JPH07148806A - Clamping frame, clamping device, and clamping device for injection molding machine - Google Patents

Abstract

PURPOSE:To avoid the occurrence of a bending moment caused by a stress acting on a clamping frame, enhance an accuracy of a clamping operation, and make a device light in weight and small in size. CONSTITUTION:A clamping frame, a clamping device, and a clamping device for an injection molding machine are so constructed that a body 10 is used as the clamping frame of approximately an H shape, upper opposed parts 10a, 10b of the body 10 serve as clamping parts, and a balance cylinder 11 is provided between lower opposed parts 10c, 10d for balancing pressing forces of the opposed parts 10a, 10b, 10c, 10d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping frame, a mold clamping device, and a mold clamping device for an injection molding machine, and more particularly to a novel frame structure for a mold clamping device such as an injection molding machine, a die cast machine, a press machine or the like. Related to the major improvements.

[0002]

2. Description of the Related Art As a conventional frame structure for a mold clamping device used in an injection molding machine, a die cast machine or a press machine, there is, for example, a C-shaped frame structure shown in FIG. That is, FIG. 5 shows a horizontal type injection molding machine to which a C-shaped frame structure is applied. In FIG. 5, reference numeral 50 is a C-shaped frame whose cross-sectional shape and appearance are substantially C-shaped.
The first and second upper facing portions 10a and 10b, which are formed on the upper portion of 0 and are separated from each other, are arranged facing upward. A stationary platen 12 is vertically arranged inside the first upper facing portion 10a, and a horizontally arranged mold clamping cylinder 16 is provided on the second upper facing surface 10b. A movable platen 13 is vertically arranged at the tip of a piston rod 15 provided at 18 such that the movable platen 13 faces the fixed platen 12 via a rotary support shaft 7. The movable platen 13 horizontally reciprocates via a support body 17a on a guide rail 17 provided on an upper surface of an intermediate horizontal portion 50a formed between the first and second upper facing portions 10a and 10b of the C-shaped frame 50. It is movably supported.

A first mold part 14a and a second mold part 14b are provided inside the fixed plate 12 and the movable plate 13, respectively, and the mold 14 is formed by the first and second mold parts 14a and 14b. Are configured. On the vertical outer surface side of the fixed plate 12, and on the mold clamping cylinder 16 and the piston rod 1.
An injection device 27 is arranged on an extension line of a shaft line connecting the movable plate 13, the movable plate 13, the mold 14, and the fixed plate 12.

In the injection molding machine configured as described above, hydraulic pressure is applied to the piston 18 of the mold clamping cylinder 16 so that the movable platen 13 is moved through the piston rod 15 in accordance with the reciprocating movement of the piston 18 in the axial direction. Fixed plate 12
It approaches, pushes, and separates from. The mold 14 is opened and closed by the reciprocating movement of the movable platen 13, and when the mold 14 is closed, hydraulic pressure is further applied to the piston 18 in the closing direction of the mold 14, so that the mold 14 is formed on the dividing surface. The surface pressure is applied and the pressed state is maintained.

Next, in order to obtain a molded product, first, the mold 14 is used.
Is closed and a required surface pressure is further applied. Next, the molten molding material is injected from the injection device 27 into the mold 14, and after holding for a required time, the mold 14 is opened and the molded product is taken out. The above operations can be sequentially repeated to continuously produce molded products.

[0006]

Since the conventional one-piece frame for the mold clamping device is constructed as described above, the following problems exist. That is, when the mold 14 is closed and a required surface pressure is applied between the divided surfaces, a reaction force of the surface pressure acts on each of the upper facing parts 10a and 10b of the C-shaped frame 50, as shown in FIG. In addition, a bending moment acts on the cross section of the intermediate horizontal portion 50a of the C-shaped frame 50, a tensile force acts on its upper side, and a compressive force acts on its lower side. As a result, the upper facing portions 10a, 1 of the C-shaped frame 50
0b is deformed so that its optical ends open to each other, and fixed plate 1
2 and the vertical planes of the movable plate 13 facing each other were to be inclined. In addition, the movable plate 13 has a piston rod 15
It is possible to change so that the inner facing surface is always parallel to the fixed plate 12 by being provided at the tip end of the rotary shaft 7 via the rotary support shaft 7. The core is misaligned. That is, a deviation occurs between the divided surfaces of the mold 14 that is divided into two and is held on the inner facing surfaces of the fixed plate 12 and the movable plate 13, and the shape quality of the molded product is impaired. In order to reduce such deformation of the C-shaped frame 50 to the extent that it does not affect the product quality, the strength of the C-shaped frame 50 has been increased. It was larger and heavier than necessary. Also,
In such an integral type frame, a frame having a large mold clamping capacity is further increased in size and weight, so that it is not feasible and is only used in a small capacity mold clamping device.

The present invention has been made in order to solve the above problems, and has a structure in which the deformation amount of the frame is small and is applicable to a mold clamping device having a large mold clamping ability and a mold clamping frame. An object is to provide a device and a mold clamping device for an injection molding machine.

[0008]

A mold clamping frame according to the present invention has a first H-shaped main body having a substantially H-shaped main body and a first H-shaped main body facing away from each other. A fixed platen is vertically held, and a movable plate vertically arranged in the intermediate horizontal part of the main body is provided on the second upper facing part so as to face the fixed platen and to the intermediate horizontal part via a piston and a piston rod. While holding a mold clamping cylinder that reciprocates in the horizontal direction along the first and second lower facing portions that are spaced apart from each other in the lower portion of the main body, the first and second
The balance cylinder supported between the lower facing portions is provided.

More specifically, the mold clamping cylinder and the balance cylinder are adjusted so that the bending moment of the pressing force of the mold clamping cylinder against the intermediate horizontal portion of the main body and the bending moment of the pressing force of the balance cylinder are equal. The cylinder is arranged.

The mold clamping device according to the present invention comprises a main body for forming a mold clamping frame having a substantially H-shape, and the first and second upper facing portions of the first and second upper facing portions which are spaced apart from each other on the upper portion of the main body. (1) A fixed plate vertically held on the upper facing part and a horizontal plate held on the second upper facing part, and the tip of the piston rod approaches the center of the inner vertical surface of the fixed plate via a built-in piston. A mold clamping cylinder that horizontally reciprocates so as to press and separate; a movable plate that is vertically held at the tip of the piston rod of the mold clamping cylinder and that horizontally reciprocates along an intermediate horizontal portion of the main body; The balance cylinder is supported between the first and second lower facing portions which are spaced apart from each other in the lower portion.

More specifically, the product of the pressing force of the mold clamping cylinder and the vertical distance from the mold clamping cylinder to the intermediate horizontal portion, the pressing force of the balance cylinder, and the balance cylinder to the intermediate horizontal portion. The mold clamping cylinder and the balance cylinder are arranged so that the product of the vertical clamping distance and the vertical distance becomes equal.

More specifically, the pushing-side cylinder chamber of the mold clamping cylinder and the pushing-side cylinder chamber of the balance cylinder communicate with each other.

A mold clamping device for an injection molding machine according to the present invention comprises a main body for forming a mold clamping frame having an approximately H shape, and first and second upper facing surfaces which are spaced apart from each other on an upper portion of the main body. Fixed plate vertically held on the first upper facing part of the section and a horizontal plate held on the second upper facing part, and a piston rod is inserted through a built-in piston so that the tip of the piston rod faces the inner vertical surface of the fixed plate. A mold clamping cylinder that horizontally reciprocates so as to approach, press, and move away from the center, and a movable plate that is vertically held at the tip of the piston rod of the mold clamping cylinder and that horizontally reciprocates along the intermediate horizontal part of the main body. A balance cylinder that is held in the lower portion of the main body via first and second lower facing portions that are spaced apart from each other, and a frame that is integrally provided with the main body outside the vertical plane of the fixed plate. And the mold clamping An injection device in which the tip of the injection nozzle is horizontally reciprocally movable toward the fixed plate on the extension line of the horizontal reciprocating shaft of the piston rod of the Linda, and the injection device approaches and presses the center of the fixed plate. A second balance cylinder provided between a moving cylinder that horizontally reciprocates so as to separate, a first lower facing portion of the main body, and a frame provided outside the main body, and pressing of the mold clamping cylinder A first communication means for communicating the side cylinder chamber with the balance cylinder, and a second communication means for communicating the pressing side cylinder chamber of the moving cylinder with the second balance cylinder, and an intermediate horizontal position of the main body. The bending moment due to the pressing force of the mold clamping cylinder against the portion becomes equal to the bending moment due to the pressing force of the first balance cylinder, and the pressing force of the injection device is increased. And a bending moment due to the pressing force of the bending by the force moment second balancing cylinder is configured to have such a value equal.

[0014]

In the mold clamping frame and the mold clamping device according to the present invention, the fixed platen and the movable plate which respectively hold and face the two dies divided at the upper facing portions of the main body as the mold clamping frame having the substantially H shape. When the mold clamping cylinder presses against the board via the piston and piston rod, a pressing force is generated on the split surface of the mold, and the reaction force acts in the direction to push open the upper facing part of the main body, and the horizontal direction of the main body. A bending moment is applied to the part so that the part expands upward.
Also, when pressure is applied to the balance cylinder at the lower facing portion, both ends of the balance cylinder act to push open the lower facing portion of the main body, and the balance expands downward with respect to the intermediate horizontal portion of the main body, that is, the pressing force of the mold clamping cylinder. Apply a bending moment in the opposite direction to the case. It is necessary for the mold clamping cylinder to apply a required pressing force to the mold, and the bending moment acting in the middle horizontal part of the main body by this pressing force is almost the same as the opposite bending moment in the middle of the main body. By applying pressure to the balance cylinder so that it acts on the horizontal portion, the two bending moments cancel each other out in the middle horizontal portion of the main body, the bending moment does not act, and the tensile force acts on the entire cross section of the middle horizontal portion. . Therefore, the amount of deformation as a cantilever is very small in the upper facing part of the H-shaped body whose height is lower than the width, and the middle horizontal part is not bent and deformed. The facing part is not pushed open, and the piston rod of the mold clamping cylinder always presses in a state perpendicular to the center of the inner vertical surface of the fixed platen. Also, the pressing capacity and the arrangement are selected so that the product of the pressing capacity of each of the mold clamping cylinder and the balance cylinder and the distance to the intermediate horizontal portion of the main body becomes substantially equal, and the pressing side cylinder chamber of each cylinder is selected. By communicating with each other, the bending moments that the cylinders exert on the intermediate horizontal portion of the main body at the time of pressing become opposite to each other at the same time by the pressure source of one of the cylinders at the same time and always cancel each other out. Becomes

Further, in the mold clamping device for an injection molding machine,
In addition to the actions of the mold clamping cylinder and the balance cylinder described above, the product of the pressing ability of each of the injection cylinder acting on the upper outer surface of the main body and the second balance cylinder acting on the lower outer surface of the same side and the distance to the intermediate horizontal portion of the main body The pushing capacity and arrangement are selected so that the values of are almost equal, and the pushing side cylinder chambers of the cylinders are communicated with each other, so that the bending moments of the respective cylinders acting in the intermediate horizontal portion at the time of pushing are opposite to each other. It becomes the same value at the same time and always by the pressure source of either one of each cylinder.
It is offset and becomes zero.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a mold clamping frame, a mold clamping device, and a mold clamping device for an injection molding machine according to the present invention will be described in detail below with reference to the drawings. It should be noted that the same or equivalent parts as those of the conventional example will be described by attaching the same reference numerals. FIG. 1 is a front view with a partial cross-sectional view showing an embodiment in which the mold clamping device according to the present invention is applied to a horizontal injection molding machine, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. . In FIGS. 1 and 2, reference numeral 10 is a main body as a mold clamping frame, and the main body 10 has a substantially H shape whose height is lower than the width when viewed from the front, and has a predetermined length. By arranging the main bodies 10 having the dimension in the thickness direction of the front and rear in parallel, and engaging the main bodies 10 integrally at the intermediate horizontal portion 10A of the main body 10, as shown in FIG. , Substantially H-shaped.

The first and second upper facing portions 10a and 10b, which are spaced apart from each other on the upper portion of the main body 10, are fixed inside the first upper facing portion 10a so as to face the second upper facing portion 10b. The board 12 is held vertically. The second
A double-acting mold clamping cylinder 16 is horizontally held on the upper facing portion 10b such that its operating axis is perpendicular to the center of the fixed platen 12. A guide rail 17 is provided on the upper surface of the intermediate horizontal portion 10A of the main body 10, and a movable plate is provided on the guide rail 17 so as to face the fixed plate 12 and move toward and away from each other in a vertical state. 1
3 are arranged.

The movable platen 13 includes the mold clamping cylinder 16
Is connected to the tip of the piston rod 15. Mold parts 14a and 14b which are divided into two parts are respectively held on the vertically inward facing surfaces of the stationary platen 12 and the movable platen 13, and hydraulic pressure is applied to the mold clamping cylinder 16, whereby a piston 18, a piston rod 15, The mold part 14b forming the mold 14 is configured to approach, closely contact, press and separate from the mold part 14a via the movable platen 13.

A single-acting balance cylinder 11 is supported with its operating axis horizontal between the first and second lower facing portions 10c and 10d, which are formed on the lower portion of the main body 10 so as to be spaced apart from each other. . When one balance cylinder 11 is used, a supporting member 10f is provided in the depth direction of each of the lower facing portions 10c and 10d, and the supporting member 10f is provided.
Holds the balance cylinder 11 and supports the pressing.

The mold clamping cylinder 16 and the balance cylinder 11 are arranged such that the operating shafts 16a, 11a of the cylinders 16, 11 are located from the center of gravity P of the cross section of the intermediate horizontal portion 10A.
Up to the vertical distances L ₁ and L ₂ and the pressing forces of the cylinders 16 and 11 have the same value.
The size and vertical distance are selected. The mold clamping cylinder 16 is provided with a second hydraulic pipe 21 from the hydraulic device 19 to the pressing chamber 16b via the switching valve 20 and the first hydraulic pipe 21a.
Pressure oil is supplied to or discharged from the suction chamber 16c via b. Similarly, the balance cylinder 11 is supplied with pressure oil from the hydraulic device 19 via the switching valve 20 and the third hydraulic pipe 21c branched from the hydraulic pipe 21a, and is formed by the first and third hydraulic pipes 21a and 21c. A first communicating means 60 is provided for communicating between the pressing chamber 16b of the tightening cylinder 16 and the pressing side cylinder chamber of the balance cylinder 11.

The mold clamping device 1 configured as described above is arranged on a frame 22 common to the injection device 27, and the mold clamping device 1 is mounted on the frame 22 as a main body 10 as a mold clamping frame. The first lower facing surface portion 10c is fixedly held, and the second lower facing surface portion 10d on the mold clamping cylinder 16 side is slidably held via the sliding plate 23 in the axial direction of the balance cylinder 11.

On the frame 22 on both side surfaces in the sliding direction of the second lower facing portion 10d, stoppers 24 holding bolts moving forward and backward in the sliding direction with projecting members are provided. The movement range of the main body 10 is restricted. An injection device is arranged on the frame 22 on the back surface of the fixed plate 12, with its axis aligned with the extension line of the axis of the cylinder piston 15, with the injection nozzle 27a of the injection device 27 facing the fixed plate 12 side. There is.

In the injection molding machine configured as described above, a case of actually performing an injection molding operation will be described. First, the piston 18 of the mold clamping cylinder 16 is retracted, the movable platen 13 is separated from the fixed platen 12, and the two halves of the mold 14 are opened, that is, the mold open state. 19 to the first and third hydraulic pipes 21a,
Pressure oil is supplied to the pressing chamber 16b of the mold clamping cylinder 16 and the balance cylinder 11 via 21c. At the same time, pressure oil is discharged from the suction chamber 16c of the mold clamping cylinder 16 through the hydraulic pipe 21b.

The pressure oil supplied to the pressing chamber 16b pushes the piston 18 to push out the piston rod 15,
The movable platen 13 advances along the guide rails 17 in the direction toward the fixed platen 12 until the divided surfaces of the mold 14 come into close contact with each other. After the mold 14 is brought into close contact, that is, in the mold closed state, a predetermined pressing force is applied to the divided surfaces.
Generate high pressure and transmit the high pressure through pressure oil.

Next, the mold 1 is closed with a predetermined pressing force.
4 to the die 1 from the rear of the fixed plate 12
Inject the injection material into No. 4. After a predetermined time from this injection operation, the switching valve 20 is operated to supply pressure oil from the hydraulic device 19 to the suction chamber 16c of the mold clamping cylinder 16 via the second hydraulic pipe 21b, and at the same time from the pressing chamber 16b to the first chamber. Pressure oil is discharged through the hydraulic pipe 21a. By the operation of the switching valve 20, the pressure oil supplied to the suction chamber 16c pushes the piston 18 to retract the piston rod 15, and the movable platen 13 moves along the guide rail 17 in the direction away from the fixed plate 12. Then, the mold 14 is separated at the dividing surface and retracts to a predetermined interval.

After the mold 14 has been retracted, that is, the mold has been opened, the molded product remaining in the mold 14a held on the fixed platen 12 is taken out to complete one injection cycle. By repeatedly executing the above injection cycle, molded products can be continuously produced. As described above, while the injection molding machine operates for one injection cycle, the mold clamping cylinder 1
The pressure oil of the same pressure always acts on the pressing chamber 16b of No. 6 and the balance cylinder 11. The pressure acting on the pressing chamber 16b causes a bending moment to inflate upward on the intermediate horizontal portion 10A of the main body 10 as the mold clamping frame, while the pressure acting on the balance cylinder 11 is the intermediate horizontal portion 10A. Bending moments that inflate downward are applied, but since the two bending moments have the same magnitude and opposite acting directions, they cancel each other out to cancel each other, and the intermediate horizontal portion 10A is affected by the pressure of the pressure oil. Only horizontal tension acts.

The tensile force applied to the intermediate horizontal portion 10A causes the intermediate horizontal portion 10A to elastically deform and expand, but the second lower facing portion 10d slides on the slide plate 23,
It moves outward by the same amount as the amount of expansion of the intermediate horizontal portion 10A. Therefore, the movement amount of the second lower facing portion 10d is regulated by the stopper 24, and the injection cycle is repeated within a range not exceeding this regulation.

FIG. 3 is a partially sectional front view showing another embodiment in which the mold clamping device according to the present invention is applied to a horizontal injection molding machine, and FIG. 4 is an arrow IV-IV in FIG. FIG. It should be noted that the same or equivalent portions as those in FIG. In this embodiment, the intermediate horizontal portion 1 of the main body 10 as the mold clamping frame in the embodiment shown in FIGS.
The 0B portion is formed into a rectangular box shape having a space 10X, and a pair of balance cylinders 11a and 11b are individually provided between the intermediate horizontal portion 10B and the respective lower facing portions 10c and 10d, and further in front and in the back. A second balance that is provided individually and that corresponds to the pressing force of the injection device 27 against the mold 14 between the outside of the first lower facing portion 10c on the fixed plate 12 side and the external fixing portion 70 provided on the frame 22. A cylinder 11 'is newly added.

That is, in the vertical portions on both sides of the main body 10, the pair of balance cylinders 11a and 11b operate from the deformation fulcrums C and D on the stationary platen 12 side and the mold clamping cylinder 16 side, respectively. The product of the vertical distance to the shaft and the pressing force is configured to be equal to the product of the vertical distance from the deformation fulcrums C and D to the operating axis of the mold clamping cylinder 16 and the pressing force of the mold clamping cylinder 16. . Similarly, the second balance cylinder 11 ′ is moved from the deformation fulcrum C on the fixed plate 12 side to the second balance cylinder 11 ′.
The product of the vertical distance to the working axis and the pressing force is the deformation fulcrum C
To the tip position of the injection nozzle 27a of the injection device 27 and the product of the pressing force of the injection device moving cylinder 27A to be described later. The above-described injection device moving cylinder 27A is provided in the frame 22 for moving the injection device 27 forward and backward and pressing it against the fixed platen 12.

The intermediate horizontal portion 10A also has a rectangular box shape in the depth direction and constitutes the frame of the main body 10 itself. The third hydraulic pipe 21c is connected to each balance cylinder 11a, 11b. Further, the moving cylinder 2 of the injection device is connected to the second balance cylinder 11 ′ via the second hydraulic device 19a and the second switching valve 20a.
A fifth hydraulic pipe 21e branched from the fourth hydraulic pipe 21d connected to the pressing chamber of 7A is connected. Further, the movement of each of the lower facing portions 10c and 10d is restricted by a stopper 24 provided on the frame 22. Therefore, the fourth and fifth hydraulic pipes 21d and 21e constitute second communicating means 61 for communicating the moving cylinder 27A and the pressing side cylinder space of the second balance cylinder 11 '.

When performing the injection molding operation in the injection molding machine configured as described above, first, the action of the mold clamping cylinder 16 is similar to that of the above-described embodiment shown in FIGS. Only a tensile force is generated in the intermediate horizontal portion 10A, and the intermediate horizontal portion 10A only elastically deforms in the horizontal direction. Further, in the injection device 27, the tip of the injection nozzle 27 a is in close contact with the mold 14 a from the back of the fixed platen 12, and the injection device moving cylinder 27
The upper facing portions 10a, 10 of the main body 10 are pressed by A.
b receives a pushing force in the direction of the mold clamping cylinder 16. The second balance cylinder 11 ′ cancels this pressing force by always applying the same pressing force to the lower facing portions 10 c and 10 d of the main body 10. Although the embodiment in which the present invention is applied to the horizontal injection molding machine has been described above, the present invention is not limited to the horizontal injection molding machine, and a vertical injection molding machine, a die casting machine, a pressing machine, etc. It is applicable as a mold clamping device regardless of the mold.

[0032]

Since the mold clamping frame, the mold clamping device, and the mold clamping device for the injection molding machine according to the present invention are configured as described above, the following effects can be obtained. (1) The main body as a mold clamping frame has a substantially H shape,
Since it is configured to cancel the stress generated in the vertical facing portion of the character-shaped main body, the vertical degree of the vertical facing portion does not always change, and the mold clamping portion is always brought into close contact with and pressed at the correct position. (2) Therefore, the quality of the shape of the product produced by pressing is always constant, and a good quality product is produced. (3) Since the bending moment due to the stress generated in the main body as the mold clamping frame is offset to be zero, the strength against bending due to the bending moment is not required, and the mold clamping frame can be lightweight and downsized. (4) Therefore, conversely, it becomes possible to relatively increase the capability as compared with the conventional one. (5) When applied to an injection molding machine, it becomes an injection molding machine without a tie bar, and workability is greatly improved.

[Brief description of drawings]

FIG. 1 is a front view, partly in section, showing an embodiment in which a mold clamping device according to the present invention is applied to a horizontal injection molding machine.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a front view showing another embodiment of FIG.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is a front view with a partial cross-sectional view showing a conventional mold clamping device.

[Explanation of symbols]

 10 main body 10A, 10B middle horizontal part 10a, 10b first, second upper facing part 10c, 10d first, second lower facing part 11 balance cylinder 11 'second balance cylinder 12 fixed plate 13 movable plate 15 piston rod 16 type Tightening cylinder 27a Injection nozzle 27A Moving cylinder 60 First communication means 61 Second communication means 70 External fixing part

Claims (6)

[Claims] 1. Fixed to the first upper facing portion (10a) of the first and second upper facing portions (10a, 10b) which are separated from each other on the upper portion of the main body (10) having a substantially H shape. A panel (12) is held vertically, and the second upper facing part (10b) faces the fixed plate (12) and is vertically arranged in the intermediate horizontal part (10A) of the main body (10). Put the board (13) on the piston (18) and piston rod (15).
A first and a second portion, which are configured to hold a mold clamping cylinder (16) that horizontally reciprocates along the intermediate horizontal portion (10A) via the The lower facing portions (10c, 10d) include the first and second lower facing portions (10
A mold clamping frame, characterized in that a balance cylinder (11) supported between c and 10d) is provided. 2. The bending moment due to the pressing force of the mold clamping cylinder (16) against the intermediate horizontal portion (10A) of the main body (10) and the bending moment due to the pressing force of the balance cylinder (11) have the same value. If possible, use the mold clamping cylinder (1
The mold clamping frame according to claim 1, wherein 6) and the balance cylinder (11) are arranged and configured. 3. A main body (10) for forming a mold clamping frame having a substantially H-shape, and first and second upper facing portions (10a, 10a, 10a, A fixing plate (12) vertically held on the first upper facing portion (10a) of 10b);
The piston rod (15) is horizontally held by the second upper facing portion (10b), and the tip of the piston rod (15) approaches and presses the center of the inner vertical surface of the fixed plate (12) through a built-in piston (18). -A mold clamping cylinder (16) that horizontally reciprocates so as to separate from each other, and is vertically held at the tip of the piston rod (15) of the mold clamping cylinder (16) and is attached to the intermediate horizontal portion (10A) of the main body (10). A balance cylinder (13) supported horizontally between a movable plate (13) horizontally reciprocating and first and second lower facing parts (10c, 10d), which are spaced apart from each other in the lower part of the main body (10). 11) A mold clamping device comprising: 4. The product of the pressing force of the mold clamping cylinder (16) and the vertical distance from the mold clamping cylinder (16) to the intermediate horizontal portion (10A), and the pressing force of the balance cylinder (11). The mold clamping cylinder (16) and the balance cylinder (11) are arranged so that the product of the balance cylinder (11) and the vertical distance from the intermediate horizontal portion (10A) is equal to the product. The mold clamping device according to claim 3. 5. The mold clamping device according to claim 3 or 4, wherein the mold cylinder of the mold clamping cylinder (16) communicates with the cylinder mold of the balance cylinder (11). . 6. A body (10) for forming a mold clamping frame having a substantially H-shape, and a first body (10) separated from each other on an upper portion of the body (10).
A fixed platen (12) vertically held by the first upper facing part (10a) of the second upper facing part (10a, 10b) and horizontally held by the second upper facing part (10b) and incorporated therein. A mold clamping cylinder (16) for horizontally reciprocating the piston rod (15) through the piston (18) so that the tip of the piston rod (15) approaches, pushes, or separates from the center of the inner vertical surface of the fixed plate (12), A movable plate (13) vertically held at the tip of a piston rod (15) of the mold clamping cylinder (16) and horizontally reciprocating along an intermediate horizontal portion (10A) of the main body (10); ), A balance cylinder (11) held via first and second lower facing parts (10c, 10d), which are spaced apart from each other, and the outside of the fixed plate (12) in the vertical plane. On the frame (70) provided integrally with the main body (10) and above the mold clamping cylinder (16)
An injection device (27) arranged so that the tip of the injection nozzle (27a) can be horizontally reciprocated toward the fixed plate (12) on an extension of the horizontal reciprocating movement axis of the piston rod (15), A moving cylinder (2) that horizontally reciprocates (27) so as to approach, press, and move away from the center of the fixed plate (12).
7A), the first lower facing portion (10c) of the body (10), and the body (10)
A second balance cylinder (11 ') provided between the frame (70) provided outside, a communication between the pressure side cylinder chamber (16b) of the mold clamping cylinder (16) and the balance cylinder (11). The first communication means (6
0) and a second communication means (61) for communicating the pressing side cylinder chamber of the moving cylinder (27A) with the second balance cylinder (11 '), and the intermediate horizontal portion of the main body (10). The bending moment due to the pressing force of the mold clamping cylinder (16) with respect to (10A) and the bending moment due to the pressing force of the first balance cylinder (11) have the same value, and the bending moment due to the pressing force of the injection device (27). A mold clamping device for an injection molding machine, characterized in that the bending moment due to the pressing force of the second balance cylinder (11 ') has the same value.