CN103736928B - A kind of evaporative pattern running gate system of gear box - Google Patents

Abstract

The invention discloses a lost foam pouring system for a gearbox case: a sprue is provided, and a sprue cup, a first runner and a second runner are sequentially connected on the sprue from top to bottom, The first runner and the second runner are respectively connected to the sprue along the radial direction of the sprue; and, at the ends of the first runner and the second runner away from the sprue The pouring port of the first inner runner and the pouring port of the second inner runner are respectively provided. By adopting the pouring system of the present invention for pouring castings, the filling time is shortened, the heat loss is reduced, shrinkage and shrinkage defects are greatly reduced, and the quality of castings is effectively improved.

Description

A lost foam pouring system for a gearbox case

Technical field:

The invention relates to a lost foam casting system, in particular to a lost foam casting system for a gearbox case.

Background technique:

Lost foam casting is to bond and combine paraffin or foam models similar in size and shape to castings to form model clusters. After brushing refractory paint and drying, they are buried in dry quartz sand for vibration modeling, and poured under negative pressure to vaporize the model. , a new casting method in which liquid metal occupies the position of the model, solidifies and cools to form a casting. The lost foam casting process includes pouring riser system design, pouring temperature control, pouring operation control, negative pressure control, etc. The gating system plays a very important role in the lost foam casting process and is a key to the success of casting production. Therefore, a reasonable gating system design plays a vital role in ensuring the quality of lost foam castings.

In the present invention, the gearbox box body is cast iron, the material is HT250, and it belongs to thin-walled parts. The box body specification is 560×480×420mm, and the wall thickness is uneven. -10t on forklift. The castings produced by the prior art often have problems such as shrinkage porosity and shrinkage cavity.

Invention content:

In order to overcome the defects of the prior art, the object of the present invention is to provide a new type of lost foam casting system for the gearbox case, which can significantly improve the casting quality.

The present invention solves technical problem and adopts following technical scheme:

A lost foam pouring system for a gearbox case:

A sprue is provided, and a sprue cup, a first runner, and a second runner are sequentially connected to the sprue from top to bottom, and the first runner and the second runner are respectively along the sprue. The radial direction of the sprue is connected to the sprue; and, the first sprue sprue and the second sprue are respectively provided at the ends of the first sprue and the second sprue away from the sprue Sprue.

The first runner is generally semicircular, the sprue is in the middle of the semicircular first runner, and the two first inner runner sprues at the end of the first runner are located at the Both sides of the upper half of the gearbox case.

Two of the second runners form a V shape, and the two second runners at the ends of the second runners are located at the thick part of the bottom of the gearbox case.

The cross sections of the first runner and the second runner are both trapezoidal, wherein the ratio of the bottom to the height of the trapezoidal section of the first runner is 2.6:1; the bottom to the height of the trapezoidal section of the second runner is The ratio is 0.73:1.

The sprue of the first ingate and the sprue of the second ingate are both frustum-shaped, and the cross-sectional area of the inner cavity of the frustum-shaped sprue gradually changes, and the ratio of the cross-sectional area of the molten metal inflow end to the molten metal outflow end is 2.25:1 .

Compared with the prior art, the beneficial effects of the present invention are reflected in:

The filling time of the present invention is relatively short, because the pouring system of the present invention is a stepped pouring system, the first runner and the second runner are divided into upper and lower layers, and the molten metal flows from the gate of the first runner, The sprue of the second runner is poured into the casting model in two layers, so the filling time is shortened and the heat loss is reduced. Since the present invention is a stepped pouring system, the first runner is provided with sprues on both sides of the upper half of the gearbox case, which can reduce shrinkage and shrinkage defects in the upper part of the box; the two pouring holes of the second runner The openings are distributed at the thick and large part of the bottom of the gearbox case, and its cross-sectional size is large, which can well feed the parts that are prone to shrinkage and shrinkage at the bottom of the case, greatly reducing shrinkage and shrinkage defects, and effectively improving improved casting quality.

Description of drawings:

Fig. 1 is a schematic structural diagram of the present invention; Fig. 2 is a schematic structural diagram of a gearbox case; Fig. 3 is a schematic diagram of an application state of the present invention.

Numbers in the figure: 1 sprue cup, 2 sprue, 3 first runner, 31 first inner runner sprue, 4 second runner, 41 second inner runner sprue, 5 gearbox box body.

The present invention will be further described below through specific embodiments and in conjunction with the accompanying drawings.

Detailed ways:

Embodiment: In combination with Figures 1-3, the lost foam casting system of the gearbox case of the present invention, the sprue 2 is connected with the sprue cup 1, the first runner 3 and the second runner 2 sequentially from top to bottom Road 4, the first runner 3 and the second runner 4 are respectively connected to the sprue 2 along the radial direction of the sprue; and, the first runner and the second runner are far away from the sprue The ends of the gates are respectively provided with a first ingate sprue 31 and a second ingate sprue 41 .

In the specific setting, the first runner 3 is generally semicircular, the sprue is in the middle of the semicircular first runner, and the two first inner runner gates 31 at the end of the first runner are in the Both sides of the upper half of the gearbox casing 5.

The second runners are two with different lengths and form a V shape, and the two second runner gates 41 at the ends of the second runners are located at the thick and large parts of the bottom of the gearbox case.

The cross-sections of the first runner 3 and the second runner 4 are both trapezoidal, wherein the ratio of the bottom to the height of the trapezoidal section of the first runner is 2.6:1; The ratio is 0.73:1.

The first ingate sprue 31 and the second ingate sprue 41 are both frustum-shaped, and the inner cavity cross-sectional area of the frustum-shaped sprue gradually changes, and the ratio of the cross-sectional area of the molten metal inflow end to the molten metal outflow end is 2.25:1 .

In a specific application, when the molten metal flows through the stepped gating system of the present invention, the molten metal flows from the sprue 2 into the first runner 3 and the second runner 4, and is injected into the casting through the respective sprues In the model, the filling time is short, the heat loss is greatly reduced, the molten metal maintains good fluidity, avoids the premature appearance of cold material, and can better control the temperature of the molten metal entering the cavity, which greatly improves the casting performance. quality. The first runner 3 and the second runner 4 have sufficient length to control the flow direction of the molten metal, and the first runner and the second runner are isolated from each other without interfering with each other, which can effectively prevent the formation of turbulence in the molten metal. Flow, to avoid gas inclusions in the molten metal, thereby effectively avoiding shrinkage cavities in castings. The cross-sectional shapes of the first runner 3 and the second runner 4 are trapezoidal, because the runners with trapezoidal cross-section have little heat loss of molten metal and are easy to process. Moreover, in the present invention, the cross-sectional size of the second runner 4 is larger than that of the first runner 3, which can well feed the parts prone to shrinkage and shrinkage at the bottom of the box, greatly reducing shrinkage and shrinkage Defects, improve casting quality.

In the specific setting, the specifications of sprue cup 1 are 240mm in diameter and 120mm in height. The section of the sprue 2 is circular, the size of the sprue is 50mm in diameter and 600mm in height, and the bottom is gradually changing from 70mm in diameter to 50mm in diameter and 250mm in height. The sprue 2 is located in the middle of one side of the box, 120mm away from the box; the section of the first runner 3 is trapezoidal, the section size is 45mm for the upper bottom, 65mm for the lower bottom, and 25mm for the height, and the ratio of the bottom to the height is 2.6:1. It is in the shape of a semicircle and surrounds both sides of the upper part of the box. The cross-section of the second runner 4 is also trapezoidal. The upper bottom is 34mm, the lower bottom is 44mm, and the height is 60mm. The ratio of the bottom to the height is 0.73:1. It is located at the bottom of the box. At the thick part. The sprue gate of the first ingate and the gate of the second ingate are in the shape of a truncated cone, the volume of the inner cavity gradually changes, the minimum cross section is 20mm in diameter, the maximum cross section is 30mm in diameter, and the ratio of the cross-sectional area of the gate entrance to the exit is 2.25: 1. The first inrunner pouring port 31 is located at the bosses on both sides of the upper part of the gearbox case, and the second inrunner pouring port 41 is located at the thick part at the bottom of the gearbox case. According to test and calculation, the pouring system of the present invention is used to cast the gearbox case, the filling time is 47.28s; the solidification time is 3159.4s; the maximum shrinkage porosity is 0.707%, which effectively improves the casting quality.

Claims (4)

1. an evaporative pattern running gate system for gear box, is characterized in that:

Sprue (2) is set, described sprue is communicated with cup (1), the first cross gate (3) and the second cross gate (4) from top to bottom successively, and described first cross gate (3) and the respective radial communication along described sprue of the second cross gate (4) are on sprue (2); Further, the first ingate sprue gate (31), the second ingate sprue gate (41) is respectively equipped with at the first cross gate, the second cross gate away from the end of sprue;

Described first cross gate (3) is totally semicircle, and described sprue is in the middle part of semicircle first cross gate, and two first ingate sprue gates (31) point of described first cross gate end are in gear box first half both sides.

2. the evaporative pattern running gate system of a kind of gear box according to claim 1, it is characterized in that, described second cross gate is two, and form V-shaped, two the second ingate sprue gates (41) of the second cross gate end are in thick large part place bottom gear box.

3. the evaporative pattern running gate system of a kind of gear box according to claim 1, it is characterized in that, the cross section of described first cross gate (3), the second cross gate (4) is trapezoidal, and wherein, the end of the first cross gate trapezoid cross section is 2.6:1 with the ratio of height; 0.73:1 with the ratio of height at the bottom of second cross gate trapezoid cross section.

4. the evaporative pattern running gate system of a kind of gear box according to claim 1, it is characterized in that, described first ingate sprue gate (31), the second ingate sprue gate (41) are truncated cone-shaped, and the intracavity section at truncated cone-shaped sprue gate gradually becomes, it is 2.25:1 that molten metal inflow end flows out end cross-sectional area ratio with molten metal.