BRAKE PISTON AND BRAKE SYSTEM WITH THE SAME

Abstract

According to one aspect of the disclosure, a brake piston is provided which is provided in a braking system of a vehicle and presses a brake pad against a disc by means of hydraulic brake pressure, wherein the brake piston comprises: a body section which is installed in a cylinder provided in a brake caliper housing, has the form of a column and is arranged to be able to move forwards and backwards, wherein the body section comprises: a first body section which is provided on an outside of the body section in a radial direction of the disc; and a second body section which is provided on an inside of the body section in the radial direction of the disc and has a coefficient of elasticity which differs from a coefficient of elasticity of the first body section.

Description

1. AREA

[0001] The disclosure relates to a brake piston and a braking system including the same, and more particularly to a brake piston having different properties depending on its parts that must not be rotated during braking, and to a braking system including the brake piston. 2. DESCRIPTION OF THE STATE OF THE ART

[0002] Generally, in a hydraulic braking system, a piston in a cylinder moves forward and backward by hydraulic braking pressure provided by a master cylinder or a hydraulic pressure generator to press a brake pad against a brake disc, and braking force is generated by friction between the brake pad and the brake disc.

[0003] In a floating caliper disc brake system, a piston provided in one side of a caliper housing moves forward and backward to press an inner brake pad, and a finger portion provided in the other side of the caliper housing presses an outer brake pad by a reaction force caused by the pressure.

[0004] At this point, a problem arises: the piston pressing on the brake pad is twisted to one side due to the deformation of the caliper housing and the rotation of the disc in the cylinder. When the piston, which moves forward and backward in the axial direction within the cylinder, is twisted, the piston contacts and damages the inner wall of the cylinder, preventing the brake pad from being properly pressed, resulting in unstable braking.

[0005] Document DE 10 2022 200 960 A1 describes a piston for a brake system, wherein the piston has a first end configured for engagement with a brake fluid and a second end configured for engagement with a brake pad, as well as a piston wall surrounding a cavity of the piston between the first end and the second end. The piston wall consists of a plastic portion. A piston crown is provided at the first end of the piston, which closes off the piston at the first end, wherein the piston crown comprises a metallic portion configured for contact with the brake fluid. Document DE 11 2016 004 881 T5 discloses a brake piston with reduced weight. Document DE 195 34 220 A1 describes a plastic piston with improved thermal conductivity.Document DE 10 2021 103 509 A1 describes a brake piston having a first tubular piston body portion and a second tubular piston body portion, wherein the second piston body portion is connected to the first piston body portion and lies radially completely within the first piston body portion in axial view, forming an annular cavity. DEMOLITION

[0006] One aspect of the disclosure is the provision of a brake piston that has different properties depending on its parts that must not be rotated during braking, and a braking system that includes the brake piston. This object is achieved by a brake piston according to claim 1 and by a braking system according to claim 8.

[0007] Additional aspects of the disclosure will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the disclosure.

[0008] According to one aspect of the disclosure, a brake piston provided in a braking system of a vehicle and pressing a brake pad against a disc by hydraulic braking pressure comprises, in particular, a body portion installed in a cylinder provided in a brake caliper housing, having a column shape, and configured to be movable forward and backward, the body portion comprising: a first body portion provided on an outer side of the body portion in a radial direction of the disc; and a second body portion provided on an inner side of the body portion in the radial direction of the disc and having an elastic coefficient different from an elastic coefficient of the first body portion.

[0009] The first body portion may be connected to the second body portion to form the body portion.

[0010] The first body section and the second body section may be made of different materials.

[0011] The cross-sectional area of ​​the first body portion in an axial direction may differ from the cross-sectional area of ​​the second body portion in the axial direction.

[0012] The elasticity coefficient of the first body portion may be greater than the elasticity coefficient of the second body portion.

[0013] The body portion further comprises a third body portion disposed between the first and second body portions.

[0014] The first body portion and the second body portion may be joined to the third body portion to form the body portion.

[0015] The elasticity coefficient of the third body section differs from the elasticity coefficients of the first body section and the second body section.

[0016] The elasticity coefficient of the first body portion may be greater than the elasticity coefficient of the third body portion, and the elasticity coefficient of the third body portion may be greater than the elasticity coefficient of the second body portion.

[0017] The first body section, the second body section and the third body section may be made of different materials.

[0018] According to one aspect of the disclosure, a brake system specifically includes: a carrier in which a pair of brake pads are installed so as to be movable forward and backward; a caliper housing slidably installed in the carrier, a cylinder provided in the caliper housing; and a piston installed in the cylinder and configured to be movable forward and backward, wherein the piston includes a body portion having a column shape, and the body portion includes: a first body portion provided on an outer side of the body portion in a radial direction of the disc; and a second body portion provided on an inner side of the body portion in the radial direction of the disc and having an elastic coefficient different from an elastic coefficient of the first body portion.

[0019] The first body portion may be connected to the second body portion to form the body portion.

[0020] The first body section and the second body section may be made of different materials.

[0021] The cross-sectional area of ​​the first body portion in an axial direction may differ from the cross-sectional area of ​​the second body portion in the axial direction.

[0022] The elasticity coefficient of the first body portion may be greater than the elasticity coefficient of the second body portion.

[0023] The body portion further comprises a third body portion disposed between the first and second body portions.

[0024] The first body portion and the second body portion may be joined to the third body portion to form the body portion.

[0025] The elasticity coefficient of the third body section differs from the elasticity coefficients of the first body section and the second body section.

[0026] The elasticity coefficient of the first body portion may be greater than the elasticity coefficient of the third body portion, and the elasticity coefficient of the third body portion may be greater than the elasticity coefficient of the second body portion.

[0027] The first body section, the second body section and the third body section may be made of different materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] These and / or other aspects of the disclosure will become clear and better understood from the following description of the embodiments in conjunction with the accompanying drawings: Fig. 1 schematically shows a braking system according to an embodiment of the disclosure; Fig. 2 schematically shows a cross section in the vertical direction of a brake piston according to a first embodiment of the disclosure; Fig. 3 schematically shows a cross section in the horizontal direction AA of the brake piston according to the first embodiment of the disclosure; Fig. 4 schematically shows a cross section in the vertical direction of a brake piston according to a second embodiment of the disclosure; Fig. 5 schematically shows a cross section in the horizontal direction BB of the brake piston according to the second embodiment of the disclosure; Fig. 6 schematically shows a cross-section in the vertical direction of a brake piston according to a third embodiment of the disclosure; and Fig. 7 schematically shows a cross section in the horizontal direction CC of the brake piston according to the third embodiment of the disclosure. DETAILED DESCRIPTION

[0029] Like reference numerals refer to like components throughout the patent application. This patent application does not describe all components of the embodiments, and duplicate content between common contents or embodiments within the technical scope of the present disclosure will be omitted. The terms "part," "module," "element," and "block" used in this specification may be embodied as software or hardware, and it is also possible that a plurality of "parts," "modules," "elements," and "blocks" are embodied as one component, or one "part," "module," "element," and "block" includes a plurality of components according to embodiments.

[0030] When a particular part is “connected” to another part in the application, this includes not only a direct connection but also an indirect connection, and the indirect connection includes the connection via a wireless network.

[0031] Even if a particular part is described as “containing” a component, this means that the component may contain other components, not excluding the other components, unless explicitly stated otherwise.

[0032] The terms “first,” “second,” etc., are used to distinguish one component from another, and the components are not limited by the above terms.

[0033] The singular forms “ein, eine” and “der, die, das” include plural references unless the context clearly requires otherwise.

[0034] For ease of explanation, each operation is given a code number that does not describe the order of the operation, and the operation may be performed in a different order than that given unless the context clearly dictates a particular order.

[0035] Hereinafter, an operating principle and embodiments of the disclosure will be described with reference to the accompanying drawings.

[0036] Fig. 1 schematically shows a braking system according to an embodiment of the disclosure.

[0037] Referring to Fig. 1, a brake system 1 according to the disclosure may include a carrier (not shown) in which a pair of pad plates 110 and 210 are installed so as to be movable forward and backward to press a disc D that rotates together with a wheel (not shown) of a vehicle, a caliper housing 10 slidably installed in the carrier and containing a cylinder 13, and a piston 11 installed in the cylinder 13 so as to be movable forward and backward with respect to the cylinder 13.

[0038] The pair of pad plates 110 and 210 may include an inner pad plate 110 in contact with the piston 11 and an outer pad plate 210 in contact with a finger portion (described below) 12 of the caliper housing 10. The two pad plates 110 and 210 may be installed in the carrier attached to the vehicle body so as to be movable forward and backward toward both side surfaces of the disc D. Furthermore, friction pads 120 and 220 may be attached to the surfaces of the pad plates 110 and 210 facing the disc D, respectively. Thus, the friction pads 120 and 220 may be attached to the pad plates 110 and 210, respectively, to form an inner brake pad 100 and an outer brake pad 200.

[0039] The caliper housing 10 can be slidably installed in the carrier. More specifically, the caliper housing 10 can include the cylinder 13, in which the piston 11 is movable forward and backward, and the finger portion 12, which is formed at a front portion of the caliper housing 10 and bent downward to actuate the outer brake pad 200. The finger portion 12 and the cylinder 13 can be integrated into a single body.

[0040] When hydraulic braking pressure is supplied through an oil port at a rear portion of the caliper housing 10, the piston 11 in the cylinder 13 can press the inner brake pad 100, and the finger portion 12 at the front portion can press the outer brake pad 200 against the disc D. Accordingly, the pair of brake pads 100 and 200 can press the disc D from both sides to perform braking. The braking system 1 is a well-known technology, so a detailed description will be omitted.

[0041] According to one embodiment of the disclosure, the piston 11 may have a body portion in the shape of a column. The body portion may be in the shape of a column and may be installed in the cylinder 13 such that it can be moved forward and backward relative to the cylinder 13. According to one embodiment of the disclosure, a front end of the piston 11, which presses on the brake pad 100, may open.

[0042] A sealing member for preventing oil leakage between an outer peripheral surface of the body portion and an inner surface of the cylinder 13 may be provided on the outer peripheral surface of the body portion. Furthermore, a coupling groove may be provided in the outer peripheral surface of the body portion, into which a boot is inserted to prevent the intrusion of foreign matter between the body portion and the cylinder 13. A clip groove may be provided on an inner side of the open front end of the body portion, to which a coupling clip provided in the brake pad 100 is coupled.

[0043] According to one embodiment of the disclosure, the body portion may comprise a first body portion 15 provided on an outer side of the body portion in a radial direction R of the disk D, and a second body portion 16 provided on an inner side of the body portion in the radial direction R of the disk D. As shown in Fig. 1, the first body portion 15 may be provided on the outer side of the body portion in the radial direction R of the disc D, ie, on an upper side of the braking system 1, and the second body portion 16 may be provided on a lower side of the braking system 1 when the braking system 1 is installed on an upper side of the disc D.

[0044] According to one embodiment of the disclosure, the second body portion 16 may have a coefficient of elasticity that differs from that of the first body portion 15.

[0045] According to one embodiment of the disclosure, the elastic coefficient of the first body portion 15 may be greater than the elastic coefficient of the second body portion 16. That is, when the same load acts on the first body portion 15 and the second body portion 16, the first body portion 15 may be deformed less than the second body portion 16.

[0046] That is, since the piston 11 according to the disclosure has different properties on the outer side of the piston 11 in the radial direction R of the disc D and on the inner side of the piston 11 in the radial direction R of the disc D, a difference can be made between a deformation amount of the first body portion 15 and a deformation amount of the second body portion 16 when the piston 11 presses the brake pad 100 during braking, and the difference in the deformation amount can prevent the piston 11 from being twisted during braking.

[0047] Alternatively, in one embodiment of the disclosure, the second body portion 16 may have a thermal property that differs from that of the first body portion 15. For example, the second body portion 16 may have a different coefficient of thermal expansion than the first body portion 15.

[0048] According to one embodiment of the disclosure, the thermal expansion coefficient of the first body portion 15 may be smaller than the thermal expansion coefficient of the second body portion 16. That is, when the temperature is increased by braking, the first body portion 15 may deform less than the second body portion 16.

[0049] That is, because the piston 11 according to the disclosure has different properties on the outer side of the piston 11 in the radial direction R of the disk D and on the inner side of the piston 11 in the radial direction R of the disk D, a difference can be made between a deformation amount of the first body portion 15 and a deformation amount of the second body portion 16 when the temperature is increased during braking, and the difference in the deformation amount can prevent the piston 11 from being twisted during braking.

[0050] Fig. 2 schematically shows a cross section in the vertical direction of a brake piston according to a first embodiment of the disclosure, and Fig. 3 schematically shows a cross section in the horizontal direction AA of the brake piston according to the first embodiment of the disclosure.

[0051] With reference to the Fig. 2 and Fig. 3, in the brake piston 11 according to the first embodiment of the disclosure, the first body portion 15 may be joined to the second body portion 16 to form the body portion. That is, the first body portion 15 may form one side of the body portion, the second body portion 16 may form another side of the body portion, and the body portion may be formed by joining the first body portion 15 to the second body portion 16.

[0052] As in the Fig. 2 and Fig. As shown in Figure 3, the first body portion 15 may be symmetrical to the second body portion 16. In this case, the first body portion 15 and the second body portion 16 may be made of different materials with different elastic coefficients.

[0053] Thus, in the piston 11 according to the first embodiment of the disclosure, the first body portion 15 and the second body portion 16 can be formed from different materials having different properties, thereby preventing the piston 11 from being twisted during braking.

[0054] The first body portion 15 and the second body portion 16 of the piston 11 may be made of materials such as steel, aluminum, standard gray cast iron, gray cast iron GG150, gray cast iron GG180, SG iron, thermoset or thermoplastic.

[0055] At room temperature (20°C), steel has a modulus of elasticity (E) of 210,000 MPa, a Poisson's ratio of 0.30, and a coefficient of thermal expansion of 1.1*E-05 1 / °K. Aluminum has a modulus of elasticity (E) of 71,000 MPa, a Poisson's ratio of 0.33, and a coefficient of thermal expansion of 2.5*E-05 1 / °K. Standard gray cast iron has a modulus of elasticity (E) of 105,000 MPa, a Poisson's ratio of 0.25, and a coefficient of thermal expansion of 2.2*E-05 1 / °K. Grey cast iron GG150 has a Young's modulus (E) of 100,000 MPa, a Poisson's ratio of 0.25, and a thermal expansion coefficient of 2.2*E-05 1 / °K. Grey cast iron GG180 has a Young's modulus (E) of 110,000 MPa, a Poisson's ratio of 0.24, and a thermal expansion coefficient of 2.3*E-05 1 / °K. SG Iron has a Young's modulus (E) of 165,000 MPa, a Poisson's ratio of 0.28, and a thermal expansion coefficient of 2.3*E-05 1 / °K. Duroplast has a Young's modulus (E) of 5.000 MPa, a Poisson's ratio of 0.38, and a thermal expansion coefficient of 20*E-05 1 / °K. Thermoplastic has a modulus of elasticity (E) of 4,000 MPa, a Poisson's ratio of 0.35, and a thermal expansion coefficient of 25*E-05 1 / °K.

[0056] According to one embodiment of the disclosure, the first body portion 15 may be made of gray cast iron and the second body portion 16 may be made of aluminum, thermoset, or thermoplastic, such that the thermal expansion coefficient of the first body portion 15 may be smaller than the thermal expansion coefficient of the second body portion 16.

[0057] Fig. 4 schematically shows a cross section in the vertical direction of a brake piston according to a second embodiment of the disclosure, and Fig. 5 schematically shows a cross section in the horizontal direction BB of the brake piston according to the second embodiment of the disclosure.

[0058] With reference to the Fig. 4 and Fig. 5, in a brake piston 11 according to the second embodiment of the disclosure, a first body portion 15 and a second body portion 16 may have different cross-sectional areas in the axial direction. As shown in the Fig. 4 and Fig. 5, the thickness t1 of the first body portion 15 in the brake piston 11 whose front end opens may be different from the thickness t2 of the second body portion 16. Due to the difference in thickness, the cross-sectional area in the axial direction of the first body portion 15 may differ from the cross-sectional area in the axial direction of the second body portion 16, as shown in Fig. 5 shown.

[0059] According to the second embodiment of the disclosure, the first body portion 15 and the second body portion 16 may be made of the same material. Since the first body portion 15 and the second body portion 16 have different cross-sectional areas in the axial direction, even though the first body portion 15 and the second body portion 16 are made of the same material, the first body portion 15 and the second body portion 16 may have different deformation characteristics when the first body portion 15 and the second body portion 16 are pressed in the axial direction.

[0060] Alternatively, according to the second embodiment of the disclosure, the first body portion 15 and the second body portion 16 may be made of different materials. The first body portion 15 and the second body portion 16 may have different cross-sectional areas in the axial direction and be made of different materials. When the first body portion 15 and the second body portion 16 are pressed in the axial direction, the first body portion 15 and the second body portion 16 may accordingly have different deformation properties.

[0061] According to the second embodiment of the present disclosure, since the first body portion 15 and the second body portion 16 of the piston 11 have different cross-sectional areas in the axial direction, the first body portion 15 and the second body portion 16 can have different properties, thereby preventing the piston 11 from being twisted during braking.

[0062] Fig. 6 schematically shows a cross section in the vertical direction of a brake piston according to a third embodiment of the disclosure, and Fig. 7 schematically shows a cross section in the horizontal direction CC of the brake piston according to the third embodiment of the disclosure.

[0063] With reference to the Fig. 6 and Fig. 7, in the third embodiment of the disclosure, a brake piston 11 may include, in addition to a first body portion 15 and a second body portion 16, a third body portion 17 disposed between the first body portion 15 and the second body portion 16. In this case, the third body portion 17 may be connected to the first body portion 15 and the second body portion 16 to form one body portion. In this case, the first body portion 15 may be connected to the third body portion 17, and the second body portion 16 may be connected to the third body portion 17.That is, the third body portion 17 may form a middle portion of the body portion, the first body portion 15 may form one side of the body portion, the second body portion 16 may form another side of the body portion, and accordingly, the first body portion 15 and the second body portion 16 may be joined to the third body portion 17 to thereby form the body portion.

[0064] As in the Fig. 6 and Fig. As shown in Figure 7, the first body portion 15 may be symmetrical to the second body portion 16. In this case, the first body portion 15 and the second body portion 16 may be made of different materials with different elastic coefficients.

[0065] Also, the third body portion 17 may have a different elasticity coefficient than the first body portion 15 and the second body portion 16. That is, the first body portion 15, the second body portion 16 and the third body portion 17 may have different elasticity coefficients.

[0066] According to one embodiment of the disclosure, the first body portion 15, the second body portion 16, and the third body portion 17 of the piston 11 may be made of materials such as steel, aluminum, standard gray cast iron, gray cast iron GG150, gray cast iron GG180, SG iron, thermoset, or thermoplastic.

[0067] According to one embodiment of the disclosure, the elastic coefficient of the first body portion 15 may be greater than the elastic coefficient of the third body portion 17, and the elastic coefficient of the third body portion 17 may be greater than the elastic coefficient of the second body portion 16. When the same load acts on the third body portion 15, the second body portion 16, and the third body portion 17, the first body portion 15 may be deformed less than the third body portion 17, and the third body portion 17 may be deformed less than the second body portion 16.

[0068] That is, because the piston 11 according to the disclosure has different properties on the outer side in the radial direction R of the disc D and on the inner side in the radial direction of the disc D, the first body portion 15, the third body portion 17, and the second body portion 16 can be deformed by different amounts of deformation when the piston 11 presses the brake pad 100 during braking, and the difference in the amount of deformation can prevent the piston 11 from being twisted during braking.

[0069] In this case, the first body portion 15, the second body portion 16 and the third body portion 17 may be made of different materials with different elastic coefficients.

[0070] Thus, according to the third embodiment of the disclosure, the first body portion 15, the second body portion 16, and the third body portion 17 of the piston 11 can be made of different materials to have different properties, and accordingly, the piston 11 can be prevented from being twisted during braking.

[0071] In the brake piston and the brake system according to an embodiment of the disclosure, the brake piston can be prevented from being twisted during braking.

Claims

[1] Brake piston (11) provided in a braking system (1) of a vehicle and pressing a brake pad (100) against a disc (D) by hydraulic braking pressure, the brake piston (11) comprising: a body portion installed in a cylinder (13) provided in a brake caliper housing (10), having the shape of a column and adapted to be moved forward and backward, wherein the body section comprises: a first body portion (15) forming an outer part of the body portion in the radial direction of the disc (D) when the brake piston is installed in the brake system (1); a second body portion (16) forming an inner part of the body portion in the radial direction of the disc (D) when the brake piston (11) is installed in the brake system (1), and having a coefficient of elasticity different from a coefficient of elasticity of the first body portion (15); and a third body portion (17) arranged between the first body portion (15) and the second body portion (16), wherein the elasticity coefficient of the third body portion (17) differs from the elasticity coefficients of the first body portion (15) and the second body portion (16). [2] Brake piston (11) according to claim 1, wherein the first body portion (15) and the second body portion (16) are made of different materials. [3] Brake piston (11) according to one of claims 1 or 2, wherein a cross-sectional area of ​​the first body portion (15) in an axial direction is different from a cross-sectional area of ​​the second body portion (16) in the axial direction. [4] Brake piston (11) according to one of claims 1 to 3, wherein the elasticity coefficient of the first body portion (15) is greater than the elasticity coefficient of the second body portion (16). [5] Brake piston (11) according to one of claims 1 to 4, wherein the first body portion (15) and the second body portion (16) are connected to the third body portion (17) to form the body portion. [6] Brake piston (11) according to one of claims 1 to 5, wherein the elasticity coefficient of the first body portion (15) is greater than the elasticity coefficient of the third body portion (17), and the elasticity coefficient of the third body portion (17) is greater than the elasticity coefficient of the second body portion (16). [7] Brake piston (11) according to one of claims 1 to 6, wherein the first body portion (15), the second body portion (16) and the third body portion (17) are made of different materials. [8] Braking system (1), comprising: a carrier in which a pair of brake pads (100, 200) are installed to be movable forward and backward; a brake caliper housing (10) slidably installed in the carrier, wherein a cylinder (13) is provided in the brake caliper housing (10); and a piston (11) installed in the cylinder (13) and arranged to be moved forwards and backwards to press one of the brake pads (100) against a disc (D), wherein the piston (11) has a body portion in the form of a column, and the body section includes: a first body portion (15) forming an outer part of the body portion in the radial direction of the disc (D); and a second body portion (16) forming an inner part of the body portion in the radial direction of the disc (D) and having a coefficient of elasticity different from a coefficient of elasticity of the first body portion (15); and a third body portion (17) arranged between the first body portion (15) and the second body portion (16), wherein the elasticity coefficient of the third body portion (17) differs from the elasticity coefficients of the first body portion (15) and the second body portion (16). [9] Braking system (1) according to claim 8, wherein the first body portion (15) and the second body portion (16) are made of different materials. [10] A braking system (1) according to any one of claims 8 or 9, wherein a cross-sectional area of ​​the first body portion (15) in an axial direction is different from a cross-sectional area of ​​the second body portion (16) in the axial direction. [11] Braking system (1) according to one of claims 8 to 10, wherein the elasticity coefficient of the first body portion (15) is greater than the elasticity coefficient of the second body portion (16). [12] Braking system (1) according to one of claims 8 to 11, wherein the first body portion (15) and the second body portion (16) are connected to the third body portion (17) to form the body portion. [13] Braking system (1) according to one of claims 8 to 12, wherein the elasticity coefficient of the first body portion (15) is greater than the elasticity coefficient of the third body portion (17), and the elasticity coefficient of the third body portion (17) is greater than the elasticity coefficient of the second body portion (16). [14] Braking system (1) according to one of claims 8 to 13, wherein the first body portion (15), the second body portion (16) and the third body portion (17) are made of different materials.

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