JPH0160342B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection device for a die-casting machine, and particularly to an injection device for a die-casting machine that can reduce the injection speed just before the end of injection when performing high-speed injection. It is.

Conventionally, for example, as shown by the solid line in Figure 1, the speed is decelerated just before the end of injection to prevent the generation of peak pressure during the forward movement of injection and the accompanying impact, thereby preventing undue force on the molten metal, mold, etc. In order to prevent this from occurring and to obtain injection products of stable quality, an injection cylinder 1 having a structure as shown in FIG. 2, for example, has been used.

In Fig. 1, the horizontal axis is the injection stroke, the vertical axis is the injection speed, O is the injection start position,
A is a high-speed switching position where a switch from low speed to high speed is commanded, and B is a high-speed start-up position where the speed actually begins to increase after receiving a command at position A, which is, for example, 20 to 30 mm ahead of position A. E is the injection end position, D is the deceleration start position, for example, about 10 mm before the E position, and F is the deceleration end position, that is, the deceleration stable start position. In addition, S is a change standard stroke for determining whether or not to change the deceleration position according to the size of D-A when changing the A position. It will be done. In addition,
In FIG. 1, the speed diagram indicated by the dotted line is a diagram showing the normal limit when the deceleration position is not moved,
The figure shows the high-speed switching position in which point C is a change reference stroke S before position D. Note that the modified reference stroke S' is based on the E position, which is the injection end position.

The injection cylinder 1 shown in FIG. 2 has a piston 5 in both directions of a cylinder body 2 and a hollow tube 4 which is inserted from the rear of the cylinder body 2 and has a hole 3 communicating inside and outside only on the outer peripheral surface near the tip. A piston rod 6 is slidably provided and integrated with the piston 5, and has a cavity 7 inside it, and a hole 8 communicating inside and outside at its rear end. Reference numeral 9 denotes a check valve provided at the rear of the hollow tube 4 toward the first chamber 10 on the head end side. When hydraulic oil is supplied to the first chamber 10 of the injection cylinder 1 having such a structure, the piston 5 and the piston rod 6 move forward. At that time, if the outlet of the second chamber 11 on the rod end side to the outside of the injection cylinder 1 is closed, the hydraulic oil in the second chamber 11 can be transferred to the hole 8, the cavity 7, the hole 3, the hollow tube 4, and the check valve 9. Go through it and enter the first room 10. Therefore,
Due to the action of the run-and-land circuit, the piston 5 and the piston rod 6 move forward with a relatively small amount of hydraulic fluid. When the hole 3 of the hollow stem 4 is closed by the inner surface of the piston 5 near the end of the forward movement, the run-around circuit is interrupted and the forward speed of the piston 5 and the piston rod 6 is reduced. In addition, in the conventional injection cylinder 1 of this type, the procedure for setting the optimal casting conditions is to first manually move the mounting position of the hollow tube 4 back and forth to set the deceleration position where burrs do not blow. After getting used to the product, the workers concentrated on adjusting the high-speed switching position while observing the surrounding conditions of the product.

On the other hand, recent research results in casting technology have revealed that in order to cast die-cast products with fewer cavities, it is better to shorten the high-speed section. For this reason, the high speed switching position tends to be set closer to the injection end position, and it is likely that the high speed will not reach the specified value due to deceleration, which is a factor that makes it difficult to set the casting conditions. It's getting better.

In addition, not only the high-speed switching position, but also the magnitude of the deceleration of the injection speed near the end of injection, the magnitude of the deceleration gradient, the deceleration start position, the deceleration It has become necessary to perform injection by changing deceleration conditions such as the end position in order to obtain high-quality injection products.

The present invention is capable of automatically changing the conditions for decelerating the injection speed near the end of injection in response to changes in the high-speed conditions.

In the present invention, a high-speed switching position setting device, a high-speed switching sequence control device, a high-speed speed setting device, a high-speed speed control device, and a deceleration position setting device for an injection cylinder are provided. The injection device of a die-casting machine equipped with a deceleration control device is equipped with a change standard stroke setting device that sets the stroke difference between the deceleration position and the high speed switching position, and the change standard stroke setting device is used to set the current deceleration position, the high speed switching setting position, and the changing standard stroke setting value. Equipped with a comparator that makes a comparison and instructs whether it is necessary to change the deceleration start position, and when the high speed switching position is closer to the injection end position than the predetermined change reference position,
Equipped with a control device that can automatically change the deceleration position or deceleration rate in conjunction with the changing operation of the high-speed switching position, and a deceleration rate setter and a deceleration rate setter when decelerating the injection speed following high-speed injection. The present invention is equipped with a deceleration ratio control device and a deceleration speed control device that can manually and automatically change the deceleration amount and deceleration speed in conjunction with changes in the high speed.

Next, the present invention will be explained with reference to embodiments shown in the drawings.

The block diagram shown in FIG.
This shows an example.

In the structure of the injection cylinder 1 shown in FIG. 3, the parts having the same structure as the injection cylinder 1 shown in FIG.

In the injection cylinder 1 shown in FIG. 3, a motor 24 and a deceleration position detector 25 are installed behind the hollow tube 4 to move the hollow tube 4 back and forth and adjust the deceleration start position at which the piston 5 begins to close the hole 3. Installed. A tube 30 is provided in the hollow tube 4 so as to be freely slidable in the axial direction, for adjusting the number and degree of opening of the holes 3 of the hollow tube 4 to adjust the deceleration rate, that is, the deceleration gradient.
At the rear end of the tube 30, a motor 31 for setting the amount of deceleration and a detector 32 for determining the position of the tube 30, that is, the amount of deceleration were attached. The hollow tube 4 was moved forward and backward by the motor 4 via the block 33, and the motor 31 was attached to the block 33.
A hole 30a and a long hole 4a are provided near the rear ends of the tube 30 and the hollow tube 4, respectively, so that when the injection cylinder 1 is moving forward, the hole 8, the cavity 7,
The oil that entered the hollow tube 4 through the hole 3,
It is possible to enter the first chamber 10 through the tube 30, the hole 30a, the elongated hole 4a, and the check valve 9. When the hole 3 is blocked by the piston 5, this run-a-land circuit is cut off and the speed is reduced. Second chamber 11 and first chamber 1 of injection cylinder 1
0, a run-a-land circuit 34 is provided outside the injection cylinder 1, and in the run-a-land circuit 34,
A flow rate adjustment valve 35 and a pilot check valve 36 are provided for setting the deceleration speed, and the flow rate adjustment valve 35 is equipped with a motor 3 for adjusting the opening degree and setting the deceleration speed.
7, and a detector 3 for the opening position, that is, the deceleration speed.
8 was installed.

A striker 12 moves forward and backward integrally with the piston rod 6, and a magnetic scale 13 and a magnetic head 14 are attached to the striker 12 to detect the injection stroke. 15 is magnetic head 1
A converter 4 converts the analog signal waveform into a pulse signal of one pulse per 1 mm stroke, and 16 is a stroke counter for counting this pulse signal. 18 is a setting device for setting switching position A from low-speed injection to high-speed injection; 19
is the signal from the setting device 18 and the stroke counter 1
This comparator compares the injection stroke signals from 6 to 6 and outputs a high-speed switching signal to the high-speed switching sequence control device 20. Reference numeral 21 is a change reference stroke S setting device that advances the deceleration start position D when the stroke difference between the deceleration start position D and the high speed switching position A becomes smaller than the value set here;
are a subtracter and an adder 22a that subtract the value of the high-speed switching position setter 18 from the current deceleration start position Di,
Output of decelerator 22 and change reference stroke setter 2
The value of 1 is compared by the comparator 26 and outputs as a command signal whether or not the deceleration start position D needs to be changed.
Reference numeral 23 denotes a motor 2 that moves the hollow tube 4 of the injection cylinder 1 back and forth based on a signal from the comparator 26.
a positioning control section 23a for controlling the positioning of No. 4;
25 is a motor drive unit, and 25 is a deceleration position detector, which is a rotary encoder that detects the rotation angle of the motor 24 and feeds it back to the positioning control unit through an input buffer 25a. Instead of the simple motor 24, a pulse motor or other actuator may be used to move the hollow tube 4 back and forth. 27 is a setting device for setting the deceleration start position in the case of manual operation, 28 is a manual-automatic changeover switch, and 29 is a command push button switch used in manual operation.

The above-mentioned control device operates in conjunction with the change operation of the high-speed switching position when the high-speed switching position A is closer to the injection end position than a predetermined change reference position shown as the limit point C of the high-speed switching position in FIG. This is a control device that can automatically change the deceleration position, so that when the high-speed switching position moves forward, the deceleration position can be moved forward, and when the high-speed switching position moves backward, the deceleration position can be moved backward. did.

When the manual/automatic changeover switch 28 is set to manual, the deceleration position can be remotely controlled using the deceleration start position setter 27 and the command push button switch 29 on the operation panel. First, a desired deceleration position is set in the deceleration start position setter 27, and when the command push button switch 29 is pressed, the positioning control section 23 compares the current deceleration position Di from the deceleration position detector 25 with the set position and calculates the deviation. If so, it determines whether the motor 24 rotates forward or reverse, and outputs a start command to the motor drive section 23a. The motor drive unit 23a is a high-power circuit for starting, stopping, forward and reverse rotation of the motor 24. When the hollow tube 4 moves to the point where the measured deceleration position and the set position match, the positioning control unit 23
outputs a stop command to the motor drive section 23a.

When the manual-automatic changeover switch 28 is set to automatic, the position of the hollow tube 4 is determined based on the value of the high-speed switching position A set in the setting device 18, the value of the change reference stroke S set in the setting device 21, etc. Control. In this case, the deceleration start position D is detected by the subtractor 22 based on the signal Di sent from the deceleration position detector 25 through the input buffer 25a and the deceleration start positioning control section 23.

Now, suppose the current position of deceleration start position D is 1000mm.
If the setting value in the change reference stroke setter 21 is 50 mm, then the high-speed switching position setter 18
If the setting value in is 700mm,
Since 1000mm-700mm=300mm>50mm, there is no need to change the deceleration position, so no command signal is sent to the motor 24. High-speed switching position setter 18
If the setting value in is 960mm,
Since 1000 mm - 960 mm = 40 mm < 50 mm, a command signal is sent to the positioning control circuit 23 to change the set position so as to move the hollow tube 4 forward by 10 mm.

In this way, if the difference between the deceleration start position and the high-speed switching position A is the same as or larger than the change standard stroke S, the deceleration start position will not be changed, and conversely, the difference between the deceleration start position D and the high-speed changeover position A will be the change standard. When it is smaller than the stroke S, the deceleration start D is advanced from the current position to a position equal to the sum of the high speed switching position A and the change reference stroke S, so that the deceleration is hardly applied or not at all.

Note that here, when the difference between the deceleration start position D and the high speed switching position A is smaller than the change reference stroke S, the deceleration start position D can be moved forward a little to cause deceleration, but in this case, According to the amount of advance of the deceleration start position D, that is, according to the amount of advance of the high speed switching position A, the deceleration amount G to be described later is determined.
It is also possible to control the speed by increasing the speed so that the deceleration state can be sufficiently applied.

Note that instead of comparing the stroke difference between the deceleration start position D and the high-speed switching position A with the change standard stroke S, the same result can be obtained by comparing the stroke difference between the injection end position E and the high-speed change position A with the change standard stroke S'. can be controlled. In this case, the procedure for calculating the injection end position E is to first set the biscuit thickness using the biscuit thickness setting device, then perform blank firing once.
Next, the read command button for the injection stroke counter 16 is pressed. Then, the present control device reads the injection stroke at that time, that is, the branch branch end stroke, and obtains the difference between the injection stroke and the biscuit thickness as the injection end position E.

39 is a high-speed speed setting device, and 40 is a high-speed speed control section.The high-speed speed control section 40 controls a high-speed flow rate regulating valve (not shown) to obtain a desired high-speed injection speed.

41 is a setting device for setting the deceleration speed near the end of injection, and 42 is a deceleration speed control section, which controls the motor 3 for setting the deceleration speed via the motor drive section 43a.
7 to control the deceleration speed. 44a is a deceleration speed valve opening detector 38 which is a rotary encoder.
This is an input buffer section for providing feedback from the deceleration control section 42 to the deceleration control section 42.

43 is a subtractor for subtracting the value of high speed setting device 41 from the value of high speed setting device 39; 44 is a storage circuit; 45 is a divider; 46 is a multiplier; 47 is a storage circuit; 48 is a comparator; 49 5 is a manual/automatic changeover switch, 50 is a control unit for deceleration sum, that is, deceleration gradient, 51 is a motor drive unit, and 52 is an input buffer unit.These are linked as shown in FIG. The motor 31 and the deceleration (position of the tube 30) detector 32 are also connected.

Reference numeral 53 is a deceleration amount setter for manually setting the deceleration amount, and 54 is a command push button switch for manually setting the deceleration amount.

The deceleration amount can be automatically controlled from high speed and deceleration speed by switching the changeover switch 49 to automatic, or it can be set manually by switching the changeover switch 49 to manual and using the deceleration value setting device 53. You can also do it.

Using the device shown in Figure 3, with the deceleration start position and injection end position (deceleration stable start position) kept constant,
When the deceleration rate is automatically corrected in accordance with a change in the setting of the high speed or deceleration speed, it is performed as follows.

As shown in Figure 4, if the high speed is W _H , the deceleration speed is V _D , the deceleration gradient is G, and the distance from the deceleration start position D to the deceleration end position F is l, then G = - (V _H - V _D / l) Now, if the high speed V _H is changed from V _Hi to V _Hi+1 , the slope before the setting change G _i = - (V _Hi - V _D / l) The slope after the setting change G _{i+ 1} = −(V _Hi+1 −V _D /l) From now on, G _i+1 / _Gi = V _Hi+1 −V _D /V _Hi −V _D , so the slope G _i+1 after changing the settings is , G _i+1 = G _i (V _Hi+1 −V _D /V _Hi −V _D ……(1).

This formula can be used in the same way when changing the setting of the deceleration speed.

As shown in FIG. 4, when controlling the deceleration gradient G according to changes in the high speed _VH while keeping the deceleration start position D constant, set the changeover switch 28 to manual using the device shown in FIG. Switch the changeover switch 49 to automatic. Then, according to the values before and after the change of the set high speed and deceleration speed, the calculation of equation (1) is performed in each device indicated by 43 to 48, and according to the values, the motor 31 for setting the deceleration rate is rotates a predetermined amount,
The position of the tube 30, ie, the degree of opening of the hole 3, changes to obtain a desired deceleration gradient.

Next, the deceleration gradient G, deceleration speed V _D , and injection end position F are kept constant in advance, and the high speed V _H
When the deceleration start position D is automatically corrected in accordance with a change in the deceleration start position D, the deceleration start position is determined according to FIG.

In this case, when the high speed is changed from V _Hi to V _Hi+1 , the deceleration gradient G=-△V/△D=V _Hi+1 -V _Hi /
△D, and from now on, the amount △D by which the deceleration start position is corrected from Di to V _i+1 is △D=V _Hi+1 −V _Hi /G, so the deceleration start position after automatic correction is D _{i +1} becomes D _i+1 =Di+△D=D _i+ V _Hi+1 −V _Hi /G.

When controlling the deceleration start position D according to the high speed _VH , a control circuit as shown in FIG. 6 is used. Note that FIG. 6 shows only directly related parts, and the same parts as those shown in FIG. 3 are designated by the same reference numerals as those shown in FIG. 3, and the explanation thereof will be omitted.
Note that 55 is an adder.

Next, the deceleration gradient G, deceleration speed ratio R=V _D /V _H , and deceleration start position D are kept constant in advance, and the speed V _D and deceleration end position F are automatically corrected according to changes in the high speed V _{H. In the case of} The deceleration end position after changing the speed will also be determined automatically.

In this case, the motor 37 for setting the deceleration speed inputs the setting value of the high-speed speed setting device 39 and the setting value of the deceleration speed ratio setting device (not shown) into a multiplier,
According to the output of this multiplier, the deceleration speed control section 42,
It is automatically controlled as appropriate via the motor drive section 43a.

Further, if the deceleration speed is changed in accordance with the high speed in this manner, the deceleration end position is automatically determined by other factors as described above.

In the above embodiment, the injection cylinder 1, which has a somewhat complicated structure as shown in FIG. 3, was used as the injection cylinder. This can also be carried out by using a device in which a valve is provided in the injection circuit, controlling this pulse motor as appropriate, and controlling the opening degree and opening/closing speed of the flow rate regulating valve.

As described above, since the present invention has the configuration as described in the claims, conventionally the operator could adjust the deceleration conditions such as the deceleration position and deceleration speed by reaching the position of the handle at the rear of the injection cylinder, etc. What used to be done manually by turning the handle at the wheel can now be controlled remotely from the control panel, dramatically improving operability and making it possible to fine-tune the deceleration conditions. Furthermore, the deceleration conditions can be automatically, reliably and easily changed in response to changes in high-speed conditions such as high-speed injection speed and high-speed switching position. Since the deceleration conditions can be appropriately adjusted according to the high-speed conditions, it becomes easier to set the casting conditions, and it becomes easier to obtain high-quality injection products.

In other words, when performing injection by automatically changing the increase/decrease value of deceleration as a deceleration condition in accordance with the increase/decrease value of high-speed injection speed as a high-speed condition, for example, if the high-speed injection speed increases, the amount of increase Since the deceleration rate increases accordingly, the deceleration speed at the desired deceleration end position can be set to a desired value. Then, the speed is sufficiently decelerated near the injection end position, so burrs are not blown away from the mold mating surface during injection, and vibrations and cracks are less likely to occur due to shocks being applied to the mold or machine. The shape of the mold cavity changes slightly when excessive force is applied to the mold, and the shape of the injection product is less likely to change slightly, making it possible to obtain injection products of stable quality. In addition, if there are pockets in the mold cavity that make it difficult for gas to escape, the degree of turbulence in the molten metal can be suppressed as much as possible by increasing the deceleration rate near the injection end position to reach the desired deceleration speed. , it is possible to minimize the entrainment of gas into the molten metal, improve gas escape, and make it easier to obtain a void-free injection product.

Such an effect can also be obtained by retracting the deceleration start position in accordance with the amount of increase in high speed while keeping the deceleration constant. In addition, if the deceleration start position is advanced according to the amount of decrease in high speed while keeping the deceleration rate constant, the desired deceleration speed can be obtained at the desired position, and the same effect as described above can be obtained. can be obtained.

In addition, if the increase or decrease in deceleration speed is slightly changed in proportion to the increase or decrease in high-speed injection speed, for example, if the high-speed speed increases, the deceleration speed will also increase slightly in proportion to it, but it will be If burrs do not blow from the mold mating surfaces, vibrations, etc. are less likely to occur, and the mold cavity is not so complicated that gas can be discharged relatively easily during injection, the deceleration speed should be increased in addition to the high speed. The injection filling time is slightly shorter due to the larger size, and the molten metal circulates within the mold cavity slightly faster, and the molten metal does not cool down, making it possible to obtain high-quality injection products with good hot water circulation.

In addition, when controlling using the high-speed switching position as the high-speed condition and the deceleration position as the deceleration condition, the stroke between the current deceleration position and the high-speed switching position is the stroke between the predetermined deceleration position and the high-speed switching position. Compared to the change standard stroke setting value,
During a stroke where the high-speed switching position is closer to the injection end position than the predetermined change reference position, if the deceleration position is automatically changed in conjunction with the high-speed switching position change operation, the injection will normally end. In cases where the desired high speed cannot be obtained near the position, it is possible to obtain the desired high speed, which improves the flow of the molten metal, reduces cooling of the molten metal, and achieves the desired high quality injection. You can get the product.

Furthermore, using a high-speed switching position as a high-speed condition,
When controlling using the deceleration rate as the deceleration condition,
When the high-speed switching position is closer to the injection completion position than the predetermined change reference position, if the deceleration rate is automatically increased in conjunction with the high-speed switching position change operation, the desired position can be reached at the desired position. A deceleration speed can be obtained, and the same effect as when the high speed is used as the high speed condition and the deceleration value or the deceleration position is used as the deceleration condition can be obtained.

The injection conditions for obtaining high-quality injection products depend on many conditions, such as the shape and dimensions of the various injection products, how to cut the mold gate, how to provide gas vent grooves, mold temperature, and molten metal temperature. However, when actually performing injection molding, various controls such as those shown in the present invention can be appropriately selected and performed.

[Brief explanation of drawings]

Fig. 1 is a diagram showing changes in injection speed with respect to injection stroke, Fig. 2 is a vertical cross-sectional view showing a conventional injection cylinder, and Figs. 3 and 6 are control systems showing different embodiments of the present invention. The block diagram of FIGS. 4, 5, and 7 are explanatory diagrams showing states in which the deceleration conditions change in response to changes in the high-speed conditions, respectively. 1...Injection cylinder, 4...Hollow tube,
16... Stroke counter, 18... High speed switching position setter, 21... Change reference stroke setter, 24... Motor for setting deceleration start position, 27...
...Deceleration start position setter, 31...Motor for setting deceleration rate (gradient), 35...Flow rate adjustment valve, 37...
...Deceleration speed setting motor, 39...High speed setting device, 41...Deceleration speed setting device, 53...Deceleration rate (gradient) setting device.

Claims (1)

[Claims] 1. A high-speed switching position setting device for an injection cylinder, a high-speed switching sequence control device, a high-speed speed setting device,
Changes that set the stroke difference between the deceleration position and the high-speed switching position in the injection device of a die-casting machine equipped with a high-speed speed control device, a deceleration position setting device, and a deceleration control device that can decelerate the injection speed following high-speed injection. Equipped with a reference stroke setter, and a comparator that compares the current deceleration position, high-speed switching setting position, and change reference stroke setting value to instruct whether or not to change the deceleration start position. When it is closer to the injection end position than
Equipped with a control device that can automatically change the deceleration position or deceleration rate in conjunction with the changing operation of the high-speed switching position, and a deceleration rate setter and a deceleration rate setter when decelerating the injection speed following high-speed injection. An injection device for a die casting machine, which is equipped with a deceleration rate control device and a deceleration speed control device that can manually or automatically change the deceleration rate or deceleration speed in conjunction with a change in the high speed.