JP2711428B2 - Seat belt winding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt retractor, and more particularly, to a seat belt retractor in which the belt withdrawal force is substantially constant even when the degree of withdrawal of the seat belt is different.

[0002]

2. Description of the Related Art Conventionally, in the case of a seat belt winding device for winding a seat belt mounted on an automobile or the like by a spring drive method, the spring tension increases as the amount of pulling out of a safety belt such as a seat belt increases. There was a problem of doing. For example, the retracting force of the seat belt having a tension of 2 (N) at the start is 18 when the belt is completely pulled out.
In some cases, it has increased to (N). Another cause of such an increase in the winding force is that the diameter of the belt webbing winding on the winding shaft becomes smaller as the amount of withdrawal of the belt increases, and more and more force is transmitted to the belt.

In order to eliminate this drawback, two rope pulleys are arranged between the belt take-up shaft and a spiral spring biased by the rotation of the shaft so as to be parallel to each other and at a lateral position. A seat belt winding device having a transmission device connected thereto has been devised (US Pat. No. 3,997,971).
No. 26). The rope pulleys of this device are conically tapered in opposite directions and are connected to each other by a rope wound on the surface of the rope pulley so as to prevent relative rotation. At this time, a spiral guide groove is formed on the outer peripheral surface of the rope pulley connected to the spiral spring, and the outer peripheral surface of the other rope pulley connected to the belt winding shaft has a smooth surface.

[0004] A guide groove formed in the rope pulley allows the rope pulley connected to the spiral spring to extend from the rope pulley at a given rotation position and a predetermined diameter of the rope pulley, and a groove on the opposite side from that position. It is ensured that it is extended to the other rope pulley without any.

[0005]

In the winding device having such a structure, the rope may slide on the rope pulley having a smooth surface in the axial direction of the rope pulley. For this reason, there is a danger that the gear ratio changes and that the rope comes off the guide groove of the rope pulley having the spiral spring. By the way, in the structure of the transmission having such a configuration, by appropriately setting the inclination angle of the guide groove of the rope pulley connected to the spiral spring and the cone angle of the cone shape of the rope pulley, the pull-out force of the seat belt at all pull-out degrees is adjusted. Can be made substantially constant.
Therefore, an object of the present invention is to provide a seat belt for a seat belt in which the gear ratio can take a predetermined constant value as much as possible in all degrees of withdrawal of the seat belt, and can remove the risk of detachment and / or slippage of the rope from the guide groove. It is to provide a winding device.

[0006]

In order to solve this problem, according to the present invention , a spiral guide groove is formed on the outer peripheral surface.
Coaxial with the axis of rotation of the frustum-shaped first rope pulley
And the first rope is connected so as not to rotate relative to each other.
A predetermined fixing point on the outer peripheral surface of the pulley is wound around the guide groove.
One end of the string-shaped body arranged to be attached is fixed,
The cord is rotated with respect to the first rope pulley.
The axes are parallel and laterally spaced and have a frusto-conical shape.
Spiral guide carved on the outer surface of rope pulley 2
Over the groove, coaxial with the rotation axis of the second rope pulley
The second rope pulley is urged in a winding direction of the string-like body and the seat belt by a spring device connected so as not to rotate relative to each other, and at least one of the first rope pulley and the second rope pulley is respectively of the seat belt retractor which is adapted to the diameter change in opposite directions along the axial direction of the rotary shaft, with the said spring device is accommodated in a hollow space formed in the second rope pulley, the second Guide groove on outer surface of rope pulley 1
Is at a predetermined angle to the side of the first rope pulley.
A spiral formed to form a gap,
The guide groove on the outer peripheral surface of the rope pulley is provided with the first rope pulley.
The string that is hung over the rope is on the side of the second rope pulley
Spiral engraved at a specified angle and spacing
It is characterized in that it has been said.

It is preferable that the hollow chamber is open toward the front side of the second rope pulley, and the spring device is housed therein. Further, it is preferable that the hollow chamber has a predetermined diameter dimension on a side surface of the second rope pulley and is provided in advance. In addition, it is preferable that the hollow chamber is arranged coaxially with the second rope pulley. In addition, the second
It is preferable that the rope pulley is rotatably mounted on a rotating shaft in a housing, and the hollow device formed therein accommodates the spring device composed of a spiral spring. It is preferable that one end of the spring device has a diameter larger than a diameter of a rotation shaft supporting the second rope pulley, and is fixed to a pin holding the rotation shaft. Wherein preferably forms a truncated cone shape of opposite direction to the first rope pulley and a second rope pulley. Frusto- conical shape of the first rope pulley and the second rope pulley
It is preferable that the generating lines on the outer peripheral surface are set to have opposite curvatures and extend with each other. The generatrix of the first rope pulley and the second rope pulley on the truncated cone-shaped outer peripheral surface is set to an opposite curvature , and when the cord- shaped body undergoes a tensile elongation operation, the pullout force of the seat belt is slightly reduced. As it is held large and the amount of withdrawal increases,
Preferably, the pull-out force is set so as to decrease. It is preferable that an average diameter of the first rope pulley supporting the belt reel is smaller than an average diameter of the second rope pulley to which a spiral spring is connected. Preferably, the diameter of the large diameter portion of the first rope pulley is equal to the diameter of the small diameter portion of the second rope pulley. The distance in the axial direction of the second outer peripheral surface which is formed on the guide groove of the rope pulley are equally formed, and the first has large intervals than intervals equal in the axial direction of the guide groove formed on the outer peripheral surface of the rope pulley It is preferable to form it.

[0008]

According to this construction, it is ensured that the rope as a string is guided perfectly in the spiral guide groove on both rope pulleys. In some cases, a string or other flexible tensioning element located in the guide channel may be used. The detachment of the rope from the guide groove not only depends on the arrangement of the guide groove but also that the inclination of the guide groove is always the same at the tangential point, and that the extension line of the guide groove is linear with each other at both insertion points of both rope pulleys. Achieved by doing so. In other words, the winding in the axial direction of both the guide grooves
And spacing are different respectively, without rope is always bent, are inserted into both the guide grooves which are connected to each other by a rope. In one rope pulley, the windings of the guide grooves are provided as closely as possible.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a seat belt retractor according to the present invention. In FIG.
The seat belt winding device according to the present invention is a belt reel 1.
1, a seat belt 17 of which a part is shown in FIG.
The belt reel 11 is rotated by a rotation shaft 19 to a housing 28.
Is rotatably supported inside. Further, the end opposite to the belt reel 11 of the rotary shaft 19 in the housing 28 first rope pulley 12 is fixed which is formed in a conical trapezoidal shape. A spiral guide groove 15 is formed in the outer peripheral surface of the first rope pulley 12. The extended shape of the guide groove is clearly shown in FIG.

On the other hand, the second rope pulley 14 is rotatably supported by a rotating shaft 20 fixed to a part of the housing 28. The rotating shaft 20 is parallel to the rotating shaft 19 and is spaced apart from the housing 28 by a predetermined distance.
It is fixed to the inner surface. As shown in FIG. 1, a cylindrical hollow chamber 21 coaxial with the rotation shaft 20 is formed in the second rope pulley 14. The spiral spring device 16 is mounted in the hollow chamber 21. One end of the spiral spring device 16 is fixed to a pin 22 fixed to a housing that supports the rotating shaft 20, and the other end is a hollow chamber 21 of the second rope pulley 14.
Is fixed at a part of the inner peripheral position.

4 is inserted into the guide groove 18 of the second rope pulley 14 by the spiral spring device 16 and FIG.
Is transmitted to the second rope pulley 14 in order to wind the rope 13 as a string fixed at the fixing point 23 shown in FIG. As shown in FIGS. 1 and 4, the rope 13 extends from the minimum diameter of the rope pulley 14 to the first position.
To a part of the guide groove 15 of the rope pulley 12.
In the first rope pulley 12, the rope 13 is fixed on the outer peripheral surface of the first rope pulley 12 at a fixing point 24.

In the winding state shown in FIGS. 1 and 4, the rope 13 is almost completely wound on the second rope pulley 14 and almost completely unwound from the first rope pulley 12. In this state, the belt winding 25 on the first belt reel 11 is the thickest. That is, the longest belt length is wound on the first belt reel 11, and the seat belt 17 has the shortest length in that state. The seat belt 17 has a winding force K indicated by an arrow in FIG.
The first rope pulley 12 rotates in a predetermined rotation direction, and the rope 13 is gradually wound on the first rope pulley 12. In this case, the first rope pulley 12 is inserted into the guide groove 15 while the rope 13 is inserted into the guide groove 15.
Wound on top. At the same time, the rope 13 is gradually rewound from the second rope pulley 14.

According to the present invention, the rope 13 is
Angle of the two guide grooves 15, 18 at the point where they are inserted into the groove, that is, a linear extension line along the two guide grooves 15, 18 at the point where the linear rope portion 13 'is inserted into the groove, and rotation. The angles between the planes 26, which are perpendicular to the axes 19, 20, respectively, are set equal. Further, at the anchoring points 23 and 24, the ends of the rope 13 are fixed by appropriate means, and the rope portion 13 is stretched straight without being restrained between the first rope pulley 12 and the second rope pulley 14. ′ Is not bent and both guide grooves 15,
When the distance A between the axes of the guide grooves 15 of the first rope pulley 12 is constant, the distance B between the axes of the guide grooves 18 of the second rope pulley 14 having a large diameter is As is clear from FIG. 4, the diameter increases in the axial direction toward the large-diameter portion.

The fact that the winding of the spiral guide groove 15 of the first rope pulley 12 is shifted by the same axial distance A means that the inclination angle of the guide surface increases from α to β from the large diameter portion to the small diameter portion. Means to do. It is also conceivable to guide the guide groove 15 along the outer peripheral surface of the first rope pulley 12 so that the inclination angle α is constant. However, this means that the distance A between the axes of adjacent turns of the guide groove 15 decreases as the pulley diameter decreases.
Correspondingly, the interval B between the axes of adjacent turns of the guide groove 18 of the second rope pulley 14 can be reduced, and the inclination angle can be kept constant. FIG. 2 shows both the first rope pulley 12 and the second rope pulley 1 having opposite conical shapes.
4 is schematically shown. At this time, the guide grooves 15, 18 are not shown.

FIG. 3 shows a state in which both ends of the rope 13 completely wound or completely unwound by the first rope pulley 12 or the second rope pulley 14 in the two embodiments. FIG. 3 shows, in one embodiment, that the ropes 13 indicated by solid lines cross and are guided from the tangential direction to the adjacent first rope pulley 12 and second rope pulley 14. On the other hand, the fully wound state or the completely unwound state of the rope 13 guided so as to rotate in the same direction without crossing from the first rope pulley 12 to the second rope pulley 14 is indicated by a chain line. It is shown. As described above, in the present invention, a winding device (crossover or rotation in the same direction) by any of the rope passing methods is possible.

In this embodiment, the first rope pulley 1
For example, the diameter of the small diameter portion 2 is, for example, 15 mm or slightly larger, and the diameter of the large diameter portion is set to 30 to 35 mm. Correspondingly, the diameter of the small diameter portion of the second rope pulley 14 is 30 to 35 mm and the diameter of the large diameter portion is 10 mm.
It is set to 0 to 120 mm.

FIG. 5 is a modification showing a modification of the embodiment shown in FIG. In the figure, a belt reel 1 is provided at one end.
The bus bar 29 of the surface forming the outer peripheral surface of the first rope pulley 12 to which the first rope pulley 12 is fixed and housed in the housing 26 has a convex shape, and the guide groove 15 is formed along the surface of the outer peripheral surface of the first rope pulley 12. ing. At the maximum diameter position of the first rope pulley 12, the tangent of the bus 29 is set to be substantially horizontal, and the curvature changes toward the rotation axis 19. The shape of the generatrix is preferably a semicircular shape. The peripheral surface defined by the generatrix 30 of the second rope pulley 14 provided adjacent to the first rope pulley 12 is constituted by a concave surface complementary to the convex peripheral surface of the first rope pulley 12. I have. The size of the pulley is set such that the maximum diameter of the first rope pulley 12 fitted on the rotating shaft 19 is equal to the minimum diameter of the second rope pulley 14. A guide groove 18 is formed on the peripheral surface of the second rope pulley 14. In the winding state, the rope 13 is almost wound around the second rope pulley 14 and unwound from the first rope pulley 12, as shown in FIG. In this state, the seat belt 17 is most wound up. That is,
In the belt holding state, the belt winding 25 on the belt reel 11 is the thickest in this state. Here, FIG.
As shown in (1), when the seat belt 17 is pulled out by the winding force K, the first rope pulley 12 rotates, and the rope 13 is wound around the first rope pulley 12. In the device shown in FIG. 5, the same relationship between the guide grooves 15 and 18 as in the schematic diagram shown in FIG. 4 is established.

FIG. 6 shows a bus bar 29 ', 3' of the first rope pulley 12 and the second rope pulley 14 as another modification.
As shown in the outline by a dashed line, the peripheral surfaces 31 and 32 of 0 ′ constitute a concave surface from a small diameter portion, and are curved at an intermediate portion to form a convex surface. The peripheral surface shape of both pulleys 12 and 14 is set so that the convex surface and the concave surface of the opposing peripheral surfaces 31 and 32 complement each other.

FIGS. 7 to 9 are characteristic curves showing the relationship between the pull-out force K and the seat belt pull-out amount L. FIG. FIG.
Are characteristic curves in the case of the seatbelt winding device according to the embodiment shown in FIGS.
In this case, the draw-out force K as a function of the draw-out amount due to the increase of the spring action shows a straight line (straight line 36) having a predetermined constant gradient in the conventional type. In the device provided with the rope pulleys 12 and 14 according to the present invention, the characteristic curve 33 does not depend on the increase of the amount of drawing L.
This indicates that the pull-out force K is constant. At this time, the area indicated by reference numeral 27 is a non-effective boundary area, and the effective area is indicated by reference numeral 28. FIG. 8 is a characteristic curve diagram showing the relationship between the pull-out force K and the pull-out amount L of the seat belt retractor according to the modification shown in FIG. The characteristic curve 34 according to the device of the present invention is shown as a predetermined function. As shown in FIG. 5, when the seat belt 17 is wound most, the rope 13 is located at the maximum diameter of the first rope pulley 12 and at the minimum diameter of the second rope pulley 14, as shown in FIG. The pull-out force K in this state is maximum. When the seatbelt 17 is pulled out, the linear rope portion 13 'is quickly put on the small-diameter portion of the first rope pulley 12 and the large-diameter portion of the second rope pulley 14, and the ineffective area is formed. Then, the pull-out force decreases and becomes almost constant in the effective area. FIG. 9 is a characteristic curve diagram of the seat belt retractor shown in FIG. According to the apparatus shown in FIG. 6, as shown in FIG. 9, the drawing force K-drawing amount L function is represented by a curve 35. According to the same curve, at the beginning of the drawing, the drawing force is maintained at about 7N, and when the drawing amount L increases from the non-effective area to the effective area, it decreases to about 4N.

[0020]

As is apparent from the above description , the outer peripheral surface of the rope pulley is projected regardless of the amount of pull-out of the seat belt.
Since it is used as effectively as possible, the pull-out force can be maintained at a predetermined value, and stable pull-out of the seat belt can be realized. Also, pull out any seat belt
The gear ratio is determined in advance
A certain value can be obtained, and the rope can be removed from the guide groove and
Can eliminate the danger of slippage. Furthermore, a spring dress
The device is housed in the hollow room inside the rope pulley.
Length in the direction of the axis is shorter, and overall compact
This provides an effect that a simple seat belt winding device can be provided .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view partially showing a seat belt winding device according to the present invention.

FIG. 2 is a schematic perspective view schematically showing a state in which the rope pulleys shown in FIG. 1 are interconnected by ropes.

FIG. 3 is a partial front view of both rope pulleys in directions indicated by arrows III in FIGS. 2 and 4 for showing both final stages of rope pulley rotation.

FIG. 4 is a partially enlarged view showing only a rope pulley on which a rope is wound in order to show different axial intervals of guide grooves in the rope pulley.

FIG. 5 is a partial sectional view showing a modification of the seat belt retractor shown in FIG. 1;

FIG. 6 is a partial cross-sectional view showing another modification of the seat belt retractor.

7 is a characteristic curve diagram showing a relationship between a pull-out force K and a seat belt pull-out amount L in the seat belt retractor shown in FIG.

8 is a characteristic curve diagram showing a relationship between a pull-out force K and a seat belt pull-out amount L in the seat belt retractor shown in FIG.

9 is a characteristic curve diagram showing a relationship between a pull-out force K and a seat belt pull-out amount L in the seat belt retractor shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Belt reel 12 1st rope pulley 13 Rope 14 2nd rope pulley 15, 18 Guide groove 16 Spiral spring device 21 Hollow room 23, 24 Fixing point 26, 28 Housing 29, 30 Bus surface

Claims (12)

(57) [Claims] 1. A belt reel on which a seat belt is wound has a truncated conical shape in which a spiral guide groove is formed on an outer peripheral surface.
Coaxial and relative to the rotation axis of the first rope pulley of
Connected so as not to rotate, outside the first rope pulley
A predetermined fixing point on the peripheral surface is wound around the guide groove.
One end of the string-like body arranged as described above is fixed, and the string-like body is
Whether the rotation axis is parallel to the first rope pulley
Frustum-shaped second ropes spaced apart on one side
Hooks over spiral guide grooves engraved on the outer surface of the pulley
And coaxial with and relative to the rotation axis of the second rope pulley.
The second rope pulley is urged in a winding direction of the string- like body and the seat belt by a spring device connected so as not to rotate, and at least one of the first rope pulley and the second rope pulley has a respective rotation shaft. In the winding device for a seat belt, the diameter of the spring device is changed in the opposite direction along the axial direction, the spring device is housed in a hollow chamber formed in the second rope pulley, and the first rope pulley is accommodated in the hollow device.
The guide groove on the outer peripheral surface of the
A spiral that is engraved with a predetermined angle and spacing
The guide groove on the outer peripheral surface of the second rope pulley is
The string-like body wound around the first rope pulley is the second rope pulley.
Form a predetermined angle and spacing with respect to the side of the pulley
A winding device for a seat belt, wherein the winding device is formed into a spiral shape . 2. The winding device for a seat belt according to claim 1, wherein the hollow chamber is opened toward a front side of the second rope pulley, and the spring device is accommodated in the hollow chamber. 3. The winding device for a seat belt according to claim 1, wherein the hollow chamber has a predetermined diameter on a side surface of the second rope pulley and is provided in advance. 4. The winding device for a seat belt according to claim 1, wherein the hollow chamber is disposed coaxially with the second rope pulley. 5. The second rope pulley is rotatably mounted on a rotating shaft in a housing, and the hollow device formed therein accommodates the spring device formed of a spiral spring. The winding device for a seat belt according to any one of claims 1 to 4. 6. The spring device according to claim 5, wherein one end of the spring device has a diameter larger than a diameter of a rotation shaft supporting the second rope pulley, and is fixed to a pin holding the rotation shaft. 3. The winding device for a seat belt according to claim 1. Wherein said first rope pulley and the seat belt winding according to any one of claims 1 to 6 and the second rope pulley, characterized in that a conical trapezoidal shape opposite Taking device. 8. The curvature of the first rope pulley and the second rope pulley on the outer peripheral surface of the truncated cone shape are opposite to each other.
The winding device for a seat belt according to any one of claims 1 to 6, wherein the winding devices are set to be extended to each other. 9. A case where the generatrix of the outer peripheral surface of the first rope pulley and the second rope pulley on the truncated cone shape is set in the opposite direction, and a tensile elongation operation of the cord- like body occurs. 9. The seat belt retractor according to claim 8, wherein the pull-out force of the seat belt is slightly increased, and the pull-out force decreases as the pull-out amount increases. 10. The apparatus according to claim 1, wherein an average diameter of the first rope pulley supporting the belt reel is smaller than an average diameter of the second rope pulley to which a spiral spring is connected. The winding device for a seat belt according to claim 1. 11. The seat according to claim 1, wherein the diameter of the large-diameter portion of the first rope pulley is equal to the diameter of the small-diameter portion of the second rope pulley. Belt winding device. 12. A guide groove formed on an outer peripheral surface of the second rope pulley has an equal interval in an axial direction , and a guide groove formed on an outer peripheral surface of the first rope pulley.
Seatbelt retractor according to any one of claims 1 to 11, characterized in that formed in the intervals not greater than the equal spacing in the axial direction.