JPH0982171A - Seatbelt winding amount detecting switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive seatbelt winding amount detecting switch that has high operational reliability by having a sliding contact which moves following changes in a webbing diameter and a fixed contact which switches the connected state of a circuit from one to the other when the amount of movement of the sliding contact has reached a predetermined amount. SOLUTION: Changes in the diameter of webbing wound on the winding shaft of the seatbelt retractor of a seatbelt winding amount detecting switch 1 are transmitted to a movable element 12, and when the amount of movement of the movable element 12 has reached a predetermined amount, fixed contacts 15, 16 provided on the interior wall of a cylinder part 10 facing a path of travel come into contact with a sliding contact 14 fixed to the movable element 12, so as to detect the changes. The contact between the contacts 15, 16 and 14 are not via the operation of plural parts, so variations in the amount of movement of the contact 14 due to the accumulation of variations in the molding and mounting accuracies of operating parts can be avoided. Therefore, the positions where the contacts come into contact with each other can be set with high accuracy, and the detecting accuracy can be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seatbelt winding amount detection switch for detecting the winding amount of webbing wound around a take-up shaft of a seatbelt retractor. The present invention relates to improvements for realizing improvement in detection accuracy, operation reliability, and the like.

[0002]

2. Description of the Related Art Conventionally, a retractor is wound around a retractor winding shaft for controlling an electric circuit for warning that a seat belt is forgotten to be tightened and for controlling an operation of a lock mechanism provided in a seat belt retractor. Various seat belt winding amount detection switches for detecting the winding amount of the webbing have been proposed.

For example, in the safety belt pull-out detection switch device disclosed in Japanese Utility Model Laid-Open No. 48-49724, a contact that swings in response to a change in the webbing winding diameter on the winding shaft of the retractor is commercially available. Is a type that turns on and off the micro switch actuator. Further, in U.S. Pat. No. 4,163,880, a lever arm that swings in response to a change in webbing winding diameter on a bobbin causes elastic displacement in a contact terminal formed by press molding a metal plate, When the displacement amount of the contact terminal reaches a predetermined amount, the contact portion at the tip of the contact terminal makes electrical contact with the fixed contact that is fixedly arranged with a certain distance in the elastic displacement direction of the contact portion, and the circuit is formed. It is of the intermittent type.

Further, in the one described in US Pat. No. 4,031,344, a swing arm made of synthetic resin integrally molded with a hinge for pivoting motion swings in response to a change in webbing winding diameter on a bobbin. When the webbing winding diameter reaches a predetermined amount, the action pin projecting from the swing arm presses the contact terminal formed by press-molding a metal plate to displace the contact portion of the contact terminal. This is a type in which a fixed contact, which is fixed and spaced apart from the contact terminal by a certain distance, is electrically connected to the contact portion of the contact terminal to interrupt the circuit.

[0005]

By the way, it is an important issue to reduce the cost of the seat belt winding amount detection switch by simplifying its structure in order to avoid an increase in the cost of the seat belt device as a whole. There is. In addition, when it is used to control the operation of the lock mechanism equipped in the retractor, it is also important to improve detection accuracy and operation reliability in order to ensure accurate and reliable control of the lock operation. It becomes an issue.

[0006] However, the above-mentioned actual Kai 48-4972
In the safety belt pull-out detection switch device disclosed in Japanese Patent Publication No. 4, the webbing winding amount is detected in cooperation with the swing motion of the contact and the moving motion of the actuator of the micro switch, and the contact forming accuracy is improved. Also, the variation in the mounting accuracy and the variation in the molding accuracy and the mounting accuracy on the micro switch side may increase the variation in the detecting accuracy, resulting in the lowering of the detecting accuracy and the lowering of the operation reliability. There is.

Further, in the above-mentioned US Pat. Nos. 4,163,880 and 4,031,344, both are fixed contacts by elastically displacing a contact portion of a contact terminal formed by press-molding a metal plate into a leaf spring shape. When the contact range of the fixed contact and the contact terminal is wide (the moving stroke of the contact terminal is long), the machining accuracy of these contact terminals greatly affects the switching accuracy. The amount of deformation applied to the contact terminal increases, and a part of the contact terminal plastically deforms, causing a deviation in the electrical contact / disengagement position. It may cause a decrease.
Further, in the device described in U.S. Pat. No. 4,163,880, the contact position of the contact terminal and the pressing position of the lever arm are apart from each other, and a switching error is likely to occur.

Therefore, an object of the present invention is to solve the above problems, and to provide an inexpensive and highly reliable seat belt winding amount detection switch which improves detection accuracy and maintains stable switching accuracy. Is.

[0009]

The above object of the present invention is to urge the winding shaft of a retractor for a seat belt to be pressed against the outermost peripheral surface of a webbing and to be wound on the winding shaft. A mover that follows a change in the webbing winding diameter and moves along a predetermined path, a sliding contact fixed to the mover, and a moving path of the mover accompanying the change in the webbing winding diameter. And a fixed contact for switching the circuit connection mode by contacting or disengaging the sliding contact on the mover when the moving amount of the mover reaches a predetermined amount, and the sliding contact and the fixed contact. This is achieved by a seat belt winding amount detection switch that detects the winding amount of the webbing by the change in the connection form of the circuit due to contact with or disconnection from.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a seat belt winding amount detection switch according to the present invention will be described in detail below with reference to the accompanying drawings. As shown in FIGS. 1 and 2, a seatbelt retractor 2 mounted on a vehicle is usually provided with a retractor base 8 having a U-shaped cross section and both side plates of the retractor base 8. It is rotatably bridged,
A winding shaft 4 fitted with a bobbin 7 around which a webbing 5 is wound, and a winding spring mechanism 6 provided at one end of the winding shaft 4 for urging the winding shaft 4 in the webbing winding direction. And the webbing pull-out direction of the winding shaft 4 (in FIG. 1,
It has an emergency lock mechanism 3 mounted on the other end side of the winding shaft 4 so as to prevent rotation in the X direction).

The seatbelt winding amount detection switch 1 according to the first embodiment of the present invention is used for controlling the electric circuit for warning that the seatbelt is left unfastened, for controlling the operation of the emergency lock mechanism 3, and the like. The winding amount of the webbing 5 wound around the bobbin 7 is detected. As shown in FIG. 3, the seat belt winding amount detection switch 1 is slidable in a cylinder axis direction by a switch housing 9 fixed to a side plate of the retractor base 8 and a cylindrical cylinder portion 10 of the switch housing 9. A mover 12 movably supported, and an inner bottom portion of the cylinder portion 10 and the mover 1.
2, a biasing means 13 for biasing the mover 12 in the direction of pushing the mover 12 outward, a sliding contact 14 fixed to the mover 12, and the cylinder part 10.
It is arranged on the inner wall of the cylinder portion 10 so as to face the moving path of the mover 12 inside, and when the pushing amount of the mover 12 into the cylinder portion 10 reaches a predetermined amount (that is, the mover 12 Fixed contacts 15 and 16 for switching the circuit connection form by contact with the sliding contact 14 when the cylinder moves to the inner bottom side of the cylinder portion 10), and external electric power to these fixed contacts 15 and 16. The circuit connection terminals 17 and 18 for connecting the circuit are provided.

Here, the switch housing 9 is formed by integrally molding the cylinder portion 10 and the connector housing portion 20 for accommodating and holding the circuit connecting terminals 17, 18 with a synthetic resin having an excellent insulating property. A lid 25 made of insulating synthetic resin is attached to the open end of the cylinder portion 10. The lid 25 has a cylinder portion 1 formed by, for example, engaging a locking projection provided on the lid 25 with a locking hole locked on the cylinder portion 10 side.
It is fixed to 0, restricts the upward movement of the mover 12, and at the same time blocks an extra gap at the open end of the cylinder portion 10 to prevent foreign matter from entering the cylinder portion 10.

The circuit connection terminals 17 and 18 are terminals for connecting the connection terminals of an external electric circuit to a connector, and are press-molded integrally with the fixed contacts 15 and 16, respectively, and the switch housing 9 is injection-molded. It is sometimes insert-molded at a predetermined position in the connector housing part 20. That is, as shown in FIGS. 3 and 4, by fitting the connector housing 27 accommodating and holding the connection terminals of the external electric circuit into the connector housing portion 20, the fixed contacts 15 and 16 are connected to the external electric circuit. Electrically connected to.

The mover 12 has a piston-like base end portion 30 slidably supported by the cylinder portion 10, and an abutting member extending from the base end portion 30 and having a tip protruding outside the cylinder portion 10. It has a structure including a shaft portion 28. The tip surface 29 of the contact shaft portion 28 is wound around the bobbin 7 at all times by the urging force of the urging means 13 or in a range where the winding amount is smaller than the switch switching position by a small amount. 5 is pressed against the outermost peripheral surface of the bobbin 5, and the mover 12 can be moved back and forth on the cylinder axis of the cylinder portion 10 in accordance with the change in the winding diameter of the webbing 5 on the bobbin 7. The switch housing 9 is positioned and fixed to the retractor base 8. The switch housing 9 is positioned and fixed to the retractor base 8 by, for example, as shown in FIG. 1, locking projections 22, 23, 24 projecting from the outer surface of the cylinder portion 10 are attached to the retractor base 8. This is achieved by engaging a plurality of formed locking holes.

Further, as shown in FIG. 2, the tip surface 29 of the mover 12 is finished into a smooth arc surface so that the mover 12 is not caught by the webbing 5 when the webbing 5 is pulled out or wound up. In addition, the tip surface 29
The corners 32 and 33 on both sides of the are chamfered to have predetermined R surfaces as shown in FIG. In the first embodiment, the biasing means 13
Is a compression coil spring, the upper end of which is fitted into a boss portion 35 protruding from the lower surface of the base end portion 30 of the mover 12, and the lower end of which is protruded from the inner bottom portion of the cylinder portion 10. It is positioned by being fitted to the portion 36.

That is, in the seatbelt winding amount detection switch 1 described above, a change in the winding diameter of the webbing 5 wound around the bobbin 7 of the seatbelt retractor 2 is directly transmitted to the mover 12 to be moved. Appearing as a moving operation of the child 12 on a predetermined path, and when the moving amount of the mover 12 reaches a predetermined amount (that is, when the webbing winding amount on the bobbin 7 exceeds a predetermined amount). , Fixed contacts 15, 1 arranged on the inner wall of the cylinder portion 10 facing the moving path of the mover 12.
6 and the sliding contact 14 fixed to the mover 12 electrically connect the fixed contacts 15 and 16 to each other and detect that the winding amount of the webbing 5 has reached a predetermined amount.

Therefore, the contact between the fixed contacts 15 and 16 and the sliding contact 14 is performed only by the moving operation of the mover 12 to which the sliding contact 14 is integrally fixed, without the operation of a plurality of parts. Therefore, it is possible to avoid the variation in the moving amount of the sliding contact 14 due to the accumulation of the variations in the molding accuracy and the mounting accuracy of the plurality of operating parts. It is possible to highly accurately set the position of contact with each other and improve the detection accuracy.

Further, since the movement of the sliding contact 14 is not obtained by elastic deformation of the sliding contact 14 itself or the mover 12 itself to which the sliding contact 14 is integrally fixed, the fixed contact 15 , 16 and the sliding contact 14 have a wide connection range (the moving stroke of the sliding contact 14 is long), the sliding contact 14 and the mover 12 are not subjected to stress causing plastic deformation. .

Therefore, the sliding contact 14 and the mover 12 are
Highly reliable seatbelt winding amount that can prevent the electrical contact / separation positions from being displaced due to plastic deformation of the seat, and can maintain the initial winding amount detection timing for a long period of time. A detection switch can be obtained. Further, by fixing the sliding contact 14 to the mover 12,
Since the configuration is such that the change in the winding diameter of the webbing 5 is directly converted into the movement of the sliding contact 14, it is possible to reduce the number of components and reduce the cost.

The seat belt winding amount detection switch 40 according to the second embodiment of the present invention shown in FIGS. 5 to 7 is a switch housing 41 fixed to the retractor base 8.
A movable element 42 on which a pair of shaft portions 42a on the swing center side are rotatably supported, and the switch housing 4
1 and the movable element 42, and urging means 43 for urging the swinging tip of the movable element 42 in the direction of pushing the movable element 42 to the outside of the switch housing 41, and a slider disposed on the movable element 42. When the moving contact 44 and the mover 42 are arranged so as to face the swinging path (moving path) of the mover 42 and the amount of rotation of the mover 42 (the amount of pushing into the switch housing 41) reaches a predetermined amount. Fixed contacts 45 and 46, which switch the connection form of the circuit by contacting the sliding contacts 44, and circuit connection terminals 47 and 48 for connecting an external electric circuit to the fixed contacts 45 and 46 are provided. It is configured.

Here, the switch housing 41 is
Movable element housing 50 for accommodating the movable element 42
And a connector housing portion 51 for accommodating and holding the circuit connecting terminals 47, 48 are integrally molded with a synthetic resin having an excellent insulating property. The mover accommodating housing 50 has a substantially box shape with one surface open, and a lid 53 formed by pressing a metal plate into a substantially U shape is attached to the opening. The lid 53 is provided with a locking hole 53a formed in upper and lower side plate portions of the lid 53 by engaging with locking projections 50a provided on upper and lower side wall portions of the movable element housing 50. It is fixed at 50.

As shown in FIG. 6, a bearing portion 53b for holding one shaft portion 42a of the mover 42 is formed on the lid 53 so as to be raised. That is, the mover 42 is rotatably supported by a bearing portion (not shown) in which the pair of shaft portions 42a, 42a are formed in the mover housing 50 and a bearing portion 53b of the lid 53, and is biased. The swing tip of the mover 42 is urged by the means 43 in a direction in which the mover 42 is pushed out above the mover housing 50 (counterclockwise direction indicated by arrow Y in FIG. 7).

The circuit connection terminals 47 and 48 are terminals for connecting the connection terminals of an external electric circuit to a connector, and are press-molded integrally with the fixed contacts 45 and 46, respectively, and the switch housing 41 is injection-molded. It is sometimes insert-molded at a predetermined position in the connector housing part 51. That is, by fitting a connector housing (not shown) accommodating and holding a connection terminal of an external electric circuit into the connector housing portion 51, the fixed contact 45,
46 is electrically connected to an external electric circuit.

The mover 42 is provided with a contact support arm 42b extending radially outward from the center of swing and a tip end of the contact support arm 42b extending along the rotation direction so that the mover is movable. The contact portion 42c protruding to the outside of the child housing 50 is integrally formed of synthetic resin, and the sliding contact 44 is attached to the recess 42e formed in the contact support arm 42b.

Then, as shown in FIG. 7, the contact portion 42c
Of the webbing 5 wound around the bobbin 7 is pressed against the outer peripheral surface of the webbing 7 at all times by the urging force of the urging means 43 or in a range where the winding amount is smaller than the switch switching position and the webbing is fully wound. The switch housing 41 is urged so that the mover 42 swings around the shaft portions 42a, 42a in accordance with the change in the winding diameter of the webbing 5 on the bobbin 7. It is positioned and fixed at 8. The biasing means 43 is a torsion coil spring in the second embodiment.

In the switch housing 41, the hook portion 55 and the engaging hole 56 (see FIG. 5) formed on the outer surface of the housing 41 are engaged with the engaging portion formed on the retractor base 8. Positioned and fixed to the retractor base 8 by. Further, as shown in FIGS. 5 and 7, the tip 42d of the mover 42 is finished into a smooth arc surface so that the mover 42 is not caught by the webbing 5 when the webbing 5 is pulled out or wound. ing.

That is, also in the seat belt winding amount detection switch 40 described above, the change in the winding diameter of the webbing 5 wound around the bobbin 7 of the seat belt retractor is movable, as in the case of the first embodiment. When the movable element 42 is directly transmitted to the movable element 42 and appears as a rotating operation (moving operation) of the movable element 42 on a predetermined path, and when the amount of rotation of the movable element 42 reaches a predetermined amount (that is, the bobbin 7). When the upper webbing winding amount is equal to or more than a predetermined amount, the movable element 42 is movable with the fixed contacts 45 and 46 arranged on the inner wall of the movable element housing 50 facing the swing path (moving path) of the movable element 42. When the sliding contact 44 fixed to the child 42 contacts, the fixed contacts 45 and 46 are electrically connected to each other, and it is detected that the winding amount of the webbing 5 has reached a predetermined amount.

Therefore, the fixed contacts 45 and 46 and the sliding contact 44 are brought into contact with each other only by the rotating operation of the mover 42 to which the sliding contact 44 is integrally fixed, without the operation of a plurality of parts. Since it is performed, it is possible to avoid variations in the movement amount of the sliding contact 44 due to the accumulation of variations in the molding accuracy and mounting accuracy of a plurality of operating parts. It is possible to set the position where and come into contact with high accuracy, and improve the detection accuracy.

Further, since the swing of the sliding contact 44 is not obtained by elastic deformation of the sliding contact 44 itself or the mover 42 itself to which the sliding contact 44 is integrally fixed, the fixed contact. Even when the connection range between the sliding contacts 45 and 46 and the sliding contact 44 is wide (the moving stroke of the sliding contact 44 is long), the sliding contact 44 and the mover 42 are not stressed to cause plastic deformation. Absent.

Therefore, these sliding contacts 44 and the mover 4 are
A seat belt winding with high operation reliability that can prevent the electrical contact / separation position from being displaced due to the plastic deformation of No. 2 and can maintain the initial winding amount detection timing for a long period of time. A quantity detection switch can be obtained. Further, since the sliding contact 44 is fixed to the mover 42 and the change in the winding diameter of the webbing 5 is directly converted into the movement of the sliding contact 44, the number of constituent parts can be reduced and the cost can be reduced. Can be achieved.

The seat belt winding amount detection switch of the present invention is not limited to the configuration of each of the above embodiments,
It goes without saying that it can take various forms. For example,
In each of the above-described embodiments, when the webbing winding amount is larger than the predetermined amount, the fixed contact arranged facing the moving path of the mover and the sliding contact on the mover come into contact with each other, so that the circuit Although the connection form is switched, the circuit connection form may be switched by contact between the fixed contact and the sliding contact on the mover when the moving amount of the mover is smaller than a predetermined amount. it can.

Further, the switching of the connection form of the circuit, which is performed by the contact or the separation of the fixed contact and the sliding contact on the mover,
The circuit may be turned on / off by opening / closing the two contacts, or the connection relationship between the plurality of three or more contacts may be switched in a plurality of steps. For example, when the warning light that warns that the seat belt is not tightened is turned on when the webbing winding diameter is larger than a predetermined amount, the circuit is turned on by opening and closing the two contacts as in the above-described embodiments.・ It can be configured to switch off, and in the case of energizing the tension reducer that controls the tightening force of the seat belt in addition to lighting the warning light, turning on / off the three contacts will output two systems. Should be obtained.

[0033]

According to the seat belt winding amount detecting switch of the present invention, the fixed contact point and the sliding contact point which are necessary to detect that the winding amount of the webbing reaches a predetermined amount by switching the circuit connection form. The contact with or disengagement from the moving parts is performed only by the moving operation of the mover with the sliding contacts integrally fixed, without the operation of the multiple parts. Since it is possible to avoid variations in the moving amount of the sliding contact due to accumulation, it is possible to set the position at which the fixed contact and the sliding contact come into contact with or separate from each other with high accuracy, and improve the detection accuracy. it can.

Further, since the movement of the sliding contact is not obtained by elastic deformation of the sliding contact itself or the mover itself to which the sliding contact is integrally fixed, the movement stroke of the sliding contact is Even if it is long, no stress that causes plastic deformation is applied to the sliding contacts and the mover. Therefore, it is possible to prevent the electrical contact / separation position from being displaced due to the plastic deformation of these sliding contacts and the mover, and to maintain the initial winding amount detection timing for a long period of time. It is possible to obtain a seat belt winding amount detection switch having high operation reliability.

Further, since the sliding contact is fixed to the mover and the change in the winding diameter of the webbing is directly converted into the movement of the sliding contact, the number of constituent parts can be reduced and the cost can be reduced. be able to. Therefore, it is possible to provide a seat belt winding amount detection switch that improves detection accuracy and maintains stable switching accuracy, and that is inexpensive and highly reliable in operation.

[Brief description of drawings]

FIG. 1 is a side view of a seat belt retractor including a seat belt winding amount detection switch according to a first embodiment of the present invention.

FIG. 2 is a front view of the seat belt retractor shown in FIG.

3 is a partially cutaway front view of the seat belt winding amount detection switch shown in FIG.

FIG. 4 is a side view of the seat belt winding amount detection switch shown in FIG.

FIG. 5 is an exploded perspective view of a seat belt winding amount detection switch according to a second embodiment of the present invention.

6 is a cross-sectional view of a main part of the seat belt winding amount detection switch shown in FIG. 5 in a retractor-attached state.

FIG. 7 is a front view of the seat belt winding amount detection switch shown in FIG. 6 in a state where the retractor is attached.

[Explanation of symbols]

 1 seat belt winding amount detection switch 2 seat belt retractor 4 winding shaft 7 bobbin 5 webbing 9 switch housing 10 cylinder portion 12 mover 13 biasing means 14 sliding contact 15 fixed contact 16 fixed contact 20 connector housing 28 Axial portion 29 Tip surface 30 Base end portion

Claims (1)

[Claims] 1. A predetermined amount is urged to press the outermost peripheral surface of a webbing wound around a take-up shaft of a seat belt retractor so as to follow a change in a webbing winding diameter on the take-up shaft. A mover that moves along the path, a sliding contact fixed to the mover, and a moving path of the mover along with a change in the webbing winding diameter are arranged so that the mover moves a predetermined amount. A fixed contact for switching the circuit connection form by contacting or disengaging the sliding contact on the mover when the contact point reaches Seat belt winding amount detection switch that detects the amount of webbing winding based on changes.