Spring brake cylinder front shell with metal-plastic composite structure

Abstract

The invention relates to the technical field of spring brake cylinders, and discloses a spring brake cylinder front shell of a metal-plastic composite structure, the spring brake cylinder front shell comprises a support and a shell, the alloy support and the shell are connected through a connecting part, and a bottom chamfer and a step chamfer are arranged at the combination part of a circular shaft part and a flange of the support. The connecting component is provided with a connecting structure groove and a connecting structure hole, a step is arranged at the tail end of the circular shaft of the support, a step seam allowance comprises a seam allowance wall and a seam allowance groove, and a seam allowance wall hole is formed in the seam allowance wall. According to the reinforced structure of the alloy support, the bearing strength of the alloy part is greatly enhanced, and the risk of breakage is reduced.

Description

Technical Field

[0001] This invention relates to the field of spring brake cylinder technology, and more particularly to a front housing of a spring brake cylinder with a metal-plastic composite structure. Background Technology

[0002] As a core load-bearing component of a vehicle's braking system, the technological evolution of the spring brake cylinder front housing is closely linked to the automotive industry's demands for lightweighting and reliability. Early designs commonly used cast iron or aluminum alloys. While these materials could meet the strength requirements under operating conditions, they had limitations such as high weight (accounting for 15%-20% of the total braking system weight), complex processing (requiring multiple machining steps), and high cost. With the increasing penetration rate of new energy vehicles, the energy efficiency disadvantages of traditional materials have become increasingly apparent. For example, the increased unsprung mass caused by cast iron housings significantly reduces the driving range of electric vehicles.

[0003] With technological advancements, glass fiber reinforced engineering plastics (such as PA66 GF30) are gradually replacing metals due to their high strength (tensile strength 100MPa), low density (density 1.35 g / cm³), and corrosion resistance. Simultaneously, metal-plastic composite structures have become the mainstream solution. For example, patent application CN202311603105.1 uses a combination of an aluminum alloy base (withstanding high stress) and a PA6+GF30 upper shell (lightweight), achieving a 20%-30% weight reduction while maintaining strength. However, the strength and reliability of the connection between the plastic and aluminum alloy still need further improvement. Summary of the Invention

[0004] To overcome the above shortcomings, the present invention provides a metal-plastic composite structure for the front housing of a spring brake cylinder, which improves upon the strength and reliability issues of the connection between the plastic and aluminum alloy in existing spring brake cylinder front housings.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a front housing of a spring brake cylinder with a metal-plastic composite structure, comprising a support and a housing, wherein the alloy support and the housing are connected by a connecting component, wherein the circular shaft portion of the support and the flange joint portion are provided with a bottom chamfer and a stepped chamfer, wherein the connecting component is provided with a connecting structure groove and a connecting structure hole, wherein the end of the circular shaft of the support is provided with a step, wherein the step opening includes a step wall and a step groove, and the step wall is provided with a step wall hole.

[0006] Furthermore, the support connection structure is a knurled structure.

[0007] Furthermore, the support connection structure is one or more connection structure groove structures.

[0008] Furthermore, the support connection structure is one or more connection hole structures.

[0009] Furthermore, the support connection structure is one or more sub-groove structures.

[0010] Furthermore, the sub-mouth wall is provided with one or more holes.

[0011] The present invention has the following beneficial effects: 1. The spring brake cylinder front housing utilizes a composite of plastics and alloys, achieving a weight reduction of 20%-30% while maintaining strength; 2. By coordinating the processes for the plastic and alloy components, a composite structure connecting the plastic and alloy components was achieved. 3. Multiple connection structures were designed to facilitate the composite process of plastics and alloys, enhance the connection structure and reliability, and ensure process controllability. 4. A reinforced structure for the alloy support was achieved, which greatly enhanced the supporting strength of the alloy part and reduced the risk of fracture. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of the front housing of a spring brake cylinder with a metal-plastic composite structure proposed in this invention. Figure 2 This is a cross-sectional view of the front housing support of a spring brake cylinder with a metal-plastic composite structure proposed in this invention. Figure 3 This is a perspective view of a metal-plastic composite structure spring brake cylinder front housing support and connecting components proposed in this invention. Figure 4 This is a schematic diagram of the front housing connection component of a spring brake cylinder with a metal-plastic composite structure proposed in this invention. Figure 5 This is a schematic diagram of the front housing connecting component of a metal-plastic composite spring brake cylinder after it is integrated with the housing, as proposed in this invention.

[0013] Legend: 1. Support; 2. Shell; 3. Connecting component; 4. Stepped opening; 101. Bottom chamfer; 102. Step chamfer; 103. Connecting structure groove; 104. Connecting structure hole; 105. Opening wall; 106. Opening groove; 107. Opening wall hole. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] like Figure 1 The diagram shows a cross-sectional view of the front housing of a plastic-alloy composite spring brake cylinder. Support 1 is made of alloy, preferably aluminum alloy, while housing 2 is made of plastic, preferably nylon PA6 + 50% glass fiber composite engineering material. The two are connected and fixed together at connecting component 3. There are two connection methods: one is direct bonding with structural adhesive, and the other is injection molding and overmolding the plastic housing 2 onto the connecting area of ​​support 1.

[0016] Preferably, the support 1 is integrally formed using a high-pressure casting process to create the required connecting component 3. The structure of the connecting component 3 can be a combination of multiple methods or a combination of multiple methods. After the high-pressure cast alloy support completes the secondary machining of the hollow inner hole structure, it is placed into an injection mold for injection molding and overmolding, thereby forming... Figure 1 The front housing of the integral spring brake cylinder is shown.

[0017] like Figure 2 The diagram shows a cross-sectional view of support 1. The section where the round shaft meets the flange features a step and two fillets. This double-fillet structure optimally strengthens the connection between the round shaft and the flange, significantly improving reliability, especially under high-intensity fatigue vibration conditions. Here, d2 is the outer diameter of the round shaft. A step with a larger diameter, d1, is added at the connection. The height of this step is d3. A fillet 101 is located between the cylindrical surface of the step and the plane of the bottom flange, and a fillet 102 is located between the plane of the step and the cylindrical surface of the round shaft. Preferably, d1 = d2 + 2. The radii of the bottom fillet 101 and the step fillet 102 are equal. Within the constraints of available assembly space, the fillet radius is maximized, with d3 = fillet radius + 1.

[0018] like Figure 2 The diagram shows a typical connecting structure groove 103 and a connecting structure hole 104, which are holes designed on the circular shaft wall of the connecting area. Both the connecting structure groove 103 and the connecting structure hole 104 are multiple in number, and their arrangement conforms to the draft direction of the high-pressure casting process. Figure 4 As shown, there is another connection structure for the connection area, namely, a stepped opening 4 is designed at the end of the round shaft of the alloy support, wherein the wall 105 of the opening is through the outer surface of the round shaft, the opening groove 106 is a groove between the opening and the outside of the round shaft, and the opening wall hole 107 is a plurality of holes opened on the opening wall 105, but the opening wall hole 107 does not penetrate the entire wall thickness of the round shaft. This form of connection structure is also suitable for high pressure casting process.

[0019] like Figure 5 yes Figure 4A schematic diagram of the connecting component 3 after it is integrated with the housing 2. When a secondary overmolding process is used, the nylon + glass fiber composite material will fill the slot 106, increasing the contact area between the plastic and the alloy, making the whole more stable. The plastic material will penetrate through the hole 107 in the slot wall and fit into the support 1, greatly increasing the overall tensile strength.

[0020] like Figure 5 yes Figure 4 This is a schematic diagram showing the connection structure integrated with the plastic shell. When using structural adhesive, the adhesive can be applied first to the groove 106 to control the amount. Then, the entire assembly is installed into the plastic shell, bonding with the corresponding structure. Because the plastic shell and alloy bracket fit precisely in the connection area, all the adhesive fills the through-hole 107 in the groove wall before fitting into the alloy support 1, significantly increasing the overall tensile strength. Excess adhesive overflows evenly throughout the connection area. When the amount of adhesive is controlled, it can cover the entire connection area without seeping from the joints at both ends. Controlling adhesive seepage ensures both uniformity and aesthetics while reducing contact between the adhesive and air, thus minimizing the risk of aging and oxidation.

[0021] It should be noted that, regardless of whether a secondary overmolding process or a structural adhesive bonding process is used, multiple connection structures can be combined to achieve the maximum connection strength and the minimum processing cost.

[0022] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A front housing of a spring brake cylinder with a metal-plastic composite structure, comprising a support (1) and a housing (2), characterized in that: The support (1) and the housing (2) are connected by a connecting component (3).

2. The front housing of a spring brake cylinder with a metal-plastic composite structure according to claim 1, characterized in that: The support (1) has a bottom chamfer (101) and a step chamfer (102) at the junction of the round shaft part and the flange.

3. The front housing of a spring brake cylinder with a metal-plastic composite structure according to claim 1, characterized in that: The connecting component (3) is provided with a connecting structure groove (103) and a connecting structure hole (104).

4. The front housing of a spring brake cylinder with a metal-plastic composite structure according to claim 1, characterized in that: A stepped opening (4) is provided at the end of the circular shaft of the support (1). The stepped opening (4) includes an opening wall (105) and an opening groove (106). An opening hole (107) is provided on the opening wall (105).

5. The front housing of a spring brake cylinder with a metal-plastic composite structure according to claim 1, characterized in that: The support (1) has a knurled connection structure.

6. The front housing of a spring brake cylinder with a metal-plastic composite structure according to claim 1, characterized in that: The support (1) connection structure is one or more connection structure slot structures.

7. The front housing of a spring brake cylinder with a metal-plastic composite structure according to claim 1, characterized in that: The support (1) connection structure is one or more connection structure hole structures.

8. The front housing of a spring brake cylinder with a metal-plastic composite structure according to claim 1, characterized in that: The support (1) connection structure is one or more sub-groove structures.

9. The front housing of a spring brake cylinder with a metal-plastic composite structure according to claim 4, characterized in that: The sub-mouth wall (105) has one or more holes.

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