JP5451859B2 - Seat belt retractor - Google Patents

Description

  The present invention relates to a seat belt retractor, and more particularly to a seat belt retractor including an electric actuator using a motor.

In a conventional seat belt retractor, a sudden deceleration state of a vehicle is detected by a sensor, and a spindle is rotated in a winding direction by a motor. When there is a possibility of a collision, the seat belt (webbing) is wound around a certain amount to restrain the occupant lightly, and at the time of the collision, the restraining force is increased to hold the occupant securely (for example, patent Reference 1 and 2).

  In the seatbelt retractors described in Patent Documents 1 and 2, in the power transmission mechanism that transmits the power from the electric actuator to the spindle, a clutch is interposed to prevent the rotation from the spindle side from being transmitted to the electric actuator. Yes.

  The clutch described in Patent Document 1 includes a gear wheel and a rotor that rotate by transmission of rotation of an electric actuator. The rotor is supported by a pawl that is constantly urged in the direction of engagement with the spindle by an urging member, and this pawl is normally held in a disengaged position from the spindle by a holding member provided on the rotor. Has been. When the rotor is rotated about one axis by the driving force of the motor, the holding of the pawl by the holding member is released, and the pawl is engaged with the spindle by the urging force of the urging member. Thereby, the rotation of the rotor is transmitted to the spindle and the spindle rotates. On the other hand, when the rotor rotates around the axis to the other, the holding member moves and holds the pawl to the disengagement position with the spindle against the urging force of the urging member.

  In addition, the holding member and the pawl form an inclined surface that generates a drag force in the separation direction so as to maintain the mutual holding state in a state where the rotor is stopped, thereby preventing erroneous clutch engagement.

JP 2006-103657 A JP 2004-42782 A

  By the way, in the seat belt retractor, the pawl is urged and rotated in the direction of coupling with the motor by a torsion spring or a leaf spring. For this reason, when an impact is applied from the outside, the urging force to the pawl is weakened by this impact, and there is a possibility that the operation is delayed and a malfunction occurs. In addition, the clutch has a large number of parts, and there is a problem that assembly work is complicated.

  The present invention has been made in view of the above-described circumstances, and it is an object of the present invention to provide a seatbelt retractor capable of performing a good clutch operation with a small number of parts.

The above object of the present invention is achieved by the following configurations.
(1) a spindle for winding up a seat belt;
An electric actuator that generates power to rotate the spindle;
A power transmission mechanism capable of transmitting power from the electric actuator to the spindle;
A seat belt retractor comprising:
The power transmission mechanism is
A final gear for transmitting the power of the electric actuator;
A friction spring disposed around a rotating member that rotates together with the spindle, one end fixed to the final gear side, and the other end held by a case member so as to generate a resistance force when rotating;
A clutch having
When the clutch is off, a gap is secured between the friction spring and the rotating member.
During the operation of the clutch, the final gear and the rotating member rotate together via the friction spring by the resistance generated by the friction spring rotating relative to the case member. A retractor for seat belts.

(2) The retractor for a seat belt according to (1), wherein the friction spring is wound around the rotating member during the clutch operation.

(3) The seat belt retractor according to (1) or (2), wherein the friction spring is a coil spring.

(4) a spindle for winding up the seat belt;
An electric actuator that generates power to rotate the spindle;
A power transmission mechanism capable of transmitting power from the electric actuator to the spindle;
A seat belt retractor comprising:
The power transmission mechanism is
A rotating member that rotates with the spindle;
A final gear for transmitting the power of the electric actuator;
It is arranged between the peripheral surface of the boss part of the case member and the peripheral surface of the rotating member, one end is fixed to the final gear side, and the other end is held by the case member so as to generate a resistance force when rotating. Friction spring,
A clutch having
When the clutch is off, a gap is secured between the friction spring and the rotating member.
During the operation of the clutch, the friction spring is engaged with the peripheral surface of the rotating member by the resistance generated by the friction spring rotating relative to the case member, and the final gear is engaged. A seatbelt retractor wherein the rotating member and the rotating member rotate together via the friction spring.

  According to the seatbelt retractor of the present invention, the clutch is disposed around the rotating member that rotates together with the spindle, one end is fixed to the final gear side, and the other end generates a resistance force when rotating. When the clutch is in an off state, a clearance is secured between the friction spring and the rotating member. When the clutch is operated, the friction spring rotates relative to the case member. Due to the resistance generated by the movement, the radius of the friction spring becomes smaller than that before the clutch operation, and the final gear and the rotating member rotate integrally via the friction spring. This eliminates the need for a conventional pawl and allows a good clutch operation with a small number of parts.

  According to the seatbelt retractor of the present invention, the clutch is disposed between the boss portion peripheral surface of the case member and the peripheral surface of the rotating member, one end is fixed to the final gear side, and the other end is rotated. A friction spring that is held by the case member so as to generate a resistance force, and when the clutch is in an off state, a clearance is secured between the friction spring and the rotating member. Because of the resistance force generated by the friction spring rotating relative to the case member, the radius of the friction spring is changed from the radius before the clutch is operated, and the friction spring engages with the peripheral surface of the rotating member. Thus, the final gear and the rotating member rotate together via the friction spring. This also eliminates the need for a conventional pawl and allows a good clutch operation with a small number of parts.

It is a disassembled perspective view of the retractor for seatbelts concerning this invention. It is sectional drawing which shows the structure in the gear case of FIG. It is a figure for demonstrating the non-engagement state of the clutch which transmits the motive power from a motor. It is a figure for demonstrating the engagement state of the clutch which transmits the motive power from a motor. It is a figure for demonstrating the non-engagement state of the clutch which transmits the motive power from a motor in the retractor for seatbelts concerning the modification of this invention. FIG. 6 is a diagram for explaining an engagement state of a clutch for transmitting power from a motor in the seat belt retractor of FIG. 5.

  Next, a seatbelt retractor according to an embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, a seat belt retractor 10 of this embodiment includes a spindle 12 that winds up a seat belt (not shown), and a winding spring device 13 that biases the spindle 12 in the seat belt winding direction. A lock mechanism 14 that locks the seat belt pull-out operation in accordance with acceleration detected by an acceleration sensor (not shown), a motor 34 that is an electric actuator that generates power for rotating the spindle 12, and a motor 34 And a power transmission mechanism 17 capable of transmitting the power to the spindle 12.

  Both ends of the spindle 12 are rotatably supported by the support frame 11. Further, a torsion bar (not shown) constituting an energy absorption mechanism is provided in the spindle 12.

  Further, a lower cover 25 and an upper cover 53 that are case members are attached to the left side surface of the support frame 11 in the drawing with a screw 27 via a bearing ring 24. A space for accommodating the power transmission mechanism 17 is formed between the lower cover 25 and the upper cover 53 attached thereto.

  A motor assembly 16 is attached to a lower portion of the lower cover 25, that is, a position below the support frame 11. The motor assembly 16 includes a rear cap 31, a printed circuit board 32, a rear case 33, a motor 34, an O-ring 37, a first gear 35, and a front case 36. The first gear 35 is attached to the rotating shaft of the motor 34, is inserted into the lower cover 25, and meshes with the second gear 54 of the torque limiter mechanism 19 provided in the power transmission mechanism 17.

  The torque limiter mechanism 19 includes a third small gear 59 that meshes with the fourth gear 58, a spring holder 55 that is rotatably attached to the third small gear 59, and a plurality of limit springs 56 that are held by the spring holder 55. And a third large gear 57 which is arranged coaxially with the third small gear 59 and meshes with the second gear 54. While the limit spring 56 is held by the spring holder 55, one end is engaged with an uneven surface (not shown) formed on the inner peripheral surface of the third large gear 57 and elastically deformed to form a third. The relative rotation of the large gear 57 with respect to the third small gear 59 is allowed.

  For this reason, in the torque limiter mechanism 19, the third large gear 57 and the third small gear 59 are rotated in the same direction while maintaining a relative phase by the limit spring 56 in the normal state. Here, at the time of winding by driving the motor 34, a torque difference larger than a predetermined value is caused between the third large gear 57 and the third small gear 59 due to a light collision or braking that the pretensioner mechanism 15 does not operate. When this occurs, the engagement between the one end of the limit spring 56 and the uneven surface of the third large gear 57 is released, and slipping starts while elastically deforming. As a result, transmission of excessive torque by the motor 34 can be suppressed, the gear teeth can be prevented from being damaged, and the influence on the restraint performance during the energy absorbing operation can be reduced. In the present embodiment, the first gear 35, the second gear 54, the third small gear 59, the third large gear 57, the fourth gear 58, and a final gear 47, which will be described later, constitute a gear assembly.

  Further, a clutch 52 constituting the power transmission mechanism 17 is accommodated in the upper part between the lower cover 25 and the upper cover 53. The clutch 52 includes a friction spring 42, a ring plate 46 that is a plate member, a final gear 47, a pin member 48, a latch ring 50 that is a rotating member, and a bush 51.

  The latch ring 50 is coupled to a joint 22 integrally attached to the spindle 12 by an internal tooth (not shown) and rotates integrally with the spindle 12. The latch ring 50 is opposed to the inner peripheral surface of the friction spring 42. The spring 42 has an outer peripheral surface 50a that contacts and engages by reducing the diameter (see FIG. 3).

  The final gear 47 is arranged coaxially with the latch ring 50 and is gear-coupled to the rotating shaft of the motor 34. The ring plate 46 is attached to the final gear 47 and rotates integrally with the final gear 47. The pin member 48 is inserted and fixed in a pin hole 46 a formed in the ring plate 46 and rotates integrally with the final gear 47. The pin member 48 may be indirectly fixed to the final gear 47 through the ring plate 46 as in the present embodiment, or may be directly fixed to the final gear 47.

  The friction spring 42 is a coil spring made of stainless steel wire (SUS304-WPB in the present embodiment), and is a boss formed with one end 42 a bent and fixed to the pin member 48 and the other end 42 b formed on the lower cover 25. It is held on the inner peripheral surface of the portion 25a. In the free state, the other end 42b of the friction spring 42 extends so as to be located outside the circular portion formed by the body portion 42c, and is wound and accommodated within the inner peripheral surface of the boss portion 25a. Thus, a resistance force is generated during rotation. In this clutch-off state, a gap (0.8 mm in this embodiment) is secured between the inner peripheral surface of the body portion of the friction spring 42 and the outer peripheral surface 50a of the latch ring 50, and the belt is wound up. Sometimes the components of the clutch 52 have no effect. The boss portion 25a of the lower cover 25 protrudes in the axial direction from the side surface of the case and is formed concentrically with the center hole 25b through which the joint 22 passes.

  Accordingly, the friction spring 42 is fixed to the pin member 48 on the final gear side while the final gear 47 rotates from the start of rotation in the seat belt winding direction to a predetermined angle range (9 ° in this embodiment). When the one end 42a moves in the winding direction, the predetermined radius of the barrel portion 42c is gradually reduced, the outer peripheral surface of the barrel portion is separated from the inner peripheral surface of the boss portion 25a, and the outer peripheral surface 50a of the latch ring 50 is obtained. It is comprised so that it may be wound around.

  When the final gear 47 rotates in the seat belt retracting direction over a predetermined angle range, the friction spring 42 is reduced in diameter and wound around the outer peripheral surface 50a of the latch ring 50, so that the final gear 47 and the latch ring 50 are in friction. It rotates integrally through the spring 42.

  Next, the operation of the seatbelt retractor 10 of this embodiment will be described. When the possibility of a collision is detected by a monitoring sensor (not shown) or the like, the motor 34 is driven before the collision by an ECU (not shown), and the spindle 12 is rotated via the power transmission mechanism 17 to wind the seat belt. When the possibility of the collision is lost, the motor 34 is reversed to return to the state before the collision.

Here, the operation of the clutch 52 will be described with reference to FIGS.
First, as shown in FIG. 3, when the winding by the motor 34 is not performed, the friction spring 42 is wound and held in the inner peripheral surface of the boss portion 25 a of the case member 25, and The latch ring 50 and the friction spring 42 are disengaged from each other. For this reason, only the latch ring 50 integrated with the spindle 11 can be rotated, and the seat belt can be normally wound and pulled out.

  As shown in FIG. 4, when the motor 34 rotates to a winding side by a predetermined angle (9 ° in this embodiment), the final gear 47 that is gear-coupled to the rotating shaft of the motor 34 rotates counterclockwise. To do. At this time, since one end 42a of the friction spring 42 supported by the pin member 48 fixed to the final gear 47 also rotates counterclockwise, the radius of the body portion 42c of the friction spring 42 becomes predetermined before the clutch operation due to elastic deformation. And wrap around the outer peripheral surface 50a of the latch ring 50.

  Then, when the final gear 47 further rotates beyond a predetermined angle in the seat belt winding direction, the final gear 47 and the latch ring 50 rotate together with the friction spring 42 wound around the outer peripheral surface 50a of the latch ring 50. The power from the motor 34 is transmitted to the spindle 12.

  When the motor 34 rotates to the release side, the final gear 47 rotates clockwise. In that case, one end of the friction spring 42 fixed to the pin member 48 also moves in the clockwise direction only, moves away from the outer peripheral surface 50a of the latch ring 50, and is held on the inner peripheral surface of the boss portion 25a of the lower cover 25. .

  According to the seatbelt retractor 10 described above, the clutch 52 is fixed directly or indirectly to the final gear 47 that transmits the power of the motor 34, and the pin member 48 that rotates integrally with the final gear 47; A friction spring 42 disposed around a latch ring 50 that rotates together with the spindle 12, one end 42 a is fixed to the pin member 48, and the other end 42 b is held by the lower cover 25 so as to generate a resistance force when rotating. Have. The radius of the friction spring 42 becomes smaller than the predetermined radius before the clutch is operated due to the resistance generated by the friction spring 42 rotating relative to the lower cover 25 during the operation of the clutch 52. As a result, the friction spring 42 is engaged with the outer peripheral surface 50a of the latch ring 50, and the power of the motor 34 can be transmitted to the spindle 12 via the friction spring 42 without providing a conventional pawl. It is possible to perform a good clutch operation.

  Since the friction spring 42 is wound around the latch ring 50 during the clutch operation, the power of the motor 34 can be transmitted to the spindle 12 with a simpler structure during the clutch operation.

  The seat belt retractor described above is a preferable example of the present invention, and other embodiments can be implemented or performed by various methods. The invention is not limited to the detailed shape, size, configuration, and the like of the components shown in the accompanying drawings unless otherwise specified in the present specification. In addition, expressions and terms used in the present specification are for the purpose of explanation, and are not limited thereto unless otherwise specified.

  For example, in the above embodiment, the friction spring 42 is held on the inner peripheral surface of the boss portion 25a of the lower cover 25, and has a structure in which the diameter is reduced during the clutch operation and wound around the outer peripheral surface of the latch ring 50. It is not limited to this, but is disposed between the peripheral surface of the boss portion 25a of the lower cover 25 and the peripheral surface of the latch ring 50, one end 42a is fixed to the pin member 48, and the other end 42b exerts a resistance force during rotation. The friction spring 42 is held by the lower cover 25 so as to be generated, and a resistance force generated by the friction spring 42 rotating relative to the lower cover 25 during the operation of the clutch causes the radius of the friction spring 42 to be a radius before the operation of the clutch. The friction spring 42 may be engaged with the peripheral surface of the latch ring 50.

  5 and 6, the friction spring 42 'is disposed between the outer peripheral surface of the boss portion 25a of the lower cover 25 and the inner peripheral surface 50b of the latch ring 50, and one end 42a is a pin. It is fixed to the member 48, and the other end 42b is held on the outer peripheral surface of the boss portion 25a of the lower cover 25 so as to generate a resistance force when rotating. The radius of the friction spring 42 becomes larger than that before the operation of the clutch 52 due to the resistance generated when the friction spring 42 rotates relative to the lower cover 25 during the operation of the clutch 52, and the friction spring 42 is It sticks to and engages with the inner peripheral surface 50b of the latch ring 50. In order to increase the diameter of the friction spring 42 more reliably, a weight may be attached to the end portion or a means for preventing slipping may be provided.

10 Retractor for seat belt 12 Spindle 17 Power transmission mechanism 34 Motor (electric actuator)
42 Friction spring 46 Ring plate (plate member)
48 Pin member 50 Latch ring (Rotating member)
50a outer peripheral surface 52 clutch

Claims (4)

A spindle that winds up the seat belt;
An electric actuator that generates power to rotate the spindle;
A power transmission mechanism capable of transmitting power from the electric actuator to the spindle;
A seat belt retractor comprising:
The power transmission mechanism is
A final gear for transmitting the power of the electric actuator;
A friction spring disposed around a rotating member that rotates together with the spindle, one end fixed to the final gear side, and the other end held by a case member so as to generate a resistance force when rotating;
A clutch having
When the clutch is off, a gap is secured between the friction spring and the rotating member.
During the operation of the clutch, the final gear and the rotating member rotate together via the friction spring by the resistance generated by the friction spring rotating relative to the case member. A retractor for seat belts.   The seat belt retractor according to claim 1, wherein the friction spring is wound around the rotating member during the clutch operation.   The seat belt retractor according to claim 1, wherein the friction spring is a coil spring. A spindle that winds up the seat belt;
An electric actuator that generates power to rotate the spindle;
A power transmission mechanism capable of transmitting power from the electric actuator to the spindle;
A seat belt retractor comprising:
The power transmission mechanism is
A rotating member that rotates with the spindle;
A final gear for transmitting the power of the electric actuator;
It is arranged between the peripheral surface of the boss part of the case member and the peripheral surface of the rotating member, one end is fixed to the final gear side, and the other end is held by the case member so as to generate a resistance force when rotating. Friction spring,
A clutch having
When the clutch is off, a gap is secured between the friction spring and the rotating member.
During the operation of the clutch, the friction spring is engaged with the peripheral surface of the rotating member by the resistance generated by the friction spring rotating relative to the case member, and the final gear is engaged. A seatbelt retractor wherein the rotating member and the rotating member rotate together via the friction spring.

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