JP5263626B2 - 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 rotating member that rotates with the spindle and has an engaged portion on the peripheral surface;
A rotatable engaging member having an engaging portion engageable with an engaged portion of the rotating member;
An engaging member rotating shaft for rotatably holding the engaging member;
A guide for guiding the rotation of the engaging member;
An engagement member holding body capable of engaging with the engagement member rotation shaft and holding the engagement member;
With
The engaging member holding body is held by a frictional force on a non-driven portion of the case member,
When the engaging member rotation shaft moves in a direction relatively opposite to the direction in which the seat belt is wound, the engaging portion follows the guide portion in a direction in which the engaging portion engages with the engaged portion of the rotating member. rotated Te,
The engagement member holding body is a substantially ring-shaped friction spring,
The friction spring is held with its inner peripheral surface or outer peripheral surface in contact with the convex portion of the case member by its own biasing force,
The engaging member rotation shaft has an outer peripheral surface formed in an eccentric shape,
When the engaging portion of the engaging member is engaged with the engaged portion of the rotating member, the friction spring is deformed by the outer peripheral surface of the engaging member rotating shaft, and the convex portion of the case member is A retractor for a seat belt, characterized by reducing frictional force .

( 2 ) The engaging member rotating shaft is held by the non-driving portion of the case member by a frictional force when the power of the electric actuator starts to be transmitted in the direction of winding the seat belt. The retractor for a seat belt according to any one of (1) , wherein the seat belt moves in a direction opposite to a direction in which the seat belt is wound up by a holding body.

( 3 ) The seat belt retractor according to (1) or (2) , wherein the guide portion is provided on a plate member fixed to a final gear that transmits power of the electric actuator.

( 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 that is rotated by power from the electric actuator;
A rotating member that rotates with the spindle and has an engaged portion on the peripheral surface;
A rotatable engaging member having an engaging portion engageable with an engaged portion of the rotating member;
An engaging member rotating shaft for rotatably holding the engaging member;
An engaging member holding body capable of rotatably engaging the engaging member rotating shaft and being held by a non-driving portion of the case member by its urging force, and holding the engaging member;
Provided on a plate member fixed to the final gear, from when the final gear starts to rotate in the seat belt winding direction until the engaging portion of the engaging member engages with the engaged portion of the rotating member A guide for guiding the rotation of the engaging member in a predetermined angle range;
Equipped with a,
When the final gear starts to rotate in the seat belt winding direction, the engaging member rotates along the guide portion,
When the final gear rotates more than a predetermined angle in the seat belt winding direction, the engaging portion of the engaging member engages with the engaged portion of the rotating member, and the final gear, the plate member, engagement member holding member, and said engaging member is rotated integrally with the seat belt retractor according to claim Rukoto power from the electric actuator is transmitted to the spindle.

(5) The engaging member rotation shaft has an outer circumferential surface formed in an eccentric shape, and rotates with the rotation of the engagement member.
When the engaging portion of the engaging member is engaged with the engaged portion of the rotating member, the engaging member holding body is deformed by the outer peripheral surface of the engaging member rotating shaft, and the case member is not The retractor for a seat belt according to (4) , wherein a frictional force to be held by the drive portion is reduced.
(6) 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 final gear that is rotated by power from the electric actuator;
A rotating member that rotates with the spindle and has an engaged portion on the peripheral surface;
A rotatable engaging member having an engaging portion engageable with an engaged portion of the rotating member;
A guide for guiding the rotation of the engaging member;
An engagement member holding body capable of engaging with the engagement member rotation shaft and holding the engagement member;
With
The engaging member holding body is held by a frictional force on a non-driven portion of the case member,
The engagement member rotation shaft in a predetermined angle range from when the final gear starts to rotate in the seat belt winding direction until the engagement portion of the engagement member engages with the engaged portion of the rotation member. Is moved along the guide portion in the direction in which the engaging portion engages with the engaged portion of the rotating member when the seat belt moves in a direction opposite to the winding direction of the seat belt,
When the final gear rotates more than a predetermined angle in the seat belt winding direction, the engaging portion of the engaging member engages with the engaged portion of the rotating member, and the final gear and the engaging member are held. A retractor for a seat belt, wherein the body and the engaging member rotate integrally, and the power from the electric actuator is transmitted to the spindle.

  According to the seat belt retractor of the present invention, the engaging member holding body that engages with the engaging member rotating shaft is held by the frictional force on the non-driving portion of the case member, and the engaging member rotating shaft is the seat belt When moving in a direction opposite to the winding direction, the engaging portion rotates along the guide portion in a direction to engage with the engaged portion of the rotating member. This makes it possible to perform 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 middle 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 seatbelt retractor according to a modification of the present embodiment, (a) is a diagram for explaining the state of the pawl rotation shaft and the friction spring in the non-engagement state of the clutch, (b), It is a figure for demonstrating the state of the pawl rotation axis | shaft and friction spring in the engagement state of a clutch.

Explanation of symbols

10 Retractor for seat belt 12 Spindle 17 Power transmission mechanism 34 Motor (electric actuator)
42 Friction spring (engaging member holder)
46 Ring plate (plate member)
48 pawl rotating shaft (engaging member rotating shaft)
49 Paul (engagement member)
49c engaging part 50 latch ring (rotating member)
50a External tooth (engaged part)
52 Clutch

  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. As shown in FIGS. 1 and 2, the clutch 52 includes a friction spring 42 that is an engagement member holding body, a ring plate 46 that is a plate member, a final gear 47, a pawl 49 that is an engagement member, and a rotation of the engagement member. A pawl rotating shaft 48 as a shaft, a latch ring 50 as a rotating member, and a bush 51 are included.

  The latch ring 50 is coupled with a joint 22 and an internal tooth (not shown) integrally attached to the spindle 12 and rotates integrally with the spindle 12, and an external tooth which is an engaged portion on the outer peripheral surface. 50a (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 pawl 49 is formed integrally with a pawl rotation shaft 48 provided at an intermediate portion thereof, and rotates around the rotation shaft 48. The pawl 49 has an engaging portion 49c that engages with the external teeth 50a of the latch ring 50 at the tip (see FIG. 3).

  The friction spring 42 has a substantially ring shape in which both ends are partially open, and the outer peripheral surface of the convex portion 25a that is a non-driving portion formed on the lower cover 25 is directed toward the center of the rotation axis of the spindle 12 by its own urging force. The projection 25a is urged to be held in contact. As a result, when the friction spring 42 receives a force in the rotational direction, it generates a frictional force in the direction opposite to the rotational direction between the convex portion 25a of the lower cover 25 and the circumferential direction with respect to the ring plate 46. Movement is restricted. The convex portion 25a protrudes in the axial direction from the side surface of the case, and is formed concentrically with the central hole 25b through which the joint 22 passes.

  A shaft engaging portion 42 a that engages with the rotating shaft 48 so as to surround the pawl rotating shaft 48 is formed by bending at an intermediate portion of the friction spring 42.

  Further, a part of the ring plate 46 in the circumferential direction includes a cam surface 46a that is a guide portion that guides the outer peripheral surface of the pawl 49 on the engagement portion 49c side inward in the radial direction, and is opposed to the cam surface 46a. A release surface 46b for guiding the inner peripheral surface of the pawl 49 is formed. The cam surface 46 a is configured by a curved wall surface that comes into contact with the outer peripheral surface of the tip end of the pawl 49 when the engaging portion 49 c engages with the external teeth 50 a of the latch ring 50. Further, the release surface 46b is constituted by a wall surface that comes into contact with the inner peripheral surface of the pawl 49 when the engaging portion 49c releases the engagement with the external teeth 50a.

  Therefore, a predetermined angle range (9 in the present embodiment) from when the final gear 47 starts to rotate in the seat belt winding direction until the engaging portion 49c of the pawl 49 engages with the engaged portion 50a of the latch ring 50. )), The pawl 49 is restricted by the friction spring 42 to rotate together with the final gear 47 and is guided by the cam surface 46a of the rotating ring plate 46 so as to engage with the engaging portion 50a of the latch ring 50. Rotate.

  After the final gear 47 rotates in the seat belt winding direction over a predetermined angle range and the engaging portion 49c of the pawl 49 engages with the engaged portion 50a of the latch ring 50, the final gear 47, the ring The plate 46, the friction spring 42, and the pawl 49 rotate integrally.

  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 pawl 49 has a release surface in a state where the pawl rotating shaft 48 is engaged by the engaging portion 42 a of the friction spring 42. The engaging portion 49c is guided by 46b and is away from the latch ring 50, and the latch ring 50 and the pawl 49 are not engaged. 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 the winding side, the final gear 47 geared to the rotation shaft of the motor 34 rotates counterclockwise (see arrow A in FIG. 4). At this time, the pawl 49 integrally formed with the rotating shaft 48 is urged by the friction spring 42 and tries to stay there. Therefore, the pawl rotating shaft 48 moves relative to the final gear 47 in a direction opposite to the direction in which the seat belt is wound up.

  On the other hand, since the ring plate 46 having the cam surface 46a rotates together with the final gear 47, the pawl 49 rotates about the rotation shaft 48 along the cam surface 46a in the rotation center direction.

  Then, as shown in FIG. 5, when the final gear 47 rotates by a predetermined angle (9 ° in this embodiment), the engaging portion 49 c of the pawl 49 completes the engagement with the external teeth 50 a of the latch ring 50. To do.

  When the final gear further rotates beyond a predetermined angle in the seat belt winding direction, the final gear 47, the ring plate, and the engagement portion 49c of the pawl 49 and the external teeth 50a of the latch ring 50 are engaged. 46, the friction spring 42, and the pawl 49 rotate integrally, and the power from the electric actuator is transmitted to the spindle 12.

  When the motor 34 rotates to the release side, the final gear 47 rotates clockwise. In this case, the pawl 49 is guided by the release surface 46b formed on the ring plate 46, and the engaging portion 49c of the pawl 49 is separated from the external teeth 50a of the latch ring 50 and is pushed back to the original position.

  According to the seatbelt retractor 10 described above, the clutch 52 rotates together with the spindle 12, and the latch ring 50 having the external teeth 50 a on the outer peripheral surface, and the engagement engageable with the external teeth 50 a of the latch ring 50. A pawl 49 having a portion 49a, a pawl rotating shaft 48 for rotatably holding the pawl 49, a cam surface 46a for guiding the pawl 49 to rotate, and a pawl rotating shaft 48 are engaged. And a friction spring 42 capable of holding the pawl. The friction spring 42 is held by the frictional force on the convex portion 25a of the lower cover 25, and when the pawl rotating shaft 48 moves in a direction opposite to the direction in which the seat belt is wound, the engaging portion 49c is latched. It rotates along the cam surface 46a in a direction to engage with the 50 external teeth 50a. This makes it possible to perform a good clutch operation with a small number of parts.

  Further, the ring-shaped friction spring 42 urged toward the center of the rotation axis of the spindle 12 is held by the convex portion 25a of the lower cover 25, so that the friction force is applied with a simpler structure. Is done.

  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-described embodiment, the friction spring 42 is held on the outer peripheral surface of the convex portion 25a of the lower cover 25 by the urging force in the center of the rotation axis.
The friction spring 42 may be held by an urging force spreading in the radial direction on the inner peripheral surface of the convex portion 25a.

  Further, as shown in FIG. 6, the outer peripheral surface of the pawl rotation shaft 48 may be formed in an eccentric shape having a protruding portion 48a partially. When the engaging portion 49c of the pawl 49 engages with the external teeth 50a of the latch ring 50, the pawl rotating shaft 48 rotates with the rotation of the pawl 49. 48a contacts the shaft engaging part 42a of the friction spring 42, and the friction spring 42 is deformed so as to be spread (see FIG. 6B). For this reason, the pressing force of the friction spring 42 against the convex portion 25a of the lower cover 25 is reduced, and the frictional force between the friction spring 42 and the convex portion 25a is reduced. As a result, the friction spring 42 rotates while maintaining good slidability with the convex portion 25a.

  It should be noted that the friction until the tooth tip of the engaging portion 49c of the pawl 49 enters the inside of the tooth tip diameter of the external tooth 50a of the latch ring 50, that is, until the engagement of these teeth is determined. The phases of the protruding portion 48a of the pawl rotating shaft 48 and the engaging portion 49c of the pawl 49 are set so that the spring 42 is not spread.

  This application is based on a Japanese patent application (Japanese Patent Application No. 2007-221596) filed on Aug. 28, 2007, the contents of which are incorporated herein by reference.

Claims (6)

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 and has an engaged portion on the peripheral surface;
A rotatable engaging member having an engaging portion engageable with an engaged portion of the rotating member;
An engaging member rotating shaft for rotatably holding the engaging member;
A guide for guiding the rotation of the engaging member;
An engagement member holding body capable of engaging with the engagement member rotation shaft and holding the engagement member;
With
The engaging member holding body is held by a frictional force on a non-driven portion of the case member,
When the engaging member rotation shaft moves in a direction relatively opposite to the direction in which the seat belt is wound, the engaging portion follows the guide portion in a direction in which the engaging portion engages with the engaged portion of the rotating member. rotated Te,
The engagement member holding body is a substantially ring-shaped friction spring,
The friction spring is held with its inner peripheral surface or outer peripheral surface in contact with the convex portion of the case member by its own biasing force,
The engaging member rotation shaft has an outer peripheral surface formed in an eccentric shape,
When the engaging portion of the engaging member is engaged with the engaged portion of the rotating member, the friction spring is deformed by the outer peripheral surface of the engaging member rotating shaft, and the convex portion of the case member is A retractor for a seat belt, characterized by reducing frictional force . The engaging member rotating shaft is supported by the engaging member holding body that is held by a frictional force on the non-driven portion of the case member when the power of the electric actuator starts to be transmitted in the direction of winding the seat belt. The seatbelt retractor according to claim 1, wherein the seatbelt retractor moves in a direction opposite to a direction in which the seatbelt is wound up. The guide portion is a seat belt retractor according to claim 1 or 2, characterized in that provided in the plate member fixed to the final gear that transmits power of the electric actuator. 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 that is rotated by power from the electric actuator;
A rotating member that rotates with the spindle and has an engaged portion on the peripheral surface;
A rotatable engaging member having an engaging portion engageable with an engaged portion of the rotating member;
An engaging member rotating shaft for rotatably holding the engaging member;
An engaging member holding body capable of rotatably engaging the engaging member rotating shaft and being held by a non-driving portion of the case member by its urging force, and holding the engaging member;
Provided on a plate member fixed to the final gear, from when the final gear starts to rotate in the seat belt winding direction until the engaging portion of the engaging member engages with the engaged portion of the rotating member A guide for guiding the rotation of the engaging member in a predetermined angle range;
Equipped with a,
When the final gear starts to rotate in the seat belt winding direction, the engaging member rotates along the guide portion,
When the final gear rotates more than a predetermined angle in the seat belt winding direction, the engaging portion of the engaging member engages with the engaged portion of the rotating member, and the final gear, the plate member, engagement member holding member, and said engaging member is rotated integrally with the seat belt retractor according to claim Rukoto power from the electric actuator is transmitted to the spindle. The engaging member rotation shaft has an outer peripheral surface formed in an eccentric shape, and rotates together with the rotation of the engaging member.
When the engaging portion of the engaging member is engaged with the engaged portion of the rotating member, the engaging member holding body is deformed by the outer peripheral surface of the engaging member rotating shaft, and the case member is not The retractor for a seat belt according to claim 4 , wherein a frictional force to be held by the drive portion is reduced. 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 that is rotated by power from the electric actuator;
A rotating member that rotates with the spindle and has an engaged portion on the peripheral surface;
A rotatable engaging member having an engaging portion engageable with an engaged portion of the rotating member;
A guide for guiding the rotation of the engaging member;
An engagement member holding body capable of engaging with the engagement member rotation shaft and holding the engagement member;
With
The engaging member holding body is held by a frictional force on a non-driven portion of the case member,
The engagement member rotation shaft in a predetermined angle range from when the final gear starts to rotate in the seat belt winding direction until the engagement portion of the engagement member engages with the engaged portion of the rotation member. Is moved along the guide portion in the direction in which the engaging portion engages with the engaged portion of the rotating member when the seat belt moves in a direction opposite to the winding direction of the seat belt,
When the final gear rotates more than a predetermined angle in the seat belt winding direction, the engaging portion of the engaging member engages with the engaged portion of the rotating member, and the final gear and the engaging member are held. A retractor for a seat belt, wherein the body and the engaging member rotate integrally, and the power from the electric actuator is transmitted to the spindle.

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