JPH06297525A - Levelling controller for vertical clamping device and its control method - Google Patents

Abstract

PURPOSE:To achieve improvement of precision in levelling by a method wherein response speed of levelling regulating operation can be raised. CONSTITUTION:A movable platen 3 is preliminarily pushed on a fixed platen side, and each levelling regulation rod 14 is brought into contact with each corresponding rod receiving part 29 to regulate a zero point. Thereafter, clamping operation is carried out with a clamping cylinder 6 under a state wherein each levelling regulation rod 14 is sent out respectively by the same distance toward each rod receiving part 29 at a transfer position of the movable platen 3. Then, by bringing all levelling regulation rods 14 in contact with the rod receiving part 29, levelling regulation is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical type for adjusting the leveling between a movable platen and a fixed platen of a vertical type mold clamping device used for clamping a mold for injection molding a synthetic resin molded product. TECHNICAL FIELD The present invention relates to a leveling control device for a mold clamping device and a control method thereof.

[0002]

2. Description of the Related Art Generally, for example, a vertical mold clamping device used for clamping a molding die for injection molding a synthetic resin molded article has a structure disclosed in Japanese Patent Laid-Open No. 1-264823. Are known. Here, in the vertical mold clamping device, a movable platen that holds the upper mold of the injection molding mold,
A fixed platen for holding the lower mold is provided, and a mold clamping cylinder for vertically moving the movable platen with respect to the fixed platen is provided. The mold clamping cylinder presses the movable platen toward the fixed platen to clamp between the upper mold and the lower mold.

Further, the vertical mold clamping device is provided with four leveling cylinders formed by hydraulic cylinders at the four corners of the fixed platen, and the posture of the movable platen is fixed by these four leveling cylinders. A leveling adjustment device is provided for performing the leveling adjustment in a state parallel to the side.

Further, a pressure detector is connected to each leveling cylinder. Then, based on the detection signal from the pressure detector, the pressure control valve for controlling the pressure of the mold clamping cylinder is controlled to adjust the mold opening of the mold, the mold clamping speed, and the like, and to adjust the four leveling cylinders. Leveling adjustment is performed by performing control so that the posture of the movable platen is parallel to the fixed platen side.

[0005]

In the conventional structure described above, since the leveling cylinder formed by the hydraulic cylinder is used as the driving means of the leveling adjusting device of the vertical mold clamping device, the hydraulic oil is compressed. There is a problem that the response speed becomes slow due to the sex.

Further, there is also a problem that the leveling accuracy becomes relatively low due to changes in the physical properties of the hydraulic oil due to temperature changes. For example, when the moving speed of the movable platen is 5 mm / s or less, the leveling accuracy of the movable platen is limited to within ± 50 μ.

The present invention has been made in view of the above circumstances, and a leveling control device for a vertical mold clamping device capable of increasing the response speed of the leveling adjustment work and improving the leveling accuracy, and the same. It is intended to provide a control method.

[0008]

According to a first aspect of the present invention, an upper die of an injection molding die is held by a movable platen and a lower die thereof is held by a fixed platen, and the movable platen is moved up and down with respect to the fixed platen. It is mounted on a vertical mold clamping device equipped with a mold clamping cylinder that is driven to press the movable platen toward the fixed platen side to clamp between the upper mold and the lower mold, and adjust the posture of the movable platen to In a leveling control device for a vertical mold clamping device that adjusts the leveling in a state parallel to the fixed platen side, a plurality of leveling adjustment rods mounted on the movable platen so as to be movable along the moving direction of the movable platen. A ball-screw type feed mechanism unit for vertically moving each leveling adjustment rod in the vertical movement direction of the movable platen; A plurality of rod receiving portions, which are arranged to face and separate from the leveling adjusting rods, are in contact with each of the leveling adjusting rods, and a pressure detecting means for detecting a contact pressure of each of the leveling adjusting rods of each rod receiving portion. And controlling the operation of the feed mechanism section based on the detection signal from each pressure detection means, pressing the movable platen to the fixed platen side in advance, in a state where the upper mold is brought into contact with the lower mold, The leveling adjustment rods are brought into contact with the corresponding rod receiving portions to perform zero-point adjustment, and then the movable platen is moved to a position where the upper die is separated from the lower die, at the moving position. The adjustment rods are sent out toward the rod receiving portions by the same amount, and in this state, the movable platen is moved by the mold clamping cylinder. When performing the mold clamping operation of pressing to the fixed platen side, before contacting the upper mold with the lower mold, each of the leveling adjustment rods is contacted with the rod receiving portion side, and each of the leveling adjustment rods is connected with the rod. A leveling control device for a vertical mold clamping device, comprising: a control unit that adjusts the leveling between the movable platen and the fixed platen side by bringing all of them into contact with a receiving portion.

According to a second aspect of the present invention, the movable platen for holding the upper die of the injection molding die is pressed against the fixed platen side for holding the lower die for injection molding to bring the upper die into contact with the lower die. The moving platen moving step for zero point adjustment, and the leveling adjustment rods of the plurality of ball screw type feed mechanism units mounted so as to be movable in the up-and-down movement direction of the movable platen are provided on the fixed platen side. The zero point adjustment step of bringing the movable die into contact with the lower portion and performing the zero point adjustment, and after the zero point adjustment, move the movable platen to a position where the upper die is separated from the lower die, and move each of the leveling adjustment rods. A leveling adjustment preparation step of sending the same amount toward each rod receiving portion side and a mold clamping operation of pressing the movable platen toward the fixed platen side by the mold clamping cylinder are performed. In addition, before the upper die contacts the lower die, the leveling adjustment rods are all brought into contact with the rod receiving portion side by the pressing force from the die clamping cylinder, so that the movable platen and the fixed platen side are contacted with each other. And a leveling adjustment step for performing leveling adjustment between the two.

[0010]

[Function] During leveling adjustment, the movable platen is pressed against the fixed platen side in advance to bring the upper mold into contact with the lower mold, and in this state, the leveling adjustment rods of the plurality of ball screw type feed mechanism units are connected to the plurality of rod receivers on the fixed platen side. Contact each other to adjust the 0 point, and after adjusting the 0 point, move the movable platen to the position where the upper die is separated from the lower die, and move each leveling adjustment rod to each rod receiving portion side. When the mold clamping operation is performed by pressing the movable platen toward the fixed platen side by the mold clamping cylinder, the leveling is performed by the pressing force from the mold clamping cylinder before the upper mold contacts the lower mold. The leveling adjustment between the movable platen side and the fixed platen side is performed by bringing the adjustment rod into full contact with the rod receiving portion side.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows, for example, a schematic configuration of the entire vertical mold clamping device 1. The vertical mold clamping device 1 is provided with a movable platen 3 that holds an upper mold 2 of an injection molding die (molding die) and a fixed platen 5 that holds a lower mold 4, and the movable platen 3 is also provided. There is provided a mold clamping cylinder 6 that drives the movable platen 3 toward the fixed platen 5 side by vertically moving the movable platen 5 against the fixed platen 5 and clamps between the upper mold 2 and the lower mold 4.

Here, the fixed platen 5 is installed on, for example, a fixed floor surface. 4 on the upper surface of the fixed platen 5
Columns 7 are provided at the corners so as to project, as shown in FIG. Further, a cylinder support member 8 is fixed to the upper ends of the four columns 7. And the mold clamping cylinder 6
Is fixed to the central portion of the cylinder support member 8.

Further, the vertical mold clamping device 1 has a movable platen 3
A leveling control device 11 for leveling and adjusting the posture to be parallel to the fixed platen 5 side is mounted. In this leveling control device 11, four upper leveling units 12 mounted on the movable platen 3 side and four lower leveling units mounted on the fixed platen 5 side and provided corresponding to the respective upper leveling units 12 respectively. And 13 are provided. The four upper leveling units 12 are respectively arranged inside the four columns 7 as shown in FIG.

Further, as shown in FIG. 3, each upper leveling unit 12 is provided with a leveling adjusting rod 14 mounted on the movable platen 3 so as to be movable along the ascending / descending direction of the movable platen 3, and this leveling adjusting rod 14. A ball-screw type feed mechanism unit 15 is provided which moves up and down along the direction in which the movable platen 3 moves up and down.

Here, the leveling adjusting rod 14 has a male screw-shaped screw shaft portion 16 which constitutes a ball screw on the upper side,
The spline shaft portions 17 are provided on the lower side. Further, the ball screw type feed mechanism section 15 is provided with a ball screw section 18 and a spline bearing section 19 which are fixed to the movable platen 3, and a drive motor 20 for rotationally driving the leveling adjustment rod 14. ing. Further, a speed reducer 21 such as a planetary gear unit or a cyclo speed reducer is interposed between the drive motor 20 and the leveling adjustment rod 14.

A unit mounting plate 22 is fixed to the upper surface of the movable platen 3. Guide shafts 23 project from four corners of the unit mounting plate 22, respectively. Further, as shown in FIG. 5, a guide plate 24 for holding the speed reducer 21 is attached to these four guide shafts 23 so as to be able to move up and down. The drive motor 20 is attached to the guide plate 24 via a motor attachment member 25.

Further, the rotary shaft 20a of the drive motor 20 is connected to the high speed shaft on the input side of the speed reducer 21. The leveling adjustment rod 1 is attached to the low speed shaft on the output side of the speed reducer 21.
The upper end of the screw shaft portion 16 of No. 4 is connected via a connecting member 26. Then, when the drive motor 20 is driven, the rotational force from the drive motor 20 is transmitted to the screw shaft portion 16 of the leveling adjustment rod 14 while being reduced in speed by the speed reducer 21, and the ball screw portion is rotated as the screw shaft portion 16 rotates. The screw shaft portion 16 is moved up and down by the screwing operation of the female screw portion in 18 along the ball movement.
At this time, as the leveling adjustment rod 14 is moved up and down, the guide plate 24 is moved up and down along the four guide shafts 23, so that the drive motor 20 and the speed reducer 21 are moved up and down together with the leveling adjustment rod 14. Has become.

The lower end portion of the screw shaft portion 16 of the leveling adjusting rod 14 is connected to the upper end portion of the spline shaft portion 17 via a bearing box 28 having a double thrust ball bearing 27 built therein as shown in FIG. ing. The double thrust ball bearing 27 in the bearing box 28 absorbs the rotational movement of the screw shaft portion 16 of the leveling adjustment rod 14, and only the ascending / descending movement is transmitted to the spline shaft portion 17 side, and the spline shaft portion 17 is The spline bearing portion 19 is guided to move up and down.

In the lower leveling unit 13, as shown in FIG. 4, the leveling adjustment rods 14 are arranged so as to face each other with a space therebetween.
There are provided a plurality of rod receiving portions 29 that come into contact with the rod receiving portions 29, and a load sensor (pressure detecting means) 30 that detects a contact pressure of each leveling adjustment rod 14 coming into contact with each rod receiving portion 29. A spacer having an appropriate thickness may be mounted between the upper leveling unit 12 and the lower leveling unit 13 according to the thickness of the injection molding die.

Further, the lower leveling unit 13
A hydraulic cylinder 31 for preventing damage to the leveling control device 11 when an overload is applied is attached to the. And, this hydraulic cylinder 31 has this hydraulic cylinder 31
A hydraulic control circuit (not shown) for keeping the internal hydraulic pressure constant is connected. The hydraulic cylinder 31 does not necessarily have to be provided.

A mold clamping force control device (control means) 32 is connected to the load sensor 30. A hydraulic control valve 33 for controlling the operation of the mold clamping cylinder 6 and a speed servo controller 34 for controlling the operation of the drive motor 20 are connected to the mold clamping force control device 32.

When the vertical mold clamping device 1 is used, the mold clamping force control device 32 and the speed servo control device 34 are controlled based on the detection signals from the respective load sensors 30, and the following vertical mold clamping device is controlled. The leveling control of the device 1 is performed.

That is, at the time of the mold clamping operation between the upper mold 2 and the lower mold 4 of the injection molding mold, first, the leveling control device 1
The zero point of 1 is adjusted. At the time of this 0-point adjustment, the movable platen 3 is lowered by the mold clamping cylinder 6 and moved to the mold clamping position where the upper mold 2 comes into contact with the lower mold 4 (movable platen moving process for 0-point adjustment). In this manner, when the upper die 2 is in contact with the lower die 4, the posture of the movable platen 3 is leveled and adjusted so as to be parallel to the fixed platen 5 side. At this time, the leveling adjustment rods 14 of the four upper leveling units 12 are raised in advance, and when the upper die 2 comes into contact with the lower die 4, the leveling adjustment rods 14
Are made to stand by at appropriate positions where they do not contact the rod receiving portion 29 of the lower leveling unit 13.

Next, the four drive motors 20 are driven while the movable platen 3 is held at the mold clamping position, and the leveling adjustment rods 14 are respectively lowered and brought into contact with the rod receiving portions 29. In this case, the drive motor 20 is stopped when the load sensor 30 detects that each leveling adjustment rod 14 is in contact with the rod receiving portion 29 (zero-point adjustment step). Then, the position of each leveling adjustment rod 14 at this time becomes the 0-point adjustment position,
The zero point adjustment work is completed.

The above-mentioned zero point adjustment is carried out with the upper die 2 in contact with the lower die 4, but this may be done with the upper die 2 simply touching the lower die 4. Alternatively, a fixed mold clamping force may be applied between the upper mold 2 and the lower mold 4.

It should be noted that this zero-point adjustment does not necessarily have to be performed every time before performing mold clamping. For example, the operation may be performed once at the start of operation of the day or occasionally during continuous operation.

Further, after the 0-point adjustment work is completed, the movable platen 3 is lifted by the mold clamping cylinder 6 while the leveling adjustment rods 14 are held at the 0-point adjustment positions, and the upper mold of the injection molding die is lifted. A mold opening operation for pulling 2 away from the lower mold 4 is performed.

Then, the four drive motors 20 are driven again at the mold open position, and the four leveling adjusting rods 1 are moved.
A leveling adjustment preparation operation for lowering 4 by the same amount (for example, 100 mm) is performed (leveling adjustment preparation step). The lowering operation of the leveling adjustment rod 14 at this time may be performed during the mold opening operation.

After the leveling adjustment preparation operation is completed, the mold clamping cylinder 6 carries out a regular mold clamping operation in which the movable platen 3 is lowered from the mold opening position to the mold clamping position. At the initial stage of this mold clamping operation (until the leveling adjustment rod 14 contacts the rod receiving portion 29 of the lower leveling unit 13 from the mold opening position), an appropriate initial mold clamping force smaller than the final mold clamping force (for example, the final mold clamping force). Mold clamping force is 200ton
In this case, the mold clamping cylinder 6 is driven in a state of generating 40 to 20 tons), and the movable platen 3 is lowered from the mold open position.

When the movable platen 3 is lowered by the initial mold clamping force, each leveling adjusting rod 14 is brought into contact with the rod receiving portion 29 before the upper mold 2 of the injection molding mold comes into contact with the lower mold 4. At this time, the upper mold 2 and the lower mold 4 of the injection molding die are separated by, for example, about 20 to 30 mm.

The state where each leveling adjusting rod 14 is in contact with the rod receiving portion 29 is detected based on the detection signal from each load sensor 30. Here, when the contact states of the leveling adjustment rods 14 are detected from the four load sensors 30 at the same time, it is determined that the posture of the movable platen 3 is leveled and adjusted to be parallel to the fixed platen 5 side. To be done.

In this case, subsequently, the following mold clamping operation is performed with the lower ends of the four leveling adjusting rods 14 kept in contact with the rod receiving portions 29, respectively.
That is, at the time of this mold clamping operation, an ascending operation is performed simultaneously with the lowering operation of the movable platen 3 by the mold clamping cylinder 6 and at the same time, in synchronization with the four, to raise the leveling adjustment rod 14. At this time, the amount of upward movement of each leveling adjustment rod 14 is controlled so as to match the amount of downward movement of the movable platen 3.

Further, during this mold clamping operation, as shown in FIG. 7, the detection value F ₂ from each load sensor 30 is maintained within an allowable pressure range, for example, at an appropriate set pressure (10 ton per one) P _S1 or less. The descending operation is continued under the condition that it is confirmed that the condition (0 <F ₂ <P _S1 ) is satisfied. Note that FIG.
In the figure, F ₀ represents the change characteristic of the mold clamping force by the mold clamping cylinder 6.

Further, during the mold clamping operation, when a state in which the detected value F ₂ from any of the load sensors 30 rises above the set pressure P _S1 is detected, an excessively large detected value F ₂ is detected. Leveling By increasing the amount of upward movement of the adjusting rod 14, control is performed so that the detection value F ₂ from each load sensor 30 is maintained within the allowable pressure range.

Then, the upper mold 2 of the injection mold is the lower mold 4
The maximum pressure is applied to the mold clamping cylinder 6 at the time of contact with (the stroke of the mold clamping cylinder 6 reaches the maximum value S _max ), and the final mold clamping force (for example, about 200 tons) P _max.
The mold clamping operation is continued in the state where the pressure is generated, and injection molding is performed in the mold in this mold clamping state.

When the movable platen 3 is lowered by the initial mold clamping force, the contact state of the leveling adjustment rod 14 is detected first by any one of the four load sensors 30.
From the remaining load sensor 30, the leveling adjustment rod 1
When the contact state of No. 4 is not detected, it is determined that the movable platen 3 is in an inclined state in which the movable platen 3 is inclined from a position parallel to the fixed platen 5 side. This occurs, for example, when the sliding resistances of the four columns 7 are different, or when the position where the pressing force of the mold clamping cylinder 6 acts is slightly deviated from the center.

At this time, the mold clamping cylinder 6 is driven in a state of generating an appropriate middle mold clamping force smaller than the final mold clamping force (for example, when the final mold clamping force is 200 tons, about 40 tons or less of 20% thereof). To be done. The middle mold clamping force acts on each leveling adjusting rod 14 with a pressing force that does not damage the ball screw portion 18, for example, 10 ton or less per one.

When a middle mold clamping force is applied from the mold clamping cylinder 6 in a state where the movable platen 3 is tilted with respect to the fixed platen 5 side, the rod is at that point due to this mold clamping force. The leveling adjustment rod 14 that is in contact with the receiving portion 29 is held as it is, and the movable platen 3 is pressed while the other leveling adjustment rods 14 are pressed in the direction in which they contact the rod receiving portion 29. It Therefore, the posture of the movable platen 3 is corrected to be parallel to the fixed platen 5 side by the middle mold clamping force of the mold clamping cylinder 6, and the four leveling adjusting rods 1
All 4 are brought into contact with the rod receiving portion 29 (leveling adjustment step).

Here, when the contact state of the leveling adjustment rod 14 is detected from the four load sensors 30, the posture of the movable platen 3 is adjusted to be parallel to the fixed platen 5 side. To be judged. At this time, if the contact state of the leveling adjustment rods 14 is not detected from the four load sensors 30, an alarm is issued, and the leveling adjustment rods 14 in which the contact state is detected are raised to raise the four rods. The leveling adjusting rod 14 is entirely brought into contact with the rod receiving portion 29.

Furthermore, four leveling adjustment rods 14
All come into contact with the rod receiving portion 29, and after the leveling adjustment is completed, the mold clamping operation similar to the above-described mold clamping operation is performed.

Therefore, in the above-mentioned structure, the upper leveling unit 12 has a ball screw type feed mechanism 15
Since the ball screw type feed mechanism unit 15 is driven by the drive motor 20 to drive the leveling adjustment rod 14 up and down along the moving direction of the movable platen 3, the ball screw type feed mechanism unit 15 is driven. The posture of the movable platen 3 can be leveled and adjusted with high precision (about 5 μm) in a state parallel to the fixed platen 5 side. Therefore, unlike when using a leveling cylinder formed by a hydraulic cylinder, there is no risk of variations in leveling accuracy due to changes in the physical properties of the hydraulic oil, and compared to when using a leveling cylinder formed by a hydraulic cylinder. It is possible to improve the leveling accuracy.

Further, in the ball screw type feed mechanism portion 15, the ball movement between the female screw portion in the ball screw portion 18 is accompanied by the rotation of the screw shaft portion 16 of the leveling adjusting rod 14 which is rotationally driven by the drive motor 20. Since the leveling adjusting rod 14 is mechanically fed by the screwing operation, there is no possibility that the response speed is slowed due to the compressibility of the hydraulic oil as in the case of using the leveling cylinder formed by the hydraulic cylinder. Therefore, the response speed of the leveling adjustment work can be increased as compared with the case where the leveling cylinder formed by the hydraulic cylinder is used. It should be noted that the present invention is not limited to the above-mentioned embodiments, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

[0043]

According to the present invention, the response speed of the leveling adjustment work can be increased and the leveling accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an entire vertical mold clamping device according to an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement state of a leveling adjustment rod mounted on a movable platen.

FIG. 3 is a side view showing an upper leveling unit.

FIG. 4 is a side view showing a lower leveling unit.

FIG. 5 is a side view showing a partial cross section of a connecting portion between a drive motor and a ball screw type feeding mechanism portion.

FIG. 6 is a vertical sectional view showing a connecting portion of a spline shaft.

FIG. 7 is a characteristic diagram showing a change characteristic of a mold clamping force by a mold clamping cylinder and a change characteristic of a pressing force from a leveling adjustment rod.

[Explanation of symbols]

2 ... Upper mold, 3 ... Movable platen, 4 ... Lower mold, 5 ... Fixed platen, 6 ... Mold clamping cylinder, 14 ... Leveling adjusting rod, 15 ... Ball screw type feed mechanism part, 29 ... Rod receiving part, 30 ... Load Sensor (pressure detection means), 32 ... Mold clamping force control device (control means).

Claims (2)

[Claims] 1. An upper mold of an injection molding mold is held by a movable platen, and a lower mold is held by a fixed platen, and the movable platen is driven up and down with respect to the fixed platen to move the movable platen to the fixed platen. Mounted on a vertical mold clamping device equipped with a mold clamping cylinder that presses between the upper mold and the lower mold to clamp the movable platen in a state parallel to the fixed platen side. In the leveling control device of the vertical mold clamping device for leveling adjustment,
A plurality of leveling adjustment rods mounted on the movable platen so as to be movable along the ascending / descending direction of the movable platen, and a ball screw type for vertically moving each leveling adjustment rod along the ascending / descending direction of the movable platen. A feed mechanism section, a plurality of rod receiving sections that are respectively arranged on the fixed platen side so as to be spaced apart and opposed to the respective leveling adjusting rods, and that contact the respective leveling adjusting rods, and the respective levelings that contact the respective rod receiving sections. The pressure detecting means for detecting the contact pressure of each adjusting rod, and the operation of the feeding mechanism section are controlled based on the detection signals from the pressure detecting means, and the movable platen is pressed against the fixed platen side in advance. With the die in contact with the lower die, the leveling adjustment rods are attached to the corresponding rod receivers. After adjusting the 0-point by contacting with each other, the movable platen is moved to a position where the upper die is separated from the lower die, and the leveling adjustment rods are respectively directed toward the rod receiving portions. The same amount is fed out, and in this state, when performing the mold clamping operation of pressing the movable platen toward the fixed platen side by the mold clamping cylinder, before the upper mold contacts the lower mold, the respective leveling adjustment rods are moved. A control means for performing leveling adjustment between the movable platen and the fixed platen side by bringing the rod receiving portion side into contact with each of the leveling adjusting rods and the rod receiving portion. A characteristic leveling control device for vertical mold clamping devices. 2. A movable platen moving step for zero-point adjustment in which a movable platen holding an upper die of an injection molding die is pressed against a fixed platen holding a lower die in advance to bring the upper die into contact with the lower die. And the leveling adjustment rods of a plurality of ball screw type feed mechanism parts mounted so as to be movable along the moving up and down direction of the movable platen are brought into contact with the plurality of rod receiving parts on the fixed platen side to perform zero point adjustment. At the 0-point adjusting step and at the moving position where the movable platen is moved to the position where the upper die is separated from the lower die after the 0-point adjustment, the leveling adjustment rods are respectively directed toward the rod receiving portions. Leveling adjustment preparation process to send the same amount,
When performing the mold clamping operation of pressing the movable platen toward the fixed platen side by the mold clamping cylinder, each leveling adjustment rod is pressed by the pressing force from the mold clamping cylinder before the upper mold contacts the lower mold. Leveling adjustment step of performing leveling adjustment between the movable platen side and the fixed platen side by bringing all of them into contact with the rod receiving portion side, and a leveling control method for a vertical mold clamping device. .