Base for injection molding machine

Abstract

A base for an injection molding machine has two side frames extending parallel with the axis of a drive actuator. Each of the side frames includes a lower flange supported by a bed, an upper flange disposed parallel with the lower flange, at least two webs connecting the upper flange and the lower flange, and a web reinforcing member fixed to the webs and penetrating through the webs. The side frames each have stiffeners connected between the lower and upper flanges and to one of the webs.

Claims

1. A base for an injection molding machine, the base for an injection molding machine comprising: two side frames extending parallel with an axis of a drive actuator; each of the two side frames comprising a lower flange supported by a bed, an upper flange disposed parallel with the lower flange, at least two webs connecting the upper flange and the lower flange, and a web reinforcing member fixed to the at least two webs while penetrating the at least two webs.

2. The base for an injection molding machine according to claim 1, wherein each side frame further comprises: a slide plate disposed on an upper surface of the upper flange and supporting a movable body moved by the drive actuator, the slide plate having a lateral center positioned offset from a lateral center of the upper flange toward a center of the injection molding machine, in a cross-sectional view of the side frame, and the at least two webs being positioned such that a center between two of the webs coincides with the lateral center of the slide plate; an anchor bolt hole positioned outside an outermost one of the at least two webs, in the lower flange; and a stiffener attached to the side frame and connected with an upper surface of the lower flange, an outer surface of the outermost web, and a lower surface of the upper flange.

3. An injection molding machine comprising: the base according to claim 2; and a mold clamping unit comprising: a fixed platen fixed to the base and supporting a fixed mold; a mold clamping cylinder movably disposed on the base; a mold opening/closing actuator indirectly moving the mold clamping cylinder; a movable platen disposed between the fixed platen and the mold clamping cylinder, supported by the base in a horizontally movable manner, and supporting a movable mold; and a tie bar extending horizontally from the fixed platen through the movable platen and the mold clamping cylinder, wherein the drive actuator is the mold opening/closing actuator, and the movable body is the movable platen.

4. The base for an injection molding machine according to claim 1, further comprising: a front cross member connecting front ends of the two side frames; and a rear cross member connecting rear ends of the two side frames.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Some preferred Examples of the present invention will be described in detail below with reference to the attached drawings.

(2) FIG. 1 is a perspective view of a base for an injection molding machine according to the present invention.

(3) FIG. 2 is a front view of a mold clamping unit.

(4) FIG. 3 is a cross-sectional view taken along the line 3-3 in FIG. 2.

(5) FIG. 4 is a cross-sectional view of a side frame.

(6) FIG. 5A is an explanatory diagram of action of a web reinforcing member of Comparative Example.

(7) FIG. 5B is an explanatory diagram of action of a web reinforcing member of Example.

(8) FIG. 6A is an explanatory diagram of action of a stiffener of Comparative Example.

(9) FIG. 6B is an explanatory diagram of action of a stiffener of Example.

(10) FIG. 7A is an explanatory diagram of processes from when webs are placed upright on a lower flange until when a web reinforcing member is inserted into the upright webs.

(11) FIG. 7B is an explanatory diagram of processes from when the web reinforcing member is joined to the webs until when an upper flange is placed on the webs.

(12) FIG. 7C is an explanatory diagram of processes until when a stiffener is positioned.

(13) FIG. 7D is an explanatory diagram of a process until when the stiffener is joined.

(14) FIG. 8A is an explanatory diagram of processes from when webs are placed upright on a lower flange until when a web reinforcing member is inserted into the upright webs.

(15) FIG. 8B is an explanatory diagram of processes until when the second web is attached.

(16) FIG. 8C is an explanatory diagram of processes until when the third web is attached.

(17) FIG. 8D is an explanatory diagram of a step of joining a stiffener.

(18) FIG. 9 is an exploded perspective view of a known base for an injection molding machine.

(19) FIG. 10 is a perspective view of a known base for an injection molding machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(20) Embodiments of the present invention will be described below with reference to the attached drawings.

(21) As illustrated in FIG. 1, a base 30 for an injection molding machine (hereinafter abbreviated as base) includes two right and left side frames 40,40 extending parallel with the axis of a mold opening/closing actuator (assigned with reference sign 16 in FIG. 2) being a drive actuator, a front cross member 31 connecting front ends of the two side frames 40,40, a rear cross member 32 connecting rear ends of the two side frames 40,40, bolts 33 fixing the front cross member 31 to the two right and left side frames 40,40, and bolts 34 fixing the rear cross member 32 to the two right and left side frames 40,40.

(22) Since the bolts 33, 34 are used for fixing, the two side frames 40,40, the front cross member 31, and the rear cross member 32 can be manufactured separately. The two side frames 40,40, the front cross member 31, and the rear cross member 32 manufactured separately are transported to an installation site. At the installation site, the two side frames 40 are aligned, the front cross member 31 is placed on the front ends of the two side frames 40,40, and the rear cross member 32 is placed on the rear ends of the two side frames 40,40. After the two side frames 40, the front cross member 31, and the rear cross member 32 are placed in predetermined positions, the bolts 33 and bolts 34 are screwed.

(23) The side frames 40 constitute a large portion of the base 30. When the side frames 40 have light weight, manufacturing cost and transportation cost of the base 30 can be reduced.

(24) A structure for achieving weight reduction of the side frames 40 will be described with reference to FIGS. 3 and 4. First, usage of the base 30 and the side frames 40 will be described with reference to FIG. 2.

(25) As illustrated in FIG. 2, a mold clamping unit 10 of the injection molding machine (hereinafter abbreviated as mold clamping unit) is a horizontal mold clamping unit including: the base 30 fixed to a bed 11 (or a substructure); a fixed platen 13 fixed to the base 30 and supporting a fixed mold 12; a mold clamping cylinder 15 movably disposed on the base 30; the mold opening/closing actuator 16 indirectly moving the mold clamping cylinder 15; a movable platen 18 being a movable body disposed between the fixed platen 13 and the mold clamping cylinder 15, supported by the base 30 in a horizontally movable manner, and supporting a movable mold 17; tie bars 19, 19 extending horizontally from the fixed platen 13 through the movable platen 18 and the mold clamping cylinder 15; a first coupling mechanism 20 coupling the mold clamping cylinder 15 with the tie bars 19, 19 when necessary; and a second coupling mechanism 22 mechanically coupling the mold clamping cylinder 15 with the movable platen 18.

(26) The mold clamping cylinder 15 includes a piston rod 14 disposed parallel with the fixed platen 13 and extending toward the fixed mold 12. The piston rod 14 is coupled with the movable platen 18.

(27) When the first coupling mechanism 20 is in an open state, the mold clamping cylinder 15 is released from the tie bars 19 and can be moved. When the first coupling mechanism 20 is in a closed state, the mold clamping cylinder 15 is coupled with the tie bars 19 and cannot be moved.

(28) The second coupling mechanism 22 can mechanically couple the movable platen 18 with the mold clamping cylinder 15 (locked state) and uncouple the movable platen 18 from the mold clamping cylinder 15 (unlocked state).

(29) In the locked state, the movable platen 18 and the mold clamping cylinder 15 are moved together, so that the mold opening/closing actuator 16 can move the movable platen 18 toward the fixed platen 13.

(30) After the movable mold 17 comes into contact with the fixed mold 12, the first coupling mechanism 20 is changed from the open state to the closed state. In the closed state, the mold clamping cylinder 15 is fixed to the tie bars 19.

(31) The second coupling mechanism 22 is changed into the unlocked state.

(32) The piston rod 14 moves forward to clamp the molds. Thereafter, injection is performed, the molds are open, and then the resultant product is taken out.

(33) Note that the mold clamping cylinder 15 may be substituted with a pressure receiving platen.

(34) The pressure receiving platen is fixed to the base 30. The tie bars 19 are disposed across the pressure receiving platen and the fixed platen 13. A toggle link and a hydraulic cylinder are disposed between the pressure receiving platen and the movable platen 18 and used for clamping the molds.

(35) As illustrated in FIG. 3, a foot member 23 called a shoe is disposed below the movable platen 18, and a slide plate 41 is disposed on the upper surface of the side frame 40. The foot member 23 moves in the front-rear direction of the drawing (the axial direction of the mold opening/closing actuator 16 in FIG. 2) while being in sliding contact with the slide plate 41.

(36) Preferably, side guides 42, 42 are disposed on the slide plate 41, sandwiching the foot member 23. The foot member 23 is guided by the side guides 42, 42 and thus does not move in the lateral direction of the drawing.

(37) Note that the slide plate 41 may be substituted with a rail, the foot member 23 may be substituted with a slider, and the slider may include steel balls. This structure is called a linear motion guide and reduces frictional resistance.

(38) As illustrated in FIG. 4, the side frame 40 includes a lower flange 44 supported by the bed 11 (or the substructure), an upper flange 45 disposed parallel with the lower flange 44, two webs 46,46 connecting the upper flange 45 and the lower flange 44, and web reinforcing members 47 fixed to the webs 46,46 while penetrating the webs 46,46.

(39) Square pipes are suitably used as the web reinforcing members 47; however, round pipes may be used.

(40) Action of the web reinforcing members 47 will be described with reference to FIGS. 5A and 5B.

(41) FIG. 5A illustrates Comparative Example that includes no web reinforcing member 47. When a load F1 is applied to the upper flange 45, the webs 46,46 deform as illustrated with the phantom lines. When the webs 46,46 are thickened to prevent the deformation, the side frame 40 becomes heavier.

(42) As illustrated in FIG. 5B, Example is provided with the web reinforcing member 47 connecting the webs 46,46. The web reinforcing member 47 can prevent deformation of the webs 46,46. Since the webs 46,46 are not required to be thickened, the side frame 40 remains lightweight.

(43) As illustrated in FIG. 4, the lateral center C1 of the slide plate 41 (or the rail) is preferably positioned offset from the lateral center C2 of the upper flange 45 toward the center of the mold clamping unit (injection molding machine) by an amount a, in a cross-sectional view of the side frame 40.

(44) The webs 46,46 are positioned in correspondence with the slide plate 41 (or the rail). In other words, each of the webs 46,46 is positioned such that the center of the group of the webs 46,46 (the center of the two webs) coincides with the lateral center C1 of the slide plate 41.

(45) The offset by the amount causes the lower flange 44 to extend outward. This extended portion is provided with anchor bolt holes 51. In other words, the anchor bolt holes 51 are positioned outside the outermost web 46 of the two webs 46,46, in the lower flange 44.

(46) The anchor bolt holes 51 disposed on the outer side enable attachment of anchor bolts 52 and fastening of nuts 53 from the outer side, and thus the side frame 40 is readily fixed to the bed 11 or the substructure.

(47) Note that the anchor bolts 52 are a generic name for bolts fixing the side frame 40 to the bed 11 (or the substructure) and may be general bolts.

(48) Preferably, a rectangular stiffener 55 is disposed in a region defined by the upper surface of the lower flange 44, the outer surface of the outermost web 46, and the lower surface of the upper flange 45. The lower side of the stiffener 55 is welded to the lower flange 44, a lateral side (the right side in the drawing) of the stiffener 55 is welded to the outermost web 46, and the upper side of the stiffener 55 is welded to the upper flange 45.

(49) The stiffener 55 is a plate-shaped reinforcing member that is disposed between the lower flange 44 and the upper flange 45 and that transmits a load applied to one of the lower flange 44 and the upper flange 45 to the other to prevent the lower flange 44 and the upper flange 45 from bending or deforming.

(50) Action of the stiffener 55 will be described in detail with reference to FIGS. 6A and 6B.

(51) FIG. 6A illustrates Comparative Example that includes no stiffener 55. When an upward force F2 is applied to the side, closer to the center of the mold clamping unit, of the lower flange 44 (a portion remote from the anchor bolt 52), the lower flange 44 slightly deforms from the anchor bolt 52 as illustrated with the phantom line. This deformation inclines the webs 46,46 as illustrated with the phantom lines.

(52) FIG. 6B illustrates Example that includes the stiffener 55 in addition to the web reinforcing member 47. This configuration prevents the lower flange 44 from deforming and the webs 46,46 from being inclined.

(53) Next, an example procedure for manufacturing the side frame 40 according to the present invention will be described with reference to FIGS. 7A to 7D.

(54) In the drawings, beads formed in welding are illustrated by solid triangles, and welded beads are illustrated by hollow triangles.

(55) As illustrated in FIG. 7A, the webs 46,46 are placed upright on the lower flange 44, and the webs 46,46 and the lower flange 44 are fixed to each other with beads B1. A welding rod 56 can be placed from the outer side, so that welding is readily performed. A coated welding rod is suitably used as the welding rod 56; however, a welding electrode may be used.

(56) The web reinforcing member 47 is then inserted horizontally into holes 46a,46a opening in the webs 46,46.

(57) As illustrated in FIG. 7B, both ends of the web reinforcing member 47 protrude from the webs 46,46. The welding rod 56 is placed from the outer side and welds the web reinforcing member 47 to the webs 46,46. The web reinforcing member 47 is fixed to the webs 46,46 with beads B2. The upper flange 45 is placed on the webs 46,46.

(58) As illustrated in FIG. 7C, the upper flange 45 is fixed to the webs 46,46 with beads B3. The welding rod 56 can be placed from the outer side, so that welding is readily performed. The rectangular stiffener 55 is then inserted so as to come into contact with the outermost web 46, the lower flange 44, and the upper flange 45.

(59) As illustrated in FIG. 7D, the stiffener 55 is fixed to the outermost web 46, the lower flange 44, and the upper flange 45 with beads B4. The welding rod 56 can be placed from the outer side, so that welding is readily performed.

(60) The manufacturing procedure described with reference to FIGS. 7A to 7D is merely an example and may be modified appropriately.

(61) Next, a manufacturing procedure in the case of three or more webs 46 will be described with reference to FIGS. 8A to 8D.

(62) In FIGS. 8A to 8D, three webs 46 are illustrated as a first web 46A, a second web 46B, and a third web 46C for the sake of convenience. The first web 46A is placed outermost, the third web 46C is placed innermost, and the second web 46B is placed therebetween.

(63) As illustrated in FIG. 8A, the first web 46A is fixed to the lower flange 44 with a bead B11, the upper flange 45 is fixed to the first web 46A with a bead B12, and the web reinforcing member 47 is fixed to the first web 46A with beads B13.

(64) Then, as illustrated in FIG. 8B, the second web 46B is positioned, fixed to the lower flange 44 with a bead B14, fixed to the upper flange 45 with a bead B15, and fixed to the web reinforcing member 47 with beads B16.

(65) Then, as illustrated in FIG. 8C, the third web 46C is positioned, fixed to the lower flange 44 with a bead B17, fixed to the upper flange 45 with a bead B18, and fixed to the web reinforcing member 47 with beads B19.

(66) As illustrated in FIG. 8D, the stiffener 55 is fixed to beads B20. The beads B11 to B20 can be readily welded by placing the welding rod from the outer side.

(67) This manufacturing procedure enables manufacture of a side frame with four or more webs 46 as well as three webs 46.

(68) The base 30 of the present invention is suitably used in a mold clamping unit of an injection molding machine but can also be applied to an injection unit of an injection molding machine, and is not limited to Example.

(69) An injection unit of an injection molding machine includes, as the main elements, a movable table disposed on the base 30 in a horizontally movable manner, a heating barrel disposed on the movable table and including a screw therein, and an injection unit moving actuator moving the movable table so that a nozzle at the tip of the heating barrel is fit to a sprue of a fixed mold 12 and that the nozzle is separated from the sprue.

(70) When the base is applied to the injection unit, the injection unit moving actuator corresponds to the drive actuator, and the movable table corresponds to the movable body.

(71) Note that the stiffener 55 is a rectangular flat plate in Example, but may be a C-beam or a H-beam extending longitudinally other than the flat plate.