Spool Bush

Abstract

To enhance the cooling performance of a spool bush.SOLUTION: A spool bush 10 comprises an inner cylinder 11, an outer cylinder 12 that is a member separate from the inner cylinder 11, made immovable toward axial, one side lying downstream in a flow direction of a molten molding material and fitted over the inner cylinder 11, and an annular flange 13 that is a member separate respectively from the inner cylinder 11 and the outer cylinder 12 and contacts an end 44 on axial, the other side of the outer cylinder 12 from axial, the other side. The inner cylinder 11 has a mount portion 14 on which the flange 13 is mounted. The inner cylinder 11 is provided with a circumferential groove 15 extending along a circumferential direction in an outer peripheral surface 11a thereof, so that a cooling-liquid flow passage 20 is configured by an inner peripheral surface 12a of the outer cylinder 12 and the circumferential groove 15.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a spool bush.

Background Art

[0002] Patent Document 1 discloses a spool bush (pouring sleeve) provided in a molding die for casting. A flow path for passing a coolant is formed in the spool bush. In the spool bush, by enhancing the cooling performance on the pouring runner side, solidification of the molten metal in the pouring runner is promoted, and it is known that the casting cycle time is shortened.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the case of the spool bush described in Patent Document 1, as a flow path for passing a coolant, in addition to the circumferential flow path, a cooling hole extending from the flow path along the axial direction to the pouring runner side is formed, and a pipe is provided in the cooling hole. With this configuration, the cooling performance on the pouring runner side is enhanced, and solidification of the molten metal passing through the pouring runner is promoted.

[0005] As described above, various attempts have been made to shorten the casting cycle time. Therefore, an object of the present disclosure is to provide a spool bush having a new technical means capable of enhancing the cooling performance.

Means for Solving the Problems

[0006] The spool bush provided in the mold according to one aspect of the present disclosure includes an inner cylinder that forms a part of a flow path through which the molten molding material passes on the inner peripheral side, an outer cylinder that is a separate member from the inner cylinder and is immovable on one axial side that is the downstream side in the flow direction of the molten molding material and fits externally on the inner cylinder, and an annular flange that is a separate member from each of the inner cylinder and the outer cylinder and contacts the end portion on the other axial side of the outer cylinder from the other axial side. The inner cylinder has an attachment portion to which the flange is attached. A circumferential groove is provided along the circumferential direction on a first circumferential surface that is one of the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder. A coolant flow path is formed by the other second circumferential surface of the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder and the circumferential groove.

[0007] The spool bush according to another aspect of the present disclosure is provided in a mold. The spool bush includes an inner cylinder that forms a part of a flow path through which the molten molding material passes on the inner peripheral side, and an outer cylinder that is a separate member from the inner cylinder and fits externally on the inner cylinder. A common groove extending in the axial direction and a plurality of circumferential grooves each connected to the common groove and extending along the circumferential direction are provided on the mating surface of the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder. A partition block that divides the common groove into a first region on one circumferential side and a second region on the other circumferential side is provided in the common groove. The first region is connected to an inflow port of the coolant, and the second region is connected to an outflow port of the coolant.

Advantages of the Invention

[0008] According to the spool bush of the present disclosure, it is possible to enhance the cooling performance.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, with reference to the drawings, details of the embodiments of the present disclosure will be described. Note that at least a part of the embodiments described below may be arbitrarily combined.

[0011] FIG. 1 is a cross-sectional view of a casting mold 5 for which a spool bush 10 is used. The casting mold 5 is a mold for casting a metal such as aluminum, for example. The casting mold 5 includes a fixed mold 6, a movable mold 7, a subrunner 8, an intermediate sleeve 9, and a spool bush 10. Molten metal is supplied to the cavity Fb through a flow path F and a sprue runner Fa formed in the casting mold 5 by a molten metal supply machine 2 including a plunger 3 and a plunger sleeve 4. The inner peripheral sides of the intermediate sleeve 9 and the spool bush 10 form a part of the flow path F through which the molten metal passes. In addition, in the present embodiment, the molding die 5 is for casting as described above, and molten metal (molten metallic material) is used as the molten molding material. The molding die 5 may be for other purposes than casting. In this case, "molten metal" is read as "molten molding material". The sprue bush 10 is also called a pouring gate bush, a pouring gate sleeve, a runner bush, an injection sleeve, a mold sleeve, or a die sleeve.

[0012] FIG. 2 is a perspective view of the sprue bush 10 according to the first embodiment. FIG. 3 is an exploded perspective view of the sprue bush 10 shown in FIG. 2. FIG. 4 is a cross-sectional view of the sprue bush 10 shown in FIG. 2. The sprue bush 10 includes an inner cylinder 11, an outer cylinder 12, and an annular flange 13. The inner cylinder 11, the outer cylinder 12, and the flange 13 are made of steel. The inner cylinder 11 and the outer cylinder 12 are separate members. The flange 13 is a separate member from the inner cylinder 11 and a separate member from the outer cylinder 12.

[0013] Define the directions related to the sprue bush 10. The direction along the center line L of the cylindrical sprue bush 10 and the direction parallel to the center line L are defined as the "axial direction". The downstream side in the flow direction of the molten metal (the left side in FIGS. 1 to 3) is defined as the "one side in the axial direction", and the upstream side in the flow direction of the molten metal (the right side in FIGS. 1 to 3) is defined as the "other side in the axial direction". The direction perpendicular to the center line L is defined as the "radial direction". The direction along the circle centered on the center line L is defined as the "circumferential direction".

[0014] The inner cylinder 11 has a cylindrical shape. A part of the flow path F through which the molten metal passes is located on the inner peripheral side of the inner cylinder 11 (see FIG. 1). The flow path F is connected to the runner Fa on its downstream side. The runner Fa is constituted by the space between the inner cylinder 11 and the distributor 8 and the space formed in a part between the fixed mold 6 and the movable mold 7.

[0015] The inner cylinder 11 has a cylindrical inner body portion 16 and an annular flange portion 17 provided on one axial side of the inner body portion 16. The outer diameter of the inner body portion 16 is constant (except for the location where the circumferential groove 15 is formed), and it has a straight outer peripheral surface. The outer cylinder 12 is externally fitted onto the inner body portion 16. The flange portion 17 is provided to protrude radially outward from one axial end of the inner body portion 16 and contacts the end face 12e on one axial side of the outer cylinder 12. Due to the flange portion 17, the outer cylinder 12 is immovable in the axial direction and is externally fitted onto the inner cylinder 11.

[0016] The inner cylinder 11 has a mounting portion 14 to which the flange 13 is attached. The mounting portion 14 is constituted by a part (end portion) on the other axial side of the inner body portion 16. By attaching the flange 13, the mounting portion 14 prevents the outer cylinder 12 externally fitted onto the inner cylinder 11 from falling off to the other axial side. For this purpose, the mounting portion 14 has a mounting groove 24 formed on the outer peripheral side of the inner cylinder 11 and on the other axial side (see FIG. 4). A protrusion 48 of the flange 13 fits into the mounting groove 24. Further, as will be described later, the flange 13 is attached to the outer cylinder 12 by a set bolt 55. When the protrusion 48 contacts the mounting groove 24 in the axial direction, the outer cylinder 12 does not fall off to the other axial side.

[0017] The mounting groove 24 is an annular groove continuous along the circumferential direction. The mounting groove 24 has a first groove side surface 27 on one axial side, a second groove side surface 25 on the other axial side, and a groove bottom surface 26 connecting the first groove side surface 27 and the second groove side surface 25. The second groove side surface 25 has an inclined surface 25a that advances in one axial direction as it goes radially inward.

[0018] In this embodiment, a circumferential groove 15 for forming a coolant flow path 20 is formed on the outer peripheral surface 11a of the inner cylinder 11. The circumferential groove 15 is provided along the circumferential direction. A part of the coolant flow path 20 is formed by the space surrounded by the inner peripheral surface 12a of the outer cylinder 12 and the circumferential groove 15 of the inner cylinder 11. In the form shown in FIG. 4, two independent circumferential grooves 15 are formed, and two coolant flow paths 20 are constituted. The form of the coolant flow path 20 (circumferential groove 15) will be described later. The coolant flow path 20 is provided in the spool bush 10 and is a flow path through which coolant flows.

[0019] The outer cylinder 12 has a cylindrical shape. The outer cylinder 12 has a cylindrical outer main body portion 41 and a cylindrical extension portion 42. The extension portion 42 is provided to extend further in one axial direction from one axial end of the outer main body portion 41. The inner diameter of the outer main body portion 41 is the same as the inner diameter of the extension portion 42. A bolt hole 56 is formed at the other axial end of the outer cylinder 12. A fixing bolt 55 for the flange 13 is screwed into the bolt hole 56, and the flange 13 and the outer cylinder 12 are integrated.

[0020] The end face 12e on one axial side of the outer cylinder 12 (extension portion 42) contacts the flange portion 17 of the inner cylinder 11 over the entire circumference. Thereby, the outer cylinder 12 is immovable in one axial direction and is externally fitted to the inner cylinder 11. The space between the inner cylinder 11 and the outer cylinder 12 is sealed by O-rings 61, 62, 63. Note that a sealing material other than the O-ring 61 (62, 63) may be used, and a heat-resistant gasket or a sheet packing may be used. The outer cylinder 12 is provided with an inflow port P1 and an outflow port P2 (see FIG. 3) included in the coolant flow path 20. The outflow port P2 is provided adjacent to the inflow port P1 in the circumferential direction. Each of the inflow port P1 and the outflow port P2 is a hole penetrating the outer cylinder 12 in the radial direction and is connected to the circumferential groove 15.

[0021] In the forms shown in FIGS. 3 and 4, a first coolant flow path 20-1 on one axial side and a second coolant flow path 20-2 on the other axial side are provided. One inlet port P1 and one outlet port P2 are connected to the first coolant flow path 20-1, and another one inlet port P1 and another one outlet port P2 are connected to the second coolant flow path 20-2. A coolant supply device (not shown) is connected to each of the inlet port P1 and the outlet port P2.

[0022] As shown in FIG. 4, the flange 13 contacts the end face (end surface) 44 on the other axial side of the outer cylinder 12 from the other axial side. A plurality of through holes (counterbores) 49 are provided in the flange 13 along the circumferential direction. The flange 13 is fixed to the outer cylinder 12 by a set bolt 55. In the embodiment shown in FIG. 3, the flange 13 includes a plurality of arc-shaped split pieces 22, and these are provided along the circumferential direction to form an annular shape. That is, the flange 13 has a plurality of (two in the illustrated example) split pieces 22 that are split along the circumferential direction, and a plurality of tightening bolts 23 as fastening members for connecting these split pieces 22.

[0023] The tightening bolt 23 serves as a fastening member for tightening the split pieces 22 with a force having a radially inner component. For this purpose, a gap e is provided between the split pieces 22, 22, and when the tightening bolt 23 is tightened, the first split piece 22 is brought closer to a second split piece 22 that is separate from it.

[0024] Each divided piece 22 has, on its inner circumferential side, a protrusion 48 protruding radially inward. The surface on the other axial side of the protrusion 48 serves as a guide surface 28 (see FIG. 4). The guide surface 28 has an inclined surface that advances in one axial direction as it goes radially inward. The guide surface 28 contacts the inclined surface 25a of the mounting groove 24 provided in the inner cylinder 11. When the divided pieces 22, 22 are tightened by the tightening bolt 23, due to the wedging action of the guide surface 28 and the inclined surface 25a, the flange 13 is displaced in one axial direction with respect to the inner cylinder 11. As a result, the outer cylinder 12 is axially sandwiched between the flange 13 and the flange portion 17, and the outer cylinder 12 is in a state where an axial compressive force acts and is fixed to the inner cylinder 11.

[0025] The circumferential groove 15 for forming the coolant flow path 20 will be described. In the present embodiment, as described above, a first coolant flow path 20-1 on one axial side and a second coolant flow path 20-2 on the other axial side are provided. In order to form the first coolant flow path 20-1, the inner cylinder 11 is provided with a circumferential groove 15. As shown in FIG. 3, the circumferential groove 15 has a main groove portion 18 provided along the circumferential direction, and a detour groove portion 19 that is connected to the main groove portion 18 and detours axially from the main groove portion 18 to one axial side. The main groove portion 18 is a groove continuous in the circumferential direction and can be easily formed by machining using a lathe or the like. The detour groove portion 19 can also be easily formed by machining using a milling machine or a machining center or the like.

[0026] In the main groove portion 18, at the same position as the detour groove portion 19 in the circumferential direction, a plug member 21 that obstructs the flow of coolant in the main groove portion 18 is provided. The plug member 21 is a separate member from the inner cylinder 11 and is fixed to the inner cylinder 11 by bolts, welding, or the like. Although not shown, a partition block 33 that obstructs the flow of coolant in the main groove portion 18 is provided between a part in the main groove portion 18 (the part on the opposite side of the plug member 21) and between the inflow port P1 and the outflow port P2 for the first coolant flow path 20-1. Regarding the partition block 33, although the groove shape for forming the coolant flow path 20 is different, as shown in FIGS. 5 and 6, the partition block 33 is a member separate from the inner cylinder 11.

[0027] With the above configuration, when the coolant is supplied from the coolant supply device (not shown) to the inflow port P1, the coolant flows through the first half of the main groove portion 18 that constitutes the first coolant flow path 20-1, further flows through the detour groove portion 19, flows through the second half of the main groove portion 18, and is discharged from the outflow port P2.

[0028] As shown in FIG. 4, the detour groove portion 19 is formed on the outer peripheral surface on one axial side of the inner main body portion 16. Specifically, the detour groove portion 19 is formed on the outer peripheral surface of the inner main body portion 16 at the hem portion 17a of the flange portion 17. Thereby, it becomes possible to allow the coolant to reach one axial end of the spool bush 10.

[0029] In order to constitute the second coolant flow path 20-2, a circumferential groove 15 provided along the circumferential direction is provided in the inner cylinder 11. The circumferential groove 15 is a groove continuous in the circumferential direction and can be easily formed by machining using a lathe or a machining center or the like. A partition block 33 that obstructs the flow of the coolant in the circumferential groove 15 (similar to the case of the first coolant flow path 20-1) is provided between the inflow port P1 and the outflow port P2 for the second coolant flow path 20-2 in a part of the circumferential groove 15. With this configuration, when the coolant is supplied from the coolant supply device (not shown) to the inflow port P1, the coolant flows through the circumferential groove 15 that constitutes the second coolant flow path 20-2 and is discharged from the outflow port P2.

[0030] In the above embodiment, the circumferential groove 15 is formed on the outer peripheral surface 11a of the inner cylinder 11. If the outer cylinder 12 is externally fitted to the inner cylinder 11, a coolant flow path 20 is formed by the space formed between the circumferential groove 15 and the inner peripheral surface 12a of the outer cylinder 12. Although not shown, a circumferential groove may be formed on the inner peripheral surface 12a of the outer cylinder 12. In this case, if the outer cylinder 12 is externally fitted to the inner cylinder 11, a coolant flow path is formed by the space formed between the circumferential groove and the outer peripheral surface 11a of the inner cylinder 11.

[0031] Although not shown, a circumferential groove may be formed on the outer peripheral surface 11a of the inner cylinder 11 for the first coolant flow path 20-1, and a circumferential groove may be formed on the inner peripheral surface 12a of the outer cylinder 12 for the second coolant flow path 20-2. In this case, if the outer cylinder 12 is externally fitted to the inner cylinder 11, the first coolant flow path is formed by the space formed between the circumferential groove of the inner cylinder 11 and the inner peripheral surface 12a of the outer cylinder 12, and the second coolant flow path is formed by the space formed between the circumferential groove of the outer cylinder 12 and the outer peripheral surface 11a of the inner cylinder 11. Although not shown, a first circumferential groove may be formed on the outer peripheral surface 11a of the inner cylinder 11, and a second circumferential groove may be formed on the inner peripheral surface 12a of the outer cylinder 12 in accordance with the position of the first circumferential groove. In this case, if the outer cylinder 12 is externally fitted to the inner cylinder 11, one circumferential groove is formed by the first circumferential groove and the second circumferential groove. That is, if the outer cylinder 12 is externally fitted to the inner cylinder 11, the coolant flow path is formed by the space formed between the first circumferential groove of the inner cylinder 11 and the outer peripheral surface 11a of the inner cylinder 11 where the second circumferential groove is formed. That is, at least a circumferential groove 15 may be provided along the circumferential direction on the first circumferential surface which is one of the outer peripheral surface 11a of the inner cylinder 11 and the inner peripheral surface 12a of the outer cylinder 12. And a part of the coolant flow path 20 is constituted by the second circumferential surface which is the other of the outer peripheral surface 11a of the inner cylinder 11 and the inner peripheral surface 12a of the outer cylinder 12 and the circumferential groove 15.

[0032] A modified example of the circumferential groove for constituting the coolant flow path 20 will be described. FIG. 5 is a view of the inner cylinder 11 according to the modified example as seen from the radially outer side. FIG. 6 is a cross-sectional view of the inner cylinder 11 shown in FIG. 5 as seen from the axial direction. In FIGS. 5, 6 and FIG. 7 to be described later, the outer cylinder 12 and the flange 13 are shown by a two-dot chain line. Regarding the form shown in FIG. 5, the same components as those in the forms shown in FIGS. 2 and 3 are denoted by the same reference numerals, and the description thereof is omitted.

[0033] In FIGS. 5 and 6, a common groove 31 extending in the axial direction and a plurality of (six in the illustrated example) circumferential grooves 32 along the circumferential direction are provided on the outer peripheral surface 11a of the inner cylinder 11. Each of the plurality of circumferential grooves 32 is connected to the common groove 31. That is, the groove branches from the common groove 31 into the plurality of circumferential grooves 32. A partition block 33, which is a member different from the inner cylinder 11, is provided in the common groove 31. By the partition block 33, the common groove 31 is partitioned into a first region K1 on one side in the circumferential direction and a second region K2 on the other side. The partition block 33 is fixed to the inner cylinder 11 by bolts, welding, or the like. A part of the coolant flow path 20 is formed by the space formed between the common groove 31, the plurality of circumferential grooves 32, and the inner peripheral surface 12a of the outer cylinder 12.

[0034] The circumferential groove 32 is a groove continuous in the circumferential direction, similar to the main groove portion 18 shown in FIG. 3, and can be easily formed by machining using a lathe or a machining center. The common groove 31 can also be easily formed by machining using a milling machine or a machining center.

[0035] In the form shown in FIG. 5, the common groove 31 is axially divided into two by an annular partition wall 51, and the six circumferential grooves 32 are divided into a group of four circumferential grooves 32 and a group of two circumferential grooves 32. By the partition wall 51, each of the first region K1 and the second region K2 is also divided into one side and the other side in the axial direction. Thereby, a first coolant flow path 20-1 on one side in the axial direction and a second coolant flow path 20-2 on the other side in the axial direction are provided between the inner cylinder 11 and the outer cylinder 12.

[0036] In the first coolant flow path 20-1, the first region K1 is connected to one inflow port P1, and the second region K2 is connected to one outflow port P2. In the second coolant flow path 20, the first region K1 is connected to another inflow port P1, and the second region K2 is connected to another outflow port P2. Note that the partition wall 51 may be omitted, and a plurality of partition walls 51 may be provided according to the axial length of the spool bush 10. Accordingly, the number of the inflow port P1 and the outflow port P2 can also be freely changed.

[0037] Although not shown, a common groove and a plurality of circumferential grooves may be formed on the inner peripheral surface 12a of the outer cylinder 12. In this case, if the outer cylinder 12 is externally fitted to the inner cylinder 11, a coolant flow path is formed by the space formed between the common groove and the plurality of circumferential grooves and the outer peripheral surface 11a of the inner cylinder 11. That is, it is sufficient that a common groove 31 extending in the axial direction and a plurality of circumferential grooves 32 each connected to the common groove 31 and extending along the circumferential direction are provided on the mating surface of the outer peripheral surface 11a of the inner cylinder 11 and the inner peripheral surface 12a of the outer cylinder 12.

[0038] FIG. 7 is a cross-sectional view showing a part of the inner cylinder 11 shown in FIG. 5. As shown in FIGS. 5, 6, and 7, each of the coolant flow paths 20-1 and 20-2 has a partition member 35 in which a plurality of through holes 36 for passing coolant are formed. A plurality of types of through holes 36 having different coolant passage areas are formed in the partition member 35. In the first coolant flow path 20-1, small through holes 36S having a relatively small coolant passage area are provided in a portion close to the inflow port P1 (or the outflow port P2), and large through holes 36L formed of holes having a larger coolant passage area than the small through holes 36S are formed in a portion away from the inflow port P1 (or the outflow port P2).

[0039] This is because, in the first coolant flow path 20-1, the coolant flowing in from the inflow port P1 is evenly distributed to the plurality of circumferential grooves 32 as much as possible. As shown in FIG. 7, it is preferable that through holes 36 having a larger coolant passage area are formed farther from the inflow port P1 (or the outflow port P2). The partition member 35 is plate-shaped and, in the form shown in FIG. 5, is attached to the boundary portion between the common groove 31 and the circumferential groove 32. The partition member 35 is provided on the inflow port P1 side and is also provided on the outflow port P2 side. Note that the partition member 35 may be in a form other than that shown in the drawing and may be attached at other positions.

[0040] FIG. 8 is a diagram for explaining another modification of the circumferential groove 32 for forming the coolant flow path 20, and is a cross-sectional view of the inner cylinder 11. In the circumferential groove 32, a convex portion 52 protruding into the groove is formed. The convex portion 52 is provided along the circumferential direction. The convex portion 52 expands the contact area of the coolant like a so-called fin, and improves the cooling efficiency. Note that the configuration of the convex portion 52 may be applied to the form shown in FIG. 4. Regarding the form shown in FIG. 8 and the form shown in FIG. 9 to be described next, the same components as those in the forms shown in FIGS. 2 and 3 are denoted by the same reference numerals, and the description thereof is omitted.

[0041] FIG. 9 is a diagram for explaining still another modification of the circumferential groove for forming the coolant flow path 20, and is a cross-sectional view of the inner cylinder 11. The inner cylinder 11 has a cylindrical member 53 in which the circumferential groove 32 is formed as a separate member from the inner main body portion 16. The cylindrical member 53 is made of a material (for example, copper or aluminum) having a higher thermal conductivity than the inner main body portion 16. The cylindrical member 53 has a two-part structure and is attached along the outer peripheral surface of the inner main body portion 16. It is preferable that a grease having thermal conductivity is interposed between the inner main body portion 16 and the cylindrical member 53. The convex portion 52 shown in FIG. 8 may be applied to the circumferential groove 32 shown in FIG. 9. Further, the configuration of the cylindrical member 53 shown in FIG. 9 may be applied to the form shown in FIG. 4.

[0042] Regarding the spool bush 10 according to the embodiment As described above, the spool bush 10 according to each of the above embodiments is provided in a molding die 5 (see FIG. 1) for casting. The spool bush 10 (see, for example, FIG. 4) includes an inner cylinder 11 whose inner peripheral side forms a part of a flow path F through which the molten metal passes, an outer cylinder 12 which is a separate member from the inner cylinder 11 and is immovable in one axial direction and fits externally onto the inner cylinder 11, and an annular flange 13 which is a separate member from each of the inner cylinder 11 and the outer cylinder 12. The flange 13 contacts the end portion 44 on the other axial side of the outer cylinder 12 from the other axial side. The inner cylinder 11 has a mounting portion 14 to which the flange 13 is attached. A circumferential groove 15 is provided along the circumferential direction on a first circumferential surface which is one of the outer circumferential surface 11a of the inner cylinder 11 and the inner circumferential surface 12a of the outer cylinder 12. A coolant flow path 20 is formed by the second circumferential surface which is the other of the outer circumferential surface 11a of the inner cylinder 11 and the inner circumferential surface 12a of the outer cylinder 12, and the circumferential groove 15. In the embodiment shown in FIG. 4, the circumferential groove 15 is provided on the outer circumferential surface 11a of the inner cylinder 11, and the coolant flow path 20 is formed by the circumferential groove 15 and the inner circumferential surface 12a of the outer cylinder 12.

[0043] According to the spool bush 10, when the outer cylinder 12 is externally fitted onto the inner cylinder 11, a coolant flow path 20 is formed between them. If a circumferential groove 15 is formed on a first circumferential surface which is one of the outer circumferential surface 11a of the inner cylinder 11 and the inner circumferential surface 12a of the outer cylinder 12, since the coolant flow path 20 is formed, there is flexibility in the formation region of the circumferential groove 15, and it becomes possible to enhance the cooling performance of the spool bush 10. As shown in FIG. 4, by providing the circumferential groove 15 (detour groove portion 19) closer to one axial side of the inner cylinder 11, and as shown in FIG. 5, by providing a plurality of circumferential grooves 32 widely distributed in the axial direction, the cooling performance on one axial side of the spool bush 10, that is, the cooling performance at the rising portion of the sprue runner Fa, is enhanced. Further, when the outer cylinder 12 is externally fitted onto the inner cylinder 11 and the flange 13 is attached to the mounting portion 14 of the inner cylinder 11, the outer cylinder 12 externally fitted onto the inner cylinder 11 does not fall off to the other axial side, and the assembly of the spool bush 10 is easy.

[0044] In each of the above-described embodiments, in order to make the outer cylinder 12 externally fitted to the inner cylinder 11 immovable in one axial direction, the inner cylinder 11 has a cylindrical inner main body portion 16 and a flange portion 17. The flange portion 17 is provided to protrude radially on one axial side of the inner main body portion 16 and contacts the end face 12e on one axial side of the outer cylinder 12 (see FIG. 4). With this configuration, at one axial side of the spool bush 10, the edge 29 of the mating surface between the inner cylinder 11 and the outer cylinder 12 is not exposed in the flow path (pouring gate runner Fa) through which the molten metal passes. As a result, it is difficult for the molten metal passing through the pouring gate runner Fa to affect the space between the inner cylinder 11 and the outer cylinder 12. For example, an O-ring 61 is provided as a sealing material between the inner cylinder 11 and the outer cylinder 12 on one axial side, and it is difficult for the molten metal in the pouring gate runner Fa to thermally affect the O-ring 61.

[0045] In the case of the embodiment shown in FIG. 3, the circumferential groove 15 for the first coolant flow path 20-1 has a main groove portion 18 provided along the circumferential direction and a detour groove portion 19 connected to the main groove portion 18. The detour groove portion 19 is formed so as to detour axially from the main groove portion 18 to one axial side. In the main groove portion 18, at the same position in the circumferential direction as the detour groove portion 19, a plug member 21 that obstructs the flow of the coolant in the main groove portion 18 is provided. According to this configuration, by allowing the coolant to flow through the detour groove portion 19, it is possible to improve the cooling performance on one axial side of the spool bush 10. That is, the cooling performance at the rising portion of the pouring gate runner Fa is improved, the solidification of the molten metal in the pouring gate runner Fa is promoted, the casting cycle time is shortened, and the production efficiency is increased.

[0046] In the embodiment shown in FIG. 3, the flange 13 has split pieces 22, 22 that are divided into a plurality along the circumferential direction, and a fastening member (fastening bolt 23) for connecting these split pieces 22, 22 and tightening the split pieces 22, 22 radially inward. The mounting portion 14 of the inner cylinder 11 has a mounting groove 24 formed on the outer peripheral side of the inner cylinder 11 and on the other axial side (see FIG. 4). The groove side surface 25 on the other axial side of the mounting groove 24 has an inclined surface 25a that advances axially in one direction as it goes radially inward. Each of the split pieces 22, 22 has a guide surface 28 that contacts the inclined surface 25a.

[0047] With this configuration, when a plurality of split pieces 22, 22 are connected by a fastening member (fastening bolt 23) and the split pieces 22, 22 are fastened radially inward, the split pieces 22, 22 can fasten the outer cylinder 12 axially to one side by the guide surface 28 of the split piece 22 and the inclined surface 25a of the mounting groove 24 (by a wedge action). Further, the split pieces 22, 22 are attached to the outer cylinder 12 by set bolts 55. As a result, the integration of the inner cylinder 11, the outer cylinder 12, and the flange 13 is promoted.

[0048] The spool bush 10 according to the form (second form) shown in FIGS. 5, 6, and 7 is the spool bush 10 provided in the molding die 5, similar to the spool bush 10 shown in FIG. 2. Further, the spool bush 10 includes an inner cylinder 11 and an outer cylinder 12 which is a separate member from the inner cylinder 11 and fits over the inner cylinder 11. A part of the flow path through which the molten metal connected to the sprue runner Fa passes is located on the inner peripheral side of the inner cylinder 11. And in the second form, on the mating surface of the outer peripheral surface 11a of the inner cylinder 11 and the inner peripheral surface 12a of the outer cylinder 12, a common groove 31 extending in the axial direction and a plurality of circumferential grooves 32 each connected to the common groove 31 and extending along the circumferential direction are provided. The common groove 31 and the plurality of circumferential grooves 32 constitute a coolant flow path 20. A partition block 33 that divides the common groove 31 into a first region K1 on one side in the circumferential direction and a second region K2 on the other side is provided in the common groove 31. The first region K1 is connected to the coolant inlet port P1, and the second region K2 is connected to the coolant outlet port P2.

[0049] According to the spool bushing 10 according to the second embodiment, by fitting the outer cylinder 12 onto the inner cylinder 11, a coolant flow path 20 (20-1, 20-2) is formed between the inner cylinder 11 and the outer cylinder 12. The plurality of circumferential grooves 32 widely configure the coolant flow path 20 in the axial direction, making it possible to enhance the cooling performance of the spool bushing 10. In particular, by forming the circumferential groove 32 on one axial side, specifically on the outer peripheral surface of the inner main body portion 16 and at the hem portion 17a of the flange portion 17, it is possible to enhance the cooling performance on one axial side of the spool bushing 10. As a result, the cooling performance at the rising portion of the sprue runner Fa is improved, the solidification of the molten metal in the sprue runner Fa is promoted, the casting cycle time is shortened, and the production efficiency is increased. Also, it is only necessary to fit the outer cylinder 12 onto the inner cylinder 11, and the assembly of the spool bushing 10 is easy.

[0050] As shown in FIG. 7, the coolant flow path 20 has a partition member 35 in which a plurality of through holes 36 for allowing coolant to pass through are formed. As the plurality of through holes 36, there are small through holes 36S provided in a portion close to the inflow port P1 or the outflow port P2, and large through holes 36L formed by holes larger than the small through holes 36S and provided in a portion away from the inflow port P1 or the outflow port P2. With this configuration, it becomes possible to flow the coolant as evenly as possible in the plurality of circumferential grooves 32.

[0051] Also, as another example in which it is possible to flow the coolant evenly in the plurality of circumferential grooves 32, although not shown, as the plurality of circumferential grooves 32, there may be provided a small circumferential groove having a small cross-section for the passage of the coolant and a large circumferential groove having a cross-section for the passage of the coolant larger than that of the small circumferential groove. The small circumferential groove is provided in a portion close to the inflow port P1 or the outflow port P2, and the large circumferential groove is provided in a portion farther from the inflow port or the outflow port than the small circumferential groove.

[0052] Other modifications will be described. (A) of FIG. 10 is a cross-sectional view showing the exploded state of the spool bush 10, and (B) is a perspective view of the flange 13 of the spool bush 10. In the form shown in FIG. 10, the flange 13 is constituted by a single annular member. This point and the mounting configuration of the flange 13 are different from the form shown in FIG. 3. Other aspects are the same, and the description thereof will be omitted here.

[0053] In the form shown in FIG. 10, the mounting portion 14 of the inner cylinder 11 has an inner contact surface 66 that contacts the side surface (inner peripheral side surface) 65 on one axial side of the flange 13 and a first bolt hole 58. The first bolt hole 58 is a hole for fixing the flange 13 with the first stop bolt 57, and the first stop bolt 57 is tightened therein. The mounting portion 14 of the inner cylinder 11 is provided to protrude axially on the other side from the inner main body portion 16 and has a convex portion 67 for externally fitting the flange 13. The outer cylinder 12 has an outer contact surface 68 that contacts the side surface (outer peripheral side surface) 69 on one axial side of the flange 13 and a second bolt hole 60. The second bolt hole 60 is a hole for fixing the flange 13 with the second stop bolt 59, and the second stop bolt 59 is tightened therein.

[0054] A plurality of through holes (counterbore holes) 49a are provided along the circumferential direction in the flange 13 for passing the first stop bolt 57 therethrough. A plurality of through holes (counterbore holes) 49b are provided along the circumferential direction in the flange 13 for passing the second stop bolt 59 therethrough. By externally fitting the flange 13 onto the convex portion 67 and tightening the first stop bolt 57 and the second stop bolt 59, the flange 13 is fixed to the inner cylinder 11 and the outer cylinder 12, and the outer cylinder 12 is fixed in a state of being sandwiched between the flange 13 and the flange portion 17.

[0055] FIG. 11 shows yet another modified example. (A) of FIG. 11 is a cross-sectional view showing a disassembled state of the spool bush 10, and (B) is a perspective view of a flange 13 of the spool bush 10. In the form shown in FIG. 11, the flange 13 is constituted by a single annular member. In this regard, and regarding the mounting configuration of the flange 13, it is different from the form shown in FIG. 3. Other aspects are the same, and the description thereof is omitted here.

[0056] In the form shown in FIG. 11, a female screw 70 is formed on the inner peripheral surface of the flange 13. The mounting portion 14 of the inner cylinder 11 is provided so as to project axially to the other side from the inner main body portion 16, and has an annular convex portion 67 for externally fitting the flange 13. A male screw 71 that engages with the female screw 70 is formed on the outer peripheral surface of the annular convex portion 67. By tightening the flange 13 (female screw 70) to the convex portion 67 (male screw 71), the flange 13 is fixed to the inner cylinder 11, and the outer cylinder 12 is fixed in a state of being sandwiched between the flange 13 and the flange portion 17.

[0057] According to the mounting portion 14 (mounting structure of the flange 13) shown in each of FIGS. 10 and 11, similar to the form shown in FIG. 3, the inner cylinder 11, the outer cylinder 12, and the flange 13 are integrated. Moreover, if the outer cylinder 12 is externally fitted to the inner cylinder 11 and the flange 13 is attached to the mounting portion 14 of the inner cylinder 11, the outer cylinder 12 externally fitted to the inner cylinder 11 does not drop off to the other side in the axial direction, and the assembly of the spool bush 10 is easy.

[0058] 〔Other configurations〕 The above embodiments are illustrative in all respects and not restrictive. The scope of the rights of the present invention is shown not by the above embodiments but by the claims, and includes all modifications within the scope equivalent to the configurations described in the claims.

Description of reference numerals

[0059] 5 Mold 10 Spool bush 11 Inner cylinder 11a Outer peripheral surface 12 Outer cylinder 12e End face Inner circumferential surface of 12a 13 Flange 14 Mounting portion 15 Circumferential groove 16 Inner body portion 17 Flange portion 18 Main groove portion 19 Detour groove portion 20 Flow path for coolant 20-1 First flow path for coolant 20-2 Second flow path for coolant 21 Plug member 22 Split piece 23 Bolt (fastening member) 24 Mounting groove 25 Groove side surface 25a Inclined surface 28 Guide surface 31 Common groove 32 Circumferential groove 33 Partition block 35 Partition member 36 Through hole 36S Small through hole 36L Large through hole F Flow path K1 First region K2 Second region P1 Inflow port P2 Outflow port

Claims

1. A spool bush provided in a molding die, comprising: an inner cylinder that forms part of a flow path through which the molten molding material passes on the inner peripheral side; an outer cylinder that is a separate member from the inner cylinder and is immovable on one axial side that is the downstream side in the flow direction of the molten molding material, and is externally fitted to the inner cylinder; an annular flange that is a separate member from each of the inner cylinder and the outer cylinder and contacts the end on the other axial side of the outer cylinder from the other axial side; and comprising: the inner cylinder has a mounting portion to which the flange is attached; a circumferential groove is provided along the circumferential direction on a first circumferential surface that is one of the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder; a coolant flow path is formed by the second circumferential surface that is the other of the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder and the circumferential groove; the circumferential groove has a main groove portion provided along the circumferential direction, and a detour groove portion that is connected to the main groove portion and detours from the main groove portion to one axial side; a plug member that obstructs the flow of the coolant in the main groove portion is provided at the same position in the circumferential direction as the detour groove portion in the main groove portion; a spool bush.

2. A spool bush provided in a molding die, comprising: an inner cylinder that forms part of a flow path through which the molten molding material passes on the inner peripheral side; an outer cylinder that is a separate member from the inner cylinder and is immovable on one axial side that is the downstream side in the flow direction of the molten molding material, and is externally fitted to the inner cylinder; an annular flange that is a separate member from each of the inner cylinder and the outer cylinder and contacts the end on the other axial side of the outer cylinder from the other axial side; and comprising: the inner cylinder has a mounting portion to which the flange is attached; a circumferential groove is provided along the circumferential direction on a first circumferential surface that is one of the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder; a coolant flow path is formed by the second circumferential surface that is the other of the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder and the circumferential groove; the flange has a plurality of split pieces divided along the circumferential direction, and a fastening member for connecting the split pieces and tightening the split pieces radially inward; the mounting portion has a mounting groove formed on the outer peripheral side of the inner cylinder and on the other axial side; the groove side surface on the other axial side of the mounting groove has an inclined surface that advances in one axial direction as it goes radially inward; the split piece has a guide surface that contacts the inclined surface; a spool bush.

3. The inner cylinder according to claim 1 or claim 2, has a cylindrical inner main body portion and a flange portion that protrudes radially on one axial side of the inner main body portion and contacts an end surface on one axial side of the outer cylinder.

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