Self-locking belt retractor

Abstract

The invention relates to a self-locking belt retractor (11) comprising a belt shaft (13) rotatably mounted in a frame (12), the belt shaft (13) being capable of winding up a safety belt on said belt shaft, a blocking device for blocking the belt shaft (13) in the unwinding direction of the safety belt if a predefined unwinding acceleration of the safety belt is exceeded, and a control disk device (1) mounted on the belt shaft (13), the control disk device (1) comprising a control disk (2) and an inertial mass body (3) mounted on the control disk (2) so as to be pivotable about a pivot axis (4).

Description

[Technical field]

[0001] The invention relates to a self-locking belt retractor having a belt shaft rotatably mounted in a frame and capable of winding up a safety belt, a blocking device blocking the belt shaft in the unwinding direction of the safety belt when a predefined unwinding acceleration of the safety belt is exceeded, and a control disk device mounted on the belt shaft and spring-loaded in particular in the extension direction of the safety belt, the control disk device comprising a control disk and an inertial mass mounted on the control disk so as to pivot about a pivot axis, the (virtual) pivot axis of the inertial mass being in particular aligned parallel to the rotation axis of the belt shaft.

[0002] Self-locking belt retractors are commonly used in vehicle safety belt systems to retract an unfastened safety belt into a parking position and to allow variable extension of the safety belt with as little slack as possible. For this purpose, the belt retractor is rotatably mounted in a frame and has a belt shaft spring-loaded in the winding direction, on which the safety belt can be wound. The belt retractor further has a blocking device which is activated when a predetermined unwinding acceleration of the safety belt is exceeded, whereby the belt shaft is subsequently blocked in the belt unwinding direction. The blocking device comprises a blocking claw mounted on the belt shaft, the movement of which is controlled by a control disk device rotatably mounted on the belt shaft. A control disk of the control disk device is spring-loaded in the belt unwinding direction of the belt shaft and rotates together with the belt shaft below a predetermined unwinding acceleration of the safety belt. An inertial mass is pivotally mounted on the control disk, which pivots when a predetermined unwinding acceleration of the safety belt is exceeded, thereby engaging teeth mounted on the frame of the belt retractor and stopping the control disk relative to the belt shaft. Stopping the control disc then activates the blocking device in that a blocking claw mounted on the belt shaft performs a control movement in which it is pushed into a tooth fixed to the frame by means of a guide in a control contour in the control disc.

[0003] Due to the above mentioned objectives, the inertial mass must have a certain mass, otherwise it will not pivot when the withdrawal acceleration is exceeded. Furthermore, the inertial mass must be pivotally mounted on the control disk that rotates with the belt shaft in such a way that it can perform a relative movement with respect to the control disk to control the blocking device. Due to the mass of the inertial mass and its bearing movement, vibrations that impact the belt retractor can lead to undesirable noise generated by the inertial mass.

[0004] A self-locking belt retractor with the above-mentioned characteristics is known, for example, from DE 102010046980 A1. In the belt retractor described there, undesirable noise is prevented by a protrusion that limits the relative movement between the inertial mass and the control disk.

[0005] It is an object of the present invention to provide an alternative solution for avoiding unwanted noise.

[0006] This object is solved by a self-locking belt retractor having the features of the independent claims. Advantageous further embodiments of the belt retractor are given in the dependent claims and in the above and following description, the individual features of the advantageous further embodiments being capable of being combined with one another in a technically reasonable manner.

[0007] This object is solved in particular by a self-locking belt retractor having the initially mentioned features, in which a pretensioning device is provided, which pretensions the inertial mass parallel to the pivot axis in the direction of the control disc. Such a pretensioning device can be realised, for example, by a spring acting on the inertial mass parallel to the pivot axis. However, also other deflectable / deformable elements can be provided as pretensioning device, which preloads the inertial mass parallel to the pivot axis, but still allows (small) relative movements between the inertial mass and the control disc parallel to the pivot axis.

[0008] Such a preload parallel to the pivot axis of the inertial mass can prevent a movement of the inertial mass transverse to the plane of the pivotal movement of the inertial mass, which would cause rattle noise. In particular, if the force provided by the pretensioning device acts directly on the pivot axis, the pivotal movement performed by the inertial mass is hardly or not affected by the pretensioning device. The pretensioning device therefore applies a force parallel to the pivot axis to the inertial mass, so that the inertial mass can move minimally parallel to the pivot axis under high forces, but does not perform any movement in normal operation. In this way, the pretensioning device compensates for the minimum clearance at the axial end of the element forming the pivot axis between the inertial mass and the other components, which would otherwise be required due to tolerances.

[0009] In principle, it is possible to design the pretensioning device onto a component of the self-locking belt retractor. For example, the pretensioning device can be designed as part of a cap covering the control disk device, so that the pretensioning device acts on the inertial mass only after the belt retractor is fully seated. The pretensioning device can also be designed as part of the control disk.

[0010] However, the pretensioning device can preferably be fixed or secured to the control disc as a separate component, which allows it to be mounted on the control disc only after the inertial mass has been attached to the control disc, so that the control disc device can be attached to the other components of the self-locking belt retractor as an independent assembly during mounting.

[0011] The preferably integral pretensioning device is fixed to the control disk, in particular directly (i.e. without further components), preferably by force and / or form closure, which simplifies mounting: for example a snap connection can be designed between the pretensioning device and the control disk.

[0012] In particular in this connection it can be provided that the pretensioning device has a deflectable spring arm which extends parallel to the control disc, such that the deflection of the spring arm, in particular of its free end, is approximately parallel to the pivot axis of the control disc, while the spring arm extends perpendicular to the pivot axis.

[0013] Preferably, exactly one component with a deflectable spring arm is provided, which forms the pretensioning device.

[0014] As a rule, the pivot axis is defined by a protrusion designed on the inertial mass, which in particular has a circular cross-section. In this case, it is proposed that the pretensioning device is provided with a corresponding receptacle for the protrusion of the inertial mass, in the case of the formation of a spring arm, the receptacle is preferably arranged at the (free) end of the spring arm. In the assembled state, the protrusion designed on the inertial mass then engages in a receptacle on the spring arm, the protrusion and the receptacle having a corresponding cross-sectional design (in particular circular).

[0015] However, in an alternative embodiment it may also be provided that the spring arm has a protrusion which engages in a corresponding receptacle in the inertial mass to form the pivot axis of the inertial mass.

[0016] In order to prevent the projection from being inadvertently disengaged from the receptacle, particularly if a receptacle is formed at the end of the deflectable end of the spring arm, it is proposed that the deflectable end of the spring arm is at least partially surrounded by a locking web. At least one locking web can be designed on another component of the belt retractor. Preferably, however, the locking web is designed integrally with the spring arm and thus as a component of the integral pretensioning device. The locking web is arranged circumferentially (with respect to the pivot axis of the inertial mass) around the free end of the spring arm. If a projection on the inertial mass projects from the receptacle at the end of the spring arm, the projection is pressed back into the receptacle by the at least one locking web. The locking web is especially designed in such a way that it circumferentially surrounds the free end of the spring arm over at least 180°, preferably at least 250°.

[0017] In order to prevent the projection of the inertial mass along the spring arm from projecting out of the receptacle at the end of the spring arm, it is proposed that the spring arm has a stop projecting at a distance from its deflectable end in the direction of the control disk, which stop is arranged adjacent to the receptacle at the end of the spring arm in such a way that the projection cannot leave the receptacle.

[0018] An independent invention for solving the first mentioned object, independently of the above mentioned solution, can also be seen in that at least one tapered protrusion is provided to form the pivot axis. It is therefore proposed that the protrusion defining the pivot axis, located in particular either on the inertial mass itself or on another component of the belt retractor (for example generally on the spring arm, the control disk or the cover cap), tapers towards its end, i.e. its cross section becomes smaller towards the end. Such protrusions defining the pivot axis usually have a circular cross-sectional design. The tapered design of the protrusion provides a more point-like bearing point (as opposed to a flat bearing), which, in particular in combination with a preload, reduces friction during the pivoting movement of the inertial mass.

[0019] In this connection, it is particularly envisaged that exactly two tapered protrusions are arranged on either side of the inertial mass. In one embodiment, the tapered protrusions are designed integrally with the inertial mass and are arranged in corresponding receptacles (in the control disk, on the spring arm or on the cap). However, in alternative embodiments, the protrusions can also be designed on the control disk and on the spring arm or on the cap.

[0020] In order to ensure that the receptacle has a predetermined bearing point, it is proposed that the or each receptacle for the tapered protrusion is designed as a conical trough. Such a conical trough also ensures that the protrusion returns to the predetermined bearing point if a force perpendicular to the pivot axis is applied to the protrusion during operation. The opening angle of the conical trough is preferably slightly larger (in particular greater than 1° and less than 5°) than the angle of the tip of the protrusion. [Brief description of the drawings]

[0021] The invention and the technical environment are explained below by way of example with reference to the figures, in which: [Figure 1a] FIG. 2 shows a side view of a self-locking belt retractor having a non-oscillating inertial mass. [Figure 1b] 1b shows the belt retractor of FIG. 1a with the inertial mass oscillating. [Diagram 2] 2 shows a control disk device for the belt retractor of FIG. 1; [Diagram 3] FIG. 2 shows an exploded view of the control disk device. [Figure 4] 3 shows a side view of the inertial mass of the control disk device of FIG. 2; [Diagram 5] 3 shows a cross-sectional view of the control disk device of FIG. 2 without the inertial mass. [Figure 6] FIG. 3 shows a perspective view of the pretensioning device of the control disc device of FIG. 2. [Figure 7] FIG. 2 shows an exploded view of the self-locking belt retractor of FIG. 1.

[0022] The self-locking belt retractor shown in Figures 1a, 1b and 7 comprises a frame 12 on which a belt shaft 13 is rotatably mounted for retracting a safety belt (not shown).

[0023] The self-locking belt retractor 11 also comprises a blocking device 16 which can be used to block the safety belt from being pulled out from the belt shaft 13. For this purpose, the blocking device 16 has a blocking claw 17 which can be activated to block a rotational movement of the belt shaft 13 and which, in the activated state, engages with external teeth 18 on the frame 12 of the belt retractor 11.

[0024] In order to activate the blocking claw 17, the belt retractor 11 has a control disk device 1 comprising a control disk 2, an inertial mass 3, a spring 14 and a pretensioning device 5, the inertial mass 3 being pivotally layered on the control disk 2 and subjected to a spring force by the spring 4.

[0025] In the assembled state, the control disk device 1 is covered by a cap 15 (see FIG. 7) which is not shown in FIGS. 1a and 1b.

[0026] During the extension of the safety belt, the control disk device 1 first rotates together with the belt shaft 13. In this state, the inertial mass 3, as represented in FIG. 1a, does not yet oscillate. As soon as a predefined extraction acceleration is exceeded during extraction, the inertial mass 3 shown in FIGS. 1a and 1b oscillates about the pivot axis 4 (see FIG. 1b). The inertial mass 3 engages with teeth that stop the control disk 2 relative to the belt shaft 13. During the subsequent relative movement of the belt shaft 13 to the stopped control disk 2, the blocking claw 16 is actuated by a guide in a control contour in the control disk 2, which brings the blocking claw 16 into engagement with an external tooth 18 on the frame 12. This also blocks the rotational movement of the belt shaft 13 relative to the frame 12.

[0027] The functioning of the self-locking belt retractor described above is known per se from the prior art.

[0028] Firstly, it is proposed here that the control disc device 1 comprises a pretensioning device 5. The integrated pretensioning device 5 is designed in such a way that it can be fixed to the control disc 3 in a force-fit and form-fit manner by means of a snap connection (see in particular FIG. 5).

[0029] As can be seen especially from the detailed view in figure 6, the pretensioning device 5 comprises a deflectable spring arm 6 which has a receptacle 7.1 at its deflectable end. The deflectable end of the spring arm 6 is surrounded by a locking web 9. In addition, the spring arm 6 has a stop 10 which projects towards the control disc 2 (downwards in figure 5).

[0030] In the assembled state of the belt retractor 11, a projection 8.1 of the inertial mass 3, which determines the pivot axis 4, is arranged in a receptacle 7.1 of the spring arm 6.

[0031] The pretensioning device 5 is dimensioned in such a way that the spring arm 6 pretensions the inertial mass 3 via a protrusion 7.1 parallel to the pivot axis 4 in the direction of the control disc 2, so that any play that would otherwise be present is cancelled out and the inertial mass 3 cannot perform any relative movement in the direction of the pivot axis 4 with respect to the control disc 2 which would generate rattling noise.

[0032] The locking webs 9 and the stops 10 are arranged and designed in such a way that the projection 8.1 of the inertial mass 3 is prevented from being accidentally disengaged from the receptacle 7.1.

[0033] On the other hand, it is proposed that the inertial mass 3 has protrusions 8.1 and 8.2 on both sides so as to form the pivot axis 4, which are pointed (see FIG. 4).

[0034] In the assembled state, the projection 8.1 is located in a receptacle 7.1 designed on the spring arm 6 of the pretensioning device 5, and the projection 8.2 is located in a receptacle 7.2 designed in the control disk (see figures 3 and 5). The receptacles 7.1 and 7.2 are designed as conical recesses, whereby the tapered projections 8.1 and 8.2 and the receptacles 7.1 and 7.2 each have only point-like contacts between them. [Explanation of symbols]

[0035] 1 Control disk device 2 Control Disk 3 Inertial mass 4 Pivot axis 5 Pretensioning device 6 Spring Arm 7.1 Receptacles 7.2 Receptacles 8.1 Projections 8.2 Projections 9. Rock Web 10 Stop part 11 Belt retractor 12 Frames 13 Belt shaft 14 Spring 15 Cap 16 Blocker 17 Blocking claw 18 Outer teeth

Claims

1. A self-locking belt retractor (11), A frame (12); a belt shaft (13) rotatably mounted within the frame (12) and capable of winding up a safety belt; a blocking device (16) for blocking the belt shaft (13) when a predetermined unwinding acceleration of the safety belt is exceeded in the unwinding direction of the safety belt; A control disk device (1) mounted on the belt shaft (13), A control disk (2); an inertial mass (3) pivotally mounted on the control disk (2) about a pivot axis (4); A control disk device (1), A belt retractor (11), characterized in that the inertial mass (3) is provided with a pretensioning device (5) for pretensioning parallel to the pivot axis (4) in the direction of the control disc (2).

2. 2. The belt retractor (11) according to claim 1, wherein the pretensioning device (1) is fixed to the control disc (2) as a separate component.

3. 3. The belt retractor (11) according to claim 1 or 2, wherein the pretensioning device (5) comprises a deflectable spring arm (6) extending parallel to the control disc (2).

4. 4. A belt retractor (11) according to claim 3, wherein the spring arm (6) has a receptacle (7.1) for a protrusion (8.1) designed on the inertial mass (3) so as to form the pivot axis (4).

5. 4. The belt retractor (11) according to claim 3, wherein the spring arm (6) has a protrusion that engages in a receptacle in the inertial mass (3) to form the pivot axis.

6. 4. The belt retractor (11) according to claim 3, wherein the deflectable end of the spring arm (6) is at least partially surrounded by a locking web (9).

7. 4. A belt retractor (11) according to claim 3, wherein the spring arm (6) has a stop (10) projecting at a distance from its deflectable end in the direction of the control disc (2).

8. 3. A belt retractor (11) according to claim 1 or 2, characterized in that at least one tapered projection (8.1, 8.2) is provided to define said pivot axis (4).

9. 9. The belt retractor (11) according to claim 8, wherein exactly two tapered protrusions (8.1, 8.2) are arranged on either side of the inertial mass (3).

10. 9. The belt retractor (11) according to claim 8, wherein the receptacles (7.1, 7.2) for the tapered projections (8.1, 8.2) are designed as conical troughs.

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