KR20060108526A - Seatbelt take-up device with friction clutch - Google Patents

Abstract

The present invention relates to a shaft (4), a main spiral spring (7) arranged to apply a compressive stress to the shaft (4) in the winding direction (a) of the seat belt (2), the shaft (4) A ratchet wheel 12 rotatably disposed relative to, a locking device 15 and a ratchet wheel 12 for blocking the rotational movement of the ratchet wheel 12 in a winding direction a Belt winding device (1) comprising a balance spring (20) arranged so that a compressive stress which acts against the compressive stress of the main spiral spring (7) when it is locked can be transmitted to the shaft (4). ), The belt winding device (1) is characterized in that the force transmission between the balance spring (20) and the ratchet wheel (12) is made in a friction coupling manner.

Description

Belt winding device with friction clutch {SEATBELT TAKE-UP DEVICE WITH FRICTION CLUTCH}

1 is an exploded view of a belt winding apparatus according to the present invention.

2 is a view showing the assembled belt winding apparatus.

* Description of the major symbols in the drawings *

1: belt winding device 2: seat belt

3: winding section 4: shaft

5: drive section 6: metal housing

7: main spiral spring

8, 23: outer end 9: plastic housing

10: pin 11, 29: inner end

12: ratchet wheel 13: disc

14: through opening 15: locking device

16: magnet actuator 17: actuated lifter 18: ratchet lever 19, 25: tooth

20: balance spring 21: inner circumference

22: tension spring 24: driven device

26 flank 27 receptacle

28: clutch section 30: planar flank

31: spring

a: winding direction b: unwinding direction

The present invention relates to a belt winding apparatus according to the preamble of claim 1.

Such a belt winding device is known from EP 1 157 905 B1. Known belt winding devices are provided with a primary spiral spring which bends the shaft comprising the belt winding section in the winding direction. In addition, a balance spring is provided which is arranged to act opposite to the main spiral spring. One side of the balance spring is connected to the ratchet wheel through its outer end and the other side is connected to the ring of the friction clutch via its inner end.

In the case of the belt described above, it is required to reduce the winding torque provided to the shaft from the main spiral spring. This reduction in torque occurs as the balance spring is pulled by the main spiral spring during the backward movement of the driver or passenger as the ratchet wheel is locked in the winding direction by the locking device as soon as the belt buckle is locked. At this time. The torque of the main spiral spring is reduced by the torque required to pull the balance spring.

If the driver or passenger is out of the operating range of the balance spring when moving in the opposite direction of the driving direction, ie in the backrest direction, the shaft continues by the wire spring of the friction clutch if the balance spring is blocked by the main spiral spring. It can be rotated in the winding direction to keep the belt winding.

Known belt winding devices have many disadvantages. When the ratchet wheel is unlocked by the belt buckle being released, the ratchet wheel rotates in the winding direction according to the torque transmitted by the balance spring. As the balance spring is completely extended by the rotational movement of the ratchet wheel, the rotational movement of the ratchet wheel stops abruptly. This is due to the fact that the balance spring first blocks the wire spring of the friction clutch so that the ratchet wheel can no longer rotate in the winding direction. The linear spring does not relax until further rotational movement in the winding direction of the shaft is continued. This may cause damage to the balance spring, in particular in the case of a highly elastic balance spring, by causing excessive rotation, and even in the worst case, failure of the balance spring.

Another disadvantage of known belt winding devices is that the reliability of friction clutches comprising linear springs is insufficient. The friction clutch should allow the shaft to rotate in the winding direction even if it is outside the range of action of the balance spring.

It is an object of the present invention to provide a belt winding apparatus which can be manufactured at a low cost while being reliable.

This object is achieved through the features of claim 1.

Preferred embodiments of the invention are set forth in the dependent claims.

The invention is based on the idea that the balance spring is engaged with the ratchet wheel via frictional engagement only in the manner of a friction clutch. If the belt buckle is locked and the operating rotation required to wind the belt exceeds the maximum total rotation of the balance spring, the balance spring can be wound until it is locked by the main spiral spring and then rotated again by the friction clutch. As a result, rotation in the winding direction of the shaft is not prevented. The friction clutch according to the invention acts accurately and uniformly so that the same subjective effect always occurs on the belt operator side. In addition, the balance spring is formed of a friction spring, so that a linear spring does not need to be disposed around the shaft.

Preferably, the ratchet wheel has an inner circumference and is arranged to slide along the inner circumference of the ratchet wheel when the balance spring is fully pulled and then the ratchet wheel is locked and the shaft rotates in the winding direction. That is, the friction clutch is formed around the balance spring itself and the inner circumference of the ratchet wheel. This friction clutch allows the balance spring to continue to rotate, thereby allowing the shaft to continue to rotate in the winding direction when the balance spring's maximum operating range is reached or exceeded.

Tension springs which allow the balance spring to be pressed against the inner circumference of the ratchet wheel in order to increase the compressive force of the balance spring applied to the ratchet wheel to increase both static and kinetic friction between the balance spring and the inner circumference of the ratchet wheel spring) is provided.

The tension spring is formed of a spring piece, and it is also desirable for structural and rapid assembly that the spring piece is inserted into the winding of the balance spring.

In an embodiment of the present invention, preferably, a retraction clutch is provided between the shaft and the balance spring, wherein the retraction clutch has a force from the shaft to the balance spring when the shaft rotates in one direction. On the other hand, allowing the clutch section of the balance spring to move relative to the shaft in the winding direction. The retraction clutch allows the main spiral spring to bend the balance spring through rotation of the shaft when the ratchet wheel is locked. In this case, the torque acting on the shaft by the main spiral spring is reduced by the torque required to attract the balance spring. When the balance spring is unlocked when the belt buckle is released, the ratchet wheel is rotated in the winding direction by the bent (prestressed) balance spring acting on it. Since the anti-retraction clutch according to the invention allows relative movement of the clutch section of the balance spring with respect to the shaft, there is no phenomenon that the ratchet wheel is suddenly braked when the balance spring is completely wound. The ratchet wheel, together with the balance spring, can rotate in the winding direction relative to the shaft until the kinetic energy is completely consumed by the friction action.

Another advantage of the present invention is that there is no need for a ring between the balance spring and the shaft. This spare part reduces manufacturing costs.

Another advantage of the present invention is that the entire spring can be made smaller by eliminating the linear spring.

In an embodiment of the invention, preferably, the retraction prevention clutch comprises a driven device rotatably coupled to the shaft, and a self-separable positive locking can be formed between the driven device and the balance spring. The driven device uses the clutch section of the balance spring to drive the balance spring when the ratchet wheel is locked and the shaft rotates in the winding direction, as a result of which the balance spring is bent by the main spiral spring, thereby winding it back on the shaft. The torque of the main spiral spring acting in the direction decreases. The force transfer between the driven device and the balance spring is via shape coupling. The shape engagement between the follower and the balance spring is such that the shape engagement is automatically released upon relative movement of the clutch section relative to the shaft so that the ratchet wheel is freed in the direction of winding about the shaft or driven device by the balance spring. It is designed to rotate.

The driven device is preferably designed as a driven wheel with at least one receptacle for hooking the balance spring apart. In order to ensure that the balance spring is driven in the winding direction by the driven wheel as soon as possible when the driver or passenger moves backward in the seat back direction, a plurality of receivers distributed around the driven wheel are preferably engaged with the clutch section of the balance spring. Is provided for connection. In this case, the receiving portion is preferably formed with teeth extending radially around the driven wheel.

The balance spring is preferably a spiral spring. By providing the retraction prevention clutch according to the invention, a balance spring of almost the same strength as the main spiral spring used can be used.

According to one preferred embodiment of the invention, a clutch section for forming a shape engagement with the driven device is formed from the inner end of the balance spring. In one embodiment of the simple construction, the clutch section of the balance spring is shaped like a hook. The hook allows the balance spring to engage the receptacle of the follower, with the hook-type clutch section moving beyond the receptacle of the follower in a winding direction relative to the shaft. Of course, the clutch section of the balance spring may be formed as a separate component connected to the balance spring.

In order to simplify assembly, it is preferred that the shafts be formed in several parts, in particular in such a way that they can be joined together. In this case, the driven device may be integrally formed with the shaft or part of the shaft.

The present invention will be described in more detail with reference to the embodiments shown in the drawings.

The belt winding device 1 is shown in the figure. The belt winding device 1 allows the seat belt 2 to be wound around the belt winding section 3 of the shaft 4. The shaft 4 consists of two parts and consists of a belt winding section 3 and a drive section 5. The shaft 4 is rotatably mounted in the metal housing 6.

The belt winding device 1 also comprises a main spiral spring 7 with an outer end 8 connected with a plastic housing 9. The plastic housing 9 is connected with the side of the metal housing 6 by three pins 10.

The inner end 11 of the main spiral spring 7 is rotatably connected with the drive section 5 of the shaft 4. The shaft 4 is thereby stressed in the winding direction a by the main spiral spring 7 when the shaft 4 rotates in the release direction b, ie when the belt 2 is released.

The belt winding device 1 also comprises a ratchet wheel 12 adjacent the main spiral spring 7 and coaxially arranged in the drive section 5 of the shaft 4, which ratchet wheel has a shaft 4. It can rotate in two directions of rotation with respect to the drive section 5 of the. The main spiral spring 7 side of the ratchet wheel 12 is provided with a disk 13 integrally formed with the ratchet wheel 12 for stability. The disk 13 has a central through opening 14 for the drive section 5 of the shaft 4. The ratchet wheel 12 is assigned a locking device 15 comprising a magnet actuator 16 with an actuated lifter 17 and a ratchet lever 18 pivotably mounted. The locking device 15 also comprises a spring 31 for the ratchet lever 18. The ratchet lever 18 interacts with teeth 19 provided around the outside of the ratchet wheel. The locking device is used to prevent the ratchet wheel 12 from rotating in the winding direction a. Rotation of the ratchet wheel 12 in the unwinding direction b is always possible. When the ratchet lever 18 is secured (engaged), the ratchet lever skips the tooth engagement portion 19 of the ratchet wheel 12.

Inside the ratchet wheel 12 a balance spring 20, also formed of a spiral spring, is arranged. The balance spring 20 is not connected to the ratchet wheel 12 in a positive locking manner, but abuts the inner circumference 21 of the ratchet wheel 12 through its outer winding. In order to increase the pressing force of the balance spring 20 against the inner circumference 21 of the ratchet wheel 12, a tension spring 22 formed of an annular spring piece is provided, which tension spring is provided inside the outer winding of the balance spring. It is arranged to press the outer winding of the balance spring 20 against the inner circumference 21 of the ratchet wheel 12. The outer end 23 of the balance spring 20 is bent inwardly in the form of a hook. The tension spring 22 is thereby fixed relative to the balance spring 20 in its circumferential position. The force transmission between the balance spring 20 and the ratchet wheel 12 is a friction formed by the balance spring 20 and the inner circumference 21 of the ratchet wheel 12 in both the winding direction (a) and the release direction (b). It is achieved by frictional engagement via the clutch.

Inside the balance spring 20 is provided a driven device 24 formed of a driven wheel. The driven device 24 comprises a plurality of teeth 25 extending radially while inclined in the release direction a. An accommodating portion 27 for driving the clutch section 28 of the balance spring 20 is formed in the flank 26 of the teeth 25 in the release direction (a). The clutch section 28 is formed by the inner end 29 of the balance spring 20. The inner end 20 is hooked and bent inward in the winding direction b. By means of the hook-shaped clutch section 28, a shape coupling between the teeth 25 or the flanks 26 of the driven wheel 24 and the balance spring 20 can be achieved. Since the shape coupling between the balance spring 20 and the follower device 24 can be separated by itself, the relative of the clutch section 28 to the winding direction a of the clutch section 28 with respect to the drive section 5 of the shaft 4. Exercise is possible. At this time, the inner end 29 of the balance spring 20 slides along the flat flank 30 of the tooth 25, which is opposite the flank 26.

When the shaft 4 rotates in the winding direction a, the balance spring 20 is moved from the retraction prevention clutch formed by the follower 24 and the balance spring 20 or the clutch section 28 of the balance spring 20. As the compressive stress is transmitted, the balance spring 20 exerts a rotational compressive stress on the drive section 5 of the shaft 4 in the release direction b.

The operation mode of the belt winding apparatus 1 is described below.

The main spiral spring 7 remains in engagement with the drive section 5 of the shaft 4 and the plastic housing 9 so that the shaft (by the main spiral spring 7) is pulled out by the main spiral spring 7 with the seat belt 2 pulled out. The compressive stress is continuously applied to the drive section 5 of 4) in the release direction a. When the seat belt 2 is fixed, the ratchet wheel 12 can freely rotate in the release direction a until the belt buckle (not shown) is locked. When the belt buckle is locked, the magnetic actuator 16 is actuated, whereby the actuating lifter 17 is retracted. As a result, the ratchet lever 18 connected with the actuating lifter 17 pivots to its locking position. In the locking position, the ratchet lever 18 interacts in a shape-fitting manner with the inclined flank of the teeth 19 of the ratchet wheel 12 to prevent rotation of the ratchet wheel 12 in the winding direction a. The ratchet wheel 12 can then rotate only in the release direction b by skipping the tooth engagement at the ratchet lever 18.

When the seat belt is wound, i.e. when the shaft 4 is rotated in the winding direction a by a force applied by the main spiral spring 7, it is formed integrally with the drive section 5 of the shaft 4 The driven device 24 also rotates in the winding direction a. The teeth 26 of the driven device 24 then follow the clutch section 28 of the balance spring 20 so that the balance spring 20 is pulled out when the ratchet wheel 12 is locked. At this time, as the torque required to pull the balance spring 20 acts against the torque of the main spiral spring 7, the torque of the main spiral spring 7 decreases by the torque required to pull the balance spring 20. This reduced torque acts on the shaft 4 and thus acts on the belt 2 in the winding direction a to provide the operator with the desired comfort effect.

If the operating range of the balance spring 20 is exceeded with the ratchet wheel 12 locked, that is, the rotation of the shaft 4 necessary to wind the seat belt 2 will result in the maximum possible total rotation of the balance spring 20. If exceeded, the balance spring may slide along the inner circumference 21 of the locked ratchet wheel 12 in the winding direction a. That is, the shaft 4 can continue to rotate in the winding direction a until the seat belt 2 is in contact with the driver's or passenger's body. Depending on the dimensional design of the tension spring 22, the static and kinetic friction between the outer circumference of the balance spring 20 and the inner circumference 21 of the ratchet wheel 12 can vary. The tension spring 22 is provided to produce a predetermined slip torque.

When the belt buckle is released, the actuating lifter 17 of the magnet actuator 16 is discharged outward, so that the ratchet lever 18 pivots radially against the elasticity of the spring 31 from its locking position. The ratchet wheel 12 is driven by the torque of the balance spring 20 and immediately starts to rotate in the winding direction a, at which time the balance spring 20 is relaxed. The ratchet wheel 12 is rotated at high speed in the winding direction a. At the latest, when the balance spring 20 is fully relaxed, the hooked clutch section 28 of the balance spring 20 is automatically disconnected from the corresponding receiving portion 27 of the follower 24 so that the ratchet wheel 12 can be completely stopped. Slip over the teeth 25 of the driven device 24 until The winding of the seat belt 2 is effected by the total torque of the main spiral spring 7 in a state where the ratchet wheel 12 is not locked.

Through the present invention, it is possible to provide a belt winding apparatus which can be manufactured at a low cost with reliability.

Claims (14)

Shaft 4, a main spiral spring 7 arranged to apply compressive stress to the shaft 4 in the winding direction a of the seat belt 2, relative to the shaft 4. The ratchet wheel 12 rotatably disposed, the locking device 15 for blocking the rotational movement (a) of the ratchet wheel 12 and the ratchet wheel 12 are locked. A belt winding device (1) comprising a balance spring (20) arranged so that a compressive stress that acts against the compressive stress of the main spiral spring (7) when transmitted to the shaft (4), The force transmission between the balance spring 20 and the ratchet wheel 12 is made in a friction coupling manner, Belt winding device. The method of claim 1, The ratchet wheel 12 has an inner circumference 21, the balance when the balance spring 20 is fully pulled and then the ratchet wheel 12 is locked and the shaft 4 rotates in the winding direction a. The spring 20 is arranged to slide along the inner circumference of the ratchet wheel 12, Belt winding device. The method according to claim 1 or 2, Tension spring 22 is provided to increase the pressing force of the balance spring 20 applied to the ratchet wheel 12, Belt winding device. The method of claim 3, wherein The tension spring 22 is inserted into two or more windings of the balance spring, Belt winding device. The method according to any one of claims 1 to 4, On the other hand, when the ratchet wheel 12 is locked, force is transmitted from the shaft 4 to the balance spring 20 in the winding direction a, and on the other hand, the ratchet wheel 12 is If it is not locked, a clutch is provided that allows the clutch section 28 of the balance spring 20 to make a relative rotational movement in the winding direction a with respect to the shaft 4. Belt winding device. The method of claim 5, The anti-retraction clutch includes a driven device 24 rotatably coupled to the shaft 4, and is self-separating between the driven device 24 and the clutch section 28 of the balance spring 20. Possible shape locking can be formed, Belt winding device. The method of claim 6, The driven device 24 is designed as a driven wheel with at least one receptacle 27 for hooking the balance spring 20 to be detachable. Belt winding device. The method of claim 7, wherein The receiving portion 27 is formed of teeth 25 extending radially around the driven wheel, Belt winding device. The method of claim 8, The teeth 25 are inclined in the winding direction (a), Belt winding device. The method according to any one of claims 1 to 9, The balance spring 20 is a spiral spring, Belt winding device. The method according to any one of claims 5 to 10, A clutch section 28 of the balance spring 20 is formed from the inner end 29 of the balance spring 20 to form a shape engagement with the follower 24. Belt winding device. The method according to any one of claims 5 to 11, The clutch section 28 of the balance spring 20 is formed in a hook shape, Belt winding device. The method according to any one of claims 1 to 12, The shaft 4 is formed so as to be able to be coupled to each other in several parts in the axial direction, in particular, Belt winding device. The method according to any one of claims 6 to 13, The driven device 24 is integrally formed with the shaft 4 or with parts 3, 5 of the shaft, Belt winding device.

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