Piston and integral electronic hydraulic braking system

Abstract

The utility model discloses a piston and an integral electronic hydraulic brake system, and the piston comprises a base part serving as the peripheral part of a piston main body, a plastic jacket which is wrapped and formed on the peripheral surface of the base part, and a limiting part which is arranged between the base part and the plastic jacket, the limiting part comprises an axial limiting structure and a circumferential limiting structure, the axial limiting structure is arranged on the base part, packaged in the plastic outer sleeve in an embedded mode and used for preventing the plastic outer sleeve from moving in the relative axial direction, the circumferential limiting structure is used for preventing the plastic outer sleeve from rotating in the relative circumferential direction, the axial limiting structure comprises an annular groove formed in the base part, and the circumferential limiting structure is formed in or outside the annular groove. The integral electronic hydraulic brake system comprises a cylinder body and the piston matched with the cylinder body. According to the brand-new piston structure, hard oxidation on the surface of an original piston can be eliminated, the structure is achieved mainly through injection molding of the wear-resistant plastic on the piston base part, hard oxidation on the surface of the piston can be replaced, and the cost of parts is reduced.

Description

Technical Field

[0001] This utility model relates to piston technology for brakes, and more specifically to a piston and an integrated electro-hydraulic braking system. Background Technology

[0002] In the context of intelligent and electric vehicles, traditional internal combustion engines are being replaced by electric motors and batteries. This results in a lack of a vacuum source in the vehicle, making it impossible to build up pressure in the hydraulic lines using a vacuum booster. Vacuum booster pumps, due to their high noise levels and short lifespan, have not been widely adopted. Brake-by-wire, by using an electric motor instead of a vacuum booster to build up pressure in the brake hydraulic lines, effectively solves the problem of a lack of vacuum source.

[0003] Depending on the implementation method of the brake-by-wire system in passenger vehicles, brake-by-wire systems can currently be divided into two categories: EHB (Electro-hydraulic Braking System) and EMB (Electro-mechanical Braking System).

[0004] EHB (Electronic Braking System) is based on the traditional hydraulic braking system, replacing some of the functions of mechanical components with electronic devices. It uses brake fluid as the power transmission medium and also features a hydraulic backup braking system, making it the mainstream technology solution currently available. Based on the level of integration, EHB is further divided into two types: split-type and integrated-type.

[0005] One of the integral parts is the piston, which mainly cooperates with the cylinder block for pressure reduction in the product. For example... Figures 4-7 As shown, the integrated analog cylinder primarily serves as a mechanical backup and receives driver input. During operation, the pedal push rod 21 pushes the first-chamber piston 22 forward, compressing the brake fluid within the brake chamber. Simultaneously, due to the sealing effect of the piston cups (corresponding to the main piston cup 24 and the auxiliary piston cup 23), hydraulic pressure is generated within the brake chamber. The second chamber operates on the same principle as the first chamber. Because the first and second chambers are connected in series, the thrust of the second chamber is transmitted from the first chamber. Throughout the entire lifecycle of the integrated product, these movements are repeated millions of times. The following problems exist:

[0006] 1) During the movement of the piston (corresponding to the first-chamber piston 22 and the second-chamber piston 26), the piston cup and the piston are always in an interference seal state. If the force between the piston and the piston cup is uneven, uneven wear will occur, which will accelerate the wear of the piston cup and reduce its service life.

[0007] 2) To prevent uneven wear between the piston and the piston cup, one or two support structures 27 are added to the valve block 25 and the cylinder cavity. Thus, at the support structure 27, the gap between the piston and the inner wall of the cylinder (inner wall of the valve block 25) is small, supporting the piston during movement and preventing uneven wear. However, because the gap between the piston and the valve block 25 at the support structure 27 is small, and the piston cup is made of rubber, which is compressible, contact friction easily occurs between the piston and the support structure 27 of the valve block 25 during movement. This leads to wear on the piston surface and the inner wall of the valve block 25, which in turn damages the piston cup, affecting product performance.

[0008] 3) To prevent wear between the valve block 25 and the piston due to friction, the common solution is to perform hard anodizing on the piston and valve block 25 to increase the surface hardness and wear resistance of the parts and prevent wear. However, hard anodizing itself is very expensive. For the piston, only the contact friction point with the valve block 25 support structure 27, i.e., the outer circle of the piston, needs hard anodizing. However, during the production process, it is not possible to perform hard anodizing on individual parts of the parts; the entire part needs to be hard anodized, which greatly increases the cost of the parts. Utility Model Content

[0009] To address the aforementioned problems, the purpose of this utility model is to provide a piston-integrated electro-hydraulic braking system.

[0010] According to one aspect of the present invention, a piston is provided, comprising: a base as the outer periphery of the piston body, a plastic jacket formed on the outer periphery of the base, and a limiting portion between the base and the plastic jacket, wherein the limiting portion includes an axial limiting structure disposed on the base and encapsulated in the plastic jacket in an fitted manner to prevent the plastic jacket from moving relative to the axial direction and a circumferential limiting structure for rotating relative to the circumferential direction, the axial limiting structure including an annular groove formed in the base, and the circumferential limiting structure formed in or outside the annular groove.

[0011] Preferably, the plastic jacket is injection molded from wear-resistant plastic onto the outer peripheral surface of the base, serving as the outer wall of the piston that mates with the simulated cylinder or main cylinder body.

[0012] Preferably, the limiting part is formed by any one or a combination of splines, straight lines, grooves, and holes.

[0013] Preferably, a cylindrical hole with a diameter larger than the width of the annular groove is provided at a predetermined position in the circumferential direction of the annular groove.

[0014] Preferably, the cylindrical hole is formed as a stepped hole.

[0015] Preferably, a cross groove intersecting the annular groove is provided at a predetermined position in the circumferential direction of the annular groove.

[0016] Preferably, the annular groove is formed on the end side of the piston or in a solid structural part of its cross-section.

[0017] According to another aspect of the present invention, an integrated electro-hydraulic braking system is provided, including a cylinder and a piston that cooperates with the cylinder, wherein the piston is the piston described above.

[0018] The novel piston structure proposed in this invention eliminates the hard anodizing of the original piston surface. It is mainly achieved by injection molding wear-resistant plastic onto the bottom of the piston base, which can replace the hard anodizing of the piston surface and reduce the cost of the parts. Attached Figure Description

[0019] Figure 1 A schematic cross-sectional view of a piston for a braking system according to an embodiment of the present invention is shown.

[0020] Figure 2 An isometric view of the piston is shown schematically.

[0021] Figure 3 A schematic side view of the piston is shown.

[0022] Figure 4 A schematic cross-sectional view of an existing integrated electromechanical braking system is shown.

[0023] Figure 5 The arrangement of the support structure for an existing integral piston is shown schematically.

[0024] Figure 6 A schematic cross-sectional view of an existing integral piston is shown.

[0025] Figure 7 A schematic isometric view of an existing integral piston is shown. Detailed Implementation

[0026] The exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The exemplary embodiments described below and illustrated in the drawings are intended to teach the principles of the present invention, enabling those skilled in the art to implement and use the present invention in various environments and for various applications. Therefore, the scope of protection of the present invention is defined by the appended claims, and the exemplary embodiments are not intended, and should not be considered, a limiting description of the scope of protection of the present invention. Furthermore, for ease of description, the dimensions of the various parts shown in the drawings are not necessarily drawn to actual scale. Orientation descriptions, such as circumferential, up, down, left, right, top, bottom, etc., relative to the axial direction, are based on the orientation or positional relationships shown in the drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or partial constructions will be omitted where they may cause confusion or make the understanding of the present disclosure difficult to observe. Unless otherwise specifically stated, the order and numerical values ​​of the components and assembly steps described in the embodiments do not limit the scope of this invention.

[0027] Since the piston of this utility model has many applications, this utility model will only describe one type of piston used in brakes as an exemplary embodiment.

[0028] like Figures 1-3 As shown, the piston 1 includes an aluminum base 2 forming the outer periphery of the piston 1 body, and a wear-resistant plastic sleeve 3 injection-molded onto the outer periphery of the base 2. This plastic sleeve 3 forms the outer wall that mates with the cylinder, replacing traditional hard anodizing and thus applicable to pistons requiring wear resistance on various outer surfaces. In this way, the piston structure utilizes the wear-resistant plastic material wrapped around the outer wall of the aluminum base 2, eliminating the need for hard anodizing to improve the surface hardness and wear resistance (i.e., the outer wall of the base 2). The position and thickness of the plastic sleeve 3 can be determined according to actual needs.

[0029] Accordingly, for cylinders of the same specifications (simulated cylinder or main cylinder), the outer diameter of the base 2 is smaller than the original piston outer diameter (corresponding to the design outer diameter). After the plastic outer sleeve 3 is injection molded, the overall outer diameter is the same as the original piston diameter. Therefore, the piston structure proposed in this invention can be applied to pistons of different specifications.

[0030] On the base 2, there are axial limiting structures 4 to prevent axial movement and circumferential limiting structures 5 to prevent circumferential rotation as limiting parts, which are encapsulated in the plastic jacket 3 in a fitting (also known as interlocking or engagement) manner. This is to prevent relative movement between the plastic jacket 3 and the base 2 during the operation of the piston 1, so as to avoid affecting the performance of the parts.

[0031] In some embodiments, the base 2 of the piston 1 has an axial limiting structure 4 and a circumferential limiting structure 5, which can be any one of splines, straight grooves, slots, holes, or combinations thereof, etc., that have a limiting function. Splines can protrude from keyways through mating to form axial and circumferential limiting structures, while straight grooves can form circumferential limiting structures by creating circumferentially spaced, straight, shallow grooves. Here, straight grooves are often used in parallel as multiple grooves, thus distinguishing them from slots, which are often used alone.

[0032] Specifically, such as Figure 2 In the middle, an axial limiting structure in the form of annular groove 6 can be used to restrict the axial movement between the plastic jacket 3 and the base 2.

[0033] like Figure 3 In the process, a cylindrical hole 7, larger than the width of the annular groove 6, is provided at a predetermined position in the circumferential direction of the annular groove 6. After injection molding, since the inner diameter of the cylindrical hole 7 is larger than the width of the annular groove 6, it can prevent the plastic jacket 3 from rotating axially with the base 2. Of course, it is not limited to a cylindrical hole; other shapes of grooves and holes can also be used, such as intersecting grooves that intersect with the annular groove 6, or stepped holes.

[0034] Alternatively, a structure with straight lines 8 machined in the annular groove 6 can be used as a circumferential limit to restrict the relative rotation between the plastic jacket 3 and the base 2.

[0035] Alternatively, a spline (not shown) larger than the annular groove 6 can be used for axial and circumferential limiting.

[0036] Here, the annular groove 6 is preferably formed on the end side of the piston 1 or in a solid structural portion of its cross-section. The circumferential limiting structure is formed in or outside the annular groove.

[0037] Thus, the base 2 can be of a certain length according to the stroke design requirements, and the outer wall that contacts the inner wall of the cylinder will be completely covered by the plastic sleeve 3. The outer diameter and roughness of the plastic sleeve 3 should meet the piston design requirements.

[0038] As described above, according to this utility model, by pre-setting the limiting structure and then injection molding it into a single unit, the hard anodizing of the piston surface is eliminated, thus removing the cost of hard anodizing of the parts; correspondingly, no new cutting tools are needed, reducing tooling costs; replacing the friction between the metal piston and the valve block, by using wear-resistant plastic to rub against the valve block, the noise generated by the friction between the piston and the cylinder can be reduced, which is especially suitable for current automobiles and other products where there are high requirements for both overall vehicle cost and noise reduction. The piston base and the piston outer wall should have good sealing performance; preferably, the plastic outer wall should have good roughness.

[0039] In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified. Unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Although the present invention has been described with reference to various specific embodiments, it should be understood that modifications can be made within the spirit and scope of the described inventive concept. Therefore, it is intended that the present invention be limited to the described embodiments but will have the full scope defined by the language of the appended claims.

Claims

1. A piston, characterized in that, include: The piston body consists of a base (2) on its outer periphery, a plastic jacket (3) formed around the outer periphery of the base (2), and a limiting part between the base (2) and the plastic jacket (3). The limiting part includes an axial limiting structure (4) provided on the base (2) and encapsulated in the plastic jacket (3) in an interlocking manner to prevent the plastic jacket (3) from moving relative to the axial direction, and a circumferential limiting structure (5) for relative circumferential rotation. The axial limiting structure (4) includes an annular groove (6) formed on the base (2), and the circumferential limiting structure (5) is formed in or outside the annular groove (6).

2. The piston according to claim 1, characterized in that, The plastic jacket (3) is injection molded from wear-resistant plastic onto the outer circumferential surface of the base (2) and serves as the outer wall of the piston (1) that mates with the simulated cylinder or main cylinder.

3. The piston according to claim 1, characterized in that, The limiting part is selected from any one or a combination of splines, straight lines, grooves, and holes.

4. The piston according to claim 1, characterized in that, A cylindrical hole (7) with a diameter larger than the width of the annular groove (6) is provided at a predetermined position in the circumferential direction of the annular groove (6).

5. The piston according to claim 1, characterized in that, The cylindrical hole (7) is formed as a stepped hole.

6. The piston according to claim 1, characterized in that, At a predetermined position in the circumferential direction of the annular groove (6), there is a cross groove that intersects with the annular groove (6).

7. The piston according to claim 1, characterized in that, The annular groove (6) is formed on the end side or in the solid structural part of the cross section of the piston (1).

8. An integrated electro-hydraulic braking system, comprising a cylinder and a piston cooperating with the cylinder, characterized in that, The piston is the piston according to any one of claims 1 to 1.

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