Brake system for vehicles

Abstract

Braking device for vehicles, comprising: a cylinder with a first port through which the working fluid moves; a motor designed to generate rotational force; a screw shaft which is arranged in the cylinder and is designed to receive the rotational force from the engine and to rotate axially; a nut that is coupled to the screw shaft and is designed to move back and forth in an axial direction of the screw shaft in response to a rotation of the screw shaft; a shaft bearing that is located in the cylinder and is coupled to the screw shaft; a sleeve arranged between the cylinder and the screw shaft, having a first end that is closed and faces the shaft bearing, and a second end that is open and opposite the first end, the sleeve being in contact with and supported by the cylinder between the first connection and the second end; and a piston that is coupled to the nut and is designed to move back and forth within the sleeve in response to a back-and-forth movement of the nut.

Description

Background area

[0001] Exemplary embodiments of the present disclosure relate to braking devices for vehicles and in particular to a braking device for vehicles in which a rotary motion of a screw shaft generated by the rotational force of a motor can be converted into a linear motion of a piston. Discussion of the background

[0002] Due to the characteristics of electrically operated braking devices for vehicles, a mechanism is generally required that is set up to convert a rotary motion of a motor into a linear motion of a piston in a cylinder in order to build up hydraulic brake pressure.

[0003] A ball screw drive is used in an electric brake device as the mechanism to convert the rotary motion of the motor into linear motion. The ball screw drive comprises a screw shaft that receives a rotary force from the motor and rotates about an axis, a nut that is coupled to the screw shaft via balls and is configured to move in an axial direction along the screw shaft, and a piston that is coupled to the nut and is configured to pressurize a working fluid in the cylinder.

[0004] In the prior art, if the piston moves forward and backward to generate hydraulic pressure, a gap can form in a sealing structure that builds up the hydraulic pressure if a central axis is excessively inclined, resulting in a leakage problem.

[0005] The technical background of the present disclosure is disclosed in Korean patent disclosure no. 10-2021-0064367 (published on June 2, 2021, entitled “Hydraulic unit for hydraulic vehicle braking system”). Summary

[0006] Various embodiments aim to provide a braking device for vehicles in which leakage between a sleeve and a cylinder can be prevented by suppressing any wobbling of the sleeve.

[0007] A braking device for vehicles according to an embodiment of the present disclosure may comprise the following: a cylinder with a first port through which the working fluid moves; a motor configured to generate rotational force; a screw shaft arranged in the cylinder and configured to receive the rotational force from the motor and to rotate axially; a nut coupled to the screw shaft and configured to move back and forth in an axial direction of the screw shaft in response to a rotation of the screw shaft; a shaft bearing arranged in the cylinder and coupled to the screw shaft;a sleeve arranged between the cylinder and the screw shaft, having a first end that is closed and facing the shaft bearing, and a second end that is open and opposite the first end, the sleeve being brought into contact with and supported by the cylinder between the first end and the second end; and a piston coupled to the nut and arranged to move back and forth within the sleeve in response to a reciprocating motion of the nut.

[0008] The cylinder may further have a second port, spaced apart from the first port in the direction of the first end of the sleeve. The sleeve may be brought into contact with the cylinder between the first port and the second port and be supported by it.

[0009] The cylinder may include a contact projection that is in surface contact with an outer surface of the sleeve between the first terminal and an area facing the second end.

[0010] The contact protrusion can be formed along the circumference of an inner surface of the cylinder.

[0011] A guide groove can be formed in the contact projection, whereby the guide groove directs the working fluid in the sleeve to the first connection.

[0012] The guide groove can comprise a plurality of guide grooves arranged at fixed intervals in the contact projection.

[0013] The guide grooves formed in the contact projection can be oriented obliquely to a central axis of the cylinder. Brief description of the drawings Fig. Figure 1 is a sectional view showing a braking device for vehicles according to an embodiment of the present disclosure. Fig. Figure 2 is a perspective view showing a cylindrical unit according to an embodiment of the present disclosure viewed from one direction. Fig. Figure 3 is a perspective view showing the cylinder unit. Fig. 2 is viewed from a different direction. Fig. Figure 4 is a sectional view schematically representing the braking device for vehicles according to an embodiment of the present disclosure. Fig. Figure 5 is a perspective view that schematically represents an interior of the cylinder according to an embodiment of the present disclosure. Fig. Figure 6 is a view illustrating an operating condition in which a piston moves forward in the cylinder of the brake device for vehicles according to an embodiment of the present disclosure. Fig. Figure 7 is a view illustrating an operating condition in which the piston in the cylinder of the brake device for vehicles according to an embodiment of the present disclosure moves backwards. Detailed description

[0014] The following describes embodiments of a braking device for vehicles according to the present disclosure with reference to the accompanying drawings. It should be noted that the drawings are not to scale and the line thickness or the size of components may be exaggerated for clarity. Furthermore, the terms used herein are defined in consideration of the functions of the present disclosure and may be modified according to user or operator requirements. Therefore, the definitions of terms should be consistent with the overall descriptions set forth herein.

[0015] Fig. Figure 1 is a sectional view showing a braking device for vehicles according to an embodiment of the present disclosure. Fig. Figure 2 is a perspective view showing a cylindrical unit according to an embodiment of the present disclosure viewed from one direction. Fig. Figure 3 is a perspective view showing the cylinder unit of Fig. 2 shows it viewed from a different direction. Fig. Figure 4 is a sectional view schematically showing the braking device for vehicles according to an embodiment of the present disclosure. Fig. Figure 5 is a perspective view schematically showing the interior of the cylinder according to an embodiment of the present disclosure. Fig. Figure 6 is a view showing an operating state in which a piston moves forward in the cylinder of the brake device for vehicles according to an embodiment of the present disclosure. Fig. Figure 7 is a view showing an operating state in which the piston in the cylinder of the brake device for vehicles according to an embodiment of the present disclosure moves backwards.

[0016] With reference to Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. 5. A braking device for vehicles according to an embodiment of the present disclosure may comprise a cylinder 200, a motor 300, a screw shaft 400, a nut 500, a piston 600 and a sleeve 700.

[0017] The cylinder 200 can be arranged in a housing 100 and can withstand a torque generated by the formation of hydraulic pressure corresponding to a reciprocating movement of the piston 600. According to one embodiment of the present disclosure, the housing 100 can have a hollow shape with an interior space, and the cylinder 200 can be pressed into the housing 100.

[0018] The housing 100 can be attached to one outside of the cylinder 200 (on the left side based on Fig. 1) be provided. The cylinder 200 can be assembled with the housing 100 under controlled concentricity.

[0019] The cylinder 200 can have a hollow shape. A sleeve 700, in which an actuating section is provided to allow hydraulic pressure to be built up by pressing the piston 600, can be located in a side chamber (on the left side based on Fig. 1) be arranged within the cylinder 200.

[0020] The motor 300 can be connected to the cylinder 200, and various types of drive devices can be used within the framework of a technical teaching to generate torque. The motor 300 can transmit torque to the screw shaft 400.

[0021] The motor 300 can include a stationary component 310, a rotating component 320 and a motor bearing 330.

[0022] The stationary component 310 can be attached to the housing 100 and can be designed in various forms within the framework of a technical teaching in which the magnetic force is changed by supplying current.

[0023] The stationary component 310 can have a mounting frame 311, which is attached to one side of the housing 100 (on a right side based on Fig. 1) is attached, and comprise a stator 312 which is installed on an inner surface of the mounting frame 311 which faces the rotating component 320 and which is configured to generate a magnetic force.

[0024] The mounting frame 311 can be connected to one side of the housing 100. The rotating component 320 can be rotatably installed in the mounting frame 311.

[0025] The stator 312, which is an electromagnet, can be installed in a circumferential direction on an inner surface of the mounting frame 311 and can rotate the rotary component 320 by changing the magnetic flux in response to a control signal from a controller (not shown).

[0026] The rotating component 320 can be connected to the screw shaft 400 and rotate together with the screw shaft 400. Within the framework of a technical teaching in which the rotating component 320 can rotate according to a change in the magnetic force of the stationary component 310, the rotating component 320 can be formed into different shapes.

[0027] The rotating component 320 can be rotatably installed in the mounting frame 311. The rotating component 320 can have an approximately "C"-shaped cross-section and be designed in a hollow form.

[0028] The rotating component 320 can form a rotating frame 321, which is installed in a form that forms one side (the right side based on Fig. 1) of the cylinder 200, and comprise a rotor 322 which is provided on an outer surface of the rotary frame 321 which faces the stationary component 310 and has a magnetic force.

[0029] A splined connection that engages with the screw shaft 400 can be formed in the rotary frame 321, in particular on an inner surface of the rotary frame 321.

[0030] The motor bearing 330 can be provided between the stationary component 310 and the rotating component 320 to reduce the friction generated during the rotation of the rotating component 320. The rotor 322, which is formed from a plurality of magnets installed circumferentially on the rotating frame 321, can rotate together with the rotating frame 321 by changing the magnetic force of the stator 312.

[0031] A frame cover 340 attached to the mounting frame 311 can be installed in a form that encloses an outer surface of one end of the rotating frame 321 to prevent the ingress of foreign substances.

[0032] The screw shaft 400 can be provided in the cylinder 200. The screw shaft 400 can be installed in a longitudinal direction within the cylinder 200 (a left-right direction based on...). Fig. 1) be inserted and axially coupled to the cylinder 200. A central axis of the cylinder 200 and a central axis of the screw shaft 400 can coincide.

[0033] The screw shaft 400 can be attached to a shaft bearing 900 by a support component 1000. The support component 1000 can rotatably mount the screw shaft 400.

[0034] The screw shaft 400 can comprise a screw body 410, a neck section 420, a power transmission section 430 and a coupling section 450.

[0035] The screw body 410 can be rotatably installed in the cylinder 200 and can have a screw thread that extends along a longitudinal direction of the screw shaft 400. The screw body 410 can be arranged in the rotary frame 321 of the motor 300.

[0036] The neck section 420 can extend from an outer surface around a pivot point of the screw body 410 towards a first side (a right side based on Fig. 1) protrudes and can be shaped so that it has a smaller diameter than that of the screw body 410.

[0037] The power transmission section 430 can extend from a free end of the neck section 420 towards the first side (the right side based on Fig. 1) extend and can be shaped so that it has a larger diameter than that of the neck section 420.

[0038] A splined connection can be formed on an outer surface of the power transmission section 430 facing the rotary frame 321 along a circumferential direction. If no shaft cover 440 (which will be described later) is provided, the rotary frame 321 and the power transmission section 430 can accordingly mesh to transmit power.

[0039] The screw shaft 400 can further comprise a shaft cover 440. The shaft cover 440 can be arranged to enclose the neck section 420 and the power transmission section 430. The shaft cover 440 can be arranged between the power transmission section 430 and the rotating frame 321 to prevent metallic rattling noises.

[0040] A splined connection can be formed on an outer surface of the shaft cover 440 along a circumferential direction of the shaft cover 440 and can engage with the rotary frame 321. An outer shape of the shaft cover 440 can correspond to an outer shape of the power transmission section 430.

[0041] A splined connection can be formed along a circumferential direction on an outer surface of the power transmission section 430, which faces the shaft cover 440. Accordingly, the shaft cover 440 and the power transmission section 430 can interlock to transmit power.

[0042] The coupling section 450 can extend from the outer surface around the center of rotation of the screw body 410 to a second side (a left side based on Fig. 1) extend and can be rotatably coupled to the shaft bearing 900. The coupling section 450 can be coupled to the shaft bearing 900 by an interference fit. The coupling section 450 can be designed to have a diameter that is equal to or smaller than that of the screw body 410.

[0043] The nut 500 can be positioned in the rotating frame 321 of the motor 300 and can be arranged in the cylinder 200.

[0044] The nut 500 can be coupled to an outer surface of the screw shaft 400 via a ball B.

[0045] The screw shaft 400 can be coupled to the nut 500. Since the ball B is arranged between a screw thread formed on an inner surface of the nut 500 and the screw thread formed on an outer surface of the screw body 410, a rotary movement of the screw shaft 400 can be converted into a linear movement by the nut 500.

[0046] An anti-rotation projection (not shown) can be formed on an outer surface of the nut 500, and a movement groove (not shown) can be formed on an inner surface of the cylinder 200.

[0047] When the screw shaft 400 rotates, the nut 500 does not rotate because the anti-rotation projection of the nut 500 is blocked by the groove. Accordingly, the rotational movement of the screw shaft 400 can be converted into a linear movement of the nut 500 by the anti-rotation projection and the groove.

[0048] The nut 500 can move back and forth axially along the screw shaft 400 in accordance with the direction of rotation of the screw shaft 400. For example, if the nut 500 moves forward when the screw shaft 400 rotates in a first direction, the nut 500 can move backward when the screw shaft 400 rotates in a second direction opposite to the first.

[0049] The piston 600 can be coupled in such a way that it encloses one outer surface of the nut 500. The piston 600 can move in conjunction with the reciprocating motion of the nut 500 in the longitudinal direction of the cylinder 200.

[0050] The piston 600 can include a rod 610 and a head 620.

[0051] The rod 610 can be hollow and positioned in the rotary frame 321 of the motor 300. The outer surface of the nut 500 and an inner surface of the rod 610 can be threaded together.

[0052] The head 620 can be formed integrally with the rod 610. The outer diameter of the head 620 can be larger than the outer diameter of the rod 610.

[0053] The head 620 can be designed in a ring shape, positioned in the housing 100, and move back and forth in the sleeve 700 to move the working fluid in the sleeve 700 towards the ports 210. Accordingly, the cylinder 200 can build up double-acting hydraulic pressure in accordance with a reciprocating movement of the piston 600.

[0054] The sleeve 700 can be positioned in the housing 100 and can be arranged in the cylinder 200. The sleeve 700 can guide the movement of the piston 600 inserted therein. The sleeve 700 can be shaped to enclose the head 620 of the piston 600.

[0055] The sleeve 700 can be attached at a first end facing the shaft bearing 900 (on a left-hand side based on Fig. 1) closed and at a second end opposite the first end (based on a right side) Fig. 1) be open. The piston 600 can be inserted into the sleeve 700 through the open second end. As the piston 600 moves within the sleeve 700, hydraulic pressure can be built up between the piston 600 and the closed first end of the sleeve 700.

[0056] The ports 210, through which the working fluid flows, can be provided on an outer surface of a region of the cylinder 200 in which the sleeve 700 is arranged. The ports 210 can each be provided at a plurality of points along the longitudinal direction of the cylinder 200.

[0057] The port 210 can comprise a first port 211 and a second port 212, which is arranged such that it is spaced apart from the first port 211 in the direction of the first end of the sleeve 700. The working fluid, which moves according to the movement of the piston 600, can flow through the first port 211 and the second port 212 to build up a required brake pressure.

[0058] The sleeve 700 can be brought into contact with and supported on an inner surface of the cylinder 200 between the first port 211 and the second port 212. Accordingly, any wobble of the sleeve 700 during operation of the vehicle brake device, including during the reciprocating movement of the piston 600, can be suppressed, thus preventing leakage between the sleeve 700 and the cylinder 200.

[0059] The cylinder 200 can have a contact projection 260 on its inner surface. The contact projection 260 can be in surface contact with an outer surface of the sleeve 700 between the first terminal 211 and an area facing the open second end of the sleeve 700.

[0060] The contact projection 260 can be formed along a circumference of the inner surface of the cylinder 200. The contact projection 260 can comprise contact surfaces 261 that are in contact with an outer surface of the sleeve 700, and a guide groove 262 that separates adjacent contact surfaces 261 from one another.

[0061] The guide groove 262 can guide the working fluid within the sleeve 700 to the first connection 211. The guide groove 262 can extend continuously from one end of the contact projection 260 to the other end along a longitudinal direction of the contact projection 260.

[0062] According to the present disclosure, the contact projection 260 can have an end facing the first port 211 and an end opposite it. The guide groove 262 is formed in a recessed groove shape that extends continuously from one end of the contact projection 260 to the other. The working fluid inside the sleeve 700 can thus flow into the guide groove 262 from the other end of the contact projection 260, flow along it, and be discharged from the guide groove 262 at one end of the contact projection 260. The discharged working fluid can exit the sleeve 700 through the first port 211.

[0063] A plurality of guide grooves 262 can be arranged at predetermined intervals in the contact projection 260. Accordingly, the working fluid in the sleeve 700 can move uniformly along these guide grooves 262 in the direction of the first connection 211.

[0064] The guide grooves 262 can be oriented obliquely to a central axis of the cylinder 200. The guide grooves 262 can extend in the longitudinal direction of the cylinder 200 and can be oriented obliquely to the longitudinal direction of the cylinder 200. Accordingly, the sleeve 700 can be in uniform contact with the contact surfaces 261 over its entire outer surface and can be stably supported by the cylinder 200.

[0065] Since the sleeve 700 is supported in surface contact with the contact projection 260 of the cylinder 200 between the area facing the open second end of the sleeve 700 and an area where the first connection 211 is formed, a wobble of the sleeve 700 during the operation of the brake device for vehicles, including during the reciprocating movement of the piston 600, can be suppressed, thereby preventing leakage between the sleeve 700 and the cylinder 200.

[0066] A passage opening 710 connected to the connection 210 can be formed in the outer surface of the sleeve 700.

[0067] A plurality of through-openings 710 can be arranged such that they are spaced apart from one another in a circumferential direction of the sleeve 700. Accordingly, the working fluid can be drained inside the sleeve 700 in the radial direction of the piston 600.

[0068] The braking device for vehicles according to one embodiment of the present disclosure can comprise a shaft bearing 900. The shaft bearing 900 can be arranged in the housing 100 and can be provided at one end in the cylinder 200.

[0069] An outer surface of the shaft bearing 900 and an outer surface of the sleeve 700 can be installed in contact with each other. The shaft bearing 900 can be coupled to the screw shaft 400 in a form that encloses the coupling section 450 of the screw shaft 400.

[0070] The shaft bearing 900 can comprise an inner ring 910, a bearing ball 915, and an outer ring 920. The inner ring 910 can be in contact with the coupling section 450 of the screw shaft 400, and the outer ring 920 can be installed in contact with the inner surface of the cylinder 200.

[0071] The shaft bearing 900 can absorb an axial load during the formation of hydraulic pressure in the cylinder 200 by the piston 600, which moves back and forth in the axial direction of the screw shaft 400.

[0072] The braking device for vehicles according to one embodiment of the present disclosure can include the support component 1000. The support component 1000 can be provided in the cylinder 200. The support component 1000 can be inserted into the coupling section 450 and coupled to the screw shaft 400.

[0073] The support component 1000 can be coupled to the screw shaft 400 by a thread. The shaft bearing 900 can be attached to the support component 1000. The support component 1000 can rotatably support the screw shaft 400. The support component 1000 can be a bolt.

[0074] The braking device for vehicles according to one embodiment of the present disclosure can comprise a reaction force component 1100. A first side of the reaction force component 1100 can be supported by the cylinder 200, and a second side of the reaction force component 1100 can be brought into contact with the sleeve 700 in order to push the sleeve 700 towards the shaft bearing 900. The reaction force component 1100 can be a wave spring.

[0075] An operating procedure of the braking device for vehicles according to an embodiment of the present disclosure with the aforementioned configuration is described below.

[0076] With reference to Fig. 6. When the motor 300 is in operation to transmit a rotational force to the screw shaft 400, the screw shaft 400 can rotate in a first direction of rotation within the cylinder 200 around its axis and the nut 500 can move forward along the screw shaft 400 in the direction of the sleeve 700.

[0077] In response to the movement of the nut 500 towards the sleeve 700, the piston 600 coupled to the nut 500 can move linearly forward in the cylinder 200 in the same direction as the direction of movement of the nut 500, thereby building up hydraulic brake pressure.

[0078] With reference to Fig.7. The nut 500 can move backwards along the screw shaft 400 in a direction opposite to that of the sleeve 700 if the motor 300 operates in such a way that the screw shaft 400 rotates around its axis in the cylinder 200 in a second direction of rotation which is opposite to the first direction of rotation.

[0079] In response to the movement of the nut 500 in the opposite direction to the sleeve 700, the piston 600 connected to the nut 500 can move linearly backwards in the cylinder 200 in the same direction as the direction of movement of the nut 500, thus building up hydraulic brake pressure. Accordingly, a double-acting hydraulic pressure can be built up by the linear forward and backward movement of the piston 600 in the cylinder 200.

[0080] According to the present disclosure, a wobble of the sleeve can be suppressed and thereby a leakage between the sleeve and the cylinder can be prevented.

[0081] Since, according to the present disclosure, a plurality of guide grooves are formed in an inner surface of the cylinder, the working fluid inside the sleeve can move smoothly along the guide grooves.

[0082] Although exemplary embodiments of the disclosure have been disclosed for illustrative purposes, it is apparent to the person skilled in the art that various modifications, additions, and substitutions are possible without departing from the scope of protection and the spirit of the disclosure as defined in the appended claims. The true technical scope of the disclosure should therefore be defined by the following claims. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] KR 10-2021-0064367

[0005]

Claims

[1] Braking device for vehicles, comprising: a cylinder with a first port through which the working fluid moves; a motor designed to generate rotational force; a screw shaft which is arranged in the cylinder and is designed to receive the rotational force from the engine and to rotate axially; a nut that is coupled to the screw shaft and is designed to move back and forth in an axial direction of the screw shaft in response to a rotation of the screw shaft; a shaft bearing that is located in the cylinder and is coupled to the screw shaft; a sleeve arranged between the cylinder and the screw shaft, having a first end that is closed and faces the shaft bearing, and a second end that is open and opposite the first end, the sleeve being in contact with and supported by the cylinder between the first connection and the second end; and a piston that is coupled to the nut and is designed to move back and forth within the sleeve in response to a back-and-forth movement of the nut. [2] Braking device for vehicles according to claim 1, wherein the cylinder further has a second port which is spaced apart from the first port in the direction of the first end of the sleeve, and wherein the sleeve is brought into contact with the cylinder between the first port and the second port and is supported by it. [3] Brake device for vehicles according to claim 1 or 2, wherein the cylinder comprises a contact projection which is in surface contact with an outer surface of the sleeve between the first connection and an area facing the second end. [4] Brake device for vehicles according to claim 3, wherein the contact projection is formed along a circumference of an inner surface of the cylinder. [5] Brake device for vehicles according to claim 4, wherein a guide groove is formed in the contact projection, wherein the guide groove directs the working fluid in the sleeve to the first connection. [6] Brake device for vehicles according to claim 5, wherein the guide groove comprises a plurality of guide grooves arranged in the contact projection at defined intervals. [7] Brake device for vehicles according to claim 6, wherein the guide grooves formed in the contact projection are oriented obliquely to a central axis of the cylinder.

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