Split press-fitting type aluminum piston

Abstract

The utility model discloses a split press-fitting type aluminum piston, and belongs to the technical field of automobile braking. The piston comprises a steel piston head and an aluminum piston body, an installation hole is formed in the piston body, one end of the piston head is installed in the installation hole through interference fit of an outer spline and an inner spline, and an open groove is formed in the other end of the piston head to limit displacement of a brake shoe. Six petal structures evenly distributed circumferentially are designed at the end, away from the piston head, of the piston body, and flowing of brake fluid is facilitated. The steel piston head is used for bearing high load, the aluminum body reduces abrasion of a cylinder hole and achieves light weight, and spline connection ensures bonding strength. Compared with a traditional piston, the piston is light in weight, long in service life, high in braking efficiency and suitable for a modern automobile braking system.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of automobile brake technology relates to a split press -fit type aluminum piston. BACKGROUND

[0002] With the rapid development of automobile industry, the light weight design of automobile has become an important trend of industry development. Light weight design not only helps to reduce the weight of the vehicle, improve fuel economy, but also can reduce emissions, meet the requirements of energy saving and environmental protection. At the same time, with the increasing attention of consumers to the reliability and durability of the automobile, the state's requirements for the automobile "three guarantees" policy are also constantly tightened, which puts forward higher standards for the service life and performance of automobile parts. In the automobile brake system, the piston as the key component of brake master cylinder directly affects the braking effect and the long-term stability of the system. The traditional piston is mostly made of steel material, although the steel piston has certain advantages in strength and wear resistance, but its weight is larger, which is contrary to the modern light weight design concept. In addition, the steel piston is easy to cause the wear of the cylinder hole wall to aggravate when in long-term contact and friction with the brake master cylinder body, thereby shortening the service life of the cylinder body and increasing the maintenance cost.

[0003] Compared with the steel piston, the aluminum piston gradually attracts attention due to its light weight, good corrosion resistance and other characteristics. The density of aluminum material is much lower than that of steel material, and the use of aluminum piston can significantly reduce the mass of the piston component in the brake system, thereby reducing the weight of the vehicle and improving the controllability and energy efficiency of the vehicle. At the same time, the friction coefficient of aluminum material is relatively low when in contact with the cylinder body, which can effectively reduce the wear of the cylinder hole and prolong the service life of the brake master cylinder. However, the aluminum piston also has obvious shortcomings. Since the strength and hardness of aluminum material are lower than those of steel material, the overall aluminum piston is easy to deform or even break when subjected to high strength force applied by the brake shoe, which cannot meet the stringent requirements of the brake system on the strength of the piston. This contradiction makes it difficult for the piston design of single material to simultaneously meet the requirements of light weight and high strength.

[0004] To solve this problem, the industry has begun to explore the design ideas of composite pistons, that is, by splitting the piston into combined components of different materials, the advantages of various materials can be fully utilized. For example, the piston head is designed as a steel structure to withstand the high load of the brake shoe, and the piston body is made of aluminum to achieve lightweight and reduce cylinder wear. However, the existing split piston design still faces some technical challenges in practical application. For example, the connection method of the steel head and the aluminum body needs to ensure sufficient strength and stability, otherwise it is easy to loosen or fail under high-frequency vibration or complex working conditions. In addition, the internal structure design of the piston also needs to consider the flow performance of the brake fluid to ensure the response speed and efficiency of the brake system. Traditional connection methods such as welding or threaded connection, while achieving split design to some extent, the welding process is complex and may introduce defects in the heat-affected zone, and threaded connection increases the processing difficulty and assembly time, which is not conducive to mass production. Practical new type content

[0005] Therefore, the purpose of the present application is to provide a split press-fit aluminum piston, which overcomes the shortcomings of traditional piston design through innovative structure design and connection method.

[0006] To achieve the above purpose, the present application provides the following technical solutions:

[0007] A split press-fit aluminum piston, comprising a steel piston head and an aluminum piston body; the piston body is provided with a mounting hole, one end of the piston head is installed in the mounting hole with interference, and the other end of the piston head is provided with an open slot for limiting the displacement of the brake shoe.

[0008] Further, the end of the piston body away from the piston head is provided with a petal structure, which facilitates the flow of brake fluid.

[0009] Further, the petal structure is six petal structures uniformly distributed around the circumference.

[0010] Further, the piston head is provided with an external spline, the mounting hole is provided with an internal spline, and the piston head and the piston body are connected and fixed by interference fit of the external spline and the internal spline.

[0011] Further, the open slot is a through slot arranged radially along the piston head.

[0012] The beneficial effects of the present application are as follows:

[0013] The utility model discloses a split press -pack design of steel piston head and aluminum piston body, and the connecting mode of keyway interference fit is combined, so that the steel piston head can bear the larger load that brake shoe exerts, and the aluminum piston body contacts with wheel cylinder hole, which significantly reduces the wear of cylinder hole and prolongs the service life of brake master cylinder. In addition, the application of aluminum piston body reduces the overall weight of the piston, which meets the requirements of automobile lightweight design. The petal structure at the end of the piston body further optimizes the flow performance of brake fluid and improves the response efficiency of the brake system. The design has simple structure, convenient assembly, high practical value and wide application prospect.

[0014] Other advantages, objects, and features of the present utility model will be in part apparent and in part pointed out hereinafter based on the accompanying drawings and detailed description, and will be the best understood by those skilled in the art when the present utility model is read in light of the following detailed description. The objects and other advantages of the present utility model can be realized and obtained by the following description. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to make the purpose, technical scheme and advantages of the utility model more clear, the preferred detailed description of the utility model will be combined with the drawings below, wherein:

[0016] Figure 1 It is the explosion map of the split press -pack type aluminum piston in the embodiment of the utility model.

[0017] Figure 2 It is Figure 1 It is the orthographic projection of the explosion map.

[0018] Figure 3 It is the assembly state diagram of the split press -pack type aluminum piston in the embodiment of the utility model.

[0019] Reference signs: 1-piston head;2-piston body;3-opening groove;4-outer key;5-petal structure. DETAILED DESCRIPTION

[0020] The embodiments of the present utility model will be described below through specific concrete examples, and those skilled in the art can easily understand other advantages and effects of the present utility model from the contents disclosed in the present specification. The present utility model can also be implemented or applied through other different concrete embodiments, and each detail in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present utility model. It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present utility model in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0021] Among them, the drawings are only used for example, the representation is only a schematic diagram, and not a physical diagram, and cannot be understood as a limitation on the utility model; in order to better illustrate the embodiments of the utility model, some components of the drawings will be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures in the drawings and their descriptions can be omitted.

[0022] The same or similar reference numerals in the drawings of the embodiments of the utility model correspond to the same or similar components; in the description of the utility model, it is understood that if the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear" and the like is based on the orientation or positional relationship shown in the drawings, it is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the positional relationship described in the drawings is only used for example, and cannot be understood as a limitation on the utility model, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0023] Please refer to Figures 1 to 3 It is a split press-fit type aluminum piston, which mainly comprises a steel piston head 1 and an aluminum piston body 2, and realizes function optimization through specific connection mode and structure design.

[0024] Specifically, the piston body 2 is made of aluminum alloy material, which has low density and good corrosion resistance, and has an installation hole processed inside, which is used for assembly connection with the piston head 1. The piston head 1 is made of low carbon steel material, which has high strength and wear resistance, and can withstand the large force applied by the brake shoe. The manufacturing process of the piston head 1 is as follows: first, the low carbon steel blank is processed by cold heading process to make the basic shape of the piston head 1, and the cold heading process can improve the density and strength of the material, laying a foundation for subsequent processing. Secondly, an external spline 4 is processed on one end of the piston head 1 by hobbing process, which is matched with the internal spline on the inner wall of the installation hole of the piston body 2. The spline processed by hobbing process has high precision and surface quality, which ensures the stability of the subsequent press fitting. Thirdly, an open slot 3 is processed on the other end of the piston head 1 using a milling cutter, which is a through slot structure arranged along the radial direction of the piston head 1, which cooperates with the brake shoe to limit the displacement of the brake shoe, and ensures the action accuracy and stability of the brake system. In this embodiment, the width of the open slot 3 is 5mm, and the depth is 8mm, which is suitable for common brake shoe specifications.

[0025] The inner wall of the mounting hole of the piston body 2 is processed with internal splines corresponding to the external splines 4 of the piston head 1. During assembly, the external splines 4 of the piston head 1 are aligned with the mounting hole of the piston body 2, and the external splines 4 are made to fit with the internal splines by applying a constant pressure, so as to press the piston head 1 into the piston body 2 and form a firm connection. This spline interference fit not only ensures the strength and stability of the connection, but also avoids the complexity and potential defects of traditional welding or threaded connection, ensuring the reliability of the piston under high-frequency vibration or complex working conditions.

[0026] The end of the piston body 2 away from the piston head 1 is designed with a petal structure 5 composed of six petals evenly distributed along the circumference. Each petal is arc-shaped with a thickness of about 2 mm, and the gap between adjacent petals is about 3 mm. The design of this petal structure 5 increases the opening area of the end of the piston body 2, facilitating the smooth flow of brake fluid between the piston and the brake master cylinder, thereby improving the response speed and heat dissipation performance of the brake system. In actual assembly, the piston body 2 is in direct contact with the brake fluid through this end, and the petal structure 5 effectively reduces the resistance of the brake fluid flow, improving the braking efficiency.

[0027] In this embodiment, the complete manufacturing and assembly process of the split press-fitted aluminum piston is as follows: First, the basic shape of the piston head 1 is made through cold heading process; second, the external splines 4 are machined on the piston head 1 using gear hobbing process; third, the open slot 3 is machined using a milling cutter, completing the shaping of the piston head 1; at the same time, the piston body 2 is made through aluminum alloy casting or extrusion process, and internal splines are machined in the mounting hole; finally, the piston head 1 is pressed into the mounting hole of the piston body 2 using a special press-fitting equipment, completing the assembly of the two. After press-fitting, the coaxiality and connection strength of the piston head 1 and the piston body 2 are checked to ensure that there is no looseness or deviation. Subsequently, the assembled piston is installed into the brake master cylinder, with the open slot 3 of the piston head 1 aligned with the brake shoes and the petal structure 5 of the piston body 2 facing the brake fluid inlet direction. After installation, the sealing performance and braking performance are tested to verify the working effect.

[0028] The advantage of this embodiment is that the steel piston head 1 can effectively withstand the high load of the brake shoes, while the aluminum piston body 2 has a lower friction coefficient when in contact with the cylinder hole, significantly reducing the wear of the cylinder hole and prolonging the service life of the brake master cylinder. At the same time, the application of the aluminum piston body 2 reduces the overall weight of the piston by about 30% (compared to a full steel piston), meeting the needs of automobile lightweight design. The petal structure 5 further optimizes the flow characteristics of the brake fluid, shortening the brake response time by about 10% and improving the overall performance of the brake system.

[0029] In the embodiment, the piston head 1 has a diameter of 20 mm and a length of 15 mm, and the piston body 2 has a diameter of 25 mm and a total length of 40 mm (including the petal structure part). The above dimensions can be adjusted according to the requirements of the braking system of different vehicle models, for example, the diameters of the piston head 1 and the piston body 2 can be appropriately increased in heavy vehicles to improve the carrying capacity.

[0030] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A split press-fit aluminum piston, characterized by: The piston head is made of steel and the piston body is made of aluminum; the piston body is provided with a mounting hole, one end of the piston head is mounted in the mounting hole in interference, and the other end of the piston head is provided with an open slot for limiting the displacement of the brake shoe.

2. The split press-fit aluminum piston of claim 1, wherein: The end of the piston body away from the piston head is provided with petal structures, facilitating the flow of brake fluid.

3. The split press-fit aluminum piston of claim 2, wherein: The petal structures are six petal structures uniformly distributed in the circumference.

4. The split press-fit aluminum piston of claim 1, wherein: The piston head is provided with external splines, the mounting hole is provided with internal splines, and the piston head and the piston body are connected and fixed through the interference fit of the external splines and the internal splines.

5. The split press-fit aluminum piston of claim 1, wherein: The open slot is a through slot arranged along the radial direction of the piston head.

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