Self-locking belt retractor

Abstract

The invention relates to a self-locking belt retractor having a belt winding shaft (1) rotatably mounted in a frame (2) which can be attached to the vehicle, and having a blocking system (3) for the belt winding shaft (1), which system is at least vehicle-sensitively controlled and in which, when triggered, a vehicle-sensitively mounted sensor mass (5) moves a locking lever, by means of its engagement tip in engagement with teeth (9) of a control disc (4), into a triggered position, wherein the sensor mass (5) is arranged in a supporting part (6) on a support surface and, when vehicle accelerations occur in the supporting part (6), can be moved in an inertia-controlled manner on the support surface from a neutral position into the triggered position, wherein the supporting part (6) having the sensor mass (5) arranged therein is arranged in a housing (11) which surrounds the control disc (4) and has first ring teeth (13), wherein an attachment ring (12) having second ring teeth (14) is provided, wherein the attachment ring (12) has at least one first attachment projection (16) by means of which it is attached to the frame (2) of the belt retractor, and the attachment ring (12) has at least one second attachment projection (17) to which the housing (11) is attached by means of engagement of the first ring teeth (13) in the second ring teeth (14).

Description

[0001] Self-locking belt retractor

[0002] The invention relates to a self-locking belt retractor with a blocking system for a belt winding shaft that can be controlled at least in a vehicle-sensitive manner, in which, in the event of triggering, a vehicle-sensitively mounted sensor mass moves a locking lever with its engagement tip into engagement with the toothing of a control disc into a triggering position, whereby the control disc is stopped in its common rotational movement with the belt winding shaft and the blocking system is activated, wherein the sensor mass is arranged on a support surface of a carrier part and, when vehicle acceleration occurs, can be moved on the support surface of the carrier part in an inertia-controlled manner from a neutral position into the triggering position, wherein the carrier part with the sensor mass arranged therein is arranged in a housing enclosing the control disc.

[0003] A belt retractor with the aforementioned features is described in DE 195 39 619 C2. The locking lever is positively connected to a sensor mass at the end opposite the engagement tip, forming a support. The sensor mass, in turn, is pivotally mounted on a support surface.

[0004] A general problem with such belt retractors is that, in order to function properly, the sensor mass must be arranged in a specific spatial orientation and in relation to the support surface so that it is reliably only moved from the neutral position to the trigger position when the specified vehicle deceleration limit is exceeded. The orientation of the sensor mass and the support surface also depend on the installation position of the belt retractor in the vehicle, which is determined by the body structure and the intended mounting location on the vehicle. This means that the sensor and the support surface must be individually aligned with the belt retractor for the specific installation position of the belt retractor in the vehicle so that the sensor mass and the support surface have the spatial orientation and in relation to the vehicle that is important for their function.

[0005] For this purpose, it is known from WO 2009 / 143984 A1 to provide an annular toothing on the inside of a sensor cap that covers the sensor on the outside, in which the sensor can be held at various angular orientations relative to the control disc. The annular toothing on the sensor cap creates a fastening attachment on which the sensor, with the sensor mass and the support surface, can be arranged in various orientations and arrangements relative to the control disc without the need for structural modifications to the belt retractor. For this purpose, a complementary toothing is also provided on the sensor, with which the sensor is pressed into the toothing of the sensor cap at a predetermined angular orientation. The sensor is then fixed in the circumferential direction by the positive engagement of the toothing.The sensor cap with the sensor arranged in it is then attached to the frame of the belt retractor so that the sensor is then securely clamped between the sensor cap and the frame of the belt retractor.

[0006] Furthermore, a belt retractor is known from the document DE 10 2016 202 383 B4, in which the sensor cap, referred to therein as the housing, has a first annular toothing on its radially outer edge, which is arranged on the side facing away from the frame. Furthermore, a fastening ring with a second toothing is provided, which is placed on the outside and thus fixes the housing and the sensor cap in a fixed position by the engagement of the toothings in a defined orientation. The housing is thus fastened by first arranging and holding it in a defined orientation, and the fastening ring is then placed on such that its toothing engages with the toothing of the housing and is subsequently fastened. Fastening the housing therefore requires aligning the housing and holding the housing in the defined orientation, without the housing being fixed during this phase.If, for example, the housing slips or twists slightly after alignment and while being held, the housing will not be fixed in the defined orientation but in the twisted orientation. This represents a source of error that can only be eliminated by increasing the manufacturing effort.

[0007] The object of the invention is to provide an improved self-locking belt retractor in which the alignment of the sensor to the control disc can be adjusted with simplified means and with high precision during the assembly process. The invention solves this problem with the features of independent claim 1. Further advantageous embodiments of the invention can be found in the dependent claims, the figures, and the associated description.

[0008] According to the basic idea of ​​the invention, it is proposed that the fastening ring has at least one first fastening lug with which it is fastened to the frame of the belt retractor, and the fastening ring has at least one second fastening lug to which the housing is fastened with an engagement of the first ring toothing in the second ring toothing.

[0009] The proposed solution differs fundamentally from the prior art solution in that the fastening ring is first fastened to the frame via the first fastening projection and itself forms the holder for the housing via the second fastening projection. This means that the housing is no longer placed in the predetermined orientation and then secured by the fastening ring, as in the prior art, but instead the fastening ring is first fastened and the housing is then aligned in the predetermined orientation and fastened to the fastening ring. This means that the housing is aligned and fastened in a single step and no longer needs to be fixed in the aligned position until it is secured by the fastening ring. The proposed solution thus enables a significantly simplified assembly process with a reduced probability of errors in the alignment of the housing.

[0010] It is further proposed that the second fastening projection be formed by an annular, radially projecting collar, and that the housing have one or more locking edges with which the housing is positively locked to the collar. By designing the second fastening projection as an annular collar, the housing can be fastened to the fastening projection and thus to the belt retractor at any rotational angle. Furthermore, due to its closed design, the annular collar forms a particularly dimensionally stable fastening projection and thus a particularly strong mount for the housing.

[0011] It is further proposed that the housing have a first annular wall enclosing the fastening ring and having a plurality of recesses, and that the locking edges are formed by radially inwardly directed projections of the first annular wall in the region of the recesses. When the housing is placed on, the annular wall essentially forms a type of guide, which simplifies sliding on, aligning in the predetermined rotational angle position and finally the final fastening process, i.e. locking onto the annular collar. Furthermore, recesses are provided in the annular wall, on which the locking edges are formed by radially inwardly directed projections, which form the counter surface for the locking. Due to the recesses, the locking edges can be integrally molded onto the housing in an injection molding process.Furthermore, the recesses weaken the ring wall slightly in the area of ​​the locking edges so that the housing can more easily carry out the spring movements required for locking in these areas of the ring wall.

[0012] It is further proposed that the housing have a second annular wall, which defines an annular space adjacent to the first annular wall, into which the fastening ring with the first annular toothing extends. The second annular wall further improves the guidance of the housing when placed on the fastening ring. Furthermore, the second annular wall forms an additional radially inner stop surface for the housing, which limits any possible radial movement of the housing relative to the fastening ring.

[0013] It is further proposed that the first and second ring gears be formed by spur gears directed axially in the fastening direction of the housing. The proposed design of the two ring gears simplifies the engagement movement relative to the fastening direction of the housing to the frame, i.e., relative to the sliding movement of the housing. Due to the proposed design of the ring gears, they first engage the tips of the tooth flanks on the front side during the sliding movement and then automatically align themselves with each other during the subsequent increasing meshing until the tooth flanks are in flat contact with one another.

[0014] It is further proposed that the first and / or second ring gears be laterally delimited by a boundary wall toward the radial inner side and / or the radial outer side. The lateral limitation of the ring gear(s) secures the other ring gear(s) against lateral slippage, and the ring gears are thereby radially fixed to one another.

[0015] The first ring gear and the second ring gear can preferably each be laterally delimited by a boundary wall, wherein the boundary walls are preferably arranged on different sides of the ring gears. This fixes the ring gears to each other both on the radial inner side and the radial outer side.

[0016] The invention will be explained below using preferred embodiments with reference to the attached figures.

[0017] Fig. 1: a self-locking belt retractor with a blocking system with a sensor mass without a housing; and

[0018] Fig. 2: the housing as a single part in different views; and

[0019] Fig. 3: a fastening ring with the housing;

[0020] Fig. 4: an enlarged section of the fastening ring with and without housing in different sectional views.

[0021] Figure 1 shows a self-locking belt retractor according to the invention, comprising a frame 2 that can be fixedly mounted to the vehicle and a belt winding shaft 1 rotatably mounted in the frame 2. A safety belt (not shown) that serves to restrain a vehicle occupant can be wound onto the belt winding shaft 1. The belt winding shaft 1 is pretensioned in the winding direction by a torsion spring (not shown), so that the safety belt, when fastened, rests against the occupant with as little slack as possible and is securely wound into the parking position when unbuckled.

[0022] The belt retractor further comprises a blocking system 3 with a control disc 4 and a blocking pawl (not shown), which, when activated, retracts into a blocking toothing 19 of the frame and thereby blocks the belt take-up shaft 1 against further belt webbing withdrawal. The blocking system 3 further comprises a control disc 4 rotatably mounted on the belt take-up shaft 1, which is pretensioned in the unwinding direction relative to the belt take-up shaft 1 by a spring. A control contour is provided on the control disc 4, into which the blocking pawl (not shown) engages with a pin. In the event that the control disc 4 is stopped relative to the belt take-up shaft 1 during the withdrawal movement of the seat belt, the control disc 4 forces a control movement of the blocking pawl into the blocking toothing 19, whereby the belt take-up shaft 1 is blocked in the belt webbing withdrawal direction.

[0023] The blocking system 3 further comprises a sensor mass 5, which here is designed as a standing mushroom mass, and a support part 6. The support part 6 has a support surface on which the sensor mass 5 stands. The blocking system 3 also has a locking lever against which the sensor mass 5 rests. If the sensor mass 5 is pivoted from a neutral position into a triggering position due to a vehicle deceleration exceeding the predetermined limit value, the locking lever is deflected far enough that its engagement tip engages the toothing 9 of the control disc 4, whereby the control disc 4 is stopped relative to the belt take-up shaft 1 to trigger the blocking.Furthermore, an inertial mass (not shown in detail) is arranged on the control disc 4, which is spring-loaded in the winding direction relative to the control disc 4 and, when a predetermined limit value of the belt webbing withdrawal acceleration is exceeded, is deflected relative to the control disc 4 and engages with a WS toothing of the housing, thereby stopping the control disc 4 relative to the belt winding shaft 1. In order for the sensor with the sensor mass 5 and the carrier part 6 to only block the belt winding shaft 1 as intended when the predetermined limit value of the vehicle deceleration is exceeded, it is important that the sensor mass 5 is in the neutral position in a predetermined upright position in which the locking lever does not engage with the toothing 9 of the control disc 4, and the control disc 4 can rotate freely together with the belt winding shaft 1.In order for one and the same belt retractor to be used in as many vehicles as possible, in different installation orientations, the carrier part 6 and the sensor mass 5 held therein must be aligned on the belt retractor for each vehicle in such a way that the sensor mass 5 is in the neutral position in the respective installation position of the belt retractor below the specified vehicle deceleration so that the belt winding shaft 1 can rotate freely.

[0024] The belt retractor further comprises a housing 11 and a fastening ring 12, which can be seen in Figure 3. The housing 11 encloses the control disc 4 on the outside in the fastened position. The fastening ring 12 is attached to the frame 2 of the belt retractor and, in turn, serves to secure the housing 11.

[0025] The housing 11 can be seen in various views as an individual part in Figure 2. The housing 11 has a receptacle 15, which is shaped such that the carrier part 6 with the sensor mass 5 therein is arranged on the housing 11 in an exclusively predetermined orientation. For assembly, the subassembly comprising the carrier part 6 and the sensor mass 5 is inserted into the housing 11 and fixed. The housing 11 further has an axially aligned first annular wall 8 on its radial outer side, in which a plurality of window-shaped recesses 10 are provided.

[0026] The fastening ring 12, shown in Figure 3, has a plurality of first fastening projections 16, which protrude axially from the rear side of the fastening ring 12 and are arranged such that the fastening ring 12 can be fastened to the frame 2 in only one orientation in corresponding fastening openings 18. A first annular toothing 13 is provided on the front side of the fastening ring 12, which is delimited towards the radial outside by a boundary wall 23. The housing 11 has a second annular wall 20, shown in the lower illustration in Figure 4, which is arranged at a distance radially inward from the first annular wall 8 and delimits an annular space 21 from the first annular wall 8. A second annular toothing 14, which can also be seen in Figure 2 through the recesses 10, is arranged on the second annular wall 20 in the base of the annular space 21.The second annular wall 20 thus forms a radially inner boundary wall 22 for the second annular toothing 14. The first and second annular toothings 13 and 14 are ring-shaped as spur gears with axially directed teeth and are arranged such that, in the fastened position on the belt retractor, they are aligned concentrically with the axis of rotation of the belt take-up shaft 1. Due to their design as spur gears, the annular toothings 13 and 14 first engage with the tooth tips when the housing 11 is placed on the fastening ring 12 and then automatically align themselves with one another during the further placement movement until they lie flat against one another. Their movement relative to one another is limited radially inward by the boundary wall 22 of the second annular wall 20 and radially outward by the boundary wall 23 of the fastening ring 12.Thus, the housing 11 is defined in its radial orientation both towards the radial inside and the radial outside and is limited in terms of movement.

[0027] The fastening ring 12 is first attached to the frame 2 via the first fastening projections 16 and then protrudes from the frame 2 with the first ring gears 13. The fastening ring 12 further has a second fastening projection 17 in the form of an annular protruding collar on its radial outer side. The collar has a conical shape with a diameter that increases in the fastening position toward the frame 2 or toward the first fastening projections 16.

[0028] In the region of the recesses 10, the housing 11 has locking edges 7 in the form of radially inwardly directed projections, which are formed by a thickening of the edge sides of the recesses 10 facing the free edge of the first annular wall 8. The locking edges 7 are conical in shape with a wall thickness that decreases towards the free edge of the first annular wall 8, so that the inner diameter of the housing 11 increases in this region towards the free side of the first annular wall 8. The locking edges 7 are deliberately provided in the region of the recesses 10 so that the housing 11 can be manufactured as a one-piece plastic part in a single injection molding process as a mass-produced part. Furthermore, the housing 11 is deliberately weakened in the region of the locking edges 7 by the recesses 10 so that it can perform the locking movement, explained in more detail below, when attached to the fastening ring 12 in a simplified manner.

[0029] To attach the housing 11, the fastening ring 12 is first attached to the frame 2 via the first fastening projections 16. The fastening ring 12 then forms a separate fastening projection for the housing 11 with its annular collar as the second fastening projection 17. The housing 11 is then pre-assembled with the sensor and placed on the fastening ring 12 in a predefined rotational angle orientation by sliding it onto the fastening ring 12 with the annular space 21. In this process, the housing 11 comes to rest with the conical inner sides 25 under the recesses 10 against the conical outer side 24 of the second fastening projection 17 formed by the annular, protruding collar.During the further sliding movement of the housing 11, the housing 11 is deformed slightly outwards in the area of ​​the projections 7, and the fastening ring 12 is deformed slightly inwards in these areas until the housing 11, with the projections 7, locks behind the second fastening attachment 17 in the position shown in the middle illustration in Figure 4. The middle illustration in Figure 4 shows a sectional view of a detail through the housing 11 and the fastening ring 12 in the area of ​​the cutouts 10 of the housing 11. The lower illustration in Figure 4 shows a sectional view through a detail of the housing 11 and the fastening ring 12 between the recesses 10 in the area of ​​the intermeshing first ring toothing 13 and second ring toothing 14.The housing 11 is pushed on and secured by the fastening on the second fastening projection 17 to such an extent that the first ring gear 13 engages with the second ring gear 14, so that the housing 11 is fixed in its rotational angular position relative to the fastening ring 12. Furthermore, the housing 11 is supported with the inside of the first ring wall 8 on the outside of the second fastening projection 17 formed by the collar, so that it is also fixed in this direction.

[0030] The fastening ring 12 is arranged in the fastening position between the frame 2 and the housing 11 and forms a holder for the housing 11 with the second fastening projection 17.

[0031] The second fastening projection 17 on the fastening ring 12 is deliberately designed as an annular, preferably closed collar, so that the housing 11 can be fastened to the fastening ring 12 in a variety of positions, preferably at any desired angle of rotation. Furthermore, this improves the sealing of the belt retractor with respect to the ingress of foreign bodies or dust particles, in that the housing 11 forms a type of labyrinth seal with the fastening ring 12.

[0032] The sensor is inserted into the housing 11 prior to assembly and is then protected by the housing 11 during the fastening process to the belt retractor. The alignment of the housing 11 in the predetermined rotational angle position can then be performed in rotational angle steps determined by the tooth spacing of the toothings 13 and 14. Thus, the finer the toothings 13 and 14, the finer the adjustability of the sensor's rotational angle relative to the rotational axis of the belt retractor shaft 1.

[0033] The fastening ring 12 is arranged in the fastening position between the frame 2 and the housing 11 and, together with the second fastening projection 17, forms a holder for the housing 11 with a positive fastening or locking mechanism.

Claims

Claims:

1. Self-locking belt retractor with -a belt winding shaft (1) rotatably mounted in a frame (2) which can be fixed to the vehicle, and -a blocking system (3) for the belt winding shaft (1) which is controlled at least in a vehicle-sensitive manner and in which, in the event of triggering, a sensor mass (5) mounted in a vehicle-sensitive manner moves a locking lever with its engagement tip into engagement with a toothing (9) of a control disc (4) into a triggering position, whereby the control disc (4) is stopped in its common rotational movement with the belt winding shaft (1) and the blocking system (3) is activated, wherein -the sensor mass (5) is arranged in a carrier part (6) on a support surface and can be moved inertially controlled from a neutral position into the triggering position in the carrier part (6) on the support surface when vehicle accelerations occur, wherein -the carrier part (6) with the sensor mass (5) arranged therein is arranged in a housing (11) comprising the control disc (4) and having a first ring toothing (13), wherein -a fastening ring (12) with a second ring toothing (14) is provided, and -the housing (11) with the support part (6) and the sensor mass (5) arranged therein can be fastened to the belt retractor in different rotational angle positions relative to the control disc (4) by an engagement of the first ring toothing (13) in the second ring toothing (14) of the fastening ring (12), characterized in that -the fastening ring (12) has at least one first fastening lug (16) with which it is fastened to the frame (2) of the belt retractor, and -the fastening ring (12) has at least one second fastening projection (17) to which the housing (11) is fastened with an engagement of the first ring toothing (13) in the second ring toothing (14).

2. Self-locking belt retractor according to claim 1, characterized in that - the second fastening projection (17) is formed by an annular radially projecting collar, and -the housing (11) has one or more locking edges (7) with which the housing (11) is positively locked to the collar.

3. Self-locking belt retractor according to claim 2, characterized in that - the housing (11) has a first annular wall (8) comprising the fastening ring (12) with a plurality of recesses (10), and -the locking edges (7) are formed by radially inwardly directed projections of the first annular wall (8) in the region of the recesses (10).

4. Self-locking belt retractor according to claim 3, characterized in that - the housing (11) has a second annular wall (20) which delimits an annular space (21) to the first annular wall (8), into which the fastening ring (12) with the first annular toothing (13) projects.

5. Self-locking belt retractor according to one of claims 1 to 4, characterized -the first and second ring gears (13, 14) are formed by spur gears directed axially in the fastening direction of the housing (11).

6. Self-locking belt retractor according to claim 5, characterized in that -the first and / or second ring toothing (13, 14) are laterally delimited towards the radial inner side and / or towards the radial outer side by a boundary wall (22, 23).

7. Self-locking belt retractor according to claim 6, characterized in that -the first ring toothing (13) and the second ring toothing (14) are each laterally delimited by a boundary wall (22, 23), and -the boundary walls (22,23) on different sides of the ring gears (13,14) are arranged.

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