A design method of a pouring system for a thin-wall cast iron cylinder block of a commercial vehicle

Abstract

The present application relates to a kind of commercial vehicle thin-wall cast iron cylinder body pouring system design method, including with the upper and lower bearing position of the position of the top end of cylinder body relatively close as inner gate;The center line position of cross gate is offset to the direction of upper bearing inner gate;Adjust the size of upper bearing inner gate, and increase the flow of molten iron of upper bearing inner gate;Adjust the size of lower bearing inner gate, and reduce the flow of molten iron of lower bearing inner gate;The peak waist of inner gate and casting connecting area is designed around according to specific size, and break groove is set;Each inner gate is formed by two sand cores;After process design is completed, filling simulation is carried out, and improvement effect is confirmed.The present application can reduce the temperature drop of the top end area of casting by 20 DEG C by comparing the application of pouring system with the application of bottom pouring system through simulation software, reduces the temperature difference between the top end and bottom end of casting, and the newly designed middle pouring system is verified by batch production, and the problem of casting porosity defect is greatly improved, and the waste rate of porosity is reduced by more than 50%.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automobile manufacturing, and particularly relates to a design method of a thin-wall cast iron cylinder body pouring system of a commercial vehicle. BACKGROUND

[0002] The cast iron cylinder body of the commercial vehicle with a small displacement has the characteristics of a complex structure and a thin outer wall of a water cavity. In order to ensure that the molten iron fills the mold smoothly during pouring, the traditional bottom pouring system is used in the process of the pouring system of the castings. The molten iron of the castings using the bottom pouring system enters from the bottom of the cylinder body. Since the cylinder body is thin-walled and has a complex structure, the temperature loss is large during the upward movement of the molten iron. After the pouring of the cylinder body is completed, the temperature of the top end region of the castings farthest from the bottom pouring system is the largest, which is not conducive to the discharge of the gas in the molten iron and is easy to form a gas hole defect. At present, the scrap rate of the gas hole is more than 2.5%. SUMMARY

[0003] The purpose of the present application is to provide a design method of a thin-wall cast iron cylinder body pouring system of a commercial vehicle, so as to solve the problems of large temperature drop during the filling of the molten iron and easy occurrence of gas holes in the castings.

[0004] The purpose of the present application is achieved by the following technical solutions.

[0005] A design method of a thin-wall cast iron cylinder body pouring system of a commercial vehicle, comprising the following steps:

[0006] A. The position of the inner gate is modified, the original inner gate at the bottom end flange position is cancelled, and the inner gate is changed to the upper and lower bearing positions closer to the top end position of the cylinder body;

[0007] B. The center line position of the cross gate is offset to the direction of the upper bearing inner gate;

[0008] C. The size of the upper bearing inner gate is adjusted, and the molten iron flow of the upper bearing inner gate is increased;

[0009] D. The size of the lower bearing inner gate is adjusted, and the molten iron flow of the lower bearing inner gate is reduced;

[0010] E. The peak waist of the connection area between the inner gate and the castings is designed in a certain size around the circumference, and a breaking groove is provided;

[0011] F. Each inner gate is formed by two sand cores;

[0012] G. After the process design is completed, the filling simulation is carried out to confirm the improvement effect.

[0013] Further, in step B, the offset distance is 10-12 mm.

[0014] Further, the offset distance is 12 mm.

[0015] Further, in step C, the upper gate minimum size is set to 22mm*13mm.

[0016] Further, in step D, the lower gate maximum size is set to 20mm*10mm.

[0017] Further, in step E, the gate and casting connection area peak waist is designed to be surrounded by 1-3mm*1-3mm.

[0018] Further, the gate and casting connection area peak waist is designed to be surrounded by 3mm*3mm.

[0019] Further, the breaking groove is 1-2mm wide and 1-2mm deep.

[0020] Further, the breaking groove is 2mm wide and 1mm deep.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] The present application is a design method for a commercial vehicle thin-wall cast iron cylinder body gating system, which redesigns the middle gating system. By means of simulation software, it is confirmed that compared with the bottom gating system, the middle gating system can reduce the temperature drop of the top end area of the casting by 20℃, reduce the temperature difference between the top end and the bottom end of the casting, and at the same time, the newly designed middle gating system is verified by batch production, and the casting porosity defect problem is greatly improved, and the porosity waste rate is reduced by more than 50%. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0024] Figure 1 Structure schematic diagram of the commercial vehicle thin-wall cast iron cylinder body gating system;

[0025] Figure 2 Gate cross-sectional view;

[0026] Figure 3 Filling simulation result schematic diagram. DETAILED DESCRIPTION

[0027] The present application will be further described below in combination with the embodiments:

[0028] The application will be described in further detail below with reference to the drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not to be used to limit the application. In addition, it should be noted that, for the sake of brevity, only the portions of the drawings that are necessary for an understanding of the application will be described.

[0029] It should be noted that like reference numerals and letters refer to like items in the drawings, and thus once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings. Also, in the description of the application, the terms "first", "second", and the like are used only to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0030] The application discloses a design method for a commercial vehicle thin-wall cast iron cylinder body pouring system, comprising the following steps:

[0031] 1. Modify the position of the inner gate, cancel the original inner gate at the bottom end flange position, and change it to the inner gate at the upper and lower bearing positions closer to the top end position of the cylinder body.

[0032] 2. Offset the center line position of the cross gate to the direction of the upper bearing inner gate.

[0033] Specifically, the offset distance is 10-12 mm, preferably 12 mm.

[0034] 3. Adjust the size of the upper bearing inner gate and increase the molten iron flow of the upper bearing inner gate.

[0035] Specifically, the minimum size of the upper bearing inner gate is set to 22 mm*13 mm.

[0036] 4. Adjust the size of the lower bearing inner gate and reduce the molten iron flow of the lower bearing inner gate.

[0037] Specifically, the maximum size of the lower bearing inner gate is set to 20 mm*10 mm.

[0038] 5. Design the peak waist of the inner gate and the connecting area of the casting in a specific size around the circumference, and open a breaking groove.

[0039] Specifically, the peak waist of the inner gate and the connecting area of the casting is designed in a size of 1-3 mm*1-3 mm around the circumference, preferably 3 mm*3 mm. The breaking groove is 2 mm wide and 1 mm deep, preferably 2 mm wide and 1 mm deep.

[0040] 6. Each inner gate is formed by two sand cores.

[0041] 7. After the process design is completed, perform filling simulation to confirm the improvement effect.

[0042] Example 1

[0043] As Figure 1 shown, the commercial vehicle thin-wall cast iron cylinder body pouring system design method of the application comprises the following steps:

[0044] 1. In order to improve the temperature of the molten iron at the top end of the cylinder body, the upper and lower bearing positions close to the top end position of the cylinder body are used as the inner gate, and the original bottom end flange position inner gate is cancelled to avoid the problem of large temperature drop when the molten iron at the bottom flange inner gate position fills the cylinder body top end position;

[0045] 2. The center line position of the cross gate is offset by 12mm to the direction of the upper bearing inner gate to reduce the flow distance of the molten iron in the upper bearing inner gate and reduce the temperature loss of the molten iron;

[0046] 3. The minimum size of the upper bearing inner gate is set to 22mm*13mm to increase the molten iron flow in the upper bearing inner gate and reduce the temperature loss during the molten iron flowing through the upper bearing inner gate;

[0047] 4. The maximum size of the lower bearing inner gate is set to 20mm*10mm to reduce the molten iron flow in the lower bearing inner gate, alleviate the impact of the large molten iron flow in the lower bearing inner gate on the mold sand core, and avoid the problem of sand core;

[0048] 5. The peak waist of the inner gate and the casting connection area is designed to be 3mm*3mm around, and a 2mm wide and 1mm deep breaking groove is designed to avoid the problem of meat loss of the casting body during the removal of the pouring system;

[0049] 6. Each inner gate is formed by two sand cores to avoid the loose sand core problem caused by the formation of an inner gate by one sand core and reduce the tendency of sand core sand eye;

[0050] 7. After the process design is completed, the filling simulation is carried out to confirm the improvement effect, and the simulation results show that the top end temperature of the casting using the middle pouring pouring system is 20℃ higher than that of the bottom pouring pouring system, and the lower bearing inner gate has no sand impact problem.

[0051] The pouring system has been successfully applied in large quantities in our factory 4DD series cylinder body, and through the development and application of the middle pouring pouring system, the porosity waste rate has been reduced from more than 2.5% to less than 1% at present; At the same time, due to the cancellation of the bottom end inner gate, the impact of the molten iron on the sand mold is reduced, and the lower mold coating spraying is also cancelled, further reducing the production cost.

[0052] Note that the above merely describes preferred embodiments of the present application and the principles of the technology applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, modifications and substitutions can be made without departing from the scope of the present application. Therefore, although the present application has been described in detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the claims.

Claims

1. A method of designing a thin-wall cast-iron cylinder block pouring system for a commercial vehicle, characterized in that, The method comprises the following steps: A. Modify the position of the ingate, cancel the original bottom end flange position ingate, and change it to the upper and lower bearing positions closer to the top end position of the cylinder body as the ingate; B. Shift the center line position of the cross gate to the direction of the upper bearing ingate; the offset distance is 12 mm; C. Adjust the size of the upper bearing ingate and increase the molten iron flow of the upper bearing ingate; the minimum size of the upper bearing ingate is set to 22 mm*13 mm; D. Adjust the size of the lower bearing ingate and reduce the molten iron flow of the lower bearing ingate; the maximum size of the lower bearing ingate is set to 20 mm*10 mm; E. Design the peak waist of the ingate and the connecting area of the casting according to a specific size around the circumference, and open a breaking groove; the peak waist of the ingate and the connecting area of the casting is designed according to 3 mm*3 mm around the circumference; the breaking groove is 2 mm wide and 1 mm deep; F. Each ingate is formed by two sand cores; G. After the process design is completed, perform filling simulation to confirm the improvement effect.

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