Braking device for a vehicle

Abstract

A brake device for a vehicle includes a cylinder including a first port through which a working fluid moves, a motor configured to generate rotational power, a screw shaft located inside the cylinder and configured to receive the rotational power from the motor and axially rotate, a nut coupled to the screw shaft and configured to reciprocate in an axial direction of the screw shaft in response to rotation of the screw shaft, a bearing located inside the cylinder and coupled to the screw shaft, a sleeve located between the cylinder and the screw shaft, including a first end closed and facing the bearing, and a second end open, the sleeve contacting the cylinder and being supported by the cylinder between the first port and the second end, and a piston connected to the nut and configured to reciprocate inside the sleeve in response to reciprocation of the nut. According to the present disclosure, wobble of the sleeve can be inhibited, thereby preventing leakage between the sleeve and the cylinder.

Description

Technical Field

[0001] Exemplary embodiments of this disclosure relate to braking devices for vehicles, and more specifically, to braking devices for vehicles that can convert the rotational motion of a screw shaft generated by the rotational force of an electric motor into the linear motion of a piston. Background Technology

[0002] Typically, due to the characteristics of electric braking devices used in vehicles, a mechanism is required that can convert the rotational motion of an electric motor into the linear motion of a piston within a cylinder to generate hydraulic braking pressure.

[0003] Ball screw devices are used in electric braking systems as mechanisms that convert the rotary motion of a motor into linear motion. A ball screw device includes: a screw shaft that receives rotational force from a motor and rotates about its axis; a nut connected to the screw shaft via balls and configured to move along the axial direction of the screw shaft; and a piston connected to the nut and configured to pressurize working fluid within a cylinder.

[0004] In related technologies, when a piston moves forward and backward to generate hydraulic pressure, if the central axis is tilted excessively, gaps may appear in the sealing structure that generates the hydraulic pressure, leading to leakage problems.

[0005] The background technology disclosed herein has been disclosed in Korean Patent Publication No. 10-2021-0064367 (published on June 2, 2021, entitled "Hydraulic Unit for Hydraulic Vehicle Braking System"). Utility Model Content

[0006] Various embodiments are intended to provide a braking device for a vehicle, wherein leakage between the sleeve and the cylinder is prevented by suppressing sleeve wobble.

[0007] A braking device for a vehicle includes a cylinder having a first port through which a working fluid moves; a motor configured to generate rotational power; a screw shaft located within the cylinder and configured to receive rotational power from the motor and rotate axially; a nut coupled to the screw shaft and configured to reciprocate in the axial direction of the screw shaft in response to rotation of the screw shaft; a bearing located within the cylinder and coupled to the screw shaft; a sleeve located between the cylinder and the screw shaft, including a closed first end facing the bearing and an open second end opposite the first end, the sleeve contacting and being supported by the cylinder between the first port and the second end; and a piston coupled to the nut and configured to reciprocate within the sleeve in response to the reciprocating motion of the nut.

[0008] The cylinder may also include a second port, spaced apart from the first port and facing the first end of the sleeve. Between the first and second ports, the sleeve may contact and be supported by the cylinder.

[0009] The cylinder may include a contact protrusion that makes surface contact with the outer surface of the sleeve between the first port and the region facing the second end.

[0010] Contact protrusions can be formed along the circumference of the inner surface of the cylinder.

[0011] A guide groove can be formed on the contact protrusion, which guides the working fluid inside the sleeve to flow to the first port.

[0012] The guide groove may include multiple guide grooves, which are arranged at fixed intervals on the contact protrusion.

[0013] The multiple guide grooves formed on the contact protrusion can be arranged at an angle relative to the central axis of the cylinder. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view of a braking device for a vehicle according to an embodiment of the present disclosure.

[0015] Figure 2 This is a perspective view of a cylinder unit viewed from one direction, according to an embodiment of the present disclosure.

[0016] Figure 3 yes Figure 2 A three-dimensional view of the cylinder unit shown from another perspective.

[0017] Figure 4 This is a cross-sectional view of a braking device for a vehicle according to an embodiment of the present disclosure.

[0018] Figure 5 This is a perspective view of the interior of a cylinder according to an embodiment of the present disclosure.

[0019] Figure 6 This is an example of an embodiment of the present disclosure showing the operating state of a piston moving forward within a cylinder in a braking device for a vehicle.

[0020] Figure 7 The diagram illustrates the operation of a piston moving rearward within a cylinder in a braking device for a vehicle according to an embodiment of the present disclosure. Detailed Implementation

[0021] Hereinafter, embodiments of the braking device for a vehicle according to the present disclosure will be described with reference to the accompanying drawings. It should be noted that the drawings are not drawn to exact scale, and the thickness of lines or the dimensions of components may be exaggerated for ease of description and clarity only. Furthermore, the terminology used herein is defined with consideration of the function of the present disclosure and may be changed according to the user's or operator's habits or purpose. Therefore, the definitions of terminology should be based on the overall disclosure set forth herein.

[0022] Figure 1 This is a cross-sectional view of a braking device for a vehicle according to an embodiment of the present disclosure. Figure 2 This is a perspective view of a cylinder unit viewed from one direction, according to an embodiment of the present disclosure. Figure 3 yes Figure 2 A three-dimensional view of the cylinder unit shown from another perspective. Figure 4 This is a cross-sectional view of a braking device for a vehicle according to an embodiment of the present disclosure. Figure 5 This is a perspective view of the interior of a cylinder according to an embodiment of the present disclosure. Figure 6 This is an example of an embodiment of the present disclosure showing the operating state of a piston moving forward within a cylinder in a braking device for a vehicle. Figure 7 The diagram illustrates the operating state of a piston moving rearward within a cylinder in a braking device for a vehicle according to an embodiment of the present disclosure.

[0023] refer to Figures 1 to 5 A braking device for a vehicle according to embodiments of the present disclosure may include a cylinder 200, a motor 300, a screw shaft 400, a nut 500, a piston 600, and a sleeve 700.

[0024] The cylinder 200 may be located inside the housing 100 and may withstand the torque generated by the hydraulic pressure created by the reciprocating motion of the piston 600. The housing 100 according to an embodiment of the present disclosure may have a hollow shape, providing an internal space into which the cylinder 200 may be press-fitted.

[0025] The housing 100 can be disposed on the outside of the cylinder 200 (based on...). Figure 1 (Left side). Cylinder 200 can be assembled to housing 100 with controllable concentricity.

[0026] Cylinder 200 may have a hollow shape. Sleeve 700 may be located within one side of the space of cylinder 200 (based on...). Figure 1 (On the left side), an operating section is provided in the sleeve 700 to allow hydraulic pressure to be generated by pressing the piston 600.

[0027] The motor 300 can be connected to the cylinder 200, and various types of drive devices can be used within the technical concept of generating rotational power. The motor 300 can transmit rotational power (torque) to the screw shaft 400.

[0028] The motor 300 may include a stationary component 310, a rotating component 320, and a motor bearing 330.

[0029] The stationary component 310 can be fixed to the housing 100 and can be formed into various shapes within the technical concept of changing the magnetic force by power supply.

[0030] The stationary component 310 may include a component fixed to one side of the housing 100 (based on...). Figure 1 The fixed frame 311 (on the right side) and the stator 312 are mounted on the inner surface of the fixed frame 311 facing the rotating member 320 and are configured to generate magnetic force.

[0031] The fixed frame 311 can be connected to one side of the housing 100. The rotating component 320 can be rotatably mounted inside the fixed frame 311.

[0032] The stator 312 is an electromagnet that can be mounted circumferentially on the inner surface of the fixed frame 311 and can rotate the rotating component 320 by changing the magnetic flux in response to a control signal from a controller (not shown).

[0033] The rotating component 320 can be connected to the screw shaft 400 and can rotate together with the screw shaft 400. The rotating component 320 can be modified into various shapes within the following technical concept: the rotating component 320 can rotate according to the change of the magnetic force of the stationary component 310.

[0034] The rotating component 320 can be rotatably mounted inside the fixed frame 311. The rotating component 320 can have an approximately "C" shaped cross-section and can be formed into a hollow shape.

[0035] Rotating component 320 may include surrounding one side of cylinder 200 (based on...) Figure 1 A rotating frame 321 (on the right side) is mounted in a shape, and a rotor 322 with magnetic force is disposed on the outer surface of the rotating frame 321 facing the stationary member 310.

[0036] A spline that meshes with the screw shaft 400 can be formed in the rotating frame 321, specifically on the inner surface of the rotating frame 321.

[0037] The motor bearing 330 can be disposed between the stationary component 310 and the rotating component 320 to reduce friction generated during the rotation of the rotating component 320. The rotor 322 is composed of a plurality of magnets mounted along the circumferential direction of the rotating frame 321, and the rotor 322 can rotate together with the rotating frame 321 under the action of the magnetic force change of the stator 312.

[0038] A frame cover 340 can be mounted and fixed to a fixed frame 311 in a shape that surrounds the outer surface of the end of the rotating frame 321 to prevent foreign objects from entering.

[0039] The screw shaft 400 can be disposed inside the cylinder 200. The screw shaft 400 can be positioned along the longitudinal direction of the cylinder 200 (based on...). Figure 1 It can be inserted in the left and right directions and can be axially connected to the cylinder 200. The central axis of the cylinder 200 and the central axis of the screw shaft 400 can coincide with each other.

[0040] The screw shaft 400 can be fixed to the bearing 900 by the support member 1000. The support member 1000 can rotatably support the screw shaft 400.

[0041] The screw shaft 400 may include a screw body 410, a neck portion 420, a power transmission portion 430, and a connecting portion 450.

[0042] The screw body 410 can be rotatably mounted within the cylinder 200 and may include a helical thread formed along the longitudinal direction of the screw shaft 400. The screw body 410 may be located inside the rotating frame 321 of the motor 300.

[0043] The neck portion 420 can be oriented from the outer surface of the screw body 410 around the center of rotation towards the first side (based on...). Figure 1 The right side protrudes and can be formed to have a diameter smaller than that of the screw body 410.

[0044] The power transmission section 430 can be directed from the free end of the neck section 420 toward the first side (based on...). Figure 1 (extends to the right) and can be formed with a diameter greater than the diameter of the neck portion 420.

[0045] Splines can be formed along the circumferential direction on the outer surface of the power transmission section 430 facing the rotating frame 321. Therefore, without the shaft cover 440 described below, the rotating frame 321 and the power transmission section 430 can mesh with each other to transmit power.

[0046] The screw shaft 400 may also include a shaft cover 440. The shaft cover 440 may be configured to surround the neck portion 420 and the power transmission portion 430. The shaft cover 440 may be inserted between the power transmission portion 430 and the rotating frame 321 to prevent the generation of metallic rattling noise.

[0047] A spline can be formed on the outer surface of the shaft cover 440 along the circumferential direction, and the spline can engage with the rotating frame 321. The outer shape of the shaft cover 440 can correspond to the outer shape of the power transmission section 430.

[0048] A spline can be formed along the circumferential direction on the outer surface of the power transmission section 430 facing the shaft cover 440. Therefore, the shaft cover 440 and the power transmission section 430 can mesh with each other to transmit power.

[0049] The connecting portion 450 can be directed from the outer surface of the screw body 410 around the center of rotation towards the second side (based on...). Figure 1 The connecting portion 450 extends from the left side and can be rotatably connected to the bearing 900. The connecting portion 450 can also be press-fitted to the bearing 900. The connecting portion 450 can be formed with a diameter equal to or smaller than the diameter of the screw body 410.

[0050] Nut 500 can be located inside the rotating frame 321 of motor 300 and inside cylinder 200.

[0051] Nut 500 can be connected to the outer surface of screw shaft 400 via ball bearing B.

[0052] The screw shaft 400 can be connected by the nut 500. Since the ball B is located between the helical thread formed on the inner surface of the nut 500 and the helical thread formed on the outer surface of the screw body 410, the rotational motion of the screw shaft 400 can be converted into linear motion by the nut 500.

[0053] An anti-rotation protrusion (not shown) may be formed on the outer surface of the nut 500, and a motion groove (not shown) may be formed on the inner surface of the cylinder 200.

[0054] When the screw shaft 400 rotates, the nut 500 does not rotate because the rotation of the anti-rotation protrusion of the nut 500 is blocked by the motion groove. Therefore, the rotational motion of the screw shaft 400 can be converted into the linear motion of the nut 500 through the anti-rotation protrusion and the motion groove.

[0055] The nut 500 can reciprocate along the axial direction of the screw shaft 400 according to the rotation direction of the screw shaft 400. For example, when the screw shaft 400 rotates in a first direction, the nut 500 moves forward, and when the screw shaft 400 rotates in a second direction opposite to the first direction, the nut 500 can move backward.

[0056] The piston 600 can be connected in a manner that surrounds the outside of the nut 500. The piston 600 can move in the longitudinal direction of the cylinder 200 together with the reciprocating motion of the nut 500.

[0057] The piston 600 may include a rod 610 and a head 620.

[0058] The rod 610 can be formed into a hollow shape and can be located inside the rotating frame 321 of the motor 300. The outer surface of the nut 500 and the inner surface of the rod 610 can be threaded together.

[0059] The head 620 can be integrally formed with the rod 610. The outer diameter of the head 620 can be larger than the outer diameter of the rod 610.

[0060] The head 620 can be formed as an annular shape, located inside the housing 100, and can reciprocate inside the sleeve 700 to move the working fluid inside the sleeve 700 toward the port 210. Therefore, the cylinder 200 can generate double-acting hydraulic pressure according to the reciprocating motion of the piston 600.

[0061] The sleeve 700 can be located inside the housing 100 and can be disposed inside the cylinder 200. The sleeve 700 can guide the movement of the piston 600 inserted therein. The sleeve 700 can be formed to surround the head 620 of the piston 600.

[0062] The first end of sleeve 700 facing bearing 900 (based on) Figure 1 The left side of the middle part can be closed, while its second end (based on the first end) opposite the first end can be closed. Figure 1 The right side (of the sleeve) can be open. The piston 600 can be inserted into the sleeve 700 through the open second end of the sleeve 700. As the piston 600 moves within the sleeve 700, hydraulic pressure is created between the piston 600 and the closed first end of the sleeve 700.

[0063] The port 210 through which the working fluid flows can be provided on the outer surface of the area where the sleeve 700 of the cylinder 200 is located. The port 210 can be provided at multiple points along the longitudinal direction of the cylinder 200.

[0064] Port 210 may include a first port 211 and a second port 212, the second port 212 being spaced apart from the first port 211 and facing the first end of the sleeve 700. Working fluid that moves according to the movement of the piston 600 can flow through the first port 211 and the second port 212 to form the required braking pressure.

[0065] Between the first port 211 and the second port 212, the sleeve 700 can contact and be supported by the inner surface of the cylinder 200. Therefore, during the operation of the braking device for the vehicle (including during the reciprocating motion of the piston 600), the wobbling of the sleeve 700 can be suppressed, thereby preventing leakage between the sleeve 700 and the cylinder 200.

[0066] The cylinder 200 may include a contact protrusion 260 on its inner surface. The contact protrusion 260 may make surface contact with the outer surface of the sleeve 700 between the region of the first port 211 and the open second end facing the sleeve 700.

[0067] The contact protrusion 260 may be formed along the circumference of the inner surface of the cylinder 200. The contact protrusion 260 may include a contact surface 261 that contacts the outer surface of the sleeve 700, and a guide groove 262 that separates adjacent contact surfaces 261 from each other.

[0068] The guide groove 262 can guide the working fluid in the sleeve 700 to the first port 211. The guide groove 262 can extend continuously from one end of the contact protrusion 260 to the other end along the longitudinal direction of the contact protrusion 260.

[0069] According to this disclosure, the contact protrusion 260 may include one end oriented toward the first port 211 and another end opposite to that end. The guide groove 262 may be formed in a recessed groove shape and extend continuously from one end of the contact protrusion 260 to the other end. Therefore, working fluid inside the sleeve 700 can flow into the guide groove 262 from the other end side of the contact protrusion 260, flow along the guide groove 262, and exit from the guide groove 262 at one end side of the contact protrusion 260. The discharged working fluid can be discharged to the outside of the sleeve 700 through the first port 211.

[0070] Multiple guide grooves 262 can be provided at predetermined intervals in the contact protrusion 260. Therefore, the working fluid in the sleeve 700 can flow smoothly to the first port 211 along the multiple guide grooves 262.

[0071] The guide groove 262 can be arranged obliquely relative to the central axis of the cylinder 200. The guide groove 262 can extend along the longitudinal direction of the cylinder 200 and can be arranged obliquely relative to the longitudinal direction of the cylinder 200. Therefore, the sleeve 700 can contact the contact surface 261 uniformly on the entire outer surface of the sleeve 700 and can be stably supported by the cylinder 200.

[0072] Since the sleeve 700 is supported in such a way that the contact protrusion 260 with the cylinder 200 makes surface contact between the region of the open second end facing the sleeve 700 and the region where the first through hole 211 is located, the wobbling of the sleeve 700 can be suppressed during the operation of the braking device for the vehicle (including the reciprocating motion of the piston 600), thereby preventing leakage between the sleeve 700 and the cylinder 200.

[0073] A stop hole 710 communicating with port 210 can be formed in the outer surface of sleeve 700.

[0074] Multiple shut-off holes 710 can be provided, which are arranged at intervals along the circumference of the sleeve 700. Therefore, the working fluid inside the sleeve 700 can be discharged in the radial direction of the piston 600.

[0075] A braking device for a vehicle according to an embodiment of the present disclosure may include a bearing 900. The bearing 900 may be located inside a housing 100 and may be disposed at one end inside a cylinder 200.

[0076] The outer surfaces of the bearing 900 and the sleeve 700 can be mounted in contact with each other. The bearing 900 can be connected to the screw shaft 400 in a shape that surrounds the connecting portion 450 of the screw shaft 400.

[0077] The bearing 900 may include an inner ring 910, bearing balls 915, and an outer ring 920. The inner ring 910 may contact the connecting portion 450 of the screw shaft 400, and the outer ring 920 may be mounted in contact with the inner surface of the cylinder 200.

[0078] The bearing 900 can bear the axial load when the piston 600, which reciprocates along the axial direction of the screw shaft 400, generates hydraulic pressure within the cylinder 200.

[0079] A braking device for a vehicle according to an embodiment of the present disclosure may include a support member 1000. The support member 1000 may be disposed inside a cylinder 200. The support member 1000 may be inserted into a connecting portion 450 and may be connected to a screw shaft 400.

[0080] The support member 1000 can be threaded to the screw shaft 400. The bearing 900 can be fixed to the support member 1000. The support member 1000 can rotatably support the screw shaft 400. The support member 1000 can be a bolt.

[0081] A braking device for a vehicle according to an embodiment of the present disclosure may include a reaction force member 1100. A first side of the reaction force member 1100 may be supported by a cylinder 200, and a second side of the reaction force member 1100 may contact a sleeve 700 to press the sleeve 700 against a bearing 900. The reaction force member 1100 may be a wave spring.

[0082] The operation of a braking device for a vehicle having the above configuration according to an embodiment of the present disclosure will now be described.

[0083] refer to Figure 6 When the motor 300 is running and transmits rotational force to the screw shaft 400, the screw shaft 400 can rotate along its axis within the cylinder 200 in a first rotational direction, and the nut 500 can move forward along the screw shaft 400 toward the sleeve 700.

[0084] In response to the movement of the nut 500 toward the sleeve 700, the piston 600 connected to the nut 500 can move linearly forward in the cylinder 200 in the same direction as the movement of the nut 500, thereby generating hydraulic braking pressure.

[0085] refer to Figure 7 When the motor 300 is running, causing the screw shaft 400 to rotate along its axis within the cylinder 200 in a second rotation direction opposite to the first rotation direction, the nut 500 can move backward along the screw shaft 400 in a direction opposite to the sleeve 700.

[0086] In response to the movement of the nut 500 in the opposite direction to that of the sleeve 700, the piston 600 connected to the nut 500 can move linearly backward within the cylinder 200 in the same direction as the movement of the nut 500, thereby generating hydraulic braking pressure. Therefore, when the piston 600 moves linearly forward and backward within the cylinder 200, double-acting hydraulic pressure can be generated.

[0087] According to this disclosure, the swaying of the sleeve can be suppressed, thereby preventing leakage between the sleeve and the cylinder.

[0088] According to this disclosure, since multiple guide grooves are formed in the inner surface of the cylinder, the working fluid in the sleeve can move smoothly along the guide grooves.

[0089] Although this disclosure has been described with reference to embodiments shown in the accompanying drawings, the embodiments of this disclosure are for illustrative purposes only, and those skilled in the art will understand that various modifications and other equivalent embodiments can be made from the described embodiments.

Claims

1. A braking device for a vehicle, characterized in that, include: A cylinder includes a first port through which working fluid moves; The motor is configured to generate rotational power; The screw shaft, located inside the cylinder, is configured to receive rotational power from the motor and rotate axially. A nut is connected to the screw shaft and configured to reciprocate in the axial direction of the screw shaft in response to rotation of the screw shaft; The bearing is located inside the cylinder and is connected to the screw shaft; A sleeve, located between the cylinder and the screw shaft, includes a closed first end facing the bearing and an open second end opposite the first end. Between the first and second ends, the sleeve contacts and is supported by the cylinder. The piston, connected to the nut, is configured to reciprocate within the sleeve in response to the reciprocating motion of the nut.

2. The braking device for a vehicle according to claim 1, characterized in that, The cylinder further includes a second port, which is spaced apart from the first port at the first end of the sleeve. Between the first port and the second port, the sleeve contacts the cylinder and is supported by the cylinder.

3. The braking device for a vehicle according to claim 1, characterized in that, The cylinder includes a contact protrusion that makes surface contact with the outer surface of the sleeve between the first port and the region facing the second end.

4. The braking device for a vehicle according to claim 3, characterized in that, The contact protrusion is formed along the circumference of the inner surface of the cylinder.

5. The braking device for a vehicle according to claim 4, characterized in that, A guide groove is formed on the contact protrusion, and the guide groove guides the working fluid in the sleeve to flow to the first port.

6. The braking device for a vehicle according to claim 5, characterized in that, The guide groove includes multiple guide grooves, which are arranged at fixed intervals on the contact protrusion.

7. The braking device for a vehicle according to claim 6, characterized in that, The plurality of guide grooves formed on the contact protrusion are arranged at an angle relative to the central axis of the cylinder.

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