阅读说明：本技术 一种铸造砂芯型腔内的排气结构 (Exhaust structure in casting sand core die cavity ) 是由 张勇 于 2019-12-09 设计创作，主要内容包括：本发明公开了一种铸造砂芯型腔内的排气结构,在上箱体与下箱体的砂芯接触面处开设第一通气孔道和第二通气孔道,第一通气孔道内穿接第一排气管,第一排气管连接第一缓冲罐,第一缓冲罐设第一导热活塞、第一气门嘴及第一气泵；第二通气孔道内穿接第二排气管,第二排气管连接第二缓冲罐,第二缓冲罐设第二导热活塞、第二气门嘴及第二气泵；上箱体砂芯的顶面处开设浇冒口及漏斗塞。本发明通过导热的活塞筒体将型腔与有机气体的压缩及气液变化联系起来,使浇注初始阶段型腔内气温及气压的骤升经过缓冲罐的缓冲,大幅度减小气流对型腔的冲击力,避免现有排气过程对型腔结构性的破坏,从而减少铸件表面缺陷的生成。(The invention discloses an exhaust structure in a casting sand core cavity, wherein a first vent hole and a second vent hole are formed in the sand core contact surface of an upper box body and a lower box body, a first exhaust pipe penetrates through the first vent hole and is connected with a first buffer tank, and the first buffer tank is provided with a first heat-conducting piston, a first air valve and a first air pump; a second exhaust pipe is connected in the second vent hole in a penetrating manner, the second exhaust pipe is connected with a second buffer tank, and the second buffer tank is provided with a second heat-conducting piston, a second valve and a second air pump; and a casting head and a funnel plug are arranged on the top surface of the upper box sand core. The invention relates the compression of the cavity and the organic gas and the gas-liquid change through the heat-conducting piston cylinder, so that the sudden rise of the air temperature and the air pressure in the cavity at the initial pouring stage is buffered by the buffer tank, the impact force of the air flow on the cavity is greatly reduced, the structural damage of the cavity in the existing exhaust process is avoided, and the generation of the surface defect of the casting is reduced.)

1. The exhaust structure in the casting sand core cavity is characterized in that a first ventilation hole (3) and a second ventilation hole (4) are formed in the sand core contact surface of an upper box body (1) and a lower box body (2), the first ventilation hole (3) is formed by a semicircular groove formed in the bottom surface of the sand core of the upper box body (1) and a semicircular groove formed in the top surface of the sand core of the lower box body (2), the second ventilation hole (4) is formed by another semicircular groove formed in the bottom surface of the sand core of the upper box body (1) and another semicircular groove formed in the top surface of the sand core of the lower box body (2), and the first ventilation hole (3) and the second ventilation hole (4) are both horizontally arranged and are arranged on the same straight line.

2. A first exhaust pipe (5) penetrates through the first air vent (3), one end of the first exhaust pipe (5) extends into the sand core cavity, the other end of the first exhaust pipe (5) extends out of the sand core cavity and is connected with a first buffer tank (6), a first heat-conducting piston (7) is connected in the first buffer tank (6) in a sealing and sealing mode, the first buffer tank (6) is split into a gas chamber and a liquid chamber by the first heat-conducting piston (7), volatile organic gas is filled in the liquid chamber, a first air valve nozzle (8) is arranged at the top of the outer side wall of the first buffer tank (6), the first exhaust pipe (5) is connected to the lower portion of the outer side wall of the first buffer tank (6), the vertical distance from the first exhaust pipe (5) to the bottom wall of the first buffer tank (6) is smaller than the thickness of the first heat-conducting piston (7), and a first air pump (9) is connected to the bottom wall of the first buffer tank (6) through a pipeline, and the outlet at the other end of the first air pump (9) is communicated with the atmosphere.

3. A second exhaust pipe (10) penetrates through the second vent hole (4), one end of the second exhaust pipe (10) extends into the sand core cavity, the other end of the second exhaust pipe (10) extends out of the sand core cavity and is connected with a second buffer tank (11), a second heat-conducting piston (12) is connected in the second buffer tank (11) in a sealing and sealing mode, the second buffer tank (11) is split into a gas chamber and a liquid chamber by the second heat-conducting piston (12), the liquid chamber is filled with volatile organic gas, a second air valve (13) is arranged at the top of the outer side wall of the second buffer tank (11), a second air pump (14) is connected to the lower portion of the outer side wall of the second buffer tank (11) through a pipeline, the vertical distance between the pipeline communicated with the second buffer tank (11) and the bottom wall of the second buffer tank (11) is smaller than the thickness of the second heat-conducting piston (12), an outlet at the other end of the second air pump (9) is communicated with the atmosphere, and the second exhaust pipe (10) is connected to the bottom wall of the second buffer tank (11).

4. A casting head (15) is arranged on the top surface of the sand core of the upper box body (1), the top end opening of the casting head (15) is funnel-shaped, and a funnel plug (16) is sleeved on the top end opening of the casting head (15).

5. The exhaust structure in the casting sand core cavity as recited in claim 1, characterized in that the inner walls of the first and second vent holes (3, 4) are coated with paint, when the first and second exhaust pipes (5, 10) are drawn out, a first plug (17) is sleeved in the first vent hole (3), a second plug (18) is sleeved in the second vent hole (4), one end of each of the first and second plugs (17, 18) is flush with the inner wall of the cavity, and the other end is provided with a flange ring and fastened to the outer walls of the upper and lower boxes (1, 2) respectively by pins.

6. The exhaust structure in the casting sand core cavity according to claim 1, wherein the first heat conducting piston (7) and the second heat conducting piston (12) are both piston bodies formed by penetrating arc-shaped heat conducting aluminum strips in a cylinder made of polyfluoro plastics and processing joints through sealant, and one end of each arc-shaped heat conducting aluminum strip is positioned in the gas chamber, and the other end of each arc-shaped heat conducting aluminum strip is positioned in the liquid chamber.

7. The exhaust structure in the casting sand core cavity according to claim 1, wherein the volatile organic gas filled in the liquid chamber of the first buffer tank (6) is any one of diethyl ether, acetone, ethanol and n-butane.

8. The method of using a venting structure in a casting core cavity according to claim 1, comprising the steps of:

a. before casting liquid is poured, a first exhaust pipe (5) and a second exhaust pipe (10) are respectively arranged in a first vent hole (3) and a second vent hole (4), a funnel plug (16) of a casting head (15) is opened, a first air pump (9) and a second air pump (14) are started, the flux of the first exhaust pipe (5) and the flux of the second exhaust pipe (10) are both 0.1-0.15T, the first exhaust pipe (5) and the second exhaust pipe (10) are blown oppositely, the casting head (15) is closed, when the air pressure in a first buffer tank (6) and the air pressure in a second buffer tank (11) are 0.3-0.35MPa, the first air pump (9) and the second air pump (14) are stopped, and a pipeline valve between the first air pump (9) and the first buffer tank (6) and a pipeline valve between the second air pump (14) and the second buffer tank (11) are closed.

B, slightly deflating during casting of the casting liquid, opening the first air pump (9) and the second air pump (14) to enable the first exhaust pipe (5) and the second exhaust pipe (10) to simultaneously exhaust air in the sand core cavity, wherein the flux of the first exhaust pipe (5) and the flux of the second exhaust pipe (10) are both 0.03-0.05T, when the casting liquid occupies 1/3 of the cavity volume, quickly exhausting the first exhaust pipe (5) and the second exhaust pipe (10), and plugging the first vent channel (3) and the second vent channel (4) through the first plug (17) and the second plug (18), wherein the casting is not stopped in the process until the casting is finished.

Technical Field

The invention relates to the technical field of sand casting, in particular to an exhaust structure in a casting sand core cavity.

Background

Currently, sand casting is still the main forming method of pig iron castings, and the sand casting generally adopts two or three boxes to be assembled to finally form the required sand core shape. After the several boxes are assembled, the sand core is substantially formed, at which point the structural stability of the mold cavity is very important. If the pressure in the cavity is too large, the casting liquid is not easy to flow to each corner position during pouring; if the pressure in the cavity is too low, the sand core is too loose due to the action of negative pressure, so that the sand, coal ash or other powder falls off from the inner wall of the cavity, and more casting defects are caused.

However, the existing exhaust system for sand casting mainly depends on exhaust pin holes, exhaust plugs or exhaust heads, the internal pressure and the air temperature of a cavity extremely change at the moment of casting liquid pouring, and the internal pressure is extremely easy to change suddenly.

Disclosure of Invention

The invention aims to solve the defects in the prior art and provides an exhaust structure in a casting sand core cavity.

In order to achieve the purpose, the invention adopts the following technical scheme:

an exhaust structure in a casting sand core cavity is characterized in that a first vent hole and a second vent hole are formed in the sand core contact surface of an upper box body and a lower box body, the first vent hole is composed of a semicircular groove formed in the bottom surface of a sand core of the upper box body and a semicircular groove formed in the top surface of a sand core of the lower box body, the second vent hole is composed of another semicircular groove formed in the bottom surface of the sand core of the upper box body and another semicircular groove formed in the top surface of the sand core of the lower box body, and the first vent hole and the second vent hole are horizontally arranged and are on the same straight line;

a first exhaust pipe penetrates through the first air vent, one end of the first exhaust pipe extends into the sand core cavity, the other end of the first exhaust pipe extends out of the sand core cavity and is connected with a first buffer tank, a first heat-conducting piston is connected in the first buffer tank in a sealing manner, the first buffer tank is divided into a gas chamber and a liquid chamber by the first heat-conducting piston, volatile organic gas is filled in the liquid chamber, a first air valve nozzle is arranged at the top of the outer side wall of the first buffer tank, the first exhaust pipe is connected to the lower part of the outer side wall of the first buffer tank, the vertical distance from the first exhaust pipe to the bottom wall of the first buffer tank is smaller than the thickness of the first heat-conducting piston, a first air pump is connected to the bottom wall of the first buffer tank through a pipeline, and an outlet at the;

a second exhaust pipe is connected in the second vent hole in a penetrating manner, one end of the second exhaust pipe extends into the sand core cavity, the other end of the second exhaust pipe extends out of the sand core cavity and is connected with a second buffer tank, a second heat-conducting piston is sleeved in the second buffer tank in a sealing manner and divides the second buffer tank into a gas chamber and a liquid chamber, volatile organic gas is filled in the liquid chamber, a second valve nozzle is arranged at the top of the outer side wall of the second buffer tank, a second air pump is connected to the lower part of the outer side wall of the second buffer tank through a pipeline, the vertical distance between the pipeline for communicating the second air pump with the second buffer tank and the bottom wall of the second buffer tank is smaller than the thickness of the second heat-conducting piston, an outlet at the other end of the second air pump is communicated with the atmosphere, and the second exhaust pipe is connected;

the top surface of the upper box sand core is provided with a casting head, the top end opening of the casting head is funnel-shaped, and the top end opening of the casting head is sleeved with a funnel plug.

Preferably, the inner walls of the first ventilation channel and the second ventilation channel are coated with paint, when the first exhaust pipe and the second exhaust pipe are drawn out, a first plug is sleeved in the first ventilation channel, a second plug is sleeved in the second ventilation channel, one end of each of the first plug and the second plug is flush with the inner wall of the cavity, and the other end of each of the first plug and the second plug is provided with a flange ring and is fastened to the outer walls of the upper box body and the lower box body through pins. The first plug and the second plug are used for replacing the first exhaust pipe and the second exhaust pipe to plug the first ventilation hole and the second ventilation hole, so that casting liquid is prevented from entering the first ventilation hole and the second ventilation hole in the middle period of casting, and casting defects caused by the fact that the first ventilation hole and the second ventilation hole are formed are reduced.

In fact, the present invention aims to reduce the probability of the generation of defects in other parts by the reinforced exhaust of the first and second air vent channels, and to increase the tubular burr defects from the first and second air vent channels, which are easily handled at the time of shipment.

Preferably, the first heat-conducting piston and the second heat-conducting piston are piston bodies formed by penetrating arc-shaped heat-conducting aluminum strips in a cylinder made of polyfluoro plastics and processing joints through sealant, and one end of each arc-shaped heat-conducting aluminum strip is located in the gas chamber, and the other end of each arc-shaped heat-conducting aluminum strip is located in the liquid chamber. The first buffer tank and the second buffer tank are used for slowing down the jet force of gas in the gas pump, for example, when the first gas pump is inflated, the first heat-conducting piston rises to compress the upper organic gas, the first exhaust pipe is opened slowly, and the cavity is pressurized from the first exhaust pipe; when the air pressure of the first air pump is too high, the first heat-conducting piston is promoted to rise further, when the critical pressure value of the organic gas is reached, the organic gas is quickly changed into liquid, the first heat-conducting piston is caused to reach the highest position, and at the moment of the gas-liquid change, the first buffer tank can suck the gas part in the cavity to the first buffer tank, so that the too high air pressure in the cavity is avoided; at the moment of pouring, the first air pump exhausts air, the first heat-conducting piston is pushed and heated by the steeply increased internal pressure and high-temperature gas in the cavity, so that the critical pressure of the liquid in the first heat-conducting piston is increased and instantly changed into gas, and the gas in the first buffer tank is partially returned to the cavity, so that the unfavorable phenomena of sudden change of the internal pressure of the cavity, deformation of the sand core and the like caused by the sudden change of the internal pressure of the cavity are avoided; in the subsequent casting process, the temperature and pressure change in the cavity is small, and the first exhaust pipe can be drawn away, so that the exhaust of the cavity passes through other exhaust pinholes or exhaust risers through the pores in the sand core and keeps constant pressure with the atmosphere.

Preferably, the volatile organic gas filled in the liquid chamber of the first buffer tank is any one of diethyl ether, acetone, ethanol and n-butane, and the organic gas has low critical pressure and low toxicity, so that the instant temperature difference and pressure difference in the cavity can be absorbed, the buffer capacity is improved, and the deformation of the cavity caused by overlarge airflow impact is avoided.

The invention also provides a use method of the exhaust structure in the casting sand core cavity, which comprises the following steps:

a. before casting liquid is poured, a first exhaust pipe and a second exhaust pipe are respectively arranged in a first vent hole and a second vent hole, a funnel plug of a casting head is opened, a first air pump and a second air pump are started, the flux of the first exhaust pipe and the flux of the second exhaust pipe are both 0.1-0.15T, the first exhaust pipe and the second exhaust pipe are blown oppositely, then the casting head is closed, when the air pressure in a first buffer tank and a second buffer tank is 0.3-0.35MPa, the first air pump and the second air pump are stopped, and a pipeline valve between the first air pump and the first buffer tank and a pipeline valve between the second air pump and the second buffer tank are closed;

b. when the casting liquid is poured, slightly deflating, opening the first air pump and the second air pump, simultaneously pumping out air in the sand core cavity by the first exhaust pipe and the second exhaust pipe, wherein the flux of the first exhaust pipe and the flux of the second exhaust pipe are both 0.03-0.05T, when the casting liquid occupies 1/3 of the cavity, rapidly pumping out the first exhaust pipe and the second exhaust pipe, and plugging the first ventilation channel and the second ventilation channel by the first plug and the second plug, wherein the pouring is not stopped until the pouring is finished.

Compared with the prior art, the invention has the beneficial effects that:

the novel exhaust structure is provided for overcoming the defect that the structure of the cavity is easily damaged due to unstable pressure in the cavity in the initial stage of sand casting pouring, the cavity is connected with the compression of organic gas and gas-liquid change through the heat-conducting piston cylinder, so that the temperature and the pressure in the cavity in the initial stage of pouring are suddenly increased, the impact force of air flow on the cavity is greatly reduced through the buffering of the buffer tank, the structural damage of the cavity in the existing exhaust process is avoided, and the generation of surface defects of a casting is reduced.

Drawings

FIG. 1 is a schematic structural view of an air venting structure in a casting sand core cavity according to the present invention;

in the figure: the device comprises an upper box body 1, a lower box body 2, a first ventilation hole channel 3, a second ventilation hole channel 4, a first exhaust pipe 5, a first buffer tank 6, a first heat-conducting piston 7, a first inflating valve 8, a first air pump 9, a second exhaust pipe 10, a second buffer tank 11, a second heat-conducting piston 12, a second inflating valve 13, a second air pump 14, a casting head 15, a funnel plug 16, a first plug 17 and a second plug 18.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to fig. 1, a first ventilation hole 3 and a second ventilation hole 4 are arranged at the contact surface of a sand core of an upper box body 1 and a lower box body 2, the first ventilation hole 3 consists of a semicircular groove arranged on the bottom surface of the sand core of the upper box body 1 and a semicircular groove arranged on the top surface of the sand core of the lower box body 2, the second ventilation hole 4 consists of another semicircular groove arranged on the bottom surface of the sand core of the upper box body 1 and another semicircular groove arranged on the top surface of the sand core of the lower box body 2, and the first ventilation hole 3 and the second ventilation hole 4 are both horizontally arranged and are on the same straight line; a first exhaust pipe 5 penetrates through the first vent hole 3, one end of the first exhaust pipe 5 extends into the sand core cavity, the other end of the first exhaust pipe 5 extends out of the sand core cavity and is connected with a first buffer tank 6, a first heat-conducting piston 7 is hermetically sleeved in the first buffer tank 6, the first buffer tank 6 is split into a gas chamber and a liquid chamber by the first heat-conducting piston 7, volatile organic gas is filled in the liquid chamber, a first air valve nozzle 8 is arranged at the top of the outer side wall of the first buffer tank 6, the first exhaust pipe 5 is connected to the lower position of the outer side wall of the first buffer tank 6, the vertical distance from the first exhaust pipe 5 to the bottom wall of the first buffer tank 6 is smaller than the thickness of the first heat-conducting piston 7, the bottom wall of the first buffer tank 6 is connected with a first air pump 9 through a pipeline, and an outlet at the other end; a second exhaust pipe 10 penetrates through the second vent channel 4, one end of the second exhaust pipe 10 extends into the sand core cavity, the other end of the second exhaust pipe 10 extends out of the sand core cavity and is connected with a second buffer tank 11, a second heat-conducting piston 12 is hermetically sleeved in the second buffer tank 11, the second buffer tank 11 is split into a gas chamber and a liquid chamber by the second heat-conducting piston 12, volatile organic gas is filled in the liquid chamber, a second valve 13 is arranged at the top of the outer side wall of the second buffer tank 11, a second air pump 14 is connected to the lower part of the outer side wall of the second buffer tank 11 through a pipeline, the vertical distance between the pipeline communicated with the second buffer tank 11 and the bottom wall of the second buffer tank 11 is smaller than the thickness of the second heat-conducting piston 12, an outlet at the other end of the second air pump 9 is communicated with the atmosphere, and the second exhaust pipe 10 is connected to the bottom wall of the; a casting head 15 is arranged on the top surface of the sand core of the upper box body 1, the top end opening of the casting head 15 is funnel-shaped, and a funnel plug 16 is sleeved at the top end opening of the casting head 15.

Referring to fig. 1, the inner walls of the first ventilation channel 3 and the second ventilation channel 4 are coated with paint, when the first exhaust pipe 5 and the second exhaust pipe 10 are drawn out, a first plug 17 is sleeved in the first ventilation channel 3, a second plug 18 is sleeved in the second ventilation channel 4, one end of each of the first plug 17 and the second plug 18 is flush with the inner wall of the cavity, and the other end of each of the first plug 17 and the second plug 18 is provided with a flange ring and is fastened to the outer walls of the upper box body 1 and the lower box body 2 through pins. The first plug 17 and the second plug 18 are used for replacing the first exhaust pipe 5 and the second exhaust pipe 10 to plug the first vent hole 3 and the second vent hole 4, so that casting liquid is prevented from entering the first vent hole 3 and the second vent hole 4 in the middle period of casting, and casting defects caused by the fact that the first vent hole 3 and the second vent hole 4 are formed are reduced. In fact, the present invention aims to reduce the probability of the formation of defects in other parts by the enhanced exhaust of the first and second air ducts 3 and 4, and to increase the possibility of tubular burr defects at the first and second air ducts 3 and 4, which are easily handled at the time of shipment.

Referring to fig. 1, the first heat conducting piston 7 and the second heat conducting piston 12 are piston bodies formed by penetrating arc-shaped heat conducting aluminum strips in a cylinder made of fluoroplastic and processing seams through sealant, and one end of each arc-shaped heat conducting aluminum strip is located in the gas chamber while the other end is located in the liquid chamber. The first buffer tank 6 and the second buffer tank 11 are used for slowing down the jet force of the gas in the gas pump, for example, when the first gas pump 9 is inflated, the first heat-conducting piston 7 rises to compress the upper organic gas, the first exhaust pipe 5 is slowly opened, and the cavity is pressurized from the first exhaust pipe 5; when the air pressure of the first air pump 9 is too high, the first heat-conducting piston 7 is promoted to further rise, when the critical pressure value of the organic gas is reached, the organic gas is quickly changed into liquid, so that the first heat-conducting piston 7 reaches the highest position, and at the moment of the gas-liquid change, the first buffer tank 6 can suck the gas part in the cavity to the first buffer tank 6, so that the too high air pressure in the cavity is avoided; at the moment of pouring, the first air pump 9 exhausts air, the first heat-conducting piston 7 is pushed and heated by the steeply increased internal pressure and high-temperature gas in the cavity, so that the critical pressure of the liquid in the first heat-conducting piston 7 is increased and instantly changed into gas, and the gas in the first buffer tank 6 is partially returned to the cavity, so that the unfavorable phenomena of sudden change of the internal pressure of the cavity, deformation of a sand core and the like caused by the sudden change of the internal pressure of the cavity are avoided; in the subsequent casting process, the temperature and pressure change in the cavity is small, and the first exhaust pipe 5 can be drawn away, so that the exhaust of the cavity passes through the fine holes in the sand core and other exhaust pinholes or exhaust risers to keep constant pressure with the atmosphere.

Referring to fig. 1, the volatile organic gas filled in the liquid chamber of the first buffer tank 6 is any one of diethyl ether, acetone, ethanol and n-butane, and the organic gas has low critical pressure and low toxicity, so that the absorption of instant temperature difference and pressure difference in the cavity is facilitated, the buffer capacity is improved, and the deformation of the cavity caused by overlarge airflow impact is avoided.

An example of the use of the invention is as follows:

a. before casting liquid is poured, a first exhaust pipe 5 and a second exhaust pipe 10 are respectively arranged in a first vent hole channel 3 and a second vent hole channel 4, a funnel plug 16 of a casting head 15 is opened, a first air pump 9 and a second air pump 14 are started, the flux of the first exhaust pipe 5 and the flux of the second exhaust pipe 10 are both 0.135T, the first exhaust pipe 5 and the second exhaust pipe 10 are blown oppositely by air flow, then the casting head 15 is closed, when the air pressure in a first buffer tank 6 and a second buffer tank 11 is 0.31MPa, the first air pump 9 and the second air pump 14 are stopped, and a pipeline valve between the first air pump 9 and the first buffer tank 6 and a pipeline valve between the second air pump 14 and the second buffer tank 11 are closed;

b. when the casting liquid is poured, slightly deflating, opening the first air pump 9 and the second air pump 14, enabling the first exhaust pipe 5 and the second exhaust pipe 10 to simultaneously exhaust the air in the sand core cavity, wherein the flux of the first exhaust pipe 5 and the flux of the second exhaust pipe 10 are both 0.042T, when the casting liquid occupies 1/3 of the cavity volume, quickly exhausting the first exhaust pipe 5 and the second exhaust pipe 10, and plugging the first vent channel 3 and the second vent channel 4 through the first plug 17 and the second plug 18, wherein the pouring is not stopped until the pouring is completed.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.