Patent ID: 12208766

EMBODIMENTS

Now, an embodiment of a safety belt retractor according to the invention is described with reference toFIGS.1and2. It can be understood, the invention is not limited to the specific embodiment shown in the drawings. The safety belt retractor together with a webbing2schematically shown inFIG.1, as an overall system, may be referred to as a safety belt device.

The shown safety belt retractor comprises a belt reel1and a frame8, in which the belt reel1is rotatably supported and is configured for winding the webbing2. The safety belt retractor further comprises a sensing unit10, a locking mechanism4and a pretension device7, which are known in the prior art, as mentioned above. Here, the sensing unit10, the locking mechanism4, the pretension device7and a load limiting device3are all optional, and any one or more of these structural units may be spared according to the actual requirements. The sensing unit10may be a sensing unit for sensing an acceleration and/or a tilt angle of a vehicle and/or a pull-out acceleration of the webbing. The sensing unit10may also comprise a plurality of sub-units capable of sensing at least one of the just-mentioned parameters respectively. When the sensing unit10senses the emergency of the vehicle, for example, the vehicle is about to collide, the locking mechanism4may be activated by the sensing unit10.

It is common in the prior art that the sensing unit and the locking mechanism are arranged at a side of the frame, while the pretension device is arranged at the other side of the frame. On the contrary, in this embodiment of the present invention, the sensing unit10, the locking mechanism4and the pretension device7are all arranged at the same side of the frame8. More specifically, the sensing unit10is arranged at the side of a second support plate9facing away from a back plate8h, and at least a driven element such as a ball gear6of the pretension device7is arranged between the back plate8hand the second support plate9which will be explained later.

As shown inFIG.2, the frame8comprises: the back plate8hhaving a first side and a second side opposite to each other and having a first opening20; two first support legs8a,8bextending from the first side of the back plate and opposite to each other; a first support plate11having a second opening21and connected to free end regions of the first support legs; four second support legs8c,8d,8e,8fextending from the second side of the back plate; and the second support plate9connected to free end regions of the second support legs. The first opening20and the second opening21receive the belt reel1. The first support legs8a,8bmay be integrally formed with the back plate8h. The second support legs8c,8d,8e,8fmay also be integrally formed with the back plate8h.

InFIG.2, the two first support legs8a,8bare symmetrical with each other about a longitudinal axis of the safety belt retractor, and each have an end region bent inward, wherein the bent end region of each first support leg has two fixing portions for fixing the first support plate11. The first support plate11may be connected to the first support legs, for example, by bolts.

As can be seen fromFIG.2, the frame8has four distributed second support legs8c,8d,8e,8f, each of which has an end region bent inward and has one fixing portion for fixing the second support plate9in the bent end region. The four second support legs8c,8d,8e,8fmay be spaced apart from each other at a uniform angular interval with respect to the longitudinal axis of the safety belt retractor. The second support plate9may be connected to the free bent end regions of the second support legs8c,8d,8e,8f, for example, by bolts.

Here, the optional locking mechanism4is advantageously integrated in the safety belt retractor. The locking mechanism4may comprise a locking plate and a movable locking claw (not shown), wherein the locking plate is formed by the second support plate9. For this purpose, the second support plate9may have a third opening19, which may have an internal tooth system. The locking claw, when engaged with the internal tooth system, causes that the safety belt retractor is locked in the webbing pull-out direction.

The safety belt retractor may comprise a stop wheel5, which is rotation-fixedly connected to the belt reel1at an axial end of the belt reel1facing the back plate8h. The locking claw (not shown) of the locking mechanism4may be received in the stop wheel5, more specifically, may be received in a recess (not shown) of the stop wheel5.

The pretension device7may comprise a ball gear6rotation-fixedly fitted on the stop wheel5, and a steel ball shooting device. The steel ball shooting device, when activated, may shoot a plurality of steel balls to drive the ball gear6in the webbing winding direction, wherein the ball gear can drive the stop wheel5and in turn drive the belt reel1to rotate in the webbing winding direction. As a result, a pretension function of the safety belt retractor can be realized on requirements.

In the sense of the invention, it is not inevitably necessary that the entire pretension device7is completely positioned in a space between the back plate8hand the second support plate9. It can be understood that at least a portion of the entire pretension device7is positioned in the space between the back plate8hand the second support plate9. In particular, the driven element such as the ball gear6of the pretension device7, which is rotation-fixedly connected with the stop wheel5, may be completely positioned in the space between the back plate8hand the second support plate9. In particular, the driving element of the pretension device7, such as a snakelike element of the steel ball shooting device, may be only partially positioned in the space between the back plate and the second support plate, or even may be positioned completely outside this space.

It's particularly advantageous, the optional load limiting device3is integrated in the safety belt retractor. The load limiting device3rotation-fixedly connects the belt reel1with the stop wheel5, and can transmit a torque no more than a predetermined threshold value between the belt reel1and the stop wheel5. As shown inFIG.1, the load limiting device3may be configured as a torsion bar, which is received in a chamber of the belt reel1, and which is plastically deformable when a predetermined torsion load is exceeded, in order to limit the torque transmittable between the belt reel1and the stop wheel5through the torsion bar. The torsion bar has a first end3badjacent to the first opening20and a second end3aadjacent to the second opening21, and is rotation-fixedly connected to the stop wheel5at its first end3band is rotation-fixedly connected to the belt reel1at its second end3a.

If the optional load limiting device3as shown inFIG.1is spared, the belt reel1and the stop wheel5, as two separate components, may also be replaced with one integral belt reel, wherein a portion of the integral belt reel may have the function of the stop wheel5.

It is also possible that the pretension device7and the sensing unit10as shown inFIG.1exchange their positions. If the optional pretension device7shown inFIG.1is spared, the optional sensing unit10may also be arranged between the back plate8hand the second support plate9.

The safety belt retractor as shown inFIGS.1and2may operate as below:

When an emergency occurs to a vehicle equipped with the safety belt retractor as described above, for example, in case of an imminent collision or rollover of the vehicle, the sensing unit10may sense the emergency of the vehicle, and cause the locking claw of the locking mechanism4to move away from its rest position until the locking claw engages with the internal tooth system of the second support plate9. The engagement of the locking claw with the internal tooth system causes that the stop wheel5is stopped in the webbing pull-out direction, and thus the belt reel1is locked in the webbing pull-out direction. In this way, the belt reel1and the stop wheel5can only rotate in the webbing winding direction, and can't rotate in the webbing pull-out direction.

In addition, the pretension device7is activated, for example, a gas generator of a pyrotechnic pretension device is ignited, wherein the generated gas shoots the plurality of steel balls contained in a snakelike tube. The steel balls successively drive the ball gear6in the webbing winding direction, and thus the ball gear6drives the stop wheel5and in turn drives the belt reel1to rotate in the webbing winding direction. The steel ball shooting device may comprise a winding snakelike tube, which is provided with a gas generator at its one end and accommodates the plurality of steel balls, and which aims at the ball gear6at its other end. The steel balls shot out of the snakelike tube may impact the teeth of the ball gear and mesh into ball sockets between the teeth of the ball gear. InFIG.1, only a circular cross section of the snakelike tube is schematically shown.

If the torque to be transmitted between the stop wheel5and the belt reel1through the load limiting device3that is configured as a torsion bar exceeds a predetermined threshold value, the torsion bar can be plastically deformed, thereby limiting the maximal load of the safety belt retractor and thus limiting the peak value of the shoulder webbing force of the webbing2, and hence preventing the vehicle occupant from being injured due to the excessive peak value of the shoulder webbing force.

It's particularly advantageous, the first opening20and the second opening21may be configured as rotation bearings for the belt reel1. It's also advantageous, the second opening21may be configured as an axial stop for the belt reel1. Moreover, it's advantageous, the locking plate9may be configured as an axial stop for the stop wheel5. It's appropriate, the two axial ends of the safety belt retractor may be additionally provided with a respective end cover for covering some components of the safety belt retractor.

Finally, it should be pointed out, the above-mentioned specific embodiments are only for understanding the invention, and don't limit the protection scope of the invention. For those skilled in the art, modifications can be made on the basis of the specific embodiments, and such amendments don't depart from the protection scope of the invention.