JPH08117959A - Die clamping device in die casting machine - Google Patents

Abstract

PURPOSE: To obtain a die clamping device in a space-saving type die casting machine, in which closely contacting rigidity of both dies to the die clamping force is high and the development of burr is little. CONSTITUTION: In two pieces of platen direct pressing type die clamping devices, a shifting cylinder 60, tie bar nut attaching/detaching device 200, tie bar pulling- out device 300 providing a tie bar pulling-out cylinder 310, tie bar fixing device 100 for fixing a movable plate 3 to the tie bar 11 and die clamping cylinder 400 are provided. The tie bar fixing device 100 is composed of one pair of two half-nuts 110 for holding multi-groove parts 11X engraved on the outer periphery of the tie bar 11 and a holding means for half-nuts 110, and the die clamping cylinder 400 is arranged so as to be freely slid to a recessed space 400A carved on the side surface of the movable die 3 and the tip part is abutted on the end surface of the half-nuts 110 after holding and pressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device for a die casting machine, and in particular, it has high rigidity against a mold clamping force and
The present invention relates to a mold clamping device for a compact die casting machine that saves space.

[0002]

2. Description of the Related Art Generally, a mold clamping device for a die casting machine is
Similar to an injection molding machine, high-speed shock-free mold opening / closing operation and clamping force (clamping force) that is not defeated by resin pressure at the time of injection are required, and there are two major types: direct pressure type and toggle type. Be separated. Compared with the direct pressure type, the toggle type requires less oil when opening and closing the mold, and the direct pressure type requires the supply of high-pressure oil when holding the mold clamping force, whereas the toggle type has a self-locking function of the toggle mechanism. Since it works, it has various advantages such as energy saving compared to the direct pressure type. FIG. 8 is a vertical cross-sectional view showing a toggle type mold clamping device. The upper half of the center line shows a state before starting mold closing, and the lower half shows a mold closing completed state (toggle link extension completed state). . The mold clamping device 1000 in the figure includes a link housing 1, a fixed platen (fixed platen) 2, a movable platen (movable platen) 3, a mold 4 (a fixed mold 4b and a movable mold 4a), a bed 5, a toggle mechanism 6, It comprises a crosshead 7, a mold clamping cylinder (die lock cylinder) 8, a piston rod 9 and a guide rod 10. In the double toggle type mold clamping device 1000 of the injection molding machine, as shown in the drawing, a pair of upper and lower toggle mechanisms 6 including three toggle links 6a, 6b, 6c are provided between the movable platen 3 and the link housing 1. A mold clamping cylinder (die lock cylinder) 8 is attached to a substantially central portion of the outer end surface of the link housing 1, a tip of a piston rod 9 of the mold clamping cylinder 8 is connected to a crosshead 7, and the crosshead 7 can be moved back and forth. While moving forward and backward along the inserted guide rod 10,
The toggle mechanism 6 is operated via the crosshead 7 to move the movable platen (movable platen) 3 with respect to the fixed platen (fixed platen) 2 to perform the mold clamping operation. Specifically, as shown in FIG. 9, the mold 4 is tightened by advancing the mold clamping cylinder 8 from the mold open state in which the toggle links 6a, 6b, 6c of the toggle mechanism 6 are folded. The amount of oil sent to the mold clamping cylinder 8 is adjusted to obtain a high-speed and smooth mold clamping operation. Immediately before the touch of the mold 4 in FIG. 10, if there is a product left between the molds 4a and 4b or if there is a foreign substance, the mold 4 may be damaged. Set low and low oil and oil pressures and tighten. From the touched state of the mold of FIG. 10, in order to generate a mold clamping force to firmly clamp the two molds 4a and 4b, high-speed and high-pressure oil is sent to the mold clamping cylinder 8 and the toggle mechanism 6 moves. Set the toggle links 6a and 6b in the extended state,
A mold clamping force is generated in the mold by extending the length Lt of the tie bar 11 between the link housing 1 and the fixed platen 2. The state where the tie bar 11 is extended and the mold clamping is completed is as shown in FIG. 11, and at this time, the toggle links 6a and 6b are completely extended and are in a straight line state, and high pressure oil is supplied to the mold clamping cylinder 8 to form a self-locking state. Since this state is maintained even if it is not sent, it is superior in energy saving compared to the direct pressure type. The mold clamping force is adjusted by changing the extension amount of the tie bar 11 from the state of touching the mold shown in FIG. When increasing the mold clamping force, the link housing 1 is further advanced toward the fixed platen 2, and when decreasing it, it is retracted. This link housing 1 is moved by a die height motor (not shown).
This is performed by driving a chain wound around four tie bar nuts fastened to the book tie bar 11. The amount of movement is controlled by the amount of rotation of the die height motor.

On the other hand, as shown in FIG. 12, the direct pressure type mold clamping device is guided by tie bars 11 penetrating the four corners of the movable platen 3 so that the movable platen 3 can be moved forward and backward by driving a mold clamping cylinder 8. ing.

By the way, in the world of die casting machines,
Since high-speed and high-pressure filling is performed compared to an injection molding machine, the high-speed molten metal moved by the hydraulic cylinder reaches the mold cavity and is restrained from moving, resulting in the mold opening force generated by the peak pressure generated. The mold being clamped tends to open, and so-called burrs often occur, in which the molten metal is ejected from the boundary surface of the slightly opened mold. Therefore, the mechanical lock type mold clamping device (that is, the toggle type mold clamping device), which has been considered to have high rigidity against the mold clamping force, has been used more than the direct pressure type mold clamping device. That is, the toggle type mold clamping device tries to counteract the force to open the mold at the time of strong mold clamping pressure with the extension force of the tie bar,
In the conventional direct pressure type mold clamping device having three platens shown in FIGS. 8 to 9, the hydraulic oil in the mold clamping cylinder is set against the mold opening force due to the peak pressure of the high-speed and high-pressure molten metal at the time of filling described above. As a result of being compressed and increased in pressure, a high hydraulic oil pressure is used to oppose. Therefore, when countering the mold opening force at the time of filling, the compressibility of the hydraulic oil is much larger than the elastic deformation ratio of the metal (tie bar). As a result, the conventional type (three-platen system) direct pressure type mold clamping is performed. It was considered that the toggle type mold clamping device had a larger mold clamping holding force than the device and less burr was generated by that amount, so that it was suitable for a die casting machine.

[0005]

However, the toggle type mold clamping device is one type of three platen system having a fixed platen, a movable platen, and a link housing, and
Since the crossheads and toggle links that make up the toggle mechanism are interposed between the platens, the length of the machine becomes long, and it occupies a large installation area on the factory premises, which is a problem from the viewpoint of space saving. Therefore, it can be installed in a small installation area equivalent to or less than the toggle type mold clamping device, and the mold clamping holding force (to close the mold against the mold opening force due to the inertial force of the molten metal) possessed by the toggle type mold clamping device. Resistance to leave)
There has been a long-awaited expectation for a mold clamping device suitable for a die casting machine having a larger mold clamping holding force.

[0006]

In order to solve the above-mentioned problems, the present invention comprises a movable platen and a fixed platen through which tie bars are inserted, and the movable platen is arranged so that it can be contacted and separated from the fixed platen. In a mold clamping device of a direct pressure type die casting machine for moving the movable plate and clamping the mold, the mold clamping device includes a moving cylinder for moving the movable plate forward and backward, and attachment and detachment of a tie bar nut screwed to the tie bar. A device, a tie bar removing device having a tie bar removing cylinder, and a tie bar fixing device for fixing the movable plate after the mold closing operation to the tie bar,
A mold clamping cylinder for pressing the movable plate after the mold is closed against the fixed plate, and the tie bar fixing device includes a pair of half nuts and a pair of half nuts for holding multiple groove portions engraved on the outer periphery of the tie bar. A piston which comprises a nut gripping means, the mold clamping cylinder is slidably disposed in a recessed space bored in the side surface of the movable plate, and the tip of which comes into contact with and presses the end surface of the half nut after gripping. It was configured with.
In the second invention, the tie bar nut attaching / detaching device is 2
Open / closeable tie bar nuts, each of which is divided into a semi-circular shape, and one end of which is pivotally attached to the fixed plate side and which is screwed with the threaded portion of the tie bar, and a four-joint link which is pin-joined to each free end of the tie bar nut. And a means for opening and closing the tie bar nut, which is composed of a link mechanism consisting of and a hydraulic cylinder connected to the four-bar link.

[0007]

In the present invention, the movable plate feeds hydraulic oil to the moving cylinder and moves from the mold open state to the mold closed state. When the movable die attached to the movable plate comes into light contact with the fixed die attached to the fixed plate, the movement of the movable plate is stopped, and two pairs of half nuts of the tie bar fixing device are meshed with the multiple groove portions of the tie bar, The movable plate and tie bar are solidified and integrated. After that, pressure oil is sent to the mold clamping cylinder to strongly press both molds through the extension force of the tie bar. After the above mold clamping process is completed, the injection mold is used to fill the mold cavity with molten metal, and after cooling and solidification, to open the mold, release the hydraulic oil in the mold clamping cylinder and then release the half nut. Then, the movable platen is retracted by the moving cylinder. When replacing the mold, it is almost always necessary to remove the tie bar.In this case, first untie the tie bar nut and tie bar with the tie bar nut attaching / detaching device, and then remove the tie bar in the axial direction with the tie bar removing device. Move to and separate from the mold attachment part. The mold clamping device of the present invention is a two-platen direct pressure type mold clamping device, which is space-saving and compact as compared with the conventional type (toggle type or three-platen platen direct pressure type), and as described later, Has high rigidity against tightening force and little burr is generated. Further, in the second invention, since the tie bar nut is attached and detached via the link mechanism, the tie bar nut can be attached and detached easily and easily, and a strong screw can be formed.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 7 relate to an embodiment of the present invention,
1 is an overall plan view of the mold clamping device, FIG. 2 is an enlarged plan view of a main part of the tie bar fixing device of the mold clamping device, FIG. 3 is a front view taken along line AA of FIG. 2, and FIG. 4 is a front view of the tie bar fixing device. FIG. 5 is a side view of the tie bar nut attaching / detaching device of the mold clamping device, FIG. 6 is a front view taken along the line BB of FIG. 5, and FIG. 7 is a front view of the tie bar nut attaching / detaching device. As shown in FIG. 1, the die-clamping device 1000 of the die-casting machine according to the present invention includes tie bars 11 each other.
A fixed platen 2 which is inserted into the four corners and a movable platen 3 which can freely come into contact with and separate from the fixed platen 2 are arranged on a machine base (not shown),
The fixed plate 2 has a fixed mold 4b, and the movable plate 3 has a movable mold 4a.
Of the tie bar nut attaching / detaching device 200 for detachably attaching the tie bar nut 210 and the moving cylinder 60 as the advancing / retreating means of the movable platen 3.
, Tie bar removing device 300, and tie bar fixing device 10
0, and a mold clamping cylinder 400 and the like. The moving cylinders 60 are fixed to the left and right ends of the fixed platen 2, respectively, and the tips of the piston rods 60a are connected to the ends of the movable platen 3 to move the movable platen 3 back and forth in the axial direction.

Next, the tie bar fixing device 100 will be described with reference to FIGS. Tie bar fixing device 100
Has a function of fixing the movable platen 3 to the tie bar 11 after bringing the movable platen 4a of the movable platen 3 into contact with the fixed mold 4b, and engraved on the outer periphery of each of the four tie bars 11. The pair of left and right half nuts 110, 110 for gripping the formed multiple groove portion 11X are moved forward and backward in the direction perpendicular to the axis by the half nut opening / closing cylinder 120 attached to the side opposite to the fixed platen of the movable platen 3, as shown in FIGS. As shown, a pair of left and right half nuts 110, 110 having multiple groove portions 110X fitted to the multiple groove portions 11X on the inner surface are slidably fitted inside a tubular nut box 123 having a rectangular cross section. The upper and lower two guide rods 122, 122 penetrating the respective half nuts 110, 110 are locked to the end plate 121 on which the half nut opening / closing cylinder 120 is fixed, and Two half nuts 110, 110 by mounting the corner annular stopper 124 and 125 to left and right ends of the boxes 123 Nut box 1
It slides and opens and closes within the range of 23. That is, by sending hydraulic oil from the open state of FIG. 3 to the head side 120H of the half nut opening / closing cylinder 120,
The piston 120a and the piston rod 120b move forward, move forward until the right half nut 110 contacts the tie bar 11, and when the piston rod 120b further moves forward, the right half nut 110 is stopped by the tie bar 11, so that the end plate 121. Retreat, guide rod 12
The left half nut 110 is attached to the tie bar 1 by the end of 2.
1 until it comes into contact with the tie bar 11, and the tie bar 11 and the half nuts 110, 110 are engaged and integrated with each other. Half nut moving cylinder 1 shown in FIG.
30 is the multiple groove portion 11X of the tie bar 11 and the half nut 1
It is used for fine adjustment to match the 10 multi-groove portions 110X. That is, as shown in FIGS. 2 to 4, a guide block 126 is stretched outside the nut box 123, and the two through holes formed in the guide block 126 are joined to the movable platen 3 at their tips. The guide bar 127 penetrates, the guide block 126 is slidably movable in the axial direction of the guide bar 127, and the half nut moving cylinder 130 is operated to operate the half nut 110 and the tie bar 1.
The multiple groove parts of 1 are finely adjusted to the position where they mesh properly,
After the adjustment, the set bolt 128 screwed to the other end plate of the guide bar 127 is positioned and fixed. Although the guide block 126 and the guide bar 127 are attached to the side surface of the half nut device in FIG. 2, they may be provided on the upper part of the half nut device as shown in FIGS. 3 to 4. It can also be provided at the bottom.

Next, the mold clamping cylinder 400 will be described. As shown in FIG. 2, the mold clamping cylinder 4 according to the present invention.
00 is a side surface of the movable platen 3 in the direction opposite to the fixed platen, and is a substantially cylindrical recess space 400A at a position where the tie bars 11 penetrate.
And a cylindrical bush 410 having a stepped cylindrical shape to be fitted around the tie bar 11 and a bushing 420 having a cylindrical shape fitted to the outer circumference of the stepped portion of the piston 410. Is slightly slidable in the axial direction, and pressure oil is supplied to the space 400B on the right side of the piston 410 in FIG.
That is, in the mold clamping cylinder 400, the cylinder is a movable platen 3.
Is the recess space 400A formed in the
Is a kind of hydraulic cylinder having a short stroke length that moves axially inside thereof, and the side surface of the half nut 110 after engaging with the tie bar 11 in the tie bar fixing device 100 (corresponding to FIG. 4) is moved to the left side. Both dies 4a, 4b are pushed by the extension force of the tie bar 11 by being pressed.
It is one that strongly presses. Therefore, the nut box 1
A through hole 123A having a larger diameter than the outer diameter of the piston 410 is provided in a space through which the tie bar 11 penetrates on the side surface of 23.
Since the piston 410 of the mold clamping cylinder 400 is required to have a large pressing force, the bore diameter (outer diameter) A is large and the stroke S is designed to be small.

Next, the tie bar nut attaching / detaching device 200 will be described. As shown in FIG. 5 to FIG. 7, among the four tie bars 11, the two tie bars located at the top are temporarily provided so that the tie bars 11 and 11 do not get in the way when the molds 4a and 4b are replaced. It is necessary to pull out the tie bars 11 and 11, so that the tie bar nut 210 attached to the side opposite to the movable platen of the fixed platen 2 can be easily attached and detached easily and easily and automatically.
Tie bar nut attachment / detachment device 2 for attaching / detaching 10 screws
00 is provided. That is, the fixed plate 220 attached to the outer end surface of the fixed platen 2, the vertical plate 222 parallel to the fixed plate 220, the horizontal plate 230 connecting the two, the connecting plates 231 and 4
In the space formed by the stays 232 of the book, the pin 210a
A pair of upper and lower tie bar nuts that can be opened and closed by closing the
210 to the first link 252 (links 252a, 252
b, 252c) and the second link 254, the horizontal cylinder 230 is opened and closed by the operation of the hydraulic cylinder 240 pivotally supported by the horizontal plate 230 via the bracket 242. Nut 21
0 Screw the threaded portion on the inner surface. The link mechanism 250 constitutes a four-bar link having four pins 210a, 210b, 210c, 210d, and hydraulic pressure is applied via a pin 210e fitted in an elongated hole 244A of a metal fitting 244 attached to the tip of the piston rod 240a. It is connected to the cylinder 240. When the piston rod 240a of the hydraulic cylinder 240 moves forward, the tie bar nut 210 is fixed to the tie bar 11 by moving from the open state of FIG. 6 to the closed state (screwed state) of FIG.

The operation of the mold clamping apparatus 1000 of the present invention constructed as above will be described below.
The following procedure is used to change the mold 4b from the mold open state to the mold closed state. (1) The movable cylinder 60 is moved backward to move the movable platen 3 toward the fixed platen 2. (2) The movable mold 4a of the movable platen 3 is the fixed mold 4 of the fixed platen 2.
After contacting b, the movable platen 3 is stopped and the half nut 11
0 is tightened by the half nut opening / closing cylinder 120, and the tie bar 11 and the half nut 110 are fixed and integrated. (3) The piston 410 of the mold clamping cylinder 400 is moved forward (on the side opposite to the fixed platen) to press the side surface of the half nut 110. Further, in order to change the mold closed state to the mold opened state, (1) the pressure oil for advancing to the piston 410 of the mold clamping cylinder 400 is released. (2) The half nut opening / closing cylinder 120 is operated to release the coupling between the tie bar 11 and the half nut 110. (3) The movable cylinder 60 is moved forward to move the movable platen 3 in the direction opposite to the fixed platen. Further, when the tie bar 11 is temporarily removed, such as when changing the mold, (1) the mold is opened in advance. (2) The tie bar nut attaching / detaching device 200 is operated to release the screwed state of the tie bar nut 210. (3) The tie bar removing cylinder 310 is operated to move forward to move the tie bar 11 toward the movable plate.

Next, regarding the contact rigidity of the mold at the time of mold clamping, a conventional example (toggle type and three-platen direct pressure type) and the present invention will be compared on the basis of an actual machine. According to Hooke's law, the spring constant K ₁ of the tie bar 11 is obtained by F = Kx (x is displacement), so that the spring constant K ₁ = (AE) / L ₁ (where A is the tie bar breakage). Area, E is Young's modulus, L ₁ is tie bar length). This represents the contact rigidity in the toggle type mold clamping device. On the other hand, in the direct pressure type mold clamping device, the spring constant K ₁ which is the extension rigidity of the tie bar calculated similarly to the toggle type and the spring constant K ₂ which is obtained as the compression rigidity of the hydraulic oil in the mold clamping cylinder are dynamically calculated. The composite spring constant K _t obtained as a composite is

[0014]

1 / K _t = 1 / K ₁ + 1 / K ₂

It is obtained by When the working oil having the capacity V (cross-sectional area A × stroke S) in the mold clamping cylinder is the working oil pressure P and the compression rate is β, the displacement amount ΔL = ΔV / A = P
Since SAβ / A, the spring constant K ₂ is

[0016]

[Equation 2]

Therefore, the combined spring constant K _t is also the spring constant K ₁
And the spring constant K ₂ . Using the above arithmetic expressions, the toggle type (conventional), the three-platen direct pressure type (conventional), and the two-platen direct pressure type mold clamping device of the present invention can be used in two cases, large (2500 TON) and small (850 TON). Table 1 shows a summary of the calculation of the above.

[0018]

[Table 1]

From Table 1, it is understood that the toggle type has a much larger spring constant and a higher contact rigidity than the three-platen direct pressure type, but the spring constant of the two-platen direct pressure type mold clamping device of the present invention. It can be seen that K _t is extremely large as compared with the conventional example.

[0020]

As described above, the die-clamping machine of the die-casting machine of the present invention has a larger adhesion rigidity at high speed filling than the conventional one, and an excellent molded product free from burrs can be obtained, and space saving can be achieved. In addition, driving operability and maintainability are improved.

[Brief description of drawings]

FIG. 1 is an overall plan view of a mold clamping device according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view of an essential part of the tie bar fixing device of the mold clamping device according to the embodiment of the present invention.

FIG. 3 is a front view taken along the line AA of FIG.

FIG. 4 is a front view of the tie bar fixing device of the mold clamping device according to the embodiment of the present invention.

FIG. 5 is a side view of the tie bar nut attaching / detaching device of the mold clamping device according to the embodiment of the present invention.

6 is a front view taken along the line BB of FIG.

FIG. 7 is a front view of the tie bar nut attaching / detaching device of the mold clamping device according to the embodiment of the present invention.

FIG. 8 is a side sectional view of a conventional toggle type mold clamping device.

FIG. 9 is a plan view of a conventional toggle type mold clamping device.

FIG. 10 is an explanatory view (plan view) of a conventional toggle type mold clamping device.
Is.

FIG. 11 is an explanatory view (plan view) of a conventional toggle type mold clamping device.
Is.

FIG. 12 is a schematic perspective view of a conventional direct pressure type mold clamping device.

[Explanation of symbols]

 1 link housing 2 fixed plate 2a tie bolt fixed plate 2A fixed plate 2N nut 3 movable plate 4 mold 4a movable mold 4b fixed mold 5 bed 6 toggle mechanism 6a toggle link 6b toggle link 6c toggle link 7 crosshead 7a fixed nut 8 Mold clamping cylinder 9 Piston rod 10 Guide rod 11 Tie bar 11B Sliding bush 11X Multiple groove part 12 Motor 14 Reducer 16 Sprocket 18 Chain 60 Moving cylinder 60a Piston rod 100 Tie bar fixing device 110 Half nut 110X Multiple groove part 120 Half nut open / close cylinder 120a Piston 120b Piston rod 120H Head side 120R Rod side 121 End plate 122 Guide rod 123 Nut box 123A Through hole 124 Stopper 125 Topper 126 Guide block 127 Guide bar 128 Set bolt 130 Half nut moving cylinder 200 Tie bar nut attaching / detaching device 210 Tie bar nut 210a pin 210b pin 210c pin 210d pin 210e pin 220 Fixing plate 222 Vertical plate 230 Horizontal plate 231 Connecting plate 232 Stay 240 Hydraulic cylinder 240a Piston rod 242 Bracket 244 Metal fittings 244A Oval hole 250 Link mechanism 252 1st link 252a 1st link 252b 1st link 252c 1st link 254 2nd link 400 Mold clamping cylinder 400A Recess space 400B space 410 Piston 420 Bush 1000 Mold clamping device

Claims (2)

[Claims] 1. A direct pressure type die casting machine comprising a movable plate having a tie bar inserted therethrough and a fixed plate, wherein the movable plate is arranged so as to come in contact with and separated from the fixed plate, and the movable plate is moved and clamped. In the mold clamping device, the mold clamping device includes a moving cylinder for moving the movable platen forward and backward, a device for attaching and detaching a tie bar nut screwed to the tie bar, a tie bar removing device including a tie bar removing cylinder, and a mold closing operation end. The tie bar fixing device for fixing the movable plate afterwards to the tie bar, and the mold clamping cylinder for pressing the movable plate after mold closing against the fixed plate are provided on the outer periphery of the tie bar. The mold clamping cylinder is composed of a pair of two half nuts for gripping the carved multi-groove portion and a gripping means for the half nut, and the mold clamping cylinder is slidably disposed in a concave space formed in the side surface of the movable plate, and , Tip is front A mold clamping device for a die casting machine, comprising a piston that comes into contact with and presses the end surface of the half nut after gripping. 2. A tie bar nut attaching / detaching device is divided into two semi-circular arcs, one end of which is pivotally attached to a fixed platen and which is screwed with a threaded portion of the tie bar and which can be opened and closed, and each of the tie bar nuts. 2. The mold clamping device for a die casting machine according to claim 1, further comprising opening / closing means for the tie bar nut, which comprises a link mechanism consisting of a four-bar link that is pin-joined to the free end of the tie bar nut, and a hydraulic cylinder connected to the four-bar link. .