INJECTION DEVICE

Abstract

A flange is formed on a heating cylinder in a vicinity of a center in a longitudinal direction and a predetermined joining plate adheres to the flange. A flange plate is provided on a support frame. The joining plate is fixed to the flange plate to attach and detach freely, and the heating cylinder is caused to be supported by the support frame. Accordingly, movement in an axial direction and rotation of the heating cylinder are restricted. A guide portion for positioning during attachment and detachment is provided on one or both of the joining plate and the flange plate.

Claims

1. An injection device comprising: a heating cylinder; a screw provided to be drivable in an axial direction and a rotation direction inside the heating cylinder; and a support frame supporting the heating cylinder, wherein the heating cylinder is supported by the support frame in a state in which movement in the axial direction and rotation are restricted at a support position, the support position being a position close to a distal end portion by to of a length of the heating cylinder from a rear end portion of the heating cylinder.

2. The injection device according to claim 1, wherein a flange is formed on the heating cylinder at the support position, wherein the support frame includes a flange plate, and wherein the heating cylinder is supported by the support frame due to the flange being fixed to the flange plate.

3. The injection device according to claim 2, wherein a joining plate is fixed to the flange, wherein the flange is detachably fixed to the flange plate via the joining plate, and wherein a guide portion is formed on one or both of the joining plate and the flange plate, and the joining plate is positioned by the guide portion when being fixed to the flange plate.

4. The injection device according to claim 3, wherein the joining plate is detachably fixed to the flange plate via the guide portion.

5. The injection device according to claim 1, wherein the support frame is provided with an intermediate plate, wherein the intermediate plate comprises a support mechanism supporting the heating cylinder, and wherein the support mechanism is configured to loosely support the rear end portion of the heating cylinder.

6. The injection device according to claim 1, wherein the heating cylinder comprises: a front cylinder comprising a first flange portion having an expanded external diameter at a rear end portion of the front cylinder; and a rear cylinder comprising a second flange portion having an expanded external diameter formed on a distal end portion of the rear cylinder, wherein the external diameter of the first flange portion and the external diameter of the second flange portion are substantially the same, wherein the front cylinder and the rear cylinder are connected to each other in the longitudinal direction.

7. The injection device according to claim 1, wherein the heating cylinder comprises: a front cylinder comprising a step portion at a rear end portion of the front cylinder; and a rear cylinder comprising an annular protruding portion standing in a ring shape at a predetermined height from a distal end portion of the rear cylinder, and wherein when the rear end portion of the front cylinder and the distal end portion of the rear cylinder abut against each other, the annular protruding portion is inserted into and water-tightly connected to the step portion.

8. The injection device according to claim 1, wherein the support frame is configured to support the heating cylinder to restrict the movement of the heating cylinder toward the distal end portion at the support position.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0013] Illustrative embodiments of the present disclosure will be described in detail based on the following figures, wherein:

[0014] FIG. 1 is a perspective view illustrating an injection device according to an illustrative embodiment of the present disclosure;

[0015] FIGS. 2A and 2B are diagrams illustrating a portion of the injection device according to the illustrative embodiment of the present disclosure, in which FIG. 2A is a perspective view illustrating a portion of a heating cylinder and a portion of a support frame, and FIG. 2B is a front sectional diagram illustrating a portion of the heating cylinder and a portion of the support frame; and

[0016] FIG. 3 is a front sectional diagram illustrating an injection device of the related art.

DETAILED DESCRIPTION

[0017] Illustrative embodiments of the present disclosure will be described. Although the injection device according to the present disclosure may be provided for a general injection molding machine which injects a resin material, it is provided for a so-called metal injection molding machine which injects a metal material in the present illustrative embodiment. An injection device 1 according to the present illustrative embodiment is configured by a heating cylinder 2, a support frame 3 supporting the heating cylinder 2, and the like, as illustrated in FIG. 1. Although not illustrated in FIG. 1, a screw is provided inside the heating cylinder 2 and is driven in a rotation direction and an axial direction by a predetermined drive mechanism 5 which is provided on a rear end portion of the support frame 3.

[0018] Although the injection device 1 according to the present illustrative embodiment has several features, the injection device 1 primarily has features in the heating cylinder 2. In other words, the heating cylinder 2 is configured by two cylinder members, that is, a front-proximal front cylinder 7 and a rear-proximal rear cylinder 8 and the two are connected to each other in the longitudinal direction. A flange portion 10 having an expanded external diameter at the rear end portion is formed on the front cylinder 7 as illustrated in FIG. 2B. A step portion 11 of a predetermined width having an expanded diameter bore is formed at the rear end portion. A flange portion 13 similarly having an expanded external diameter is formed on the distal end portion of the rear cylinder 8 in the same manner as on the front cylinder 7. An annular protruding portion 14 which stands in a ring shape at a predetermined height only in the vicinity of the bore is formed on the end surface of the distal end of the rear cylinder 8. The step portion 11 and the annular protruding portion 14 form a spigot joint, and when the front cylinder 7 and the rear cylinder 8 abut against each other at the flange portions 10 and 13, respectively, the annular protruding portion 14 is smoothly inserted into and water-tightly connected to the step portion 11. Multiple bolt holes 18, 18, . . . are opened in the flange portions 10 and 13 of the front cylinder 7 and the rear cylinder 8 in a circumferential direction as illustrated in FIG. 2A, the flange portions 10 and 13 are fixed to a joining plate 16 described next by using bolts, thereby integrally fixing the front cylinder 7 and the rear cylinder 8 to each other. An injection nozzle 15 is provided on the front of the front cylinder 7 in the same manner as in the heating cylinder of the related art as illustrated in FIG. 1. Although the heating cylinder 2 is driven forward by the support frame 3 when the injection nozzle 15 is caused to touch the mold as described later, at this time, an axial force acts on the heating cylinder 2 via the flange portions 10 and 13.

[0019] The joining plate 16 is, as illustrated in FIG. 2A, formed from a rectangular plate having a predetermined plate thickness, a circular hole 17 being opened in the center of the joining plate 16, and the rear cylinder 8 is inserted into the hole 17. A circular step portion 19 that is shallowly carved out in a disc shape is formed in the periphery of the hole 17 in one surface of the joining plate 16. The diameter of the disc of the circular step portion 19 is just slightly larger than the flange portion 13 of the rear cylinder 8, and a portion of the flange portion 13 is smoothly fitted into the circular step portion 19 without a significant gap. Therefore, it is possible to precisely center the rear cylinder 8 and the joining plate 16. As illustrated in FIG. 2B, a circular step portion 20 that is shallowly carved out in a round shape is also formed in the periphery of the hole 17 in the other surface of the joining plate 16, and a predetermined portion of a flange plate 25 of the support frame 3 which is described later is fitted into the circular step portion 20 and centered, that is, positioned. Multiple bolt holes 21, 21, . . . are formed in the joining plate 16 along the circumferential direction in the circular step portion 19. As illustrated in FIG. 1, the front cylinder 7, the rear cylinder 8, and the joining plate 16 are integrally fixed to each other using bolts 23, 23, . . . . Bolt holes 24, 24, . . . are opened in the joining plate 16 in the vicinity of both short sides of the rectangle, and it is possible to fix the joining plate 16 to the flange plate 25 by using bolts.

[0020] The injection device 1 according to the present illustrative embodiment also has a feature in the support frame 3. In addition to an intermediate plate 27 supporting the heating cylinder 2 at the rear end portion of the heating cylinder 2 and a drive mechanism frame portion 28 provided with the drive mechanism 5 which drives the screw, the support frame 3 is provided with the flange plate 25 supporting the heating cylinder 2 in the vicinity of the center of the heating cylinder 2 in the longitudinal direction. The intermediate plate 27 and the drive mechanism frame portion 28, and the intermediate plate 27 and the flange plate 25 are coupled to each other in a fixed manner by using a plurality of rods between each. In the present illustrative embodiment, although a support mechanism 29 supporting the heating cylinder 2 is provided on the intermediate plate 27, by merely loosely supporting the rear end portion of the heating cylinder 2, the support mechanism 29 does not restrict movement in the rotation direction and the axial direction of the heating cylinder 2 at this portion. The support mechanism 29 is provided simply to center the rear end portion of the heating cylinder 2 and the intermediate plate 27.

[0021] The flange plate 25 is a characteristic member in the injection device 1 according to the present illustrative embodiment and is rectangular as illustrated in FIG. 2A. Since the heating cylinder 2 is pushed when causing the injection nozzle 15 to touch the mold, a load acts on the flange plate 25. A repulsive force also acts on the flange plate 25 during the injection. Therefore, the flange plate 25 is formed at a predetermined plate thickness. A comparatively large U-shaped opening portion 31 which reaches the center portion from the top end is formed in the flange plate 25, and the rear cylinder 8 of the heating cylinder 2 is configured to be inserted into the U-shaped opening portion 31. A step portion 32 which is shallowly carved out in a large rectangular shape is formed in the front surface of the flange plate 25 to leave a circular portion in the center portion of the front surface of the flange plate 25. When the joining plate 16 is inserted into the step portion 32, the end surfaces of both sides of the step portion 32 loosely touch the pair of side surfaces of the joining plate 16. A circular platform shaped protruding portion 33 which remains in the center of the step portion 32 is configured to fit into the circular step portion 20 which is formed in the joining plate 16. The step portion 32 and the protruding portion 33 of the flange plate 25 side and the pair of side surfaces of the joining plate 16 and the circular step portion 20 form guide portions for precisely positioning the joining plate 16 against the flange plate 25. Bolt holes 34, 34, . . . for fixing the joining plate 16 are opened in the step portion 32 of the flange plate 25.

[0022] A pair of piston cylinder units 35, 35 is provided on the support frame 3 provided with this flange plate 25 as illustrated in FIG. 1. The pistons of the piston cylinder units 35, 35 are connected to a fixing board which is not illustrated. Therefore, the support frame 3 is driven in the axial direction when the piston cylinder units 35, 35 are driven, and the heating cylinder 2 is driven forward such that the injection nozzle 15 touches the mold.

[0023] In the injection device 1, it is necessary to remove and attach the heating cylinder 2 and the screw with respect to the support frame 3 for appropriate maintenance. The method will be described First, the heating cylinder 2 is assembled. In other words, the front cylinder 7 and the rear cylinder 8 are caused to abut the flange portions 10 and 13, respectively, and the rear cylinder 8 is inserted into the hole 17 of the joining plate 16 to cause the joining plate 16 to abut against the flange portion 13 of the rear cylinder 8. Therefore, the front cylinder 7, the rear cylinder 8, and the joining plate 16 are precisely positioned, that is, centered. The front cylinder 7, the rear cylinder 8, and the joining plate 16 are fixed by using the bolts 23, 23 . . . . The heating cylinder 2 is assembled. In the present illustrative embodiment, the heating cylinder 2 which is assembled in this manner will not be disassembled as long as it is not necessary to do so, and in the attachment and detachment with respect to the support frame 3, the heating cylinder 2 is removed from and attached to the support frame 3 as it is in an assembled state.

[0024] The heating cylinder 2 is attached to the support frame 3. The screw is inserted into the heating cylinder 2 in advance, the body portion of the rear cylinder 8 of the heating cylinder 2 is inserted into the U-shaped opening portion 31 of the flange plate 25, and the rear end portion of the rear cylinder 8 is inserted into the support mechanism 29 of the intermediate plate 27. Therefore, the joining plate 16 abuts against the step portion 32 of the flange plate 25 and is precisely positioned, that is, centered. As illustrated in FIG. 1, the joining plate 16 is fixed to the flange plate 25 by using bolts 36, 36. Accordingly, movement of the heating cylinder 2 in an axial direction (e.g., in a direction toward the distal end) and rotation of the heating cylinder 2 can be restricted. The attachment of the support frame 3 of the heating cylinder 2 is completed. When removing the heating cylinder 2 from the support frame 3, the reverse work may be executed.

[0025] In the injection device 1 according to the present illustrative embodiment, the heating cylinder 2 is supported by the support frame 3 at the flange portions 10 and 13, and the movement in the axial direction and the rotation direction is restricted at the flange portions 10 and 13. Meanwhile, although the rear end portion of the heating cylinder 2 is supported by the support mechanism 29 of the intermediate plate 27, the movement in the axial direction and the rotation direction is not restricted. In other words, it can be said that the heating cylinder 2 is supported in a state in which the movement in the axial direction and the rotation direction is restricted in the vicinity of the center in the longitudinal direction. Therefore, when driving the piston cylinder units 35, 35 to cause the injection nozzle 15 to touch the mold, the axial force acting on the heating cylinder 2 only acts substantially on the front portion from the flange portions 10 and 13, that is, the front cylinder 7. Even if the axial force acts on the front cylinder 7, since the length of the front cylinder 7 is short, there is no concern of deformation caused by buckling. When the screw is rotated and the injection material is plasticized, although a torsion force caused by the rotation force acts on the heating cylinder 2, the shearing stress acting on the heating cylinder 2 itself only reaches a maximum in the vicinity of the flange portions 10 and 13, and the magnitude of the shearing stress is comparatively small. In other words, the heating cylinder 2 has great strength with respect to torsion in the injection device 1 according to the present illustrative embodiment. Although a broad explanation is given of the fact that the position of the flange portions 10 and 13 in the length direction of the heating cylinder 2, that is, the support position is in the vicinity of the center of the length of the heating cylinder 2, as long as the support position is a position approaching the distal end portion of the heating cylinder 2 from the rear end portion thereof by to of the length of the heating cylinder 2, the effects described above may be obtained.