JPH085360B2 - Ratchet type retrograde device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a winding and storing device for a vehicle seat belt,
Alternatively, the present invention relates to a retrograde prevention device that can be applied to a winding device involving a rotational movement such as a preloader device that automatically winds looseness of a seat belt in the event of a collision accident or a relative movement device involving a linear movement.

<Conventional technology> For example, seats of automobiles are provided with seat belts for restraining occupants from moving forward in order to prevent the occupants from being thrown forward in a collision or the like. The retractor device with an automatic locking device for emergency (hereinafter referred to as ELR) that locks the seat belt winding shaft only at the time of sudden stop or collision without restricting the operation during operation
May be provided.

This ELR device is generally of a type that locks the winding shaft within an extremely short time by detecting deceleration at the time of collision and sudden unwinding of the seat belt, so that it is especially effective in the initial state. If the amount of slack in the seat belt is large, the restraining force of the occupant may be insufficient.

Based on this point of view, for example, Japanese Patent Publication No. 53-21574 or Japanese Utility Model Publication No. 53-25943 discloses a preloader device for tensioning a seat belt by rapidly winding the end portion of the seat belt at the time of a collision. There is. In these ELR devices or preloader devices, a reverse rotation preventing device including a ratchet wheel and a ratchet pole is usually used as a mechanism for freely winding and unwinding a seat belt and locking only in an emergency.

By the way, when locking the take-up shaft of a belt-like object having a certain width such as a vehicle seat belt, in order to receive a relatively large torque and prevent the take-up shaft from twisting, It is considered preferable to provide ratchet mechanisms at both ends of the shaft in terms of strength or improvement of reliability. In addition, such a ratchet mechanism is not limited to one involving a rotary motion, but is also applicable to a winding or retracting device involving a linear motion.

<Problems to be solved by the invention> However, due to a manufacturing error of the ratchet wheel or an assembly error with respect to the winding shaft, the ratchet wheel on both sides and the ratchet pole are not uniformly engaged, and only one ratchet is provided. May be engaged and the other ratchet may be in an unengaged state. In that case, the load concentrates only on one ratchet mechanism, and the meaning of providing two sets of ratchet mechanisms is lost.

In view of such problems of the conventional technology, a main object of the present invention is to provide a retrograde prevention device that can always reliably support a load with ratchet mechanisms on both sides.

<Means for Solving the Problems> According to the present invention, such an object is to provide a pair of ratchet tooth rows fixed to the first common member in parallel with each other,
A pair of ratchet pawls provided on a second common member for engaging the ratchet teeth of each ratchet tooth row, and limiting relative movement between the two members in one direction along the tooth row direction. In the ratchet type retrograde prevention device for performing one of the pair of ratchet poles, the tooth row direction position at which one of the pair of ratchet poles can rush into the ratchet interdental space of the corresponding tooth row is the other ratchet pole. Has a phase lag with respect to the position in the tooth row direction in which it can be inserted into the inter-ratchet tooth space of the tooth row, and one of the ratchet poles engages with the ratchet tooth of the corresponding tooth row. The ratchet type anti-backlash prevention device is characterized in that the required plunge amount is smaller than the plunge amount required for the other ratchet pole to engage with the ratchet teeth of the corresponding tooth row. It is achieved by.

<Operation> In this way, the other ratchet pole on the phase lead side is
Engagement is always possible prior to the one on the phase delay side. However, since the amount of plunge required for engagement is greater in the one ratchet pole than in the other ratchet pole, if one ratchet pole achieves engagement with the ratchet wheel, the other ratchet pole remains unchanged. It engages the corresponding ratchet wheel, but if one ratchet pole cannot engage the ratchet wheel, the other does not.
That is, unless the engagement of one ratchet pole on the lagging side with the corresponding ratchet wheel is achieved, the other ratchet pole on the leading side cannot engage with the corresponding ratchet wheel. Therefore, it is possible to avoid the disadvantage that only one of the ratchet poles engages with the corresponding ratchet tooth.

Embodiment Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a structure around a seat belt to which the present invention is applied. A seat belt 3 pulled out upward from a webbing retractor 2 fixedly installed in a lower portion of a center pillar 1 in a vehicle compartment is a center pillar. After passing through the through ring 4 attached above 1, the sheet 6 is extended downward, and the end portion 6 is attached to the rear side surface of the seat 5. A tongue plate 7 is provided between the through ring 4 and the end portion 6 of the seat belt 3 so as to be movable along the seat belt 3.

After the occupant seated on the seat 5 pulls out the seat belt 3 from the webbing retractor 2, the tongue plate 7
Is connected to the buckle 8 attached to the side surface of the seat opposite to the fixing point of the seat belt end portion 6, so that the seat belt 3 is stretched around the shoulder, chest and waist of the occupant.

As shown in FIG. 2, the webbing retractor 2 is an EL device that retracts and unwinds the seat belt 3 during normal use.
An R device 9, a traction device 10 for tensioning the looseness of the seat belt 3 at the time of a collision, a drive device 11 that applies a rotational force to the traction device 10, and a deceleration sensor 12 that detects a collision.

The ELR device 9 applies a rewinding rotational force to the webbing drum 13 that winds the seat belt 3 by a built-in spring means, and at the same time, at the time of sudden deceleration, the seat belt 3 can be prevented from being fed out by a ratchet mechanism. .

The drive device 11 applies a thrust force to the piston body by the explosive force of explosives and the like, and applies a rotational force to the traction device 10 via a wire connected to the piston body, and is a deceleration sensor including a weight and a firing pin. By the action of 12, ignition and explosion can be done.

As best shown in FIG. 3, the housing 14 of the traction device 10
Is formed by bending a metal plate, and a pair of ratchet wheels 15a, 15b are rotatably supported on the inner surface of the metal plate by a penetrating shaft 16 as a first common member. The ratchet wheels 15a and 15b and the penetrating shaft 16 are integrally connected, and a pulley 17 is fixed to one end of the penetrating shaft 16 protruding to the outside of the housing 14. One end of the pulley 17 is connected to the driving device 11, and the other end is connected to the pulley 17.
A wire 18 fixed in place at 17 is suspended, and a rotational force is applied by the driving device 11 described above.

Both ratchet wheels 15 as shown in FIG.
A clamp cam 19 having a substantially semicircular cross section is rotatably provided at a proper position on the outer peripheral side of the inner surfaces of the a and 15b facing each other. A plurality of clamp grooves 20a, 20b having substantially complementary shapes are formed on substantially the entire length of the opposing surfaces of the lower end edge of the clamp cam 19 and the penetrating shaft 16.

Below the housing 14, a ratchet pole member 21 as a second common member made of a substantially strip-shaped plate material is attached to the penetrating shaft 16 so that the ratchet pole member 21 can slidably contact the outer circumferences of the ratchet wheels 15a and 15b. Are extended in parallel. The ratchet pole member 21 has a hole 22 formed in the housing 14 at both ends thereof.
So that the pair of ratchet poles 25a, 25b provided at the upper edges of both ends of the ratchet wheels 15a, 15b can engage with and separate from the lower edge of the ratchet wheel 15a, 15b. Has been Ratchet pole member
A tension coil spring 23 is stretched between both ends of the housing 21 and the housing 14 and constantly urges the upper edge of the ratchet pole member 21 toward the ratchet wheels 15a and 15b (fifth).
Figure).

As shown in FIGS. 6 and 7, first and second ratchet teeth 24a and 24b, both of which have a sawtooth shape, are formed on the outer peripheral portions of the ratchet wheels 15a and 15b, respectively. Both ratchet teeth 24a, 24b have the same outer diameter dimension, pitch dimension, and tooth length dimension.
The bases of the trailing edges 28a, 28b of a, 24b are (2 sets of ratchet teeth 24
a, 24b and ratchet poles 25a, 25b are in the state of being engaged at the same time) and are in phase with each other along the dentition direction and are aligned, but the vertices of these teeth
A phase difference indicated by the P dimension is provided between 29a and 29b. In the case of the present embodiment, this phase difference is provided by making the edge angle of the first ratchet tooth 24a more acute than the edge angle of the second ratchet tooth 24b. That is, the trailing edges 28a, 28b and the leading edge 30 of both ratchet teeth 24a, 24b.
The angle between a and 30b is large on the side of the second ratchet tooth 24b (α1 <α2).

Further, the first ratchet pole 25a as one ratchet pole corresponding to the first ratchet tooth 24a having a relatively small angle (α1) is substantially complementary to the base of the trailing edge 28a of the first ratchet tooth 24a. A second ratchet pole corresponding to the second ratchet tooth 24b having a relatively large angle (α2) while having a shape
The cutting edge of the ratchet pole 25b is cut off at its apex, and then an appropriate chamfered portion or tapered surface 26 is provided.

Here, the first ratchet pole 25a has the apex 31a, the first
Engagement between the ratchet pole and the ratchet tooth is achieved if the first ratchet pole 25a projects even slightly into the inter-ratchet tooth space through the leading edge 30a of the ratchet tooth 24a and when aligned with its apex 29a. In particular, since the trailing edge 28a of the first ratchet tooth 24a is an undercut surface that is dug in so that the cutting edge has an acute angle, a force in the reverse direction is applied to both the ratchet pole and the ratchet tooth. However, both parts will be fully engaged.

However, since the tapered surface 26 is provided at the engaging portion of the second ratchet pole 25b, the apex 31a of the first ratchet pole 25a is the apex 29a of the first ratchet tooth 24a.
Even when aligned with, the apex 31b of the second ratchet pole 25b
Are spaced radially relative to the apex 29b of the second ratchet tooth 24b, as indicated by the Q dimension, and no engagement between the two parts is achieved. Further, even if the second ratchet pole 25b slightly rushes into the interdental space of the second ratchet teeth 24b due to tilting of the ratchet pole member 21, if a force in the reverse direction is applied between the two portions, The apex 29b slides on the tapered surface 26, and eventually a complete engagement is not achieved.

Thus, the engagement between the second ratchet pole 25b and the second ratchet teeth 24b is achieved because the engagement on the first ratchet pole 25a side is achieved and at the same time, the apex 31b of the second ratchet pole 25b is Front edge 3 of second ratchet tooth 24b
It is when the vehicle has passed through 0b and beyond the apex 29b of the second ratchet tooth 24b into the inter-ratchet tooth space. Only in this way the engagement between the two ratchet pawls and the two ratchet teeth is achieved, so that a depth larger than that of the first ratchet pole 25a and the first ratchet tooth 24a by the Q dimension is obtained. If the second ratchet pole 25b does not plunge into the space between the ratchet teeth, complete engagement between both ratchet poles and both ratchet teeth can be achieved if a force in the reverse direction is applied to both ratchet poles. Can not.

Next, the operation procedure of the above embodiment will be described with reference to FIGS.

The apparatus of this embodiment is normally in the state shown in FIG. 4, and neither the penetrating shaft 16 nor the clamp cam 19 interferes with the seat belt 3, and the seat belt 3 is freely drawn out and wound up.

When the wire 18 is pulled in the direction of arrow P upon detecting a collision, the pulley 17 rotates in the direction of arrow B, and the clamp cam 19
The edge portion 19a of the abuts the seat belt 3. As a result, the clamp cam 19 pushes the seat belt 3 and tilts in the direction of arrow C as shown in FIG.
Seat belt 3 is caught between a and 20b. At this time, the seat belt 3 is pulled in the direction of arrow D by the edge portion 19a. The wire 18 is further pulled, and the end edge portion 19a of the clamp cam 19 further retracts the seat belt 3 (FIG. 9).

As described above, as a ratchet device for the winding device to which a relatively large torque acts, if it is provided only on one side of the rotary shaft, an unbalanced load will act and the shaft will be twisted, which is not preferable. However, even when two sets of ratchet mechanisms are provided, both ratchet wheels have the same tooth profile,
When manufactured with the same phase, if there is a slight angular error in the position of both teeth, there is a possibility that only one ratchet pole can be engaged, that is, between both ratchet wheels and ratchet pole. It is conceivable that a shift of one tooth will occur. Therefore, according to the present invention, as described above with reference to FIGS. 6 and 7, by making the shapes of the ratchet teeth 24a, 24b slightly different from each other, the apexes 29a, 29b of the ratchet teeth 24a, 24b are mutually different. ,
Providing a relative phase difference P between the apexes 31a, 31b of both ratchet poles 25a, 25b and thrusting the ratchet poles 25a, 25b into the ratchet interdental space necessary to achieve engagement. A difference Q is set in the quantity.

By the way, since the ratchet pole member 21 is always spring-biased toward the two ratchet wheels 15a and 15b, the two ratchet poles 25a and 25b move in accordance with the rotation of the two ratchet wheels 15a and 15b. , 24b, and repeat riding and dropping.

Since there is a deviation of P dimension in the circumferential direction between the apexes 29a, 29b of the two ratchet teeth 24a, 24b, FIGS.
The second ratchet pole 25b on the right side of the figure can be dropped into the inter-ratchet tooth space first, but the first ratchet pole 25a on the left side of FIGS. 6 and 7 still retains the first ratchet tooth 24a. Since it is on the front edge 30a, it does not actually fall into the ratchet interdental space. Further, for example, by tilting the ratchet pole member 21 or the like, the first ratchet pole 25
Even if the second ratchet pole 25b a little rushes into the ratchet interdental space before a, if the reverse rotation torque acts on the ratchet wheels 15a and 15b, the tip 29b of the second ratchet tooth 24b will move. Since it contacts the tapered surface 26 and the ratchet pole 25b is pushed out from the interdental space,
The second ratchet teeth 24b and the second ratchet pole 25b cannot be engaged with each other, and the ratchet teeth 25a, 25b are engaged with each other by the ratchet tooth one step before.

When the first ratchet pole 25a reaches a position where it can be dropped into the interdental space, there is a phase difference in the P dimension between the tips of the second ratchet pole 25b and the second ratchet tooth 24b, so both ratchets The pawls 25a and 25b easily drop into the ratchet interdental space and both can be completely engaged. Since the ratchet wheels 15a and 15b are in phase with each other in the tooth root positions, the ratchet poles 25a and 25b can be reliably connected to the trailing edge 28 of the ratchet teeth 24a and 24b.
Engages with a and 28b and does not cause twisting.

In the above embodiment, the bases of the trailing edges 28a, 28b of both ratchet teeth 24a, 24b are aligned with each other, and both apexes 29a, 29b are
The phase difference indicated by the P dimension is provided between them, but this is because the positions of the tooth vertices 29a and 29b coincide with each other as shown in FIG. A phase difference of P dimension may be provided at the position.

Further, the tapered surface 26 may also be applied to the apex of the corresponding ratchet teeth, and the shape is not limited to the above embodiment, and for example, it may be rounded or face the ratchet teeth of the ratchet pole. The entire surface may be cut off, or the entire outer circumference of one ratchet wheel may be cut off. That is, the same applies as long as gaps in the circumferential direction and the radial direction are formed between the vertices of the other tooth and the pole when the vertices of the one tooth and the pole match. The effect can be obtained, and in some cases, the ratchet pole is slightly bent, or the outer peripheral side of the ratchet teeth is bent inward or outward in the axial direction to provide a gap similar to the above. However, it may be contemplated to obtain a similar effect.

By the way, when a drive source that momentarily generates a large output such as explosive is used, the ratchet pole member 21 is repelled by the shocking torque at the time of start-up, which may hinder the reverse rotation prevention function. . Therefore, in this embodiment, the smooth portion 27 having no ratchet teeth is formed at the initial stage of rotation of the ratchet wheels 15a and 15b. This allows
At the time of starting, the ratchet pole member 21 can move smoothly along the outer peripheral surfaces of the ratchet wheels 15a and 15b, and it is possible to prevent the reverse rotation prevention function from being impaired by the dance of the ratchet pole member 21.

In each of the above-described embodiments, the present invention is applied to the reverse rotation preventing device in the winding mechanism accompanied by the rotary motion, but the present invention is applied as the retrograde preventing device between the two parts performing the relative linear motion. It can also be applied. FIG. 11 shows such an embodiment in a simplified manner.
Ratchet teeth 33a, 33b on the rails 32a, 32b of the book, respectively.
Is provided, and a ratchet pole member 34 having a pair of ratchet poles 35a and 35b that is spring-biased toward the ratchet teeth is tiltably supported in a direction in which the ratchet teeth approach and separate from the ratchet teeth.

Both ratchet teeth 33a, 33b are formed in the same phase with respect to the root of the tooth, but between the vertexes 36a, 36b of the ratchet teeth, due to the difference in the undercut shape of the trailing edges 38a, 38b The phase difference shown is provided.
Although the ratchet poles 35a and 35b have slightly different sharpnesses at their tips, none of them has the tapered surface as in the above embodiment. However, there is a difference indicated by the dimension Q between the tooth heights (H, H-Q) of both ratchet teeth 33a, 33b. Therefore, as in the above-described embodiment, one ratchet mechanism engages in accordance with the engagement operation of the other ratchet mechanism, so that it is possible to avoid the disadvantage that only one ratchet pole engages the ratchet teeth.

<Effects of the Invention> As described above, according to the present invention, it is possible to ensure the reliability of the operation without extremely increasing the manufacturing accuracy, and achieve the improvement of the manufacturability and the reliability of the ratchet device. It has a great effect on

[Brief description of drawings]

FIG. 1 is an overall configuration diagram around a seat belt to which the present invention is applied. FIG. 2 is an overall view of the webbing retractor. FIG. 3 is a top view showing an embodiment of the present invention with a part cut away. FIG. 4 is a sectional view taken along the line IV-IV in FIG. FIG. 5 is an enlarged perspective view of a main part. 6 and 7 are explanatory views showing the relationship between the ratchet teeth and the ratchet pole of this embodiment. FIG. 8 and FIG. 9 are sectional views similar to FIG. 4 showing the operation progress of this embodiment. FIG. 10 is an explanatory view similar to FIG. 6 showing the second embodiment. FIG. 11 is an explanatory view similar to FIG. 7 showing the third embodiment. 1 ... center pillar, 2 ... webbing retractor 3 ... seat belt, 4 ... through ring 5 ... seat, 6 ... end 7 ... tongue plate, 8 ... buckle 9 ... ELR device, 10 …… Traction device 11 …… Drive device, 12 …… Deceleration sensor 13 …… Webbing drum 14 …… Housing 15a, 15b …… Ratchet wheel 16 …… Thread shaft, 17 …… Pulley 18 …… Wire, 19 ...... Clamp cam 19a …… End edges 20a, 20b …… Clamp groove 21 …… Ratchet pole member 22 …… Hole 23 …… Tension coil springs 24a, 24b …… Ratchet teeth 25a, 25b …… Ratchet pole 26… … Tapered surface, 27 …… Smooth part 28a, 28b …… Rear edge 29a, 29b …… Vertex 30a, 30b …… Front edge 31a, 31b… Vertex 34 …… Ratchet pole member 35a, 35b …… Ratchet pole 36a, 36b, 37a, 37b ... Vertex 38a, 38b ... Trailing edge

Claims (4)

[Claims] 1. A pair of ratchet teeth fixed to a first common member in parallel to each other, and a second common member provided to engage with each ratchet tooth of the pair of ratchet teeth. And a pair of ratchet poles, which is a ratchet-type retrograde prevention device for limiting relative movement in one direction along the dentition direction between the members, one of the pair of ratchet poles The position in the dent row direction in which the ratchet interdental space of the corresponding tooth row can rush is the phase relative to the position in the dent row direction in which the other ratchet pole can rush into the ratchet interdental space of the corresponding tooth row. The amount of plunge that has a delay and is required for the one ratchet pole to engage with the ratchet teeth of the corresponding tooth row is equal to that of the other ratchet pole of the ratchet tooth of the corresponding tooth row. It is smaller than the inrush amount necessary to focus ratcheting backstop characterized by. 2. The ratchet according to claim 1, wherein the ratchet teeth corresponding to the one ratchet pole have a smaller cutting edge angle than the ratchet teeth corresponding to the other ratchet pole. Anti-reverse device. 3. The ratchet according to claim 1, wherein the ratchet tooth corresponding to the one ratchet pole has a tooth height larger than that of the ratchet tooth corresponding to the other ratchet pole. Anti-reverse device. 4. A taper surface is provided at an end of an engaging portion of the other ratchet pole with a ratchet tooth, and the taper surface is provided in any one of claims 1 to 3. Ratchet type retrograde prevention device.