opposite to pawl 23 From the sensor lever 53 made of resin, the end edge portion (the right end edge portion in FIG. 4) is supported by the sensor holder 51 so as to be swingable vertically (in the vertical direction in FIG. 4). It is configured.

Then, the vehicle acceleration sensor 28 is fitted into the sensor cover 27, and a pair of locking claws 51 A (one engagement in FIG. 4) provided on both side surfaces facing both side walls in the sensor cover 27 of the sensor holder 51. The vehicle acceleration sensor 28 is attached to the housing 11 via the sensor cover 27 by inserting and locking the pawl 51A into each locking hole 27B of the sensor cover 27.

Further, the side wall portion 12 has three corners, that is, both corners of an upper edge portion (upper edge portion in FIG. 4) and a lower portion of the through hole 36 (downward direction in FIG. 4). Each mounting hole 55 into which each ny latch 9A of the lock unit 9 is fitted and attached is formed. In addition, each locking piece to which each locking hook 9 B of the lock unit 9 is elastically locked is located at the center of the left and right side edges of the side wall 12 (the vertical center in FIG. 4). 56 is formed so as to project perpendicularly to the rotation axis of the winding drum unit 6.

Further, a through hole 57 through which the winding drum unit 6 is inserted is formed in the side wall portion 13 at the center portion. Further, the side wall portion 13 includes a substantially lower end edge portion (lower end edge portion in FIG. 2), a corner portion on the connecting member 33 side, and an upper end edge portion (upper end edge portion in FIG. 2). The screw holes 58 into which the screws 15 are screwed are formed by burring in the direction of the pretensioner unit 7 at the corners on the back plate portion 31 side. Further, a through hole 59 through which the stopper pin 16 is inserted is formed in the side wall portion 13 at a corner portion on the connecting member 32 side of the upper end edge portion (the upper end edge portion in FIG. 2).

Moreover, the bracket 21 attached to each upper end edge (the upper end edge in FIG. 2) of the back plate 31 by each rivet 61 is formed of a steel material or the like, and the upper end edge of the back plate 31 A laterally long through hole 62 extending in the width direction of the back plate portion 31 from which the webbing 3 is pulled out is formed in an extending portion extending in the direction of the connecting member 32 at a substantially right angle from the side, and is formed of a synthetic resin such as nylon. A horizontally long frame-shaped protector 22 is fitted. Further, a bolt insertion hole 63 through which a bolt is inserted when being attached to a fastening piece (not shown) of the vehicle is formed in the lower end portion (the lower end portion in FIG. 2) of the back plate portion 31. .

[Schematic configuration of winding spring unit]
Next, a schematic configuration of the winding spring unit 8 will be described with reference to FIGS. 2, 3, 8, 9, and 12.
8 and 9 are exploded perspective views of the take-up spring unit 8 and the lock unit 9. FIG. 12 is an enlarged cross-sectional view of a main part including the winding spring unit 8 and the lock unit 9 of the seat belt retractor 1.

2, 3, 8, 9, and 12, the winding spring unit 8 includes a spiral spring 65 and an outer end 65 A of the spiral spring 65 erected from the bottom surface of the inner peripheral edge. The spring case 67 is fixed to the rib 66 and accommodates the spiral spring 65, and the spring shaft 68 is connected to the inner end 65B of the spiral spring 65 and the spring force is biased. Further, the spring case 67 is formed with a groove portion 67A having a predetermined depth (for example, a depth of about 2.5 mm) over the entire circumference at the edge portion on the mechanism cover 71 side constituting the lock unit 9. ing.

Then, the elastic locking pieces 72 projecting from the three locations on the outer periphery of the mechanism cover 71 toward the take-up spring unit 8 are inserted into the locking hooks 8 A provided at the three locations on the outer periphery of the spring case 67. Thus, the winding spring unit 8 is fixed in contact with the outer side in the rotation axis direction of the winding drum unit 6 of the lock unit 9 by being elastically locked. Further, a substantially ring-shaped rib portion 71A erected at a predetermined height (for example, a height of about 2 mm) along the outer peripheral edge portion of the mechanism cover 71 in the rotation axis direction of the winding drum unit 6 is a spring case. The groove 67A is inserted into the groove 67A to prevent dust or dust from entering the spring case 67.

Further, the spring shaft 68 has a pin 69 erected at a substantially central position of the bottom surface portion of the spring case 67 inserted into the through hole 68 A of the bottom surface portion, and the bottom surface portion side abuts rotatably on the peripheral edge portion of the pin 69. Has been. Further, the end portion of the spring shaft 68 on the lock unit 9 side is rotatably contacted with a peripheral portion on the back surface side of the through hole 73 formed in the substantially central portion of the mechanism cover 71.

In addition, a spline is formed on the outer peripheral surface of the ratchet gear 35 on the outer side in the rotational axis direction (the left side surface in FIG. 3), and the tip is formed in a substantially rectangular cross section. A shaft portion 76 is erected. Then, the tip end portion of the shaft portion 76 formed in a substantially rectangular cross section is fitted into the cylindrical hole 68B formed in the rectangular cross section of the spring shaft 68 from the through hole 73 of the mechanism cover 71, and the spring shaft 68. Are connected so as not to rotate relative to each other (see FIG. 12). As a result, the shaft portion 76 is coupled to the spiral spring 65 via the spring shaft 68, and the biasing force of the spiral spring 65 constantly biases the winding drum unit 6 to rotate in the winding direction of the webbing 3. Has been.

[Schematic configuration of locking mechanism]
Next, a schematic configuration of the lock unit 9 constituting the lock mechanism 10 that stops the pull-out of the webbing 3 in response to a rapid pull-out of the webbing 3 or a rapid acceleration of the vehicle will be described with reference to FIGS. To do. FIG. 10 is an assembly sectional view including the lock arm of the lock unit 9. FIG. 11 is a partially cutaway sectional view showing a state in which the mechanism cover of the lock unit 9 is removed. FIG. 13 is a diagram showing attachment of the pilot lever. FIG. 14 is a view showing a state where the pilot lever is attached. FIG. 15 is an enlarged view of a main part showing a normal state of the pilot lever. FIG. 16 is an enlarged view of a main part showing a state where the pilot lever is engaged with the locking gear.

8 to 12, the lock unit 9 includes a mechanism cover 71, a locking gear 81, a lock arm 82, a sensor spring 83, a clutch 85, and a pilot lever 86. Of the members constituting the lock unit 9, the members excluding the sensor spring 83 are formed of synthetic resin, and the friction coefficient between the members when they are in contact with each other is small.

The mechanism cover 71 is formed with a substantially box-shaped mechanism housing portion 87 having a substantially circular bottom surface that is open on the side wall 12 side of the housing 11, and is configured to house the locking gear 81, the clutch 85, and the like. Yes. Further, the mechanism cover 71 is formed in a concave shape having a substantially square cross section at a corner portion (the lower left corner portion in FIG. 9) facing the vehicle acceleration sensor 28 attached to the housing 11 via the sensor cover 27. The sensor housing portion 88 is provided.

When the mechanism cover 71 is attached to the side wall portion 12 by the ny latches 9A and the locking hooks 9B, the sensor holder 51 of the vehicle acceleration sensor 28 is fitted into the sensor housing portion 88, and the sensor lever 53 is moved in the vertical direction. It is configured to be swingable up and down (in the vertical direction in FIG. 9). Further, the mechanism housing portion 87 and the sensor housing portion 88 are established so as to communicate with the lower end portion substantially central portion (in FIG. 9, the lower end portion substantially central portion) of the mechanism cover portion 87 of the mechanism cover 71. Opening 89 is formed.

The opening 89 is formed so that the front end of the lock claw 53A projecting upward from the front edge of the sensor lever 53 of the vehicle acceleration sensor 28 (upward in FIG. 9) is vertically up and down ( In FIG. 9, the front end of the lock claw 53 A is positioned in the vicinity of the receiving plate portion 122 (see FIG. 11) of the pilot lever 86. As will be described later, when the inertial mass body 52 is moved by acceleration exceeding a predetermined value and the sensor lever 53 is rotated upward in the vertical direction, the lock claw 53A is connected to the pilot lever 86 via the opening 89. The pilot lever 86 is configured to be pivoted upward in the vertical direction by contacting the receiving plate portion 122 (see FIG. 22).

Further, a cylindrical support boss 91 is erected on the substantially circular bottom surface portion of the mechanism housing portion 87 from the peripheral edge portion of the through hole 73 formed in the center portion. The outer periphery of the tip end portion of the support boss 91 on the side of the locking gear 81 is formed with a tapered chamfered portion 91A inclined at a predetermined angle (for example, an inclination angle of about 30 °) toward the tip end over the entire circumference. ing. The support boss 91 is fitted with a cylindrical fixed boss 93 erected so as to penetrate from the front side to the back side at the center of the disc-shaped bottom surface 92 of the locking gear 81. Supported for dynamic rotation.

The locking gear 81 is erected in an annular shape from the entire circumference of the disk-shaped bottom surface 92 to the clutch 85 side, and locking gear teeth 81A that engage with the pilot lever 86 are formed on the outer periphery. The locking gear teeth 81A are formed so as to engage with the engaging claws 86A of the pilot lever 86 only when the locking gear 81 rotates in the webbing pull-out direction (see FIG. 16).

Further, as shown in FIGS. 8 and 12, the support boss of the mechanism cover 71 is provided around the entire periphery of the base end portion of the fixed boss 93 protruding from the back side facing the mechanism cover 71 of the locking gear 81. An insertion groove 95 into which 91 is inserted over almost the entire height is formed coaxially with the fixed boss 93. The inner peripheral wall portion on the radially outer side of the insertion groove 95 is inclined outward in the radial direction at an angle larger than the inclination angle of the tip end portion of the support boss 91 (for example, an inclination angle of about 45 °).

Further, the height of the fixed boss 93 protruding from the back side facing the mechanism cover 71 of the locking gear 81 is substantially equal to the distance from the tip of the support boss 91 of the mechanism cover 71 to the back side of the mechanism cover 71. Has been. As a result, the fixed boss 93 protruding from the back side of the locking gear 81 is inserted into the support boss 91 of the mechanism cover 71, and the tip of the support boss 91 is brought into contact with the insertion groove 95. A fixed boss 93 protruding from the back side is attached to and coaxially supported by the support boss 91 over almost the entire height.

Also, a spline groove into which a spline 76A (see FIG. 3) formed on the outer peripheral surface of the shaft portion 76 of the ratchet gear 35 is fitted is formed on the inner peripheral surface of the fixed boss 93 of the locking gear 81. Thus, by fitting the shaft portion 76 of the ratchet gear 35 into the fixed boss 93 of the locking gear 81, the ratchet gear 35 and the locking gear 81 of the winding drum unit 6 are press-fitted and fixed coaxially so as not to be relatively rotatable. The shaft portion 76 of the ratchet gear 35 is pivotally supported by the support boss 91 of the mechanism cover 71 via the fixed boss 93.

As shown in FIGS. 8 to 12, a cylindrical support boss 96 adjacent to the fixed boss 93 is provided at a lower height than the locking gear teeth 81A on the surface of the bottom surface portion 92 of the locking gear 81 on the clutch 85 side. It is erected. The lock arm 82 made of synthetic resin formed in a substantially arcuate shape so as to surround the fixed boss 93 is supported by a pivot shaft 97 erected on the end edge on the side of the fixed boss 93 in the substantially central portion in the longitudinal direction. The boss 96 is rotatably inserted and pivotally supported.

Further, the lock arm 82 is provided with an elastic locking piece 98 having an inverted L-shaped cross section on the side of the pivot shaft 97 and standing on the bottom surface 92 side of the locking gear 81. The elastic locking piece 98 is inserted into a window 99 having a stepped portion in a substantially fan shape formed at the base end portion of the support boss 96 of the locking gear 81 and is elastic so as to be rotatable around the axis of the support boss 96. Is locked.

Further, as shown in FIGS. 10 and 11, the locking gear 81 includes a spring support pin 101 into which one end side of the sensor spring 83 is fitted into a rib portion extending radially outward from the outer peripheral surface of the fixed boss 93. The webbing is extended in the direction perpendicular to the axis of the fixed boss 93. In addition, a spring support pin 102 into which the other end side of the sensor spring 83 is fitted is erected on the side wall of the lock arm 82 facing the spring support pin 101.

Therefore, as shown in FIGS. 10 and 11, the lock arm 82 moves toward the webbing pull-out direction side with respect to the axis of the fixed boss 93 by fitting both ends of the sensor spring 83 into the spring support pins 101 and 102 ( In FIG. 10, it is biased with a predetermined load so as to rotate (in the direction of arrow 103). The lock arm 82 is in contact with a stopper 107 erected on the bottom surface 92 of the locking gear 81 at the end edge of the clutch 85 on the side of the engaging claw 105 that engages with the clutch gear 106.

On the other hand, as will be described later, the lock arm 82 is rotated in the webbing take-up direction (in the opposite direction to the arrow 103 in FIG. 10) against the urging force of the sensor spring 83 and engaged with the clutch gear 106. In this case, the end edge portion of the engagement claw 105 opposite to the engagement portion is configured to be able to abut on the spindle-shaped detent 108 having a cross-sectional spindle shape standing on the bottom surface portion 92 of the locking gear 81. (See FIG. 18).

Further, as shown in FIGS. 8 to 12, the fixed boss 93 of the locking gear 81 is formed with a stepped portion 93A having a thin outer diameter at the tip of the clutch 85 side. The height dimension in the axial direction of the stepped portion 93A is formed to be slightly larger than the thickness dimension of the substantially disk-shaped plate portion 111 of the clutch 85. A through-hole 112 formed in the central portion of the plate portion 111 of the clutch 85 is rotatably fitted into the step portion 93A of the fixed boss 93, and the clutch 85 is fixed to the mechanical housing portion 87 of the mechanism cover 71. It is accommodated so as to be rotatable within the rotation range.

12, the stepped portion 93A of the fixed boss 93 of the locking gear 81 fitted in the through hole 112 of the clutch 85 is brought into contact with the proximal end portion of the shaft portion 76 of the ratchet gear 35. Thus, the ratchet gear 35 is pivotally supported on the support boss 91 of the mechanism cover 71 via the fixed boss 93 in a state where the stepped portion 93A of the fixed boss 93 is in contact with the base end portion of the shaft portion 76. The shaft is rotatably supported integrally with the locking gear 81.

Further, as shown in FIGS. 8 to 12, on the mechanism cover 71 side of the clutch 85, an inner periphery of an annular rib formed with locking gear teeth 81A of the locking gear 81 coaxially with the through hole 112 is provided. An annular rib 113 having an outer diameter slightly smaller than the diameter is provided upright. A clutch gear 106 is formed on the inner peripheral surface of the rib 113 so that the engagement claw 105 of the lock arm 82 is engaged (see FIG. 18). As will be described later, the clutch gear 106 is formed to engage with the engaging claw 105 of the lock arm 82 only when the locking gear 81 rotates in the webbing pull-out direction with respect to the axis of the through hole 112. (See FIG. 18).

Further, a substantially annular outer rib portion 115 is erected on the outer peripheral portion of the plate portion 111 of the clutch 85 so as to surround the rib portion 113. A corner portion (the lower left corner portion in FIG. 10) of the outer rib portion 115 facing the pawl 23 is extended outward in the radial direction, and is formed on the side surface of the tip portion including the engaging teeth 23 A of the pawl 23. A substantially elongated guide hole 116 is formed in which the upright guide pin 42 is loosely fitted from the ratchet gear 35 side.

As shown in FIG. 11, the guide hole 116 is formed in a long groove shape substantially parallel to the webbing pull-out direction (vertical direction in FIG. 11) at the corner of the outer rib portion 115 facing the pawl 23. ing. As a result, as described later, when the clutch 85 is rotated in the webbing pull-out direction (in the direction of arrow 103 in FIG. 10), the guide pin 42 is moved along the guide hole 116 and the pawl 23 is moved. The engaging

teeth

23A and 23B are rotated so as to approach the ratchet gear portion 35A of the ratchet gear 35 (see FIGS. 18 to 20).

The pawl 23 is urged to rotate away from the ratchet gear 35 by the urging force of the torsion coil spring 26, and the clutch 85 is urged by the guide pin 42 of the pawl 23 that is loosely fitted in the guide hole 116. ing. Due to this urging force, the clutch 85 is the end edge portion at the position farthest away from the ratchet gear 35 in the rotational radius direction of the clutch 85 in the guide hole 116 (the lower end edge portion of the guide hole 116 in FIG. 10). ) Is biased so as to be in a rotational posture in a state where the guide pin 42 of the pawl 23 abuts, so that the webbing is pulled out in a direction opposite to the drawing direction. At the same time, the pawl 23 is normally an end edge portion at a position farthest away from the ratchet gear 35 in the radial direction of the clutch 85 in the guide hole 116 (the lower end edge portion of the guide hole 116 in FIG. 10). ), The guide pin 42 of the pawl 23 abuts and the rotation of the pawl 23 is restricted.

Further, as shown in FIGS. 8 to 12, the lower end edge portion (the lower end edge portion in FIG. 8) of the outer rib portion 115 of the clutch 85 is located on the sensor housing portion 88 from the position near the guide hole 116. A plate-like extending portion 117 extending to the vicinity of the bottom surface portion of the mechanism accommodating portion 87 in the rotational axis direction of the winding drum unit 6 is formed at a portion facing upward (in FIG. 8, the upward direction). ing. A thin columnar mounting boss 121 fitted into the cylindrical shaft portion 118 of the pilot lever 86 is extended at a position in the vicinity of the edge portion on the opposite side to the guide hole 116 of the extension portion 117. The portion 117 is erected on the mechanism cover 71 side at substantially the same height as the height in the extending direction.

Here, the pilot lever 86 includes a cylindrical shaft portion 118, an engaging claw portion 86A, a thin plate-like receiving plate portion 122, and a thin plate-like connecting plate portion 123. The axial length of the shaft portion 118 is formed to be approximately the same as the height of the extending portion 117 in the extending direction. Further, the engaging claw portion 86A has a predetermined width and thickness of about half the outer diameter of the shaft portion 118 from the outer peripheral surface facing the rib portion 113 of the shaft portion 118 to the tangential guide hole 116 side. The length is protruding.

Further, the receiving plate portion 122 has a width dimension substantially the same as the width dimension of the engaging claw portion 86A from the axial central portion of the outer peripheral surface facing the extending portion 117 of the shaft portion 118 so as to face the engaging claw portion 86A. And projecting toward the tangential guide hole 116, and the distal end is bent obliquely toward the distal end of the engaging claw 86. Further, the connecting plate portion 123 is formed so as to connect the engaging claw portion 86 A and the front end portion of the receiving plate portion 122.

Further, as shown in FIGS. 8, 13, and 14, the pilot lever support block 125 is the same as the height of the extending portion 117 in the extending direction at the end edge portion facing the mounting boss 121 of the extending portion 117. It protrudes toward the mechanism cover 71 at a height. On the inner side of the pilot lever support block 125 facing the mounting boss 121, it extends slightly obliquely from the end edge of the extending portion 117 toward the mounting boss 121, and is coaxial with the mounting boss 121 and pilot. A load receiving surface 126 formed on a smooth curved surface having a substantially semicircular shape in front view with a radius of curvature that is slightly larger (for example, about 0.1 mm larger) than the radius of the outer peripheral surface of the shaft portion 118 of the lever 86 is provided. Yes.

Further, an opening 127 having a rectangular shape in a plan view is formed at the edge of the extending portion 117 on the pilot lever support block 125 side from the substantially lower position of the mounting boss 121 to the guide hole 116 side. As shown in FIGS. 10, 13, and 14, the opening 127 is formed so that the pilot lever 86 with the shaft 118 inserted into the mounting boss 121 is vertically lowered by its own weight (in the downward direction in FIG. 14). The receiving plate portion 122 and the connecting plate portion 123 are formed so as to be able to enter into the opening 127.

Further, as shown in FIGS. 9 and 11, the opening 127 of the clutch 85 is provided so as to face the opening 89 of the mechanism cover 71, and the vehicle acceleration sensor 28 disposed in the sensor housing portion 88. When the sensor lever 53 is rotated upward in the vertical direction, the lock claw 53A is configured to be able to enter.

As shown in FIG. 13, when the shaft 118 of the pilot lever 86 is fitted into the mounting boss 121 of the clutch 85 and the tip of the engaging claw 86A is brought into contact with the outer peripheral surface of the rib 113. A narrow gap 124 (for example, a gap of about 1 mm) is formed between the receiving plate portion 122 and the extending portion 117.

Thus, the shaft portion 118 of the pilot lever 86 can be inserted until it comes into contact with the plate portion 111 of the clutch 85, and the pilot lever 86 can be rotatably attached to the mounting boss 121. Further, since a predetermined gap 128 (for example, a gap of about 0.1 mm) is formed between the outer peripheral surface of the shaft portion 118 and the load receiving surface 126 of the pilot lever support block 125, the pilot lever 86 rotates smoothly up and down in the vertical direction.

After that, as shown in FIG. 14, when the pilot lever 86 is rotated vertically downward (downward in FIG. 14) by its own weight, the receiving plate portion 122 is moved to the pilot of the opening 127. Abutting on the end edge portion on the lever support block 125 side, the rotation angle to the lower side in the vertical direction (the lower direction in FIG. 14) is restricted. Further, the lower end portion in the vertical direction of the receiving plate portion 122 is positioned at the substantially lower end portion in the vertical direction of the opening 127, and the engaging claw portion 86A is substantially parallel to the tangential direction of the rib portion 113 of the clutch 85. It becomes. That is, a gap 129 into which the locking gear tooth 81A of the locking gear 81 can be inserted is formed between the outer peripheral surface of the rib portion 113 of the clutch 85 and the engaging claw portion 86A.

Subsequently, as shown in FIG. 15, the fixing boss 93 of the locking gear 81 is inserted into the through hole 112 of the clutch 85 in a state where the pilot lever 86 is rotated downward in the vertical direction (downward in FIG. 15). By inserting the step portion 93A, the locking gear teeth 81A are rotatably disposed between the outer peripheral surface of the rib portion 113 of the clutch 85 and the engaging claw portion 86A.

Therefore, even if the pilot lever 86 is rotated upward in the vertical direction (upward in FIG. 15), the engaging claw portion 86A abuts against the locking gear teeth 81A. Is located in the opening 127. Thereby, by attaching the locking gear 81 to the clutch 85, the pilot lever 86 can be prevented from coming off from the attachment boss 121.

Further, as shown in FIG. 16, the sensor lever 53 is rotated upward in the vertical direction (upward in FIG. 16), and the engagement claw portion 86A is engaged with the locking gear tooth 81A by the lock claw 53A. In this state, when the locking gear 81 rotates in the webbing pull-out direction (in the direction of arrow 131) (see FIG. 22), the engagement claw portion 86A has a mounting boss 121 side direction (in the direction of arrow 132). There is a large load.

When the mounting boss 121 is bent due to a load applied to the engaging claw portion 86A, the outer peripheral surface of the shaft portion 118 comes into contact with the load receiving surface 126 of the pilot lever support block 125. It can be supported by the load receiving surface 126 via the shaft portion 118. Thereby, even if the pilot lever 86 and the mounting boss 121 are made small, the deformation and breakage of the shaft portion 118 and the mounting boss 121 that support the pressing load can be prevented.

Next, the operation of the lock mechanism 10 will be described with reference to FIGS. In each figure, the pulling-out direction of the webbing 3 is an arrow 135 direction. In each figure, the counterclockwise rotation direction is the rotation direction (webbing pull-out direction) of the winding drum unit 6 when the webbing 3 is pulled out. Further, for the explanation of the operation of the lock mechanism 10, a part of the drawing is cut out and displayed as necessary.

Here, the locking mechanism 10 is a “webbing sensitive locking mechanism” that operates when the webbing 3 is suddenly pulled out, and a “vehicle body sensitive type” that operates in response to an acceleration caused by a vehicle shake or inclination. It operates as two types of lock mechanisms, “lock mechanism”. The operation of the pawl 23 is common to both the “webbing sensitive lock mechanism” and the “vehicle body sensitive lock mechanism”. For this reason, in FIGS. 17 to 24, the portion showing the relationship between the pawl 23 and the ratchet gear 35 is shown as a state in which a part thereof is cut away.

[Description of webbing-sensitive locking mechanism]
First, the operation of the “webbing sensitive lock mechanism” will be described with reference to FIGS. 17 to 20 are explanatory views for explaining the operation of the “webbing sensitive lock mechanism”. In the “webbing sensitive lock mechanism”, in addition to the portion indicating the relationship between the pawl 23 and the ratchet gear 35, the portion indicating the relationship between the lock arm 82 and the clutch gear 106 and the portion indicating the movement of the sensor spring 83 are cut off. Missing shows.

As shown in FIGS. 17 and 18, since the lock arm 82 is pivotally supported by the support boss 96 of the locking gear 81 so that the pivot shaft 97 can rotate, the pull-out acceleration of the webbing 3 is a predetermined acceleration (for example, about 2). In the case of exceeding 1 G≈9.8 m / s 2), the lock arm 82 is turned against the rotation of the locking gear 81 in the webbing pull-out direction (in the direction of arrow 136). Inertia lag occurs.

For this reason, the lock arm 82 that has been in contact with the stopper 107 rotates clockwise around the pivot shaft 97 with respect to the locking gear 81 in order to maintain the initial position against the biasing force of the sensor spring 83. It is rotated until it comes into contact with the detent 108. Therefore, the engagement claw 105 of the lock arm 82 is rotated radially outward with respect to the rotation shaft of the locking gear 81 and engaged with the clutch gear 106 of the clutch 85.

As shown in FIGS. 18 and 19, when the webbing 3 is continuously pulled out beyond a predetermined acceleration, the locking gear 81 is further rotated in the webbing pull-out direction. 105 is engaged with the clutch gear 106 and is rotated in the webbing pull-out direction (in the direction of arrow 136) by the rotation stopper 108. Accordingly, since the clutch gear 106 is rotated in the webbing pull-out direction by the lock arm 82, the clutch 85 is caused by the guide pin 42 of the pawl 23 that is urged to rotate away from the ratchet gear 35 by the torsion coil spring 26. Against the urging force, the locking gear 81 is rotated in the webbing pull-out direction around the axis of the fixed boss 93.

As a result, the guide pin 42 of the pawl 23 is guided by the guide hole 116 of the clutch 85 as the clutch 85 rotates in the webbing pull-out direction, so that the pawl 23 resists the biasing force of the torsion coil spring 26. Then, it is rotated toward the ratchet gear 35 (in the direction of arrow 137).

Then, as shown in FIG. 20, when the webbing 3 is further pulled out beyond the predetermined acceleration, the clutch 85 is urged to rotate away from the ratchet gear 35 by the torsion coil spring 26. The webbing is further rotated in the webbing pull-out direction (in the direction of arrow 136) against the urging force of the 23 guide pins 42. Therefore, the guide pin 42 of the pawl 23 is further guided by the guide hole 116 of the clutch 85, and the pawl 23 is engaged with the ratchet gear portion 35 A of the ratchet gear 35 against the urging force of the torsion coil spring 26. Is done. Thereby, the rotation of the winding drum unit 6 is locked and the drawer of the webbing 3 is locked.

Thereafter, when the pulling force applied to the webbing 3 is relaxed, the winding drum unit 6 is moved in the webbing winding direction (the direction opposite to the arrow 136) by the urging force of the winding spring unit 8. To be rotated. Thereby, the engagement between the ratchet gear 35 and the pawl 23 is released, and the pawl 23 is rotated in a direction away from the ratchet gear 35 by the torsion coil spring 26.

Therefore, when the pulling force applied to the webbing 3 is relaxed and returned to normal, the pawl 23 is separated from the ratchet gear 35 by the rotational biasing force of the torsion coil spring 26, and the winding drum unit 6 by the pawl 23 is separated. The locked state is released (see FIG. 17). Further, as the guide pin 42 of the pawl 23 moves in the reverse direction in the guide hole 116 as the pawl 23 is rotated by the urging force of the torsion coil spring 26, the clutch 85 moves in the webbing winding direction (clockwise in FIG. 20). The guide pin 42 is turned to the end edge portion (the lower end edge portion of the guide hole 116 in FIG. 17) located at the position farthest from the ratchet gear 35 of the guide hole 116. It returns to the normal rotation posture in contact (see FIG. 17).

Further, the lock arm 82 is rotated in the webbing pull-out direction (in the counterclockwise direction in FIG. 20) by the urging force of the sensor spring 83, is brought into contact with the stopper 107, and the engagement claw of the lock arm 82 is engaged. The engagement between the clutch 105 and the clutch gear 106 is released (see FIG. 17).

[Explanation of body-sensitive locking mechanism]
Next, the operation of the “vehicle body sensitive locking mechanism” will be described with reference to FIGS. 21 to 24 are explanatory views for explaining the operation of the “vehicle body sensitive locking mechanism”. In the “vehicle body sensitive locking mechanism”, in addition to the portion indicating the relationship between the pawl 23 and the ratchet gear 35, the portions of the sensor holder 51 and the sensor lever 53 of the vehicle acceleration sensor 28 are notched.

As shown in FIGS. 21 and 22, since the spherical inertia mass body 52 of the vehicle acceleration sensor 28 is placed on the mortar-shaped bottom surface portion of the sensor holder 51, acceleration due to shaking or tilting of the vehicle body is caused. When a predetermined acceleration (for example, about 2.0 G) is exceeded, the bottom surface of the sensor holder 51 is moved to rotate the sensor lever 53 upward in the vertical direction.

For this reason, the lock claw 53A of the sensor lever 53 enters the opening 127 provided in the extending portion 117 of the clutch 85, and is received by the pilot lever 86 that is rotatably attached to the attachment boss 121 of the clutch 85. The pilot lever 86 is brought into contact with the plate portion 122 and rotated upward in the vertical direction. Accordingly, the pilot lever 86 is rotated in the clockwise direction (in the direction of the arrow 138) around the axis of the mounting boss 121, and the distal end portion of the engaging claw portion 86A of the pilot lever 86 is the outer peripheral portion of the locking gear 81. Is engaged with a locking gear tooth 81A.

22 and FIG. 23, when the webbing 3 is pulled out with the pilot lever 86 engaged with the locking gear teeth 81A of the locking gear 81, the locking gear 81 is pulled in the webbing pull-out direction ( In the direction of arrow 141). The rotation of the locking gear 81 in the webbing pull-out direction is transmitted to the clutch 85 via the pilot lever 86, the mounting boss 121 and the pilot lever support block 125.

Therefore, as the locking gear 81 rotates in the webbing pull-out direction, the clutch 85 is urged by the guide pin 42 of the pawl 23 that is urged to rotate away from the ratchet gear 35 by the torsion coil spring 26. Against this, it is rotated in the webbing pull-out direction around the axis of the fixed boss 93 of the locking gear 81. Thus, as the clutch 85 rotates in the webbing pull-out direction, the guide pin 42 of the pawl 23 is guided to the guide hole 116 of the clutch 85, so that the pawl 23 is rotated to the ratchet gear 35 side. (In the direction of arrow 142).

As shown in FIG. 24, when the webbing 3 is further pulled out, the clutch 85 is urged to rotate away from the ratchet gear 35 by the torsion coil spring 26. The webbing is further rotated in the webbing pull-out direction (in the direction of arrow 141) against the urging force of 42. For this reason, the guide pin 42 of the pawl 23 is guided by the guide hole 116 of the clutch 85, and the pawl 23 is engaged with the ratchet gear portion 35 A of the ratchet gear 35. Thereby, the rotation of the winding drum unit 6 is locked and the drawer of the webbing 3 is locked.

Thereafter, when the pulling force applied to the webbing 3 is loosened, the winding drum unit 6 is moved in the webbing winding direction (the direction opposite to the arrow 141) by the urging force of the winding spring unit 8. To be rotated. Thereby, the engagement between the ratchet gear 35 and the pawl 23 is released, and the pawl 23 is rotated in a direction away from the ratchet gear 35 by the torsion coil spring 26. Further, the engagement between the pilot lever 86 and the locking gear teeth 81A is released, and the pilot lever 86 is rotated inwardly by the own weight of the opening 127.

Accordingly, when the pulling force applied to the webbing 3 is relaxed and returned to the normal time, and the inertial mass body 52 of the vehicle acceleration sensor 28 returns to the normal time at the center of the mortar-shaped bottom surface of the sensor holder 51. The pawl 23 is separated from the ratchet gear 35 by the rotational biasing force of the torsion coil spring 26, and the locked state of the winding drum unit 6 by the pawl 23 is released (see FIG. 21).

Further, as the guide pin 42 of the pawl 23 moves in the reverse direction in the guide hole 116 as the pawl 23 is rotated by the urging force of the torsion coil spring 26, the clutch 85 moves in the webbing winding direction (clockwise in FIG. 24). The guide pin 42 is moved to the end edge portion (the lower end edge portion of the guide hole 116 in FIG. 21) at the position farthest from the ratchet gear 35 of the guide hole 116. It returns to the normal rotation posture in contact (see FIG. 21). Further, the pilot lever 86 is rotated to the vehicle acceleration sensor 28 side by its own weight, and the receiving plate portion 122 enters the opening 127 and is positioned in the vicinity of the lock claw 53A of the sensor lever 53 (see FIG. 21).

[Schematic configuration of winding drum unit]
Next, a schematic configuration of the winding drum unit 6 will be described with reference to FIGS. 2, 3, 25 to 29. FIG. FIG. 25 is a cross-sectional view including the axis of the winding drum unit 6. FIG. 26 is an exploded perspective view of the winding drum unit 6. FIG. 27 is a front view of the winding drum 151 as viewed from the side where the ratchet gear 35 is attached. FIG. 28 is a perspective view of the ratchet gear 35. 29 is a cross-sectional view taken along arrow X2-X2 in FIG.
As shown in FIGS. 25 and 26, the winding drum unit 6 includes a winding drum 151, a torsion bar 152, a wire 153, and a ratchet gear 35.

As shown in FIGS. 2, 3, 25, and 26, the winding drum 151 is formed by aluminum die casting, zinc die casting, or the like, and is formed in a substantially cylindrical shape in which the end surface portion on the pretensioner unit 7 side is closed. Has been. Further, an end edge portion on the pretensioner unit 7 side in the axial direction of the winding drum 151 extends in the radial direction from the outer peripheral portion, and further in a substantially right-angled outward direction (the left side direction in FIG. 25). An extended flange portion 155 is formed. In addition, an internal gear to which each clutch pawl 202 (see FIG. 30) is engaged and the rotation of the pinion gear 185 (see FIG. 30) is transmitted to the inner peripheral surface of the flange portion 155 in the event of a vehicle collision, as will be described later. 156 is formed.

Further, a cylindrical boss 157 is erected at the center position of the end surface of the winding drum 151 on the pretensioner unit 7 side. The boss 157 is fitted into a bearing 205 (see FIG. 30) formed of a synthetic resin material such as polyacetal described later, and a base end portion of the boss 157 is brought into contact with the bearing 205. Thereby, the one end side of the winding drum unit 6 is rotatably supported by the boss portion 185D (see FIG. 30) of the pinion gear 185 constituting the pretensioner unit 7 via the bearing 205. Accordingly, the take-up drum unit 6 is rotatably supported by the pretensioner unit 7 and the lock unit 9 while preventing backlash in the rotation axis direction.

Further, on the inner side of the winding drum 151, there is formed a shaft hole 151A in which a draft angle is formed so as to become gradually narrower along the central axis. Further, as shown in FIGS. 25 and 27, five projecting portions 158A to 158E having a substantially trapezoidal cross section are formed at constant intervals in the circumferential direction on the inner peripheral surface of the flange portion 155 side end portion in the shaft hole 151A. And projecting in a rib shape inward in the radial direction. The torsion bar 152 includes a shaft portion 152C formed of a steel material and having a circular cross section, and

splines

152A and 152B formed at both ends of the shaft portion 152C.

Further, the projecting portions 158A to 158E are provided so as to be fitted between the projecting portions of the spline 152A formed at one end portion of the torsion bar 152 formed of a steel material or the like. As a result, as shown in FIGS. 25 and 26, the torsion bar 152 is wound by inserting the spline 152A side of the torsion bar 152 into the shaft hole 151A of the spool 151 and press-fitting between the protrusions 158A to 158E. The drum 151 is press-fitted and fixed in a relatively non-rotatable manner.

Further, as shown in FIGS. 25 to 27, the end of the winding drum 151 on the lock unit 9 side in the axial direction extends radially from the outer peripheral portion, and further outwards at a substantially right angle (FIG. 25). A flange portion 161 having a generally oval shape when viewed from the front is formed. On the inner side surface of the portion of the flange portion 161 that protrudes radially outward from the outer peripheral portion of the ratchet gear 35, a convex portion 162 having a generally chevron shape when viewed from the front is fitted with a wire 153 that protrudes radially outward from the ratchet gear 35. Is formed.

Further, a substantially V-shaped bent path 163 is formed on the outer peripheral portion of the convex portion 162 so that the wire 153 is slidably guided and pulled out (see FIG. 29). Therefore, when the wire 153 passes through the bending path 163, the wire 153 is bent and deformed at least at the V-shaped apex, and a drawing resistance is generated. In addition, window portions 164 are formed at two locations on the outer peripheral portion of the flange portion 161 so that the attached wire 153 can be visually recognized (see FIG. 29).

Further, a cylindrical tube portion 165 protrudes outward from the peripheral edge of the opening of the shaft hole 151A on the end surface of the winding drum 151 on the lock unit 9 side in the axial center direction. The cylindrical portion 165 is provided so as to surround the spline 152B on the other end side of the torsion bar 152 press-fitted into the shaft hole 151A with a predetermined gap.

Further, as shown in FIGS. 25, 26 and 28, the ratchet gear 35 is formed by aluminum die casting, zinc die casting, or the like, and has a substantially ring-shaped axial cross section and a ratchet gear portion 35A formed on the outer peripheral portion. A cylindrical fixed boss 166 is erected at the position. A spline groove 166 A into which a spline 152 B formed on the other end side of the torsion bar 152 is press-fitted is formed on the inner peripheral surface of the fixed boss 166. Further, the inner peripheral portion of the ratchet gear portion 35A is formed to have an inner diameter into which the cylindrical portion 165 of the winding drum 151 can be inserted.

In addition, the outer diameter of the spline 152B formed on the other end side of the torsion bar 152 is formed to be slightly smaller than the outer diameter of the spline 152A formed on one end side of the torsion bar 152.

As shown in FIGS. 28 and 29, the ratchet gear 35 has a ring-shaped flange that extends from the end surface portion of the ratchet gear portion 35A on the winding drum 151 side outward in the radial direction over the entire circumference. A portion 167 is formed. A wire fixing portion 168 is provided on the surface of the flange portion 167 facing the winding drum 151 side.

The wire fixing portion 168 includes a narrow convex portion 171 projecting in a C-shape in front view from the inner peripheral edge of the flange portion 167, and a webbing 3 among the opposing edge portions of the convex portion 171. The front edge portion 171A (the lower right edge portion 171A in FIG. 29) and the groove portion 172 having substantially the same width as the outer diameter of the wire 153 are projected in front view. A chevron-shaped convex portion 173 and a groove portion 175 having a width substantially the same as the outer diameter of the convex portion 173 and the wire 153 are formed, and an end edge portion 171B of the convex portion 171 on the drawing direction side of the webbing 3 (in FIG. And a substantially trapezoidal convex portion 176 protruding inward in the radial direction when viewed from the front so as to form a groove portion 177 having substantially the same width as the outer diameter of the wire 153. . The convex portion 171 is formed so as to have an arcuate outer peripheral surface having a C-shape in front view and coaxial with the fixed boss 166 in front view.

In addition, on the respective opposing surfaces of the

convex portions

171, 173, the

convex portions

173, 176, and the

convex portions

176, 171, ribs of the protrusions along the depth direction of the

groove portions

172, 175, 177 are provided. 179 is formed. In addition, the distance between the opposing ribs 179 of the

groove portions

172, 175, and 177 is formed to be smaller than the outer diameter of the wire 153.

Here, attachment of the wire 153 to the ratchet gear 35 and the take-up drum 151 will be described with reference to FIGS. 25, 26, and 29.
As shown in FIGS. 26 and 29, first, the bent portion 153A bent in a substantially S-shape on one end side of the wire 153 is changed into the

convex portions

171 and 173, the

convex portions

173 and 176 of the ratchet gear 35, respectively. In addition, the ribs 179 are squeezed into the

grooves

172, 175, and 177 formed by the

convex portions

176 and 171, respectively. Further, a front-side bent portion 153 B formed continuously from the bent portion 153 A of the wire 153 is projected outward from the outer periphery of the flange portion 167.

Further, an arc-shaped bent portion 153C formed continuously with the bent portion 153B of the wire 153 is disposed along the outer peripheral surface of the convex portion 171. As a result, the bent portion 153A on one end side of the wire 153 is fitted and fixedly held in the

grooves

172, 175 and 177 formed in the flange portion 167 of the ratchet gear 35, and the bent portion 153C of the wire 153 is flanged. It arrange | positions in the state facing the part 167. FIG.

Subsequently, the attachment of the wire 153 and the ratchet gear 35 to the take-up drum 151 is performed by first bending the bent portion 153B of the wire 153 protruding outward from the outer periphery of the flange portion 167 of the ratchet gear 35 in a front view. Is inserted into a curved path 163 formed on the outer peripheral portion of the convex portion 162 provided on the flange portion 161 of the winding drum 151.

At the same time, the fixed boss 166 of the ratchet gear 35 is inserted into the cylindrical portion 165 of the take-up drum 151, and the spline 152B formed on the other end side of the torsion bar 152 is press-fitted into the spline groove 166A of the fixed boss 166. To do. As a result, the wire 153 is disposed between the flange portion 161 of the winding drum 151 and the flange portion 167 of the ratchet gear 35, and the ratchet gear 35 is attached to the winding drum 151.

[Schematic configuration of pretensioner unit]
Next, a schematic configuration of the pretensioner unit 7 will be described with reference to FIGS. 2, 3, 30, and 31. FIG. 30 is an exploded perspective view of the pretensioner unit 7. FIG. 31 is a cross-sectional view showing the internal structure of the pretensioner unit 7.
The pretensioner unit 7 is configured to rotate the take-up drum 151 in the webbing take-up direction in an emergency such as a vehicle collision to remove the slack of the webbing 3 and firmly restrain the occupant to the seat.

As shown in FIGS. 30 and 31, the pretensioner unit 7 includes a gas generating member 181, a pipe cylinder 182, a piston 183, a pinion gear 185, a clutch mechanism 186, and a bearing 205.
The gas generating member 181 includes a gas generating agent such as explosive, and is configured to ignite the gas generating agent by an ignition signal from a control unit (not shown) and generate gas by combustion of the gas generating agent. Yes.

Further, the pipe cylinder 182 is formed as an L-shaped cylinder member in which a gas introduction part 182B is connected to one end of a linear piston guide cylinder part 182A. A gas generating member 181 is accommodated in the gas introduction part 182B. Therefore, the gas generated by the gas generating member 181 is introduced from the gas introduction part 182B into the piston guide cylinder part 182A. Further, an opening 187 is formed in the longitudinal intermediate portion on one side of the piston guide cylinder portion 182A, and a part of the pinion gear teeth 185A of the pinion gear 185 is disposed as will be described later.

The pipe cylinder 182 is sandwiched between the base plate 188 on the side wall 13 side of the housing 11 and the outer cover plate 191, and is sandwiched between the base block 192 and the cover plate 191. The screw 15 is attached and fixed to the outer surface of the side wall 13.

Further, the pretensioner unit 7 is attached to the side wall portion 13 at the upper end portion of the piston guide cylinder portion 182A, and a stopper pin 16 that functions as a piston 183 retaining member, a pipe cylinder 182 retaining member, and a rotation stopper can be inserted. A pair of through holes 182C are formed to face each other.

The piston 183 is formed of a metal member such as a steel material, has a substantially rectangular cross section that can be inserted from the upper end side of the piston guide cylinder portion 182A, and has a long shape as a whole. A rack 183A that meshes with the pinion gear teeth 185A is formed on the side surface of the piston 183 on the pinion gear 185 side. The end surface of the piston 183 on the gas generating member 181 side is formed as a circular end surface 183B corresponding to the cross-sectional shape of the piston guide cylinder portion 182A. A seal plate 193 formed of a rubber material or the like is attached to the circular end surface 183B.

The piston 183 has a through-hole 183C having a long cross-sectional rectangular shape along the longitudinal direction thereof, and both side surfaces thereof are communicated with each other. Further, a gas vent hole 195 communicating with the through hole 183 C from the pressure receiving side surface for receiving the gas of the seal plate 193 is formed in the piston 183 and the seal plate 193. As shown in FIG. 31, before the pretensioner unit 7 operates, that is, when the piston 183 is in a normal standby state where no gas is generated by the gas generating member 181, the rack 183A is not connected to the pinion gear teeth 185A. The piston guide cylinder portion 182A is inserted and arranged to the back side up to the meshing position.

The pinion gear 185 is a columnar member made of steel or the like, and pinion gear teeth 185A that can mesh with the rack 183A are formed on the outer periphery thereof. In addition, a cylindrical support portion 185B extending from the pinion gear teeth 185A toward the cover plate 191 is formed. This support portion 185B is rotatably fitted in a support hole 196 formed in a cover plate 191 attached to the side wall portion 13.

In a state where the support portion 185B is rotatably fitted in the support hole 196, a part of the pinion gear teeth 185A is disposed in the opening 187 of the piston guide cylinder portion 182A. As shown in FIG. 31, when the piston 183 moves from the normal standby state to the tip end side of the piston guide cylinder portion 182A, the rack 183A meshes with the pinion gear teeth 185A, and the pinion gear 185 rotates in the webbing take-up direction. To do.

The rotation of the pinion gear 185 is transmitted to the winding drum 151 via the clutch mechanism 186.
That is, a cylindrical boss portion 185D protruding along the axial direction is formed at the end portion of the pinion gear 185 on the side wall portion 13 side in the axial direction. Three splines each having an outer diameter of the base end portion are formed on the outer peripheral surface of the boss portion 185D at intervals of about 120 degrees in the central angle. The boss portion 185D is rotatably fitted in a through hole 197 formed in the base plate 188, and is disposed so as to protrude toward the winding drum 151 side.

Also, the clutch mechanism 186 rotates the pinion gear 185 from the state in which the winding drum 151 is freely rotated with respect to the pinion gear 185 (the state in which the clutch pawl 202 is housed) in the normal state, when the pretensioner unit 7 is operated. It is configured to be able to be switched to a state where it is transmitted to the winding drum 151 (a state where the clutch pawl 202 protrudes).

The clutch mechanism 186 is formed of a pawl base 201 made of steel or the like, three clutch pawls 202 made of steel or the like, and a synthetic resin such as polyacetal. It is comprised from the substantially annular pawl guide 203 which supports.

At the center of the pawl base 201, there are provided fitting holes 206 in which three spline grooves are formed at intervals of about 120 degrees of central angles so that the bosses 185D of the pinion gear 185 are fitted. By press-fitting the boss portion 185D, the pawl base 201 is attached to the pinion gear 185 so as not to rotate relative to the pinion gear 185. That is, the pawl base 201 and the pinion gear 185 are configured to rotate integrally.

Then, in a state where the boss portion 185D is press-fitted into the fitting hole 206 of the pawl base 201, a bearing 205 made of a synthetic resin material such as polyacetal is fitted into the cylindrical boss portion 185D. Further, a boss 157 erected at the center position of the end surface portion of the winding drum 151 on the pretensioner unit 7 side is rotatably fitted in the bearing 205. Each clutch pawl 202 is supported on the pawl base 201 in an accommodation posture. The accommodated posture is a posture in which each clutch pawl 202 is accommodated within the outer peripheral edge of the pawl base 201.

The pawl guide 203 is a substantially annular member, and is disposed at a position facing the pawl base 201 and each clutch pawl 202. Three positioning protrusions (not shown) are projected on the side surface of the pawl guide 203 on the base plate 188 side, and the positioning protrusions are inserted into the positioning holes 188A of the base plate 188. The pawl guide 203 is fixedly attached to the base plate 188 in a non-rotatable state.

Further, on the surface of the pawl guide 203 on the side of the pawl base 201, each posture changing projection 203A is protruded corresponding to each clutch pawl 202. Then, when the pawl base 201 and the pawl guide 203 are rotated relative to each other by the operation of the pretensioner unit 7, each clutch pawl 202 is brought into contact with the posture changing projection 203A, and the posture is changed from the housed posture to the locked posture. It is like that. The locking posture is a posture in which the tip end portion of the clutch pawl 202 protrudes outward from the outer peripheral edge portion of the pawl base 201.

Also, when each clutch pawl 202 changes its position to the locked position, it engages with the winding drum 151. Specifically, the clutch mechanism 186 is fitted to the boss 157 of the take-up drum 151 via the bearing 205 and rotatably supports the take-up drum 151, and each clutch pawl 202 has an outer peripheral edge of the pawl base 201. When projecting outward, the inner gear 156 formed on the inner peripheral surface of the flange portion 155 can be engaged.

Then, when each clutch pawl 202 is changed to the locked posture, the tip end portion of each clutch pawl 202 is engaged with the internal gear 156, whereby the pawl base 201 rotates the winding drum 151. The engagement between the clutch pawl 202 and the internal gear 156 is an engagement structure in only one direction that rotates the winding drum 151 in the winding direction of the webbing 3.

Further, once engaged, the clutch pawls 202 are engaged with the internal gear 156 with deformation, and when the take-up drum 151 rotates in the webbing pull-out direction after the engagement, the pinion gear 185 is moved by the pretensioner unit 7. The piston 183 is rotated back in the direction opposite to the operating direction by rotating it through the clutch mechanism 186 in the direction opposite to the direction of operation. When the piston 183 is pushed back to a position where the engagement between the rack 183A of the piston 183 and the pinion gear teeth 185A of the pinion gear 185 is disengaged, the pinion gear 185 is disengaged from the piston 183, so that the winding drum 151 rotates freely with respect to the piston 183. become able to.

Next, the operation of the pretensioner unit 7 configured as described above to operate and wind up the webbing 3 will be described with reference to FIGS. 31 and 32. FIG. 32 is an explanatory diagram showing the operation of the pawl 23 when the vehicle collides.
As shown in FIG. 31, when the gas generating member 181 of the pretensioner unit 7 is activated in the event of a vehicle collision or the like, the piston 183 moves toward the tip side of the piston guide cylinder portion 182A by the pressure of the generated gas. At the same time, the pinion gear 185 having the pinion gear teeth 185A engaged with the rack 183A rotates (rotates counterclockwise in FIG. 31).

Further, in the event of a vehicle collision or the like, the inertial mass body 52 of the vehicle acceleration sensor 28 moves on the bottom surface of the sensor holder and rotates the sensor lever 53 upward in the vertical direction. The claw 53A rotates the pilot lever 86 upward in the vertical direction. Then, the engaging claw portion 86 A of the pilot lever 86 is brought into contact with a locking gear tooth 81 A formed on the outer peripheral portion of the locking gear 81.

The engagement between the engagement claw portion 86A of the pilot lever 86 and the locking gear teeth 81A is an engagement structure in only one direction that operates in a direction that does not rotate the winding drum 151 in the pull-out direction of the webbing 3. . Therefore, when the pretensioner unit 7 is in operation, the winding drum 151 rotates smoothly in the winding direction of the webbing 3 even if the engaging claw 86A of the pilot lever 86 abuts against the locking gear teeth 81A. To do.

Then, as shown in FIG. 31, when the pinion gear 185 rotates, the pawl base 201 rotates together with the pinion gear 185. At this time, since the pawl base 201 rotates relative to the pawl guide 203, each posture changing projection 203A formed on the pawl guide 203 comes into contact with the clutch pawl 202, and each clutch pawl 202 is locked. Changed to posture.

As a result, the front end of each clutch pawl 202 engages with the internal gear 156 of the take-up drum 151, and the force that the piston 183 tries to move to the front end side of the piston guide cylinder 182A causes the pinion gear 185, the pawl. It is transmitted to the take-up drum 151 via the base 201, each clutch pawl 202 and the internal gear 156, and the take-up drum 151 is rotationally driven in the take-up direction of the webbing 3, and the webbing 3 is taken up by the take-up drum 151. It is done.

Further, when the pretensioner unit 7 is actuated at the time of a vehicle collision or the like, when the webbing 3 is subsequently pulled out and the take-up drum 151 is rotated in the webbing pulling direction, the engaging claw portion 86A of the pilot lever 86 is provided. Is engaged with a locking gear tooth 81 A formed on the outer peripheral portion of the locking gear 81, the clutch 85 is rotated, and the pawl 23 guided to the guide hole 116 of the clutch 85 is moved to the ratchet gear portion of the ratchet gear 35. 35A is engaged.

Accordingly, when the webbing 3 is subsequently pulled out after the pretensioner unit 7 is actuated at the time of a vehicle collision or the like, the ratchet gear 35 of the winding drum unit 6 is engaged by the engagement between the pawl 23 and the ratchet gear teeth 35A. Is prevented from rotating in the direction in which the webbing 3 is pulled out. The pawl 23 and the ratchet gear teeth 35 A are engaged in only one direction in which the take-up drum 151 is rotated in the drawing direction of the webbing 3.

[Energy absorption]
Next, after the pretensioner unit 7 is actuated at the time of a vehicle collision or the like, the occupant is moved forward relative to the vehicle while the engagement between the pawl 23 and the ratchet gear portion 35A of the ratchet gear 35 is still maintained. When the webbing 3 is moved, a large pulling force acts on the webbing 3. When the pulling output acting on the webbing 3 exceeds a predetermined value set in advance, a rotational torque in the webbing pulling direction acts on the winding drum 151.

The spline 152A side press-fitted and fixed to the inner side of the shaft hole 151A of the winding drum 151 of the torsion bar 152 is rotated by the rotational torque in the webbing pull-out direction acting on the winding drum 151, and the shaft portion of the torsion bar 152 is rotated. The torsional deformation of 152C is started. As the shaft portion 152C of the torsion bar 152 is twisted and deformed, the take-up drum 151 rotates in the pull-out direction of the webbing 3, and the impact energy is absorbed by the torsional deformation of the torsion bar 152 as the “first energy absorbing mechanism”. Made.

At the same time, when the take-up drum 151 is rotated, the pawl 23 and the ratchet gear 35 are engaged with each other, so that relative rotation occurs between the ratchet gear 35 and the take-up drum 151. Accordingly, relative rotation occurs between the wire 153 and the ratchet gear 35 as the winding drum 151 rotates, and the impact energy is absorbed by the wire 153 as the “second energy absorbing mechanism”.

[Wire drawing operation]
Here, the operation of the wire 153 when absorbing impact energy by the wire 153 will be described with reference to FIGS. 29 and 33 to 36. FIG. 33 to FIG. 36 are diagrams for explaining the operation of pulling out the wire 153.
As shown in FIG. 29, in the initial state of the ratchet gear 35 and the flange portion 161, the ratchet gear 35 is formed by the convex portion 176 constituting the wire fixing portion 168 and the end edge portion 171 B of the convex portion 171. One end side of the groove portion 177 is located near the pull-out side end portion of the bent path 163 formed on the outer peripheral portion of the convex portion 162 of the flange portion 161 so that the end portions of the groove portion 177 and the bent path 163 are in a straight line. Opposite to.

Further, the bent portion 153A of the wire 153 is fixedly held in the

respective groove portions

172, 175, 177 of the wire fixing portion 168 constituted by the respective

convex portions

171, 173, 176 of the ratchet gear 35. Further, a dogleg-shaped bent portion 153B continuous to the bent portion 153A of the wire 153 is inserted into a bent path 163 formed on the outer peripheral portion of the convex portion 162 of the flange portion 161.

As shown in FIGS. 33 to 36, when the winding drum 151 rotates in the pulling-out direction of the webbing 3 by pulling out the webbing 3, the ratchet gear 35 is prevented from rotating by the pawl 23, and the winding drum 151 With this rotation, the convex portion 162 of the flange portion 161 is relatively rotated in the drawing direction X3 of the webbing 3.

As a result, the wire 153 in which the bent portion 153A is fixedly held in the

grooves

172, 175, and 177 of the wire fixing portion 168 formed by the

convex portions

171, 173, and 176 of the ratchet gear 35 is protruded from the flange portion 161. While being sequentially squeezed from a substantially V-shaped bent path 163 formed on the outer peripheral portion of the portion 162 in a front view, it is drawn in the direction of the arrow X5 and wound around the outer peripheral surface of the convex portion 171. At this time, the torsion bar 152 is also twisted and deformed with the rotation of the winding drum 151 at the same time as the wire 153 is pulled out.

Further, when the wire 153 passes through the bending path 163 having a substantially V shape in front view while being deformed, sliding resistance is generated between the convex portion 162 and the wire 153, and bending resistance is generated by the wire 153 itself. The impact energy is absorbed by the wire 153 by the sliding resistance and the drawing resistance due to the bending resistance.

Then, as shown in FIG. 36, when the other end portion of the wire 153 is detached from the bending path 163 as the winding drum 151 rotates, the impact energy absorbing action by the wire 153 is finished. With the rotation of the winding drum 151, only the impact energy is absorbed by the torsional deformation of the torsion bar 152.

As described in detail above, in the seatbelt retractor 1 according to the present embodiment, the pilot lever 86 is rotatable to the mounting boss 121 in which the cylindrical shaft portion 118 is erected on the lower end edge of the clutch 85. It is inserted. In the pilot lever 86, the outer peripheral surface of the shaft portion 118 that is normally inserted into the mounting boss 121 forms a predetermined gap 128 with the load receiving surface 126 of the pilot lever support block 125 protruding from the clutch 85. The engaging claw portion 86A is rotated downward. Further, the pilot lever 86 has an engaging claw 86A engaged with the locking gear teeth 81A by swinging upward in the sensor lever 53 in an emergency, and the shaft 118 by rotating the locking gear 81 in the webbing pull-out direction. When the mounting boss 121 is bent by being pushed to the side, the outer peripheral surface of the shaft portion 118 is brought into contact with the load receiving surface 126 of the pilot lever support block 125.

Thereby, even if the engaging claw portion 86A engages with the locking gear teeth 81A and the mounting boss 121 is bent by receiving the pressing load toward the shaft portion 118, the pilot lever 86 has an outer peripheral surface of the shaft portion 118, Even if a large pressing load is applied by the locking gear 81, the mounting boss 121 and the shaft portion 118 can be deformed with a simple configuration because the predetermined gap 128 is formed and abuts against the load receiving surface 126 of the opposing pilot lever support block 125. And damage can be prevented. Further, by increasing the cross-sectional shape of the pilot lever support block 125, the mechanical strength of the pilot lever support block 125 can be increased, and the deformation and breakage of the mounting boss 121 and the shaft portion 118 can be reliably prevented. Can do.

Further, the pilot lever 86 that has received a pressing load from the locking gear 81 has an outer peripheral surface of the shaft portion 118 that abuts against the load receiving surface 126 of the pilot lever support block 125, so that the tip of the engaging claw portion 86 A and the shaft portion 118 There is no need to provide a member that abuts and supports the pressing load. Therefore, the entire length of the engaging claw portion 86A can be shortened to reduce the size, and even if the engaging claw portion 86A is formed in a thick shape, the mechanical strength of the pilot lever 86 is improved and the mass is increased. Can be reduced in weight.

Further, in the normal state, the outer peripheral surface of the shaft portion 118 fitted into the mounting boss 121 forms a predetermined gap with the load receiving surface 126 of the pilot lever support block 125, and the engaging claw portion 86A rotates downward due to its own weight. Therefore, by downsizing the pilot lever 86, the sensitivity of the vehicle acceleration sensor 28 to swing upward can be improved, and the sensitivity of the vehicle acceleration sensor 28 can be improved. be able to. Further, since a predetermined gap 128 is formed between the outer peripheral surface of the shaft portion 118 fitted into the mounting boss 121 and the load receiving surface 126 of the pilot lever support block 125, the shaft portion 118 is connected to the mounting boss 121. It can be easily inserted and the assembly work can be made more efficient.

Further, since the load receiving surface 126 of the pilot lever support block 125 is formed so as to be recessed in an arc shape coaxially with the mounting boss 121, the engaging claw portion 86A engages with the locking gear teeth 81A in the event of an emergency. When the boss 121 is bent, the outer peripheral surface of the shaft portion 118 is brought into contact with the load receiving surface 126. As a result, the pressing load received by the pilot lever 86 can be received by the load receiving surface 126 that is recessed in an arc through the outer peripheral surface of the cylindrical shaft portion 118, and the pressing load can be received on the entire surface of the load receiving surface 126. Accordingly, the mounting boss 121 and the shaft portion 118 can be reliably prevented from being deformed or damaged.

In addition, the pilot lever support block 125 can be supported by distributing the pressing load with the load receiving surface 126 that is recessed in an arc shape, and the pilot lever support block 125 can be reduced in size. The clutch 85 can be downsized. In addition, the load receiving surface 126 of the pilot lever support block 125 normally forms a predetermined gap 128 with the outer peripheral surface of the shaft portion 118 that is inserted into the mounting boss 121, so that the shaft portion 118 is inserted into the mounting boss 121. In this way, it is possible to configure a guide surface for the assembly work and further improve the efficiency of the assembly work.

Further, since the pilot lever support block 125 protrudes so as to be almost the same height as the mounting boss 121, the shaft portion 118 of the pilot lever 86 is brought into contact with the pilot lever support block 125 over almost the entire length. It is possible to prevent the mounting boss 121 and the shaft portion 118 from being deformed or damaged.

Further, in the seatbelt retractor 1 according to the present embodiment, the pilot lever 86 is pivotally supported so that the shaft portion 118 is fitted and fitted to the mounting boss 121 provided upright at the lower end portion of the clutch 85. . When the pilot lever 86 is rotated downward in the vertical direction by its own weight, the receiving plate portion 122 with which the lock claw 53A of the sensor lever 53 abuts is extended substantially horizontally from the lower end edge portion of the clutch 85. It is located in the opening 127 formed in the extending portion 117 having a horizontally long plate shape. In an emergency, even when the engaging claw portion 86A of the pilot lever 86 is engaged with the locking gear tooth 81A due to the swing of the sensor lever 53 in the vertical direction, the receiving plate portion 122 of the pilot lever 86 is The clutch 85 is rotated in a state where it is located in the opening 127.

As a result, the shaft 118 of the pilot lever 86 is fitted into the mounting boss 121 provided upright on the lower end of the clutch 85 and pivotally supported so that the receiving plate 122 of the pilot lever 86 is supported by the lower end of the clutch 85. The locking gear 81 is relatively non-rotatable and coaxially attached to one end side of the shaft portion 76 of the ratchet gear 35 in a state in which the locking gear 81 is inserted into the opening 127 formed in the extending portion 117 extending from the edge portion. Accordingly, the pilot lever 86 can be attached to the clutch 85.

Further, even if the pilot lever 86 is pressed and rotated by the lock claw 53A of the sensor lever 53 swinging upward in the vertical direction, the receiving plate portion 122 with which the lock claw 53A of the sensor lever 53 abuts is Since the state of entering the opening 127 formed in the extending portion 117 extending from the lower end edge portion is maintained, the pilot lever 86 is reliably prevented from coming off from the mounting boss 121 with a simple configuration. be able to.

Further, the pilot lever 86 on which the shaft portion 118 is pivotally supported by the mounting boss 121 may be formed with an engaging claw portion 86A and a receiving plate portion 122 below the engaging claw portion 86A. The receiving plate portion 122 is opened so as to be able to enter a horizontally long plate-like extending portion 117 extending substantially horizontally from the lower end edge portion, and the lock claw 53A of the sensor lever 53 swinging vertically upward can enter. Therefore, the shape of the parts of the pilot lever 86 and the clutch 85 can be simplified, and the quality control of the shape and the assembly work of the lock unit 9 can be simplified.

Further, after the engaging claw portion 86A of the pilot lever 86 is attached to the mounting boss 121 while being brought into contact with the annular rib portion 113 of the clutch 85, the receiving plate portion 122 of the pilot lever 86 is placed in the opening 127. The locking gear 81 can be attached by making it enter. As a result, even if the annular rib 113 of the clutch 85 is placed close to the inner peripheral surface of the locking gear tooth 81A and coaxial with the locking gear tooth 81A, the pilot lever 86 is easily attached to the mounting boss 121. The pilot lever 86 can be reliably prevented from coming off the mounting boss 121 with a simple configuration.

The pilot lever 86 is formed so as to project the engagement claw portion 86A and the receiving plate portion 122 toward the tangential opening 127 so as to face each other from the outer peripheral surface of the shaft portion 118 formed in a cylindrical shape. Therefore, the part shape of the pilot lever 86 can be further simplified, and the shape quality control can be simplified and the weight can be reduced.

Further, when the pilot lever 86 is rotated downward in the vertical direction by its own weight, the base end portion of the receiving plate portion 122 abuts on the peripheral edge portion of the opening portion 127 formed in the extending portion 117, and A portion on the front end side of the receiving plate portion 122 enters the opening 127. Thereby, the rotation angle of the pilot lever 86 can be regulated with a simple configuration, and the parts shapes of the clutch 85 and the pilot lever 86 can be further simplified.

Note that the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the scope of the present invention.

Claims

A housing;
A winding drum that is rotatably stored in the housing and winds and stores the webbing;
A ratchet gear that rotates integrally with the winding drum;
A locking mechanism for preventing the winding drum from rotating in the webbing pull-out direction in an emergency;
An inertial mass that swings in response to an acceleration greater than a predetermined value of the vehicle;
A sensor lever that is pushed by the inertial mass body and swings to activate the lock mechanism;
With
The locking mechanism is
A clutch that is rotatably arranged coaxially with the winding drum, and that engages the ratchet gear by rotation to induce a pawl that prevents rotation of the winding drum in the webbing pull-out direction;
A pilot lever that is pivotally supported by a mounting boss that is erected on the clutch and is rotated by being pressed by the swinging sensor lever;
A locking gear that is integrally and coaxially attached to the take-up drum, and that engages the pilot lever by rotation;
Have
The pilot lever is
A cylindrical shaft portion rotatably inserted into the mounting boss;
An engaging claw that protrudes from the outer peripheral surface of the shaft and engages the locking gear;
Have
The clutch is a pilot lever support portion projecting so as to be opposed to the outer peripheral surface on the opposite side in the radial direction with respect to the engagement claw portion of the shaft portion fitted into the mounting boss. Have
In the pilot lever, the outer peripheral surface of the shaft portion that is normally inserted into the mounting boss forms a predetermined gap with the pilot lever support portion, and the engagement claw portion rotates by its own weight. When the engaging claw is engaged with the locking gear by the swinging of the sensor lever and is pressed by the rotation of the locking gear in the webbing pull-out direction, the mounting boss is bent. A retractor for a seat belt, wherein the clutch is rotated according to the rotation of the locking gear in a state where an outer peripheral surface is in contact with the pilot lever support portion.
The pilot lever support portion has a load receiving surface formed so as to be recessed in an arc shape coaxially with the mounting boss,
The load receiving surface is opposed to the outer peripheral surface of the shaft portion that is normally inserted into the mounting boss so as to form the predetermined gap, and the engaging claw portion engages with the locking gear in an emergency, The retractor for a seat belt according to claim 1, wherein when the mounting boss is bent, an outer peripheral surface of the shaft portion is brought into contact with the load receiving surface.
The seat belt according to claim 1 or 2, wherein the pilot lever support portion is provided so as to be substantially the same height as the shaft portion fitted into the mounting boss. Retractor.
A housing;
A winding drum that is rotatably stored in the housing and winds and stores the webbing;
A ratchet gear that rotates integrally with the winding drum;
A locking mechanism for preventing rotation of the winding drum in the webbing pull-out direction in an emergency;
An inertial mass that swings in response to an acceleration greater than a predetermined value of the vehicle;
A sensor lever which is pushed by the inertial mass body and swings upward in the vertical direction to activate the lock mechanism;
With
The locking mechanism is
A clutch that is rotatably arranged coaxially with the winding drum, and that engages the ratchet gear by rotation to induce a pawl that prevents rotation of the winding drum in the webbing pull-out direction;
A pilot lever that is pivotally supported by a mounting boss that is erected on the clutch and is rotated by being pressed by the swinging sensor lever;
A locking gear that is integrally and coaxially attached to the take-up drum, and that engages the pilot lever by rotation;
Have
The pilot lever is
A shaft portion into which the mounting boss is rotatably inserted;
An engaging claw for engaging with the locking gear;
An abutting portion on which the swung sensor lever abuts and is pressed;
Have
The clutch is
From the lower end edge portion, with the shaft portion inserted and inserted into the mounting boss, it has an extending portion that extends to face the mounting boss,
The extension portion is opened so that the contact portion of the pilot lever rotated by its own weight in the vertical direction can enter, and the sensor lever that swings upward in the vertical direction can be entered. Has an opening,
The pilot lever rotates the locking gear in a state where the contact portion is located in the opening when the engaging claw is engaged with the locking gear by swinging the sensor lever in an emergency. And retracting the clutch according to the above.
The clutch has an annular rib portion erected coaxially with the locking gear close to the inner peripheral surface of the locking gear;
When the pilot lever is pivotally supported by the mounting boss and abuts the tip of the engaging claw on the rib, the abutment is perpendicular to the opening. The retractor for a seat belt according to claim 4, wherein the retractor is located on an upper side in the direction.
The shaft portion is formed in a cylindrical shape,
The engaging claw portion protrudes from the outer peripheral surface of the shaft portion facing the locking gear toward the opening portion in the tangential direction,
The seat belt according to claim 4 or 5, wherein the abutting portion protrudes from the outer peripheral surface of the shaft portion facing the extending portion toward the opening in the tangential direction. Retractor.
The mounting boss is provided so that the shaft portion fitted into the mounting boss is located in the vicinity of the peripheral edge of the opening,
When the pilot lever pivots downward in its vertical direction under its own weight, the base end portion of the contact portion comes into contact with the peripheral edge portion of the opening portion, and the tip side portion of the corresponding contact portion is in the opening portion. The retractor for a seat belt according to claim 6, wherein the retractor enters the seat.