Seat belt retractor

Abstract

The invention relates to a belt retractor (10) for a vehicle seat belt system, comprising a frame (12) and a belt reel (14) mounted in the frame (12), a coupling disc (20) being connected to the belt reel and being rotatable relative to the belt reel (14) by a predetermined amount, wherein a latching pawl (24) is arranged on the coupling disc (20) so as to be radially deflectable from an initial position, the latching pawl in the deflected position engaging in a locking engagement fastened to the frame in order to latch the coupling disc (20), wherein the latching pawl (24) is connected to the coupling disc (20) via two spring sections (42, 44), the spring sections being formed on at least one spring element, wherein the two spring sections (42, 44) each have a pawl-side end fastened to the latching pawl (24) and a coupling disc-side end fastened to the coupling disc (20).

Description

Technical Field

[0001] The invention relates to a seat belt retractor for a vehicle seat belt system. Background Art

[0002] In normal operation of the belt retractor, the belt can be pulled out of its belt reel overcoming only a small resistance. In contrast, in the locked state of the belt retractor, belt withdrawal is blocked in order to prevent further belt withdrawal. The locked state can be initiated in two ways: firstly vehicle-sensitive, i.e. if the acceleration forces acting on the vehicle exceed a certain threshold value, or belt-sensitive, i.e. if the acceleration acting on the belt in the belt withdrawal direction exceeds a predefined threshold value.

[0003] In the case of known belt retractors, the vehicle-sensitive or belt-sensitive locking of the belt reel is achieved via a coupling disc, which rotates together with the belt reel during normal operation, but is rotatable relative to the belt reel. If the coupling disc lags behind the rotation of the belt reel, the relative rotation causes a locking pawl mounted on the belt reel to be pivoted out, which engages in a locking engagement on the belt retractor frame on which the belt reel is mounted. In normal operation, the locking pawl rotates together with the belt reel.

[0004] For the vehicle-sensitive initiation of the latching, the coupling disc is provided with a toothing into which a latching element of an acceleration sensor fixed to the vehicle can engage in order to hold the coupling disc behind the rotation of the belt reel. For the belt-sensitive activation of the latching, an inertia element is provided on the coupling disc, which, due to the mass inertia, holds the coupling disc behind the rotation of the belt reel. Summary of the invention

[0005] The object of the present invention is to minimize the noise generated during normal operation of a seat belt retractor.

[0006] This object is achieved by a seat belt retractor. In a seat belt retractor of this type for a vehicle seat belt system, which has a frame and a seat belt reel mounted in the frame, to which a coupling disc is connected, and which can be rotated relative to the seat belt reel by a predetermined degree, a latching pawl is arranged on the coupling disc so as to be radially deflectable from an initial position, which latching pawl engages in a locking engagement fixed to the frame in the deflected position in order to latch the coupling disc. The latching pawl is connected to the coupling disc via two spring sections, which are formed on at least one spring element, wherein the spring sections each have a pawl-side end fixed to the latching pawl and a coupling disc-side end fixed to the coupling disc. Therefore, according to the invention, the latching pawl is suspended on the coupling disc via the two spring sections and is not plugged onto a bearing pin with a predetermined fixed axis of rotation as is conventional. This eliminates the usual bearing play and the noise associated therewith.

[0007] For the sensitive introduction of the safety belt into the locking of the belt reel, the mass inertia of the locking pawl is utilized. If the belt reel is subjected to a torque due to the sudden withdrawal of the safety belt, the locking pawl lags behind the rotation of the coupling disc together with the belt reel due to its inertia. As a result, the locking pawl is pivoted relative to the coupling disc into its deflected position, in which the locking pawl engages with the locked end in a locking engagement on the frame of the belt retractor and thereby prevents the coupling disc from rotating further, so that the entire coupling disc is restrained relative to the belt reel.

[0008] A locking pawl is usually provided on the belt reel, which engages in a further locking engagement formed on the frame in a deflected position and locks the belt reel, wherein the belt reel and the locking pawl are preferably coupled via a control guide, and when the belt reel rotates relative to the coupling disc, the locking pawl is moved into its deflected position via the control guide.

[0009] The locking engagement on the coupling disc, into which the locking pawl can engage, and the locking engagement on the belt reel, into which the locking pawl can engage, are usually spaced a short distance apart from one another in the axial direction. The locking pawl does not have to withstand high forces, since the locking forces for restraining the belt reel are absorbed solely by the locking pawl on the belt reel.

[0010] If the tension of the belt belt decreases, the coupling disk can be pivoted relative to the belt reel in a known manner by the force of the return spring, wherein the blocking pawl and the latching pawl are pivoted back into their initial position.

[0011] The locking pawl is preferably fixed to the coupling disc only via the spring section. Where possible, there is a spacing between the flat side of the locking pawl facing the coupling disc and the coupling disc, so that the flat side of the locking pawl preferably does not contact the coupling disc. This reduces the friction effect between the locking pawl and the coupling disc, which further reduces the generation of noise. A further advantage is that the reproducibility of the pivoting movement of the locking pawl can be improved by the reduced friction. It has been shown that, in addition to the two spring sections, the locking pawl does not require an additional support. Therefore, it is also possible to avoid contact between the locking pawl and other areas of the coupling disc, which also reduces the generation of noise.

[0012] Preferably, a single spring element is provided, which has two spring sections. Here, the spring sections are particularly configured in a linked manner, wherein the spring element is fixed to the coupling disk in the middle section, and its two free ends form the two spring sections.

[0013] As an alternative, it is of course also possible to use exactly two separate spring elements, each of which has one of the spring sections, wherein preferably each of the spring elements consists only of this spring section.

[0014] Generally, the spring element should be fixed on the coupling disk in an immovable manner relative to the coupling disk. The two ends of the spring section on the coupling disk side are also usually fixed on the coupling disk in an immovable manner.

[0015] The spring element can be arranged, for example, in such a way that the end of at least one spring section on the coupling disk side is fixed to the coupling disk in the region of the center of gravity and / or (virtual) pivot point of the latching pawl. In this way, the virtual pivot point of the latching pawl can be predetermined, for example, approximately in the center region of the latching pawl, optionally in the vicinity of the center of gravity of the latching pawl during its pivoting movement, which has been shown to be advantageous for the pivoting movement.

[0016] In this case, the ends of the two spring sections on the coupling disk side can be fixed at a distance from one another on the coupling disk in order to determine, for example, a virtual rotation point on the surface of the latching pawl.

[0017] In a preferred variant, the pawl-side end of the spring section is fixed in the region of the two free ends of the latching pawl. In this way, a high degree of deflection of the spring section and thus also sufficient restoring force to move the latching pawl back into its initial position can be achieved when the latching pawl is pivoted.

[0018] In a further preferred variant, the pawl-side end of one spring section is fixed in the region of one of the free ends of the latching pawl, while the pawl-side end of the second section is fixed in the middle region of the latching pawl. In this case, the spring action is always applied only to one end of the latching pawl, which allows the relevant spring section to be designed with a higher torsional rigidity, which results in a more stable connection overall between the latching pawl and the coupling disk.

[0019] Generally speaking, the positioning of the ends of the two spring sections on the pawl side and the ends on the coupling disk side on the locking pawl and on the coupling disk is determined by a person skilled in the art. By changing the positions, the virtual pivot point of the locking pawl and the control curve of the locking end of the locking pawl can generally be influenced to a large extent. In this case, the control movement of the locking pawl is not limited by the pivot bearing, so that, for example, a linear or S-shaped control curve can also be realized. This gives a person skilled in the art great flexibility in designing the locking function of the locking pawl.

[0020] A further degree of freedom for a person skilled in the art is to adjust the spring constants of the two spring sections. The spring constants can be selected differently, which likewise enables an influence on the control curve, but of course also influences the restoring force acting on the latching pawl. However, it may also be advantageous to select the spring constants of the two spring sections to be identical.

[0021] The two spring sections preferably extend at approximately a 90° angle to one another. This arrangement has been shown to be advantageous for obtaining a torque of the latching pawl. The latching pawl can have a curved shape, wherein its radially inner sides can enclose an angle of approximately 90°, which can simplify the realization of the 90° angle between the spring sections.

[0022] The at least one spring element is preferably designed as a leaf spring. In addition to the advantage of being able to be arranged cost-effectively and space-savingly, the leaf spring also has a high torsional rigidity. As a result, a reliable axial stop of the latching pawl can be easily achieved. In addition, the leaf spring can be easily preformed, so that the installation effort of the spring element on the coupling disk can be kept low. Of course, it is also conceivable, for example, to design only the spring section as a leaf spring, while the middle section of the spring element is realized in another way.

[0023] The at least one spring element is preferably arranged so that it provides a restoring force that loads the latching pawl force into the initial position, thereby preventing an unexpected deflection of the latching pawl and moving the latching pawl back to its normal position again when the locking condition on the safety belt side is reduced.

[0024] The coupling disc advantageously has one or more stops against which the latching pawl abuts in its initial position or in its deflected position. The movement clearance of the latching pawl can thus be limited in a simple manner. In the initial position, the latching pawl can be held pressed against one of the stops by the return force of the spring element, which prevents unintended movement of the latching pawl and thus further reduces the generation of noise. In the deflected position, the abutment of the latching pawl on at least one other stop assists the load transfer to the coupling disc, so that the latching pawl is locked between the stop and the locking engagement in its deflected position.

[0025] The stop can be designed, for example, as an axially protruding projection in the coupling disk and can be produced in one piece with the coupling disk.

[0026] It is possible to design the stop to be sound-absorbing, for example by means of a suitable elastic material, so that the contact of the latching pawl on the stop does not generate any noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be described in more detail below based on multiple embodiments with reference to the accompanying drawings. The accompanying drawings are as follows:

[0028] - Figure 1 A schematic perspective view of a seat belt retractor according to the invention according to a first embodiment is shown, wherein the locking side of the seat belt retractor is exposed;

[0029] - Figure 2 Show Figure 1 A schematic side view of a seat belt retractor in FIG.

[0030] - Figure 3 Show Figure 1 A sectional view of the seat belt retractor at the height of the locking engagement of the locking pawl, wherein the locking pawl is in its initial position;

[0031] - Figure 4 Show Figure 3 A seat belt retractor in which the locking pawl is in its deflected position;

[0032] - Figure 5 Show Figure 3 Detailed view of the seat belt retractor in;

[0033] - Figure 6 Show Figure 4 Detailed view of the seat belt retractor in;

[0034] - Figure 7A schematic diagram of a coupling disc of a belt retractor according to the invention according to a second embodiment is shown, wherein the latching pawl is shown both in its initial position and in its deflected position; and

[0035] - Figure 8 A schematic diagram of a coupling disk of a belt retractor according to the invention is shown according to a third specific embodiment, wherein the latching pawl is shown both in its initial position and in its deflected position. DETAILED DESCRIPTION

[0036] Figure 1 A belt retractor 10 of a vehicle belt system (not shown in detail) according to a first embodiment is shown. The belt retractor 10 has a frame 12 in which a belt reel 14 is rotatably mounted, on which a seat belt (not shown) is wound, which is wound around the belt reel 14 and can be pulled out from the belt reel in a belt pull-out direction R.

[0037] On the locking side 16 of the seat belt retractor 10 ( Figure 1 ), the belt reel 14 has a locking pawl (not shown) which, in a deflected position, engages in a first locking engagement 18 which is formed directly on the frame 12 and thus locks the belt reel 14 .

[0038] A coupling disc 20 is arranged outwardly following the belt reel 14 in the axial direction A of the belt reel 14 and is connected to the belt reel 14 in such a way that it can be rotated to a predetermined extent relative to the belt reel 14. A return spring (not shown) connects the coupling disc 20 to the belt reel 14 and loads the coupling disc 20 in the direction of its initial position.

[0039] A locking toothing 22 is formed on the outer circumference of the coupling disk 20 , via which the coupling disk 20 is locked in rotation by a vehicle-sensitive latching unit and can thus be restrained relative to the belt reel 14 , which can be designed in a known manner and is not shown in detail here.

[0040] On the side of the coupling disk 20 facing away from the belt reel 14, a latching pawl 24 is provided, which has two free ends 26, 28. One of the two free ends 26, 28 (here, the end 26) is designed as a locking end and is released when the latching pawl 24 is moved from its initial position (see Figure 3 ) pivots to its deflected position (see Figure 4 ) is embedded in the second locking engagement portion 30.

[0041] The blocking toothing 30 surrounds the coupling disk 20 in the circumferential direction and is arranged in the axial direction A adjacent to the first blocking toothing 18 , wherein the blocking toothing 30 is formed on a component 32 which is connected to the frame 12 of the belt reel 10 .

[0042] The latching pawl 24 acts as an inertia element. If a sudden torque acts on the belt reel 14 due to a sudden pulling of the belt in the belt withdrawal direction R, the latching pawl 24 lags behind the coupling disc 20, which is still rotating with the belt reel 14. This relative rotation between the latching pawl 24 and the coupling disc 20 causes the latching pawl 24 to pivot out into a deflected position in which its locking end engages in the second locking engagement 30. Since the latching pawl 24 is fixed to the coupling disc 20, a further rotation of the coupling disc 20 is now also prevented.

[0043] The coupling disc 20 and the belt reel 14 are coupled to each other via a control guide 34, which is realized here by a guideway guide 36 in the coupling disc and a guide pin 38 guided in the guideway guide 36 and connected to the locking pawl of the belt reel 14. If the coupling disc 20 is now retained on the second locking toothing 30 (at this point in time Figure 4 ), then in the next step the belt reel 14 is rotated relative to the coupling disc 20, wherein the guide pin 38 is moved in the slotted guide 36, which causes the locking pawl to pivot out and engage in the first locking engagement 18. From this point in time, the belt reel 14 is locked.

[0044] The latching pawl 24 is fixed to the coupling disk 20 only via the two spring sections 42, 44 of the spring element 40. In the present example, the spring element 40 is designed as a single, conventional leaf spring, the two free ends of which form the spring sections 42, 44. Figure 5 and Figure 6 ), the spring element 40 is fixedly connected to the coupling disk 20. In the present example, the middle section 46 is injection-molded with the material of the coupling disk 20.

[0045] The spring constants of the two spring sections 42 , 44 can be selected to be different or identical.

[0046] Each of the two spring sections 42, 44 has a pawl-side end 48a, 48b, which is respectively fastened to the latching pawl 24. In addition, each spring section 42, 44 has a coupling disk-side end 50a, 50b, which is fastened to the coupling disk 20 and which in this example each transitions into the middle section 46 of the spring element 40. The exact position of the respective coupling disk-side ends 50a, 50b and their spacing is determined by the fixed width of the middle section 46.

[0047] By being suspended on the two spring sections 42 , 44 , the position of the rotation point and the position of the center of gravity on the surface of the coupling disk 20 can also be shifted during the movement of the latching pawl 24 from the initial position into the deflected position.

[0048] The torsional stiffness of spring element 40 and in particular spring sections 42 , 44 is selected such that the flat side of latching pawl 24 facing coupling disk 20 is at least in the initial position at a small axial distance from the surface of coupling disk 20 , so that it substantially does not contact coupling disk 20 .

[0049] The latching pawl 24 has a curved shape in this example, wherein its radially inner side surfaces 52, 54 approximately enclose an angle of 90 °. In the initial position, the two spring sections 42, 44 are approximately parallel to the side surfaces 52, 54, so that the spring sections 42, 44 are also approximately oriented at an angle of 90 ° to each other.

[0050] At their radially inner ends, the two side faces 52, 54 transition into a recess 56 in the latching pawl 24. In this region, the center section 46 of the spring element 40 is fixed to the coupling disk 20, wherein in this example the center section is approximately in the region of the center of gravity of the latching pawl 24 in its initial position.

[0051] In the present embodiment, the pawl-side ends 48 a , 48 b of the two spring sections 42 , 44 are fastened directly to the free ends 26 , 28 , more precisely to the radially outer ends of the inner sides 52 , 54 of the latching pawl 24 .

[0052] Both the pawl-side ends 48 a , 48 b and the coupling disk-side ends 50 a , 50 b of the spring sections 42 , 44 are fixed in such a way that they are neither movable relative to the latching pawl 24 nor relative to the coupling disk 20 .

[0053] In general, the control movement of the latching pawl 24 can be defined in all the embodiments described by providing in a separate framework the fixing points of the latching ends 48a, 48b and the clutch-side ends 50a, 50b of the spring sections 42, 44 and the spring constants of the spring sections 42, 44. As a result, the control curve of the latching pawl 24 can also be adjusted very flexibly, and a linear or S-shaped control curve of the locking-side free end 26 of the latching pawl 24 can also be realized.

[0054] A plurality of stoppers 58 , 60 , 62 projecting in the axial direction A are provided on the surface of the coupling disk 20 oriented toward the latching pawl 24 and serve to prevent a further rotation of the latching pawl 24 in the initial position or in the deflected position.

[0055] The stop 58 is arranged here so that when the latching pawl 24 is in its initial position, it is located at the free end of the inner side 52 in the fixing area of ​​the pawl-side end 48a of the spring section 42. In the initial position, the latching pawl 24 rests on the stop 58 under the preload force of the spring element 40. In the present example, the latching pawl 24 does not contact the stops 60, 62 in the initial position.

[0056] In the deflected position, the latching pawl 24 is held in the load direction between stops 60, 62, which are respectively located in the region of the free ends 26, 28 of the latching pawl 24 (in the deflected position of the latching pawl). If the coupling disk 20 rotates relative to the belt reel 14 and thus does not have to absorb a part of this load, the spring sections 42, 44 are thus unloaded.

[0057] As in Figures 3 to 6 As can be clearly seen in FIG, if the latching pawl 24 is pivoted into the deflected position, the spring sections 42, 44 are bent. This generates a restoring force which acts in the direction of the initial position of the latching pawl 24 and causes the latching pawl 24 to return to the initial position when the tensile stress on the seat belt is reduced.

[0058] In the present example, the latching pawl 24 is in contact with the coupling disk 20 only via the two spring sections 42 , 44 and the stops 58 and 60 , 62 .

[0059] The contact surfaces of the stops 58 , 60 , 62 can be designed to be sound-damping, for example by having a coating with a sound-damping material or by the stops being composed completely or partially of such a material.

[0060] Figure 7A second embodiment is shown, in which only the shape of the latching pawl 124 and the arrangement of the spring sections 142, 144 on the coupling disk 20 are changed compared to the first embodiment. All other components of the belt retractor 10 are identical to those of the first embodiment and are not shown or described again here.

[0061] exist Figure 7 1 shows the latching pawl 124 and the spring sections 142 , 144 both in the initial position (thin line) and also in the deflected position (solid line). In each case, only a single latching pawl 124 and a spring section 142 , 144 are provided.

[0062] In the present example, the spring sections 142 , 144 are shown as independent spring elements, but they can also be connected to the ends 150 a , 150 b on the coupling disk side as in the first embodiment.

[0063] As in the first embodiment, the pawl-side ends 148a, 148b of the two spring sections 142, 144 are fixed to radially outer ends of inner sides 152, 154 of the latching pawl 124, while the coupling disk-side ends 150a, 150b are connected to the coupling disk 20 in the area of ​​the center of gravity of the latching pawl 24. The virtual pivot point of the latching pawl 124 is also in this area.

[0064] Figure 8 A third embodiment is shown. Figure 7 As in , here too, the latching pawl 224 is shown both in the initial position (dashed line) and in the deflected position (solid line).

[0065] Unlike the two above embodiments, the pawl-side end 248b of the spring element 244 is not fixed to the free end 228 of the latching pawl 224, but is fixed in the region of the radially inner end of the inner side 254. The fixing point of the spring section 242 is here in the region of the recess 256 on the latching pawl 224.

[0066] As in the previous embodiment, the pawl-side end 248 a of the spring portion 242 is then fixed in the region of the free locking end 226 on the inner side 252 of the latching pawl 224 .

[0067] This arrangement results in that essentially only one spring section 242, 244 is deflected when the latching pawl 224 is pivoted, namely the spring section on the locking-side free end 226 of the latching pawl 224. This allows the two spring sections 242, 244 to be designed with a stronger connection than in the previous embodiment.

Claims

1. A seat belt retractor (10) for a vehicle seat belt system, the seat belt retractor comprising a frame (12) and a seat belt reel (14) mounted in the frame (12), the seat belt reel being connected to a coupling disc (20) which can be rotated relative to the seat belt reel (14) by a predetermined degree, wherein: A locking pawl (24; 124; 224) is arranged on the coupling disk (20) so as to be radially deflectable from an initial position, and the locking pawl engages in a locking engagement portion (30) fixed to the frame in the deflected position to lock the coupling disk (20), wherein the locking pawl (24; 124; 224) is connected to the coupling disk (20) via two spring sections (42, 44; 142, 144; 242, 244), which constitute The invention relates to a spring element (40) and a spring member (50a, 50b, 150a, 150b, 250a, 250b) which is formed on at least one spring element (40), wherein the two spring sections (42, 44; 142, 144; 242, 244) each have a pawl-side end (48a, 48b; 148a, 148b; 248a, 248b) fixed to a locking pawl (24; 124; 224) and a coupling disk-side end (50a, 50b; 150a, 150b; 250a, 250b) fixed to a coupling disk (20).

2. The seat belt retractor according to claim 1, characterized in that: A locking pawl is provided on the belt reel (14), which engages in a locking engagement portion (18) formed on the frame (12) in a deflected position and locks the belt reel (14), wherein the coupling disc (20) and the locking pawl are coupled via a control guide (34), and when the belt reel (14) rotates relative to the coupling disc (20), the locking pawl is moved to its deflected position via the control guide.

3. The seat belt retractor according to claim 1, characterized in that: The latching pawl (24; 124; 224) is fixed to the coupling disk (20) only via the spring section (42, 44; 142, 144; 242, 244).

4. The seat belt retractor according to any one of claims 1 to 3, characterized in that: A single spring element (40) is provided which has two spring sections (42, 44; 142, 144; 242, 244).

5. The seat belt retractor according to any one of claims 1 to 3, characterized in that: The coupling disk-side end (50a, 50b; 150a, 150b; 250a, 250b) of at least one spring section (42, 44; 142, 144; 242, 244) is fixed to the coupling disk (20) in the region of the center of gravity and / or virtual rotation point of the locking pawl (24; 124; 224).

6. The seat belt retractor according to any one of claims 1 to 3, characterized in that: The latching pawl has two free ends (26, 28; 126, 128) and a pawl-side end of a spring section is fixed in the region of each free end (26, 28; 126, 128).

7. The seat belt retractor according to any one of claims 1 to 3, characterized in that: The detent pawl has two free ends, and the pawl-side end of a spring section is fixed in the region of one of the free ends, while the pawl-side end of the second spring section is fixed in the middle region of the detent pawl.

8. The seat belt retractor according to any one of claims 1 to 3, characterized in that: The spring constants of the two spring sections (42, 44; 142, 144; 242, 244) are different.

9. The seat belt retractor according to any one of claims 1 to 3, characterized in that: The two spring sections (42, 44; 142, 144; 242, 244) extend at an angle of 90° to one another.

10. The seat belt retractor according to any one of claims 1 to 3, characterized in that: The at least one spring element (40) is a leaf spring.

11. The seat belt retractor according to claim 10, characterized in that: The spring sections (42, 44; 142, 144; 242, 244) are designed as leaf springs.

12. The seat belt retractor according to any one of claims 1 to 3, characterized in that: The at least one spring element (40) is arranged in such a way that it provides a restoring force which loads the latching pawl (24; 124; 224) into an initial position.

13. The seat belt retractor according to any one of claims 1 to 3, characterized in that: At least one of the spring sections (42, 44; 142, 144; 242, 244) is arranged such that it provides a restoring force which loads the latching pawl (24; 124; 224) into an initial position.

14. The seat belt retractor according to any one of claims 1 to 3, characterized in that: The coupling disk (20) has one or more stop portions (58, 60, 62) against which the latching pawl (24; 124; 224) abuts in its initial position or in its deflected position.

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