Electronic braking system

Abstract

Electronic braking system comprising a first housing (112, 212, 512) with a first cylinder chamber (111, 211, 511) hydraulically connected to a wheel brake unit (20), a first piston (113, 213, 513) connected to a pedal unit (10) to exert pressure on a working fluid stored in the first cylinder chamber (111, 211, 511) through the wheel brake unit (20), and a second cylinder chamber (121, 221, 521) connected to a reservoir unit (30) by a flow passage opened or closed by an electronic control valve (L131, L231, L531), wherein: a volume of the second cylinder chamber (121, 221, 521) is determined by a forward and backward movement of a second piston (123, 223, 523, 600), wherein the second piston (123, 223, 523, 600) is activated by at least one locking unit (150, 250, 550), characterized by the fact that, when the second piston (123, 223, 523, 600) is not activated by at least one locking unit (150, 250, 550), a forward and a backward movement of the second piston (123, 223, 523, 600) is independent of a forward force transmitted by the pedal unit (10) to the first piston (113, 213, 513) upon receiving a braking intention from a driver.

Description

BACKGROUND 1. Area

[0001] Embodiments of the present disclosure relate to an electronic braking system, and in particular to an electronic braking system for generating a braking force using an electrical signal corresponding to a displacement of a brake pedal. 2. Description of the state of the art

[0002] A braking system for braking a vehicle is essentially installed inside a vehicle, and various systems for obtaining a stronger and more stable braking force have been proposed recently.

[0003] Examples of braking systems include anti-lock braking systems (ABS) to prevent wheels from slipping during braking, brake slip control systems (BTCS) to prevent drive wheels from slipping during sudden unintended acceleration from a standstill or rapid acceleration of a vehicle, and electronic stability control systems (ESCs) to maintain a vehicle's driving condition by controlling hydraulic brake pressure through a combination of an anti-lock braking system (ABS) with a brake slip control system.

[0004] In general, an electronic brake contains an actuator. When a driver pushes a brake pedal, the actuator detects the pedal's displacement via a pedal displacement sensor and receives an electrical signal from the sensor indicating the driver's intention to brake, such that pressure is delivered to the wheel cylinder.

[0005] An electronic braking system equipped with such an actuator was disclosed in European Patent No. EP 2 520 473 A1. According to this European patent document, the actuator is configured to activate a motor in response to pedal actuation of a brake pedal to generate brake pressure. The brake pressure is generated by converting a rotational force from the motor into a linear motion to pressurize a piston. US Patent No. US 4 674 805 A describes a brake booster with anti-lock braking device for generating brake pressure and automatically modulating brake pressure in intrinsically safe closed brake circuits. By coupling a brake valve to a plunger and a booster piston, the latter travels essentially the same distance as the plunger during brake force amplification, so that the displacement of the booster piston is essentially proportional to the brake pedal travel. QUOTATED DOCUMENT PATENT DOCUMENT

[0006] European Patent No. EP 2 520 473 A1 (Honda Motor Co., Ltd.), (7 November 2012).

[0007] US Patent No. US 4 674 805 A (Robert Bosch GmbH), (June 23, 1987). SUMMARY

[0008] It is therefore an aspect of the present disclosure to specify an electronic braking system for generating a braking force using a dual-action actuator.

[0009] Another aspect of the present disclosure is to specify an electronic braking system that copes with a faulty operation of the actuator.

[0010] Additional aspects of the invention are partly reproduced in the following description and partly become apparent from the description, or they can be learned by carrying out the invention.

[0011] An electronic braking system according to the aforementioned aspects is defined in claim 1.

[0012] According to one aspect of the present disclosure, an electronic braking system comprises, in particular: a first housing with a first cylinder chamber hydraulically connected to a wheel brake unit; a first piston connected to a pedal unit such that a working fluid stored in the first cylinder chamber is pressurized by the wheel brake unit; and a second cylinder chamber connected to a reservoir by means of a flow passage opened or closed by an electronic control valve. The volume of the second cylinder chamber is determined by a forward and reverse movement of a second piston. The second piston is activated by at least one locking unit.If the second piston is not activated by at least one locking unit, a forward and backward movement of the second piston is independent of any forward force transmitted to the first piston by the pedal unit upon receiving a driver's intention to brake.

[0013] The locking unit can include a first projection part that is arranged on a push rod and configured to press directly against the second piston or indirectly against the second piston by means of an extension part arranged on the second piston.

[0014] The forward and backward movement of the first piston and the forward and backward movement of the second piston can be carried out independently either by an elastic element located between the multiple locking units or by an elastic element located between the second piston and the locking units.

[0015] The forward and backward movement of the first piston and the forward and backward movement of the second piston can be carried out independently either through a separation space and an elastic element arranged between the multiple locking units, or through a separation space and an elastic part arranged between the second piston and the locking units.

[0016] The electronic braking system may further include a movement limiting part, which is positioned and configured between the second piston and the locking units to limit a contraction range of the elastic element.

[0017] The electronic braking system may also include a volume-elastic unit that is hydraulically connected to the second cylinder chamber.

[0018] The electronic braking system may still include a first elastic part configured to provide an elastic force in a reverse direction of the first piston.

[0019] The second piston can come into contact with the first piston by the reverse movement of the first piston, and the second piston can move backward together with the first piston.

[0020] The electronic braking system may still include a first solid-type sealing element attached to an inner surface of the first housing.

[0021] The electronic braking system may also include a second housing configured to form a space in which the second piston moves back and forth.

[0022] The second housing can be connected in series with the first housing.

[0023] The first piston may contain an overhanging part that is guided through an inner surface of the second housing, in which the second piston moves forward and backward.

[0024] The overhang section may contain an overhang opening to create flow resistance.

[0025] The electronic braking system may further include a third piston, which is arranged on the front side of the first piston such that the first cylinder chamber and a third cylinder chamber are separated from each other by the third piston. Each of the first and third cylinder chambers is connected to at least one wheel brake unit.

[0026] The first piston or the third piston may contain a flow passage that is opened by a backward movement of the first or third piston or closed by a forward movement of the first or third piston.

[0027] The electronic braking system may further include a brake line configured to connect the first cylinder chamber and a wheel brake unit, and a reservoir line configured to connect the first cylinder chamber and a reservoir unit.

[0028] The electronic braking system may further include: a simulator line configured to connect the second cylinder chamber and a reservoir unit, and a check valve connected through the simulator line in parallel to the electronic control valve to allow only one-way flow in the area from the reservoir unit to the second cylinder chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] These and / or other aspects of the invention will become apparent and easier to understand with reference to the following description of the exemplary embodiments, which is given in conjunction with the accompanying drawings, in which: Fig. 1 is a view illustrating an electronic braking system according to a first embodiment of the present disclosure. Fig. 2 is a view illustrating an electronic braking system according to a second embodiment of the present disclosure. Fig. 3 is a view illustrating an electronic braking system according to a third embodiment of the present disclosure. Fig. 4 is a view illustrating an electronic braking system according to a fourth embodiment of the present disclosure. Fig. 5 is a view illustrating an electronic braking system according to a fifth embodiment of the present disclosure. Fig. 6 is a view illustrating an electronic braking system according to a sixth embodiment of the present disclosure. Fig. Figure 7 is a view illustrating an electronic braking system according to a seventh embodiment of the present disclosure. Fig. Figure 8 is a view illustrating an electronic braking system according to an eighth embodiment of the present disclosure. Fig. 9 is a view illustrating an electronic braking system according to a ninth embodiment of the present disclosure. Fig. 10 is a view illustrating an electronic braking system according to a tenth embodiment of the present disclosure. Fig. 11 is a view illustrating an electronic braking system according to an eleventh embodiment of the present disclosure. Fig. 12 is a view illustrating an electronic braking system according to a twelfth embodiment of the present disclosure. Fig. 13 is a view illustrating an electronic braking system according to a thirteenth embodiment of the present disclosure. Fig. 14 is a view illustrating an electronic braking system according to a fourteenth embodiment of the present disclosure. Fig. 15 is a view illustrating an electronic braking system according to a fifteenth embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. The embodiments to be described below are intended to fully convey the spirit of the present disclosure to a person skilled in the art. The present disclosure is not limited to the embodiments disclosed herein and may be implemented in other forms. In order to maintain clarity, some parts not related to the description have been omitted from the drawings and are not shown, and the size of the component may also be exaggerated or reduced for the sake of clarity.

[0031] Fig. Figure 1 is a view illustrating an electronic braking system according to a first embodiment of the present disclosure.

[0032] According to Fig. 1 The electronic braking system according to the first embodiment can include: a first cylinder part 110, a second cylinder part 120, a pedal unit 10, a wheel brake unit 20 and a reservoir unit 30.

[0033] The pedal unit 10 can transmit a forward force (or propulsive force) to a first piston 113 upon receiving a braking intention from the driver. The pedal unit 10 can include: a pedal part 11 for directly receiving a pedal actuation, a pivot part 12 which is pressed by the pedal part 11 so that it pivots about a hinge part 13, and a pushrod 14 connected to a first piston 113, which will be described later. The pedal unit 140 can be used for the electronic braking system, can receive an electrical signal indicating the driver's braking intention from a pedal displacement sensor, and can supply pressure to a first cylinder part 110, which will be described later, using the received electrical signal.

[0034] The wheel brake unit 20 can include a caliper pressurized by a working fluid and a wheel braked by the caliper. The wheel brake unit 20 can be pressurized by the working fluid supplied through a brake line L110 to brake wheels, thus generating a braking force in the vehicle.

[0035] The container unit 30 can be a means for storing the working fluid and supplying the working fluid to the brake system, and it can be a container whose upper part is provided with an inlet through which the working fluid can additionally be received from the external part. Although different types of container units 30 are shown in the respective drawings and the respective container units 30 are designated by the same reference numerals for the sake of simplicity, the scope or spirit of the disclosure is not limited thereto, and the container unit 30 can be formed from various component elements.

[0036] The first cylinder part 110 can include a first piston 113, a first elastic part 115, a first cylinder chamber 111, and a first sealing part 114. The first piston 113 can be connected to the pushrod 14 and can move forward or backward along an inner surface of a first housing 112 according to the actuation of the pedal unit 10. The first elastic part 115 can provide an elastic force to the first piston 113 in the backward direction. The first cylinder chamber 111 can hold the working fluid. The first sealing part 114 can seal a gap or space between the first piston 113 and the first housing 112.

[0037] The first housing 112 can have a gap or space in which the first piston 113 moves back and forth, and can form an opening in a flow passage to the reservoir unit 30 or the wheel brake unit 20. The first housing 112 can contain the first cylinder chamber 111, the volume of which is changed by the first piston 113.

[0038] The first cylinder chamber 111 may have a gap or space enclosed by the first piston 113 and the inner surface of the first housing 112, may store the working fluid therein, and may be pressurized by the pedal unit 10. Provided that the first cylinder chamber 111 is arranged to communicate with the brake line L110 via the reservoir line L120 under normal circumstances, the reservoir line L120 is closed when the first piston 112 moves forward in such a way that the working fluid is supplied to the brake line L110, enabling a braking force to be exerted in the wheel brake unit 20.

[0039] The first piston 113, which moves back and forth in the first cylindrical housing 112, can control the first cylinder chamber 111 so that, by actuating the pedal unit 10, its size is reduced to allow the working fluid to be supplied to the wheel brake unit 20. In this case, the first sealing element 114 can be arranged on the outer circumferential surface of the first piston 113 in such a way as to prevent the working fluid stored in the first cylinder chamber 111 from escaping during the return movement of the first piston 113.

[0040] The first elastic part 115 can be a compression spring that is compressed by a forward movement of the first piston 113 and provides an elastic force in the return direction of the piston 113. In this case, a forward movement of the first piston 113 can indicate that the first piston 113 is moving in the direction in which a volume of the first cylinder chamber 111 contracts (decreases), and a return movement of the first piston 113 can indicate that the first piston 113 is moving in the opposite direction, in which the volume of the first cylinder chamber 111 expands (increases).

[0041] The second cylinder part 120 can include: a second piston 123, a second cylinder chamber 121, a second sealing part 124, and a second elastic part 125. The second piston 123 can move forward or backward along the inner surface of the second housing 122 by means of an interaction unit 150 coupled to the push rod 14. The second cylinder chamber 121 can hold the working fluid. The second sealing part 124 can seal a gap or space between the second piston 123 and the first housing 112. The second elastic part 125 can supply an elastic force to the second piston 123. The volume of the second cylinder chamber 121 can be determined by the forward and backward movement of the second piston 123. The forward and backward movement of the first piston 113 can be carried out independently of the forward and backward movement of the second piston 123.

[0042] The second housing 122 can have a gap or space in which the second piston 123 moves back and forth, and it can form an opening in a flow passage to the container unit 30. The second housing 122 can contain the second cylinder chamber 121, the volume of which is changed by the second piston 123.

[0043] The second cylinder chamber 121 can have a gap or space enclosed by the second piston 123 and the inner surface of the second housing 122, can store the working fluid, and can have a volume that is variable by the second piston 123, which is pressurized by a first projecting part 152. The volume of the second cylinder chamber 121 is contracted (reduced) as the second piston 123 moves forward and then expanded (increased) as the second piston 123 moves back to its starting position by the second elastic part 125.

[0044] The second piston 123, which moves back and forth within the second cylindrical housing 122, can control the second cylinder chamber 121 so that it is contracted by a force supplied from the pedal assembly 120 through the first projection 152 to a projection 153, thus providing the driver of the vehicle with improved pedal feel. In this case, the second sealing element 124 can be arranged on the outer circumferential surface of the second piston 123 in such a way as to prevent the working fluid stored in the second cylinder chamber 121 from escaping during the return stroke of the second piston 123.

[0045] The second elastic part 125 can be a compression spring that is compressed by a forward movement of the first piston 113 and provides an elastic force in the return direction of the piston 123. In this case, the forward movement of the second piston 123 can indicate that the second piston 123 moves in the direction along which a volume of the second cylinder chamber 121 contracts (decreases), and the return movement of the second piston 123 can indicate that the second piston 123 moves in the direction along which a volume of the second cylinder chamber 123 expands (increases).

[0046] The elastic volume unit 130 can comprise a chamber 131, a piston 133, a housing 132, a sealing element 134, and an elastic part 135. The chamber 131 can store the working fluid. The housing 132 can form a space in which the piston 133 moves forward and backward. The sealing element 134 can seal the chamber 131. The elastic part 135 can provide an elastic force to the piston 133. In this case, the chamber 131 can be positioned relative to the elastic part 135 of the elastic volume unit 130 with respect to the piston 133.The chamber 131 of the elastic volume unit can be connected to the second cylindrical chamber 121 by a coupling part L140 in such a way that the chamber 131 of the elastic volume unit can quickly exchange the working fluid with the second cylindrical chamber 121.

[0047] In other words, the elastic volume unit 130 can have an empty space located on the front side of the piston 133 of the elastic volume unit, and the chamber 131 of the elastic volume unit can be located on the rear side of the piston 133 of the elastic volume unit. In this case, a forward movement of the piston 133 of the elastic volume unit can indicate that the piston 133 of the elastic volume unit is moving in the expansion direction of the chamber 131 of the elastic volume unit, and a backward movement of the piston 133 of the elastic volume unit can indicate that the piston 133 of the elastic volume unit is moving in the contraction direction of the chamber 131 of the elastic volume unit.

[0048] The locking unit 150 can be a means of transmitting a force received from the pedal unit 10 or the first cylinder part 110 to the second cylinder part 120. The locking unit 150 can include the first projection part 152 and the extension part 153. The first projection part 152 can project laterally towards the push rod 14. The extension part 153 can project towards the outside of the second housing 122 from the second piston 123 and can be spaced apart from the first projection part 152 by a separation distance 151.

[0049] The separation distance 151 allows the pedal unit 10 to press sequentially against the first cylinder part 110 and the second cylinder part 120. More precisely, after the first cylinder chamber 111 is compressed by the first piston 113 moving forward through the pedal unit 10, the first piston 113 moves forward by the separation distance 151 such that the first projection 152 then presses against the second piston 123. In this case, the first projection 152 can extend laterally along the push rod 14 and press against the extension 152 that is connected to the second piston 123 and projects outwards from the second housing 120.

[0050] The brake line L110 can connect the first cylinder chamber 111 with the wheel brake unit 20 and can supply the working fluid compressed by the contraction of the first cylinder chamber 111 to the caliper of the wheel brake unit 20 in such a way that a braking force can be delivered to the wheels.

[0051] The reservoir line L120 can connect the first cylinder chamber 111 to the reservoir unit 30 and can thus supply the working fluid stored in the reservoir unit 30 to the first cylinder chamber 111. In this case, the reservoir line L120 can be arranged adjacent to the front side of the first piston 113 within the first cylinder part 110, such that the reservoir line L120 can be closed by actuating the pedal unit 10. The actuated pedal unit 10 can enable the push rod 14 to press against the first piston 113, such that the first sealing element 114 can close a flow passage between the first cylinder chamber 111 and the reservoir line L120 by a forward movement of the first piston 113.

[0052] A simulator line L130 can connect the reservoir unit 30 to the second cylinder chamber 121 such that working fluid can be supplied to the second cylinder chamber 121 or returned to the reservoir unit 30. The simulator line L130 can include an electronic control valve L131 and a check valve L132. The electronic control valve L131 can be controlled by an electronic control unit (ECU). The check valve L132 can be arranged in parallel to the electronic control valve L131 and can allow the working fluid to flow only from the reservoir unit 30 to the second cylinder chamber 121. That is, the check valve L132 can act as a one-way valve. The ECU is a control device for setting an operating mode of the brake system.The ECU can open or close the electronic control valve L131 or the like according to a control scheme based on any of several different modes, for example a general operating mode, a substitute mode, etc.

[0053] The coupling part L140 can be a connector that is arranged between the second cylinder part 20 and the elastic volume unit 30 such that a volume of the chamber 131 of the elastic volume unit can be changed by pressure generated in the second cylinder chamber 121.

[0054] The electronic braking system according to the first embodiment has been disclosed as described above. The operating scheme of the aforementioned electronic braking system according to the first embodiment is described in detail below. The operating scheme of the electronic braking system according to the first embodiment can be broadly classified into a brake-by-wire mode, which is used in a general state, and a substitute mode, which is used in a faulty state, such that the electronic braking system can be operated by the ECU in different ways according to different situations.

[0055] In the brake-by-wire mode, the reservoir line L120 is opened by activating the pedal unit 10, and no pressure is exerted on the interior of the first cylinder chamber 111, so a braking force is not directly delivered to the wheel brake unit 20. However, pressure can occur in the second cylinder chamber 121 such that the driver of the vehicle can feel pedal actuation. In this case, the driver's braking intention can be delivered electrically. For example, an actuator (not shown) capable of electrically generating a braking force can be provided such that the braking force can be delivered to the wheel brake unit 20.

[0056] In the backup mode, which indicates a fault, the simulator line L130 can be opened by activating the pedal unit 10, such that no pressure is exerted on the second cylinder chamber 121. Then the brake line L110 is opened and the reservoir line L120 is closed, and pressure is exerted on the first cylinder chamber 111 such that a braking force is delivered directly from the first cylinder chamber 111 to the wheel brake unit 20.

[0057] As described above, the aforementioned components are combined in such a way that each of the first piston 113 and the second piston 123 can move forwards and backwards, such that the first cylinder chamber 111 and the second cylinder chamber 121 can be contracted at different times.

[0058] The electronic braking system described above according to the first embodiment can further include the elastic volume unit 130, which is provided with the chamber 131 for the elastic volume unit, which communicates with the second cylinder chamber 121, thereby providing a better pedal actuation (pedal feel) to the driver.

[0059] Fig. Figure 2 is a view illustrating an electronic braking system according to a second embodiment of the present disclosure. Fig. Figure 3 is a view illustrating an electronic braking system according to a third embodiment of the present disclosure. Fig. Figure 4 is a view illustrating an electronic braking system according to a fourth embodiment of the present disclosure. Fig. Figure 5 is a view illustrating an electronic braking system according to a fifth embodiment of the present disclosure. The following electronic braking systems according to the second to fifth embodiments, which are described in the Fig. Figures 2 to 5 show that the electronic braking system operates essentially identically to the first embodiment, and therefore a detailed description of this is omitted here for the sake of simplicity. Only the remaining elements, designated by additional reference numerals, are described below with reference to the Fig. 2 to 5 described.

[0060] According to Fig. 2. An elastic element 154 can be arranged instead of the separation space 151 between the first projection part 152 and the extension part 153. In a third embodiment according to Fig. 3 can be done in a similar way to in Fig. 2 the separation space 151 and the elastic element 154 are arranged between the first projection part 152 and the extension part 153.

[0061] The elastic element 154, arranged between the extension 153 and the first projection 152, can dampen impacts generated between the extension 153 and the first projection 152. The first projection 152 can move forward simultaneously with the forward movement of the push rod 14, such that the impact exerted on the extension 153 is reduced.

[0062] As described above, according to the second and third embodiments, the elastic element 154 can be inserted between the first projection part 152 and the second piston 123 in such a way that the first cylinder chamber 111 and the second cylinder chamber are contracted at different times and a shock generated by contact between the first projection part 152 and the second piston 123 is mitigated, thereby transmitting a better pedal feel to the driver of the vehicle.

[0063] According to a Fig. In the fourth embodiment shown in Figure 4, the push rod 14 can further include a second projection 155, and the second piston 123 can move backwards together with the first piston 113 through the first elastic part 115. In this case, a projection 153-1 can be provided with a stop projection formed in the lateral direction. During the backward movement of the second projection 153-a, the second projection 155 is caught in the stop projection such that the second piston 123 also moves backwards. As a result, a means for the backward movement (retraction) of the second piston 123 is not required, thus reducing manufacturing costs and enabling more efficient cylinder production.

[0064] Fig. Figure 5 is a view illustrating an electronic braking system according to a fifth embodiment of the present disclosure. Fig. 5. According to the fifth embodiment, the electronic braking system can include a first elastic part 115-1 to provide an elastic force in the return direction (retraction direction) of the first piston 113. The first elastic part 115-1 can be provided between the first projection 152 and a projection 112a located in the first housing 112. In contrast to the fourth embodiment, the electronic braking system according to the fifth embodiment is provided with the first elastic part 115-1 located outside the first housing 112.

[0065] Fig. Figure 6 is a view illustrating an electronic braking system according to a sixth embodiment of the present disclosure. Fig. Figure 7 is a view illustrating an electronic braking system according to a seventh embodiment of the present disclosure. Fig. Figure 8 is a view illustrating an electronic braking system according to an eighth embodiment of the present disclosure. Fig. Figure 9 is a view illustrating an electronic braking system according to a ninth embodiment of the present disclosure.

[0066] According to Fig. 6. According to the sixth embodiment, the electronic braking system can include a first cylinder part 210, a second cylinder part 220, a pedal unit 10, a wheel brake unit 20 and a reservoir unit 30.

[0067] The electronic braking system according to the sixth embodiment can contain the first cylinder part 210 within the second cylinder part 220. That is, a first housing 212 and a second housing 222 can be coupled in series such that the first housing 212 and the second housing 222 are integrated into a single body. In this case, a flow passage 212a can be formed between a second cylinder chamber 221 and the first housing 212, which is provided with the first cylinder chamber 211. The flow passage 212a can be open at an initial position of the first piston 212 and can be closed by forward movement of the first piston 213.

[0068] The first cylinder part 210 can generate hydraulic pressure in the first cylinder chamber 211 by means of the first piston 213, which is pressurized by the push rod 14, such that the working fluid can be supplied to the wheel brake unit 20 or the reservoir unit 30. The first cylinder part 210 can include the first housing 212, in which the first piston 213 is moved forwards and backwards, a first sealing part 214, which is arranged on the outer surface of the first piston 213 in such a way as to maintain an airtight seal with the first housing 212, and a first elastic part 215, which is arranged between a projection part 222a and a first projection part 252 (not shown) in such a way as to provide an elastic force.In this case, the first sealing part 214, which is located on the front side of the first piston 213, can prevent the working fluid from flowing between the first cylinder chamber 211 and the second cylinder chamber 221 during the forward movement of the first piston 213.

[0069] The first housing 212 can have a gap or space in which the first piston 213 moves back and forth, and can form an opening in a flow passage to the reservoir unit 30 or the wheel brake unit 20. The first housing 212 can contain the first cylinder chamber 211, the volume of which is changed by the first piston 213.

[0070] The first cylinder chamber 211 may have a gap or space enclosed by the first piston 213 and the inner surface of the first housing 212, can store the working fluid, and can be pressurized by the pedal unit 10. Provided that the first cylinder chamber 211 is arranged to communicate with the brake line L210 via the reservoir line L220 under normal operating conditions, the reservoir line L220 is closed when the first piston 212 moves forward in such a way that the working fluid is supplied to the brake line L210, enabling a braking force to be generated in the wheel brake unit 20.

[0071] The first piston 213, which moves back and forth in the first cylinder housing 212, can control the first cylinder chamber 211 so that it is contracted by actuation of the pedal unit 10, allowing the working fluid to be supplied to the wheel brake unit 20. In this case, the first sealing element 214 can be arranged on the outer circumferential surface of the first piston 213 in such a way as to prevent the working fluid stored in the first cylinder chamber 211 from escaping in the reverse direction of the first piston 213.

[0072] The first elastic part 215 can be a compression spring that is compressed by a forward movement of the first piston 213 and provides an elastic force in the return direction of the piston 213. In this case, the forward movement of the first piston 213 can indicate that the first piston 213 moves in the direction along which a volume of the first cylinder chamber 211 is contracted (decreased), and the return movement of the first piston 213 can indicate that the first piston 213 moves in the opposite direction, along which a volume of the first cylinder chamber 211 is expanded (increased). The first elastic part 215 can be arranged between the first projection 252, which is located on the push rod 14, and a projection 222a, which is located on the side of the second housing 222 described later.

[0073] The second cylinder part 220 can contain a second piston 223, a second cylinder chamber 221, and a second sealing part 224. The second piston 223 can move forward or backward along the inner surface of the second housing 222 by means of a locking unit 250 connected to the push rod 14. The second cylinder chamber 221 can hold the working fluid. The second sealing part 224 can seal a gap or space between the second piston 223 and the first housing 212. The volume of the second cylinder chamber 221 can be determined by the forward and backward movement of the second piston 223. The forward and backward movement of the first piston 213 and the forward and backward movement of the second piston 223 can be performed sequentially.

[0074] The second housing 222 can have a gap or space in which the second piston 223 moves back and forth, and can form an opening in a flow passage to the container unit 30. The second housing 222 can contain the second cylinder chamber 221, the volume of which is changed by the second piston 223.

[0075] The second cylinder chamber 221 can have a gap or space enclosed by the second piston 223, the inner surface of the second housing 222, and the outer surface of the first housing 212, and can store the working fluid. The volume of the second cylinder chamber 221 can be changed by the second piston 223, which is pressurized by the first projection 252. In this case, the volume of the second cylinder chamber 221 is compressed (reduced) as the second piston 223 moves forward, and then expanded (increased) when a projection 253 of the second piston 223 is caught by the first elastic part 215 in a second projection 255 arranged on the returning pushrod 14, thereby returning the second piston 223 to its initial position.

[0076] The second piston 223, which moves back and forth within the second cylindrical housing 222, can control the second cylinder chamber 221 so that it is contracted by a force supplied from the pedal assembly 20 through the first projection 252 to the extension 253, thus providing the driver of the vehicle with improved pedal feel. In this case, the second sealing element 224 can be positioned on each of the outer and inner circumferential surfaces of the second piston 223 such that it prevents the working fluid stored in the second cylinder chamber 221 from escaping during the return stroke of the second piston 223. A stop projection 222b arranged on the second housing 222 can determine an initial position of the second piston 223 and can limit the range of its return stroke.

[0077] The elastic volume unit 230 can include a chamber 231, a piston 233, a housing 232, a sealing element 234, and an elastic element 235. The chamber 231 can store the working fluid. The housing 232 can form a space in which the piston 233 moves forward and backward. The sealing element 234 can seal the chamber 231. The elastic element 235 can provide an elastic force for the piston 233.

[0078] In this case, chamber 231 of the elastic volume unit can be located opposite the elastic part 235 of the elastic volume unit on the basis of piston 233 of the elastic volume unit. Chamber 231 of the elastic volume unit can be connected to the second cylinder chamber 221 by the coupling part L240, such that chamber 231 of the elastic volume unit can exchange the working fluid with the second cylinder chamber 221.

[0079] In other words, the elastic volume unit 230 can have an empty space located at the front of the piston 233 of the elastic volume unit in the forward direction of the piston 233 of the elastic volume unit due to hydraulic pressure acting in the second cylinder chamber 221. The chamber 231 of the elastic volume unit can be located at the rear of the piston 233 of the elastic volume unit. In this case, a forward movement of the piston 233 can indicate that the piston 233 is moving in the expansion direction of the volume of chamber 231 of the elastic unit, and a backward movement of the piston 233 can indicate that the piston 233 is moving in the contraction direction of the volume of chamber 231 of the elastic unit.

[0080] The locking unit 250 can be a means of transmitting the force received from the pedal unit 10 or the first cylinder part 110 to the second cylinder part 220. The locking unit 250 can include the first projection 252 and the extension 253. The first projection 252 can project laterally towards the push rod 14. The extension 253 can project laterally towards the second piston 223 and can be arranged at a distance from the first projection 252 corresponding to a separation space 251. The forward and reverse movement of the first piston 213 can be carried out independently of the forward and reverse movement of the second piston 223.

[0081] An elastic element 254 and the separating space 251 can be arranged between the first projection part 252 and the extension part 253 or can be arranged between the first projection part 252 and the second piston 223, such that the forward and backward movement of the first piston 213 and the forward and backward movement of the second piston 223 can be carried out sequentially.

[0082] The separation chamber 251 can be configured such that pressure is first exerted on the first cylinder section and then on the second cylinder unit 220. The first cylinder chamber 211 is initially compressed by a forward movement of the first piston 213 caused by the pedal unit 10. The first piston 213 moves forward around the separation chamber 251, and the first projection 252 finally exerts pressure on the second piston 223. In this case, the first projection 252 can extend laterally along the push rod 14 and can exert pressure on the extension 253 arranged on the second piston 223 via the elastic element 254.

[0083] The elastic element 254 can be arranged between the extension part 253 and the first projection part 252 and can dampen a shock when the first projection part 252 is in contact with the extension part 253. The first projection part 252 can move forward simultaneously with the forward-moving push rod 14, thus reducing a shock exerted on the extension part 253.

[0084] The brake line L210 can connect the first cylinder chamber 211 to the wheel brake unit 20 and can supply the pressurized working fluid, generated by the contraction of the first cylinder chamber 211, to the caliper of the wheel brake unit 20, thus delivering a braking force to the wheels. The reservoir line L220 can connect the first cylinder chamber 211 to the reservoir line 30 and can therefore supply the working fluid stored in the reservoir unit 30 to the first cylinder chamber 211.

[0085] A simulator line L230 can connect the reservoir unit 30 to the second cylinder chamber 221 such that the working fluid can be supplied to the second cylinder chamber 221 or returned to the reservoir unit 30. The simulator line L130 can include an electronic control valve L231 and a check valve L232. The electronic control valve L231 can be controlled by the electronic control unit (ECU). The check valve L232 can be arranged in parallel to the electronic control valve L231 and can allow the working fluid to flow only from the reservoir unit 30 to the second cylinder chamber 221. That is, the check valve L232 can act as a one-way valve. The ECU is a control device for setting an operating mode of the brake system.The ECU can open or close the electronic control valve L231 or similar according to a control scheme based on any of several different modes, for example a general operating mode, a backup mode, etc.

[0086] The coupling element L240 can be a connector arranged between the second cylinder part 220 and the elastic volume unit 230, such that the volume of chamber 231 of the elastic volume unit can be changed by pressure generated in the second cylinder chamber 221. The electronic braking system according to the sixth embodiment has been disclosed as described above. In the sixth embodiment, the aforementioned components are combined in such a way that the first piston 213 and the second piston 223 can be moved sequentially forwards and backwards, such that the first cylinder chamber 211 and the second cylinder chamber 221 can be compressed at different times.

[0087] According to Fig. 7. According to the seventh embodiment, the electronic braking system can contain the first cylinder part 210 and the second cylinder part 220 in only one housing 260. The housing 260 can have a double-cylinder structure composed of two cylinder parts, each having a stepped section.

[0088] More precisely, the first piston 213 moves forward and backward in one of the two cylinder sections of the double-cylinder structure, and the second piston 223 moves forward and backward in the other of the two cylinder sections of the double-cylinder structure. The housing 260 can further include a projecting section 260a for supporting one end of the first elastic section 215 and a stop projection 260b for limiting the retraction range of the second piston 223.

[0089] According to Fig. In the eighth embodiment, the housing 260, in which the first cylinder part 210 and the second cylinder part 220, which are shown in the seventh embodiment, are received in one body, can contain a guide part 261 for guiding the movement of the first piston 213 and a fixed sealing part 262, which is attached to the inner wall of the housing 260.

[0090] According to Fig. According to the ninth embodiment, a movement-limiting element 256 can be provided in the elastic element 254 arranged between the extension part 253 and the first projection part 252 to limit the contraction range of the elastic element 254, such that the movement-limiting element 256 can prevent damage caused by excessive compression of the elastic element 254, thereby extending the service life of the elastic element 254.

[0091] Fig. Figure 10 is a view illustrating an electronic braking system according to a tenth embodiment of the present disclosure. Fig. Figure 11 is a view illustrating an electronic braking system according to an eleventh embodiment of the present disclosure. Fig. Figure 12 is a view illustrating an electronic braking system according to a twelfth embodiment of the present disclosure. Fig. In the tenth embodiment, the first piston 213 can include an overhang section 270 that is guided through the inner surface 260k of the housing 250 in which the second piston moves forward and backward. The overhang section 270 can be configured to compensate for the straightness of the first piston 223. In this case, the overhang section 270 can be provided with an overhang opening 270a that creates flow resistance and can prevent a sudden forward / backward movement of the first piston 223, thus resulting in increased stability.

[0092] According to Fig. In the eleventh embodiment, the housing can contain a chamber in which the first piston 213 and the second piston 223 move forwards and backwards. The first housing 212, forming the first cylinder chamber 211, and the second housing 222, forming the second cylinder chamber 221, can be connected in series. The first housing 212 and the second housing 222 can be connected in series. In this case, a sealing element 222k, which seals the first cylinder chamber 211, can be a solid-type sealing element arranged on one side of the second housing 222.

[0093] According to Fig. In the twelfth embodiment, a separate extension part is not coupled to the second piston 223, and the second piston 223 can be directly pressurized by the first piston 213, allowing the second piston 223 to move backward. In contrast to the eleventh embodiment, where the second piston 223 moves backward by means of the extension part 253 during the backward movement of the first piston 213, in the twelfth embodiment the second piston 223 can directly contact the first piston or the overhang part 270 during the backward movement of the first piston 213, so that in the twelfth embodiment the second piston 223 can move backward together with the first piston 213.

[0094] Fig. Figure 13 is a view illustrating an electronic braking system according to a thirteenth embodiment of the present disclosure. Fig. Figure 14 is a view illustrating an electronic braking system according to a fourteenth embodiment of the present disclosure. Fig. Figure 15 is a view illustrating an electronic braking system according to a fifteenth embodiment of the present disclosure.

[0095] According to Fig. 13. According to the thirteenth embodiment, the electronic braking system can comprise a first cylinder part 510, a second cylinder part 520, a pedal unit 10, and a reservoir unit 30. In the electronic braking system according to Fig. 13. The first cylinder part 520 can be attached in series to the second cylinder 520. That is, the first housing 512 and the second housing 522 are coupled in series, so that the first housing 512 and the second housing 522 can be embodied in one body.

[0096] The first cylinder part 510 can generate hydraulic pressure in the first cylinder chamber 511 by means of the first piston 513, which is pressurized by the push rod 14, such that the working fluid can be supplied to the wheel brake unit or the reservoir unit 30. The first cylinder part 510 can include the first housing 512, in which the first piston 513 moves forwards and backwards, and a first sealing part 514 of a solid type to maintain airtightness between the first piston 513 and the first housing 512.

[0097] The first housing 512 can have a space in which the first piston 513 moves back and forth, and can form an opening in a flow passage to the reservoir unit 30 or the wheel brake unit 20. The first housing 512 can contain the first cylinder chamber 511, the volume of which is changed by the first piston 513.

[0098] The first cylinder chamber 511 can have a space enclosed by the first piston 513 and the inner surface of the first housing 512, can store the working fluid, and can be compressed by the pedal unit 10. The first cylinder chamber 511 is provided to communicate with a first brake line L511 and a first reservoir line L521.

[0099] The first piston 513, which moves back and forth within the first cylindrical housing 512, can control the first cylinder chamber 511 so that it is compressed by actuation of the pedal unit 10, allowing the working fluid to be supplied to the wheel brake unit 20. In this case, the first sealing element 514 can be attached to the inner circumferential surface of the first housing 512 in such a way as to prevent the working fluid stored in the first cylinder chamber 511 from escaping in the reverse direction of the first piston 513. A third piston 543, which allows the first cylinder chamber 511 and the third chamber 541 to be separated from each other, can be arranged on the front side of the first piston 513, and each of the first cylinder chamber 511 and the third chamber 541 can be connected to at least one wheel brake unit.

[0100] The first elastic part 515 can be a compression spring that is compressed by the forward movement of the push rod 14 and provides an elastic force in the return direction of the piston 513. In this case, the forward movement of the first piston 513 can indicate that the first piston 513 is moving in the direction along which a volume of the first cylinder chamber 511 is compressed (reduced), and the return movement of the first piston 513 can indicate that the first piston 513 is moving in the opposite direction, along which a volume of the first cylinder chamber 511 is expanded (enlarged). The first elastic part 515 can be arranged between a first support part 557, which is located on the side of the second housing 522, and a second support part 558, which is located on the push rod 14.

[0101] An overhanging section 516, arranged on the rear side of the first piston 513, can be formed in a disc shape such that the overhanging section 516 has the same diameter as the inner diameter of the space in which the second piston 523 moves forward and backward within the second housing 522. The overhanging section 516 can be provided with an overhanging opening 516a, which creates flow resistance and can prevent a sudden forward / backward movement of the first piston 513, thereby increasing the stability of the braking system.

[0102] The second cylinder part 520 can include a second piston 523, a second cylinder chamber 521, and a second sealing part 524. The second piston 523 can move forward or backward along the inner surface of the second housing 522 by means of an interaction unit 550 coupled to the pushrod 14. The second cylinder chamber 521 can hold the working fluid. The second sealing part 524 can seal a gap or space between the second piston 523 and one of the first housing 512 and the second housing 522. The volume of the second cylinder chamber 521 can be determined by the forward and backward movement of the second piston 523. The forward and backward movement of the first piston 513 can be carried out independently of the forward and backward movement of the second piston 523.

[0103] The second housing 522 can have a gap or space in which the second piston 523 moves back and forth, and can form an opening in a flow passage to the container unit 30 or the elastic volume unit 530. The second housing 522 can contain the second cylinder chamber 521, the volume of which is changed by the second piston 523.

[0104] The second cylinder chamber 521 can have a gap or space enclosed by the second piston 523 and the inner surface of the second housing 522, can store the working fluid, and can have a volume that is variable by the second piston 523 being pressurized by a first projecting part 552. The volume of the second cylinder chamber 521 is compressed (reduced) as the second piston 523 moves forward and then expanded (increased) as the second piston 523 is pressurized by the first elastic part 515, which is caused by the overhanging part 516 arranged on the returning first piston 513, and then moves back to its initial position.

[0105] The second piston 523, which moves back and forth within the second cylindrical housing 522, can control the second cylinder chamber 521 so that it is compressed by the force supplied by the pedal assembly 10 via the first projection 522, thus providing the driver of the vehicle with improved pedal feel. In this case, the second sealing element 524 can be positioned on the second piston 523 to prevent the working fluid stored in the second cylinder chamber 521 from escaping during the return stroke of the second piston 523. A stop projection located on the second housing 522 can determine an initial position of the second piston 523 and can limit the range of its return stroke.

[0106] The elastic volume unit 530 can comprise a chamber 531, a piston 533, a housing 532, a sealing element 534, and an elastic part 535. The chamber 531 can store the working fluid. The housing 532 can form a space in which the piston 533 moves forward and backward. The sealing element 534 can seal the chamber 531. The elastic part 535 can provide an elastic force to the piston 533. In this case, the chamber 531 can be located opposite the elastic part 535 on the base of the piston 533. The chamber 531 of the elastic volume unit can be connected to the second cylinder chamber 521 by the coupling part L540 in such a way that the chamber 531 of the elastic volume unit can exchange the working fluid with the second cylinder chamber 521.This means that the chamber 531 of the elastic volume unit can be expanded when the piston 533 moves forward due to hydraulic pressure acting in the second cylinder chamber 521, and can be compressed when the piston 533 moves backward due to hydraulic pressure acting in the second cylinder chamber 521.

[0107] The third chamber 541 can be divided by the third piston 543 within the space pressed by the first piston 513 of the first housing 512. That is, the space pressed by the first piston 513 in the first housing 512 can be divided into the first cylinder chamber 511 and the third chamber 541. In this case, an opening 543a can be formed in the third piston 543, thereby creating flow resistance. The third sealing element 544 can seal the space between the third piston 543, the first cylinder chamber 511, and the third chamber 541. The third elastic element 545 can provide an elastic force in the expansion direction of the third chamber 541 towards the third piston 543.

[0108] The locking unit 550 can be a means of transmitting force supplied by the push rod 14 of the pedal unit 10 to the second cylinder part 120. The locking unit 150 can include the first projection 552 and the separating chamber 551. The first projection 552 can project laterally from the push rod 14. The separating chamber 551 can be arranged between the first projection 552 and the second piston 523 such that the forward and reverse movements of the first piston 513 and the second piston 523 can be performed sequentially.

[0109] The separating chamber 551 allows the pedal unit 10 to press sequentially against the first cylinder part 510 and the second cylinder part 520. More precisely, after the first cylinder chamber 511 is initially compressed by the first piston 513 moving forward through the pedal unit 10, the first piston 113 moves forward through the separating chamber 151 such that the first projecting part 522 then presses against the second piston 523. In this case, the first projecting part 552 can protrude laterally along the pushrod 14 and press against the second piston 126 as the pushrod 14 moves forward.

[0110] The brake line L510 can connect the first cylinder chamber 511 or the third chamber 541 to the wheel brake unit 20 and can supply the working fluid, which is pressurized by the compression of the first cylinder chamber 511 or the third chamber 541, to the caliper of the wheel brake unit 20 in such a way that a braking force can be delivered to the wheels. The reservoir line L520 can connect the first cylinder chamber 511 or the third chamber 541 to the reservoir unit 30 and can thus supply the working fluid stored in the reservoir unit 30 to the first cylinder chamber 511 or the third chamber 541.

[0111] A simulator line L530 can connect reservoir unit 30 to the second cylinder chamber 521 such that the working fluid can be supplied to the second cylinder chamber 521 or returned to reservoir unit 30. The simulator line L130 can include an electronic control valve L531 and a check valve 532. The electronic control valve L531 can be controlled by the ECU. The check valve 532 can be arranged in parallel with the electronic control valve L531 and can allow the working fluid to flow only from reservoir unit 30 to the second cylinder chamber 521. That is, the check valve L532 can act as a one-way valve. The ECU is a control device for setting an operating mode of the brake system. The ECU can control the electronic control valve L531 or the like according to a control scheme based on one of various modes, for example, a general operating mode, a backup mode, etc., open or close.

[0112] The coupling part L540 can be a connector arranged between the second cylinder part 520 and the elastic volume unit 530, such that a volume of the chamber 531 of the elastic volume unit can be changed by pressure generated in the volume of the second cylinder chamber 521.

[0113] The electronic braking system according to the thirteenth embodiment has been disclosed as described above. In the thirteenth embodiment, the aforementioned components are combined in such a way that the first piston 513 and the second piston 523 move sequentially forwards and backwards, so that the first cylinder chamber 511 and the second cylinder chamber 521 can be compressed at different times.

[0114] According to Fig. 4 In the fourteenth embodiment, an elastic element 560 can be arranged between the second housing 522 and the second piston 523 in such a way that the elastic element 560 can mitigate a shock exerted on the second housing 522 when the second piston 523 moves forward.

[0115] According to Fig. 15 According to the fifteenth embodiment, at a contact position between the overhang part 516 and the second piston 600 during the backward movement of the first piston 513, the second piston 600 can include a contact part 600a formed at the contact position and a movement-limiting part 600b that limits the contraction area of ​​the elastic element 610.

[0116] A first projection 620 can be coupled to the push rod 14 such that the first projection 620 can supply a forward force to the second piston 600 during activation of the push rod 14. An elastic element 610 can be arranged between the second piston 600 and the first projection 620, and the motion-limiting element 600b can allow the distance between the first projection 620 and the second piston 600 to be maintained at a predetermined or greater distance.

[0117] The electronic braking system according to the fifteenth embodiment has been disclosed as described above. The following electronic braking system is subsequently described with reference to the brake-by-wire mode (a), the non-operational mode (b), and the substitute mode (c), which are described in Fig.Figure 15 shows and describes the aforementioned operating modes (a), (b) and (c) which can be selectively operated by the ECU according to different situations.

[0118] In the brake-by-wire mode (a), during activation of the pedal unit 10, pressure is not exerted on the inside of the first cylinder chamber 511, such that a braking force is not delivered directly to the wheel brake unit, and pressure occurs in the second cylinder chamber 521, thus providing the driver with improved pedal feel. In this case, the driver's braking intention can be delivered electrically. For example, an actuator (not shown) for electrically generating a braking force can be arranged so that the braking force can be delivered to the wheel brake unit. In this case, pressure can be exerted on the elastic element 610, compressing it between the second piston 600 and the first projection part 520, and the movement-limiting part 600b can restrict the range of movement of the first projection part 520 such that the contraction range of the elastic element 610 can be limited.

[0119] In the non-operating mode (b) no forward force is exerted on the first piston 513, the elastic element 610 can return to its initial position, and the first piston 513 and the second piston 600 can each return to their initial positions by the elastic force of the first elastic part 515.

[0120] By using substitute mode (c), which indicates a fault condition, during activation of the pedal unit 10, pressure is not applied to the second cylinder chamber 521, and pressure is applied to the first cylinder chamber 511 and the third chamber 541 such that the braking force can be supplied directly from the first cylinder chamber 511 or the third chamber 541 to the wheel brake unit.

[0121] As can be seen from the foregoing description, the electronic braking system according to the embodiments of the present disclosure can enable the first piston and the second piston to move forward and backward successively, such that the first cylinder chamber and the second cylinder chamber are compressed at different times.

[0122] The electronic braking system can insert the elastic element between the first protruding part and the second piston in such a way that the first cylinder chamber and the second cylinder chamber are compressed at different times, and can mitigate a shock that is generated when the first protruding part is in contact with the second piston.

[0123] The movement restriction part for limiting the contraction range of the elastic part can be arranged between the second piston and the first projection part to prevent the elastic element from being compressed by more than a threshold range of the elastic element, in such a way as to prevent the elastic element from being damaged prematurely.

[0124] The electronic braking system according to the embodiments of the present disclosure can further include the elastic volume unit which is provided with a chamber of the elastic volume unit communicating with the second cylinder chamber, thereby giving the driver of the vehicle a better pedal feel.

[0125] The first cylinder part and the second cylinder part can have a double piston structure and can simultaneously receive an elastic force through a single elastic part when they move backwards, resulting in a reduction of wasted space and manufacturing costs.

[0126] Although few embodiments of the present disclosure have been shown and described, it is obvious to the person skilled in the art that changes can be made to these embodiments without leaving the scope of protection defined in the independent claim.

Claims

[1] Electronic brake system comprising a first housing (112, 212, 512) with a first cylinder chamber (111, 211, 511) hydraulically connected to a wheel brake unit (20), a first piston (113, 213, 513) connected to a pedal unit (10) to exert pressure on a working fluid stored in the first cylinder chamber (111, 211, 511) through the wheel brake unit (20), and a second cylinder chamber (121, 221, 521) connected to a reservoir unit (30) by a flow passage opened or closed by an electronic control valve (L131, L231, L531), wherein: a volume of the second cylinder chamber (121, 221, 521) is determined by a forward and backward movement of a second piston (123, 223, 523, 600), wherein the second piston (123, 223, 523, 600) is activated by at least one locking unit (150, 250, 550), characterized by , that, when the second piston (123, 223, 523, 600) is not activated by at least one locking unit (150, 250, 550), a forward and a backward movement of the second piston (123, 223, 523, 600) is independent of a forward force transmitted by the pedal unit (10) to the first piston (113, 213, 513) upon receiving a braking intention from a driver. [2] Electronic braking system according to claim 1, wherein the locking unit comprises (150, 250, 550): a first projecting part (152, 252, 552, 620) which is arranged and configured on a push rod (14) to press directly against the second piston (123, 223, 523, 600) or indirectly through an extension part (153, 153-1, 253) which is arranged on the second piston (123, 223, 523, 600) to press against the second piston (123, 223, 523, 600). [3] Electronic braking system according to one of the preceding claims, wherein the forward and reverse movement of the first piston (113, 213, 513) and the forward and reverse movement of the second piston (123, 223, 523, 600) are carried out independently either through a separation space (151, 251, 551) between the multiple locking units (150, 250, 550) or through a separation space (151, 251, 551) between the second piston (123, 223, 523, 600) and the locking units (150, 250, 550). [4] Electronic braking system according to one of the preceding claims, wherein the forward and reverse movement of the first piston (113, 213, 513) and the forward and reverse movement of the second piston (123, 223, 523, 600) are carried out independently either by an elastic element (154, 254, 610) arranged between the multiple locking units (150, 250, 550) or by an elastic element (154, 254, 610) arranged between the second piston (123, 223, 523, 600) and the locking units (150, 250, 550). [5] Electronic braking system according to one of the preceding claims, wherein the forward and reverse movement of the first piston (113, 213, 513) and the forward and reverse movement of the second piston (123, 223, 523, 600) are carried out independently either by a separation chamber (151, 251, 551) and an elastic element (154, 254, 610) arranged between several locking units (150, 250, 550), or by a separation chamber (151, 251, 551) and an elastic element (154, 254, 610) arranged between the second piston (123, 223, 523, 600) and the locking units (150, 250, 550). [6] Electronic braking system according to one of claims 4 and 5, further comprising: a movement restriction part (256, 600b) that is arranged between the second piston (123, 223, 523, 600) and the locking units (150, 250, 550) and is configured to restrict a range of contraction of the elastic element (154, 254, 610). [7] Electronic braking system according to any of the preceding claims, further comprising: an elastic volume unit (130, 230, 530) which is hydraulically connected to the second cylinder chamber (121, 221, 521). [8] Electronic braking system according to any of the preceding claims, further comprising: a first elastic part (115, 215, 515) configured to provide an elastic force in a reverse direction of the first piston (113, 213, 513). [9] Electronic braking system according to claim 8, wherein: the second piston (123, 223, 523, 600) is in contact with the first piston (113, 213, 513) by a backward movement of the first piston (113, 213, 513); and the second piston (123, 223, 523, 600) moves backwards together with the first piston (113, 213, 513). [10] Electronic braking system according to any of the preceding claims, further comprising: a first sealing element (114, 214, 514) of a solid type, which is attached to an inner surface of the first housing (112, 212, 512). [11] Electronic braking system according to any of the preceding claims, further comprising: a second housing (122, 222, 522) configured to form a space in which the second piston (123, 223, 523, 600) moves forward and backward. [12] Electronic braking system according to claim 11, wherein the second housing (122, 222, 522) is connected in series with the first housing (112, 212, 512). [13] Electronic brake system according to claim 12, wherein the first piston (113, 213, 513) contains: an overhang section (270, 516) which is guided through an inner surface of the second housing (122, 222, 522) in which the second piston (123, 223, 523, 600) moves forward and backward. [14] Electronic braking system according to claim 13, wherein the overhang part (270, 516) includes an overhang opening (270a, 516a) to generate flow resistance. [15] Electronic braking system according to any of the preceding claims, further comprising: a third piston (543) which is arranged on a front side of the first piston (113, 213, 513) such that the first cylinder chamber (111, 211, 511) and a third cylinder chamber (541) are separated from each other by the third piston (543), wherein each of the first cylinder chamber (111, 211, 511) and the third cylinder chamber (541) is connected to at least one wheel brake unit (20). [16] Electronic braking system according to claim 15, wherein the first piston (113, 213, 513) or the third piston (543) includes a flow passage (212a) which is opened by backward movement of the first (113, 213, 513) or the third piston (543) or is closed by forward movement of the first (113, 213, 513) or the third piston (543). [17] Electronic braking system according to any of the preceding claims, further comprising: a brake line (L110, L210; L510) configured to connect the first cylinder chamber (111, 211, 511) and the wheel brake unit (20); and a container line (L120, L220, L520) configured to connect the first cylinder chamber (111, 211, 511) and the container unit (30). [18] Electronic braking system according to any of the preceding claims, further comprising: a simulator line (L130, L230, L530) configured to connect the second cylinder chamber (121, 221, 521) and the tank unit (30); and a check valve (L132, L232, L532) which is arranged parallel to the electronic control valve (L131, L231, L531) through the simulator line (L130, L230, L530) such that only a one-way flow is permitted in the area from the container unit (30) to the second cylinder chamber (121, 221, 521).

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