WO2018183600A1

WO2018183600A1 - Retractor pretensioner clutch

Info

Publication number: WO2018183600A1
Application number: PCT/US2018/025020
Authority: WO
Inventors: Zhide David FENG; Dongfei HUANG
Original assignee: Feng Zhide David; Huang Dongfei
Priority date: 2017-03-29
Filing date: 2018-03-29
Publication date: 2018-10-04

Abstract

A pretensioner clutch apparatus for a webbing of a seatbelt retractor for use by an occupant in a vehicle has a retractor bracket, a spool pivotally connected to the retractor bracket. A pin connects the spool and bracket. The pin can either be an independent part or part of the spool. The retractor also has a cylinder, a piston and a MGG (Micro Gas Generator) providing the necessary force to move the piston. The pretensioner clutch has an internal member that is fixed with the pin. The internal member has external teeth on its basically round circumference. The external member is elastically connected to the bracket. A connecting member is selected from a group of a cable or a strap.

Description

INVENTION TITLE

RETRACTOR PRETENSIONER CLUTCH

FIELD OF THE INVENTION

[0001 ] The present invention relates to a pretensioner clutch for a seatbelt for tightening the webbing of said seatbelt when there is a collision involving a vehicle installed with said seatbelt.

BACKGROUND OF THE INVENTION

[0002] Current pretensioners are generally bulky and expensive.

Seatbelt pretensioners need to allow the user to adjust the seatbelt while providing restraint when involved in an acceleration event. They have a greater risk of not operating properly and getting stuck. There is a need for a pretensioner with a clutch that is reliable, safe and economical.

SUMMARY OF THE INVENTION

[0003] A pretensioner clutch apparatus for a webbing of a seatbelt retractor for use by an occupant in a vehicle has a retractor bracket, a spool pivotal ly connected to the retractor bracket. A pin connects the spool and bracket. The pin can either be an independent part or part of the spool. The retractor also has a cylinder, a piston and a MGG (Micro Gas Generator) providing the necessary force to move the piston. The pretensioner clutch has an internal member that is fixed with the pin. The internal member has external teeth on its basically round circumference. The external member is elastically connected to the bracket. A connecting member is selected from a group of a cable or a strap.

[0004] Other features and advantages of the instant invention will become apparent from the following description of the invention which refers to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Fig. 1 shows an isometric view of a pretensioner according to an embodiment of the current invention.

[0006] Fig. 2 shows a view of the pretensioner shown in figure 1 by a section cut through a center line of the cylinder.

[0007] Fig. 3 shows the pretensioner in an exploded view.

[0008] Fig. 4 shows the structures of an external member, an internal member and a spool of the pretensioner shown in figure 1 .

[0009] Fig. 5 shows the position of the external member and the internal member before the pretensioner is actuated.

[001 0] Fig. 6 shows the position of the external member and the internal member after the pretensioner is actuated.

[001 1 ] Fig. 7 shows another embodiment of a pretensioner before actuation.

[001 2] Fig. 8 shows the pretensioner shown in figure 7 after actuation. [001 3] Fig. 9 is an exploded isometric view of a pretensioner according to an embodiment of the invention.

[0014] Fig. 10 is a cutaway view of the pretensioner shown in figure 9.

[001 5] Fig. 1 1 is an isometric view with a portion cutaway showing an internal structure of the pretensioner shown in figure 9.

[001 6] Fig. 1 2 is a front view after a section cut of the pretensioner shown in figure 9.

[001 7] Fig. 1 3 is a detailed view of an inner race element of the pretensioner shown in figure 9.

[001 8] Fig. 14 is a detailed view of a locking element of the

pretensioner shown in figure 9.

DETAILED DESCRIPTION OF THE INVENTION

[001 9] In the following detailed description of the invention, reference is made to the drawings in which reference numerals refer to like elements, and which are intended to show by way of illustration specific embodiments in which the invention may be practiced. It is understood that other embodiments may be utilized and that structural changes may be made without departing from the scope and spirit of the invention.

[0020] Referring to figures 1 -6, a retractor pretensioner 10 has a base bracket 22 which pivotally holds a spool 24. When spool 24 rotates, a webbing (not shown) can be taken up or released by spool 24.

[0021 ] Pretensioner 1 0 has a clutch 30 having an internal member 32 and an external member 34. Internal member 32 is fixed with spool 24, and can be turned together with spool 24. Internal member 32 has a plurality of external teeth 33. External member 34 has a hole 35 whose circumference has a plurality of teeth 36. External member 34 also has a flange 37 and a connecting element 38 for holding a cable or strap 95.

[0022] During normal operation in an un-deployed situation, external member 34 is held by base bracket 22 and an auxiliary bracket 42 which is fixed with base bracket 22, through a position element 52. Position element 52 is fixed with a wall 23 of base bracket 22, and with a side wall 44 of base bracket 42. Position element 52 has a polygon-shaped hole for engagement with a polygonal protrusion on flange 37. With above engagement, the center line of external member 34 is fixed.

[0023] The diameter of hole 35 is significantly bigger than that of internal member 32. When retractor pretensioner 10 is at normal operation, internal member 32 and external member 34 are concentric which allows internal member 32 in conjunction with spool 24 to freely turn at any angle without engagement between external teeth 33 and teeth 36.

[0024] Retractor pretensioner 1 0 also has an actuator unit 60, which has a cylinder 70 having a bore portion 72 and a shoulder 74. Actuator unit 60 also has a piston 80 engaged basically air-tight with cylinder 70. Piston 80 can slide in and out. An actuating profile 82 is a part of piston 80. A micro gas generator (MGG) 85 is engaged and fixed with shoulder 74.

Actuator unit 60 can be fixed with base bracket 22 directly, or through a connecting plate 90.

[0025] The first end of cable/strap 95 is connected to connecting element 38 of external member 34, then passes a curvature section defined by a round shank portion 39 of external member 34, then passes the MGG end of actuator unit 60, then makes a U-turn at actuating profile 82. The second end of 95 is fixed to connecting plate 90 by an end fitment 92.

[0026] When there is a crash or similar acceleration event, a vehicle equipped with retractor pretensioner 1 0, MGG 85 is fired by a control unit (not shown), then the high pressure gas produced by MGG 85 will drive piston 80 and actuating profile 82 away from cylinder 70 in the -X direction as defined at Fig. 1 . This action through cable/strap 95 creates both a translation force in the -X direction; and a rotational torque in the +Y direction (per rule of right-hand screw) that acts on external member 34. As shown in the figures, the force and torque will break or distort position element 52 first, then pulls the center line of external member 34 to move in the -X direction to let teeth 36 of external member 34 touch external teeth 33 of internal member 32, then teeth 36 will turn around center line of internal member 32 a little bit, then a tooth of teeth 36 is firmly engaged with a tooth of external teeth 33, then internal member 32 and spool 24 together are turned in the +Y direction, then the webbing surrounding spool 24 will be tightened.

[0027] Figures 7 and 8 show an embodiment of retractor pretensioner 10, which utilizes a clutch unit 1 60. Clutch unit 1 60 has a piston 1 80 having a tooth portion 1 82. Clutch unit 1 60 also has a pinion 1 32 having teeth 1 33 being engaged with tooth portion 1 82 at any time and having first pinion side tooth portion 1 34 at its first end and second pinion side tooth portion 1 36 at its second end. Clutch unit 160 also comprises a spool side tooth portion 1 72 which is physically fixed with a spool 1 24 which is pivotal ly installed with a retractor bracket 1 22. Clutch unit 160 also has an auxiliary gear 1 50 which is fixed with retractor bracket 1 22 in some way (can be fixed through a bracket similar to 42 of the above embodiment of this invention as is known in the art). Auxiliary gear 1 50 has an auxiliary gear side tooth portion 1 52. Both first pinion side tooth portion 1 34 and auxiliary side tooth portion 1 52 have a ramp shapes or tilted surfaces.

[0028] This embodiment also has a piston and MGG and control unit similar to the embodiment discussed above. Before the MGG is fired, first pinion side tooth portion 1 34 and auxiliary side tooth portion 1 52 are engaged with each other, and second pinion side tooth portion 1 36 is separated from spool side tooth portion 1 72. Therefore spool side tooth portion 1 72 and spool 1 24 can turn freely.

[0029] After the MGG is fired, piston 1 80 is driven down in the -Z direction, then pinion 1 32 is turned in the -Y direction, and pinion 1 32 is pushed translationally in the -Y direction due to the function of the ramp shaped portions of first pinion side tooth portion 1 34 and auxiliary side tooth portion 1 52, then second pinion side tooth portion 1 36 catches spool side tooth portion 1 72 and turns spool 1 24 in the -Y direction, thus tightening the webbing.

[0030] Referring now to figures 9 through 14, another embodiment of a retractor pretensioner is shown having a spool 224 with a shaft portion 226 and an outer race portion 228. Between shaft 226 and outer race portion 228, there is a annular recession space 227. On the inner face of said outer race portion 228, there is an engagement portion 229 that has teeth. An inner race element 230 is inserted in annular recession space 227. [0031 ] Inner race element 230 has at least one pocket 232 which is wedged shape, and also has an opening 234 which is cut annularly around the periphery of 230. At least one basically wedge shaped locking element 240 is placed at pocket 232. At least one locking element 240 has a tooth portion 246 on its outer surface and also has a recessed portion 244 which is cut laterally. It should be noted that locking element 240 will also work without tooth portion 246 with the shape frictionally applying the required locking function. An annular spring 250 surrounds inner race element 230 at opening 234, and surrounds at least one locking element 240 at its recessed portion 244. Annular spring 250 biases at least one locking element 240 to the centerline of shaft portion 226.

[0032] A shell portion 260 is coupled with inner race element 230 and also has a cable end receiver 266. A proximal end 295A of a cable 295 is fixed with cable end received 266, and cable's 295 distal end is connected with actuator unit 60 (Fig. 1 as discussed above). Cable 295 usually surrounds shell portion 260 for at least one rotation or more.

[0033] In an un-actuated condition, as shown at Fig. 1 5, shell portion 260, inner race element 230 and locking element 240 are stationary, and tooth portion 246 is not engaged with engagement portion 229, thus allowing spool 224 to turn freely corresponding to adjustment of the seatbelt by various occupants.

[0034] When actuator unit 60 is fired, cable 295 is pulled to turn shell portion 260, inner race element 230, and locking element 240 in a clockwise direction at above figures, then the centrifugal force in combination with the wedge shaped of pocket 232 drives locking element 240 to move centrifugally to overcome biasing force of annular spring 250, then tooth portion 246 is engaged with engagement portion 229, with locking element 240 staying inside pocket 232, then spool 224 has to turn together with inner race element 230 in clockwise direction in above figures.

[0035] Although the instant invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art.

Claims

WHAT IS CLAIMED IS:

1 . A clutch apparatus for a seatbelt having a base bracket which holds a spool for collecting a webbing for said seatbelt, said seatbelt also having a pretensioner generally fixed with said bracket, said clutch apparatus comprising:

an outer race extended from one polar end of said spool;

said outer race having an outer race annular inner face;

an inner race pivotal ly engaged with said spool;

said inner race being generally concentric with said outer race;

said inner race having at least one pocket;

at least one locking element;

said at least one locking element having a locking element outer face; and

said at least one locking element being generally wedged shaped and disposed in said at least one pocket.

2. A clutch apparatus for a seatbelt according to claim 1 wherein;

said outer race having an outer race tooth portion on said outer race annular inner face; and

said locking element having a locking element tooth portion on said locking element outer face.

3. A clutch apparatus for a seatbelt according to claim 1 , said inner race being engaged with said pretensioner; wherein a rotational movement is applied when said pretensioner is fired.

4. A clutch apparatus for a seatbelt according to claim 3, said inner race being engaged with said pretensioner through a shell portion, said shell portion being rotationally fixed with said inner race.

5. A clutch apparatus to said claim 2, said clutch apparatus further comprising an annular spring surrounding said at least one locking element and said inner race element.

6. A clutch apparatus for a seatbelt according to claim 1 wherein said at least one pocket is ramp-shaped.

7. A clutch apparatus for a seatbelt having a base bracket which holds a spool for collecting a webbing for said seatbelt, said seatbelt also having a pretensioner generally fixed with said bracket, said clutch apparatus comprising: a piston,

said piston having a piston tooth portion disposed on a side thereon;

a pinion;

said pinion having a plurality of teeth movably disposed within said piston tooth portion;

said pinion having a first end and a second end;

said pinion having a first pinion tooth portion disposed on said first end;

said pinion having a second pinion tooth portion disposed on said second end;

a spool side tooth portion fixedly attached to said spool;

said spool being rotatably disposed in said base bracket; an auxiliary gear fixedly disposed on said base bracket;

said auxiliary gear having an auxiliary gear side tooth portion; said first pinion side tooth portion being generally wedge shaped;

said auxiliary side tooth portion being generally wedge shaped; and

wherein when said piston in moved, said pinion is rotated and translated by said first pinion side tooth portion thereby rotating said spool.