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 present invention relates to a self-locking belt retractor having a belt shaft rotatably mounted within a frame and capable of winding up a safety belt, a blocking device that prevents the belt shaft from moving when the safety belt exceeds a predetermined pulling acceleration in the pulling direction of the safety belt, and a control disk device mounted on the belt shaft and particularly spring-biased in the extension direction of the safety belt, wherein the control disk device comprises 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 is particularly aligned parallel to the axis of rotation of the belt shaft.

[0002] Self-locking belt retractors are generally used in vehicle safety belt systems to retract an unfastened safety belt into a parked position and to allow for variable elongation of the safety belt with as little slack as possible. For this purpose, the belt retractor is rotatably mounted within a frame and has a belt shaft that is spring-biased in the take-up direction and onto which the safety belt can be wound. Further, the belt retractor has a blocking device that is activated when a predetermined draw acceleration of the safety belt is exceeded, whereby the belt shaft is subsequently blocked in the belt withdrawal direction. The blocking device includes a blocking pawl mounted on the belt shaft, the movement of which is controlled by a control disk device rotatably mounted on the belt shaft. The control disk of the control disk device is spring-biased in the belt withdrawal direction of the belt shaft and rotates with the belt shaft below a predetermined draw acceleration of the safety belt. An inertial mass body is pivotally mounted on the control disk, and the inertial mass body pivots when a predetermined draw 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 disk then activates the blocking device in that the blocking pawl mounted on the belt shaft performs a control movement in which it is pushed into teeth fixed to the frame by a guide in a control contour within the control disk.

[0003] Due to the above-described purpose, the inertial mass body must have a certain mass, otherwise it will not pivot when the draw acceleration is exceeded. Further, the inertial mass body must be pivotally mounted on a control disk that rotates with the belt shaft in such a manner that it can perform a relative movement with respect to the control disk in order to control the blocking device. Due to the mass of the inertial mass body and its supporting movement, vibrations that impact the belt retractor can lead to undesirable noise generated by the inertial mass body.

[0004] A self-locking belt retractor possessing the above features is known, for example, from German Patent No. 102010046980(A1). In the belt retractor described therein, undesirable noise is prevented by a projection that limits the relative motion between the inertial mass and the control disk.

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

[0006] This objective is addressed by a self-locking belt retractor having the features of the independent claim. Advantageous further embodiments of the belt retractor are given in the dependent claims and in the preceding and following descriptions, and the individual features of the advantageous further embodiments can be combined with each other in a technically reasonable manner.

[0007] This objective is particularly addressed by a self-locking belt retractor having the features described earlier, which provides a pretensioning device that applies pretension to the inertial mass parallel to the pivot axis in the direction of the control disk. Such a pretensioning device can be realized, for example, by a spring acting on the inertial mass parallel to the pivot axis. However, other deflectable / deformable elements can also be provided as pretensioning devices that preload the inertial mass parallel to the pivot axis, but still allow for (small) relative motion between the inertial mass and the control disk parallel to the pivot axis.

[0008] Such preloading parallel to the pivot axis of an inertial mass can prevent the inertial mass from moving transversely to the plane of its pivot motion, which would cause rattling noises. In particular, when the force provided by the pretensioning device acts directly on the pivot axis, the pivot motion performed by the inertial mass is little to no effect on the pretensioning device. Thus, the pretensioning device applies a force parallel to the pivot axis to the inertial mass, and as a result, the inertial mass can move minimally parallel to the pivot axis under a large force, but does not move at all under normal operation. In this way, the pretensioning device compensates for the minimum clearance at the axial ends of the elements forming the pivot axis between the inertial mass and other components. This minimum clearance is otherwise required due to tolerances.

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

[0010] However, it is preferable that the pretensioning device can be fixed or attached to the control disk as a separate component. This allows the pretensioning device to be mounted to the control disk only after the inertial mass has been attached to the control disk, thereby allowing the control disk device to be mounted to the other components of the self-locking belt retractor as an independent assembly during mounting.

[0011] Preferably, the integrated pretensioning device is fixed to the control disk, particularly directly (i.e., without further components), by force and / or shape closure, which simplifies installation. For example, a snap connection can be designed between the pretensioning device and the control disk.

[0012] In particular in this regard, the pretensioning device may be provided to have a deflectable spring arm extending parallel to the control disk. Thus, the deflection of the spring arm, especially at its free end, is substantially parallel to the pivot axis of the control disk, while the spring arm extends perpendicular to the pivot axis.

[0013] Preferably, a single component is provided which comprises a deflectable spring arm that forms a pretensioning device.

[0014] In principle, the pivot axis is designed on an inertial mass body and is defined in particular by a projection having a circular cross-section. In this case, it is proposed that a corresponding receptacle for the projection of the inertial mass body is provided to the pretensioning device, and in the case of forming a spring arm, the receptacle is preferably located at the (free) end of the spring arm. In the assembled state, the projection designed on the inertial mass body then engages with the receptacle on the spring arm, and the projection and the receptacle have a corresponding cross-sectional design (particularly circular).

[0015] However, in an alternative embodiment, the spring arm may also be provided to have a projection that engages with a corresponding receptacle within the inertial mass body to form a pivot axis for the inertial mass body.

[0016] In particular, when 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 be at least partially surrounded by a lock web to prevent the projection from unexpectedly disengaging from the receptacle. At least one lock web can be designed on another component of the belt retractor. However, preferably, the lock web is designed integrally with the spring arm and therefore as a component of the integrated pretensioning device. The lock web is circumferentially positioned around the free end of the spring arm (with respect to the pivot axis of the inertial mass). If a projection on the inertial mass protrudes from the receptacle at the end of the spring arm, the projection is pushed back into the receptacle by at least one lock web. The lock web is particularly designed to surround the free end of the spring arm circumferentially over at least 180°, preferably at least 250°.

[0017] To prevent the projection of the inertial mass along the spring arm from protruding from the receptacle at the end of the spring arm, it is proposed that the spring arm have a stopper that protrudes toward the control disk at a certain distance from its deflectable end. This stopper is positioned adjacent to the receptacle at the end of the spring arm in a manner that prevents the projection from exiting the receptacle.

[0018] An independent invention for solving the aforementioned objective is also evident in that, independently of the solutions described above, at least one tapered projection is provided to form a pivot axis. Thus, it is proposed that the projection defining the pivot axis, which is located either on the inertial mass itself or on another component of the belt retractor (e.g., generally on a spring arm, control disc, or cover cap), tapers toward its end, i.e., its cross-section becomes smaller toward its end. Such a projection defining the pivot axis usually has a circular cross-sectional design. The tapered design of the projection provides more point-like support points (as opposed to flat support parts), which reduces friction during the pivot motion of the inertial mass, especially in combination with preloads.

[0019] In this regard, it is particularly assumed that exactly two tapered projections are positioned on both sides of the inertial mass. In one embodiment, the tapered projections are designed integrally with the inertial mass and are located within the corresponding receptacle (on the control disk, on the spring arm, or on the cap). However, in alternative embodiments, the projections may also be designed on the control disk and on the spring arm or on the cap.

[0020] To ensure that the receptacle has a predetermined support point, it is proposed that the receptacle for the tapered projection, or each receptacle, be designed as a conical trough. Such a conical trough also ensures that the projection returns to the predetermined support point when a force perpendicular to the pivot axis is applied to the projection during operation. The opening angle of the conical trough is preferably slightly greater than the angle of the tip of the projection (particularly greater than 1° and less than 5°). [Brief explanation of the drawing]

[0021] The present invention and its technical environment will be described below with reference to the figures. The following is a schematic diagram. [Figure 1a] A side view of a self-locking belt retractor with a non-oscillating inertial mass is shown. [Figure 1b] Figure 1a shows a belt retractor in a state where the inertial mass is oscillating. [Figure 2] Figure 1 shows the control disk device of the belt retractor. [Figure 3] This shows an exploded view of the control disk device. [Figure 4] Figure 2 shows a side view of the inertial mass of the control disk device. [Figure 5] Figure 2 shows a cross-sectional view of the control disk device without an inertial mass. [Figure 6] Figure 2 shows a perspective view of the pretensioning device for the control disk device. [Figure 7] Figure 1 shows an exploded view of a self-locking belt retractor.

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

[0023] The self-locking belt retractor 11 also comprises a blocking device 16 which can be used to prevent the safety belt from being pulled out of the belt shaft 13. For this purpose, the blocking device 16 has a blocking pawl 17 which can be activated to block the 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] To activate the blocking pawl 17, the belt retractor 11 has a control disk device 1 which comprises a control disk 2, an inertial mass 3, a spring 14 and a pretensioning device 5, the inertial mass 3 being pivotably laminated on the control disk 2 and being acted upon by a spring force by means of a spring 4.

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

[0026] During extension of the safety belt, the control disk device 1 initially rotates together with the belt shaft 13. In this state, the inertial mass 3 has not yet oscillated, as shown in FIG. 1a. As soon as a draw acceleration during pulling out exceeds a predetermined draw acceleration, the inertial mass 3 shown in FIGS. 1a and 1b oscillates about a pivot axis 4 (see FIG. 1b). The inertial mass 3 engages with teeth which stop the control disk 2 relative to the belt shaft 13. During the subsequent relative movement of the belt shaft 13 relative to the stopped control disk 2, the blocking pawl 16 is actuated by a guide in a control contour in the control disk 2 and the blocking pawl 16 is engaged with the external teeth 18 on the frame 12. This also blocks the rotational movement of the belt shaft 13 relative to the frame 12.

[0027] The function of the self-locking belt retractor described above is itself known from prior art.

[0028] First, it is proposed that the control disk device 1 includes a pretensioning device 5. The integrated pretensioning device 5 is designed to be fixed to the control disk 3 by snap connections (see Figure 5 in particular) in a pressure-fit and shape-fit manner.

[0029] As can be seen particularly in the detailed view of Figure 6, the pretensioning device 5 includes a deflectable spring arm 6 having a receptacle 7.1 at its deflectable end. The deflectable end of the spring arm 6 is surrounded by a lock web 9. In addition, the spring arm 6 has a stopper 10 that protrudes toward the control disk 2 (downward in Figure 5).

[0030] In the assembled state of the belt retractor 11, the projection 8.1 of the inertial mass body 3 that determines the pivot axis 4 is located within the receptacle 7.1 of the spring arm 6.

[0031] The pretensioning device 5 is sized such that a spring arm 6 applies pretension to the inertial mass 3 via a projection 7.1 parallel to the pivot axis 4 in the direction of the control disk 2, thereby canceling out any play that would otherwise exist, and preventing the inertial mass 3 from making any relative motion in the direction of the pivot axis 4 with respect to the control disk 2 that would generate rattling noise.

[0032] The lock web 9 and the stopper 10 are positioned and designed in such a manner that the protrusion 8.1 of the inertial mass 3 is prevented from unexpectedly detaching from the receptacle 7.1.

[0033] On the other hand, it has been proposed that the inertial mass 3 has protrusions 8.1 and 8.2 on both sides to form a pivot axis 4, and these are pointed (see Figure 4).

[0034] In its assembled state, projection 8.1 is located within receptacle 7.1 designed on the spring arm 6 of the pretensioning device 5, and projection 8.2 is located within receptacle 7.2 designed on the control disk (see Figures 3 and 5). Receptacles 7.1 and 7.2 are designed as conical recesses, so that the tapered projections 8.1 and 8.2 and receptacles 7.1 and 7.2 have only a point-like contact between them. [Explanation of symbols]

[0035] 1. Control disk device 2. Control disk 3 Inertial mass 4 Pivot axis 5. Pretensioning device 6 spring arms 7.1 Receptacle 7.2 Receptacles 8.1 Projections 8.2 Protrusions 9 Lockweb 10 Stop part 11 Belt Retractor 12 frames 13 Belt shaft 14 springs 15 caps 16 Blocker 17 Blocking claw 18 External teeth

Claims

1. A self-locking belt retractor (11), Frame (12) and A belt shaft (13) is rotatably mounted within the frame (12) and capable of winding up a safety belt, In the direction in which the safety belt is pulled out, a blocking device (16) is provided to block the belt shaft (13) when the pulling acceleration of the safety belt exceeds a predetermined value, A control disk device (1) mounted on the belt shaft (13), Control disk (2), An inertial mass body (3) is mounted on the control disk (2) so as to be pivotable around a pivot axis (4), A control disk device (1) comprising, A belt retractor (11) is provided, characterized in that a pretensioning device (5) is provided that applies pretension to the inertial mass body (3) in the direction of the control disk (2) and parallel to the pivot axis (4).

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

3. The belt retractor (11) according to claim 1 or 2, wherein the pretensioning device (5) has a deflectable spring arm (6) that extends parallel to the control disk (2).

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

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

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

7. The belt retractor (11) according to claim 3, wherein the spring arm (6) has a stop portion (10) that protrudes in the direction of the control disk (2) at a certain distance from its deflectable end.

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

9. The belt retractor (11) according to claim 8, wherein exactly two tapered projections (8.1, 8.2) are located on both sides of the inertial mass (3).

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

Images