Hydraulic brake system of a bicycle

Abstract

The present invention relates to a hydraulic brake system of a bicycle, in particular an electric bicycle, comprising a hydraulic unit, which is designed to modulate a hydraulic brake pressure, a control unit, which is designed for the controlled actuation of the hydraulic unit, a brake caliper, and a first brake line, which hydraulically connects the hydraulic unit and the brake caliper to each other, wherein the hydraulic unit does not have a pump, and wherein the brake system is designed to provide a predetermined minimum hydraulic rigidity between the hydraulic unit and the brake caliper.

Description

[0001] Description

[0002] title

[0003] Hydraulic braking system of a bicycle

[0004] State of the art

[0005] The present invention relates to a hydraulic brake system of a bicycle, in particular an electric bicycle, and an electric bicycle.

[0006] Hydraulic brake systems for bicycles, such as electric bicycles, that include an anti-lock braking system are known. Such a braking system typically includes a hydraulic unit configured to modulate brake pressure on a brake caliper to provide the anti-lock function. Particularly on bicycles, simple braking systems are often used to minimize complexity, weight, and cost. However, this often results in limitations in performance and user comfort.

[0007] Disclosure of the invention

[0008] The hydraulic brake system according to the invention with the features of claim 1 is characterized in that optimal braking performance and high user comfort can be provided with a particularly simple and cost-effective design. This is achieved according to the invention by a hydraulic brake system of a bicycle, preferably an electric bicycle, comprising a hydraulic unit, a control unit, a brake caliper, and a first brake line. The hydraulic unit is configured to modulate a hydraulic brake pressure. The control unit is configured for the controlled actuation of the hydraulic unit, in particular in response to one or more sensor signals from at least one sensor, for example at least one wheel speed sensor. The first brake line hydraulically connects the hydraulic unit and the brake caliper to one another, in particular directly. The hydraulic unit is designed to be pumpless.This means that the hydraulic unit does not have a pump specifically designed to recirculate hydraulic fluid from the first brake line, for example, toward a brake piston. The braking system is designed to provide a predetermined minimum hydraulic stiffness between the hydraulic unit and the brake caliper.

[0009] In particular, hydraulic stiffness is considered to be a relationship between an elongation of the first brake line and a change in force acting, in particular, on the hydraulic fluid inside the first brake line. The hydraulic stiffness preferably defines a linear relationship between the elongation and the change in force acting. This means that the hydraulic stiffness is preferably a constant, which depends in particular on the material properties and / or geometric properties of the hydraulic brake system.

[0010] For example, the hydraulic stiffness can be considered analogous to a spring constant according to Hooke's law.

[0011] In other words, a hydraulic braking system is provided which has a pumpless hydraulic unit and which has a predetermined high hydraulic stiffness between the hydraulic unit and the brake caliper.

[0012] The hydraulic braking system offers the advantage that a particularly direct implementation of the modulation of the hydraulic brake pressure by means of the hydraulic unit is possible in the area of ​​the hydraulic braking system relevant for braking performance, namely at the brake caliper. In detail, when the hydraulic brake pressure is modulated by the hydraulic unit, the brake pressure at the brake caliper is briefly and periodically reduced in order to provide the anti-lock function. Because the hydraulic unit is designed without a pump, a certain amount of the brake fluid between the hydraulic unit and the brake caliper is taken from this area each time the brake pressure is reduced and fed to an accumulator, for example. In particular, this has the effect that when the pressure is reduced several times by means of the hydraulic unit, the brake lever moves continuously towards the handlebars during the braking process.The high hydraulic stiffness in the area between the hydraulic unit and the brake caliper keeps the volume of brake fluid required by the hydraulic unit to achieve a specific pressure reduction extremely low. This enables a particularly direct transfer of brake pressure between the hydraulic unit and the brake caliper. This allows, for example, an increased control frequency of the hydraulic unit for the anti-lock function, allowing for faster response to changes in the road surface's friction coefficient. Furthermore, an increased control duration can be provided, for example, for longer downhill rides.

[0013] The subclaims show preferred developments of the invention.

[0014] Preferably, the minimum hydraulic stiffness is at least 1 .0 mm 3 / bar, in particular at least 1.5 mm 3 / bar. This allows for particularly reliable, high hydraulic stiffness to be provided, enabling optimal, direct, and efficient implementation of pressure modulation using the hydraulic unit.

[0015] Particularly preferably, the hydraulic brake system further comprises a second brake line, which hydraulically connects the hydraulic unit and a brake piston, which is preferably also part of the brake system. The hydraulic brake system is designed to provide a predetermined maximum overall hydraulic stiffness. Preferably, the maximum overall hydraulic stiffness is 5.0 mm. 3 / bar, preferably maximum 4.5 mm 3 / bar. This allows for optimal deceleration, especially for a wide range of bicycles of common sizes and weights, such as trekking bikes or mountain bikes. The maximum overall hydraulic stiffness is preferably 2.5 mm. 3 / bar. This allows for particularly advantageous and efficient braking performance, for example, for bicycles in higher weight categories, such as cargo bikes. Preferably, a second brake line with low hydraulic stiffness can be used to provide maximum overall hydraulic stiffness while maintaining high stiffness in the first brake line. This enables optimal brake lever feel during manual operation by the rider, thus also providing a high level of user comfort.

[0016] Preferably, the predetermined minimum hydraulic stiffness is provided by connecting the hydraulic unit to the brake caliper with a correspondingly short first brake line. In other words, high stiffness is provided by providing the first brake line with a short hydraulic line length. Since a short brake line has less material that can expand when the brake pressure changes, the high hydraulic stiffness can be provided in a particularly simple and cost-effective manner.

[0017] Preferably, a line length of the first brake line is a maximum of 0.2 m, particularly preferably a maximum of 0.1 m. This allows the pressure modulation from the hydraulic unit to the brake calliper to be transmitted particularly directly with low material usage and thus a simple and cost-effective construction.

[0018] More preferably, the predetermined minimum hydraulic stiffness is provided by a high stiffness of the first brake line. This means that, through appropriate design and configuration of the first brake line, the predetermined minimum hydraulic stiffness is ensured between the hydraulic unit and the brake caliper. In particular, the first brake line exclusively forms a direct hydraulic connection between the hydraulic unit and the brake caliper. This enables a direct, hydraulically optimal connection using particularly simple means.

[0019] Preferably, the high rigidity of the first brake line is provided by a stiffening braid, which preferably comprises a Kevlar braid and / or a steel braid. This ensures low elongation and thus high rigidity of the first brake line in a simple and reliable manner, while maintaining low weight and high flexibility.

[0020] Particularly preferably, the hydraulic unit and the control unit are designed together as a single, in particular one-piece, brake unit. This means that the hydraulic unit and control unit together form a single, manageable component. This allows for a particularly simple, cost-effective, and compact design of the brake system, which also allows for easy installation. The brake unit can preferably be arranged near the brake caliper, for example, on a fork or on the rear frame of the bicycle.

[0021] Furthermore, the hydraulic braking system comprises at least one sensor, preferably an inertial sensor. The sensor is particularly designed to determine a wheel speed. The braking unit preferably comprises the at least one sensor. This further simplifies the design and installation space of the braking system. Furthermore, optimal detection of desired variables, such as accelerations and / or rotation rates, can be enabled to ensure particularly precise operation of the anti-lock braking system control. For example, this allows for dynamic adjustment of the anti-lock braking operation to be carried out particularly efficiently and effectively.

[0022] More preferably, the hydraulic braking system comprises two brake calipers and one hydraulic unit per brake caliper. The braking system further comprises exactly one common control unit for both hydraulic units. This means that the one common control unit is configured to actuate each of the two hydraulic units in a controlled manner. In this case, the control unit is preferably arranged together with one of the two hydraulic units in one braking unit. Alternatively, the braking system preferably comprises a separate control unit for each hydraulic unit. In this case, one hydraulic unit is preferably designed together with the respective control unit as one braking unit. Such a hydraulic braking system with two separate braking units can also be referred to as a two-channel system. One of the braking units can preferably be assigned to a front wheel and the other braking unit to a rear wheel.Alternatively, the respective control unit of the respective hydraulic unit or the one common control unit of the two hydraulic units can be designed separately. Such a control unit separate from the hydraulic unit(s) can, for example, be housed in another component of a bicycle, in particular an electric bicycle. The control unit can, for example, be arranged in a drive unit or an energy storage device of an electric bicycle. The control unit of the hydraulic braking system can also be provided in a control device of a drive system of a bicycle, in particular an electric bicycle. The control device of the drive system can be designed separately from one of the components of the drive system, wherein the components of the drive system include, in particular, the hydraulic braking system, the drive unit and the energy storage device.

[0023] The hydraulic braking system further comprises signal and / or voltage lines that connect the control unit and the hydraulic unit to each other in terms of signals and / or voltage. The signal and / or voltage lines are designed to transmit electrical signals for controlling the hydraulic units and / or to provide electrical voltage for supplying the hydraulic units. In particular, the control unit and the hydraulic unit can communicate with each other to ensure optimal operation of the bicycle.

[0024] Preferably, the hydraulic braking system is designed and arranged such that the signal and / or voltage lines and / or brake lines branch off on opposite sides of the hydraulic unit and / or the control unit. This means that the lines on the hydraulic unit and / or the control unit are arranged such that lines leading in opposite directions are arranged on opposite sides of the hydraulic unit or the control unit. This allows line lengths to be kept to a minimum, providing a particularly simple, compact, and cost-effective design for the electric bicycle.

[0025] The invention further relates to a drive system for a bicycle, in particular an electric bicycle, comprising the above-described hydraulic braking system and a drive unit. The drive unit of a bicycle, in particular an electric bicycle, comprises an electric motor for providing a motor torque, which is provided in addition to and / or alternatively to the rider torque. In one embodiment of such a drive system, the control unit is arranged in the drive unit.

[0026] Furthermore, the invention leads to a bicycle, in particular an electric bicycle, comprising the described hydraulic braking system or the described drive system.

[0027] Short description of the drawings

[0028] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. Figure 1 is a simplified schematic view of an electric bicycle with a hydraulic braking system according to a first embodiment of the invention.

[0029] Figure 2 is a simplified schematic detailed view of the hydraulic braking system of Figure 1,

[0030] Figure 3 is a simplified schematic view of an electric bicycle with a hydraulic braking system according to a second embodiment of the invention,

[0031] Figure 4 is a simplified schematic view of an electric bicycle with a hydraulic braking system according to a third embodiment of the invention, and

[0032] Figure 5 is a simplified schematic view of an electric bicycle with a hydraulic braking system according to a fourth embodiment of the invention.

[0033] Embodiments of the invention

[0034] Preferably, all identical components, elements and / or units in all figures are provided with the same reference numerals.

[0035] Figure 1 shows a simplified schematic view of an electric bicycle 100 according to a preferred embodiment of the invention. The electric bicycle 100 includes a drive unit 50 configured to assist the pedaling power of a rider of the electric bicycle 100 using motor power.

[0036] The drive unit 50 is supplied with electrical energy by an electrical energy storage device 109 of the electric bicycle 100.

[0037] The electric bicycle 100 comprises a hydraulic braking system 10 by means of which brakes 8, which are designed in particular as brake discs, can be actuated on a front wheel and a rear wheel of the electric bicycle 100, respectively. Figure 2 shows a simplified schematic detailed view of the hydraulic braking system 10 of Figure 1.

[0038] The hydraulic brake system 10 comprises, for each brake 8, a brake lever 71, a brake piston 7, a brake calliper 4, a hydraulic unit 2, a control unit 3, a first brake line 5, and a second brake line 6.

[0039] The first brake line 5 hydraulically connects the hydraulic unit 2 and the brake calliper 4, and the second brake line 6 connects the brake piston 7 and the hydraulic unit 2.

[0040] The hydraulic unit 2 is designed without a pump and is configured to modulate a hydraulic brake pressure during anti-lock operation of the hydraulic brake system 10. For this purpose, in the event of a locked wheel, which can preferably be determined by means of a sensor 9 designed as a wheel speed sensor, the driver can be hydraulically separated from the brake caliper 4 by the hydraulic unit 2. In this state, the hydraulic unit 2 can reduce a brake pressure at the brake caliper 4, in particular by storing brake fluid located between the hydraulic unit 2 and the brake 8, i.e., in the first brake line 5 and at the brake caliper 4, in an accumulator of the hydraulic unit 2. The operation of the hydraulic unit 2 is controlled by the control unit 3.

[0041] The hydraulic brake system 10 according to the invention is designed such that a predetermined high hydraulic stiffness exists between the hydraulic unit 2 and the brake caliper 4. In particular, the hydraulic stiffness is at least 1.5 mm 3 / bear.

[0042] The hydraulic stiffness is crucial for the brake lever feel for the driver and is also relevant for optimal implementation of the anti-lock braking system.

[0043] The high rigidity between hydraulic unit 2 and brake caliper 4 ensures that, in anti-lock mode, only a small volume of brake fluid needs to be stored in the accumulator for the intended reduction in brake pressure at brake caliper 4. This eliminates the need to replenish the missing volume of brake fluid from brake piston 7 to maintain braking performance, which would cause brake lever 71 to move increasingly closer to handlebar 72. In addition to increasing user comfort for the rider of electric bicycle 100, this also provides the advantage of particularly direct and effective brake pressure control by means of hydraulic unit 2. Furthermore, anti-lock mode can be provided over a particularly long period of time and thus for long braking maneuvers, for example, during extended downhill rides.

[0044] The high rigidity is achieved by the first brake line 5 having a short line length. This means that the hydraulic unit 2 is positioned particularly close to the brake caliper 4 thanks to a short first brake line 5. Alternatively or additionally, the first brake line 5 can have a stiffening braid, such as a Kevlar braid and / or a steel braid, to provide the increased rigidity.

[0045] As can be seen in Figure 1, a separate hydraulic unit 2 is provided for each brake 8. The two hydraulic units 2 are each arranged correspondingly close to the respective brake 8. In the first embodiment of Figure 1, the hydraulic braking system 10 comprises a common control unit 3 for both hydraulic units 2. The common control unit 3 is configured to actuate both hydraulic units 2 in a controlled manner.

[0046] The common control unit 3 can be arranged on a handlebar 72 or near the handlebar 72 of the electric bicycle 100.

[0047] Figure 3 shows a simplified schematic view of an electric bicycle 100 with a hydraulic braking system 10 according to a second exemplary embodiment of the invention. The second exemplary embodiment essentially corresponds to the first exemplary embodiment of Figures 1 and 2, with the difference that a separate control unit 3 is provided for each hydraulic unit 2. Each of the two control units 3 is assigned to the corresponding hydraulic unit 2 and arranged directly adjacent to it. The hydraulic unit 2 and the control unit 3 together form a braking unit 15, which is designed in particular as a one-piece unit. This makes it possible to provide a distributed, two-channel braking system 10. Preferably, each braking unit 15 can additionally comprise a sensor 9, such as an inertial sensor.This makes it possible, for example, to detect accelerations and movements directly on the wheels of the electric bicycle 100 in order to provide optimal control of the anti-lock braking operation.

[0048] Figure 4 shows a simplified schematic view of an electric bicycle 100 with a hydraulic braking system 10 according to a third embodiment of the invention. The third embodiment essentially corresponds to the first embodiment of Figures 1 and 2, with the difference of an alternative arrangement of the control unit 3 and an alternative wiring.

[0049] In detail, in the third exemplary embodiment, the control unit 3 is integrated into the drive unit 50. A signal and / or voltage line 55 leads from the control unit 3 to each hydraulic unit 2 in order to transmit electrical signals for controlling the hydraulic units 2 and / or electrical voltage for supplying the hydraulic units 2.

[0050] The signal and / or voltage lines 55 branch off from opposite sides of the control unit 3. Furthermore, the signal and / or voltage lines 55 and the first brake lines 5 are connected to each hydraulic unit 2 on opposite sides. This allows for particularly efficient cabling and line routing of the hydraulic brake system 10. In particular, line lengths can be minimized, enabling a particularly simple, cost-effective, and compact arrangement of the hydraulic brake system 10.

[0051] Figure 5 shows a simplified schematic view of an electric bicycle 100 with a hydraulic braking system 10 according to a fourth embodiment of the invention. The fourth embodiment essentially corresponds to the third embodiment of Figure 4, with the difference of an alternative braking actuation of the rear wheel.

[0052] In the fourth embodiment of Figure 5, the hydraulic unit 2 of the front wheel is connected to the brake caliper 4 of the rear wheel via a first brake line 5. Thus, the hydraulic unit 2 on the front wheel is provided solely for modulating the brake pressure on both wheels of the electric bicycle 100. A modified hydraulic unit 2' can be provided on the rear wheel, which, for example, can be provided only for detecting sensor variables for anti-lock braking operation. The signal and / or voltage lines 55 correspond in their arrangement to the signal and / or voltage lines 55 according to the embodiment variant in Figure 4.

Claims

Claims 1. Hydraulic braking system of a bicycle (100), in particular an electric bicycle, comprising: a hydraulic unit (2) which is configured to modulate a hydraulic braking pressure, a control unit (3) which is configured for the controlled actuation of the hydraulic unit (2), a brake caliper (4), and a first brake line (5) which hydraulically connects the hydraulic unit (2) and the brake caliper (4) to one another, wherein the hydraulic unit (2) is designed without a pump, and wherein the braking system (10) is designed to provide a predetermined minimum hydraulic stiffness between the hydraulic unit (2) and the brake caliper (4).

2. Hydraulic brake system according to claim 1, wherein the minimum hydraulic stiffness is at least 1.0 mm 3 / bar, preferably at least 1.5 mm 3 / bar.

3. Hydraulic brake system according to one of the preceding claims, further comprising a second brake line (6) which hydraulically connects the hydraulic unit (2) and a brake piston (7) to one another, wherein the brake system (10) is designed to provide a predetermined maximum overall hydraulic stiffness, in particular wherein the maximum overall hydraulic stiffness is a maximum of 5.0 mm 3 / bar, preferably maximum 4.5 mm 3 / bar, preferably maximum 2.5 mm 3 / bar.

4. Hydraulic brake system according to one of the preceding claims, wherein the predetermined minimum hydraulic stiffness is provided by connecting the hydraulic unit (2) to the brake calliper (4) with a correspondingly short first brake line (5).

5. Hydraulic brake system according to claim 4, wherein a line length of the first brake line (5) is a maximum of 0.2 m, preferably a maximum of 0.1 m.

6. Hydraulic brake system according to one of the preceding claims, wherein the predetermined minimum hydraulic stiffness is provided by a high stiffness of the first brake line (5).

7. Hydraulic brake system according to claim 6, wherein the high rigidity of the first brake line (5) is provided by a stiffening braid, in particular a Kevlar braid and / or a steel braid.

8. Hydraulic brake system according to one of the preceding claims, wherein the hydraulic unit (4) and the control unit (5) are jointly designed as a brake unit (15).

9. Hydraulic brake system according to claim 8, wherein the brake unit (15) further comprises at least one sensor (9), in particular an inertial sensor.

10. Hydraulic brake system according to one of the preceding claims, comprising two brake callipers (4) and one hydraulic unit (2) per brake calliper (4), and further comprising exactly one common control unit (3) for both hydraulic units (2).

11. Hydraulic brake system according to one of claims 1 to 9, comprising two brake callipers (4) and one hydraulic unit (2) per brake calliper (4), and further comprising one separate control unit (3) per hydraulic unit (2).

12. Hydraulic brake system according to one of claims 10 or 11, comprising signal and / or voltage lines (55) which connect the control unit (3) and the hydraulic unit (2) to one another.

13. Hydraulic brake system according to claim 12, wherein signal and / or voltage lines (55) and / or brake lines (5, 6) branch off on opposite sides of the hydraulic unit (2) and / or the control unit (3).

14. Drive system for a bicycle, in particular an electric bicycle, comprising a hydraulic braking system (10) according to one of the preceding claims and a drive unit (50).

15. Drive system according to claim 14, wherein the control unit (3) is arranged in the drive unit (50).

16. Bicycle, in particular electric bicycle, comprising a drive system according to one of claims 14 or 15.

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