JP2005279728A - Metal injection molding machine - Google Patents

Abstract

Provided is a metal injection molding machine in which a contact portion or the like between a cylinder barrel and a cylinder head does not protrude into an inner space of the cylinder barrel and the cylinder head.
A metal injection molding machine includes a cylinder barrel 11, a cylinder head 12 attached to the tip of the cylinder barrel 11, an injection nozzle attached to the tip of the cylinder head 12, a cylinder barrel 11 and a cylinder. And a screw 14 provided to rotate in the internal space of the head 12 and to be driven in the axial direction. The seal ring 16 held between the holding groove formed in the cylinder barrel 11 and the holding groove formed in the cylinder head 12 is radially outward of the cylinder barrel 11 and the cylinder head 12 from the peripheral surface of the internal space. Is located.
[Selection] Figure 1

Description

  The present invention relates to a metal injection molding machine for injection molding a molten material, and more particularly to a metal injection molding machine for injection molding a molten material such as an aluminum alloy or a magnesium alloy.

  FIG. 3 is a cross-sectional view showing a configuration near the tip of a cylinder barrel in a conventional metal injection molding machine. In addition, this kind of metal injection molding machine is conventionally well-known without mentioning a well-known technical literature.

  In FIG. 3, reference numeral 101 is a cylinder barrel, reference numeral 102 is a cylinder head attached to the tip of the cylinder barrel 101, reference numeral 103 is a mounting bolt for mounting the cylinder head 102 to the cylinder barrel 101, and reference numeral 104 is mainly a cylinder. A screw 105 provided to rotate in the barrel 101 and to be driven in the axial direction, reference numeral 105 indicates that the molten material flows backward in the axial direction of the screw 104 when the screw 104 is driven forward in the axial direction. The backflow prevention ring to prevent is shown. This type of injection molding machine, for example, an inline screw type injection molding machine, further includes a drive device (not shown) that rotates the screw 104 and drives it in the axial direction.

  In such an apparatus, the screw 104 is rotationally driven by a driving device, and a chip of a low-melting-point metal material such as magnesium alloy, aluminum alloy, zinc, or lead or a light alloy injection material is placed in the cylinder barrel 101 from a hopper (not shown). When these materials are supplied to, these materials are in a semi-molten or molten state due to frictional force generated by the rotation of the screw 104 or heat applied to the cylinder barrel 101 from the outside. At this time, the screw 104 moves backward in the axial direction, and the semi-molten or molten light alloy injection material is conveyed into the front space of the cylinder barrel 101 and a predetermined amount is accumulated. The light alloy injection material accumulated in the space is clamped from the injection nozzle portion (not shown) provided at the tip of the cylinder head by driving the screw 104 forward in the axial direction by a driving device. Injection into a mold cavity (not shown). Thereby, a light alloy molded product is obtained.

  Here, in the cylinder barrel 101 and the cylinder head 102 of the injection molding machine as described above, generally, a convex portion is formed on one of the connecting surfaces of the cylinder barrel 101 and the cylinder head 102, and a concave portion is formed on the other. In addition, it has a so-called inlay structure, and is configured such that the convex portion and the concave portion of each other are fitted. In the example shown in FIG. 4, a concave portion is formed in the cylinder barrel 101, and a convex portion that fits into the concave portion is formed in the cylinder head 102.

  Further, in the example shown in FIG. 3, seal surface protrusions 101 a and 102 a that protrude by about 1 mm are formed on the protrusions and the recesses formed on the cylinder barrel 101 and the cylinder head 102, respectively. The seal surface protrusions 101a and 102a are in mechanical contact with each other when the cylinder barrel 101 and the cylinder head 102 are fastened and fixed with the mounting bolts 103, and the seal surface protrusions 101a and 102a flow in the inner space of the cylinder barrel 101 and the cylinder head 102. The structure is such that molten or molten light metal injection material does not leak out between the cylinder barrel 101 and the cylinder head 102.

  However, as described above, the seal surface protrusions 101a and 102a formed on the cylinder barrel 101 and the cylinder head 102 have the seal surface protrusions 101a and 102a when the mounting bolt 103 is tightened at a specified tightening torque value or more. 102 a may be plastically deformed in the radial direction of the cylinder barrel 101 and the cylinder head 102.

  In particular, as shown in FIG. 3, when the seal surface protrusions 101a and 102a are in contact with the peripheral surfaces of the internal space of the cylinder barrel 101 and the cylinder head 102, the seal surface protrusions 101a and 102a are connected to the cylinder barrel 101 and the cylinder. When plastic deformation occurs inward in the radial direction of the head 102, they immediately protrude into the internal space of the cylinder barrel 101 and the cylinder head 102. Therefore, when the screw 104 is driven in the axial direction, a situation may occur in which the outer peripheral surface of the backflow prevention ring 105 contacts the seal surface protrusions 101a and 102a protruding into the internal space.

  In particular, when the seal surface protruding portion 101a protrudes into the internal space of the cylinder barrel 101, when the screw 104 is pulled out from the front end side of the cylinder barrel 101 when the injection molding machine is disassembled and repaired, a backflow prevention ring is provided. A screw flight 104 a spirally provided on the outer periphery of the screw 105 or the screw 104 is caught on the tip of the cylinder barrel 101, and the end surface of the cylinder barrel 101 is missing or cracked, or the screw 104 is pulled out from the cylinder barrel 101. In some cases, it is impossible to do so.

  Therefore, in order to confirm whether such a situation has occurred, the cylinder barrel 101 and the cylinder head 102 are disassembled, the vicinity of the seal surface protrusions 101a and 102a is inspected, and repairs are made as necessary. You have to do it regularly.

  The present invention has been made to solve the above-described problems of the prior art, and the contact portion between the cylinder barrel and the cylinder head does not protrude into the internal space of the cylinder barrel and the cylinder head. An object is to provide an injection molding machine.

  In order to achieve the above object, a metal injection molding machine according to the present invention includes a cylinder barrel, a cylinder head attached to the tip of the cylinder barrel, an injection nozzle attached to the tip of the cylinder head, An injection molding machine having a cylinder barrel and a screw provided to rotate in an internal space of the cylinder head and to be driven in an axial direction, wherein a contact means between the cylinder barrel and the cylinder head includes It is located in the radial direction outer side of the cylinder barrel and the cylinder head from the peripheral surface of the space.

  According to the metal injection molding machine of the present invention configured as described above, the contact means between the cylinder barrel and the cylinder head is located radially outside the peripheral surface of the internal space. Even if the barrel and cylinder head are excessively tightened by mounting bolts, or the hardness of the cylinder barrel decreases due to overheating, etc., the abutment means is plastically deformed even if it is plastically deformed in the radial direction. The means do not protrude into the interior space of the cylinder barrel and cylinder head.

  For this reason, when the screw is driven in the axial direction, the contact means protruding into the internal space of the cylinder barrel and the cylinder head comes into contact with the outer peripheral surface of the backflow prevention ring provided at the screw tip. Occurrence can be prevented. Also, when the screw is pulled out from the tip end of the cylinder barrel when the metal injection molding machine is disassembled and repaired, the plastically deformed contact means does not protrude toward the inner space at the tip of the cylinder barrel. Therefore, the screw flight spirally provided on the outer periphery of the backflow prevention ring or screw can be pulled out without being caught by the tip of the cylinder barrel, and the end face of the cylinder barrel may be missing or cracked, or the screw It is also possible to prevent a problem that the cylinder barrel cannot be pulled out.

  Further, the contact means may include a holding groove formed on each sealing surface of the cylinder barrel and the cylinder head and a seal ring held between the holding grooves.

  As described above, in the metal injection molding machine according to the present invention, the contact means between the cylinder barrel and the cylinder head is located radially outside the peripheral surface of the internal space. Even in the case of plastic deformation, the plastically abutting means does not protrude into the internal space of the cylinder barrel and cylinder head.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a configuration near the tip of a cylinder barrel in a metal injection molding machine according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing the configuration of the portion A shown in FIG. 1 (however, the cylinder barrel 11 and the cylinder head 12 are shown separated from each other).

  As in the conventional metal injection molding machine shown in FIG. 3, the metal injection molding machine of this embodiment shown in FIG. 1 includes a cylinder barrel 11, a cylinder head 12 attached to the tip of the cylinder barrel 11, and a cylinder head 12. A mounting bolt 13 for mounting on the cylinder barrel 11, a screw 14 provided to rotate in the internal space of the cylinder barrel 11 and the cylinder head 12 and driven in the axial direction, and the screw 14 forward in the axial direction It has a backflow prevention ring 15 that prevents the molten material from flowing backward in the axial direction of the screw 14 when driven. In addition, this type of metal injection molding machine, for example, an inline screw type metal injection molding machine, further includes a drive device (not shown) that rotates the screw 4 and drives it in the axial direction.

  Further, in the injection molding machine according to the present embodiment, holding grooves 11a and 12a for holding the seal ring 16 are provided in the convex portions and the concave portions formed on the sealing surfaces of the cylinder barrel 11 and the cylinder head 12, respectively. Is formed. These holding grooves 11 a and 12 a are separated from the peripheral surfaces of the internal space of the cylinder barrel 11 and the cylinder head 12. In other words, the holding grooves 11 a and 12 a are located on the radially outer side of the cylinder barrel 11 and the cylinder head 12 with respect to the peripheral surfaces of the internal spaces of the cylinder barrel 11 and the cylinder head 12. The holding grooves 11a and 12a and the seal ring 16 constitute contact means in the present invention.

  As shown in FIG. 2, when the cylinder barrel 11 and the cylinder head 12 are connected by the mounting bolt 13, the seal ring 16 is sandwiched between the holding grooves 11a and 12a. At this time, since the holding grooves 11a and 12a are separated from the peripheral surfaces of the internal space of the cylinder barrel 11 and the cylinder head 12 as described above, the seal ring 16 is naturally provided in the internal space of the cylinder barrel 11 and the cylinder head 12. It is away from the surrounding surface. Since the thickness of the seal ring 16 is larger than the sum of the depths of the two holding grooves 11a and 12a, when the cylinder barrel 11 and the cylinder head 12 are connected, a gap is generated by the difference between them. This means that the cylinder barrel 11 and the cylinder head 12 are in contact with each other only through the seal ring 16.

  According to the configuration of the present embodiment, the tightening torque by the mounting bolt 13 becomes excessive, or the hardness of the seal ring 16 decreases due to overheating or the like, so that the seal ring 16 has a radius of the cylinder barrel 11 and the cylinder head 12. In the case of some plastic deformation inward in the direction, the deformed portion is accommodated in a gap space formed between the seal ring 16 and the inner peripheral surface of the inner space of the cylinder barrel 11 and the cylinder head 12, and the cylinder It does not protrude into the internal space of the barrel 11 and the cylinder head 12.

  Therefore, when the screw 14 is driven in the axial direction, a situation occurs in which the seal ring 16 protruding into the inner space of the cylinder barrel 11 and the cylinder head 12 contacts the outer peripheral surface of the backflow prevention ring 5. This can be prevented. Even when the injection molding machine is disassembled and repaired, when the screw 14 is pulled out from the front end side of the cylinder barrel 11, a plastically deformed seal ring 16 remains at the front end portion of the cylinder barrel 11. Since the seal ring 16 does not protrude into the internal space of the cylinder barrel 11, the screw 14 can be pulled out without the backflow prevention ring 15 or the screw flight 14 a of the screw 14 being caught by the seal ring 16. It is possible to prevent the prevention ring 15 and the screw flight 14a from being scratched or damaged.

  In order to prevent the convex portion of the cylinder head 12 from being pushed by the seal ring 16 plastically deformed radially outward of the cylinder head 12 and being pushed out to the inner diameter side of the cylinder head 12, the holding grooves 11a and 12a are provided with As shown in FIGS. 2 and 3, it is preferable to be somewhat away from the sliding surface of the inlay structure formed by the concave portion of the cylinder barrel 11 and the convex portion of the cylinder head 12.

  The seal ring 16 is preferably made of a metal having heat resistance. This is to prevent the hardness of the seal ring 16 from being lowered due to overheating or the like and causing plastic deformation in the seal ring 16 more reliably. As the metal having heat resistance, for example, hot tool steel, nickel base alloy, cobalt base alloy, martensitic stainless steel, or the like can be used. Even if the seal ring 16 is plastically deformed or worn out, the seal ring 16 can be replaced, so that the repair is easy.

  Here, an example of the dimensions of each part of the present embodiment will be described. The inner diameter of the cylinder barrel 11 is 110 mm, and the seal ring 16 has an outer diameter of 166 mm, an inner diameter of 140 mm, and a thickness of 5 mm. Further, 15 M24 bolts were used as the mounting bolts 13 and their tightening torque was 390 N · m.

  Note that it is not a preferable event that a gap is formed between the seal ring 16 and the holding grooves 11a and 12a and the molten material enters the gap. Therefore, the seal ring 16 is attached to at least one of the holding grooves 11a and 12a by so-called shrink fitting or cold fitting so that no gap is generated between the seal ring 16 and the holding grooves 11a and 12a. preferable. Furthermore, it is preferable that a screw for a bolt for pushing out the seal ring 16 is formed on at least one of the cylinder barrel 11 and the cylinder head 12 so that the seal ring 16 can be easily removed during maintenance of the metal injection molding machine.

  In the present embodiment, the configuration in which one seal ring 16 is sandwiched between the two holding grooves 11a and 12a has been described. However, the configuration using the seal ring 16 is not limited to this configuration. It is also possible to attach the seal rings 16 to both of the 11 holding grooves 11a and the holding groove 12a of the cylinder head 12 so that the two seal rings 16 are in close contact with each other.

  In addition, although the structure in the sealing surface of the cylinder barrel 11 and the cylinder head 12 was demonstrated above, it is as above also about the structure in the sealing surface of the cylinder nozzle 12 and the injection nozzle part (not shown) attached to the front-end | tip. Similarly, a holding groove and a seal ring can be provided.

With tip of cylinder barrel in metal injection molding machine according to first embodiment of the present invention It is an expanded sectional view which expands and shows the structure of the A section shown in FIG. It is sectional drawing which shows the structure of the front-end | tip part vicinity of the cylinder barrel in the conventional metal injection molding machine.

Explanation of symbols

11 Cylinder barrels 11a, 12a Holding groove 12 Cylinder head 13 Mounting bolt 14 Screw 14a Screw flight 15 Backflow prevention ring 16 Seal ring

Claims (2)

A cylinder barrel (11), a cylinder head (12) attached to the tip of the cylinder barrel (11), an injection nozzle attached to the tip of the cylinder head (12), and the cylinder barrel (11 And a screw (14) provided to rotate in the internal space of the cylinder head (12) and to be driven in the axial direction,
The abutting means (11a, 12a, 16) between the cylinder barrel (11) and the cylinder head (12) has a radius of the cylinder barrel (11) and the cylinder head (12) rather than the peripheral surface of the internal space. A metal injection molding machine, which is located on the outside in the direction.   The contact means is held between the holding grooves (11a, 12a) formed on the seal surfaces of the cylinder barrel (11) and the cylinder head (12) and the holding grooves (11a, 12a). The metal injection molding machine according to claim 1, comprising a sealing ring (16) that is made.

Images