Free wheel capable of steplessly varying speed

Abstract

To provide a free wheel that transmits rotation in one direction by steplessly varying a speed.SOLUTION: A free wheel mechanism, which has a ratchet mechanism between an active rotor and a passive rotor, transmits rotation in only one direction. The active rotor holds one of a pawl and a tooth, which are components of the ratchet mechanism, and the passive rotor holds the other one. The pawl of the ratchet mechanism can oscillate in a rotary shaft direction of the rotor for holding it. The tooth of the ratchet mechanism protrudes in the rotary shaft direction of the rotor for holding it. Rotary shafts of the active and passive rotors can become eccentric.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a freewheel. [Background technology]

[0002] Conventional freewheels are mechanisms that transmit rotation in one direction at a constant speed, and require a separate transmission mechanism to change speeds. Summary of the Invention [Problem to be solved by the invention]

[0003] To provide a freewheel which transmits rotation in one direction and at a steplessly variable speed. [Means for solving the problem]

[0004] To achieve the above object, the infinitely variable speed freewheel is characterized in that, in the freewheel mechanism that transmits rotation in only one direction, a ratchet mechanism is provided between an active rotating body and a passive rotating body, one of the pawls and teeth that are components of the ratchet mechanism is held by the active rotating body and the other is held by the passive rotating body, the pawls of the ratchet mechanism can swing in the direction of the rotation axis of the rotating body that holds them, the teeth of the ratchet mechanism protrude in the direction of the rotation axis of the rotating body that holds them, and the rotation axes of the active rotating body and the passive rotating body can be eccentric. [Effects of the Invention]

[0005] It is possible to provide a freewheel that transmits rotation in one direction and at a steplessly variable speed. [Brief explanation of the drawings]

[0006] [Figure 1] Principle diagram of accelerating and transmitting rotation in one direction [Figure 2] Principle diagram of transmitting rotation in one direction at a uniform speed DETAILED DESCRIPTION OF THE INVENTION

[0007] Generally, a freewheel is a mechanism that has a ratchet mechanism between the driven sprocket and hub of a bicycle and transmits rotation in only one direction, but here, since it is not limited to a bicycle chain drive mechanism, the driven sprocket is the active rotating body and the hub is the passive rotating body. Generally, a ratchet mechanism consists of a gear and a pawl that meshes with the gear's teeth to prevent the gear from rotating. The gear's teeth are inclined in one direction around the gear's rotation axis, and the pawl is biased by a spring or the like so that it meshes with the gear's teeth. The overall shape of the gear is generally an internal gear or spur gear in which the teeth protruding in a direction intersecting the rotation axis of the gear are inclined in one direction around the rotation axis, but in this case, the teeth protruding in the direction of the rotation axis of the gear are in the shape of a crown gear in which the teeth protruding in the direction of the rotation axis are inclined in one direction around the rotation axis. The following description will be given assuming an embodiment in which the active rotating body holds the pawl and the passive rotating body holds the teeth. The passive rotating body has a shape in which multiple teeth are held in a gear shape around its rotation axis, but since the rotation axis of the multiple gear-shaped teeth coincides with that of the passive rotating body and they operate as a single unit, for the purpose of explanation, they will not be called gears, but will be collectively called the passive rotating body together with the passive rotating body that holds them. To accommodate the eccentricity of the rotation axes of the active and passive rotors, the tooth width is wider in the direction perpendicular to the rotation axis of the passive rotor, but it does not have to be strictly perpendicular, nor does it have to be straight in the tooth width direction. The more claws and teeth that can be arranged, the smoother the operation will be, but there is no limit to the number. The range of the gear ratio is proportional to the turning radius of the pawl.

[0008] Its operation as a freewheel is similar to that of a general freewheel; when the rotation of the active rotor is relatively faster than that of the passive rotor, the pawls engage with the teeth and transmit the rotation of the active rotor to the passive rotor. However, when the rotation of the active rotor is relatively slower than that of the passive rotor, or when the rotation is reversed, the tips of the pawls slide along the tooth surfaces that are inclined around the rotation axis of the passive rotor, oscillating in the direction of the tooth protrusions and climbing over the teeth, so that the rotation of the active rotor does not affect the rotation of the passive rotor, and as a result, rotation is transmitted in only one direction. This operation is the same even when the rotation axes of the active and passive rotating bodies are eccentric.

[0009] In operation as a continuously variable transmission, when the rotation axes of the active and passive rotors are eccentric, the distance between the position where the pawl contacts the tooth and the rotation axis of the passive rotor changes with rotation. Among the multiple pawls, the pawl that comes into contact with the tooth at a position closest to the rotation axis of the passive rotor engages with the tooth to drive the tooth. At this time, since the radius of rotation of the pawl is longer than the distance between the position where the pawl meshes with the tooth and the rotation axis of the passive rotating body, the rotation angle of the tooth relative to the rotation axis of the passive rotating body becomes larger than the rotation angle of the pawl relative to the rotation axis of the active rotating body, and the rotation is transmitted at an increased speed. Then, as the rotor rotates, the position where the driving claw contacts the teeth moves away from the rotation axis of the passive rotor. As a result, the rotation speed of the passive rotor slows down, and one of the other pawls approaches the rotation axis of the passive rotor, catches up with the tooth in front of it, and the contacting pawl engages with the tooth to drive it, repeating this process. The position where the pawls and teeth come into contact constantly changes depending on the number of pawls, the number of teeth, the eccentricity distance, and the rotation, and the pawls and teeth do not mesh only at the point closest to the rotation axis of the passive rotating body, but also in the vicinity thereof. Even if the claws other than the ones that mesh with the teeth to drive them come into contact with the teeth, they are relatively far from the rotation axis of the passive rotating body and rotate slower than the teeth at the contact position, so they are overtaken by the teeth due to the operation of the freewheel mechanism and do not affect the rotation of the passive rotating body. By increasing the number of pawls and teeth, the range in which they mesh and drive is narrowed, the rotation of the passive rotor is made closer to a constant speed, and friction and resistance caused by the relative movement of the meshing pawls and teeth can be reduced. Although the rotational speed transmitted is not strictly constant, this does not cause any problems in applications such as bicycles. The shape of the teeth in the tooth width direction may not be linear with respect to the direction perpendicular to the rotation axis of the passive rotating body, but may be inclined or curved with respect to the direction intersecting the rotation axis of the passive rotating body, with the positions farther from the rotation axis deviating more in the rotation direction than the positions closer to the rotation axis at each part of the tooth width. In this case, the pawl moves away from the tooth faster when it moves away from the rotation axis of the driven rotor as it rotates, and approaches the tooth faster when it moves closer to the rotation axis of the driven rotor. Due to eccentricity, the position where the pawl engages with the tooth moves during operation, causing friction between the tip of the pawl and the surface of the tooth, resulting in wear and resistance. As a countermeasure, it is desirable to make the tip of the claw a rotating body such as a roller, as shown in the figure.

[0010] For the purpose of shifting gears, the means for eccentrically positioning the rotation axes of the active rotor and the passive rotor can be forced, but as described above, if the teeth are inclined or curved in the tooth width direction and the tooth surfaces that come into contact with the pawls are inclined, the component of the force with which the pawls drive the teeth will move the rotation axis of the active rotor that holds the pawls in a direction closer to the rotation axis of the passive rotor that holds the teeth, resulting in an automatic shift in which the gear ratio changes according to the rotational load. In this case, the active rotor is biased with a constant force in the direction of an eccentric position relative to the passive rotor, but the negative force can also be made variable. [Explanation of symbols]

[0011] 1 Active Rotor 2 Passive Rotating Body 3 Claws 4 rollers 5 teeth

Claims

[Claim 1] A ratchet mechanism is provided between the active rotating body and the passive rotating body, In a freewheel mechanism that transmits rotation in only one direction, The active rotating body holds one of the pawl and the tooth, which are components of the ratchet mechanism, The other is held by the passive rotating body, The pawl of the ratchet mechanism is swingable in the direction of the rotation axis of the rotating body that holds it, The teeth of the ratchet mechanism protrude in the direction of the rotation axis of the rotating body that holds the ratchet mechanism, The rotation axes of the active rotating body and the passive rotating body are eccentric. Infinitely variable speed freewheel.

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