Retractor for safety belt device

Abstract

The invention relates to a retractor (1) for a safety belt device, comprising:-a frame (3) for fastening the retractor (1) to a vehicle structure or to a vehicle stationary seat, and-a spindle (2) which is rotatably mounted in the frame (3), and-a safety belt (4), one end of which is wound around the spindle (2), and an electric drive (5) which, when activated, drives the spindle (2) in a rotational movement, the electric drive (5) being permanently connected to the spindle (2).

Description

[0001] The invention relates to a retractor for a safety belt arrangement, the retractor comprising the features mentioned in the preamble of claim 1.

[0002] The purpose of the retractor in a safety belt arrangement is to retract a safety belt in the safety belt arrangement in order to restrain an occupant seated on a seat of a vehicle. The retractor is therefore fixed at a vehicle structure via a frame, wherein the frame comprises at least two opposite bearing flanges, each bearing flange having a bearing opening in which a spindle is mounted in a rotatable manner on which a safety belt can be wound. The spindle is tensioned in the direction of retraction of the safety belt via a tension spring, one end of which is mounted on the frame and the other end of which is mounted on the spindle.

[0003] It is further known from WO 03 / 099619 A2 to provide the retractor with a reversible or irreversible pretensioner which, when activated, tensions the safety belt and pulls out the slack part of the safety belt in order to have the safety belt lie tight against the occupant in the event of a subsequent accident or to prepare for a possible subsequent accident. Since the spindle has to be supported in the frame in a rotatable manner without being hindered in the rotational movement by the pretensioner, the pretensioner comprises a drive wheel which is driven by the pretensioner and which can be coupled to the spindle via a clutch. During normal use, the drive wheel and the pretensioner are therefore decoupled by the clutch being in an open state. If the pretensioner is activated, the drive wheel needs to be connected to the spindle via the closed clutch in a first step before the rotational movement of the drive wheel is transmitted to the spindle. The clutch comprises two locking jaws which are guided in a slidable manner at the drive wheel and which perform a movement into the toothing of a ring gear fixed at the spindle when the drive wheel is driven in rotational movement. The movement of the locking jaws is forced by a friction ring which is connected with the locking jaws and which abuts at a side wall of the housing, so that the friction ring is braked via the friction with the drive wheel.

[0004] Another retractor is known from document DE 10 2020 207 557 B3, in which, in addition to a pre-tensioning function, the spindle can also be driven to achieve a tactile warning function. In the tactile warning function, the spindle is periodically driven in the unwinding direction, while simultaneously rotating in the retraction direction via a tension spring between these periodic rotations. In this function, the drive wheel is also connected to the spindle via a locking pawl to achieve the tactile warning function. In this embodiment, the locking pawl can also be considered a clutch that needs to be engaged before rotational motion can be transmitted. Due to the periodic drive of the spindle in the unwinding direction and the rotation in the retraction direction occurring between rotations in the unwinding direction, the spindle rotates alternately in the unwinding and retraction directions. Therefore, the seatbelt is driven to a considerable jerking motion, while simultaneously striking the occupant's clothing, thereby drawing the occupant's attention. The tactile warning function can be activated when the occupant's attention should be increased, such as in critical driving situations, under the default settings of important driving functions, or when it is necessary to easily wake an occupant who is napping during rest after a predetermined time.

[0005] The proposed solution has several drawbacks. First, the retractor involves a highly complex design with a drive wheel, gear ring, clutch, and locking pawl, leading to high cost and increased installation space. Furthermore, since the drive wheel requires a certain amount of time and rotation angle to engage the clutch after activating the electric drive for pre-tensioning or tactile warning functions, there is a delay in the transmission of rotational motion to the spindle. This delay results in time loss and reduced efficiency in transmitting the drive wheel's rotation to the spindle.

[0006] In view of this background, the object of the present invention is to provide a retractor with an electric drive device for driving a mandrel, which is more cost-effective, occupies less installation space, and is able to transmit the rotational motion of the electric drive device to the mandrel with higher efficiency and lower time delay.

[0007] According to the present invention, a retractor comprising the features of claim 1 is provided. Further preferred embodiments of the invention can be obtained from the dependent claims, drawings, and related description.

[0008] According to the basic idea of ​​the present invention, an electric drive device is permanently connected to the spindle.

[0009] The proposed design boasts a highly compact structure, as there is no clutch between the electric drive unit and the spindle, reducing the necessary installation space and lowering the cost of the retractor. Furthermore, due to the permanent connection, the spindle is immediately driven upon activation of the electric drive unit, without any delay. During normal use of the retractor, the electric drive unit is deactivated in a power-off mode. Therefore, the movable parts of the electric drive unit are driven along with the spindle in this state. When the electric drive unit is activated, it applies torque to the spindle, which can be used depending on the direction to increase or decrease the retraction force acting on the seatbelt. Thus, by increasing the retraction force, the seatbelt can be wound into the parking position, or any slack sections can be pulled out. Additionally, a tactile warning function can be implemented. Furthermore, by reducing the retraction force, a comfort function can be implemented.

[0010] Furthermore, the proposed electric drive unit includes a rotary drive shaft extending to the outside and is provided with a connector that is directly or indirectly fixed to the shaft and directly or indirectly fixed to the mandrel. The proposed design achieves a compact design for the retractor, wherein the drive motion of the electric drive unit can be very easily transmitted to the mandrel, and wherein the connector provides the connection between the electric drive unit and the mandrel.

[0011] In a preferred embodiment, the connector is designed as a disc with a first recess arranged coaxially on one side and a second recess arranged coaxially on the other side, its central axis being rotatably fixed in the first recess and the shaft being rotatably fixed in the second recess. This connector design allows for very easy transmission of drive motion to the spindle, as the disc also performs rotational motion like the spindle, which can be transmitted to the spindle in a 1:1 ratio. No further deflection or alteration is required for the drive motion from the connector to the spindle.

[0012] Furthermore, the proposed electric drive unit includes a housing fixed to the frame. Therefore, the frame of the retractor serves not only to support the spindle and the vehicle structure, but also to secure the housing covering the electric drive unit to the outside, and to hold the stationary portion of the electric drive unit in place when the electric drive unit is activated.

[0013] Furthermore, it is proposed to design the housing as a tube, and to provide a cover that closes the housing on one side, with the electric motor of the electric drive device fixed to the cover. The housing is designed as a tube so that the electric motor can be inserted into the housing from one side. Then, the electric motor is fixed in a predetermined position relative to the housing by the cover, which fixes itself to the housing.

[0014] Furthermore, a rotating spring is proposed that tensions the mandrel in the retraction direction of the seatbelt. This tensioning spring causes the seatbelt to automatically rewind after being unbuckled by releasing the buckle from the latch. The rotating spring applies a basic retraction force to the mandrel, and thus to the seatbelt, adding to the retraction force applied by the electrically driven mechanism.

[0015] Furthermore, it is proposed to fix the first end of the rotary spring directly or indirectly to the connector. Therefore, by using a separate connector to connect the spring to the spindle, the necessary installation space can be further reduced and costs can be lowered.

[0016] Furthermore, it is proposed that the first recess of the connector be designed as a tubular protrusion with a chamber disposed therein, and that the tubular protrusion includes a non-circular external geometry, to which the rotational movement of the first end of the spring relative to the connector is fixed. The proposed solution further utilizes the first recess to connect the end of the spring without any additional means. The non-circular external geometry provides a force-locking and force-fit connection between the first end of the spring and the connector solely by its shape, and thereby indirectly connects it to the spindle.

[0017] Furthermore, it is proposed to design the electric drive device as an electric motor with an electric drive rotor whose mass is less than 0.1 kg.

[0018] The present invention will now be described with reference to the accompanying drawings and a preferred embodiment, wherein:

[0019] Figure 1 A retractor with an electric drive unit is shown in an assembled state, and

[0020] Figure 2 An exploded view shows a retractor with an electric drive.

[0021] exist Figure 1 In the middle, it is shown that there are frames 3 and Figure 2 The retractor 1 of the spindle 2 is shown, with the seat belt 4 wound around the spindle 2. The spindle 2 is rotatably mounted in two opposing flanges of the frame 3, as has long been known in the prior art. The retractor 1 also includes an irreversible pretensioner 9 fixed to the right side of the frame 3 and an electric drive 5 fixed to the left side of the frame 3. The frame 3 itself includes an attachment protrusion extending on its underside for securing the retractor 1 to the vehicle structure or vehicle seat in a vehicle-mounted manner.

[0022] The electric drive unit 5 includes a tubular housing 53, an electric motor 52, and a cover 51. The stator portion of the electric motor 52 is fixed to the cover 51, and the electric motor is inserted into a free opening in the housing 53, which is closed by the cover 51 after the electric motor 52 is inserted. The cover 51 is fixed to the housing 53 such that the electric motor 52 is also fixed in a predetermined position relative to the housing 53.

[0023] The electric motor 52 also includes an electrically driven rotor with a rotatable drive shaft, the mass of which is less than 0.1 kg. The shaft is... Figure 2 The rotor 52 is not shown and extends toward the spindle 2. Furthermore, a connector 7 is provided, which is designed as a disc having a first recess 71 extending toward the spindle 2 and a second recess 72 extending toward the electric motor 52. The first recess 71 and the second recess 72 each include a chamber having a non-circular or polygonal cross-section, wherein the shaft of the electric motor 52 is rotatably fixed in the chamber of the second recess 72, and the spindle 2 is rotatably fixed in the chamber of the first recess 71 by a protrusion 21. Therefore, the connector 7 forms a permanent rotational fixed connection between the rotor of the electric motor 52 and the spindle 2.

[0024] In addition, a rotating helical spring 6 is provided, the first inner end 61 of which is connected to the external geometry of the first recess 71 of the connector 7, and its second outer end 62 is connected to the housing 53 of the electric drive unit 5. A spring plate 8 is arranged between the spindle 2 and the rotating spring 6, and is attached to the outside of the frame 3 to separate the rotating spring 6 from the spindle 2 and the frame 3. The spring plate 8 provides lateral support for the spring 6 to hold the spring 6 in its helical geometry and protect the rotating spring 6. The rotating spring 6 is rotatably fixed in the first recess 71 via the connector 7 and the protrusion 21 to the upward winding direction of the seat belt 4 to tension the spindle 2 so that it can be wound upward to the parking position after the seat belt 4 is unbuckled.

[0025] The electric drive unit 5 and the electric rotor of the electric motor 52 are permanently connected to the spindle 2 via a connector 7, so that the electric rotor of the electric motor 52 rotates together with the spindle 2 in the pull-out and retraction directions during normal use in the power-off mode. The electric rotor is designed to have a mass of less than 0.1 kg, so that the inertial force will not raise the force of pulling out and retracting the seat belt 4 to an unacceptable level.

[0026] For example, the electric drive unit 5 is activated to assist the rotating spring 6 in winding the seat belt upwards, pulling out any possible slack in the seat belt 4 to achieve reversible pretensioning, or to provide a tactile warning, for example, by periodically increasing and / or decreasing the tension in the seat belt 4. Due to the permanent connection between the electric rotor and the spindle 2, rotational torque is transmitted from the electric rotor of the electric motor 52 to the spindle 2 without any delay or loss. Furthermore, the design is very compact, requiring only a single additional component to connect the electric drive unit 5 to the spindle 2 via the connector 7. Because of the fixed connection to the rotor of the electric drive unit 5 and the spindle 2, the connector 7 itself does not require its own bearings.

Claims

1. A retractor (1) for a safety belt arrangement, comprising: - a frame (3) for fastening the retractor (1) at a vehicle structure or at a vehicle stationary seat, and - a spindle (2) which is rotatably supported in the frame (3), and - a safety belt (4) whose one end is wound onto the spindle (2), and - an electric drive (5) which, when activated, drives the spindle (2) into rotational movement, characterized in that - the electric drive (5) is permanently connected with the spindle (2).

2. The retractor (1) according to claim 1, characterized in that - the electric drive (5) comprises a rotational drive shaft which extends to the outside, and - a coupling (7) is provided which is fixed directly or indirectly with the shaft and directly or indirectly with the spindle (2).

3. The retractor (1) according to claim 2, characterized in that - the coupling (7) is designed as a disc which has a first recess (71) arranged coaxially on one side and a second recess (72) arranged coaxially on the other side, wherein the spindle (2) is rotatably fixed in the first recess (71) and the shaft is rotatably fixed in the second recess (72).

4. The retractor (1) according to one of claims 1 to 3, characterized in that - the electric drive (5) comprises a housing (53) which is fixed on the frame (3).

5. The retractor (1) according to claim 4, characterized in that - the housing (53) is designed as a tube, and - a cover (51) is provided which closes the housing (53) on one side, and - an electric motor (52) of the electric drive (5) is fixed at the cover (51).

6. The retractor (1) according to one of claims 1 to 5, characterized in that - a rotational spring (6) is provided which tensions the spindle (2) in the retraction direction of the safety belt (4).

7. The retractor (1) according to one of claims 2 or 3 and according to claim 6, wherein - a first end (61) of the rotational spring (6) is fixed directly or indirectly at the coupling (7).

8. The retractor (1) according to claim 7, characterized in that - the first recess (71) of the coupling (7) is designed as a tubular protrusion with a chamber arranged therein, and - the tubular protrusion comprises a non-circular outer geometry on which the first end (61) of the rotational spring (6) is fixed with respect to a rotational movement of the coupling (7).

9. The retractor (1) according to one of claims 1 to 8, characterized in that - the electric drive (5) is designed as an electric motor (52) with an electric drive rotor whose mass is less than 0.1 kg. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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