Drive system and method for electric bicycle equipped with a gear shifter
The integration of an electronic control unit with an acceleration sensor and GPS module in the electric bicycle drive system enables precise and timely gear shifts, improving the riding experience by adapting to various conditions.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- BROSE ANTRIEBSTECHN GMBH & CO KGAA BERLIN
- Filing Date
- 2024-06-10
- Publication Date
- 2026-06-25
AI Technical Summary
Existing electric bicycle drive systems lack a control mechanism that can accurately and automatically adjust gear shifts based on multiple parameters, leading to suboptimal riding experiences.
A drive system with an electronic control unit that integrates an acceleration sensor and GPS module to determine gear shifts based on torque, pedal rotation speed, and additional parameters like acceleration and geographical location, enabling precise and timely gear changes.
Enhances the riding experience by allowing for quicker and more situation-appropriate gear changes, providing a natural and comfortable driving feel.
Smart Images
Figure 2026520971000001_ABST
Abstract
Description
Technical Field
[0001] The proposed solution relates to the drive system for an electric bicycle described in the preamble of claim 1 and the method described in claim 7.
Background Art
[0002] In an electric bicycle, it is known to provide a drive train having an electric drive motor and a crank element that act on a bottom bracket shaft to apply a driving force for driving the wheels of the electric bicycle. In order to change the gear ratio between the drive train and the driven wheels, a transmission capable of performing a gear shift operation is usually provided. Usually, the gear shift operation is performed by the driver of the electric bicycle as needed. Alternatively, an electronic control device for automatically performing the gear shift operation is provided. The control device can perform the gear shift operation based on the driver's torque and / or pedal rotation speed.
Summary of the Invention
Means for Solving the Problems
[0003] In view of this background, the proposed solution aims to provide a drive system that includes a transmission and an electronic control device for controlling the transmission, enabling a better riding sensation.
[0004] According to a first aspect of the proposed solution, this object is achieved by the drive system for an electric bicycle described in claim 1. The drive system has a drive train including at least one electric drive motor and at least one crank element, each for applying a driving force for driving the wheels of the electric bicycle. At least one electric drive motor can provide a motor driving force, and at least one crank element can provide a driver driving force. Each driving force can be applied to the bottom bracket shaft of the drive system for driving the wheels of the electric bicycle. The driving forces are combined into a total driving force at the bottom bracket shaft, which is transmitted to the wheels by a power transmission element such as a chain.
[0005] Furthermore, the drive system has a transmission for performing gear changes that alter the gear ratio between the drivetrain and the driven wheels. A high gear ratio allows for relatively large wheel movements using high driving force. At the same number of pedal rotations, a low gear ratio achieves only slight wheel movements in the same amount of time, but requires less driving force for those slight movements.
[0006] The drive system also includes an electronic control unit for controlling the transmission, which is configured to determine whether or not to perform a gear shift based on the torque and / or pedal rotation speed input by the electric bicycle rider through at least one crank element. This makes it possible to automate the gear shifting operation, allowing the rider to concentrate more on driving.
[0007] The proposed solution is based on the idea of improving the control system, not only by controlling the transmission in response to driver input in the form of torque and / or pedal rotation speed, in order to achieve a good and natural driving feel. Therefore, the control system is configured to determine the execution of a gear shift operation based on at least one other parameter. If at least one other parameter can be used in addition to, or instead of, pedal rotation speed and torque, the electronic control system can more accurately determine how to control the transmission.
[0008] In one embodiment, at least one other parameter is independent of the operating parameters of the drive system. These operating parameters may include parameters that must be defined anyway during a given operation of the drive system in an electric bicycle in order to ensure proper wheel operation and drive. These include, for example, torque and pedal rotation speed. In this regard, at least one parameter can be said to be independent of the operating parameters of the drive system if, for example, it can be measured independently of the drive system during the operation of the electric bicycle.
[0009] In one embodiment, the drive system includes an acceleration sensor, which can provide at least one other parameter as the acceleration of the electric bicycle. The acceleration sensor may include, for example, an inertial measuring unit (IMU).
[0010] Acceleration is an example of a parameter independent of the drive system's operating parameters. It allows the electronic control unit to more accurately assess the riding conditions in which the electric bicycle is positioned, thereby enabling the initiation of gear changes that are more precisely suited to those conditions. For example, during uphill and downhill riding, changes in acceleration can make it easier to distinguish between uphill and downhill riding conditions. Compared to controlling the gear shift based solely on torque and / or pedal rotation speed, using acceleration additionally or as an alternative allows for quicker and more situation-appropriate gear changes, which contributes to a better and more natural riding feel.
[0011] In one embodiment, the drive system includes a GPS module, which can provide at least one additional parameter as the geographical location of the electric bicycle. The GPS module allows for further optimization of the gear shift control compared to using acceleration. For example, while riding uphill and downhill along a route, the geographical location can predict the uphill and downhill slopes ahead, enabling the control unit to perform gear shifting operations more quickly and accurately in response to riding conditions. The control unit may be configured and designed to detect and analyze uphill and downhill slopes in advance.
[0012] In one embodiment, the decision to perform a gear shift operation includes determining the gear shift timing. The gear shift timing allows the control device to instruct the transmission at what point in time the gear shift operation should be performed.
[0013] The proposed solution also relates to electric bicycles equipped with this drive system.
[0014] According to a second aspect of the proposed solution, the objective is achieved by a method of operating a drive system for an electric bicycle. This method includes the following steps: To determine at least one parameter independent of the operating parameters of the drive system, Based on the torque input by the electric bicycle driver and / or the pedal rotation speed input by the driver, and based on at least one parameter, it is determined whether or not a gear shift operation should be performed to change the gear ratio between the electric bicycle's drivetrain and the wheels of the electric bicycle being driven, and Perform a gear shift operation.
[0015] The proposed solution also relates to a computer program product for an electronic control device that controls a gearbox for changing the gear ratio between the drivetrain and the driven wheels of an electric bicycle, wherein the computer program product includes instructions that cause at least one processor of the control device to perform the above method when the instructions are executed.
[0016] The advantages and features described in relation to the first aspect of the proposed solution can also be applied to the method according to the second aspect. [Brief explanation of the drawing]
[0017] The attached drawings illustrate exemplary embodiments of the proposed solution. [Figure 1] An electric bicycle equipped with an embodiment of the proposed drive system is shown. [Figure 2] A schematic diagram of the control device configuration is shown. [Modes for carrying out the invention]
[0018] Figure 1 shows, as an example, an electric bicycle 1 having a frame 10, to which a front wheel 11 and a rear wheel 12 are rotatably supported. The rear wheel 12 is drivable with the assistance of an electric motor via a drive system having a drivetrain A. For this purpose, the drivetrain A has at least one electric drive motor in the form of an electric motor M. The drive torque generated by the electric motor M is drivable to the rear wheel 12 via a power transmission element 13 such as a chain or belt (in addition to the drive torque applied manually, optionally via the bottom bracket shaft T). In this way, not only can a first drive torque applied by the driver of the electric bicycle 1 via pedals connected to the bottom bracket shaft T be transmitted to the rear wheel 12, but rather, the rear wheel 12 can also be driven by a second drive torque generated by the electric motor M. The two drive torques can be provided as a total torque via the bottom bracket shaft T.
[0019] A transmission 14 is provided between the drive train A and the driven rear wheel 12. The transmission 14 can be used to perform a shifting operation that changes the gear ratio between the drive train A and the driven wheel 12. The shifting operation can be performed, for example, by a derailleur or other shifting mechanism of the transmission 14 at the hub of the rear wheel 12, which enables switching between different chainrings for the chain.
[0020] An electronic control unit SE is provided to control the transmission 14. The control unit SE is configured to determine whether or not to perform a shifting operation. For this purpose, the control unit SE can automatically execute a shifting operation via the transmission 14. To determine the shifting timing as accurately as possible, the control unit SE is coupled with an acceleration sensor 21 and a GPS module 20. The acceleration sensor 21 and the GPS module 20 can be arranged at any position of the electric bicycle 1. The illustrated positions are merely exemplary.
[0021] FIG. 2 shows an exemplary configuration of the control unit SE for controlling the transmission 14. First, the control unit SE is coupled with a rotation speed unit 22 and a torque unit 23. These provide the pedal rotation speed and torque. The torque and pedal rotation speed are specified by the driver of the electric bicycle 1 at the crank element K. Based on the pedal rotation speed and / or torque, the control unit SE can determine whether or not to perform a shifting operation. Further, the control unit SE can make a determination as to whether or not to perform a shifting operation based on the acceleration of the electric bicycle 1 and the geographical position of the electric bicycle 1 provided via the acceleration sensor 21 and the GPS module 20. This improves the determination and enables a better riding feeling.
Explanation of Signs
[0022] 1 Electric bicycle 10 Frame 11 Front wheel 12 Rear wheel 13 Power transmission element 14 Transmission 20 GPS Module 21 Acceleration Sensor 22 Revolution Unit 23 Torque Unit A Drive Train K Crank Element M Electric Motor SE Electronic Control Unit T Bottom Bracket Shaft
Claims
1. A drive system for an electric bicycle (1), A drivetrain (A) comprising at least one electric drive motor (E) and at least one crank element (K), each configured to apply driving force to drive the wheels (12) of the electric bicycle (1), A transmission (14) for performing a gear change operation to change the gear ratio between the drivetrain (A) and the driven wheels (12), An electronic control device (SE) for controlling the gear shift (14) is configured to determine whether or not to perform a gear shift operation based on at least one of the torque and pedal rotation speed input by the driver of the electric bicycle (1) to the at least one crank element (K), It has, The drive system is characterized in that the control device (SE) is configured to determine the execution of the gear shift operation based on at least one other parameter.
2. The drive system according to claim 1, characterized in that the at least one other parameter is independent of the operating parameters of the drive system.
3. The drive system according to claim 1 or 2, characterized in that it comprises an acceleration sensor (21), and the acceleration sensor (21) is capable of providing the at least one other parameter as the acceleration of the electric bicycle (1).
4. The drive system according to any one of claims 1 to 3, comprising a GPS module (20), wherein the GPS module (20) is capable of providing the at least one other parameter as the geographical location of the electric bicycle (1).
5. The drive system according to any one of the preceding claims, characterized in that determining the execution of the gear shift operation includes determining the gear shift timing.
6. An electric bicycle (1) having a drive system according to any one of claims 1 to 5.
7. A method for operating a drive system for an electric bicycle (1), To determine at least one parameter independent of the operating parameters of the drive system, Based on at least one of the torque input by the driver of the electric bicycle (1) and the pedal rotation speed input by the driver, and based on at least one parameter, it is determined whether or not to perform a gear shift operation to change the gear ratio between the drivetrain (A) of the electric bicycle (1) and the driven wheel of the electric bicycle (1), and A method including performing the aforementioned gear shift operation.
8. A computer program product for an electronic control device (SE) for controlling a gear shift (14) for changing the gear ratio between a drivetrain (A) and a driven wheel of an electric bicycle (1), the computer program product comprising an instruction that, when an instruction is executed, causes at least one processor of the control device (SE) to execute the method according to claim 7.