A method for manufacturing CVT chain plates

Abstract

A CVT chain plate manufacturing method, relating to the field of chain manufacturing technology, includes the following steps: step (1), design of raw material cross-sectional shape and material selection; step (2), precision stamping; step (3), heat treatment; and step (4), polishing. This invention employs a double-collapsed edge profiled flat steel tooth ring pressure plate precision stamping method, and the collapsed edge of the swing area of ​​the CVT chain plate is reserved with a specific extrusion allowance, significantly improving the dimensional accuracy of the CVT chain plate and enhancing the flexibility and stability of the CVT chain plate rotating around the conical wheel. Simultaneously, this invention designs a complete heat treatment process for the high-carbon alloy steel material of the CVT chain plate, effectively reducing the content of residual austenite on the chain plate surface, making the surface hardness and performance of the chain plate more stable, its wear resistance stronger, and improving the service life of the entire steel belt drive system.

Description

Technical Field

[0001] This invention relates to the field of chain manufacturing technology, and more specifically to a method for manufacturing CVT chain plates. Background Technology

[0002] The biggest difference between CVT (Continuously Variable Transmission) chain plates and traditional chain plates in terms of dimensions lies in the presence of two bulges on the surface of the CVT chain plate. The bulges near the saddle require extremely high precision, as their dimensional accuracy directly affects the smooth rotation and operational stability of the entire CVT steel belt. Currently, the industry widely uses rectangular strip materials for direct stamping, making dimensional control at the bulges very difficult and preventing the production of ideal products.

[0003] Meanwhile, CVT chain plates require high strength and high fatigue performance, which necessitates a preference for high-carbon steel in their material selection. However, the residual austenite on the surface of high-carbon steel after heat treatment is prone to soft spots, leading to decreased wear resistance on the friction surfaces between the CVT chain plate and the cone pulley, and between the saddle and the steel belt. As a result, the CVT chain plate may slip before reaching the expected lifespan of the entire continuously variable transmission system, ultimately causing abnormal failure of the steel belt. Summary of the Invention

[0004] This invention discloses a method for manufacturing CVT chain plates. The invention uses irregularly shaped flat steel structures as raw materials, solving the problem of insufficient dimensional control accuracy at the collapsed edges during stamping, thus improving transmission stability. Simultaneously, it proposes a CVT chain plate heat treatment process involving quenching, deep cooling, and tempering, effectively controlling the content of residual austenite on the surface, significantly improving the uniformity of surface hardness and performance stability of the chain plate, and extending the service life of the entire steel belt drive system.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A CVT chain plate manufacturing method includes the following steps: step (1) design of raw material cross-sectional shape and material selection; step (2) precision stamping; step (3) heat treatment; step (4) polishing.

[0007] Preferably, in step (1), the raw material is designed as an irregularly shaped flat steel structure. The irregularly shaped flat steel structure includes a flat steel body, and the left and right ends of the flat steel body are symmetrically provided with collapsed edge structures. The collapsed edge structures include a first collapsed edge and a second collapsed edge from the inside to the outside. The second collapsed edge is located at the edge of the upper surface of the flat steel body. There is a planar transition area between the first collapsed edge and the second collapsed edge. The inner end of the planar transition area is connected to the lower edge of the first collapsed edge, and the outer end of the planar transition area is connected to the upper edge of the second collapsed edge. The material of the irregularly shaped flat steel structure is selected as high-carbon alloy steel.

[0008] Preferably, the first collapsed edge 1-1 corresponds to the swing area 2-1 of the formed CVT chain plate 2, and the relationship between the collapsed edge angle θ of the first collapsed edge 1-1 and the collapsed edge angle θ' of the swing area of ​​the CVT chain plate satisfies: θ = θ' - (1.5° ~ 3°); the second collapsed edge 1-2 corresponds to the rounded corner position of the edge of the CVT chain plate 2 and is tangent to the rounded corner 2-2 when overlapping and comparing.

[0009] Preferably, the material of the irregular flat steel structure is 80CrV2.

[0010] Preferably, in step (2), a toothed ring pressure plate fine blanking method is used to arrange the irregular flat steel structure. The blanking gap δ and the thickness T of the CVT chain plate 2 satisfy the relationship: δ=(0.3%~1%)*T.

[0011] Preferably, in step (3), the heat treatment process includes quenching, cryogenic treatment, and tempering.

[0012] Preferably, in step (3), the quenching temperature is 780℃~840℃ and the time is 20~40min; the cryogenic treatment temperature is -120℃~-190℃ and the time is 1~2h; the tempering temperature is 180℃~200℃ and the time is 3~4h.

[0013] Preferably, in step (3), after heat treatment, the volume fraction of residual austenite on the surface of the workpiece is controlled to be less than 4%.

[0014] The beneficial effects of the CVT chain plate manufacturing method of the present invention are as follows:

[0015] This invention employs a double-collapsed, irregularly shaped flat steel toothed ring pressure plate precision stamping method, and the collapsed edge of the CVT chain plate's swing area is reserved with a specific extrusion allowance, significantly improving the dimensional accuracy of the CVT chain plate and enhancing its flexibility and stability in rotation around the conical pulley. Simultaneously, this invention designs a comprehensive heat treatment process for the high-carbon alloy steel material of the CVT chain plate, effectively reducing the content of residual austenite on the chain plate surface, resulting in more stable surface hardness and performance, stronger wear resistance, and extended service life of the entire steel belt drive system. Attached Figure Description

[0016] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the embodiments are briefly described below, which constitute a part of the specification and are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation on the present invention.

[0017] Figure 1 Cross-sectional diagram of irregularly shaped flat steel.

[0018] Figure 2A diagram showing the structural relationship when the flat steel body and the CVT chain plate cross section overlap.

[0019] Figure 3 , Figure 2 Enlarged view of the cross-sectional relationship in the figure.

[0020] Figure 4 Stamping layout diagram.

[0021] Figure 5 Heat treatment process diagram.

[0022] 1. Flat steel body; 1-1. First collapsed edge; 1-2. Second collapsed edge; 1-3. Planar transition zone; 2. CVT chain plate; 2-1. Swinging area; 2-2. Rounded corner. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. 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.

[0024] Example 1

[0025] A method for manufacturing CVT chain plates, such as Figure 1-5 As shown, the process includes the following steps: Step (1) Design of raw material cross-sectional shape and material selection; Step (2) Precision stamping; Step (3) Heat treatment; Step (4) Polishing.

[0026] Example 2

[0027] like Figure 1 , 2 As shown in Figure 3, in step (1), the raw material is designed as an irregular flat steel structure. The irregular flat steel structure includes a flat steel body 1. The flat steel body 1 has symmetrically provided collapsed edge structures on its left and right ends. The collapsed edge structures include a first collapsed edge 1-1 and a second collapsed edge 1-2 from the inside to the outside. The second collapsed edge 1-2 is located at the edge of the upper surface of the flat steel body 1. There is a planar transition area 1-3 between the first collapsed edge 1-1 and the second collapsed edge 1-2. The inner end of the planar transition area 1-3 is connected to the lower edge of the first collapsed edge 1-1, and the outer end of the planar transition area 1-3 is connected to the upper edge of the second collapsed edge 1-2. The material of the irregular flat steel structure is high carbon alloy steel.

[0028] Example 3

[0029] like Figure 1 , 2As shown in Figure 3, the first collapsed edge 1-1 corresponds to the swing area 2-1 of the formed CVT chain plate 2, and the relationship between the collapsed edge angle θ of the first collapsed edge 1-1 and the collapsed edge angle θ' of the swing area of ​​the CVT chain plate satisfies: θ = θ' - 1.5°; the second collapsed edge 1-2 corresponds to the rounded corner position of the edge of the CVT chain plate 2 and is tangent to the rounded corner 2-2 when overlapping and comparing.

[0030] Example 4

[0031] like Figure 1 , 2 As shown in Figures 1 and 3, the first collapsed edge 1-1 corresponds to the swing area 2-1 of the formed CVT chain plate 2. The relationship between the collapsed edge angle θ of the first collapsed edge 1-1 and the collapsed edge angle θ' of the swing area of ​​the CVT chain plate satisfies: θ = θ' - 3°.

[0032] Example 5

[0033] like Figure 1 As shown, the material selected for the irregular flat steel structure is 80CrV2.

[0034] Example 6

[0035] like Figure 4 , 5 As shown, in step (2), a toothed ring pressure plate fine blanking method is used to arrange the pattern on the irregular flat steel structure. The blanking gap δ and the thickness T of the CVT chain plate 2 satisfy the relationship: δ=0.3%*T.

[0036] Example 7

[0037] like Figure 4 , 5 As shown, in step (2), a toothed ring pressure plate fine blanking method is used to arrange the pattern on the irregular flat steel structure. The blanking gap δ and the thickness T of the CVT chain plate 2 satisfy the relationship: δ=1%*T.

[0038] Example 8

[0039] like Figure 5 As shown, in step (3), the heat treatment process includes quenching, cryogenic treatment, and tempering.

[0040] Example 9

[0041] like Figure 5 As shown, in step (3), the quenching temperature is 780℃ and the time is 20min; the cryogenic treatment temperature is -120℃ and the time is 1h; the tempering temperature is 180℃ and the time is 3h.

[0042] Example 10

[0043] like Figure 5As shown, in step (3), the quenching temperature is 840℃ and the time is 40min; the cryogenic treatment temperature is -190℃ and the time is 2h; the tempering temperature is 200℃ and the time is 4h.

[0044] Example 11

[0045] like Figure 5 As shown, in step (3), after heat treatment, the volume fraction of residual austenite on the surface of the workpiece is controlled to be less than 4%.

Claims

1. A method of manufacturing a CVT chain plate, characterized by: The process includes the following steps: Step (1) Design of the cross-sectional shape of the raw material and selection of the material; Step (2) Precision stamping; Step (3) Heat treatment; Step (4) Polishing; In step (1), the raw material is designed as an irregular flat steel structure, which includes a flat steel body. The flat steel body has symmetrically provided collapsed edge structures on its left and right ends. The collapsed edge structures include a first collapsed edge and a second collapsed edge from the inside to the outside. The second collapsed edge is located at the edge of the upper surface of the flat steel body. There is a planar transition area between the first collapsed edge and the second collapsed edge. The inner end of the planar transition area is connected to the lower edge of the first collapsed edge, and the outer end of the planar transition area is connected to the upper edge of the second collapsed edge. The material of the irregular flat steel structure is high carbon alloy steel. The first collapsed edge (1-1) corresponds to the swing area (2-1) of the formed CVT chain plate (2). The relationship between the collapsed edge angle θ of the first collapsed edge (1-1) and the collapsed edge angle θ' of the swing area of ​​the CVT chain plate is: θ = θ' - (1.5° ~ 3°); the second collapsed edge (1-2) corresponds to the rounded corner position of the edge of the CVT chain plate (2) and is tangent to the rounded corner (2-2) when overlapping and comparing. In step (3), the heat treatment process includes quenching, cryogenic treatment, and tempering; In step (3), the quenching temperature is 780℃~840℃ and the time is 20~40min; the cryogenic treatment temperature is -120℃~-190℃ and the time is 1~2h; the tempering temperature is 180℃~200℃ and the time is 3~4h.

2. The CVT chain plate manufacturing method as described in claim 1, characterized in that: The material selected for the aforementioned irregular flat steel structure is 80CrV2.

3. The CVT chain plate manufacturing method as described in claim 2, characterized in that: In step (2), a toothed ring pressure plate fine blanking method is used to arrange the pattern on the irregular flat steel structure. The blanking gap δ and the thickness T of the CVT chain plate (2) satisfy the following relationship: δ = (0.3% ~ 1%) T.

4. The CVT chain plate manufacturing method as described in claim 3, characterized in that: In step (3), after heat treatment, the volume fraction of residual austenite on the surface of the workpiece is controlled to be less than 4%.

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