JPH0320235Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a one-way rotation transmission mechanism for bicycle parts, specifically, the power of the driving body is transmitted to the driven body only when the driving body rotates in one direction. The present invention relates to a one-way rotation transmission mechanism for a bicycle component, which rotates the driven body by transmitting the transmission, and when the driving body rotates in the other direction, the driving body rotates freely relative to the driven body.

(Prior Art) In general, this type of unidirectional rotational transmission mechanism, as described in U.S. Pat. and those with dorsal grooves,
It consists of a C-shaped pawl spring that biases the transmission pawl in the direction of the ratchet teeth, and is used, for example, in freewheels.

A freewheel generally used for a bicycle has a cylindrical driving body with one or more sprockets supported around the outside of a cylindrical driven body so as to be freely rotatable by a pair of ball bearings. The ratchet teeth are provided on the inner circumferential surface between the ball bearings, and the transmission pawl is supported on the outer circumferential surface of the driven body between the ball bearings so as to be movable up and down via its base, and the pawl spring is fitted into a back groove provided at the center of the transmission pawl in the width direction to hold the transmission pawl. Note that the back groove of the transmission pawl is the seventh
As shown in the figure, there is a meshing part A at the center of the transmission pawl in the width direction.
It is formed from the end surface to the end surface of the base B, and the engaging portion A is divided in the width direction by this back groove C.

(Problems to be Solved by the Invention) However, when the unidirectional rotation transmission mechanism is incorporated into the freewheel as described above, if the ball bearings wear out or the ball pushing in the ball bearings loosens, The drive body provided with the ratchet teeth is inclined with respect to the axis of the driven cylinder depending on the way the drive chain is engaged with the sprocket, whereas the transmission pawl provided on the driven body is such that the end surface of the engaging portion Since it is held parallel to the axis of the driven body, the meshing surface of the ratchet tooth is inclined with respect to the end surface of the meshing portion of the transmission pawl.

As a result, when the driver depresses the pedal on a bicycle, etc., the driving body is rapidly rotated from a reversed state to a forward rotation relative to the driven body, and the power of the driving body is transmitted from the ratchet teeth to the driven body through the transmission pawl. In this case, an unbalanced load is applied to the transmission pawl in a direction that is inclined with respect to the end surface of the engaging portion of the transmission pawl, and the transmission pawl breaks from the thinned back groove portion or breaks in the width direction. There was a problem that the end face portion of the divided meshing portion was broken.

An object of the present invention is to prevent the transmission pawl from breaking even if an uneven load is applied to the transmission pawl.

(Means for Solving the Problems) Accordingly, the present invention provides ratchet teeth 1 on one side of the driving body and the driven body, and has an engaging portion 21 and a base portion 22 that mesh with the ratchet teeth 1 on the other side. In the one-way rotation transmission mechanism, the transmission pawl 2 is provided so as to be movable up and down via the base 22, and is provided with a C-shaped pawl spring 3 that biases the transmission pawl 2 in the direction of the ratchet tooth 1. 2 is formed in a continuous wide shape over the entire width, and a spring hook 23 that engages with the pawl spring 3 is provided on one side of the base 22.

(Function) Even if an unbalanced load is applied to the transmission pawl 2 due to the inclination of the driving body with respect to the driven body, the transmission pawl 2 is formed in a continuous wide shape over the entire width to improve durability and to prevent the meshing part from being damaged. Since the end face 21 is a wide face, it is possible to prevent the transmission pawl 2 from breaking due to the uneven load.

(Embodiment) The illustrated one is assembled into a freewheel, and includes a cylindrical drive body 6 having a plurality of sprockets 5 around the outer circumference of a cylindrical driven body 4 attached to the hub body of the rear hub. is freely rotatably supported by a pair of ball bearings 7 and 8, ratchet teeth 1 are provided around the inner peripheral surface between the ball bearings 7 and 8 in the drive body 6, and the ball bearing 7 in the driven body 4 is . A C-shaped claw spring 3 that biases in one direction is provided, and the outer peripheral surface of the driven body 4 includes a semicircular concave holding portion 41 that holds the base portion 22 and the engaging portion 21. A concave relief portion 42 for receiving the pawl spring 3 is continuously provided in the circumferential direction, and an annular spring groove 43 for accommodating the pawl spring 3.
has been established.

The ball bearing 7 is composed of a pair of ball races provided on the driven body 4 and the drive body 6, and a large number of balls interposed between these ball races. It consists of a ball race provided on the driving body 6, a ball pusher 81 having a ball race facing the ball race, and a large number of balls interposed between the ball races, and the ball pusher 81 is It is screwed onto a screw 45 provided axially outward of the holding portion 41 and relief portion 42 in the body 4 via a stepped portion 44 .
Further, a spacer 9 is interposed between the ball pusher 81 and the stepped portion 44, so that the ball pusher 81 can be fixed.

In the embodiment shown in FIGS. 1 to 4, the transmission pawl 2 is formed in a continuous wide shape over the entire width, and the pawl spring 3 is attached to one side of the base 22.
A spring hook 23 is provided which engages with the spring.

That is, the present invention eliminates the back groove provided in the conventional transmission pawl, and forms the transmission pawl 2 in a continuous wide shape across the entire width without being divided in the width direction, thereby improving durability. Engagement part 21 and base 2
2, a thin spring hanging piece 23 is provided on one side of the base 22, and the pawl spring 3 biases the ratchet tooth in the direction of the ratchet tooth 1.

Further, the pawl spring 3 is formed to have a short cross-sectional shape with a longer length in the width direction than the wall thickness, so that the spring hanging piece 23
The holding part 4 of the transmission pawl 2 is increased by increasing the contact area with the
It has good stability against 1.

Further, the spring groove 43 of the driven body 4 is provided on one side in the axial direction with respect to the holding portion 41 and the relief portion 42. Incidentally, this spring groove 43 is provided with a stopper 46 for stopping the rotation of the pawl spring 3.

In addition, in the illustrated example, a protrusion 24 that abuts the side surface of the spacer 9 is provided on the other side of the base 22 of the transmission pawl 2 to create a gap between the other side of the transmission pawl 2 and the spacer 9. is formed to prevent the other side surface portion of the engaging portion 21 of the transmission pawl 2 from interfering with the circumferential corner portion of the spacer 9 when the transmission pawl 2 is folded down.

Further, two transmission pawls 2 are formed, and these transmission pawls 2 are arranged at asymmetrical positions with respect to a straight line passing from the center between both ends of the pawl spring 3 to the axis, so that the lodging force of each transmission pawl 2 is reduced. We are trying to equalize it.

The present invention is constructed as described above, and the driving body 6
When the drive body 6 rotates in the normal direction, the power of the drive body 6 is transmitted to the driven body 4 via the ratchet teeth 1 and the transmission pawl 2.
The driven body 4 rotates together with the driving body 4. Further, when the driving body 6 is reversed, the transmission pawl 2 falls down against the pawl spring 3, the transmission pawl 2 is disengaged from the ratchet teeth 1, and the driving body 6 becomes free with respect to the driven body 4. It rotates.

Furthermore, due to wear of the ball bearings 7 and 8 or loosening of the ball pusher 81 in the ball bearings, the drive body 6 tilts with respect to the axis of the driven body 4, causing the ratchet teeth 1 provided on the drive body 6 to mesh with each other. With the surface inclined with respect to the engaging end surface 21a of the transmission pawl 2, the driving body 6 is rotated by depressing the pedal or the like.
When the transmission pawl 2 rapidly rotates in the normal direction relative to the driven body 4, an unbalanced load acts on the transmission pawl 2 in a direction that is inclined with respect to the end surface 21a of the engaging portion of the transmission pawl 2, as in the conventional case. The transmission pawl 2 is formed in a continuous wide shape over the entire width to increase durability, and the engaging portion end surface 21a is a wide surface.
This makes it possible to prevent the transmission pawl 2 from breaking due to the unbalanced load.

Moreover, since the pawl spring 3 is formed in a cross-sectional shape with a longer length in the width direction than the wall thickness, even though the spring hook 23 is provided on one side of the base 22, Not only can stability of the transmission pawl 2 with respect to the holding portion 41 be improved, but also movement of the transmission pawl 2 in the width direction can be prevented.Furthermore, since the wall thickness of the pawl spring 3 can be made thinner, the transmission pawl 2 can be prevented from moving in the width direction. The driven body 4 of the pawl spring 3 when the pawl spring 3 is lifted with respect to the spring groove 43 due to the collapse of the pawl spring 3
The amount of protrusion from the outer circumferential surface can be reduced, and it is also possible to form a pawl spring that is thin and has a large spring force.

In the embodiment described above, the driving body 6 is provided with the ratchet teeth 1 and the driven body 4 is provided with the transmission pawl 2, but it is also possible to provide the drive pawl 2 on the outside of the driven body 4. In addition to disposing the body 6, the driving body 6 may be disposed inside the driven body 4.

Furthermore, the unidirectional rotational transmission mechanism of the present invention is mainly incorporated into a unit hub, freewheel, internal transmission device, front free type gear crank device, and speed change operation device of a bicycle, but its usage is particularly limited. Not.

(Effects of the invention) As described above, the present invention provides a power transmission pawl 2 having an engaging portion 21 and a base portion 22 that mesh with the ratchet teeth 1.
is formed into a continuous wide shape over the entire width, and a spring hook 23 that engages with the pawl spring 3 is provided on one side of the base 22, so that the transmission pawl may be bent due to the inclination of the driving body with respect to the driven body. Even if an unbalanced load acts on the transmission pawl 2, it is possible to prevent the transmission pawl 2 from breaking due to the unbalanced load.

[Brief explanation of the drawing]

Fig. 1 is a vertical side view showing an example of the mechanism of the present invention incorporated into a feed-wheel, Fig. 2 is an enlarged front perspective view of only the transmission claw, Fig. 3 is an enlarged rear perspective view of the same, Fig. 4 is an enlarged longitudinal sectional front view corresponding to Fig. 1, Fig. 5 is a partially cutaway front view of only the driven body, and Fig. 6 is a partially cutaway front view of only the driven body.
The figure is a side view of the same, and FIG. 7 is a perspective view of only the transmission pawl showing a conventional example. 1... Ratchet tooth, 2... Transmission pawl, 21...
Engaging portion, 22... base, 23... spring hanging piece, 3...
...claw spring.

Claims (1)

[Scope of utility model registration request] Ratchet teeth 1 are provided on one side of the driving body and the driven body, and a meshing portion 2 that meshes with the ratchet teeth 1 is provided on the other side.
1 and a base 22, the transmission pawl 2 is connected to the base 22.
The transmission pawl 2 is provided so as to be raised and lowered through the
In the one-way rotation transmission mechanism provided with a C-shaped pawl spring 3 that biases the ratchet tooth in one direction,
The transmission pawl 2 is formed in a continuous wide shape over the entire width, and the pawl spring 3 is attached to one side of the base 22.
A one-way rotational transmission mechanism for a bicycle component, characterized in that a spring hook 23 is provided which engages with the spring hook 23.