WO2022241935A1

WO2022241935A1 - Mid-drive motor transmission mechanism, electric-assist bicycle driving system, and electric-assist bicycle

Info

Publication number: WO2022241935A1
Application number: PCT/CN2021/106372
Authority: WO
Inventors: 李敏和; 张秋阳; 曾奇方
Original assignee: 广东高标电子科技有限公司
Priority date: 2021-05-20
Filing date: 2021-07-15
Publication date: 2022-11-24
Also published as: DE112021007683T5; CN113184105A

Abstract

A central motor transmission mechanism, an electric-assist bicycle driving system, and an electric-assist bicycle. The mid-drive motor transmission mechanism comprises a central shaft (1), an input gear (2), an output gear (3), a clutch (4), and a central shaft supporting bearing (5). The input gear (2) is provided to be engaged with a speed reducer output gear (200); the output gear (3) is provided to transmit power to a crankset; the clutch (4) is sleeved on the central shaft (1) and is transmittingly connected to the central shaft (1); the output gear (3) is sleeved on the clutch (4) and is transmittingly connected to the clutch (4); and the central shaft supporting bearing (5) and a stepped fitting (11) of the central shaft (1) are respectively located on either end of the output gear (3), so as to limit the output gear (3), thereby realizing the positioning of the input gear (2) and the output gear (3), ensuring accurate positioning, and reducing transmission noise.

Description

Central motor transmission mechanism, electric moped drive system and electric moped

This application claims the priority of a Chinese patent application with a filing date of May 20, 2021 and application number 202110552408.X, the entire contents of which are incorporated herein by reference.

technical field

The present application relates to the technical field of electric bicycles, for example, it relates to a mid-mounted motor transmission mechanism, a driving system of electric bicycles and electric bicycles.

Background technique

The electric moped can realize two driving modes: human-powered drive and electric power-assisted drive, and can provide corresponding electric power-assisted support in different proportions according to the strength of the rider's pedaling. The electric power assist of electric mopeds usually includes two forms. One is to use the hub motor to achieve electric power assist. The hub motor is to integrate the motor into the inside of the hub tube. After the power is turned on, the motor converts electrical energy into mechanical energy to drive the wheel to rotate; One is to use the mid-mounted motor to achieve electric power assistance. The mid-mounted motor needs to transmit the power output by the motor to the output shaft of the electric bicycle through the transmission mechanism, and then transmit the power to the crankshaft through the output shaft, and finally pass the chain to the crankshaft. The power is transmitted to the wheels to realize the rotation of the wheels.

As shown in Figure 1, the existing central motor transmission mechanism includes a central shaft 1', an input gear 2', an output gear 3' and a clutch 4', wherein the input gear 2' is transmitted to the central shaft 1' through the clutch 4'. connection, the output gear 3` is integrally formed with the center shaft 1`, and the reducer input gear 100` is driven and matched with the output end of the mid-mounted motor, and the power of the mid-mounted motor is transmitted to the The input gear 2` drives the center shaft 1` to rotate through the clutch 4` and drives the output gear 3` to rotate, and finally outputs the power to the tooth plate to realize the electric drive of the electric moped. In the process of transmitting power (torque and speed), the input gear 2` will generate radial force, tangential force and axial force, among which, the radial force and circumferential tangential force are mainly driven by the clutch `4 and the center shaft 1` The axial force is mainly borne by the stepped matching surface of the central shaft 1`, and these forces will be transmitted to the shaft section of the output gear 3`. The radial force and tangential force existing in the shaft section of the output gear 3` Forces and axial forces are borne by bearings arranged at both ends of it.

The design method of the above-mentioned central motor transmission mechanism has the following problems: 1) When the clutch 4` is a sprag clutch, the clutch 4` does not have a centering function, and the centering of the input gear 2` is mainly determined by the cylinder of the central shaft 1`. The mating surface works, but the relative movement between the input gear 2` and the central shaft 1` may easily cause wear on the cylindrical mating surface of the central shaft 1`, which further causes problems such as inaccurate positioning of the input gear 2` and large vibration and noise. 2) When the integrated clutch is selected for the clutch 4`, the size of the integrated clutch is much larger than that of the sprag clutch when the same torque is transmitted, and there is a possibility of interference with the input gear 100` of the reducer. To avoid the clutch 4 ′ interfering with the reducer input gear 100 ′, it is necessary to increase the length of the central shaft 1 ′, so that the size of the entire mechanism is relatively large, which cannot meet the requirements of the installation space.

Contents of the invention

The application provides a central motor transmission mechanism, which can realize the positioning of the transmission gear without increasing the overall size of the mechanism, ensure accurate positioning of the transmission gear, and reduce transmission noise.

The present application provides a driving system for an electric moped, which has a compact structure, a small overall size, and low power transmission noise by applying the above-mentioned central motor transmission mechanism.

The present application provides an electric moped, which has a compact structure, a small overall size, and low power transmission noise by applying the above-mentioned electric moped drive system.

In the first aspect, a central motor transmission mechanism is provided, including:

a central shaft, on which a stepped fitting is arranged;

The input gear is coaxially fixedly connected with the central shaft, and the input gear is configured to mesh with the output gear of the reducer;

a clutch, sleeved on the central shaft and connected with the central shaft;

an output gear, sleeved on the clutch and connected to the clutch in transmission, and the output gear is configured to transmit power to the crankshaft;

The central shaft support bearing, wherein, the central shaft support bearing and the stepped fitting are respectively located at both ends of the output gear, so as to limit the output gear.

In a second aspect, an electric bicycle drive system is provided, including a central motor, a speed reducer, and the above-mentioned central motor transmission mechanism.

In a third aspect, an electric bicycle is provided, including the electric bicycle driving system as described above.

Description of drawings

FIG. 1 is a schematic cross-sectional view of a central motor transmission mechanism in the related art;

Fig. 2 is a schematic structural diagram of a central motor transmission mechanism provided by an embodiment of the present application;

Fig. 3 is a cross-sectional view of the middle motor transmission mechanism provided by the embodiment of the present application;

Fig. 4 is an exploded schematic view of the middle motor transmission mechanism provided by the embodiment of the present application.

Reference signs:

100-reducer input gear; 200-reducer output gear;

1-center shaft; 11-ladder fittings;

2 - input gear;

3-output gear; 31-limiting groove;

4 - clutch;

5- Central shaft support bearing;

6- the first limit bearing;

7-circlip;

8 - Gasket;

9-Second limit bearing.

Detailed ways

In the description of this application, unless otherwise clearly specified and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated ; It can be a mechanical connection or other connections; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two elements or the interaction relationship between two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application in specific situations.

In this application, unless otherwise expressly specified and limited, a first feature being "on" or "under" a second feature may include direct contact between the first and second features, and may also include the first and second features Not in direct contact but through another characteristic contact between them. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. "Below", "beneath" and "under" the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

In the description of this embodiment, the terms "up", "down", "left", "right" and other orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operations. It is not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed, or operate in a particular orientation, and thus should not be construed as limiting the application. In addition, the terms "first" and "second" are only used to distinguish in description, and have no special meaning.

This embodiment provides a driving system for an electric bicycle, which includes a central motor, a speed reducer and a transmission mechanism for the central motor. Wherein, the speed reducer includes a speed reducer input gear 100 and a speed reducer output gear 200, the speed reducer input gear 100 is connected to the output end of the central motor, and the speed reducer output gear 200 is set to transmit power to the central motor transmission mechanism, and then The power is transmitted to the chain plate by the central motor transmission mechanism to realize the electric drive of the electric moped.

As shown in Figures 2-4, the central motor transmission mechanism provided by this embodiment includes a central shaft 1, an input gear 2, an output gear 3, a clutch 4 and a central shaft support bearing 5, wherein the input gear 2 is set to The output gear 200 of the reducer is meshed, and the output gear 3 is set to transmit the power to the tooth plate; the central shaft 1 is provided with a stepped fitting 11; the input gear 2 is fixedly connected to the central shaft 1 coaxially; the clutch 4 is set on the central shaft 1 and is connected to the central shaft 1; the output gear 3 is sleeved on the clutch 4 and is connected to the clutch 4; The step fit piece 11 is set to limit the output gear 3 . The central motor transmission mechanism fixes the input gear 2 on the central shaft 1, the output gear 3 is connected to the central shaft 1 through the clutch 4, and utilizes the stepped fitting 11 on the central shaft 1 and the central shaft support bearing 5 pairs The output gear 3 is limited, so that the positioning of the input gear 2 and the output gear 3 can be realized without increasing the size of the central shaft 1, ensuring accurate positioning and reducing transmission noise.

The driving system of the electric bicycle provided by the present application adopts the above-mentioned central motor transmission mechanism, which has a compact structure, a small size of the whole machine, and low power transmission noise.

In normal operation, the input gear 2 receives the power input from the output gear 200 of the reducer, the input gear 2 rotates and drives the clutch 4 to work, the clutch 4 further drives the output gear 3 to rotate, and the output gear 3 outputs power to the crankset through the gears matched with it . During the power transmission process of the output gear 3, an axial force will be generated, which can be borne by the stepped fitting 11 and the central shaft support bearing 5 to limit the output gear 3, ensure the accurate positioning of the output gear 3, and reduce the power pass noise.

Optionally, the input gear 2 is spaced from the stepped fitting 11 to accommodate the input gear 100 of the reducer, so as to make full use of the layout space of the center shaft 1 and reduce the size of the whole machine.

Exemplarily, the clutch 4 can be a sprag clutch, and the clutch 4 is a one-way clutch.

Optionally, the central motor transmission mechanism also includes a first limit bearing 6 and a second limit bearing 9, the first limit bearing 6 and the second limit bearing 9 are respectively arranged at both ends of the clutch 4, and are arranged as Carry out axial limit to clutch 4. During the power transmission process of the output gear 3, radial force and tangential force will also be generated, wherein the radial force and tangential force are mainly borne by the first limit bearing 6 and the second limit bearing 9, and the clutch 4 does not need to bear , to avoid the inclination of the wedges of the clutch 4 being inconsistent in force, resulting in the eccentricity of the center shaft 1 that cooperates with the clutch 4, resulting in the clutch 4 not working smoothly or not working. In addition, the axial force generated by the output gear 3 can be transmitted to the input gear 2 through the stepped fitting 11 instead of being borne by the first limit bearing 6 and the second limit bearing 9, reducing the size of the first limit bearing 6 and the second limit bearing. The working force of limit bearing 9 improves its service life.

Optionally, both the first limit bearing 6 and the second limit bearing 9 are located between the output gear 3 and the central shaft 1 . That is, the first limit bearing 6 and the second limit bearing 9 are located inside the output gear 3 and outside the center shaft 1, and bearings with a smaller outer diameter can be selected to meet the space layout requirements.

In this embodiment, the inside of the output gear 3 is a stepped hole, and the aperture of the shaft section where the first limit bearing 6 and the clutch 4 are assembled is larger than the aperture of the shaft section where the second limit bearing 9 is assembled. Limiting the position can ensure the structural strength of the output gear 3 while reducing the diameter of the output gear 3 .

Exemplarily, the first position-limiting bearing 6 and the second position-limiting bearing 9 may be of different types, or may be of the same type. In this embodiment, the first limiting bearing 6 adjacent to the stepped fitting 11 is a ball bearing, and the second limiting bearing 9 is a needle bearing.

Optionally, in order to limit the axial direction of the clutch 4 , the central motor transmission mechanism further includes a clip spring 7 which is arranged between the first limit bearing 6 adjacent to the stepped fitting 11 and the clutch 4 .

Optionally, a limiting groove 31 is provided on the inner wall of the output gear 3, and the circlip 7 is accommodated in the limiting groove 31, so as to ensure that the relative position of the clutch 4 and the output gear 3 remains unchanged and ensure the power transmission effect.

Optionally, the central motor transmission mechanism further includes a gasket 8 which is arranged between the central shaft support bearing 5 and the output gear 3 . By arranging the gasket 8 between the central shaft support bearing 5 and the output gear 3, the axial limit of the second limit bearing 9 and the output gear 3 can be performed, and the transmission stability can be improved. In addition, it can also reduce the wear of the centering shaft support bearing 5 and prolong the service life of parts.

Optionally, the input gear 2 and the central shaft 1 are integrally formed, which not only can ensure the coaxial transmission of the input gear 2 and the central shaft 1, but also ensure accurate positioning of the input gear 2 and ensure the transmission effect.

This embodiment also provides an electric bicycle, which includes the above-mentioned electric bicycle driving system. By applying the above electric bicycle driving system, the electric bicycle has a compact structure and a smaller size.

Claims

A central motor transmission mechanism, comprising:

A central axis (1), on which a stepped fitting (11) is arranged;

The input gear (2) is coaxially and fixedly connected with the central shaft (1), and the input gear (2) is configured to mesh with the reducer output gear (200);

a clutch (4), sleeved on the central shaft (1) and connected with the central shaft (1);

The output gear (3) is sleeved on the clutch (4) and is in transmission connection with the clutch (4), and the output gear (3) is configured to transmit power to the chainring;

A central shaft support bearing (5), wherein the central shaft support bearing (5) and the stepped fitting (11) are respectively located at both ends of the output gear (3) to limit the output gear (3) bit.
The central motor transmission mechanism according to claim 1, further comprising a gasket (8), the gasket (8) being arranged between the central shaft support bearing (5) and the output gear (3).
The middle motor transmission mechanism according to claim 1, further comprising a first limit bearing (6) and a second limit bearing (9), the first limit bearing (6) and the second limit bearing Bearings (9) are respectively arranged at both ends of the clutch (4).
The central motor transmission mechanism according to claim 3, wherein the first limit bearing (6) and the second limit bearing (9) are respectively located on the output gear (3) and the central shaft (1) Between.
The middle-mounted motor transmission mechanism according to claim 3, further comprising a snap ring (7), and the snap ring (7) is arranged between the first limit bearing (6) and the clutch (4).
The central motor transmission mechanism according to claim 5, wherein a limiting groove (31) is opened on the inner wall of the output gear (3), and the retaining spring (7) is accommodated in the limiting groove (31 )Inside.
The central motor transmission mechanism according to any one of claims 1-6, wherein the input gear (2) and the central shaft (1) are integrally formed.
The central motor transmission mechanism according to claim 7, wherein a space is provided between the input gear (2) and the stepped fitting (11), and the space is set to accommodate the reducer input gear (100 ).
A driving system for an electric bicycle, comprising a central motor, a speed reducer, and the central motor transmission mechanism according to any one of claims 1-8.
An electric bicycle, comprising the driving system of the electric bicycle according to claim 9.