Belt retractor

Abstract

The present invention relates to a belt retractor for a seat belt of a motor vehicle, comprising a housing frame (9), a belt shaft (1) rotatably mounted in the housing frame (9), a profile head (2) lockable in relation to the housing frame (9), a force-limiting device (3), a connecting tube (6) at least partially surrounding the force-limiting device (3), and a locking hook (7), wherein the connecting tube (6) is integrally formed with the profile head (2) such that, when the locking hook (7) engages in a locking groove (8), the belt shaft (1) is locked non-rotatably to the housing frame (9) by means of the profile head (2), wherein a stop (12) is formed on the profile head (2) and / or on a profile-head-side end of the connecting tube (6) and is arranged in such a way that, when the locking hook (7) engages in the locking groove (8), the locking hook (7) comes into contact with the stop (12).

Description

[0001] Belt retractor

[0002] Description

[0003] The present invention relates to a belt retractor for a safety belt of a motor vehicle, wherein the belt retractor comprises a housing frame, a belt shaft rotatably mounted in the housing frame, a profile head lockable relative to the housing frame and a force limiting device, wherein the force limiting device is coupled with a first end, in particular in a form-fitting manner, to the profile head and with a second end, in particular in a form-fitting manner to the belt shaft and enables a force-limited relative rotation of the belt shaft relative to the locked profile head.In addition, the belt retractor comprises a connecting tube which is formed in one piece with the profile head and at least partially surrounds the force limiting device, and a locking hook, wherein the locking hook slides over an outer circumference of the connecting tube during the relative rotation of the belt shaft with respect to the locked profile head and, when a predetermined angle of rotation of the belt shaft is reached, falls into a locking groove formed on the circumference of the connecting tube, whereby the connecting tube is coupled to the belt shaft and the belt shaft is locked to the housing frame in a rotationally fixed manner via the profile head when the locking hook falls into the locking groove.

[0004] A belt retractor with the aforementioned features is known, for example, from DE 10 2018 108 089 B4. The general structure and function of such a belt retractor and its components are also known from DE 10 2012 107 557 B3. Thus, the force-limiting device comprises, in particular, at least one torsion bar, wherein a toothing is formed on an end of a torsion bar assigned to the profile head, by means of which toothing the force-limiting device is coupled to the profile head in a rotationally fixed and positively locking manner. The same or a further torsion bar of the force-limiting device preferably also has, at its other end, a toothing by means of which the force-limiting device is coupled to the belt shaft in a rotationally fixed and positively locking manner. The at least one torsion bar is thus arranged, in particular, over a large part of its length within the connecting tube and is connected to the connecting tube in a rotationally fixed and positively locking manner via the first end.

[0005] At least one locking groove is formed on the outer circumference of the connecting tube. The at least one locking groove and the at least one locking hook are arranged and designed such that, when the profile head is locked and the belt shaft rotates relative to the profile head, and thus when the locking hook rotates relative to the connecting tube, rotation is initially possible. The locking hook is thus connected to the belt shaft in a rotationally fixed manner. For this purpose, for example, webs extending at least in sections along the outer circumference can be formed, along which the locking hook initially slides.

[0006] The at least one locking hook can also be rigidly connected to a driver, which engages in a spiral guide groove formed in the connecting tube, so that the driver is displaced in the axial direction upon relative rotation of the locking hook relative to the connecting tube locked to the profile head. The at least one locking groove and, if applicable, the webs can be arranged such that, for example, after a predetermined angle of rotation of, for example, at least 720°, the locking hook engages the locking groove. Due to the locking hook having engaged the locking groove, the belt shaft is connected to the locked profile head via the locking hook, so that further belt extension from the belt shaft is stopped.

[0007] It has now been found that when the locking hook is retracted and the belt shaft is thus coupled to the profile head via the locking hook, an uneven introduction of force into the belt retractor occurs, which can lead to unintentional damage to the belt retractor.

[0008] The object of the present invention is therefore to eliminate the disadvantages described with reference to the prior art and, in particular, to provide a belt retractor in which a more uniform force introduction occurs when the locking hook is retracted.

[0009] A possible solution to the problem is provided by the belt retractor having the features of independent claim 1. Further solutions and advantageous developments can be found in the above and following description as well as the subclaims, wherein individual features of the advantageous developments can be combined with one another in a technically expedient manner.

[0010] The object is achieved in particular by a belt retractor with the features mentioned at the outset, in which a stop is formed on the profile head and / or on an end of the connecting tube on the profile head side and is arranged in such a way that the locking hook comes into contact with the stop when the locking hook falls into the locking groove.

[0011] In other words, the basic concept of the invention is that the stop between the locking hook and the profile head / connecting tube provides an additional force transmission point, where forces are transmitted from the belt shaft via the locking hook into the profile head. Thus, the stop provides an additional point for force transmission in addition to the contact points formed by the locking grooves.

[0012] While the locking groove is formed by a recess / depression in the connecting tube, the stop is preferably formed by a projection or elevation that protrudes from the connecting tube and / or the locking head. The locking hook engages the stop, in particular, with an edge that is arranged at an end of the locking hook associated with the profile head. The edge whose portion engages the stop is, in particular, an edge that runs parallel to the longitudinal axis of the connecting tube.

[0013] In a preferred embodiment, a damping element is provided in front of the stop in the direction of rotation. This damping element, in contact with the locking hook, dissipates energy from the rotational movement of the belt shaft relative to the locked profile head. Such a damping element does not result in an abrupt stop of the force-limited relative rotation of the belt shaft, but rather in a slower deceleration. The damping element can dissipate energy, for example, through deformation work.

[0014] In a preferred embodiment, however, the damping element is designed as a ramp, by means of which the locking hook is pressed against the inside of the belt shaft as it slides over the ramp, whereby the friction between the locking hook and the ramp is increasingly increased. The ramp therefore has a height that increases in the direction of rotation, so that the locking hook is pressed more strongly against the inside of the belt shaft as rotation continues. Energy is thus dissipated via friction between the locking hook and the ramp, with this friction increasing with increasing rotation. The ramp is therefore formed in one piece with the connecting tube, particularly on the outer circumference of the connecting tube.

[0015] The ramp preferably extends over 30° to 90°, particularly preferably over 50° to 70° and most particularly preferably over 60° in the circumferential direction of the outer circumference of the connecting pipe.

[0016] In the area of ​​the ramp, the outer circumference of the ramp increases from the outer circumference of the connecting pipe outside the ramp by 10% to 30%, preferably from 15% to 25%.

[0017] It can also be provided that the height of the stop at the end of the ramp in the radial direction corresponds approximately to 1 to 1.5 times the thickness of the section of the locking hook which comes to rest against the stop.

[0018] In a preferred embodiment, the locking hook is made from sheet metal and, in particular, is adapted to the rounded shape of the outer circumference of the connecting tube by folding. In addition to the ramp, the folding can create a damping effect in that the folded area of ​​the sheet metal is pressed against the inner circumference of the belt shaft by the ramp. In particular, it is provided that the locking hook is rigidly and preferably integrally connected to a driver, wherein the driver engages in a guide groove, preferably helically designed on the connecting tube, wherein the guide groove is arranged on a side of the connecting tube facing away from the profile head and the guide groove in particular has a stop surface against which the driver rests when the locking hook falls into the locking groove.Thus, force is transmitted from the belt shaft to the connecting tube in the area of ​​contact between the driver and a stop surface of the guide groove. Thus, on both sides (in the longitudinal direction of the connecting tube) of the locking grooves, points are formed, each with the stop surface of the guide groove and the stop, where additional force is transmitted from the belt shaft.

[0019] In particular, it can be provided that, in the direction of relative rotation, a recess is formed behind one end of the guide groove, into which the driver engages when the at least one locking hook engages the associated locking groove. In this case, the stop surface of the guide groove would also be formed in the region of the recess, so that the driver rests against the stop surface in the region of the recess in the direction of rotation.

[0020] The invention and the technical environment are explained below using the figures as examples. They show schematically

[0021] Figure 1 : an exploded view of a belt retractor,

[0022] Figure 2: an exploded view of parts of the belt retractor, Figure 3: a profile head and a one-piece formed thereon

[0023] Connecting tube and a locking hook in exploded position,

[0024] Figure 4: the profile head with the connecting pipe and the

[0025] Locking hook in a starting position,

[0026] Figure 5 : the profile head with the connecting pipe and the

[0027] Locking hook when the locking hook is retracted and

[0028] Figure 6: a partial sectional view of the belt shaft with the connecting tube arranged therein and a force limiting device when the locking hook is retracted.

[0029] The belt retractor shown in the figures comprises a housing frame 9, a profile head 2 with a connecting tube 6 formed integrally on the profile head 2, a locking hook 7 with a driver 10 formed integrally on the locking hook 7, a force limiting device 3 formed by a torsion bar, and a belt shaft 1. The force limiting device 3 formed as a torsion bar comprises a first end 4 with a toothing, wherein the first end 4 is coupled in a rotationally fixed manner to the profile head 2. The force limiting device 3 also comprises a second end 5 with a toothing, wherein the second end 5 is coupled in a rotationally fixed manner to the belt shaft 1.

[0030] On the outer circumference of the connecting pipe 6 there are two

[0031] Locking grooves 8 and a helical guide groove 11 are formed. The locking grooves 8 are separated from each other by a web.

[0032] On the outer circumference of the connecting tube 6 there is also a stop 12, to which a ramp 14 is assigned.

[0033] In the initial state shown in Figure 4, the locking hook 7 rests on the web between the locking grooves 8, while the driver 10 engages in the guide groove 11. If the profile head 2 is now locked relative to the housing frame 9 and a relative rotation of the belt shaft 1 relative to the locked profile head 2 occurs, the locking hook 7 is carried by the belt shaft 1, whereby with increasing rotation, due to the engagement of the driver 10 in the guide groove 11, an axial displacement of the locking hook 7 relative to the connecting tube 6 occurs. During this relative rotation of the belt shaft 1 relative to the locked profile head 2, a force-limited belt webbing extension occurs.

[0034] After reaching a rotation angle of slightly more than 720°, the locking hook 7 falls into the locking grooves 8, so that the locking hook 7 comes into contact with stop surfaces of the locking grooves 8, whereby further relative rotation of the belt shaft 1 relative to the connecting tube 6 and the profile head 2 is prevented. This also stops the belt webbing extension. In this state, shown in Figure 5, the driver 10 also comes into contact with a stop surface formed on the guide groove in the direction of rotation in the region of a recess 13 of the guide groove 11, so that at this point too, force is transmitted from the belt shaft 1 via the locking hook 7 to the connecting tube 6. Shortly before reaching the position shown in Figure 5, the locking hook 7 runs onto the ramp 14, whereby the locking hook 7 is pressed radially outwards against an inner side of the belt shaft 1.The friction created between the locking hook 7 and the ramp 14 dampens the relative rotation of the belt shaft relative to the connecting tube 6 or the profile head 2. Since the locking hook 7 is increasingly clamped between the inside of the belt shaft 1 and the ramp 14 with increasing rotation, the damping becomes increasingly stronger.

[0035] The stop 12 is arranged such that the locking hook 7 comes into contact with the stop 12 when the locking hook 7 simultaneously comes into contact with the contact surfaces of the locking grooves 8. At the same time, the driver 10 also comes into contact with the stop surface of the guide groove 11.

[0036] The stop 12 thus ensures a much more even force introduction from the belt shaft 1 into the connecting tube 6 or into the locked profile head 2.

[0037] List of reference symbols

[0038] Belt shaft

[0039] Profile head

[0040] Force limiting device first end second end

[0041] connecting pipe

[0042] locking hook

[0043] locking groove

[0044] Housing frame

[0045] Driver

[0046] guide groove

[0047] stop

[0048] Deepening

[0049] ramp

Claims

Claims 1. Belt retractor for a safety belt of a motor vehicle, comprising a housing frame (9), a belt shaft (1) rotatably mounted in the housing frame (9), a profile head (2) lockable relative to the housing frame (9), a force limiting device (3), wherein the force limiting device (3) is coupled with a first end (4) to the profile head (2) and with a second end (5) to the belt shaft (1) and enables a force-limited relative rotation of the belt shaft (1) relative to the locked profile head (2), a connecting tube (6) at least partially surrounding the force limiting device (3) and a locking hook (7), wherein the locking hook (7) slides over an outer circumference of the connecting tube (6) during the relative rotation of the belt shaft (1) relative to the profile head (2) and, upon reaching a predetermined angle of rotation of the belt shaft (1), engages in a locking groove formed on the circumference of the connecting tube (6). (8) occurs,whereby the connecting tube (6) is coupled to the belt shaft (1), wherein the connecting tube (6) is formed in one piece with the profile head (2), so that the belt shaft (1) is locked to the housing frame (9) via the profile head (2) in a rotationally fixed manner when the locking hook (7) falls into the locking groove (8), characterized in that a stop (12) is formed on the profile head (2) and / or on an end of the connecting tube (6) on the profile head side and is arranged in such a way that the locking hook (7) falls into the, Locking hook (7) comes into contact with the stop (12) in the locking groove (8).

2. Belt retractor according to claim 1, wherein a damping element (14) is formed in front of the stop (12) in the direction of rotation, which damping element (14) dissipates energy of the rotational movement in contact with the locking hook (7).

3. Belt retractor according to claim 2, wherein the damping element is designed as a ramp (14) by which the locking hook (7) is pressed against an inner side of the belt shaft (1) when sliding over the ramp (14).

4. Belt retractor according to one of the preceding claims, wherein the locking hook (7) is rigidly and preferably integrally connected to a driver (10), wherein the driver (10) engages in a guide groove (11) preferably formed in a screw shape on the connecting tube (6), wherein the guide groove (11) is arranged on a side of the connecting tube (6) facing away from the profile head (2).

5. Belt retractor according to claim 4, wherein a recess (13) is formed behind one end of the guide groove (11) in the direction of relative rotation.

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