JPH09225980A - Method and apparatus for clamping injection molding machine and others - Google Patents

Abstract

PROBLEM TO BE SOLVED: To render the mechanism simple and facilitate the removal of molded items. SOLUTION: The closing process is carried out in such a manner that both brakes 15, 21 are turned off, and a screw rod 8 is rotated in the positive direction by a rotation driving device 13, and further a nut member 9 is rotated in the positive direction (counter direction of the screw rod 8) by a rotation driving device 14. The clamping process is such that a brake 21 is made on, and the screw rod 8 is rotated in the positive direction by a high torque electric motor 16 of the rotation driving device 13. After clamping forces reach desired one, the brake 15 is turned on, thereby maintaining the clamping condition. Also, the releasing process is executed by making the brake 15 off and rotating the screw rod 8 in the counter direction by the electric motor 16. The opening process is that both the brakes 15, 21 are made off, and the rod 8 is rotated in the counter direction by the rotation driving device 13, and then the nut member 9 is rotated in the counter direction by the rotation driving device 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping method and a mold clamping device applied to an injection molding machine, a die cast, a rubber vulcanizing press or the like.

[0002]

2. Description of the Related Art As an electric mold clamping device for an injection molding machine,
The one shown in FIG. 5 has been proposed (JP-A-7-8088).
No. 6). In this electric mold clamping device, two ball screws 41 with small leads are diagonally positioned on the fixed plate 2 on the base 1, and two ball screws 42 with large leads are diagonally positioned on the movable platen 3. The screw holes 44a and 44b at both ends of the ball nut 44 attached to the rotation stopping member 43 are screwed to the ball screws 41 and 42, respectively, and the motors 45 and 4 are respectively attached to the ball screws 41 and 42.
6 is connected via transmission mechanisms 47 and 48.

The detent member 43 is movably attached to two tie bars (not shown) arranged at other diagonal positions of the fixed plate 2 and the movable plate 3, and the ball screw 4
The ball nut 44 is prevented from rotating due to the rotation of 1, 42. Each electric motor 45, 46 has a brake 49, 50 for stopping the free rotation of the ball screw 41, 42. Code 4
And 5 are molds.

The mold clamping device having the above-mentioned structure firstly
The ball screw 42 having a large lead is rotated by the electric motor 46 to move the movable platen 3 to the fixed platen 2 at a high speed, and then the electric motor 46 is stopped to apply the brake 50. The movable platen 3 is rotated and moved with a strong force, and the molds 4 and 5 are clamped between the fixed platen 2 and the movable platen 3.

[0005]

SUMMARY OF THE INVENTION The above mold clamping device is
Since the end plate fixed to one end of the tie bar and the toggle mechanism are unnecessary, it has an advantage that the length of the mold clamping device can be shortened, but it has the following problems.

(1) A ball nut having a screw mechanism for moving the movable platen 3 has two ball screws 41 and 42 having different leads and screw holes 44a and 44b corresponding to the leads of the ball screws 41 and 42. Because it consists of 44,
The structure becomes complicated. (2) Since the detent member 43 for stopping the rotation of the ball nut 44 accompanying the rotation of the ball screws 41 and 42 and the tie bar are indispensable, the structure is also complicated in this respect. (3) The detent member 43 interferes with the removal of the molded product and the replacement of the mold, which makes the work difficult.

[0007]

At least one of the above-mentioned problems
In order to solve the above problem, a method of clamping a mold such as an injection molding machine according to claim 1 is such that a screw rod and a nut member of a screw mechanism provided between a fixed platen and a movable platen are different from each other by a rotary drive device. In the same direction to move the movable platen closer to the fixed platen, then stop either one of the screw rod and the nut member to apply the brake, and rotate the screw rod and the nut member to rotate the fixed platen and the movable platen. The mold is clamped between the two.

The screw rod and the nut member can be rotated by a single drive source. The screw rod and the nut member are simultaneously rotated in mutually different directions by the rotary drive unit having a small torque and the rotary drive unit having a large torque, which are respectively connected to the screw rod and the nut member, to move the movable platen closer to the fixed platen, and then the torque. It is also possible to stop the rotation drive device having a small torque and apply a brake, and perform mold clamping by rotation of the rotation drive device having a large torque.

A mold clamping device such as an injection molding machine according to a fourth aspect is an injection molding machine or the like that moves a movable platen with respect to a fixed platen to clamp a mold between the fixed platen and the movable platen. In the mold clamping device, a plurality of screw mechanisms in which a nut member is screwed into a screw rod are provided in parallel with each other between the fixed plate and the movable plate, and the screw rod is rotated with respect to the nut member. And a second rotary drive device capable of forward and reverse rotation for rotating the nut member with respect to the threaded rod to the nut member. The first rotary drive device and the second rotary drive device are individually provided with brakes.

It is preferable that the screw rod is a ball screw, the nut member is a ball nut, and the drive source of the rotary drive device is a servo motor.

It is also possible to share the drive source of the rotary drive device for the screw rod and the rotary drive device for the nut member, and to provide a clutch on at least one of the rotary drive devices.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described based on examples with reference to the drawings. In FIG. 1, reference numeral 1 is a base, and a fixed platen 2 and a movable platen 3 are provided on the base 1 in parallel and perpendicular to each other. The fixed platen 2 is fixed to the base 1, and the movable platen 3 is movable on the base 1 in the direction of alignment with the fixed platen 2 (left and right direction in FIG. 1). Fixed board 2
Molds 4 and 5 are attached to the movable platen 3.

As shown in FIGS. 2 and 3, the fixed platen 2 and the movable platen 3 are both quadrangular, and screw mechanisms 7 are provided in parallel and horizontally at diagonal positions thereof. The screw mechanism 7 includes a screw rod 8 and a nut member 9 screwed to the screw rod 8. Usually, the screw rod 8 is a ball screw, and the nut member 9 is a ball nut.

One end of the threaded rod 8 is inserted into the through hole 2a of the fixed platen 2, and the portion of the flange 8a is supported by the bearing 10.
It is rotatably supported by and fixed to the fixed platen 2 so as to be rotatable in the circumferential direction. Further, the nut member 9 has a through hole 3 a in the movable platen 3.
Is screwed into the free end of the screw rod 8 inserted in the
The portion a is rotatably supported by the bearing 11 and is rotatably attached to the movable platen 3 in the circumferential direction. The flanges 8a and 9a stop the axial movement of the screw rod 8 and the nut member 9.

The screw rod 8 and the nut member 9 are individually connected to rotary drive devices 13 and 14, respectively. The rotation drive device 13 rotates the screw rod 8 with respect to the nut member 9, and uses a high torque / low speed rotation electric motor 16 equipped with a brake (lock mechanism) 15 and capable of normal and reverse rotation as a drive source. Pulley 17, chain 18, pulley 1
It is adapted to be transmitted to the threaded rod 8 via 9. The other rotary drive device 14 is for rotating the nut member 9 with respect to the threaded rod 8, and has a low torque / high speed rotation electric motor 22 equipped with a brake 21 capable of forward and reverse rotation as a drive source. Pulley 23, chain 24, pulley 25
It is configured to be transmitted to the nut member 9 via.

The brake 15 blocks the free rotation of the screw rod 8 when the nut member 9 is independently rotated by the rotary drive device 14, and the other brake 21 is the independent rotation of the screw rod 8 by the rotary drive device 13. It sometimes prevents the nut member 9 from freely rotating. Electromagnetic brakes are usually used for the brakes 15 and 21.

In the injection molding machine, each process of the mold clamping device is generally performed as follows. 1) Mold closing step This is a step from the mold opening position to the mold clamping start position, in which the movable platen 3 is moved at low pressure and high speed. 2) Mold clamping process This is a process from the mold clamping start position just before the molds 4 and 5 are fitted to the required mold clamping force, in which the movable platen 3 is moved at high pressure and low speed. 3) Mold release process The movable platen 3 is moved at high pressure and low speed in the process from the mold clamping state until the molds 4 and 5 are slightly opened. 4) Mold Opening Step This is the step from the mold releasing completion position to the mold opening position, in which the movable platen 3 is moved at low pressure and high speed.

In the mold clamping device of the above embodiment, the mold clamping process is usually reversed by the rotation drive device 13 independently rotating the screw rod 8 in the normal direction (the rotation direction in which the movable platen 3 moves to the right in FIG. 1). The mold releasing process is performed by the directional rotation, the mold closing process is performed by the forward rotation of the screw rod 8 and the nut member 9 by the rotation driving devices 13 and 14, and the mold opening process is performed by the reverse rotation.

That is, in the mold closing process, both brakes 1
5, 21 are turned off, the screw rod 8 is rotated in the forward direction by the rotation drive device 13, and the nut member 9 is rotated in the forward direction (direction opposite to the screw rod 8) by the rotation drive device 14. In this case, the movable platen 3 moves at a high speed that is the sum of the feed speeds of the screw rod 8 and the nut member 9.

In the next mold clamping step, the brake 21 is turned on, the nut member 9 is fixed, and the screw rod 8 is rotated in the forward direction by the high torque electric motor 16 of the rotary drive device 13. After the required mold clamping force is reached, the brake 15 is turned on and the electric motor 16 is stopped to maintain the mold clamping state. The mold releasing step is performed by turning off the brake 15 and rotating the screw rod 8 in the reverse direction by the electric motor 16 as described above. In the mold clamping process and the mold releasing process, the movable platen 3 moves at low speed and high pressure.

In the mold opening step, both brakes 15 and 21 are turned off, the screw rod 8 is rotated in the reverse direction by the rotary driving device 13, and the nut member 9 is rotated by the rotary driving device 14 as in the mold closing step. Reverse direction (direction opposite to the screw rod 8)
Rotate to. In this case, the movable platen 3 moves at a high speed which is the sum of the feed speeds of the screw rod 8 and the nut member 9 as in the mold closing step.

The brake 15 is used for the mold closing process and the mold opening process.
Alternatively, the screw rod 8 may be fixed by turning on, and the nut member 9 may be rotated in the forward and reverse directions by the high-speed rotating electric motor 22 of the rotary drive device 14. Depending on the injection molding machine or the like, the mold opening step may be performed without the release step.

In addition to the above, the electric motor 16 may be of low torque / high speed rotation, and the other motor 22 may be of high torque / low speed rotation. At this time, it goes without saying that the mold clamping process and the mold releasing process are performed by the electric motor 22. Alternatively, the fixed plate 2 may be provided with the nut member 9 and the movable plate 3 may be provided with the screw rod 8. Chain 18,
With the transmission mechanism mainly composed of 24, the rotational speed and torque of the screw rod 8 and the nut member 9 can be adapted to each process. Further, the transmission mechanism may be provided with a speed reducer or a speed increaser so that the rotational speed and torque of the screw rod 8 and the nut member 9 can be set to predetermined values.

It is preferable that the electric motors 16 and 22 have variable speeds rather than constant speeds. When the electric motors 16 and 22 are servomotors, the position control of the movable platen 3 is facilitated, and the operation control of the mold clamping device is facilitated with high accuracy, which is desirable. It is most preferable that both electric motors 16 and 22 are servo motors, but only one of them may be a servo motor. As the drive source of the rotary drive devices 13 and 14, other than the electric motor, rotary drive means such as a hydraulic motor can be used in the same type or in different types.

The transmission mechanism for transmitting the rotation of the driving sources 16 and 22 to the screw rod 8 and the nut member 9 includes chains 18 and 2 shown in the figure.
4. In addition to the pulleys 17, 23, 19 and 25, any transmission mechanism using a timing belt, gears or the like can be used. The brakes 15 and 21 may be provided in the transmission mechanism, or may be provided in the bearings 10, 11 and the like.

FIG. 4 shows another embodiment of the present invention. In addition,
The same members and the like as those in FIGS. 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted. Reference numeral 30 is an electric motor capable of forward and reverse rotations, and is shared by the rotary drive devices 13 and 14 as a drive source. The electric motor 30 is configured such that the bevel gear 31 meshes with the bevel gears 34 and 35 of the rotary shafts 32 and 33 to form the base 1
Alternatively, it is fixed to the fixed platen 2.

The pulley 17 is attached to the rotary shaft 32,
The other pulley 23 is attached to the rotating shaft 33 via a clutch (electromagnetic clutch) 36. A brake 37 that locks the nut member 9 is provided between the pulley 23 and the movable platen 3. The transmission mechanism of the rotary drive device 13 is configured to rotate the screw rod 8 at high torque and low speed, and the transmission mechanism of the rotary drive device 14 is configured to rotate the nut member 9 at low torque and high speed. 38 is a brake.

In the mold clamping device such as the injection molding machine shown in FIG. 4, the screw rod 8 and the nut member 9 are rotated by rotating the electric motor 30 in the forward direction with the clutch 36 turned on and the brake 37 turned off. Are simultaneously rotated in different directions to perform a mold closing step. In addition, the mold opening step is performed by rotating the electric motor 30 in the opposite direction in the above state.

In the mold clamping step, the clutch 36 is turned off, the brake 37 is turned on, and the electric motor 30 is rotated in the forward direction. After the required mold clamping force is reached, the brake 38 is turned on and the electric motor 30 is stopped to maintain the mold clamping state. The releasing step is performed by turning off the brake 38 while keeping the clutch 36 off and the brake 37 on and rotating the electric motor 30 in the reverse direction.

Also in the mold clamping device of FIG. 4, the driving source 30
The type of the transmission mechanism and the transmission mechanism are not limited to those shown in the figures, and various design changes can be made as described above. 1 and 4 are both horizontal types, the present invention can also be applied to a vertical injection molding machine or the like.

[0031]

As described above, the mold clamping method of the injection molding machine or the like according to claims 1 and 3 and the mold clamping device of the injection molding machine or the like according to claim 4 are configured as described above. Since two types of screw rods and nut members with different leads are not necessary, only one type of screw rod and nut member is required, and there is no need to provide a rotation stopping member for the nut member between the fixed platen and the movable platen. It has the advantages that the structure of the device can be simplified and the cost can be reduced, that there is no hindrance to the removal of the molded product, and that the work of exchanging the mold is easy.

A drive source is shared between the rotary drive device for the screw rod and the rotary drive device for the nut member, and a clutch is provided on at least one of the rotary drive devices to provide a drive source for the screw rod and the nut member. When the structure is rotated by, the layer cost can be further reduced. If the screw rod is a ball screw and the nut member is a ball nut, the operation becomes smooth, the power is saved, and the accuracy is improved.

When the drive source of the rotary drive device is an electric motor, the structure is simpler and the power loss is smaller than when the drive source is a hydraulic motor. When the electric motor is a servo motor, the operation control of the mold clamping device can be highly accurate.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a mold clamping device such as an injection molding machine according to the present invention.

FIG. 2 is a (II-II) arrow view of FIG.

FIG. 3 is a view on arrow (III-III) in FIG. 1.

FIG. 4 is a diagram of a main part showing another embodiment of the mold clamping device according to the present invention.

FIG. 5 is a cross-sectional view of a conventional mold clamping device.

[Explanation of symbols]

 2 Fixed plate 3 Movable plate 4, 5 Mold 7 Screw mechanism 8 Screw rod (ball screw) 9 Nut member (ball nut) 13, 14 Rotation drive device 15, 21 Brake 16, 22, 30 Electric motor (servo motor) 37 Brake

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29K 105: 24

Claims (8)

[Claims] 1. A movable plate is moved closer to a fixed plate by simultaneously rotating a screw rod and a nut member of a screw mechanism provided between the fixed plate and the movable plate in different directions by a rotary drive device. An injection molding machine characterized in that either one of a screw rod and a nut member is stopped to apply a brake, and the rotation of the other of the screw rod and the nut member clamps a mold between a fixed platen and a movable platen. Clamping method such as. 2. The mold clamping method for an injection molding machine or the like according to claim 1, wherein the screw rod and the nut member are rotated by a single drive source. 3. The movable plate approaches the fixed plate by simultaneously rotating the screw rod and the nut member in mutually different directions by a low torque rotary drive unit and a high torque rotary drive unit respectively connected to them. After moving, stop the rotation drive device with small torque and apply the brake,
The mold clamping method for an injection molding machine or the like according to claim 1, wherein the mold clamping is performed by rotation of a rotary drive device having a large torque. 4. A mold clamping device, such as an injection molding machine, which moves a movable platen with respect to a fixed platen to clamp a mold between the fixed platen and the movable platen. A plurality of screw mechanisms in which a nut member is screwed into the screw rod are provided in parallel with each other, and the screw rod has a first rotation drive capable of rotating the screw rod with respect to the nut member in the forward and reverse directions. A device is connected to the nut member, and a second rotary drive device capable of rotating the nut member with respect to a screw rod is connected to the first rotary drive device and the second rotary drive device.
A mold clamping device for an injection molding machine or the like, in which brakes are individually attached to the rotation drive device. 5. The screw rod is a ball screw, and the nut member is a ball nut.
Mold clamping device such as the described injection molding machine. 6. The mold clamping device for an injection molding machine or the like according to claim 4, wherein the drive source of the rotary drive device is an electric motor. 7. The mold clamping device for an injection molding machine according to claim 6, wherein the electric motor is a servo motor. 8. The drive source of the rotary drive device for the screw rod and the rotary drive device for the nut member are shared, and at least one of the rotary drive devices is provided with a clutch. , 5, 6 or 7, a mold clamping device such as an injection molding machine.