JP2012066289A - Sealing structure of reduced pressure casting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing structure of a reduced pressure casting apparatus sufficiently ensuring the lubrication of a slidable contact surface, and ensuring the durability and the sealability.SOLUTION: The reduced pressure casting apparatus includes a reduced pressure chamber for covering an open end on a counter die side of an injection sleeve in which a plunger rod 3 is disposed so as to reciprocate. The reduced pressure casting apparatus further includes: as a sealing structure coming in slidable contact with an outer circumference of the plunger rod 3 and sealing the slidable contact surface, a vacuum sealing member 14 which is disposed so as to be abutted on the slidable contact surface; and lubricant feed grooves 15, 16 which are formed in both atmosphere side and vacuum side of the vacuum sealing member 14 and feed lubricant to the slidable contact surface.

Description

  The present invention relates to a vacuum casting apparatus including a decompression chamber that covers an open end portion on the side opposite to a mold of an injection sleeve in which a plunger rod is reciprocally disposed, and is in sliding contact with the outer periphery of the plunger rod. The present invention relates to a seal structure of a vacuum casting apparatus that seals a sliding surface.

  As is well known, a vacuum casting apparatus that reduces casting defects such as air bubbles by reducing the pressure in the mold cavity during casting has been put into practical use. And in order to ensure the higher pressure reduction degree in a cavity, the pressure reduction casting apparatus like the patent document 1 provided with the pressure reduction chamber which covers the open end part by the side of the anti-mold of an injection sleeve is known. .

  FIG. 7 shows a configuration of a vacuum casting apparatus having such a vacuum chamber. As shown in the figure, an injection sleeve 52 is attached to a mold 51 provided with a cavity 50. The injection sleeve 52 is provided with a plunger tip 54 fixed to the tip of the plunger rod 53 so as to be able to reciprocate.

  A flange 55 is provided on the outer periphery of the injection sleeve 52. A decompression cup 56 is fixed to the opposite side of the flange 55 from the mold. The flange 55 and the decompression cup 56 define a decompression chamber 57 that covers the end of the injection sleeve 52 on the side opposite to the mold.

  The cavity 50 and the decompression chamber 57 are connected to a vacuum tank 59 and a vacuum pump 60 via a valve 58. Then, the vacuum tank 59 decompressed by the vacuum pump 60 is connected to the cavity 50 and the decompression chamber 57 by opening the valve 58 so that the cavity 50 and the decompression chamber 57 are decompressed.

  In such a reduced pressure casting apparatus, in order to ensure the airtightness of the reduced pressure chamber 57, a seal structure that slides on the outer periphery of the plunger rod 53 and seals the sliding contact surface is required. 2. Description of the Related Art Conventionally, a seal structure described in Patent Document 2 is known as a seal structure that slides on the outer periphery of a shaft member attached to a vacuum vessel and seals the sliding contact surface.

  FIG. 8 shows the seal structure described in the document 2. As shown in the figure, in this seal structure, a holder 62 through which a shaft member 61 passes is attached to a vacuum vessel 63. Three seal members 64, 65, 66 are provided on the inner periphery of the holder 62 in order from the vacuum container 63 side. The seal members 64, 65, 66 seal the sliding surface between the inner periphery of the holder 62 and the outer periphery of the shaft member 61.

  On the inner periphery of the holder 62, between the two seal members 64 and 65 on the vacuum side, a grease reservoir groove 67 for storing vacuum grease as a lubricant is formed. Further, a vacuum exhaust groove 68 that is exhausted to a vacuum is formed on the inner periphery of the holder 62 and between the two seal members 65 and 66 on the atmosphere side.

JP 2008-93712 A Japanese Utility Model Publication No. 6-35737

  Even in such a conventional seal structure, if the movement of the shaft member 61 is limited, it can withstand practical use. However, in the vacuum casting apparatus as described above, the plunger rod 53, which is a shaft member, is operated at a high speed during casting, and the conventional seal structure described above maintains sufficient durability and sealability. It ’s gone.

  That is, in the above-described conventional seal structure, the grease stored in the grease storage groove 67 is sufficiently spread between the two seal members 64 and 65 on the vacuum side, but is blocked by the central seal member 65. For this reason, the sliding contact surface between the two seal members 65 and 66 on the atmosphere side is hardly spread. Therefore, in such a portion, the oil film is cut and lubrication between the sliding contact surfaces becomes insufficient, so that the seal member 66 and the like are damaged due to wear or the like. Therefore, in the conventional seal structure as described above, it is difficult to ensure sufficient durability and sealability in a vacuum casting apparatus in which the shaft member is operated at a high speed.

  The present invention has been made in view of such circumstances, and a problem to be solved by the present invention is to provide a seal for a reduced pressure casting apparatus in which the sliding surface can be sufficiently lubricated to ensure durability and sealability. To provide a structure.

  The invention according to claim 1 as a seal structure of a reduced pressure casting apparatus is a reduced pressure casting apparatus comprising a reduced pressure chamber covering an open end portion on the side opposite to the mold of an injection sleeve in which a plunger rod is reciprocally disposed. Therefore, the seal structure for sliding contact with the outer periphery of the plunger rod to seal the sliding contact surface is premised. And in order to solve the said subject, while providing the vacuum seal member arrange | positioned so that it may contact | abut to the said sliding contact surface, a lubricant is supplied to the sliding contact surface to both the atmosphere side and the vacuum side of the vacuum sealing member Each of the lubricant supply units is provided.

  In the seal structure configured as described above, the lubricant is supplied to the sliding contact surface on both the vacuum side and the atmosphere side of the vacuum seal member. Therefore, even if the vacuum seal member dams the lubricant, the lubricant can be distributed to both the vacuum side and the atmosphere side. Therefore, according to the above configuration, sufficient lubrication of the sliding contact surface can be obtained, and durability and sealing performance can be ensured.

  If a scraper is provided on the atmosphere side of the lubricant supply section on the atmosphere side and further on the vacuum side of the lubricant supply section on the vacuum side as described in claim 2, the sliding contact surface It becomes possible to prevent the intrusion of foreign matter into the body. Further, since the lubricant is blocked by the scraper, the lubricant does not flow out excessively from the lubricated portion. Further, since the outflow is suppressed, a high-pressure lubricant layer is formed on the sliding surface, so that it is difficult for foreign matter to enter the sliding surface and the seal portion.

  Further, as described in claim 3, when a clearance is provided on the outer periphery of the vacuum seal member and a lubricant is supplied to the clearance, the vacuum seal member floats with respect to the sliding contact surface. Uneven wear of the sliding contact surface can be prevented.

  In such a reduced-pressure casting apparatus, a high load is applied to the vertically upper portion of the sliding contact surface due to the weight of the members constituting the seal structure and the reduced-pressure chamber. For this reason, in such a seal structure, uneven wear tends to occur in a portion vertically above the sliding contact surface.

  In that respect, if the supply of the lubricant to the outer periphery of the vacuum seal member is performed from above in the vertical direction, the vacuum seal member is pushed down vertically by the pressure of the lubricant, and the reaction force Thus, the entire seal structure is lifted vertically upward. For this reason, it is possible to reduce the load acting on the vertically upper portion of the slidable contact surface and suppress uneven wear of the slidable contact surface.

  Further, according to claim 5, the lubricant supply section is configured as a groove formed on the sliding contact surface, and the groove is formed so that the groove width increases from the vertically downward direction to the vertically upward direction. The uneven wear of the sliding contact surface can be suppressed. In this case, the force corresponding to the supply pressure of the lubricant is increased in the vertically upper portion where the groove width is wide, and is decreased in the vertically lower portion where the groove width is narrow. Therefore, the entire seal structure is pushed up vertically, and the load acting on the vertically upper portion of the sliding contact surface is reduced. Therefore, even in the configuration of the fifth aspect, it is possible to suppress uneven wear of the sliding contact surface.

Sectional drawing which shows the side cross-sectional structure of the injection sleeve of the pressure reduction casting apparatus which becomes the application object about one Embodiment of this invention, a plunger rod, and its peripheral part. Sectional drawing which shows the side part cross-section of the seal structure of the embodiment. Sectional drawing which expands and shows the peripheral part of the vacuum seal member of the seal structure of the embodiment. Sectional drawing which shows the cross-sectional structure in the axial orthogonal surface of the vacuum seal member periphery part of the seal structure of the embodiment. The perspective view which shows the formation aspect of the lubricant supply groove | channel of the seal structure of the embodiment. The figure which shows typically the effect | action aspect of the lubricant supply force around the plunger rod in the same embodiment. The schematic diagram which shows the structure of the conventional pressure reduction casting apparatus typically. Sectional drawing which shows the cross-section of the conventional seal structure.

Hereinafter, an embodiment in which a seal structure of a vacuum casting apparatus according to the present invention is embodied will be described in detail with reference to FIGS.
The reduced pressure casting apparatus to which the seal structure of the present embodiment is applied has basically the same configuration as the conventional reduced pressure casting apparatus shown in FIG. 7 except for the seal structure. That is, the decompression casting apparatus to which the present embodiment is applied also has an injection sleeve attached to a mold provided with a cavity, and a plunger tip disposed in the injection sleeve so as to be able to reciprocate is fixed to the tip. Provided with a plunger rod. Further, a decompression cup is provided, whereby a decompression chamber is formed to cover the end of the injection sleeve on the side opposite to the mold.

  FIG. 1 shows a side cross-sectional structure of an injection sleeve, a plunger rod, and a peripheral portion of a reduced pressure casting apparatus to which the present embodiment is applied. As shown in the figure, a pouring port 2 is formed on the side opposite to the mold (right side in the figure) of the injection sleeve 1 formed in a substantially circular tube shape. Inside the injection sleeve 1, a plunger tip 4 is fixed to the tip of the plunger rod 3 and reciprocally moved so as to press the molten metal poured from the pouring port 2 into the mold cavity. ing.

  A circular pipe-shaped decompression cup 5 is disposed around the end of the injection sleeve 1 on which the pouring port 2 is formed on the side opposite to the mold side. On the side of the pressure reducing cup 5 opposite to the mold, a seal portion 6 is fixed as a seal structure that slidably contacts the plunger rod 3 and seals the slidable contact surface. The decompression cup 5 and the seal portion 6 define an airtight decompression chamber 17.

  FIG. 2 shows a side sectional structure of the seal portion 6. As shown in the figure, the seal portion 6 includes a vacuum side scraper presser 7, a vacuum side copper bush 8, a seal presser 9, and an atmosphere side, each formed in a substantially annular shape in order from the vacuum side (left side in the figure) A copper bush 10 and an atmosphere side scraper presser 11 are provided.

  Further, the vacuum side scraper 12 is sandwiched between the atmosphere side copper bush 10 and the atmosphere side scraper retainer 11 in a form sandwiched between the vacuum side scraper retainer 7 and the vacuum side copper bush 8. Atmosphere side scrapers 13 are respectively provided. These scrapers prevent foreign matter from entering the sliding contact surfaces of the vacuum side copper bush 8 and the atmospheric side copper bush 10 and the plunger rod 3.

  Further, a vacuum seal member 14 formed in a substantially annular shape is disposed on the inner periphery of the seal retainer 9 in a form sandwiched between the vacuum side copper bush 8 and the atmosphere side copper bush 10. The vacuum seal member 14 is in close contact with the outer periphery of the plunger rod 3 by its own elasticity, thereby sealing the sliding contact surface between the seal portion 6 and the plunger rod 3.

  In the seal structure of the present embodiment, lubricant supply grooves 15 and 16 as lubricant supply portions are formed on the inner periphery of the vacuum side copper bush 8 and the atmosphere side copper bush 10. These lubricant supply grooves 15 and 16 are formed so as to go around the inner circumferences of the vacuum-side copper bush 8 and the atmosphere-side copper bush 10. The lubricant supply grooves 15 and 16 are supplied with vacuum grease as a lubricant from the outside.

  In this embodiment, the lubricant is supplied to both the vacuum side and the atmosphere side of the vacuum seal member 14. Therefore, even if the vacuum seal member 14 blocks the lubricant, the lubricant can be spread over both the vacuum side and the atmosphere side. Therefore, as shown in the figure, an oil film L is formed on both the sliding contact surface between the vacuum side copper bush 8 and the plunger rod 3 and the sliding contact surface between the atmosphere side copper bush 10 and the plunger rod 3. As a result, sufficient lubrication of the sliding contact surface can be obtained.

  FIG. 3 is an enlarged view of the peripheral portion of the vacuum seal member 14. As shown in the figure, a slight clearance is formed between the outer periphery of the vacuum seal member 14 and the inner periphery of the seal retainer 9. The vacuum grease is also supplied to the clearance. The supply of the vacuum grease to the outer periphery of the vacuum seal member 14 is performed from vertically above.

  In this embodiment, as shown in FIG. 4, the vacuum seal member 14 receives a load in a direction in which the vacuum seal member 14 is pushed down vertically by a force corresponding to the supply of the vacuum grease. On the other hand, the seal presser 9 receives a load in the direction of pushing upward vertically by the reaction force. The seal portion 6 receives the load in the vertically downward direction due to the weight of the seal portion 6 and the decompression cup 5 fixed to the seal portion 6, and uneven wear tends to occur in the vertically upward portion of the plunger rod 3. In that respect, in the seal structure of the present embodiment, the seal presser 9 and, consequently, the entire seal portion 6 are pushed up vertically by the supply force of the vacuum grease to the outer periphery of the vacuum seal member 14 as described above. It is possible to reduce the load in the vertically downward direction by suppressing uneven wear.

Further, in the present embodiment, the above-described uneven wear can be suppressed also by devising the shape of the lubricant supply grooves 15 and 16.
FIG. 5 shows how the lubricant supply grooves 15 and 16 around the plunger rod 3 are formed in the present embodiment. As shown in the figure, in the present embodiment, the lubricant supply grooves 15 and 16 are formed such that the groove width increases from the vertically downward direction to the vertically upward direction. In this embodiment, as shown in FIG. 6, the force corresponding to the supply pressure of the vacuum grease to the lubricant supply grooves 15 and 16 becomes large in the vertically upper portion where the groove width is wide, and the groove width is narrow. It becomes smaller in the vertically lower part. Therefore, due to the difference in force according to the supply pressure of the vacuum grease, the entire seal portion 6 is lifted vertically upward, and the load acting on the vertically upward portion of the sliding contact surface is reduced. Therefore, the uneven wear of the sliding contact surface is also suppressed by the shape of the lubricant supply grooves 15 and 16.

According to the seal structure of the vacuum casting apparatus of the present embodiment described above, the following effects can be obtained.
(1) The seal structure of the present embodiment is a reduced pressure casting apparatus including a reduced pressure chamber 17 that covers an open end portion on the side opposite to the mold of the injection sleeve 1 in which the plunger rod 3 is reciprocally disposed. The plunger rod 3 is in sliding contact with the outer periphery of the plunger rod 3 to seal the sliding contact surface. In this embodiment, the vacuum seal member 14 is provided so as to come into contact with the sliding contact surface, and the lubricant is applied to the sliding contact surface on both the atmosphere side and the vacuum side of the vacuum seal member 14. Lubricant supply grooves 15 and 16 are provided as lubricant supply parts to be supplied.

  In the seal structure configured as described above, the lubricant is supplied to the sliding contact surface on both the vacuum side and the atmosphere side of the vacuum seal member 14. Therefore, even if the vacuum seal member 14 blocks the lubricant, the lubricant can be spread over both the vacuum side and the atmosphere side. Therefore, according to the present embodiment, sufficient lubrication of the sliding contact surface can be obtained, and durability and sealability can be ensured.

  (2) In the present embodiment, a sliding contact surface is formed on the vacuum side of the vacuum side copper bush 8 in which the lubricant supply groove 15 is formed and on the air side of the atmosphere side copper bush 10 in which the lubricant supply groove 16 is formed. A vacuum-side scraper 12 and an atmosphere-side scraper 13 are provided for preventing foreign substances from entering the air. Therefore, it is possible to effectively prevent foreign matter from entering the sliding contact surfaces of the vacuum side copper bush 8 and the atmosphere side copper bush 10 and the plunger rod 3. Further, since the vacuum grease is dammed by the vacuum side scraper 12 and the atmospheric side scraper 13, the vacuum grease does not flow out excessively from the lubricated portion. Further, since the outflow is suppressed, a layer of high-pressure vacuum grease is formed on the sliding surface, so that foreign matter is less likely to enter the sliding surface and the seal portion.

  (3) In this embodiment, a clearance is provided on the outer periphery of the vacuum seal member 14 and a lubricant is supplied to the clearance. Therefore, the vacuum seal member 14 floats with respect to the sliding contact surface, and uneven wear of the sliding contact surface can be suppressed.

  (4) In the present embodiment, the lubricant is supplied to the outer periphery of the vacuum seal member 14 from vertically above. In such a case, the vacuum seal member 14 is pushed down vertically by the supply force of the lubricant, and the entire seal structure is lifted vertically upward by the reaction force. Therefore, the load acting on the vertically upper portion of the sliding contact surface can be reduced by the weight of the seal portion 6 and the decompression cup 5, and uneven wear of the sliding contact surface can be suppressed.

  (5) In the present embodiment, the lubricant supply grooves 15 and 16 are formed so that the groove width increases from the vertically downward direction to the vertically upward direction. In such a case, the force corresponding to the supply pressure of the lubricant is increased in the vertically upper portion where the groove width is wide, and is decreased in the vertically lower portion where the groove width is narrow. Therefore, the entire seal portion 6 is pushed up vertically, and the load acting on the vertically upper portion of the sliding contact surface is reduced. Therefore, according to the present embodiment, the uneven wear of the sliding contact surface can be further suppressed.

In addition, the said embodiment can also be changed and implemented as follows.
In the above embodiment, the lubricant supply grooves 15 and 16 are formed so that the groove width increases as it goes from vertically downward to vertically upward. If uneven wear due to the weight of the seal portion 6 or the decompression cup 5 is not a problem, the lubricant supply grooves 15 and 16 may be formed in shapes other than those shapes.

  In the above embodiment, the lubricant is supplied to the outer periphery of the vacuum seal member 14 from vertically above. However, even if the lubricant is supplied to the outer periphery of the vacuum seal member 14 from a direction other than vertically above, if the clearance is provided on the outer periphery of the vacuum seal member 14 and the lubricant is supplied to the clearance, the vacuum seal is provided. Since the member 14 floats with respect to the sliding contact surface, uneven wear of the sliding contact surface can be suppressed to some extent.

  In the above embodiment, a clearance is provided on the outer periphery of the vacuum seal member 14 and a lubricant is supplied to the clearance. If the uneven wear of the sliding contact surface can be sufficiently suppressed without floating the vacuum seal member 14, the formation of the clearance on the outer periphery of the vacuum seal member 14 and the supply of the lubricant to the clearance are omitted. You may make it do.

  In the above-described embodiment, the sliding side is in contact with the vacuum side of the vacuum side copper bush 8 in which the lubricant supply groove 15 is formed and the atmospheric side of the atmosphere side copper bush 10 in which the lubricant supply groove 16 is formed. A vacuum-side scraper 12 and an atmosphere-side scraper 13 for preventing intrusion of foreign substances are provided. Of course, when the vacuum casting apparatus is used in a clean environment, when foreign matter does not enter the sliding surface, either one or both of the vacuum-side scraper 12 and the atmospheric-side scraper 13 are omitted. Anyway.

  DESCRIPTION OF SYMBOLS 1 ... Injection sleeve, 2 ... Pouring port, 3 ... Plunger rod, 4 ... Plunger tip, 5 ... Depressurization cup, 6 ... Seal part, 7 ... Vacuum side scraper presser, 8 ... Vacuum side copper bush, 9 ... Seal presser DESCRIPTION OF SYMBOLS 10 ... Atmosphere side copper bush, 11 ... Atmosphere side scraper press, 12 ... Vacuum side scraper, 13 ... Atmosphere side scraper, 14 ... Vacuum seal member, 15 ... Lubricant supply groove, 16 ... Lubricant supply groove, 17 ... Depressurization 50, cavity, 51 ... mold, 52 ... injection sleeve, 53 ... plunger rod, 54 ... plunger tip, 55 ... flange, 56 ... decompression cup, 57 ... decompression chamber, 58 ... valve, 59 ... vacuum Tank, 60 ... Vacuum pump, 61 ... Shaft material, 62 ... Holder, 63 ... Vacuum container, 64 ... Seal member, 65 ... Seal member, 66 ... Seal member, 67 ... Grease Scan reservoir groove, 68 ... vacuum exhaust groove.

Claims (5)

A decompression casting apparatus comprising a decompression chamber that covers an open end portion on the side opposite to the mold of an injection sleeve in which a plunger rod is reciprocally disposed, and is in sliding contact with the outer periphery of the plunger rod. A sealing structure for performing
A vacuum seal member disposed so as to contact the sliding contact surface;
A seal structure for a vacuum casting apparatus, characterized in that a lubricant supply section for supplying a lubricant to the sliding contact surface is provided on both the atmosphere side and the vacuum side of the vacuum seal member. 2. The vacuum casting apparatus according to claim 1, wherein scrapers are respectively provided on the atmosphere side of the lubricant supply unit on the atmosphere side and on the vacuum side of the lubricant supply unit on the vacuum side. Seal structure. The seal structure of the vacuum casting apparatus according to claim 1 or 2, wherein a clearance is provided on an outer periphery of the vacuum seal member, and the lubricant is supplied to the clearance. The seal structure of the vacuum casting apparatus according to claim 3, wherein the lubricant is supplied to the outer periphery of the vacuum seal member from vertically above. The lubricant supply section is a groove formed on the sliding contact surface, and the groove is formed such that the groove width increases from vertically downward to vertically upward. The seal structure of the vacuum casting apparatus of any one of -4.

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