JPS6223172B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a unit hub for a bicycle, and more particularly, a unidirectional rotation transmission mechanism that allows the hub body to rotate in only one direction with respect to a drive body equipped with a sprocket wheel, and a hub configuration including the drive body. This invention relates to an improvement in a unit hub for a bicycle, which has a unitized bearing mechanism for supporting the body of the bicycle in a freely rotatable manner with respect to the hub shaft.

[Conventional technology]

The conventional general configuration of this type of unit hub is shown in JIS D9419. Comparing this with the structure of a normal hub with a freewheel, which is constructed by screwing a separately formed freewheel to the hub body attachment part, the unit hub has a freewheel core and a hub body in the hub with a freewheel. It has a rough structure that seems to be an integrated structure. Although the structure and manufacturing of such a unit hub can be simplified by configuring it as described above, it is a one-way rotation system that transmits the driving force of a drive body equipped with a sprocket to the hub body in only one direction. As the transmission mechanism, a so-called ratchet mechanism consisting of a ratchet tooth row provided on the inner periphery of the drive body and a ratchet pawl semi-embedded in the core is used, and the structure thereof is quite complex. For this reason, various unit hubs have been proposed in which the conventional unidirectional rotation transmission mechanism, the ratchet mechanism, is changed to a simple one using a friction clutch (Japanese Utility Model Publication No. 7863/1983, Utility Model Application Publication No. 1983/1983).
63156, JP-A-51-69847, etc.). These unit hubs are provided with a conical inner surface of the clutch on the inner peripheral surface of the right end of the hub body, and are screwed onto a threaded shaft portion in the inwardly extending portion of a drive body equipped with a sprocket so as to be movable in the hub axial direction. The clutch cone is generally constructed by providing on the outer periphery of the clutch cone a conical outer surface which can be fitted into the inner surface of the clutch in a male-female manner. Furthermore, the clutch cone is usually provided with a spring or the like to provide a certain amount of frictional resistance to rotation relative to the hub shaft or hub body. In this configuration, when the pedal crank is depressed, the drive body is rotated in the forward direction (clockwise when viewed from the right side of the bicycle) through the drive chain.
(The same applies hereinafter), the clutch cone, which is given frictional resistance as described above and is difficult to rotate relative to the hub axle, is threaded onto the screw shaft of the rotating drive body toward the inner surface of the clutch. The outer surface of the clutch and the inner surface of the clutch are in close contact with each other, and the rotational force of the drive body is transmitted to the hub body. However, when the drive body is reversed (counterclockwise when viewed from the right side of the bicycle, the same applies hereinafter), the rotational force is opposite to the above. Next, the clutch cone is threaded on the screw shaft in a direction away from the inner surface of the clutch, and the inner surface of the clutch and the outer surface of the clutch are separated from each other. In this way, the clutch device, which consists of the inner surface of the clutch on the inner surface of the hub body, the clutch cone that is screwed by the rotation of the drive body and moves in the hub axis direction, and the outer surface of the clutch formed on the outer periphery of the clutch cone, is similar to the conventional freewheel. It has a unidirectional rotation transmission function similar to the ratchet mechanism in the attached hub.

[Problems to be solved by the invention]

However, the unit hub using the above clutch device has various problems as follows. First of all, in order to reliably transmit the powerful rotational force of the drive body to the hub body, the slope of the taper on the inner and outer surfaces of the clutch should be made quite gentle, and a wedge effect should be used when the two clutch surfaces are joined. It is necessary to increase the surface pressure between both clutch surfaces to obtain sufficient frictional force. However, if the rotational force of the drive body is too strong, the outer surface of the clutch wedges into the inner surface of the clutch and cannot be separated, causing the drive body or hub body to become strongly integrated, causing the drive body to reverse relative to the hub body. It may become impossible. In order to prevent such sticking between the inner and outer surfaces of the clutch, it is possible to make the slope of the taper of both clutch surfaces steeper, but this will increase the contact surface pressure that occurs when the two clutch surfaces are joined. Frictional force is insufficient, and the rotational driving force of the drive body cannot be sufficiently transmitted to the hub body. In this way, if the clutch device as described above transmits sufficient rotational driving force during normal rotation, the clutch disengages during reverse rotation, and
Improving clutch disengagement during reverse rotation has a fundamental drawback in that slippage occurs on the clutch surface, making it impossible to transmit sufficient rotational force during forward rotation.
Furthermore, even if the viscosity of the lubricating oil used is slightly changed, or if the amount of the lubricating oil decreases even slightly, the frictional force generated between the two clutch surfaces will change significantly, so the viscosity of the lubricating oil must be strictly controlled during manufacturing. , and requires frequent lubrication or seasonal maintenance on the part of the general user. Second, as mentioned above, as a result of having to make the taper of the inner and outer surfaces of the clutch gentler, the axial length of the clutch cone becomes longer, and this increases the weight of the clutch cone, causing friction in its rotation. Since the spring for applying force also needs to be large, the members are generally large, and the mechanism cannot be made compact, and the clutch operation response cannot be improved. Furthermore, the same can be said about conventional unit hubs or hubs with freewheels, but for example in bicycle parking lots,
When pushing a bicycle backwards, the hub body becomes the driving side and rotates in reverse, which causes the driving body to reverse, so the pedal crank always rotates in reverse. In other words, in a conventional unidirectional rotation transmission mechanism such as a ratchet mechanism in the rear hub of a bicycle, the hub body is configured to freely rotate in the normal direction relative to the drive body, so when pushing the bicycle forward, Even if the hub body rotates in the normal direction, the sprocket, the chain suspended from it, and the pedal crank remain stationary, but since the hub body is configured so that it cannot rotate relative to the driving body, it is impossible to leave the bicycle behind. When pushing back,
When the hub body is reversed, the drive body, sprocket or pedal crank are also reversed accordingly. In this way, all bicycles equipped with a conventional one-way rotation transmission mechanism have pedals that rotate in the opposite direction when pushing back the bicycle body. When pushing a bicycle out from behind, the rotating pedal crank may hit an adjacent bicycle, making it extremely difficult to get the bicycle out. The present invention was devised under the above circumstances, and its object is to provide a unit hub for a bicycle that solves the problems of the prior art described above.

[Means to solve the problem]

In order to solve the above problem, the present invention takes the following technical measures. That is, the present invention includes: a hub axle; and a rotatably supported hub axle at one end thereof;
A driving body having a sprocket on the outside and a threaded shaft portion on the inside, rotatably supported on the inner periphery of both ends by the other end of the hub shaft and the outer periphery of the driving body, and axially supported on the inner periphery of the driving body side. A hub body having a conical inner surface of the clutch whose diameter increases toward the inside; and a hub body that is threadedly engaged with the helical shaft portion so as to be threaded toward the inner surface of the clutch when the helical shaft portion rotates in the normal direction; a clutch cone having a conical outer clutch outer surface that can be tightly fitted; and a bicycle unit hub comprising: a clutch inner surface of the hub body and a clutch outer surface of the clutch cone; Engagement protrusions having ratchet teeth in cross section and facing oppositely to each other are provided so that they can engage with each other when relative forward rotation is attempted, and the clutch cone is always elastically biased in a direction away from the inner surface of the clutch.

[Effect]

When the drive member is driven to rotate in the normal direction, the clutch cone screwed onto the screw shaft portion of the drive member is sent toward the inner surface of the clutch of the hub body, and the outer surface of the clutch and the inner surface of the clutch are eventually joined. At this time, the clutch cone can no longer move in the direction of the hub axis on the screw shaft, so it begins to rotate together with the drive body, but since the above-mentioned engaging projections are provided on the outer and inner surfaces of the clutch, During mutual connection, normal rotation of the outer surface of the clutch relative to the inner surface of the clutch is not allowed, so the outer surface of the clutch on the clutch cone side does not slip against the inner surface of the clutch on the hub body side, and the forward rotation driving force of the drive body is ensured. is transmitted to the hub body. On the other hand, when the pedals are stopped or reversed while driving, the hub body or the inner surface of its clutch tends to rotate forward due to inertia. Push in the same direction to force the clutch cone to rotate forward. Here, the screw shaft of the drive body is threaded so that when it rotates in the forward direction, the clutch cone is threaded toward the inner surface of the clutch, so the screw shaft is either stopped or rotating in the opposite direction. In contrast, when the clutch cone is rotated in the forward direction as described above, the clutch cone moves on the screw shaft in a direction away from the inner surface of the clutch. Moreover, since this clutch cone is always elastically biased in the direction away from the inner surface of the clutch on the hub body side, the separation of the outer surface of the clutch cone from the inner surface of the clutch on the hub body side and subsequent movement on the spiral shaft is prevented. It is done extremely smoothly. This means that when transitioning to free running, the clutch disengages between the clutch outer surface and the clutch inner surface very quickly.

【effect】

The outer surface of the clutch of the clutch cone, which is screwed when the drive body rotates in the normal direction, and the inner surface of the clutch on the hub body side do not simply come into frictional contact, but the oppositely directed ratchet tooth-shaped engagement protrusions provided on both sides engage with each other. As a result, the driving force is transmitted to the hub body, so that even if the slope of the taper of both clutch surfaces is increased, the driving force can be reliably transmitted to the hub body.
Therefore, the problem of sticking when reducing the taper inclination angle in order to increase the contact surface pressure between both clutch surfaces as in the prior art is conveniently solved. By providing the engaging protrusion on the outer surface of the clutch on the clutch cone side and the inner surface of the clutch on the hub body side, the engaging protrusion on the hub body or the inner surface of the clutch, which rotates in the normal direction, moves the engaging protrusion on the outer surface of the clutch in the same direction. The clutch cone is forced to rotate in the normal direction by pushing, and since the clutch cone is always elastically biased in the direction away from the inner surface of the clutch, the clutch cone moves extremely smoothly on the screw shaft in the direction away from the inner surface of the clutch. , when the drive body is stopped or reversed while the vehicle is running, the clutch is disengaged instantaneously. In view of the above, according to the present invention, a unidirectional rotation transmission in a bicycle unit hub is achieved by connecting and separating the clutch cone screw-fed by the rotation of the drive body and the clutch surface on the hub body side. The mechanism has high driving force transmission performance,
This is an unprecedented product that combines smooth clutch disengagement performance. Moreover, in the present invention, in addition to the above effects,
This has an extremely excellent effect in that the pedals do not rotate even when pushing the bicycle body backwards, but since the operation is delicate and complicated, this will be described in the description of the embodiment below.

[Explanation of Examples]

Embodiments of the present invention will be specifically described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a hub body, which cooperates with a clutch member 2 that is integrally fitted into and fixed to the enlarged diameter portion 3 at the right end of the hub body to constitute the entire hub body.
4 has a sprocket 5 (this includes both a so-called single sprocket consisting of only one sprocket and a so-called multi-stage sprocket consisting of a plurality of sprockets with different numbers of teeth arranged side by side) on the outer right end. 6 is the driving body 5
A clutch cone is shown which is screwed onto a screw shaft portion 7 formed in an inwardly extending portion of the clutch cone and which is movable back and forth in the direction of the hub axis by rotation of the drive body 4. The driving body 4 has a wand 8 formed on its outer and inner periphery.
By interposing a rollable steel ball 11 between the hub body 1 and the convex ball 10 screwed to the hub axle 9, the hub body 1 can be rotated with respect to the hub axle 9.
The clutch member 2 is located between the one 12 provided on the inner periphery of the left end of the hub body 1 and the cone 13 screwed onto the left end of the hub shaft 9, and between the clutch member 1
By interposing steel balls 17 and 16 between the ball receiver 14 formed on the outer inner periphery of the sprocket 2 and the ball receiver surface 15 formed on the inner shoulder of the sprocket 5 of the drive body 4, the hub shaft It is possible to rotate relative to both the drive body 9 and the drive body 4. However, due to the one-way rotation transmission mechanism 18 described below,
The hub body 1 is basically configured so that it can rotate in the normal direction relative to the drive body 4, but not in the reverse direction. The one-way rotation transmission mechanism 18 has a conical inner surface 19 and a conical outer clutch outer surface 20 formed on the inner circumferential surface of the clutch member 2 and the outer circumference of the clutch cone 6 so as to fit into each other in a male-female manner. At the same time, the clutch cone 6
The screw shaft 7 is generally configured so that the screw is fed in the direction of the hub axis. In addition, the hub body 1
The clutch inner surface 19 of the side clutch member 2 has a conical inner surface shape whose diameter increases toward the inside, and the clutch outer surface 20 on the clutch cone 6 side has a conical outer surface shape corresponding to the clutch inner surface 19. . In this example, during normal rotation driving, the drive body 4 rotates clockwise when viewed from the right side of the bicycle, and since the clutch inner surface 19 is formed on the right side of the hub body, the screw shaft 7 is a right-handed thread,
Therefore, when the drive body 4 rotates normally relative to the clutch cone 6, the clutch cone 6 is sent in the direction of arrow P in FIG. When the clutch cone 6 is reversely rotated relative to the clutch cone 6, the clutch cone 6 is moved in the direction of arrow Q in FIG. 1, and the clutch inner surface 19 and the clutch outer surface 20 are separated from each other. In the present invention, both the clutch inner surface 19 and the clutch outer surface 20 are provided with engaging protrusions 25 and 26, respectively, which engage with each other and have ratchet teeth in cross section in opposite directions. This example will be explained based on FIGS. 2a to 4. As can be seen, the angle of taper of the clutch inner surface 19 and the clutch outer surface 20 is considerably greater than that of conventional clutch devices of this type, and is preferably greater than approximately 30 DEG. In the illustrated example, the angle is set to 45°. As a result, even if the clutch inner surface 19 and the clutch outer surface 20 are pressed against each other, a phenomenon in which the clutch outer surface wedges against the clutch inner surface and cannot be separated from the clutch inner surface, as in the conventional example, does not occur. As shown in FIG. 4, the clutch inner surface 19 includes:
As shown in FIG. 4, a ratchet tooth-shaped engagement protrusion 25 is continuously provided which slopes radially inward as it goes counterclockwise and then gradually steps radially outward, and as shown in FIG. is provided here and there with ratchet tooth-shaped engaging portions 26 which slope outward in the radial direction and then step inward in the radial direction as one goes in the clockwise direction. Figures 3 and 4
When the figures are superimposed, it can be seen that when the clutch inner surface 19 and the clutch outer surface 20 are joined to each other, relative reversal of the clutch member 2 with respect to the clutch cone 6 is not allowed. In other words, the driving force for normal rotation (clockwise rotation in FIG. 3) of the clutch cone 6 is
5 and 26, which means that the transmission is reliably transmitted to the clutch member 2 or the hub body 1 by engaging with each other. Contrary to the illustrated example, the engaging protrusions 25 and 26 may be provided at various places in the circumferential direction on the inner surface of the clutch, while the engaging protrusions 26 on the outer surface of the clutch may be provided continuously. , both 2
Both 5 and 26 may be provided continuously. Further, the cross-sectional shape of the engaging protrusion may be in various configurations, such as a sawtooth shape as shown in the illustrated example, or an aquiline shape in which an inclined surface, an inner circumferential surface, and a radial stepped portion are continuous. Furthermore, in the present invention, the clutch cone 6 is always elastically biased in a direction away from the clutch inner surface 19, that is, in the illustrated example, in the direction of arrow Q in FIG. be able to. A cylindrical space 28 is provided between the inner hole 27 of the screw shaft portion 7 of the drive body 4 and the hub shaft 9, and a compression coil spring 21 is interposed in this space 28 so as to be inserted into the hub shaft 9. The elasticity of the compression coil spring 21 is used to bias the clutch cone 6. The outer end of the compression coil spring 21 is brought into contact with, for example, the inner end wall of the cone spring 10 and is slightly reduced in diameter so as to be elastically wound around the hub axle 9, while the inner end 21a is brought into contact with the hub axle 9. It is engaged with an engaging portion of a donut disk-shaped friction plate 22 that is fitted so as to be slidable in the axial direction. Furthermore, the inner wall of the outer circumferential portion of the donut disc-shaped friction plate 22 is brought into contact with the outer wall of a retaining ring 23 fitted into the inner circumference of the clutch cone 6. In this way, due to the elasticity of the compression coil spring 21, the friction plate 22, which is constantly pushed in the direction of the arrow Q in FIG. 1, pushes the retaining ring 23 in the direction of the arrow Q in FIG.
is always elastically biased in the direction of arrow Q in FIG. At the same time, the compression coil spring 2
Since the outer end of the friction plate 1 is elastically wrapped around the hub axle 9, it does not rotate relative to the hub axle, and the friction plate 2
Since the friction plate 22 is engaged with the compression coil spring, the friction plate 22 is also difficult to rotate relative to the hub shaft 9. Since this friction plate 22 comes into frictional sliding contact with the retaining ring 23 of the clutch cone 6, a constant frictional resistance is applied to the rotation of the clutch cone 6 with respect to the hub shaft 9. That is, the clutch cone 6 always tries to remain stationary with respect to the hub shaft 9. When the force trying to rotate the clutch cone 6 exceeds the frictional force between the retaining ring 23 and the friction plate 22, the retaining ring 23 or the clutch cone 6
slides and rotates with respect to the friction plate 22. The outer end of the compression coil spring 21 may be elastically wound around the hub shaft 9 as shown in the figure, or may be engaged with a suitable engagement portion provided on the ball pusher 10. . In addition, in the illustrated example, by providing a compression coil spring on the right side of the friction plate 22 in FIG.
This friction plate 22 is pushed in the direction of the arrow Q in FIG. 1. By providing a tension coil spring (not shown) on the left side of the friction plate 22 in FIG. It may be pulled elastically. Incidentally, reference numeral 24 in the figure indicates a stopper for preventing the clutch cone 6 from moving too far inward. In addition, the friction plate 22 is omitted, and the inner end of the compression coil spring 12 in the figure is connected to the retaining ring of the clutch cone 6.
3, and attach it to the retaining ring 23.
It may be brought into elastic contact with. Next, the operation of the illustrated unit hub will be explained. FIG. 6 shows the clutch cone 6 in its most inward movement. At this time, the clutch inner surface 19
Since the clutch outer surface 20 and the clutch outer surface 20 are separated from each other,
The hub body 1 can rotate freely in the normal direction with respect to the drive body 4.
Therefore, while the bicycle is running, the bicycle can coast while the driving body 4 is stopped, or the driving body 4 can be actively reversed while the bicycle is traveling or when the bicycle is stopped. When the driver 4 is rotated in the normal direction by depressing the pedal, the clutch cone 6 is provided with a certain resistance to rotation relative to the hub shaft 9, so the driver 4 rotates in the normal direction relative to the clutch cone 6. Then, the clutch cone 6 moves on the screw shaft 7 of the drive body 4 as shown by the arrow P.
The clutch outer surface 20 and the clutch inner surface 19 are joined together (FIG. 1). When the clutch outer surface 20 and the clutch inner surface 19 are joined together, the clutch cone 6 cannot advance any further in the direction of arrow P, so it begins to rotate together with the drive body 4, and both clutch surfaces 19, 20 engage with their engaging protrusions 25, 26 are engaged and the clutch inner surface 19 cannot be rotated relative to the clutch outer surface 20. Therefore, the clutch cone 6, which rotates in the normal direction, rotates the clutch member 2 or the hub body 1 at the same speed. The bicycle is accelerated forward. Transmission of the rotational force from the clutch outer surface 20 to the clutch inner surface 19 is carried out by the engagement of the engagement protrusions 25 and 26, so that it is reliably carried out without slippage. On the other hand, in the driving state shown in FIG. 1, when the pedal is stopped to stop the driving body, the hub body 1 rotates in the normal direction relative to the driving body 4, but the clutch inner surface 19 and the clutch Since the outer surface 20 has engaging protrusions 25 and 26 having a predetermined height that engage with each other, the inclined surfaces 25a and 26a of the engaging protrusions 25 and 26 are pushed against each other, and the clutch cone 6 is forced to slightly tilt. It rotates in the normal direction together with the hub body 1, and is sent in the direction of arrow Q on the screw shaft 7 of the drive body 4. When the clutch inner surface 19 and the clutch outer surface 20 are disengaged, the clutch is completely disengaged. In this case, the clutch cone 6 is constantly pushed by the compression coil spring 21 in the direction of arrow Q in FIG. There is less resistance if the shaft is rotated in the normal direction and sent in the direction of arrow Q. Therefore, the above-mentioned co-rotating normal rotation is performed extremely smoothly, and the clutch disengagement is very easy. Further, in the bicycle unit hub according to the present invention, since the clutch cone 6 is pressed in the direction of the arrow Q by the spring 21 as described above, the engagement between the clutch inner surface 19 and the clutch outer surface 20 is once released. Then, unless the driving body 4 is rotated in the normal direction relative to the hub axle, the two clutch surfaces will not engage with each other again. Therefore, when the clutch is disengaged, the drive body or pedal clutch does not rotate whether the bicycle body is pushed forward or backward. To fully disengage the clutch, simply push the bicycle slightly forward without turning the pedal crank, so when parking the bicycle, etc.
Very convenient. That is, when parking the bicycle, the bicycle must be pushed forward to fit into the desired space, so the clutch automatically disengages lightly and completely, and then the bicycle is pushed backwards and pulled out. In this case, the pedal crank will not turn. As a result, the problem of conventional bicycles equipped with freewheels with a ratchet mechanism, where the pedal crank reverses when pulling the bicycle body backwards and collides with an adjacent bicycle, is solved at once. . As described above, the bicycle unit hub according to the present invention is a hub that has a simple structure, eliminates ratcheting noise during free rotation, and breaks the conventional wisdom that the pedal does not rotate when pushing back the bicycle body. Moreover, the unidirectional rotation transmission mechanism has reliable on/off operation, and reliability has been dramatically improved. Furthermore, since the mechanism is simple, manufacturing costs are low and the structure can be compact.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a partially sectional view, FIG. 2a is a partially sectional view of the clutch cone,
Fig. 2b is a partial sectional view of the clutch member, Fig. 2c is a partial sectional view of the drive body, and Fig. 3 is a - of Fig. 2a.
Figure 4 is a cross-sectional view taken along the - line in Figure 2b, Figure 5 is a perspective view showing the components in an exploded state, and Figure 6 is a part showing the state where the clutch cone has moved inward most. FIG. DESCRIPTION OF SYMBOLS 1... Hub body, 4... Drive body, 5... Sprocket, 6... Clutch cone, 7... Spiral shaft part, 1
9...Clutch inner surface, 20...Clutch outer surface, 2
5... Engagement protrusion (on the inner surface of the clutch), 26...
Engagement protrusion (on the outside of the clutch).

Claims (1)

[Claims] 1. A hub axle; rotatably supported at one end of the hub axle;
A driving body having a sprocket on the outside and a threaded shaft portion on the inside, rotatably supported on the inner periphery of both ends by the other end of the hub shaft and the outer periphery of the driving body, and axially supported on the inner periphery of the driving body side. A hub body has a conical inner clutch inner surface whose diameter increases toward the inside, and the helical shaft part is provided with a hub body having a conical inner surface that increases in diameter toward the inside. A bicycle unit hub comprising: a clutch cone having a conical outer clutch outer surface that is screwed so as to be threaded toward the inner surface of the clutch when rotating in the same direction, and that can tightly fit with the inner surface of the clutch; Both the inner surface of the clutch of the hub body and the outer surface of the clutch of the clutch cone are provided with engagement protrusions having ratchet teeth in cross section facing in opposite directions and capable of engaging with each other when the outer surface of the clutch attempts normal rotation relative to the inner surface of the clutch. A unit hub for a bicycle, characterized in that the clutch cone is always elastically biased in a direction away from the inner surface of the clutch.