JPS623712B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing loosening of a column nut attached to a link housing in an injection molding apparatus such as a die casting machine or an injection molding machine.

Generally, in an injection molding machine, a fixed mold and a movable mold are butted against each other, and both are clamped with a large force to apply a predetermined mold clamping force, and molten metal is injected into the mold cavity to form the mold. is being carried out.

In such injection molding equipment, depending on the size of the mold and the type of molded product, the distance between the fixed plate and the movable plate when the mold is installed and clamped, that is, the die height, is determined by the thickness of the mold. It is necessary to adjust the mold clamping force subtly.

Normally, in die casting machines, etc., four column nuts attached to the link housing are rotated simultaneously via a single chain, etc., to move the link housing and movable platen, etc., adjust the die height, and clamp the mold. Adjusting the power.

However, in such a device, a large force is applied to the column nut portion each time the mold is clamped, each injection is performed, and the mold is opened, and the force acting on the column nut portion disappears, so that the column nut inevitably tends to loosen.

The present invention is intended to eliminate this drawback, and uses a mold clamping force adjustment device that can finely adjust the mold clamping force to prevent the column nut from loosening.

In order to achieve the above object, the present invention uses a mold clamping force adjustment device that adjusts the mold clamping force by rotating a column nut, and when adjusting the mold clamping force by rotating the column nut, the moving member of the cylinder The cylinder device, which performs pitch drive according to the resolution of the mold clamping force adjustment device determined by the moving distance of Then, in the final step of adjusting the mold clamping force, move the movable member of the cylinder to the travel limit position on the side where the column nut is about to loosen, and with the clutch connected, move the movable member at the travel limit position. The parts were held in place to prevent the column nut from loosening.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 and the following illustrate one embodiment of the present invention, 1 is a fixed plate, 2 is a movable plate, 3 is a link housing, 1a is a fixed mold, 2a is a movable mold, 3a is a column, 4, 4a is a column nut, 5 is a mold clamping cylinder, 5a is a toggle mechanism, and 6 is a machine base. By turning the column nut 4 on the link housing 3 side, the link housing 3 is moved to the column 3.
Move it along a to adjust the die height,
It is now possible to adjust the mold clamping force.

Parts of all the column nuts 4 rotatably attached to the link housing 3 are chain foil portions 4b, and between these chain foil portions 4b and a chain foil 7a fixed to the output shaft of the motor 7 attached to the link housing 3. An endless chain 8 is wound around it, and the die height can be adjusted by turning four column nuts 4 at the same time by the action of a motor 7.

A part of the chain 8 is wrapped around a chain foil 7b that serves as an idler to keep the chain 8 taut. However, since this chain foil 7b acts when adjusting the mold clamping force as described later, a dedicated idler may be provided elsewhere.

As shown in the enlarged view in Fig. 3, the chain foil 7
b is fixed to the shaft 9. An electromagnetic clutch 10 is attached to the other end of the shaft 9. The electromagnetic clutch 10 is a non-excited clutch, and is structured so that the clutch is engaged when the power is turned off and disengaged when the power is turned on. Please note that this clutch is a non-excitation operated type, so
During normal mold closing or injection operation, it also functions to prevent the chain foil 7b from rotating, and therefore also functions to prevent the chain 8 and column nut 4 from loosening. Conventionally, during long-term use of a device such as a die-casting machine, the column nut 4 sometimes loosened due to repeated loads and a predetermined mold clamping force could not be obtained, but this can be prevented.

The shaft 9 is connected to the casing 11 via a bearing 9a.
A pinion 12 is rotatably supported within the casing 11 via a bearing 13. The inner peripheral surface of the pinion 12 is rotatably supported on the small diameter portion of the shaft 9 via a bearing 13a. The casing 11 is attached to a part of the link housing 3 with bolts. 11a is a window through which the chain 8 wound around the chain foil 7b passes.

One end of the electromagnetic clutch 10 is fixed to one end of the pinion 12. Therefore, the electromagnetic clutch 10 is installed between the shaft 9 and the pinion 12.

As shown in FIG.
Cylinder cases 15, 15 provided in a part of 1
It meshes with a rack gear 17 formed in the center of a rod 16 suspended horizontally between them.

Both ends of the rod 16 are attached to the cylinder case 15.
The cylinder case 1 has a ram part 18 that is slidably fitted in a sealed state within the cylinder case 1.
Hydraulic oil is supplied to 5 from flow ports 15a and 15b, respectively. In the state shown in FIG.
The distance S between the tip of the cylinder case 15 and the inner wall of the cylinder case 15 is, for example, 10 mm.
The operating pitch of 8 and the resolution of this fine adjustment device are determined.

Further, a projecting piece 19 is provided on the rod 16, and this projecting piece 19 faces the outside of the casing 15, and is located at a position where it can come into contact with the limit switches _L1 and _L2, respectively.

In addition, this device is equipped with a device that, when the adjusted mold clamping force falls within the permissible range, positions the ram portion 18 at a movement limit position on the side where the column nut 4 is about to loosen, that is, on the side where it will not loosen any further. A control device is provided to cut off the power to the electromagnetic clutch 10.

Next, the operation of this embodiment configured as above will be explained.

First, when adjusting the die height, the electromagnetic clutch 10 between the shaft 9 and the pinion 12 is turned off, the motor 7 is rotated, and the chain 8 rotates all the column nuts 4. Then, the link housing 3 and the like move, and a predetermined die height is obtained. During this operation, the electromagnetic clutch 10
Since the pinion 12 is blocked, the pinion 12 does not rotate and therefore the rod 16 also remains stationary.

Next, when adjusting the mold clamping force, the power to the electromagnetic clutch 10 is turned off and the electromagnetic clutch 10 is activated so that the shaft 9 and pinion 12 rotate together. Then, in order to finely adjust the clamping force, press the switch that increases or decreases the clamping force to move the shaft 7 in the desired direction while the molds 1a and 2a are not in contact with each other. Cylinder case 15 on the side that moves the rod 16 in the direction of rotation
Hydraulic oil is supplied to the side from a hydraulic source (not shown). This supply of hydraulic oil moves the rod 16 via the ram section 18, but the limit of this movement is determined by the distance the rod 16 moves, and the tip of the ram section 18 on the opposite side hits the inner wall of the casing 15. It becomes a place. The pinion 12 rotates via the rack gear 17 according to the stroke of the rod 16, the chain wheel 7b rotates via the shaft 9, and the chain 8 rotates slightly. Chain 8 at this time
Since the amount of travel is extremely small, the amount of rotation of each column nut 4 rotated via the chain wheel portion 4b is also small, and the movement of the link housing 3, movable platen 2, and therefore movable mold 2a is also small. .

If the desired mold clamping force cannot be obtained with one fine adjustment, move the rod 16 to the opposite side with the electromagnetic clutch 10 disengaged, then engage the electromagnetic clutch 10 again, and then move the rod 16 to the opposite side. 16 in the initial direction, the rod 16 is reciprocated multiple times in this manner, and the pitch drive is repeated multiple times to make fine adjustments until the desired mold clamping force is obtained. In addition,
When one of the limit switches L ₁ and L ₂ is activated, oil supply to one cylinder 15 is stopped, and when the other is activated, oil is supplied to the opposite cylinder 15.

In addition, in FIG. 4, when the electromagnetic clutch 10 is connected and hydraulic oil is supplied to the flow port 15a and the rod 16 moves forward to the right, the column nut moves in the direction of tightening and the die height becomes smaller. , the mold clamping force is set to be large, and with the electromagnetic clutch 10 engaged, the flow port 1 is
When hydraulic oil is supplied to 5b and the rod 16 retreats to the left, the column nut moves in the direction of loosening.
The die height was increased and the mold clamping force was decreased. In addition, in FIG. 4, the rod 16
has moved to the left end, so the column nut 4 is no longer loosened.

By the way, when the mold clamping force is actually controlled using the pitch drive as described above, it is carried out manually or automatically in the following manner.

First, in the case of manual operation, how many tons of mold clamping force can be increased or decreased in one operation by the pitch drive device described above, and how many tons should the rod 16 be adjusted until the desired mold clamping force is reached by the operator. Calculate how many times it should be moved, and press the push button for driving the pitch drive device the required number of times.

In this case, there may be a slight error between the mold clamping force depending on the number of times the button is pressed and the desired mold clamping force, but if the error is within the allowable range, the ram part 18 will move in one direction. The power to the electromagnetic clutch 10 is kept turned off while the column nut 4 is located at the movement limit position on the side where the column nut 4 is about to loosen, that is, on the side where it will not loosen any further. Leave the effect as it is, and if it is not within the acceptable range, press the button again.

On the other hand, when automatically adjusting the mold clamping force, as shown in FIG. The mold clamping force is detected and the mold clamping force is calculated from this elongation in the mold clamping force calculator 21. At this time, if the desired mold clamping force is achieved, the work is completed as is, but if there is a difference between the desired mold clamping force and the desired mold clamping force that is larger than the allowable range, the average mold clamping force calculator 22 calculates For example, calculate the average value of the mold clamping force when mold clamping is performed two to three times, and compare this actual average mold clamping force with the mold clamping force set value set by the mold clamping force setting device 23 using the comparator 24. Compare them and get the difference, which is the deviation value. Reference numeral 25 denotes a setting device for setting the resolution of the mold clamping force, that is, the allowable range, and the value set here is compared with the excess or insufficient mold clamping force obtained by the comparator 24. If the deviation value is within the allowable range, the comparator 25a recognizes it as a dead zone, and if it is outside the allowable range, the control device 26 including a correction number calculator determines the number of corrections.
That is, it is determined how many pitches the drive device is to be operated. Of course, this control device 26 instructs the forward and backward movement of the link housing 3, that is,
It also instructs the moving direction of the rod 16 when the clutch 10 is engaged and disengaged, and also sends out pulse signals based on operation commands.

Then, based on the above calculation, the actuator control circuit 27, which is the power circuit of the pitch drive device, is activated via the preset down counter 27a.
The operation is continued until the desired mold clamping force is reached. At this time, signals from the limit switches L ₁ and L ₂ are also input to the actuator control circuit 27, and based on these signals, the flow port 1 of the cylinder case 15 is
Solenoids 28a and 28b of the electromagnetic switching valves that supply and cut off hydraulic oil to 5a and 15b are energized and demagnetized, and the electromagnetic clutch 10 is energized and demagnetized.

Now, suppose that the set value of the mold clamping force is 800 tons, the set value of the allowable range is 8 tons, and the mold clamping force that can be changed by one operation of an actuator such as the rod 16 is 8 tons. , when the average mold clamping force is 750 tons, the deviation value of the mold clamping force calculated by the comparator 24 is 50 tons. This value is within the acceptable range
Since it is larger than 8 tons, it is calculated by the calculator in the control device 26, and the number of corrections is 6 times. in this case,
Even if the rod 16 is reciprocated six times, the mold clamping force is still 2 tons short of the predetermined mold clamping force, but since this value is within the allowable range, it is satisfied with six corrections.

Then, in the final step of adjusting the mold clamping force, the ram part 18 is moved to one of the limits of movement, and after that, the power to the electromagnetic clutch 10 is kept turned off and the electromagnetic clutch 10 continues to act. I'll keep it. Then, hold the column nut 4 so that it does not loosen.

The control device 26 and the actuator control circuit 2
7 etc. are formed as shown in FIGS. 6 and 7, for example.

In the electrical circuit diagram shown in FIG. 6, L ₁ , L ₂ are limit switches operated by the protrusion 19 of the rod 16, and the circled X ₁ , X ₂ , ...X ₆ , CL are:
Relays for the operations shown on the right side, X ₁ , _{X 2} , ...
Reference numeral 8b indicates both solenoids of the electromagnetic switching valve for moving the rod 16. Further, reference numeral 29 denotes a switch for issuing an operation command. In this switch 29, a pulse is input only once at the start, and the operation command and initial positioning are self-maintained at contacts X ₃ and X ₆ , respectively. Note that initial positioning means that the rod 16 is not at the left end in FIG.
If L ₁ is not ON, that is, rod 16
If it is at the right end or halfway, move it to the left end. The two switches 29 in FIG. 6 are in series, and both operate simultaneously. Reference numeral 30 designates a count-up switch which is operated to count the number of times the rod 16 moves in a predetermined direction with the preset-down counter 27a shown in FIG. 7, and to turn off when the count is out. . The contact 31 is provided to select die height advancement or die height retraction, that is, the direction in which the mold clamping force is increased or decreased.If the contact 31 is in the open/closed state shown in FIG. When the solenoid 28a for driving the die height is energized, the electromagnetic clutch 10 is not energized, so the rod 16 moves forward in a connected state, and when the solenoid 28b for driving the die height backward is energized,
Since the electromagnetic clutch 10 is energized, the rod 16 is retracted in a disconnected state. And the above 2
By repeating these operations, the die height decreases one pitch at a time, increasing the mold clamping force. If the open/close state of the contact 31 is opposite to the state shown in FIG. 6, the conditions for energizing and de-energizing the electromagnetic clutch 10 will be reversed, and the die height will increase one pitch at a time, increasing the mold clamping force. decrease.

In FIG. 7, reference numeral 26 is a control device including a correction number calculator as described above, and here, based on signals from setting devices 23, 25 and detector 20, rod 16, column nut 4, and link housing are adjusted. The preset down counter 27 outputs operation commands using pulse signals such as No.
a and actuator control circuit 27 to connect rod 16 and electromagnetic clutch 1.
0 as described above. 32 is an automatic/manual changeover switch, and when it is automatic, the control device 2
The signal No. 6 passes through this switch 32 and directly enters the preset down counter 27a and the actuator control circuit. In the case of manual operation, calculate the number of corrections in advance, set the desired number of corrections in the preset value setting device 27b with the switch 32 set to manual, operate it, and then press the rod 16.
is operated a predetermined number of times to correct the mold clamping force. In the preset down counter _27a , a pulse signal is input once each time relay Outputs up signal. and,
While the mold clamping force is not within the desired range, the rod 16 is driven in pitch, and once the mold clamping force is adjusted within the desired range, the rod is moved to the end of movement position on the side where the column nut 4 is about to loosen. That is, the column nut 4 is held at the movement limit position on the side from which it will not loosen any further to prevent the column nut 4 from loosening.

In the above embodiment, the rod 1 is used as a drive source for rotating the shaft 9 via the pinion 12.
Using a hydraulic device that moves the rod 6 in small reciprocating motions to drive the rod 16 in pitch, the rod 16 is moved several times depending on the deviation value of the actual mold clamping force from the set mold clamping force. It can also be used.

That is, instead of the rod 16 having the rack part 17 and the ram part 18 and the cylinders 15 on both sides, one cylinder with a longer stroke is used, and the piston rod is moved forward while the piston rod is moving forward, without always operating the cylinder at full stroke. It is also possible to use a cylinder device that can be stopped at any time.
In this case, the moving distance of the piston rod of the cylinder is detected using a known moving distance determining device such as a magnetic scale or rotary encoder, and when it is detected that the value has reached a predetermined distance, the oil supply to the cylinder is stopped. Stop, pinion 12 and chain wheel 7b
Make it possible to stop the rotation. It is also possible to use a mechanical locking device to prevent the piston rod from moving. Of course, depending on the relationship between the maximum stroke of the cylinder and the mold clamping force adjustment allowance, it is possible to not only stop the piston rod during the first forward movement, but also to stop the piston rod at the desired speed during the next forward movement after reciprocating the piston rod one or more times. In some cases, it may stop at the position. Furthermore, since the mold clamping force needs to be increased or decreased, it is not only performed when the cylinder moves forward, but also when it retreats.

Also, instead of the rod 16 having the rack part 17 and the ram part 18 and the cylinders 15 on both sides, one cylinder with a short stroke is used, and the rack part 1
The movement stroke of the piston integral with the piston rod part having 7, i.e. the distance S between the end face of the piston part and the inner wall of the cylinder case,
It may also be determined in advance according to the resolution of the fine adjustment device.

A stopper device whose position is adjustable is engaged with the moving members of the cylinder such as the ram portion 18 and the piston, and the rod 16 and the piston rod that are integrated with the moving members of the cylinder, and by adjusting the position of the stopper device, the It is also possible to adjust the moving distance S of the moving member of the cylinder as appropriate and change the resolution of the fine adjustment device as appropriate.

Note that once the moving member of the cylinder has moved to the movement limit position on the side where the column nut 4 is about to loosen, that is, on the side where it will not loosen any further, it is usually necessary to apply hydraulic pressure to the cylinder in order to hold it there. Although there is no, this can also be held down using hydraulic pressure.

Further, instead of these cylinders, another drive device such as a servo motor whose rotation speed or rotation angle can be controlled may be used, and a gear connected to this motor may be meshed with the pinion 12. In this case as well, the motor can be rotated by the required amount using the rotation angle of the motor detected by the rotary encoder, the value directly or indirectly measured of the die height movement amount, etc.

When detecting the mold clamping force by detecting the amount of movement of the die height, for example, a device as shown in FIG. 1 is used.

That is, a magnetic scale type linear scale 33 is attached to the side surface of the machine base 6 at a position corresponding to the link housing 3 along the mold opening direction, and a magnetic head 34 is attached to a part of the side surface of the link housing 3. Ta. The amount of movement of the link housing 3 is detected by the action of the linear scale 33, which is a kind of detector 20 for link housing movement distance or column elongation, and the magnetic head 34, and the linear scale 3
The amount of movement of the link housing 3 and the mold clamping force can be displayed on the display boards 35 and 36 according to the output signal from the link housing 3. 37 is a computing unit. As the linear scale 33, the amount of movement of the link housing 3 is
A device that can be detected in units of 0.01 mm is used, and the display boards 35 and 36 provided at the operator's operating position can be digitally displayed. By employing such a device, the mold clamping force can be determined extremely easily and accurately.

In the above-described embodiment, a synchronized rotational drive device in which four column nuts 4 are simultaneously rotated by a chain drive is used, but instead of this, a synchronized rotational drive device using a conventionally known spur gear device or a worm drive device may be used. It is also possible to use a synchronized rotational drive device with a connecting shaft or the like. In addition, when using a synchronized rotational drive device using a spur gear device, the chain wheel 7b shown in FIG. 3 is not necessary, so a gear is directly attached to the shaft 9 and the gear is meshed with another spur gear.

Of course, the embodiment shown in Fig. 3 without the chain wheel 7b can be used by directly attaching it to the shaft protruding on the opposite side from the output shaft of the geared motor or hydraulic motor that is the drive source of the synchronous rotation drive device. You can also.

In the above embodiment, one fine adjustment device was used to turn four column nuts at the same time, but this could be done by using one or more column nuts using a conventionally known synchronous rotation drive device using a spur gear device. 2-3
Alternatively, only one column nut may be turned.
In that case, disconnect the part of the spur gear that corresponds to the column nut that is not turning, and cut off the transmission of driving force to that part.

Further, the fine adjustment device may be attached to all or several column nuts separately.

There is also a limit switch that sets the rod's movement limit.
L ₁ and L ₂ are detected and the rod is moved in the opposite direction, but this is due to the solenoids 28a and 28
Activate the timer at the same time that b turns on, and after the timeout, turn on the other solenoids 28b and 28a.
By turning it on, it is also possible to repeat the reciprocating motion of the rod.

Furthermore, the electromagnetic clutch 10 can be of the non-energized type as well as of the energized type.

As described above, in the present invention, the mold clamping force adjusting device as described in the claims is used, and in the final step of adjusting the mold clamping force, the movable member of the cylinder is moved to the limit of movement and held there. This prevents the column nut from loosening during operation of the molding machine, and prevents the mold clamping force from loosening.
The column will not be damaged or the molding operation will be hindered.

In addition, in a mold clamping force adjustment device that adjusts mold clamping force by rotating a column nut, a structure is adopted in which a drive device that performs pitch drive is connected to the shaft of a power transmission member for rotating the column nut via a clutch, As a drive device for pitch drive, a drive device is used in which a gear attached to a clutch and a moving member of a cylinder having a rack portion meshed with the gear are slidably provided in the cylinder, and the stroke of the ram portion is Since the operating pitch of the power transmission member can be regulated by the above, fine mold clamping force adjustment can be reliably and easily performed using a conventional die height adjustment device, and automatic adjustment can also be easily performed. can.

A clutch is used in this adjustment device, and in particular, if a non-excited actuated electromagnetic brake is used as the clutch, conventionally, the electromagnetic brake is attached to the motor for driving the column nut, and the motor is activated. When stopping rotation, it was necessary to immediately stop the rotation by the action of the electromagnetic brake and to hold the motor so that it does not rotate even after the motor has stopped, but this is no longer necessary. That is, in the present invention, the clutch in the mold clamping force adjustment device fulfills its role, and a drive device is provided to perform pitch drive, and a device is provided that prevents the ram from moving further when it reaches the end. These actions lock the rotation of the chain wheel, etc., and therefore prevent the chain and column nut from loosening, so that the mold clamping force does not drop even during continuous use over a long period of time.

In addition, in the present invention, a cylinder is used as a part of the fine adjustment device and is operated by hydraulic pressure, so that a large torque is unnecessary and the cylinder can be made compact. In other words, the allowable stress of the material in the ram or piston rod is usually
1000Kg/cm ² , but the hydraulic pressure acting on it is usually 140Kg/cm ² , so the allowable stress of the material is about 7 times the hydraulic pressure. The pressure receiving area and rod part can be reduced.

[Brief explanation of the drawing]

The drawings show one embodiment of the apparatus for carrying out the present invention, in which Fig. 1 is a front view, Fig. 2 is a left side view, Fig. 3 is a vertical cross-sectional view taken along the line - - of Fig. Third
Fig. 5 is a block diagram showing the control method, Fig. 6 is an electric circuit diagram of the control device, Fig. 7 is a sectional view taken along the line -
The figure is a control explanatory diagram. 1... Fixed plate, 2... Movable plate, 3... Link housing, 4, 4a... Column nut, 5... Mold clamping cylinder, 6... Machine base, 7... Motor, 7a, 7b
...Chain wheel, 8...Chain, 9...Shaft, 10...Electromagnetic clutch, 12...Pinion, 15...Cylinder case, 16...Rod, 17...Rack gear, 18...
Ram, 26... Control device, 27... Actuator control circuit, 27a... Preset down counter, 2
8a, 28b... Solenoid, 33... Linear scale, 34... Magnetic head.

Claims (1)

[Claims] 1. When adjusting the mold clamping force by turning the column nut, the cylinder device that performs pitch drive according to the resolution of the mold clamping force adjustment device determined by the moving distance of the moving member of the cylinder is rotated by the column nut via the clutch. The column nut is rotated by pitch driving while disconnecting the connection to the power transmission member for the cylinder, and in the final step of adjusting the mold clamping force, the moving member of the cylinder is moved to the movement limit position on the side where the column nut is about to loosen. A method for preventing loosening of a column nut for a molding machine by holding a movable member at the movement limit position with a clutch connected to prevent the column nut from loosening.