JPH0367465B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention revolves a plurality of mold opening/closing units holding molds on a rotary table, and a plurality of mold opening/closing units that hold molds are rotated at equal intervals on the orbit. The present invention relates to a method for driving and controlling a rotary table of a rotary die casting machine that performs casting operations in the order of steps at a work station.

[Prior Art] Previously, the applicant developed a rotary die-casting machine with the aim of significantly improving productivity. This is achieved by installing mold opening/closing units that hold molds at positions that divide the outer circumference of the rotary table into multiple parts in the circumferential direction. Each work is performed in the order of steps while stopping at each work station.

To give an overview of the entire rotary die-casting machine, the rotary die-casting machine 1 has a first station ₂ , a second station 3, and the angles formed by the center lines L 1 , L ₂ , L ₃ shown in FIG. 5 are 120 degrees. , the third station 4 is the rotary table 1
4, and as shown in FIG.
Hollow shaft 1 shaped like a reverse funnel to rotate the table
3 includes a diver 6 and is fixed upright concentrically with the diver 6. A rotary table, generally designated by the reference numeral 14, is rotatably supported on this hollow shaft 13 via upper and lower ball bearings 15, 16. has been done. As shown in FIG. 7, this rotary table 14 includes a center frame 17 which is shaped like an equilateral triangular box in plan view, and three frames arranged at positions corresponding to each side of the triangle.
Set of mold opening/closing unit holding parts, 18A, 18B, 1
8C and fan-shaped support plates 19A, 19B, and 19C supported between adjacent mold opening/closing unit holding parts. As shown in FIG. 8, the gear 20 is a gear that meshes with a pinion 100 that is directly connected to a motor 101 that is fixed to the table support portion 5a on the base platen 5 side, and is fixed to the rotary table 14. Rotation of the motor 101 according to a command from the rotary table 1
4 is configured to rotate intermittently by 1/3 rotation at predetermined timing. This stop positioning is done by using a knock pin 1 with a tapered convex portion at the tip.
02 is actuated by a cylinder mechanism 103 provided on the base platen 5, and the knock pin 102
is inserted into tapered recesses 104a to 104c of the same shape provided in the center frame 17 of the rotary table 14 for each position of the rotary table 14 that matches each station.

The first station 2 also includes a base platen 5 which is integrally formed with a table support part 5a having a circular shape in plan view and an injection part 5b having an isosceles triangular shape in plan view and is fixed on a foundation on the floor surface. (See Figure 6). At three locations, the center of the table support part 5a and both ends of the isosceles triangle base of the injection part 5b,
Tie bars 6 and 7 are installed vertically.
A tie bar hole of a cylinder platen 8 formed in an isosceles triangular shape is fitted into the upper end of the tie bar 7, and the tie bars 6 and 7 are firmly fixed by nuts 9. The frame is formed in this way and the first station 2
is provided with a mold clamping device 10, an injection device 11, and an automatic hot water supply device 12.

The second station 3 includes an extruded frame 21 fixed to the cylinder platen 8 and installed horizontally and having an isosceles triangular shape in plan view. A tie bar 23 is installed between the extrusion frame 21 and the
(See Fig. 6). The second station 3 having a framework formed in this way includes a mold setup device 25, a product take-out device 26, as shown in FIGS. 5 and 6.
It includes a protruding cylinder 27 and an extruding cylinder 28. The mold setup device 25 operates a mold opening/closing unit, generally designated by the reference numeral 29, at the start of casting work, mold replacement, maintenance, etc.
Mold opening/closing unit holding parts 18A, 18B, 18C
A frame 3 extends from below the mold opening/closing unit holder 18A (18B, 18C) in the direction of the center line _L2 and is fixed to the floor surface.
0, and on this frame 30, a large number of rollers 32 are arranged in parallel on both sides, which are driven by a motor 31 via a belt and chain to rotate selectively in forward and reverse directions.

The mold opening/closing unit 29 holds a fixed mold 33 and a movable mold 34, and clamps and closes the movable mold 34.
It is used to perform operations such as opening a mold.

Furthermore, the third station 4 is not equipped with a frame like the other stations 2 and 3, and the mold opening/closing unit 29 newly supplied to the rotary table 14 at the second station 3 and the mold opening/closing unit 29 from which the product has been removed are not provided. A spray device 35 is provided for cleaning the opened molds 33 and 34 of the unit 29 and spraying a mold release agent thereon. This spray device 35 is supported by a frame 36 and is connected to the hydraulic cylinder 3.
It is equipped with an arm 38 that moves forward and backward at 7, and arm 3
A spray head 39 is attached to the tip of the spray head 8 . Then, a spray head 39 is moved between the two molds 33 and 34 using a hydraulic cylinder 37, cleaning is performed by blowing out air, and a mold release agent is applied by blowing out air and mold release agent. Reference numeral 40 denotes a conventionally known insert insertion device for inserting inserts into the molds 33 and 34 as necessary. After the work at the third station 4, the mold opening/closing unit 29, which has temporarily clamped the molds 33 and 34, is moved to the first station 2 by the rotation of the rotary table 14.
The mold rotates around and stops, and mold clamping and injection are performed.

Mold clamping device 10 in the first station 2
is equipped with a cylinder 41 integrally formed with the cylinder frame 8, and a main ram 43 that is fitted into the cylinder 41 and can be raised and lowered by pressure oil introduced from a port 42. A moving platen 44 is fixed. Further, a pair of pullback cylinders 45 are fixed to the upper surface of the cylinder platen 8, and are located on both sides of the cylinder 41, and their piston rods 46
passes through the cylinder platen 8 and its working end is fixed to the moving platen 44. With this configuration, when pressure oil is introduced from the port 42 and the main ram 43 is lowered,
The molds 34, 34, which have been temporarily clamped, are pressurized via the mold opening/closing unit 29 and are clamped. Further, after the pressure oil above the main ram 43 is removed, the oil is sent to the pullback cylinder 43, whereby the moving platen 44 is raised and the molds 33, 34 are released from the pressurized mold clamping.

The injection device 11 includes an injection cylinder 48 that is supported by a tie bar and a frame 47 that hang down from the base platen 5, and a plunger 50 is connected to a piston rod 49 that is raised and lowered by hydraulic pressure through a coupling 51. This plunger 50 is fitted into an injection sleeve 54 supported by a block 53 which is moved up and down by a ram 52.
The injection sleeve 54, which is raised together with the block 53 by the ram 52, is fitted into the fixed sleeve on the fixed mold 33 side, and when the plunger 50 is raised by the injection cylinder 48, the molten metal in the injection sleeve 54 is clamped. The liquid is injected into the cavities of molds 33 and 34.

Further, the automatic hot water supply device 12 includes a frame 55 erected on the base platen 5, and a device main body 57 supported by the frame via a four-bar link 56. A melting furnace 59 filled with is placed on the floor. When the injection cylinder 48 is tilted by a tilting device (not shown) to the position shown by the chain line _L4 in the figure, the ladle 60 at the tip of the device main body 57 plunges into the molten metal of the melting furnace 59 by the drive of the servo motor 58 or the like. It is configured to draw up the molten metal and move it to a position concentric with the chain line L ₄ via the four-node ring 56 to supply the molten metal into the injection sleeve 54 . After pouring, when the molten metal solidifies and begins cooling, pressure oil is removed from the port 42 and at the same time, pressure oil is introduced into the pullback cylinder 45.
The moving platen 44 is raised to release the pressure. Mold 3 after pressure clamping, injection, and pressure release
The mold opening/closing unit 29, which holds the molds 3 and 34 in a temporarily clamped state, rotates to the second station 3 and stops due to the rotation of the rotary table 14, and the mold is opened and the product is taken out.

That is, the protruding cylinder 27 is equipped with a piston rod that is protruded by hydraulic pressure into the cavities of the molds 33 and 34 where mold opening is started, and thereby the product is held on the side of the movable mold 34. It is constructed so that it can be opened from the mold. Further, the extrusion cylinder 28 is equipped with an extrusion pin at the tip of the piston rod that is lowered by hydraulic pressure and protrudes into the cavity of the movable mold 34 via the mold opening/closing unit 29, and extrudes the product out of the cavity. It is structured like this.

The product take-out device 26 receives the product extruded from the movable mold 34, cools it with water, and then discharges the product onto the floor or the like. 34, and a puller 64 that moves back and forth in a direction orthogonal to the tray 62 using a hydraulic cylinder 63, and receives the product extruded from the mold 34 at the forward position. When the receiving tray 62 retreats to the illustrated position, the puller 64, which has been waiting at the advanced limit beyond the receiving tray 62, retreats and pulls out the products onto the basket 65. A link mechanism (not shown) is attached to the basket 65, and when the link mechanism is moved by a driving device, the basket 65 reciprocates between the illustrated position and the cold water tank while holding the product, thereby cooling the product. The cooled product is configured to slide on the chute and be discharged onto the floor or the like. After taking out the product, the mold opening/closing unit 29 moves to the third station 4 with the mold open.

The casting operation has been explained in the order of steps for one set of mold opening/closing units 29, but the rotary table 1
Each time the other mold opening/closing unit holders 18B, 18C of 4 stop at the second station 3, the mold opening/closing unit 29 is supplied thereto and the mold opening/closing unit 29 is moved to each station 2,
By performing the same operations as above in steps 3 and 4, a normal casting cycle begins.

The driving method for intermittently rotating and stopping this rotary table is configured as follows.

As shown in FIG. 7, below the rotary table 14 rotating in the direction of the arrow, a cam 120 is integrally attached to the gear 20 that drives the rotary table 14, as shown in FIGS. 8 and 9. Teru. Cam 12
0 indicates the number of work stations, that is, the same number as the number of stop positions of the table. In the illustrated example, there are three stop positions, so the cam 120 also has 120.
Three pieces a to c are provided at equal intervals on the circumference. A plurality of recesses 133 are formed in the front surface 131 of the cam 120, as shown in FIG.
3 reaches the front end 132 of the cam 120 and is provided wider than the other recesses 133.

Furthermore, the proximity switches for detecting the cam 120 are provided in pairs on a base 123 for proximity switches so as to be shifted up and down, and the base 123 for proximity switches is held stationary by a bracket 122 with respect to the rotation of the rotary table. It is fixed to a member such as the base platen 5 (see FIG. 10). and,
Of the two proximity switches, the upper proximity switch 125 is set at a height that allows it to detect the front surface 131 of the cam 120 attached to the gear 20 with bolts 121, and the lower proximity switch 126 is set at a height that allows the cam to be detected. The base 123 is fixed at a height at which a plurality of recesses 133 provided in the base 120 can be detected.

Therefore, the cam 120 is connected to the rotary table 14,
That is, as the gear 20 rotates, it rotates with respect to a set of fixedly installed cam detection proximity switches 125 and recess detection proximity switches 126, and the direction of rotation progresses to the right side of the drawing as shown by → in FIG. Then, first, the edge 13 of the front part 131 of the cam 120
2 is detected by the upper cam detection proximity switch 125. At this time, the lower recess detecting proximity switch 126 detects the first recess 133 of the cam 120.
Since the cam 120 is located in the cam 120, it has not been detected yet. If the rotation continues as it is, the cam detection proximity switch 125 will continue to detect the front part 131 of the cam 120 as shown in _S1 of FIG. 12. On the other hand, when the lower recess detecting proximity switch 126 approaches the recess 133 and the first edge 141 of the surface 131, the cam 120 is detected by the protrusion 134, and then the cam 120 approaches the next recess 133.
20 is not detected, and when the second edge 142 comes further, the cam 120 is detected again, and in this way, the cam 120 is repeatedly detected at each position of the convex portion 134 of the uneven portion. That is, the upper cam detection proximity switch 12
Reference numeral 5 indicates the presence or absence of the cams 120 (120d to 120c) and outputs a signal _S1 , and the lower recess detection proximity switch 126 detects the recesses provided at equal pitches P on each cam. 133 and protrusion 134
In response to this, a pulse-like signal _S2 is output. Therefore, the recess detection proximity switch 126 detects the recess 133 and the projection 134 by generating a pulse signal every time the protrusion 134 provided on the cam 120 passes just in front of the recess detection proximity switch 126. By counting these pulse signals, the position of the rotary table 14 can be accurately determined. Based on this pulse signal, the rotary table 14 can be stopped at a predetermined stop position with the required deceleration. I can do it.

That is, as described above, the cam 120 and the recess detecting proximity switch 126 constitute the position detecting means for the rotary table 14, and the cam 120 has a large number of recesses 13.
_14. As shown in FIG. ₂ to counter 135
The flow rate control valve 140 is controlled by the controller 136 based on this count value, thereby changing the rotational speed of the rotary table 14 from high speed V ₁ to each pulse of the pulse signal S ₂ as shown in FIG. The deceleration is made to decelerate sequentially with a constant deceleration each time. By decelerating the rotational speed of the rotary table 14 for each pulse, for example, by the position pulse signal S ₂ generated by the position detecting means, a predetermined number of pulses, that is, the recess 133 provided in the cam 120 is The rotary table 14 is stopped when a predetermined number of recesses 133 are located at the recess detection proximity switch 126.

Therefore, in each stop operation, the cam 120
The rotary table 14 can be accurately stopped at a predetermined stop position using a large number of recesses 133 provided therein as references.

FIG. 12 is a diagram showing the output signal S ₁ of the cam detection proximity switch 125 and the output signal S ₂ of the recess detection proximity switch 126 when the cam 120 is rotated at a constant rotational speed. The detection range of the detection proximity switch 125 is activated earlier than the recess detection proximity switch 126 by the time t ₁ for the rotary table 14 to move the length L ₁ of the first recess 133, and rear cam length
The operation ends later by the time t ₂ during which the rotary table 14 moves through L ₂ .

Therefore, at the rising edge of the detection signal of the cam detection proximity switch 125, the counter 135, which counts the pulse signal of the recess detection proximity switch 126, can be easily set prior to counting. Detection proximity switch 12
5 detects the cam 120, the recess detection proximity switch 126 detects the recess 133 or the protrusion 134.
If the position detector is configured to count the recesses 133 provided in the cam 120, it becomes possible to always reset the counter before counting the recesses 133 provided in the cam 120 using the recess detecting proximity switch 126.
Even if the counter 135 malfunctions due to noise or the like in a rotating part where 0d to c is not present, it can be prevented from having an adverse effect when actually counting the concave portions 133, and the position control of the deceleration and stop of the rotary table 14 can be prevented. can be made even more reliable.

Furthermore, this hydraulic circuit is divided into a directional control valve 139 and a flow rate control valve 140, as shown in FIG. This flow control valve 140 is connected to the pulse motor 1 as shown in FIG.
The valve is of a type in which a nut shaft 143 moves back and forth by a ball screw 142 rotated by a hydraulic motor 101 to directly drive a valve spool 144.
The discharge flow rate can be controlled. The flow rate control valve 140 transmits a pulsed output signal detected by the recess detection proximity switch 126 to the counter 13.
5, and according to this count value, the flow control valve 1 which is pre-programmed by the controller 136
The opening degree and opening/closing speed of the 40 valve spools 144 can be directly controlled.
The valve opening degree of the flow rate control valve 140 is sequentially reduced in response to detection of a recess 133 provided in a cam 120 fixed to the cam 120.

[Problems to be Solved by the Invention] As described above, the concave and convex portions are detected by the concavity detecting proximity switch 126, and by accurately detecting the position of the rotary table 14, the rotation speed of the rotary table 14 is controlled. In the control method for decelerating and stopping 14, it is preferable to reduce the pitch P of the uneven portion in order to improve the accuracy of the stopping position. Further, in order to accurately detect the concavo-convex portion provided at a small pitch P by the concavity detection proximity switch 126, it is necessary to provide the concavity detection proximity switch 126 as close as possible to the surface of the cam 120.

However, in the case of a large machine such as the rotary die casting machine in this example, which has a rotary table 14 with an outer diameter of about 6 m and is equipped with a plurality of mold opening/closing units 29 each weighing several tens of tons, The limit of the gap l between the cam 120 and the proximity switch 126 for detecting recesses shown in the figure is 1 mm, and the pitch P of the recesses and recesses is approximately 10 mm (the protrusions 134 and the recesses 133
The maximum width of each is approximately 5 mm).

This is because the diameter of the bearing that supports the rotary table 14 is 1 m, but the dimensional accuracy of the bearing is generally about 0.1 mm to 0.3 mm, and one piece rotates the about 30-ton to 50-ton opening/closing unit 29. table 1
Even if the recess detection proximity switch 126 is moved closer to the cam 120 due to reasons such as distortion of approximately 0.1 mm to 0.2 mm occurring in the rotary table 14 when it is mounted on or removed from the cam 120, the gap must be at least approximately 1 mm. will require
Furthermore, in the case of a proximity switch that is generally easily available, if the pitch P of the concave and convex portion is set to approximately 10 mm or less as the detection discrimination width, one convex portion 134 is used as the detection discrimination width for the proximity switch 1 for detecting concave portions.
26, and when the recess 133 passes immediately before the recess detection proximity switch 126, the recess detection proximity switch 126 detects the next protrusion 34, making it impossible to detect the recess 133. It is from.

Considering the installation, adjustment, maintenance, etc. of the position detection means composed of the cam 120 and the proximity switch, the pitch P of the recess 133 is approximately 15
The limit is around mm, which makes it difficult to detect the position of the rotary table 14 in detail.
It was not possible to improve accuracy.

Furthermore, since the above detection method detects the position using a pulse signal from the proximity switch, the count value is memorized and retained in order to reset the pulse counter based on the reference position of the rotary table 14 and know the current position of the rotary table. It was necessary to take precautions such as keeping the

Furthermore, when the distance between the cam 120 and the proximity switch changes due to distortion in the rotary table 14, and the distance between the cam 120 and the proximity switch becomes greater, the recess detection proximity switch 126 detects the protrusion 134. This has the drawback that the timing of outputting the signal is delayed, making it difficult to accurately detect the position of the rotary table 14.

[Means for solving the problem] A plurality of mold opening/closing units each holding a pair of molds are disposed at appropriate positions in the circumferential direction on the outer periphery of a rotary table, and the rotation of the rotary table is intermittently stopped. For detecting rotation following the rotation of the rotary table when controlling the rotary table drive of a rotary die-casting machine configured to allow different processes to be performed simultaneously at each work station installed at the stop position of each mold opening/closing unit. A rotating shaft is provided, and the rotation of the detecting rotating shaft is detected by a rotation angle detector, and while the detecting rotating shaft makes one rotation, a continuous output is output in proportion to the rotation angle of the detecting rotating shaft. The rotary table is driven and controlled while detecting the rotation angle of the rotary table using a rotation angle detector that increases the signal, and each work station is arranged at equal intervals and one revolution of the rotation axis for detection is This corresponds to the amount of rotation of one station on the rotary table, and the rotary table is decelerated to a stop as the output of the rotation angle detector increases, so that the rotation is stopped while the output signal of the rotation angle detector is increasing. Make the table stop.

[Function] The present invention uses a rotation angle detector that is equipped with a rotation shaft that follows the rotation of the rotation table and continuously increases the output signal in proportion to the rotation angle, so the amount of rotation of the rotation table can be measured as a continuous value. It is possible to accurately detect the amount of rotation of the rotary table, and it becomes easy to improve the accuracy of braking and stopping control.
Furthermore, since the rotation angle detection output simply increases as the rotary table rotates, the position of the rotary table can be accurately detected based on the value of the output signal, making it easy to control the drive of the rotary table. I can do it.

Furthermore, if the work stations are equally spaced and the amount of rotation between one rotation of the detection rotation axis and one station of the rotary table is the same, the same operation is always required when moving the mold opening/closing unit between each station. The rotary table can be driven, decelerated and stopped according to the procedure, and the drive control of the rotary table can be made easier.

If the rotary table is decelerated to a stop while the output of the rotation angle detector is increasing, the operating procedure for decelerating and stopping the rotary table can be made simpler and easier.

[Embodiment] As shown in FIG. 1, a device according to an embodiment of the present invention includes a first gear 151 for transmission on the shaft of a hydraulic motor 101 that rotates a gear 20 that is integrally provided to a rotary table 14. a second transmission gear 152 that meshes with the first transmission gear 151 and rotates the detection rotation shaft 153; and a rotation angle detector 150 that detects the rotation angle of the detection rotation shaft 153. is provided, thereby detecting the rotating shaft 153.
The rotation angle detector 150 is configured to rotate with the rotation of the rotary table 14 by a second detection gear 152 serving as a rotating member, and detects the amount of rotation of the rotary table based on the rotation angle of the detection rotation shaft 153. A position determination device 154 is also provided for receiving the output signal.

The rotation angle detector 150 is connected to the rotation shaft 15.
3 rotates, the output signal value is increased in order to increase the output voltage, and when the rotating shaft 153 rotates once, the output voltage is returned to the original value, and the output is increased in proportion to the increase in the rotation angle. The output signal of this rotation angle detector 150 is sent to a position determination device 154, and the position determination device 154 is a detector that can repeatedly perform the rotation angle detector 150 (see FIG. 2). The rotation angle of the rotary table 14 is detected based on the magnitude of the rotation table 14, and a determination signal is sent to the controller 136.

Based on the discrimination signal output from the position discrimination device 154, the controller 136 controls the flow rate control valve 14.
0, thereby controlling the rotational speed and stop position of the rotary table 14 in the same manner as in the prior art.

In this embodiment, as shown in FIG.
Since the station 2, the second station 3, and the third station 4 are spaced at 120° intervals, and the mold opening/closing unit provided on the rotary table 14 is also spaced at 120° intervals, when the rotary table 14 rotates once, A gear 20, a pinion 100, and an attached first transmission gear 151 for driving the rotary table 14 so that the detection rotary shaft 153 rotates three times,
The gear ratio of the second transmission gear 152 is determined, and the detection rotating shaft 153 is rotated once each time the mold opening/closing unit moves between each work station, and
The position determination device 154 uses a 12-bit analog-to-digital conversion circuit, and the output of the rotation angle detector 150 is divided into 4096 equal parts and digitized to detect the rotation angle of the rotation table 14 at an angle of approximately 0.03°. This makes it possible to obtain position detection that is several dozen times more precise than the conventional method in which the recess cut into the cam 120 is detected by the proximity switch 126, which had a pitch limit of about 15 mm. And so.

The embodiment of the present invention uses such a highly accurate position determination device 154, and sets a constant value S _o in the output voltage of the rotation angle detector 150 as the stop position of the rotary table 14, as shown in FIG. At the same time, an arbitrary detection position S _n (m=0, 1, 2, ..., n-1) is set at a voltage value lower than the output voltage set as the stop position, and when each detection position is detected, the rotation table 14
Sequentially reduce the speed of

That is, if the voltage value corresponding to each detection position is set in advance as a reference setting value, the position discriminating device 154 can be used as a reference setting value as shown in FIG.
4 converts the value of the output signal S of the rotation angle detector 150 into a 12-bit signal, reads it, and obtains the minimum reference setting value.
When the value of S ₀ and the output signal S of the rotation angle detector 150 match, the coincidence signal is outputted to the controller 136 as a discrimination signal, the reference setting value is changed to S ₁ , and the output signal from the rotation angle detector 150 is output. S is the reference setting value
When it matches S ₁ , it outputs a matching signal again and changes the reference setting value to S ₂ , which is repeated.The reference setting value S _o of the stop position and the rotation angle detector 15
If it outputs a signal that matches the output signal from 0, the position discriminator 154 stops its operation, and during this time the rotary table 14 rotates 1/3 to move the mold opening/closing unit between the work stations. The next rotation control of the rotary table 14 is performed in the same manner, and the casting work etc. at each work station can be continued.

In this way, the reference setting value S _o that becomes the stop position is set in the latter half of the output signal during the increase of the output signal S from the rotation angle detector 150, and the detection position setting values S ₀ , S ₁ , S ₂ , ..., S _o-1 are set as values that are smaller than S _o and increase sequentially, and the drive control of the rotary table 14 is performed while detecting and confirming the position of the rotary table 14 using these reference setting values. In this case, even if the output signal value of the rotation angle detector 150 when starting the rotary table 14 is a large value close to S _o , the reference setting value of the position determining device 154 is a small S _o . Therefore, it is possible to reliably prevent the position discrimination device 154 from malfunctioning to output a discrimination signal immediately after starting.

After the rotary table 14 is decelerated and stopped by the control of the hydraulic motor 101, the final stop position of the rotary table 14 is corrected and fixed by the taper recesses 104a to 104c and the knock pins 102 provided on the lower surface of the rotary table 14. Therefore, the rotary table 1 is adjusted based on the final position adjustment using the dowel pin 102.
Due to the error caused by the slight movement of the rotary table 14 and the back crash of the gear train, the position determining device 154 will detect the stopped position of the rotary table 14 when the rotary table 14 is started again.
54 may output a stop signal and make starting difficult, whereas in the embodiment of the present invention, the value of the output signal S of the rotation angle detector 150 changes to the reference set value S of the stop position immediately after starting. Even if it matches _o , the position discriminator 15
4, the reference setting value to be compared with the value of the output signal S is replaced with _S0 , which is a smaller value than the stop position value S _o , so the position determination device 154 is prevented from outputting a stop signal. It is something that

Conventionally, in order to prevent such malfunctions, it is common to use a timer to stop the position detection operation for the required amount of time after starting, thereby preventing the output of a stop signal immediately after starting. However, this method of using a timer to prevent malfunctions is such that when changing the rotational speed of the rotary table 14, especially when increasing the rotational speed, the timer prevents deceleration within the time regulated by the timer. There are cases where the rotary table 14 rotates to a predetermined position where control, etc. should be performed, and in this case, the timer setting time must also be changed, which has the drawback of making the changing operation complicated.

Further, in the embodiment of the present invention, S _o is sequentially increased from the reference setting value S ₀ , and the reference setting value S _o that determines the stop position is set in the middle of the increase in the output signal S of the rotation angle detector 150 and the output signal is The inflection point of the output was avoided while keeping the output in the latter half of the range. That is, even though the rotation angle of the rotary table 14 is extremely small, the output signal of the rotation angle detector 150 changes greatly, and it is difficult to accurately detect the position due to mechanical errors caused by backlash of the gear train. The system decelerates and stops by detecting locations other than the inflection point. Therefore, it is possible to perform highly accurate rotation control, and to make it easy to create a control program by sequentially increasing the reference set value.

Note that since the rotation angle detector 150 outputs an output signal value that matches the minimum reference setting value _S0 due to the inflection point in the output signal S of the rotation angle detector 150 after the rotation table 14 is started, the minimum reference setting The amount of control change in the flow rate control valve ₁₄₀ due to the coincidence signal from the position discrimination device 154 based on the value S 0 is set to zero, and the discrimination signal that is a coincidence signal with this minimum reference set value S ₀ may not be used for deceleration control. preferable.

Moreover, the reference set values S ₁ to S _o are not limited to the case where they are set at equal intervals, and the rotation speed of the rotary table 14 is high when detecting the vicinity of the deceleration start position, and the rotation speed of the rotary table 14 is high just before stopping. Because of this, the interval near the deceleration start position may be set wider than the interval near the stop position, and the deceleration and stop may be controlled while finely detecting the position just before stopping.

[Effects of the Invention] The present invention provides a detection rotary shaft that rotates in conjunction with the rotary table through a gear from the drive shaft of a hydraulic motor that drives the rotary table, and rotates according to the rotation angle of the detection rotary shaft. Since the position of the table is detected, measurement errors due to distortion of the rotary table that occur when transferring the mold opening/closing unit to the rotary table are reduced, and the output is increased in proportion to the rotation angle of the detection rotary shaft. Since it uses a rotation angle detector that outputs a continuous output signal, it is possible to detect the position of the rotary table with extremely high precision, and
Since the output signal of the rotation angle detector is designed to simply increase within a certain range, the position of the rotary table can be easily confirmed by the absolute value of the output signal of the rotation angle detector, and the rotation table can be driven by braking, stopping, etc. Control can be performed accurately and easily.

[Brief explanation of drawings]

Figure 1 is a diagram showing the hydraulic circuit of the hydraulic motor and the position detection mechanism of the rotary table in the present invention, Figure 2 is a diagram showing the output of the rotation angle detector, and Figure 3 is a diagram showing the output of the rotation angle detector.
The figure is a flowchart showing the operation of the position discrimination device, Figure 4 is a diagram showing an example of setting the reference setting value as the detection position, Figure 5 is a plan view showing the entire rotary die casting machine, and Figure 6 is A vertical cross-sectional view along the center line of the first station of the rotary die-casting machine, and FIG. 7 is a plan view of the rotary table.
Fig. 8 is a side view of the rotary table of the rotary die-casting machine, Fig. 9 is a bottom view of the rotary table, Fig. 10 is a diagram showing an example of mounting a conventional position detection means, and Fig. 11 is a developed view of the cam of the position detection means. and the first
Fig. 2 is a diagram showing a position pulse signal emitted by a conventional position detection means, Fig. 13 is a graph showing changes in valve opening degree based on the position pulse signal, Fig. 14 is a conventional drive hydraulic circuit diagram, and Fig. 15 FIG. 2 is a diagram showing flow control valves used in the conventional art and in the present invention. 5=base platen, 14=rotary table, 2
0=gear, 100=pinion, 101=hydraulic motor, 102=knock pin, 109=hydraulic pressure supply source,
122=Bracket, 123=Bracket for proximity switch, 125=Proximity switch for cam detection, 1
26=first recess detection proximity switch, 127=second recess detection proximity switch, 128=third recess detection proximity switch, 133=recess, 134=protrusion, 135=counter, 136=controller,
138=Signal synthesis circuit, 139=Directional switching valve, 1
40=Flow rate control valve, 141, 142, 143=Rear end edge of recess, 150=Rotation angle detector, 151=
First transmission gear, 152 = Second transmission gear, 15
3=detection rotation axis, 154=position discrimination device.

Claims (1)

[Scope of Claims] 1. A plurality of mold opening/closing units each holding a pair of molds are disposed at appropriate positions in the circumferential direction on the outer periphery of a rotary table, and the rotary table is intermittently stopped from rotating to open and close each mold. In a rotary table drive control method for a rotary die-casting machine configured to allow work in different processes to be performed simultaneously at each work station provided at a stop position of an opening/closing unit, the rotary table rotates as the drive-controlled rotary table rotates. A member is provided, a rotation shaft for detection is attached to the rotation member, and a rotation angle detector is provided to detect the rotation angle of the rotation shaft for detection, and the rotation angle detector is configured such that the rotation shaft for detection is one. A rotation angle detector that continuously increases the output signal in accordance with the rotation angle of the rotation axis during rotation is used to detect the rotation angle of the rotation table based on the amount of rotation of the rotation axis for detection and stop the rotation table by braking. A drive control method for a rotary table of a rotary die-casting machine, characterized by performing the following steps. 2 The intervals between the plurality of mold opening/closing units arranged on the rotary table and the intervals between each work station are set at equal intervals, and the gears are set so that when the rotary table rotates between one station, the rotation axis for detection rotates once. 2. The rotary table drive control method for a rotary die-casting machine according to claim 1, further comprising determining a ratio and operating a rotation angle detector accordingly. 3. Claims characterized in that the rotational speed of the rotary table is reduced as the output signal of the rotation angle detector increases, and the stop position of the rotary table is located in the latter half of the output signal of the rotation angle detector. A rotary table drive control method for a rotary die-casting machine according to item 1 or 2.