JPH09234773A - Clamping device of injection molding machine and the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To render the mechanism simple, and facilitate the removal work of a molded item. SOLUTION: The clamping process is carried out by rotating nut members 9 in a normal direction via a transmission mechanism 14 by making a brake 26 on and a brake 25 off and rotating a driving shaft 21 in a normal direction by means of a driving source 21. Also, the clamping process is conducted by rotating the nut members 9 in a normal direction by making the brake 25 on and brake 26 off and rotating a driving shaft 22 in a counter direction by means of a driving source 24. After obtaining a desired clamping forces, a clamping state is kept by making the brake 26 on and stopping the driving source 24. The mold releasing process is effected by rotating the nut members 9 in a counter direction by making the brake 26 off and rotating the driving shaft 22 in a normal direction by the driving source 24 in a state described above. In addition, the mold opening process is executed by rotating the driving source 23 in a counter direction in a state of the clamping process.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mold clamping device applied to an injection molding machine, die casting, 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. 4 has been proposed (JP-A-7-8088).
No. 6). In this electric mold clamping device, two ball screws 61 with small leads are placed diagonally on the fixed plate 2 on the base 1, and two ball screws 62 with large leads are placed diagonally on the movable platen 3. The ball screws 61 and 62 are axially supported, and screw holes 64a and 64b at both ends of the ball nut 64 attached to the rotation stopping member 63 are screwed into the ball screws 61 and 62, and the ball screws 61 and 62 are respectively driven by electric motors 65 and 6.
6 is connected via transmission mechanisms 67 and 68.

The detent member 63 is movably attached to two tie bars (not shown) arranged at other diagonal positions of the fixed platen 2 and the movable platen 3, and the ball screw 6
The ball nut 64 is prevented from rotating due to the rotation of 1, 62. Each electric motor 65, 66 has a brake 69, 70 for stopping the free rotation of the ball screw 61, 62. Code 4
And 5 are molds.

The mold clamping device having the above-mentioned structure firstly
The ball screw 62 having a large lead is rotated by the electric motor 66 to move the movable platen 3 to the fixed platen 2 at a high speed, and then the electric motor 66 is stopped and the brake 70 is applied, and then the ball screw 61 having a small lead is rotated by the electric motor 65. The movable platen 3 is rotated and moved with a strong force, and the molds 4 and 6 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 screw mechanism for moving the movable platen 3 has two ball screws 61 and 62 having different leads and screw nuts 64a and 64b which match the leads of the ball screws 61 and 62. Since it consists of 64,
The structure becomes complicated. (2) Since the detent member 63 and the tie bar that stop the rotation of the ball nut 64 accompanying the rotation of the ball screws 61 and 62 are indispensable, the structure is also complicated in this respect. (3) The detent member 63 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 mold clamping device such as an injection molding machine according to claim 1 is an injection molding machine that moves a movable platen relative to a fixed platen to clamp a mold between the fixed platen and the movable platen. In a mold clamping device such as the above, a plurality of screw mechanisms in which a nut member is screwed into a screw rod are provided in parallel between the fixed plate and the movable plate, and one of the screw rod and the nut member is differentially engaged. The differential gear mechanism is connected to the first drive shaft and the second drive shaft of the differential gear mechanism, and one of the screw rod and the nut member connected to the differential gear mechanism is connected to the other. A drive source capable of forward and reverse rotation for rotating the movable plate via the is connected, and a brake is individually attached to the first drive shaft and the second drive shaft of the differential gear mechanism. .

A single drive source may be used, and a clutch may be provided on at least one of the first drive shaft and the second drive shaft. Alternatively, two drive sources may be provided and both drive shafts may be provided individually. It is also possible to have a contacted structure.

The screw rod is preferably a ball screw, the nut member is preferably a ball nut, and the drive source is preferably an electric motor such as a servo motor.

[0010]

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.

The fixed platen 2 and the movable platen 3 are both quadrangular, and screw mechanisms 7 are provided at four diagonal positions in parallel and horizontally. 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 screw rod 8 is inserted into the through hole 2a of the fixed platen 2, the flange 8a is fixed by the fixing tool 10, and the free rotation in the circumferential direction is stopped by the rotation stopper 12 so that the fixed platen 2 is fixed. Is attached to. Also, the nut member 9
Is screwed into a free end of a screw rod 8 inserted through the through hole 3a of the movable plate 3, and the flange 9a is rotatably supported by a bearing 11 and attached to the movable plate 3 so as to be rotatable in the circumferential direction. . The flange 8a and the rotation stopper 12 stop the axial movement of the screw rod 8, and the flange 9a stops the movement of the nut member 9 in the axial direction.

A differential gear mechanism 15 is connected to the nut member 9 via a transmission mechanism 14. The transmission mechanism 14 is the pulley 1 attached to the output shaft 16 of the differential gear mechanism 15.
7, a pulley 18 attached to the nut member 9, and a chain 19 wound around the pulley 17 and the pulleys 18 of all the nut members 9, but a gear or a timing belt may be used.

The differential gear mechanism 15 includes two drive shafts 21 and 22 in addition to the output shaft 16, and each drive shaft 21 and 22 includes:
A low torque / high speed rotation drive source 23 and a high torque / low speed rotation drive source 24 are individually connected. The drive sources 23 and 24 can rotate in the forward and reverse directions and have brakes (lock mechanisms) 25 and 26 such as electromagnetic brakes. The differential gear mechanism 15 and the drive sources 23 and 24 are provided on the movable platen 3.

FIG. 2 shows an example of the bevel gear type differential gear mechanism 15. To explain this, the output shaft 1
6 and the drive shaft 22 are linearly arranged with bevel gears 28 and 29 facing each other. A bevel gear 30 is rotatably fitted to the output shaft 16, and a casing 31 is rotatably fitted to the drive shaft 22. Bevel gear 30
The casing 31 and the casing 31 are integrally fixed by a bolt 32.

A plurality of bevel gears 33 are axially supported by the casing 31 and meshed with the bevel gears 28 and 29. A bevel gear 34 is attached to the drive shaft 21, and the bevel gear 30
Are engaged.

The above-mentioned differential gear mechanism 15 is well known, and the bevel gears 28 and 29 have the same number of teeth, and the bevel gear 3 has the same number of teeth.
When the number of teeth of 0, 34 is the same, it is known that the number of revolutions Na, Nb, Nc of the shafts 16, 21, 22 per unit time has the relationship of the following equation (1). Na + Nc = 2Nb (1) As can be seen from the above formula (1), the output shaft 16 rotates in the direction of arrow A (positive direction) when the drive shaft 21 rotates in the direction of arrow B (positive direction) in FIG. In addition, in FIG. 2, the output shaft 16 rotates in the direction of arrow A (forward direction) when the drive shaft 22 rotates in the direction of arrow C (reverse direction).

The brake 25 blocks the free rotation of the bevel gear 30 when the drive source 24 operates independently, and the other brake 26 blocks the free rotation of the bevel gear 29 when the drive source 23 rotates independently. Is.

By the way, in the injection molding machine, each step 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 such as the injection molding machine of the above embodiment, for example, the drive source 24 is rotated in the single reverse direction (see FIG. 2).
The rotation of the nut member 9 in the positive direction (the rotation direction in which the movable platen 3 approaches the fixed platen 2) is performed in the mold clamping process, and the mold release process is performed in the positive direction rotation. Single forward rotation of the source 23 (rotation in the direction of arrow B in FIG. 2)
Then, the nut member 9 is rotated in the forward direction to perform the mold closing process, and the reverse rotation is performed to perform the mold opening process.

That is, in the mold closing process, the brake 26 is turned on, the brake 25 is turned off, and the drive source 23 drives the drive shaft 2
By rotating 1 in the forward direction, the nut member 9 is rotated in the forward direction via the transmission mechanism 14. If the rotation speed Nb of the drive shaft 21 by the drive source 23 is 1000 rp
When m is set, as is clear from the equation (1), the output shaft 16 rotates in the positive direction at 2000 rpm and the nut member 9 rotates in the positive direction at a high speed, so that the movable platen 3 is fixed at a high speed. Close to board 2.

In the next mold clamping step, the brake 25 is turned on,
The brake 26 is turned off, and the drive shaft 24 is rotated in the reverse direction by the drive source 24 to rotate the nut member 9 in the forward direction. If the rotation speed Nc of the drive shaft 22 driven by the drive source 24 is 100 rpm, the output shaft 16 is 1
Since the nut member 9 is rotated in the forward direction at 00 rpm to rotate the nut member 9 in the forward direction at a low speed, the movable platen 3 is moved at a low speed at the fixed platen 2.
And close the molds 4 and 5 with high pressure. After the required mold clamping force is reached, the brake 26 is turned on and the drive source 24 is stopped to maintain the mold clamping state.

The mold releasing step is performed by turning off the brake 26 in the above state and rotating the drive shaft 22 in the forward direction by the drive source 24 to rotate the nut member 9 in the reverse direction. In this case, the movable platen 3 separates from the fixed platen 2 at low speed and high pressure.

In the case of the mold opening process, the brake 26 is turned on, the brake 25 is turned off, and the drive source 23 drives the drive shaft 21.
By rotating the nut member 9 in the opposite direction. In this case, it goes without saying that the movable platen 3 separates from the fixed platen 2 at a high speed.

Both drive sources 2 are used for the mold closing process and the mold opening process.
It is also possible to carry out simultaneous operation of 3,24. In this case, the drive shafts 21 and 22 are set in the forward direction at 1000 rpm and 100 rp.
When rotated at m, the output shaft 16 moves in the positive direction at 1900 rp
It rotates at a speed of m and drives the drive shaft 21 in the positive direction at 1000 rp.
When the other drive shaft 22 is rotated in the reverse direction at 100 rpm, the output shaft 16 is rotated in the forward direction at 2100 rpm. In addition, the drive shafts 21 and 22 are set to 100 in the opposite direction.
When rotated at 0 rpm and 100 rpm, the output shaft 16 rotates in the reverse direction at 1900 rpm, the drive shaft 21 in the reverse direction at 1000 rpm, and the other drive shafts 22 in the forward direction at 100 r.
When rotated at pm, the output shaft 16 moves 2100r in the opposite direction.
Rotate at pm.

The drive source 23 may be of high torque / low speed rotation, and the other drive source 24 may be of low torque / high speed rotation. The nut member 9 may be fixed and the screw rod 8 may be rotated. 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. The differential gear mechanism 15 and the drive sources 23 and 24 are screw mechanisms 7.
Is provided on the rotation side of.

The drive sources 23 and 24 are preferably variable speed ones rather than constant speed ones. Ordinary electric motors and hydraulic motors can be used for the drive sources 23 and 24,
It is desirable to use servomotors as the drive sources 23 and 24, because it is easy to control the position of the movable platen 3 and to easily control the operation of the mold clamping device with high accuracy. Both drive sources 2
It is most desirable to use servo motors for both 3 and 24,
Only one of them may be the servo motor. The types of both drive sources 23 and 24 may be the same or different.

The structure and type of the differential gear mechanism 15 are not limited to those shown in FIG. 2 and may be arbitrary. Also, axis 2
Alternatively, one of the output shafts 1 and 22 may be used as an output shaft to communicate with the screw mechanism 7 via the transmission mechanism 14, and the shaft 16 may be used as a drive shaft to communicate with a drive source.

FIG. 3 shows another embodiment of the present invention. In addition,
The same members and the like as those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted. Drive shaft 2 of differential gear mechanism 15
1, a connecting shaft 41 having a bevel gear 40 is connected to a brake 42 such as an electromagnetic brake via a clutch 43 such as an electromagnetic clutch, and the other drive shaft 22 includes a connecting shaft 45 having a spur gear 44. A brake 46 such as an electromagnetic brake is connected to a clutch 47 such as an electromagnetic clutch.

The bevel gear 40 and the spur gear 44 have bevel gears 5 of a rotating shaft 50 rotated by a drive source 49.
1 and the spur gear 52 are individually meshed with each other.
Bevel gears 40 and 51 constitute a speed increasing mechanism, and spur gears 44 and 5
Reference numeral 2 constitutes a speed reduction mechanism. The bevel gears 40, 51
Can be a deceleration or constant velocity mechanism, and the spur gears 44, 52 can be a constant velocity or deceleration mechanism.

In the mold clamping device of the injection molding machine of FIG. 3, for example, the brake 46 and the clutch 43 are turned on, the clutch 47 and the brake 42 are turned off, and the drive source 49 rotates the drive shaft 21 in the forward direction. By doing so, the nut member 9 is rotated at high speed with low torque to perform the mold closing step. Further, in the above state, the drive shaft 21 is driven by the drive source 49.
Then, the mold is opened by rotating it in the opposite direction.

In the mold clamping process, the brake 42 and the clutch 47 are turned on, the clutch 43 and the brake 46 are turned off, and the drive shaft 22 is rotated in the reverse direction by the drive source 49, whereby the nut member 9 is rotated. Rotate in the forward direction with high torque and low speed. After the required mold clamping force is reached, the brake 46 is turned on and the drive source 49 is stopped to keep the mold clamping state. Further, in the above state, the brake 46 is turned off and the drive shaft 22 is rotated in the forward direction by the drive source 49 to perform the releasing process.

Also in the mold clamping device of the injection molding machine of FIG. 3, the types of the drive source 49 and the transmission mechanism 14 are as described above.
The present invention is not limited to the one shown in the figure, and various design changes are possible.

The bevel gears 40 and 51 and the spur gears 44 and 5 are also provided.
A speed increasing mechanism or a speed reducing mechanism other than 2 can be used. Providing a required rotation direction conversion mechanism between the drive source 49 and the drive shaft 21, and between the drive source 49 and the drive shaft 22, or any one of them, converts the rotation directions of the drive shafts 21 and 22 arbitrarily. Thus, the moving speed of the movable platen 3 can be widely changed.

Although the mold clamping devices such as the injection molding machines shown in FIGS. 1 and 3 are both horizontal, the present invention can be applied to a vertical injection molding machine.

[0036]

As described above, in the mold clamping device of the injection molding machine according to the first aspect, the movable platen is moved with respect to the fixed platen to clamp the mold between the fixed platen and the movable platen. In a mold clamping device such as an injection molding machine, a plurality of screw mechanisms in which a nut member is screwed into a screw rod are provided in parallel between the fixed plate and the movable plate, and any one of the screw rod and the nut member is provided. The differential gear mechanism is connected to one of them, and one of the screw rod and the nut member connected to the differential gear mechanism is connected to the other of the first drive shaft and the second drive shaft of the differential gear mechanism. Is connected to a drive source capable of forward and reverse rotation for rotating the movable platen via a differential gear mechanism, and brakes are individually provided to the first drive shaft and the second drive shaft of the differential gear mechanism. Since it is configured to be attached to the 2 types of screws, 2 types of screws with different leads Also, since a nut member is not required and only one type of screw rod and nut member is required, and further, it is not necessary to provide a rotation stopping member for the nut member between the fixed platen and the movable platen, the structure of the device is simplified and the cost is reduced. In addition, there is an advantage that it does not hinder the taking out of the molded product and the work of exchanging the mold is easy.

If only one drive source is used, the cost can be further reduced. If the number of drive sources is two, control becomes easy. If the screw rod is a ball screw and the nut member is a ball nut, the operation will be smooth,
Power is saved and accuracy is improved.

When the drive source 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 sectional view showing an example of a differential gear mechanism.

FIG. 3 is a sectional view showing another embodiment of a mold clamping device such as an injection molding machine according to the present invention.

FIG. 4 is a sectional view of a mold clamping device of a conventional injection molding machine.

[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) 14 Transmission mechanism 15 Differential gear mechanism 21, 22 Drive shaft 23, 24, 49 Drive source 25, 26, 42, 46 Brake 43, 47 Clutch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // B29K 21:00

Claims (6)

[Claims] 1. 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 onto a screw rod are provided in parallel with each other, and the differential gear mechanism is connected to either one of the screw rod and the nut member, and Forward and reverse in which the movable platen is moved by rotating one of the screw rod and the nut member connected to the differential gear mechanism with respect to the other through the differential gear mechanism on the first drive shaft and the second drive shaft. A mold clamping device for an injection molding machine or the like, wherein a rotatable drive source is connected, and brakes are individually attached to the first drive shaft and the second drive shaft of the differential gear mechanism. 2. A single drive source, a first drive shaft and a second drive shaft.
The mold clamping device for an injection molding machine or the like according to claim 1, wherein a clutch is provided on at least one of the drive shafts. 3. A mold clamping device for an injection molding machine or the like according to claim 1, wherein there are two drive sources, and the two drive shafts are individually connected to each other. 4. The mold clamping device of an injection molding machine or the like according to claim 1, wherein the screw rod is a ball screw and the nut member is a ball nut. 5. The mold clamping device for an injection molding machine according to claim 1, 2, 3 or 4, wherein the drive source is an electric motor. 6. The mold clamping device for an injection molding machine or the like according to claim 5, wherein the electric motor is a servo motor.