EP-4737293-A1 - VARIABLE-SPEED HUB

EP4737293A1EP 4737293 A1EP4737293 A1EP 4737293A1EP-4737293-A1

Abstract

The present invention relates to a variable-speed hub, including a hub housing, a first-level drive component, and a second-level drive component. The second-level drive component includes a second clutch and a second spline. The second clutch is fixed to the hub housing via a second pawl and rotates along with the hub housing, to achieve power transmission. The second pawl is located on an outer peripheral side of the second spline. The present invention provides an effective coupling and decoupling mechanism, and the second pawl, when overtaking a plurality of spline parts, can decouple from an external spline through the design of a drive arm. Additionally, the external spline includes a plurality of spline parts and a slope surface, providing smooth coupling and decoupling operations. The present invention provides a variable-speed hub with compact structure and reliably operation, which can be applied in various mechanical transmission systems.

Inventors

WU, ZHIGUO
WANG, XIAOHONG

Assignees

Kunshan Karasawa Clean Energy Technology Co., Ltd

Dates

Publication Date: 20260506
Application Date: 20231015

Claims (10)

A variable-speed hub, comprising: a hub housing, a first-level drive component, directly driving the hub housing via a first pawl, and a second-level drive component, connected to the first-level drive component via a planetary gear set, wherein, the second-level drive component comprises a second clutch, the second clutch being fixed to the hub housing, rotating along with the hub housing, and being used for driving a second spline of the hub housing; the second clutch comprises a second pawl that couples or decouples the power transmission relationship between the second spline and the hub housing according to a rotational speed of the hub housing; and the second pawl is arranged on an outer peripheral side of the second spline.
The variable-speed hub according to claim 1, wherein the second spline comprises an external spline, and the second pawl is coupled with or decoupled from a plurality of spline parts of the external spline of the second spline.
The variable-speed hub according to claim 2, wherein the second pawl comprises a rotating shaft, and a drive arm connected to the rotating shaft and rotating around the rotating shaft, a distal end of the drive arm away from the rotating shaft being configured to couple with or decouple from the plurality of spline parts, the distal end being arranged at a position radially close to the plurality of spline parts, and the rotating shaft being arranged at a position radially away from the plurality of spline parts.
The variable-speed hub according to claim 3, wherein the distal end of the drive arm away from the rotating shaft has a first width, and a proximal end close to the rotating shaft has a second width, the first width being smaller than the second width, and an arc transition part being formed at the transition between the first width and the second width.
The variable-speed hub according to claim 4, wherein the plurality of spline parts comprises a matching groove configured to match with the distal end, and a driving surface and a circumferential outer arc surface that decouple the power transmission relationship between the second pawl and the second spline, the driving surface being a slope surface that inclines up to the circumferential outer arc surface.
The variable-speed hub according to claim 5, wherein when the second pawl overtakes the plurality of spline parts, the second pawl rises to the circumferential outer arc surface along the driving surface of the spline part located ahead in a rotation direction of the hub housing, and the arc transition part matches with the circumferential outer arc surface, allowing the distal end of the drive arm to deflect at a certain angle to be away from the circumferential outer arc surface; and the angle allows a retaining structure of a second clutch plate in the second clutch to match with a distal end of the second pawl, decoupling the power transmission relationship between the second pawl and the external spline of the second spline.
The variable-speed hub according to claim 2, wherein the external spline of the second spline comprises at least 12 or 14 spline parts.
The variable-speed hub according to claim 1, wherein the second clutch comprises the second clutch plate, a second centrifugal block, and the second pawl; the second centrifugal block is fixed to a second end cap of the hub housing via the rotating shaft; and the second end cap comprises a groove for accommodating the second pawl, and the groove comprises a shaft groove, and the rotating shaft of the second pawl is capable of rotating inside the shaft groove; when the rotational speed of the hub housing is higher than a second rotational speed, the second centrifugal block drives the second clutch plate to rotate in a direction opposite to the rotation direction of the hub housing, allowing the second clutch plate to rotate to a first position where the second clutch plate couples the power transmission relationship between the second pawl and the external spline of the second spline; and when the rotational speed of the hub housing is lower than the second rotational speed, the second centrifugal block drives the second clutch plate to rotate in the same direction as the rotation direction of the hub housing, allowing the second clutch plate to rotate to a second position where the second clutch plate decouples the power transmission relationship between the second pawl and the external spline of the second spline.
The variable-speed hub according to claim 1, wherein when the second pawl is coupled with the second spline, a bearing pressure on a matching surface is F=T/R1, R1 being a radius of the external spline of the second spline, and T being an input torque of a planetary gear set.
The variable-speed hub according to claim 1, further comprising: a third-level drive component, connected to the second-level drive component via a planetary gear set; the third-level drive component comprising a third clutch, the third clutch being fixed to the hub housing, rotating along with the hub housing, and being configured to drive a third spline of the hub housing; the third clutch comprising a third pawl for coupling or decoupling the power transmission relationship between the third spline and the hub housing according to the rotational speed of the hub; and the third pawl being arranged on an outer peripheral side of the third spline.

Description

Technical Field The present invention belongs to the field of riding vehicles, and in particular to the improvement of a variable-speed hub. Background In prior art, bicycles, electric bikes, and other vehicles can provide automatic speed changing functions that are achieved through the arrangement of an automatic variable-speed hub. A power input end of the automatic variable-speed hub is connected to a freewheel of a bicycle or a motor output shaft of an electric bike to provide power. According to the inputted rotational speed, the variable-speed hub is capable of automatically changing the gear ratio between the input and output ends, to automatically adjust the traveling speed of the bicycle or electric bike, achieving high-speed travel and low energy consumption effect. Requiring no manual operation and being convenient in riding, the variable-speed hub is widely praised. The function of the variable-speed hub is generally achieved through built-in first, second, or third-level power output devices. Typically, the first-level power output device is configured to directly drive a hub housing; the second-level power output device, after being sped up through a planetary gear set, is configured to drive the hub housing; and the third-level power output device, after being further sped up based on the second-level rotational speed through a planetary gear set, is configured to drive the hub housing. There are problems in two aspects in prior art. 1. The coupling or decoupling of the power transmission relationship between a clutch device and the hub housing is driven by the rotational force inputted from the power end. After stopping coasting, the user needs to pedal with low resistance to couple the clutch with the hub housing, so as to reach the gear corresponding to the rotational speed. Pedaling with low resistance brings the user a short and rapid sensation of "empty pedaling", resulting in a poor riding experience. 2. In prior art, being arranged inside the spline, a pawl of the clutch is coupled with the interior of the spline when the rotational speed reaches the corresponding gear. Due to the small internal radius of the spline, the corresponding force arm of the pawl is smaller, and the end surface where the pawl matches with the spline bears a greater torque, which can cause greater stress on the pawl itself, or result in a shaft of the pawl being jammed, leading to a failure in upshifting or downshifting. Additionally, the arrangement of pawl inside the spline leads to a more complex structure and assembly process of the clutch. Summary An objective of the present invention is to provide a variable-speed hub that avoids pedal skipping, reduces pawl damage, prevents jamming, and simplifying the structure. Specifically, the present invention provides a variable-speed hub, including: a hub housing;a first-level drive component, directly driving the hub housing via a first pawl; anda second-level drive component, connected to the first-level drive component via a planetary gear set. The second-level drive component includes a second clutch. The second clutch is fixed to the hub housing, rotates along with the hub housing, and is used for driving a second spline of the hub housing. The second clutch includes a second pawl that couples or decouples the power transmission relationship between the second spline and the hub housing according to a rotational speed of the hub housing. The second pawl is arranged on an outer peripheral side of the second spline. In a preferred example of the present invention, the second spline includes an external spline, and the second pawl is coupled with or decoupled from a plurality of spline parts of the external spline of the second spline. In a preferred example of the present invention, the first-level drive component includes a planet gear and a planet carrier of the planetary gear set, with the planet gear rotatably fixed on the planet carrier. The second-level drive component includes a gear ring of the planetary gear set, and the second spline is arranged on the gear ring to rotate along with the gear ring. In a preferred example of the present invention, the second pawl includes a rotating shaft, and a drive arm connected to the rotating shaft and rotating around the rotating shaft. A distal end of the drive arm away from the rotating shaft is configured to couple with or decouple from the plurality of spline parts. The distal end is arranged at a position radially close to the plurality of spline parts, and the rotating shaft is arranged at a position radially away from the plurality of spline parts. In a preferred example of the present invention, the distal end of the drive arm away from the rotating shaft has a first width, and a proximal end close to the rotating shaft has a second width. The first width is smaller than the second width, and an arc transition part is formed at the transition between the first width and the second width. In a preferred e