The disclosure of Japanese Patent Application No. 2018-178566 filed on Sep. 25, 2018 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
The present disclosure relates to an oil separating device and a vacuum die casting apparatus.
As one of metal mold casting methods, a die casting method in which molten metal is forcibly inserted into a mold and with which a cast can be manufactured at a high dimensional precision in a short time has been known. In the case of the die casting method, there is a possibility of a defect due to air entrapment or a mold corner portion not filled with molten metal since the molten metal is forcibly inserted into the mold at a high speed. Therefore, a vacuum die casting method, in which molten metal is injected to fill a mold after air present in a cavity in the mold is sucked by a vacuum pump in advance such that the pressure in the cavity is reduced and the cavity enters a vacuum state, has been proposed. In the case of the vacuum die casting method, the flowability of the molten metal is improved and running properties are improved since resistance is small. In addition, since a gas is sucked out from the cavity, a casting defect called a blow hole or blister which is caused by gas entrapment is also suppressed.
In many of such die casting apparatuses, lubricant is supplied into an injection sleeve through a molten metal supply port before molten metal is poured such that the movement of a plunger tip in the injection sleeve is improved. A component of the lubricant is, for example, any of oxidized polyethylene, vegetable oil wax, graphite wax, alkamide, silicon wax, and solid lubricant or a combination thereof.
Japanese Unexamined Patent Application Publication No. 11-057968 (JP 11-057968 A) discloses a configuration in which a filter is provided in an intake path through which a vacuum die casting apparatus and a vacuum pump communicate with each other. The filter is provided with a filtering medium formed of steel wool. Foreign substances such as metal powder generated in the vacuum die casting apparatus are collected by the filtering medium of the filter.
Meanwhile, when lubricant is supplied into an injection sleeve, the lubricant is combusted due to the heat of the injection sleeve and a combustion gas is generated. The generated combustion gas is sucked by a vacuum pump via a cavity. Here, oil contained in the combustion gas has a property of being likely to adhere and accumulate since the oil becomes highly adhesive when there is a decrease in pressure and temperature. In a case where the oil adheres to a pressure reducing system or the like and accumulates thereon, there is a possibility that the degree of cavity pressure reduction is deteriorated.
Collecting the oil in the combustion gas is not mentioned in JP 11-057968 A.
The present disclosure provides an oil separating device that is provided in an intake path, through which a cavity in a vacuum die casting apparatus and an intake port of a vacuum pump communicate with each other, and that separates oil from a gas flowing through the intake path and a vacuum die casting apparatus.
A first aspect of the present disclosure relates to an oil separating device. The oil separating device is provided in an intake path through which a cavity of a mold and an intake port of a vacuum pump communicate with each other and the oil separating device is configured to separate oil from a gas flowing through the intake path. The oil separating device includes a first tubular body and a spiral plate accommodated in the first tubular body. The spiral plate and the first tubular body define a spiral flow path.
According to the first aspect of the present disclosure, it is possible to separate the oil from the gas since the oil contained in the gas is collected by the first tubular body and the spiral plate due to an inertial force.
In the oil separating device according to the first aspect, the spiral plate may be configured to be inserted into and extracted from the first tubular body.
According to the first aspect of the present disclosure, it is possible to easily recover oil adhering to the first tubular body and the spiral plate.
The oil separating device according to the first aspect may further include a second tubular body and a plurality of baffle plates accommodated in the second tubular body. The baffle plates may be arranged in a longitudinal direction of the second tubular body and the second tubular body and the baffle plates may define a zigzag flow path.
According to the first aspect of the present disclosure, it is possible to separate oil from the gas since the oil contained in the gas is collected by the baffle plates due to an inertial force.
In the oil separating device according to the first aspect, the second tubular body may be a rectangular tubular body, the second tubular body may be provided with a first side plate and a second side plate facing each other, one of two baffle plates adjacent to each other in the longitudinal direction of the second tubular body may be fixed to the first side plate, the other of the two baffle plates adjacent to each other in the longitudinal direction of the second tubular body may be fixed to the second side plate, and the first side plate and the second side plate may be configured to be attached to and detached from each other.
According to the first aspect of the present disclosure, it is possible to easily recover oil adhering to the two adjacent baffle plates since the two adjacent baffle plates are separated from each other when the first side plate is detached from the second side plate.
In the oil separating device according to the first aspect, each of the baffle plates may be provided with a ventilation portion and the ventilation portions of two baffle plates adjacent to each other in the longitudinal direction of the second tubular body may be disposed at different positions as seen in the longitudinal direction of the second tubular body.
According to the first aspect of the present disclosure, the zigzag flow path is formed with a simple configuration.
In the oil separating device according to the first aspect, two baffle plates adjacent to each other in the longitudinal direction of the second tubular body may be configured to become closer to each other toward a downstream side of a flow path defined by the two baffle plates.
According to the first aspect of the present disclosure, it is possible to make the flow speed of the gas greater toward a downstream side of a flow path defined by the two baffle plates.
The oil separating device according to the first aspect may further include a second baffle plate that is disposed between two baffle plates adjacent to each other in the longitudinal direction of the second tubular body and divides a space defined by the two baffle plates.
According to the first aspect of the present disclosure, a flow path defined by the two baffle plates becomes more complicated.
A second aspect of the present disclosure relates to a vacuum die casting apparatus including a mold, a vacuum pump, an intake path, and an oil separating device.
A cavity of the mold and an intake port of the vacuum pump communicate with each other through the intake path and the oil separating device is configured to separate oil from a gas flowing through the intake path. The oil separating device is disposed in the intake path. The oil separating device includes a first tubular body and a spiral plate accommodated in the first tubular body and the spiral plate and the first tubular body define a spiral flow path in the oil separating device.
According to the aspects of the present disclosure, it is possible to separate oil from a gas flowing through an intake path with an oil separating device provided in the intake path through which a cavity of a vacuum die casting apparatus and an intake port of a vacuum pump communicate with each other.
Features, advantages, and technical and industrial significance of exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:
Hereinafter, a preferred embodiment of the present disclosure will be described.
The mold 3 includes a fixed mold 7 and a movable mold 8. When the mold 3 is clamped, the cavity 2 is formed between the fixed mold 7 and the movable mold 8. In addition, a gate 9 and a runner 10 are formed in the mold 3 when the mold 3 is in a clamped state.
The injection device 5 includes an injection sleeve 11, a plunger tip 12, a rod 13, and plunger driving means (not shown).
The injection sleeve 11 communicates with the runner 10 of the mold 3 and is coupled to the fixed mold 7. A molten metal supply port 14 for pouring the molten metal 4 into the injection sleeve 11 is formed in a rear end of the injection sleeve 11.
The plunger tip 12 is disposed in the injection sleeve 11 such that the plunger tip 12 can freely move forward and backward inside the injection sleeve 11 along a longitudinal direction of the injection sleeve 11. A lubricant that improves sliding between the injection sleeve 11 and the plunger tip 12 is applied onto an outer peripheral surface of the plunger tip 12. A component of the lubricant is, for example, any of oxidized polyethylene, vegetable oil wax, graphite wax, alkamide, silicon wax, and solid lubricant or a combination thereof.
The plunger driving means drives the plunger tip 12 via the rod 13 connected to the plunger tip 12 such that the plunger tip 12 moves forward and backward.
The vacuum suction device 6 includes a vacuum pump 20, a vacuum tank 21, a pressure reducing valve 22, and an oil separating device 23.
The vacuum pump 20 and the vacuum tank 21 communicate with each other through a pipe 24.
The vacuum tank 21 and the pressure reducing valve 22 communicate with each other through a pipe 25.
The pressure reducing valve 22 and the oil separating device 23 communicate with each other through a pipe 26.
The oil separating device 23 and the cavity 2 of the mold 3 communicate with each other through a pipe 27.
The pipe 24, the pipe 25, the pipe 26, and the pipe 27 constitute an intake path 30 through which the cavity 2 of the mold 3 and an intake port 20a of the vacuum pump 20 communicate with each other. Accordingly, it is possible to say that the oil separating device 23 is provided in the intake path 30.
The oil separating device 23 is a device that separates oil from a gas flowing through the intake path 30. The configuration of the oil separating device 23 will be described in detail later.
In the case of the above-described configuration, a negative pressure is supplied from the vacuum tank 21 to the cavity 2 when the pressure reducing valve 22 is opened.
Next, an operation of the vacuum die casting apparatus 1 will be schematically described.
First, the lubricant is applied to the outer peripheral surface of the plunger tip 12. Next, a predetermined amount of molten metal 4 is poured into the injection sleeve 11 through the molten metal supply port 14. Then, the plunger tip 12 is driven to move forward. When the plunger tip 12 moves forward beyond the position of the molten metal supply port 14, the pressure reducing valve 22 is opened such that a gas in the cavity 2 is vacuum-sucked. Then, the plunger tip 12 is caused to move further forward such that the molten metal 4 is injected into the cavity 2 through the runner 10 and the gate 9.
At this time, the lubricant applied onto the outer peripheral surface of the plunger tip 12 is combusted due to the heat of the molten metal 4. Therefore, a combustion gas containing oil is generated in the plunger tip 12. The combustion gas in the plunger tip 12 is sucked by the vacuum suction device 6 and is guided to the oil separating device 23 through the cavity 2 and the pipe 27. Then, the oil contained in the combustion gas is separated from the combustion gas by the oil separating device 23 and is collected by the oil separating device 23. Accordingly, the pipe 26, the pressure reducing valve 22, the pipe 25, the vacuum tank 21, the pipe 24, and the vacuum pump 20 which are disposed downstream of the oil separating device 23 can be kept clean.
Next, the oil separating device 23 will be described in detail.
As shown in
The direction to the upper side is a specific example of a first direction. The direction to the lower side is a specific example of a second direction. The direction to the front side is a specific example of a third direction. The direction to the rear side is a specific example of a fourth direction. The direction to the right side is a specific example of a fifth direction. The direction to the left side is a specific example of a sixth direction.
As shown in
As shown in
The front surface panel 36 shown in
As shown in
The helical trap 37 is disposed on a left side of the internal space of the box body 35. The labyrinth trap 38 is disposed on a right side of the internal space of the box body 35. The V-shaped bottom plate 39 is disposed on a lower side of the internal space of the box body 35.
The V-shaped bottom plate 39 includes a right inclined plate 39a that is downwardly inclined toward a left side from the right side plate 42d and a left inclined plate 39b that is downwardly inclined toward a right side from the left side plate 42e. That is, the V-shaped bottom plate 39 extends from the right side plate 42d to the left side plate 42e and is folded to protrude downward.
As shown in
Note that, the spiral plate 51 has good maintenance properties since the spiral plate 51 is configured to be able to be inserted into and extracted from the tubular body 50. In addition, when a positioning plate 53 provided at an upper end of the spiral plate 51 is engaged with the intake port side joint 40, the position of the spiral plate 51 relative to the tubular body 50 in a longitudinal direction of the tubular body 50 is determined.
As shown in
The tubular body 60 is formed by the right side plate 42d, a right portion of the rear plate 42c (refer to
The horizontal baffle plates 61 are arranged at approximately equal intervals in the vertical direction. The horizontal baffle plates 61 extend to the right side plate 42d from the central partition wall 63. The horizontal baffle plates 61 and the perpendicular baffle plates 62 are alternately arranged in the vertical direction. Hereinafter, for the sake of convenience of the description, the horizontal baffle plates 61 will be referred to as horizontal baffle plates 61a, 61b, 61c, 61d, 61e, 61f in order from the bottom to the top as shown in
The perpendicular baffle plate 62a is disposed between the horizontal baffle plate 61a and the horizontal baffle plate 61b.
The perpendicular baffle plate 62b is disposed between the horizontal baffle plate 61b and the horizontal baffle plate 61c.
The perpendicular baffle plate 62c is disposed between the horizontal baffle plate 61c and the horizontal baffle plate 61d.
The perpendicular baffle plate 62d is disposed between the horizontal baffle plate 61d and the horizontal baffle plate 61e.
The perpendicular baffle plate 62e is disposed between the horizontal baffle plate 61e and the horizontal baffle plate 61f.
The baffle plates 61a, 61c, 61e are flat plates that are downwardly inclined toward a right side. Meanwhile, the horizontal baffle plates 61b, 61d, 61f are flat plates that are upwardly inclined toward the right side.
A cutout 64 is formed in a right rear end of each of the horizontal baffle plates 61a, 61c, 61e. Similarly, a cutout 65 is formed in a left rear end of each of the horizontal baffle plates 61b, 61d, 61f.
The perpendicular baffle plate 62a is a flat plate parallel to the right side plate 42d and extends to the horizontal baffle plate 61b from the horizontal baffle plate 61a. The perpendicular baffle plate 62a is disposed to divide a space between the horizontal baffle plate 61a and the horizontal baffle plate 61b in a lateral direction. A cutout 66 is formed in a front upper end of the perpendicular baffle plate 62a.
The perpendicular baffle plate 62b is a flat plate parallel to the right side plate 42d and extends to the horizontal baffle plate 61c from the horizontal baffle plate 61b. The perpendicular baffle plate 62b is disposed to divide a space between the horizontal baffle plate 61b and the horizontal baffle plate 61c in the lateral direction. The cutout 66 is formed in a front upper end of the perpendicular baffle plate 62b.
The perpendicular baffle plate 62c is a flat plate parallel to the right side plate 42d and extends to the horizontal baffle plate 61d from the horizontal baffle plate 61c. The perpendicular baffle plate 62c is disposed to divide a space between the horizontal baffle plate 61c and the horizontal baffle plate 61d in the lateral direction. The cutout 66 is formed in a front upper end of the perpendicular baffle plate 62c.
The perpendicular baffle plate 62d is a flat plate parallel to the right side plate 42d and extends to the horizontal baffle plate 61e from the horizontal baffle plate 61d. The perpendicular baffle plate 62d is disposed to divide a space between the horizontal baffle plate 61d and the horizontal baffle plate 61e in the lateral direction. The cutout 66 is formed in a front upper end of the perpendicular baffle plate 62d.
The perpendicular baffle plate 62e is a flat plate parallel to the right side plate 42d and extends to the horizontal baffle plate 61f from the horizontal baffle plate 61e. The perpendicular baffle plate 62e is disposed to divide a space between the horizontal baffle plate 61e and the horizontal baffle plate 61f in the lateral direction. The cutout 66 is formed in a front upper end of the perpendicular baffle plate 62e.
In the case of the above-described configuration, as illustrated in
(1) The combustion gas discharged from the helical trap 37 flows into the labyrinth trap 38 through the cutout 63a of the central partition wall 63.
(2) The combustion gas passes through the cutout 64 of the horizontal baffle plate 61a and the cutout 66 of the perpendicular baffle plate 62a in this order and flows to the left side.
(3) The combustion gas passes through the cutout 65 of the horizontal baffle plate 61b and the cutout 66 of the perpendicular baffle plate 62b in this order and flows to the right side.
(4) The combustion gas passes through the cutout 64 of the horizontal baffle plate 61c and the cutout 66 of the perpendicular baffle plate 62c in this order and flows to the left side.
(5) The combustion gas passes through the cutout 65 of the horizontal baffle plate 61d and the cutout 66 of the perpendicular baffle plate 62d in this order and flows to the right side.
(6) The combustion gas passes through the cutout 64 of the horizontal baffle plate 61e and the cutout 66 of the perpendicular baffle plate 62e in this order and flows to the left side.
(7) The combustion gas passes through the cutout 65 of the horizontal baffle plate 61f, flows to the right side, and is discharged through the exhaust port 32.
In addition, the combustion gas passing through the cutout 64 of the horizontal baffle plate 61a collides with a lower surface of the horizontal baffle plate 61b due to an inertial force. Due to the above-described collision, oil contained in the combustion gas adheres to the lower surface of the horizontal baffle plate 61b and is collected.
Similarly, the combustion gas passing through the cutout 65 of the horizontal baffle plate 61b collides with a lower surface of the horizontal baffle plate 61c due to an inertial force. Due to the above-described collision, oil contained in the combustion gas adheres to the lower surface of the horizontal baffle plate 61c and is collected.
Similarly, the combustion gas passing through the cutout 64 of the horizontal baffle plate 61c collides with a lower surface of the horizontal baffle plate 61d due to an inertial force. Due to the above-described collision, oil contained in the combustion gas adheres to the lower surface of the horizontal baffle plate 61d and is collected.
Similarly, the combustion gas passing through the cutout 65 of the horizontal baffle plate 61d collides with a lower surface of the horizontal baffle plate 61e due to an inertial force. Due to the above-described collision, oil contained in the combustion gas adheres to the lower surface of the horizontal baffle plate 61e and is collected.
Similarly, the combustion gas passing through the cutout 64 of the horizontal baffle plate 61e collides with a lower surface of the horizontal baffle plate 61f due to an inertial force. Due to the above-described collision, oil contained in the combustion gas adheres to the lower surface of the horizontal baffle plate 61f and is collected.
In this manner, the combustion gas repeatedly collides with the horizontal baffle plates 61 in the zigzag flow path 67 of the labyrinth trap 38. Accordingly, oil contained in the combustion gas is effectively collected by the labyrinth trap 38.
In addition, since the perpendicular baffle plates 62 are provided in addition to the horizontal baffle plates 61, the combustion gas repeatedly collides with the perpendicular baffle plates 62 as well. Accordingly, oil contained in the combustion gas is more effectively collected by the labyrinth trap 38.
In addition, the cutout 64 or the cutout 65 formed in each horizontal baffle plate 61 is formed in the rear end of each horizontal baffle plate 61. Meanwhile, the cutout 66 formed in each perpendicular baffle plate 62 is formed in the front end of each perpendicular baffle plate 62. Therefore, the zigzag flow path 67 is a complicated flow path that is zigzag in the lateral direction and is zigzag in a front-rear direction. Accordingly, the number of times of collision between the combustion gas and the labyrinth trap 38 is increased and thus the oil collecting performance of the labyrinth trap 38 is significantly improved.
The helical trap 37 and the labyrinth trap 38 as described above are configured to actively cause the collision of the combustion gas by using the flow speed of the combustion gas. Therefore, the flow speed of the combustion gas in the oil separating device 23 is a significant factor for a collecting performance of the oil separating device 23. Therefore, the present inventors carried out fluid analysis (Computational Fluid Dynamics (CFD)) of the combustion gas in the oil separating device 23.
Next, a performance test of the oil separating device 23 will be reported.
The vacuum pump 81 is connected to the vacuum tank 82 via a pipe 88a. The vacuum tank 82 is connected to the ball valve 84 via a pipe 88b. The ball valve 84 is connected to the exhaust port 32 of the oil separating device 23 via a pipe 88c. The intake port 31 of the oil separating device 23 is connected to the rocket-shaped tubular body 86 via a pipe 88d.
In addition, the pipe 88b is provided with the pressure gauge 83. The pipe 88c is a translucent flexible pipe having a diameter of 25 millimeters. A portion of the pipe 88c is immersed in a coolant W in the water tank 85. The coolant W is maintained at a temperature of 10° C. or less. A semi-spherical recess portion 87a having a radius of 40 millimeters is formed on an upper surface of the mold 87. Note that, the capacity of the vacuum tank 82 is 30 liters.
With the above-described configuration prepared, first, the vacuum pump 81 is activated such that the gauge pressure of the vacuum tank 82 becomes equal to or lower than −96 kilopascals. Next, 0.5 grams of solid lubricant is placed on the recess portion 87a of the mold 87. Next, 50 grams of molten metal 4 (680° C.) of aluminum alloy (ADC12) is poured into the recess portion 87a of the mold 87. Accordingly, the solid lubricant is ignited and combusted and the recess portion 87a is covered with the rocket-shaped tubular body 86 to extinguish a fire. In this state, the ball valve 84 is opened for approximately three seconds and is closed thereafter. Then, a semi-spherical aluminum alloy is extracted from the recess portion 87a and a carbide remaining in the recess portion 87a is wiped out or the like to clean the recess portion 87a. A step from an operation of placing the solid lubricant on the recess portion 87a and to an operation of cleaning the recess portion 87a as described above was repeated 20 times.
Hereinabove, a preferred embodiment of the present disclosure has been described. The embodiment has features as follows.
As shown in
In addition, the spiral plate 51 is configured to be able to be inserted into and extracted from the tubular body 50. With the above-described configuration, it is possible to easily recover oil adhering to the tubular body 50 and the spiral plate 51 by extracting the spiral plate 51 from the tubular body 50.
In addition, as shown in
In addition, as shown in
Note that, a configuration in which one of two perpendicular baffle plates 62 adjacent to each other in the longitudinal direction of the tubular body 60 is fixed to the front surface panel 36 and the other of the two perpendicular baffle plates 62 is fixed to the rear plate 42c may also be adopted. With the above-described configuration, it is possible to easily recover oil adhering to two adjacent perpendicular baffle plates 62 since the two adjacent perpendicular baffle plates 62 are separated from each other when the front surface panel 36 is detached from the rear plate 42c (box body 35).
In the present embodiment, the horizontal baffle plate 61a, the perpendicular baffle plate 62b, the horizontal baffle plate 61c, the perpendicular baffle plate 62d, and the horizontal baffle plate 61e are fixed to the front surface panel 36 and the other horizontal baffle plates 61 and perpendicular baffle plates 62 are fixed to the rear plate 42c. With the above-described configuration, it is possible to easily recover oil adhering to two adjacent horizontal baffle plates 61 and two adjacent perpendicular baffle plates 62 since the two adjacent horizontal baffle plates 61 are separated from each other and the two adjacent perpendicular baffle plates 62 are separated from each other when the front surface panel 36 is detached from the rear plate 42c (box body 35).
In addition, as shown in
In addition, as shown in
In addition, as shown in
The vacuum die casting apparatus 1 is provided with the mold 3, the vacuum pump 20, and the oil separating device 23. According to the above-described configuration, it is possible to keep the vacuum pump 20 clean since oil in the combustion gas is collected in the oil separating device 23.
In the above-described embodiment, all of the box body 35, the front surface panel 36, the helical trap 37, the labyrinth trap 38, and the V-shaped bottom plate 39 are configured by using a metal plate which is excellent in corrosion resistance.
In addition, the present inventors consider that the helical trap 37 exhibits the collecting performance when the flow rate of the combustion gas is relatively small and the labyrinth trap 38 exhibits the collecting performance when the flow rate of the combustion gas is relatively large.
Hereinabove, the preferred embodiment of the present disclosure has been described. The embodiment can be modified as follows.
For example, an inner circumferential surface of the intake port 31 of the oil separating device 23 may be configured to become narrower toward a lower side and a baffle plate with which the combustion gas from the intake port 31 collides may be provided. In this case, since the combustion gas collides with the baffle plate at a high speed, oil in the combustion gas is effectively collected by the baffle plate.
In addition, the vacuum die casting apparatus 1 may be further provided with a heater that heats the pipe 27 shown in
In addition, the vacuum die casting apparatus 1 may be further provided with cooling means for cooling the oil separating device 23. With the above-described configuration, since oil in the combustion gas becomes highly adhesive in the oil separating device 23, the oil collecting performance of the oil separating device 23 is improved.
In addition, in
Number | Date | Country | Kind |
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2018-178566 | Sep 2018 | JP | national |