Methods for steering a bicycle

Abstract

The invention relates to a method for steering a bicycle. The method comprises a step (22) of changing the steering characteristics of the bicycle's steering system when the bicycle is being pushed. The invention further relates to a steering adjustment system (12) for a bicycle. The steering adjustment system (12) is configured to change the steering characteristics of the bicycle's steering system when the bicycle is being pushed.

Description

Technical field

[0001] The present invention relates to a method for steering a bicycle. Furthermore, the invention relates to a steering adjustment system for a bicycle. State of the art

[0002] Bicycles in various designs are known from the prior art. Traditionally, a bicycle has steering for changing direction and a drivetrain for providing propulsion. The steering is operated by a user to change the bicycle's direction. The drivetrain is operated by the user, for example via pedals, to propel and move the bicycle. In certain situations, however, it is desirable to move the bicycle by pushing it, without significantly engaging the drivetrain. For example, the user might push the bicycle from a parking space onto a roadway before mounting and riding off. Bicycles are also frequently pushed when going down steep inclines.

[0003] The user can grip the bicycle at various points to push it, such as the frame, handlebars, or saddle. This can be uncomfortable, as the frame and saddle are not ergonomically designed as grips. Pushing the bicycle by the handlebars can also be awkward, as the user's sideways position can lead to unwanted steering movements. For example, the rider might only be able to hold one handlebar grip with one hand, causing the handlebars to twist easily while pushing. The user can also grip the handlebars in the middle with one hand. This can be uncomfortable because the user has to extend their arm far and exert considerable force to control any steering movements. Gripping the frame or saddle can also restrict control over the bicycle's steering.For example, the handlebars, and therefore the front wheel, can simply swivel freely away when subjected to impacts. Description of the invention

[0004] The object of the present invention is to improve the comfort of a user when pushing a bicycle. This object is achieved by the respective subject matter of the dependent claims.

[0005] A first aspect of the invention relates to a method for steering a bicycle. The bicycle can be, for example, a conventional bicycle, a pedelec, or a cargo bike. A conventional bicycle can, for example, be free of a drive motor and have only two wheels. However, the bicycle can also have, for example, three, four, or more wheels. The steering system can, for example, include handlebars that pivot a front wheel relative to the bicycle frame to change the bicycle's direction of travel. For example, the handlebars can be attached to a steering tube, and the steering tube can be mounted to the frame via a headset. Alternatively or additionally, the handlebars and a fork can each be pivotably mounted to the frame. The steering system can also include steering actuators between the handlebars and the frame, as well as between the fork and the frame.This allows for the implementation of a steer-by-wire steering system for bicycles. The steering actuators can be configured to detect and modify steering angles. These actuators can be controlled to couple the steering angle of the handlebars with that of the fork. During operation, the ratio between handlebar and fork movement can be adjusted. The steering angles of the handlebars and fork need not be identical during operation; they can differ. Alternatively, or additionally, the handlebars and fork can move in at least the same direction.

[0006] Pushing a bicycle can be a state in which the user moves the bicycle without significantly operating the drivetrain. For example, while pushing, the user can walk alongside the bicycle and push it with one hand on the handlebars and one hand on the saddle, without touching the pedals of the drivetrain.

[0007] The procedure includes a step of modifying the steering characteristics of a bicycle's steering system while the bicycle is being pushed. The steering characteristics can, for example, describe the bicycle's response and steering action to a force or torque applied to the handlebars. By modifying the steering characteristics, a property of the steering system can be altered, for instance, to make it easier, more difficult, or at least partially limit the pivoting of the handlebars relative to the frame. The steering characteristics influence the steering's response to user inputs and actions, the bicycle's riding condition, and other external forces acting on the bicycle. For example, the steering characteristics can include steering resistance, steering angle, steering return force, and, alternatively or additionally, steering damping.Depending on the situation, it may be desirable to adjust the steering characteristics, making it more difficult or easier to turn. Changing the steering characteristics can stabilize the bicycle, allowing the user to concentrate less on steering while pushing. It can also improve the bicycle's maneuverability, making it easier for the user to maneuver the bike in tight spaces.

[0008] Changing the steering characteristics can be achieved, for example, by an actuator. The actuator can be, for instance, an electromechanical actuator, an electric actuator, an electromagnetic actuator, a pneumatic actuator, and alternatively or additionally a hydraulic actuator. When pushing the bicycle, the actuator can be used to facilitate, hinder, or limit steering movements relative to the frame.

[0009] Changing the steering characteristics can occur automatically, for example, when the bicycle is being pushed. The steering characteristics can change in response to a detected pushing motion. Alternatively or additionally, the steering characteristics can be changed manually. For example, the change can be activated by actuating a control element. As an example, the user can change the steering characteristics by flipping a lever, preferably near a handlebar grip, when the bicycle is being pushed or about to be pushed. Alternatively or additionally, the steering characteristics can change with a time delay after a ride has ended. The user can also activate a push mode, which then automatically changes the steering characteristics, as described below.

[0010] The method described above can reduce or eliminate unwanted steering movements while pushing the bicycle. As a result, pushing the bicycle becomes more comfortable. Furthermore, it improves control and maneuverability. This, in particular, enhances comfort, control, and safety when pushing the bicycle with just one hand.

[0011] In a further embodiment of the method, the method can include a step for detecting when the bicycle is being pushed. The steering characteristics can then be changed when the bicycle is being pushed. Pushing typically occurs at low speeds, for example, corresponding to the user's walking pace. Furthermore, the user does not transmit any or any significant torque to the bicycle's drivetrain while pushing. Additionally, there are no significant supporting forces on the saddle, steering, or, for example, the pedals of the drivetrain while pushing, since the user is neither sitting nor standing on the bicycle. These and other factors can be used to detect the pushing action, for example, by means of appropriate sensors on the bicycle.For example, a low speed of movement of the bicycle without any torque being applied to the drivetrain can be detected as pushing. Pushing can be detected, for instance, by a sensor integrated into the bicycle. The steering characteristics can then be adjusted in response to this detection. This allows the steering characteristics to change automatically without user intervention, which can improve comfort. Furthermore, the automatic adjustment of the steering characteristics while pushing can be deactivated by the user, for example, by disabling the detection, the actuator, or by disabling the steering characteristics change altogether.

[0012] In another embodiment of the method, the bicycle can be designed as a pedelec. Pushing the bicycle can be detected if the pedelec's push assist function is activated. Pedelecs have an auxiliary motor that supports the user while riding and provides additional propulsion. Furthermore, the auxiliary motor can provide push assistance by supplying propulsion that reduces the force the user has to exert to push the bicycle. For example, a small amount of power assistance can be provided to the user even without pedaling. Additionally, the steering characteristics can be modified when the push assist function is activated. The push assist function can be activated automatically or manually. Furthermore, activating the push assist function can be used to detect when pushing is taking place or is imminent.

[0013] In a further embodiment of the method, the steering characteristics can be changed back to an initial setting when a predetermined bicycle usage state is present. This prevents the user from being confronted with a changed steering characteristic in riding situations where this is unexpected or undesirable. For example, the steering characteristics can be changed back to the initial setting when the user wants to start riding the bicycle.

[0014] In general, a bicycle usage state can be any condition of the bicycle corresponding to its current use. This usage state can include parameters such as speed, acceleration, torque applied to the drivetrain by the user, steering angle, rate of change of steering angle, cadence, and other characteristics. The usage state can directly or indirectly influence the steering characteristics. For example, during normal riding, speed, due to the inertia of the wheels, affects steering resistance, which directly impacts the steering characteristics. Another example is that the bicycle may be designed to adjust adjustable properties, such as spring stiffness, in response to the usage state, which can indirectly influence the chassis geometry and thus the steering characteristics.

[0015] The predetermined bicycle usage state can be one that does not correspond to pushing. Alternatively or additionally, the predetermined bicycle usage state can be one in which the bicycle is pushed in a specific way, for example, maneuvering in confined spaces. Individual predetermined bicycle usage states will be discussed later. The initial characteristic can be a steering characteristic that existed before the steering characteristic was changed. For example, the steering characteristic for normal cycling can be, alternatively or additionally, a steering characteristic for a standstill.

[0016] The steering characteristics can revert to their initial state, for example, when pushing is no longer detected as a cycling mode. Alternatively or additionally, the steering characteristics can revert to their initial state in response to normal riding. Alternatively or additionally, the steering characteristics can revert to their initial state in response to the bicycle coming to a standstill. The steering characteristics can automatically revert to their initial state after the bicycle comes to a standstill, for example, after a predetermined period of time has elapsed following a stop while pushing. A stop can be detected, for example, based on the riding speed. A stop can be detected, for instance, if the riding speed does not exceed a threshold for at least a certain duration.The threshold value can be zero, for example, or slightly greater than zero. Alternatively or additionally, the steering characteristic can revert to its initial characteristic in response to the actuation of a control element.

[0017] In another embodiment of the method, the predetermined bicycle usage state can be present when a steering input parameter exceeds a threshold value. This steering input parameter can include steering force, steering torque, steering angle change rate, steering acceleration, and, alternatively or additionally, steering jerk. For example, the predetermined bicycle usage state can be present when the user applies sufficiently strong steering input. Strong steering input can, for instance, indicate that the user intends to override the altered steering characteristics and steer against them. Therefore, the original steering characteristics are restored when, for example, a steering input parameter exceeds a predetermined threshold value.For example, the predetermined bicycle usage state may be present when steering occurs at a steering angle change rate above a predefined threshold. Such rapid steering can occur, for instance, when the user has finished pushing and pivots the handlebars to more easily mount the bicycle.

[0018] In another embodiment of the method, the predetermined bicycle usage state can be present when a brake application parameter exceeds a threshold value. The brake application can be the actuation of a braking system by the user. The brake application parameter can include a brake application force, a brake application distance, and alternatively or additionally, a brake application speed. For example, the predetermined bicycle usage state can be present when a brake is applied at all, i.e., when the brake application distance is greater than zero. A brake application can, for instance, indicate that the user intends to stop pushing the bicycle. Alternatively, by setting the brake application distance threshold to a value greater than zero, slight braking can be tolerated without changing the steering characteristics back to their initial state.For example, it may happen that the bicycle is pushed downhill and occasional braking interventions are necessary to reduce its speed to the user's walking pace; in such a case, a change in the steering characteristics may be undesirable. Alternatively or additionally, braking with a high braking speed, or alternatively or additionally with a high braking force, may indicate that pushing has ended. Accordingly, the original characteristics are restored when the brakes are applied. This can occur alternatively or additionally to the restoration of the original characteristics due to steering input.

[0019] In another embodiment of the method, changing the steering characteristics can involve adjusting the steering resistance of the bicycle. The steering resistance can be a measure of the force required to pivot the handlebars relative to the frame. The steering resistance can be greater when pushing than when riding, thus stabilizing the bicycle while being pushed. For example, this makes it less likely that the rider will steer unintentionally if they push unevenly against the handlebars. Alternatively or additionally, the steering resistance can be lower when pushing than when riding, thus simplifying the maneuvering of the bicycle while being pushed.

[0020] In another embodiment of the method, modifying the steering characteristics can include limiting the maximum steering angle of the bicycle. The steering angle can be the angle of the handlebars and, alternatively or additionally, the wheel relative to the frame. The maximum steering angle can be a maximum value in one steering direction, or alternatively or additionally in both steering directions. For example, in a normal state, the steering angle might be limited simply by the front wheel contacting the frame. The maximum steering angle could, for example, be limited by an actuator. Alternatively or additionally, a mechanical locking mechanism can be used to limit the maximum steering angle. For example, the steering can be locked in a straight-ahead position. In this case, no or virtually no steering movement is possible.For example, when limiting the maximum steering angle, a stop can be placed in one of the steering's pivot paths.

[0021] The maximum steering angle when pushing the bike can be smaller than the maximum steering angle when riding. This provides additional stability while pushing, as unexpectedly large steering angles are avoided, thus improving comfort. Alternatively, the maximum steering angle when pushing the bike can be larger than the maximum steering angle when riding, thereby improving maneuverability.

[0022] In another embodiment of the method, the steering can be locked when the bicycle is stationary by limiting the maximum steering angle in a predetermined position, for example, in a straight-ahead position or at maximum steering deflection. This provides theft protection.

[0023] In a further embodiment of the method, changing the steering characteristics can involve adjusting a restoring force of a steering return mechanism. The restoring force can be a force that pushes the steering towards a straight-ahead position. The straight-ahead position can be a steering position in which the bicycle would travel straight ahead in an upright orientation. The restoring force can be greater when pushing the bicycle than when riding. The return mechanism can be a device that provides the restoring force. For example, the return mechanism can include an elastic component that couples the frame to the handlebars. Alternatively or additionally, the return mechanism can include an actuator that couples the frame to the steering.

[0024] In another embodiment of the method, the return device can include a return spring. The return spring can, for example, be connected to the frame at one end and eccentrically to the steering rod or handlebar at the other. The return spring can, for example, be designed as a coil spring. By adjusting the return force, a return spring force can be set as a function of the steering angle. For example, the preload of the return spring in a neutral steering position can be changed. The return spring force can be the force generated by the return device that forces the steering to the straight-ahead position. For example, the relationship of the return spring force to the steering angle can be changed. For example, the return spring force can increase linearly with increasing steering angle.Due to the change in steering angle, the return spring force can increase non-linearly, for example progressively, depending on the steering angle. For instance, at large steering angles, the gradient of the return spring force with respect to the steering angle may be greater than at small steering angles.

[0025] In another embodiment of the method, changing the steering characteristics can involve adjusting steering damping. Steering damping can be a measure of steering resistance that is dependent on the steering speed. This resistance can, for example, counteract changes in the steering angle. The damping can be set higher when pushing than when riding. This counteracts sudden, strong steering movements, for example, if the user or the bicycle has slipped. As a result, the bicycle is stabilized when being pushed. Adjusting the damping can involve modifying the viscosity of an electrorheological fluid using an electrical voltage. Alternatively or additionally, adjusting the damping can involve modifying the viscosity of a magnetorheological fluid using a magnetic field.Alternatively or additionally, adjusting the damping can involve adapting a throttle cross-section in a hydraulic damping component.

[0026] A second aspect of the invention relates to a steering adjustment system for a bicycle. The steering adjustment system can, for example, be configured to perform the method according to the first aspect. The respective advantages and further features can be found in the description of the first aspect, wherein embodiments of the first aspect also constitute embodiments of the second aspect and vice versa. The steering adjustment system is configured to change the steering characteristics of the bicycle's steering when the bicycle is being pushed.

[0027] In a further embodiment of the method, the steering adjustment system can also include a detection device configured to recognize when the bicycle is being pushed. The detection device can, for example, be integrated into a control unit provided on the bicycle. The detection device can include sensors configured to detect parameters relevant for detecting the pushing motion. For example, a speed sensor and a torque sensor can be provided in the drivetrain to detect a low speed of the bicycle without any torque being applied to the drivetrain and to recognize this as pushing. Alternatively or additionally, a cadence sensor can be provided in the drivetrain to detect a low speed of the bicycle without any torque being applied to the drivetrain and to recognize this as pushing.For example, a cadence less than or equal to a threshold value, such as zero, and a riding speed within a predefined range can be detected as pushing. Alternatively or additionally, further sensors in the drivetrain or on the bicycle can be used to detect pushing. Using multiple sensors, such as a speed sensor and a cadence sensor, allows for a more plausible correlation of the detection results and thus improved accuracy.

[0028] Another aspect concerns a bicycle. The bicycle may, for example, be designed to be operated using the method described in the first aspect. The bicycle may have a steering system whose characteristics can be modified using this method. The bicycle may have a steering adjustment system as described in the second aspect. The respective advantages and further features can be found in the descriptions of the first and second aspects, respectively, whereby embodiments of the first and second aspects also constitute embodiments of the further aspect, and vice versa. Brief description of the characters Fig. Figure 1 is a schematic representation of a bicycle. Fig. Figure 2 is a flowchart of a procedure for controlling the bicycle. Detailed description of embodiments

[0029] Fig. Figure 1 schematically shows a bicycle according to one embodiment in a top view. The bicycle is a pedelec. The bicycle has a frame 11, a front wheel 13, a rear wheel 15, a steering system with handlebars 10, and pedals 16. In an alternative embodiment, the bicycle has more than one front wheel 13 and, alternatively or additionally, more than one rear wheel 15. The rear wheel 15 is driven by a user via the pedals 16 to propel the bicycle in a certain direction. With the handlebars 10 in a straight position, the direction of travel is upwards. Fig. 1. The bicycle also has an electric auxiliary motor (not shown) that assists the user in driving the rear wheel 15. Furthermore, the electric auxiliary motor is designed to provide a driving force without the pedals 16 being operated when the bicycle is being pushed with the push assist activated.

[0030] The front wheel 13 is attached to the frame 11 via a fork (not shown) and can rotate about a transverse axis of the fork to roll on a surface. The handlebar 10 is fixed to the fork. By steering the bicycle, the front wheel can be rotated about an axis in the vertical direction, i.e., out of the plane of the image.

[0031] The handlebar 10, together with the front wheel 13, can be pivoted about a steering axis relative to the frame. This steering axis is perpendicular to the rotation axis of the front wheel 13 and essentially vertical. Thus, pivoting the handlebar 10 about the steering axis causes the front wheel 13 to pivot relative to the frame 11, thereby changing the direction of travel of the bicycle. In this case, the steering mechanism includes a return spring that forces the handlebar 10, and consequently the front wheel 13, into the straight-ahead position.

[0032] The bicycle also features a steering adjustment system 12, which is arranged on the bicycle's headset. The steering adjustment system 12 is designed to modify the steering characteristics. In this case, the steering adjustment system 12 includes an electrically actuated actuator designed to adjust the steering resistance. The steering adjustment system 12 also includes an electrically adjustable stop designed to be positioned on either side of the handlebar's pivot path 10 in order to limit the maximum steering angle of the handlebar 10 on either side. The steering adjustment system 12 is also designed to adjust the return spring force. The steering adjustment system 12 can be deactivated by the user via an operating button located near the handlebar.

[0033] The bicycle also has a detection device 14. The detection device 14 is designed to detect when the bicycle is being pushed. In this case, the detection device 14 is connected to a speed sensor on the rear wheel 15 and to a torque sensor, or in an alternative embodiment, a cadence sensor, on the pedals 16. When the detection device 14 detects that the bicycle is being pushed, the steering characteristics can be automatically changed by the steering adjustment system 12.

[0034] Fig. Figure 2 shows a flowchart of a procedure for controlling the bicycle.

[0035] In its initial state, the bicycle's steering exhibits a defined initial characteristic. In this case, the initial characteristic is a steering characteristic for normal riding.

[0036] In step 20, pushing is detected. Specifically, in step 20, pushing is detected when the rotational speed of the rear wheel 15 corresponds essentially to a human walking speed and simultaneously a torque close to zero or a cadence close to zero is applied to the pedals 16. Furthermore, if a torque sensor is provided, the time elapsed since the last time the torque applied to the pedals 16 for propelling the bicycle exceeded a threshold value must be greater than a threshold value. Additionally, if a cadence sensor is provided, the time elapsed since the last time the cadence applied to the pedals 16 for propelling the bicycle exceeded a threshold value must be greater than a threshold value. Pushing is also detected when the bicycle's walk assist function is activated.

[0037] In step 22, in response to the detection in step 20, a steering characteristic is modified. Specifically, in step 22, the steering resistance is increased, the maximum steering angle is limited, and the return spring force is increased.

[0038] Step 24 detects when a predetermined bicycle usage state exists. Specifically, step 24 detects the predetermined bicycle usage state when a torque above the threshold or a cadence above the threshold is applied to the pedals 16.

[0039] In step 26, in response to the detection of the predetermined bicycle usage state in step 24, the steering characteristics are changed back to the initial characteristics. This eliminates any changes to the steering characteristics, including the steering angle limitation, while riding.

[0040] In the embodiment described above, the front wheel 13 is held to the frame 11 via the fork, and the handlebar 10 is fixedly connected to the fork. Thus, the pivot angle of the handlebar 10 and the pivot angle of the fork are coupled and identical. In a further embodiment, a bicycle is provided in which the handlebar is not fixedly connected to the fork. Instead, in this further embodiment, the handlebar and the fork are each pivotably mounted to the frame. The bicycle also has steering actuators between the handlebar and the frame, as well as between the fork and the frame. This provides a steer-by-wire steering system for the bicycle. The steering actuators are designed to detect and change pivot angles. The steering actuators are controlled to couple a pivot angle of the handlebar and a pivot angle of the fork.During operation, the ratio between handlebar movement and fork movement can be adjusted in this further embodiment. As a result, the swivel angle of the handlebars and the swivel angle of the fork are not necessarily identical, but can differ. However, the handlebars and the fork usually move in at least the same direction. Reference sign 10 handlebars 11 frames 12 Steering adjustment system 13 front wheel 14 Detection device 15 rear wheel 16 pedals Step 20 / Detecting a push Step 22 / Changing a steering characteristic 24 steps / Recognizing a predetermined bicycle usage state Step 26 / Changing the steering characteristics back to an initial characteristic

Claims

[1] Method for steering a bicycle, wherein the method comprises a step (22) of changing a steering characteristic of a steering of the bicycle when the bicycle is pushed. [2] Method according to claim 1, characterized by , that the method includes a step (20) of detecting the pushing of the bicycle, wherein the steering characteristics are changed when the pushing of the bicycle is detected. [3] Method according to claim 2, characterized by , that the bicycle is designed as a pedelec and that pushing the bicycle is detected when a push assist function of the pedelec is activated. [4] Method according to any one of claims 1 to 3, characterized by , that the steering characteristics are changed back to an initial characteristic when a predetermined bicycle usage state is present. [5] Method according to claim 4, characterized by, that the predetermined bicycle usage state is present when a parameter of a steering operation is greater than a threshold value. [6] Method according to claim 4 or 5, characterized by , that the predetermined bicycle usage state is present when a parameter of a brake actuation is greater than a threshold value. [7] Method according to any of the preceding claims, characterized by , that changing the steering characteristics involves adjusting the steering resistance of the bicycle. [8] Method according to any of the preceding claims, characterized by , that changing the steering characteristics limits the maximum steering angle of the bicycle. [9] Method according to claim 8, characterized by , that the steering is locked when the bicycle is stationary by limiting the maximum steering angle to a predetermined position. [10] Method according to any of the preceding claims, characterized by, that changing the steering characteristics involves adjusting a restoring force of a steering return device. [11] Method according to claim 10, characterized by that the return device has a return spring, wherein the return spring force is set as a function of the steering angle by adjusting the return force. [12] Method according to any of the preceding claims, characterized by , that changing the steering characteristics involves adjusting the damping of the steering. [13] Steering adjustment system (12) for a bicycle, wherein the steering adjustment system (12) is designed to change a steering characteristic of a steering of the bicycle when the bicycle is pushed. [14] Steering adjustment system (12) according to claim 13, characterized by , that the steering adjustment system (12) further comprises a detection device (14) which is designed to detect when the bicycle is being pushed.

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