CN100358654C - Crankshaft casting model classification method - Google Patents

Abstract

The present invention relates to a crankshaft casting model parting method, which is divided into an upper and lower mold along the center line of the main shaft connecting rods at both ends through the curved surfaces of the middle connecting rods. The parting surfaces of the middle connecting rods are parallel to the maximum cross-section and move toward the center line of the main shaft connecting rods to make the sand mold shallower. The corresponding positions of the connecting rods in the model are provided with draft subsidies. According to the arc shape of the connecting rod journal, the curved surface parting is adopted to make the crankshaft model. When the crankshaft is cast, the model of the present invention adopts the curved surface parting, so that it is not necessary to set the core separately during the modeling, and the sand mold is directly formed, eliminating the sand core. The operation is simple, the labor intensity of the workers is greatly reduced, the production efficiency is high, the appearance of the cast castings is neat and smooth, and the production cost can be greatly reduced. It can be mass-produced by mechanical automation. The method of the present invention is suitable for the production of crankshafts whose connecting rod axes are not on the same plane.

Description

Crankshaft casting model classification method

technical field

The invention relates to a casting method, in particular to a crankshaft casting model splitting method.

Background technique

We know that the crankshaft is one of the important machine parts, its structure and stress are complex, the workload is heavy, and the requirements for internal metallurgical quality, casting quality and forming precision are very high. Due to the irregular shape, it is easy to produce casting defects, which brings trouble to the finishing of the crankshaft blank. The parting method of the casting model is very critical for the demoulding operation and crankshaft forming. The traditional model classification method is along the center line, adopts plane classification, and splits as a whole. Generally, the parting (type) surface is selected at the largest cross-section of the casting, but due to the different structural design of the crankshaft, the axes of the connecting rods are often not on the same plane (0° or 180°), which leads to partial connection when parting the parting (type). The rod is either in the upper box or in the lower box. In this way, the designer usually cannot design the core seat at the place where the mold is drawn, and design the core box accordingly and make the core. After molding, the core is placed in the cavity. Make it form a complete structure; on the high-efficiency automatic molding line, due to the fast production pace, it is necessary to place the core, which affects the production efficiency on the one hand, and on the other hand, the labor intensity of the workers is relatively high; the use of cores requires core-making equipment Or manual core making increases investment and production costs. Due to the large amount of gas generated by the core, especially the resin core, it is easy to cause casting waste such as pores. For large-scale and automated production, the production preparation time is long, and the core During transportation and turnover, it is prone to moisture and damage from time to time.

Taking the six-cylinder crankshaft as an example, it is generally parted along the centerline of the first and sixth connecting rods, and the second, third, fourth and fifth connecting rods are in the upper and lower air at an angle of 120 degrees between the parting lines. If only one connecting rod cannot be ejected smoothly, it is necessary to lower the connecting rod core in the model to help eject the mold.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the above-mentioned prior art, and provide a crankshaft casting model splitting method with simple operation, greatly reduced labor intensity, high production efficiency, and neat and clean appearance of the cast castings.

The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a crankshaft casting model classification method, which is characterized in that: along the centerlines of the main shaft and connecting rods at both ends, the curved surfaces of the connecting rods in the middle are divided into upper and lower types, and the connecting rods in the middle are divided into two types: The parting surface is parallel to the maximum cross-section and moves toward the center line of the main shaft connecting rod, so that the sand tire mold becomes shallower. The corresponding position of the connecting rod mold in the model is provided with a draft subsidy. According to the arc shape of the connecting rod journal, the curved surface parting is adopted. Create a model of the crankshaft.

Both ends of the sand tire mold of the present invention are arc structures.

In the present invention, when the crankshaft is cast, the model is divided into curved surfaces, so that no additional cores are needed during the molding, and it is directly formed with sand tires, eliminating the need for sand cores. The operation is simple, the labor intensity of workers is greatly reduced, and the production efficiency is high. The appearance of the cast parts is neat and smooth, and the production cost can be greatly reduced. It can be mass-produced mechanically and automatically. The method of the invention is suitable for producing crankshafts whose connecting rod axes are not on the same plane.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is the schematic diagram of parting surface of model of the present invention;

Fig. 2 is a schematic structural view of the upper model of the X connecting rod of the present invention;

Fig. 3 is the structure schematic diagram of the lower model of the X connecting rod of the present invention;

In the figure 1. draft subsidy, 2. sand tire mold, 3. X connecting rod mold, 4. mold bottom plate, 6. sand tire mold.

Detailed ways

As can be seen from Fig. 1, Fig. 2, Fig. 3, a kind of crankshaft casting model parting method of the present invention, a kind of crankshaft casting model parting method, it is along the central line of the main shaft connecting rod at both ends, through the curved surface of each connecting rod in the middle Divided into upper and lower types, the parting surfaces of the connecting rods in the middle move parallel to the maximum section to the centerline of the main shaft connecting rod, that is, the parting surfaces of the connecting rods on the center line of the main shaft connecting rods at both ends move down parallel to the maximum section, and the two The parting surface of each connecting rod under the center line of the connecting rod of the end spindle moves up parallel to the maximum section, so that the sand tire molds 2 and 6 become shallower, and the corresponding position of the connecting rod mold in the model is provided with a draft subsidy 1, according to the connecting rod The arc shape of the journal is made into a crankshaft model by surface classification.

Take the 6-cylinder crankshaft as an example: the type is divided at the centerline of the first and sixth connecting rods; That is to say, the cross-sectional circle of the journal of the second and fifth connecting rods moves down along the tangent line perpendicular to the parting surface, as shown in Figure 1. Figure 2 and Figure 3 are schematic diagrams of the model structure of two and five connecting rods. Fig. 2 is a schematic diagram of the structure of the upper model of two and five connecting rods, and Fig. 3 is a schematic diagram of the structure of the lower model of two and five connecting rods. According to common sense, the third and fourth connecting rods are located at the lower part of the center line of the main shaft connecting rods, and their structures are just opposite to those of the second and fifth connecting rods. Move up. The schematic diagram of the lower model structure of the three- and four-link model can be shown in Figure 2, and the upper model structure schematic diagram of the three- and four-link model can be shown in Figure 3.

In the present invention, because the crankshaft connecting rod gear is relatively small (42mm), the parting surfaces of the second, third, fourth and fifth connecting rods are changed from the maximum point of the original circle to the current 22mm off center, so that the sand tire molds 2 and 6 become shallow and easy Pull out, and for the place where the connecting rod cannot be molded, increase the draft allowance 1, as shown in Figure 1, to make it the largest cross-section, and then make a curved surface according to the arc shape of the connecting rod journal to make a crankshaft model, so that the production At the same time, it can not only ensure the strength of the sand tire, avoid the expansion of the casting, reduce the difficulty of processing, but also achieve the convenience of mold removal.

During the production of the present invention, in order to ensure the moldability of the sand tire, the two ends of the sand tire mold 2,6 are all designed as arc structures, as shown in Figure 2 and Figure 3. High strength and easy to mold to avoid casting defects.

When the present invention is processed and manufactured, the crankshaft model is first installed and fixed on the mold bottom plate 4, and then processed according to the parting diagram, wherein the parting planes of the second and fifth connecting rods move down parallel to the maximum section, and the parting surfaces of the third and fourth connecting rods The profile moves up parallel to the largest section. Such as: during model manufacturing among Fig. 3, sink in the mold bottom plate 4, sand tire mold 6 forms sand tire during production, and sand tire becomes shallow, is easy to draft. During model manufacture among Fig. 2, sand tire mold 2 and the X connecting rod mold 3 form cavity. During crankshaft production, the sand tire that sand tire mold 6 forms among Fig. 3 fills up the part cavity in Fig. 2 upper mold, promptly fills up that part sand tire cavity that sand tire mold 2 forms. And the third connecting rod mold 3 forms a cavity to obtain a complete connecting rod journal.

Claims (2)

1, a kind of method for dividing model of casting crankshaft, it is characterized in that: along two ends main shaft connecting rod center line, be divided into amphitypy up and down through middle each connecting rod curved surface, the die joint of middle each connecting rod is parallel to the maximum cross-section and moves to main shaft connecting rod center line, sand match is shoaled, and the corresponding position of connecting rod is provided with the withdrawing pattern subsidy in the model, according to the rod journal circular shape, adopt the curved surface somatotype, make the bent axle model.

2, method for dividing model of casting crankshaft according to claim 1, it is characterized in that: the two ends of sand match are arc structure.

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