JP2588514B2 - How to remove residual pressure from core cylinder hydraulic circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a method for releasing residual pressure in a hydraulic circuit of a core cylinder provided in a die apparatus such as a die casting machine. The present invention relates to a method for removing residual pressure in a core cylinder hydraulic circuit for preventing oil spillage and improving operability when attaching and detaching a slave cylinder.

[Conventional technology]

2. Description of the Related Art Conventionally, in a die apparatus of a die casting machine, a joint circuit capable of one-touch operation has been used for a hydraulic circuit of a core cylinder in order to facilitate attachment and detachment of piping such as a high-pressure hose at the time of mold replacement. FIG. 5 shows a configuration example of the joint pipe. In FIG. 5, reference numeral 10 denotes a female joint pipe, 12 denotes a male joint pipe, and these joint pipes 10, 12 are configured to be fitted and inserted into each other. Accordingly, a fitting ball 14 is provided at the distal end of the female joint pipe 10 and a sleeve 18 that elastically moves forward and backward by the action of the spring 16 is provided on the outer circumference thereof, whereas the sleeve 18 is elastically advanced and retracted by the action of the spring 16. Is provided with a circumferential groove 20 for fitting with the fitting ball 14. The female joint pipe 10 and the male joint pipe 12
An O-ring 22 is appropriately provided at the fitting portion of the above to enhance the sealing performance. Further, valve bodies 24 and 26 are provided at the openings of the female joint pipe 10 and the male joint pipe 12 opposite to each other.
Numerals 4 and 26 are attached to the inner peripheral surfaces of the joint pipes 10 and 12, respectively, by springs 28 and 30 having one ends fixed so as to be able to reciprocate elastically in the pipe axis direction. The distal ends of these valve bodies 24 and 26 are provided with tapered surfaces 32 and 34 whose diameters can be gradually increased, while the open ends of the joint pipes 10 and 12 are connected to the distal ends of the valve bodies 24 and 26. Tapered surfaces 36, 38 of progressively smaller diameter are provided for engagement. Therefore, as shown in the figure, when the female joint pipe 10 and the male joint pipe 12 are fitted, the opposing valve bodies 24, 26 abut on their distal end surfaces, and the elasticity of the springs 28, 30 respectively. Retreat and oppose each valve 2
4,26 taper surface 32,34 and each joint pipe 10,12 taper surface 36,38
Are separated from each other to form an oil passage interlocking with each other. Also,
When the female joint pipe 10 and the male joint pipe 12 are cut off, each valve element 24, 26 advances to the open end side under the elasticity of the springs 28, 30, respectively, and each valve element 24, 26 Tapered surface 32,34 and each fitting tube 10,1
The second tapered surfaces 36 and 38 are in contact with each other to perform sealing.

Therefore, by using the joint pipe in this way, it is possible to easily attach and detach a required hydraulic pipe from the hydraulic circuit of the core cylinder.

[Problems to be solved by the invention]

However, from the hydraulic circuit of the core cylinder provided with the joint pipe having the above-described configuration, when a required hydraulic pipe is attached / detached by the joint pipe, for example, when the joint pipe is disconnected, the residual pressure of the hydraulic circuit is sealed. Acts on each valve element of the pipe. For this reason, when reconnecting the joint pipe, it cannot be easily connected only by manual operation. The pressure has to be removed.

Further, if there is a residual pressure in the hydraulic circuit, oil is ejected for a short time having a movement stroke until the valve pair is in a sealed state. This oil squirt extends to 5 to 10 cc. For example, if the mold change is performed once or twice a day, two joint pipes are used for one core cylinder. 20c per attachment / detachment for one child cylinder
c, If there are three core cylinders, it will be 60 cc, which will result in oil leakage of about 3000 cc or more in one month.

Accordingly, an object of the present invention is to operate a solenoid directional switching valve provided in a hydraulic circuit in a die apparatus such as a die casting machine when a hydraulic pipe of a core cylinder is detached from a required hydraulic circuit when the die is replaced. Another object of the present invention is to provide a method for removing residual pressure in a core cylinder hydraulic circuit, which can remove residual pressure in a hydraulic circuit, prevent oil leakage when attaching and detaching a joint pipe, and improve operability.

[Means for solving the problem]

A residual pressure removing method for a core cylinder hydraulic circuit according to the present invention includes a core cylinder and a direction switching valve for performing hydraulic control of the core cylinder, and a joint pipe capable of automatically sealing the core cylinder. A method for detachably connecting to a die apparatus such as a die casting machine and operating the directional control valve at the time of stoppage after the operation of the hydraulic pump to remove residual pressure in the hydraulic circuit of the core cylinder. At the time of stop, the relay contact which detects and operates this state is first turned on for a certain time (T1) to delay the start of operation of the core cylinder for a certain time (T1), and thereafter, the delayed fixed time (T1) ) After a lapse of time, the relay contact that excites the solenoid to move the core cylinder to the return side is turned ON for a certain time (T2), and then, after the lapse of a certain time (T3), the core cylinder is moved to the entry side. The relay contact that excites the solenoid is turned on for a certain period of time (T4), and then the relay contact that excites the solenoid is turned on again for a certain time (T2) immediately after the lapse of a certain time (T5). The operation cycle consisting of the predetermined time (T2) to (T5) until the ON operation is performed is repeatedly performed several times sequentially.

[Action]

According to the residual pressure removing method of the core cylinder hydraulic circuit according to the present invention, in a mold apparatus such as a die casting machine, when the core cylinder is detached from the hydraulic circuit at the time of mold replacement,
The residual pressure in the hydraulic circuit is enabled by switching the direction switching valve that controls the core cylinder to the core entry side and the core return side at predetermined timings when the hydraulic pump is stopped after operation. Can be removed.
In particular, by repeating the switching operation cycle a plurality of times, not only the residual pressure in the hydraulic circuit can be removed as quickly as possible, but also these switching operations are performed by a plurality of core cylinders by a programmable sequence controller. Can be operated simultaneously and sequentially.

〔Example〕

Next, the method for removing the residual pressure of the core cylinder hydraulic circuit according to the present invention will be described in detail with reference to an example of the configuration of a system for implementing the method.

FIG. 1 is a system diagram showing one embodiment of a core cylinder hydraulic circuit for implementing the residual pressure removing method of the present invention. In FIG. 1, reference numeral 40 is a core cylinder, 42 and 44 are joint pipes, 4
6 indicates a direction switching valve, 48 indicates a check valve, and 50 indicates a hydraulic pump. Note that the joint pipes 42 and 44 used in this embodiment are one-touch operated joint pipes shown in FIG. 5, respectively. The directional control valve 46 is provided with a solenoid CFSOL for operating the core cylinder 40 on the entry side and a solenoid CBSOL for operating the return side, and the piston rod of the core cylinder 40 is protruded by the bias of the solenoid CFSOL. In the direction in which the piston rod of the core cylinder 40 is retracted by the bias of the solenoid CBSOL.

FIG. 2 shows a control circuit of the direction switching valve 46 in the hydraulic circuit of the core cylinder 40 configured as shown in FIG. In FIG. 2, the direction switching valves of the hydraulic circuits provided for the plurality of core cylinders are configured to be programmably controlled by the programmable sequence controller PC-O. In addition,
CB indicates a circuit breaker. Note that each relay contact 1CFS, 1CB of the programmable sequence controller PC-O
In S and the like, “Y ***” such as “Y350” means an output of the programmable sequence controller.

FIG. 3 shows an embodiment of a preset relay ladder circuit in the aforementioned programmable sequence controller PC-O. The operation of the relay ladder circuit shown in FIG. 3 will now be described with reference to a time chart of the operation characteristics shown in FIG. 4 for an embodiment of the residual pressure removing method according to the present invention. In FIG. 3, the line No.
Is a circuit for confirming that the hydraulic pump has stopped after operation, and a contact HPDR indicates a pump operation signal contact. Therefore, when the pump operation confirmation relay CPDR operates, the line N
o. The CPDR contact turns ON and is self-held. AL
The contact is a contact when the hydraulic pump is operated. When the hydraulic pump stops (AL contact OFF), the timer CPDR operates and turns on the CPDT contact of the line No. after the timer set time T ₁ (delay time) has elapsed. It operates (see FIG. 4). Then, the timer CFT1 is operated, the CFT1 contact of the line No. is turned on, the output relay 1CBS is turned on, and the solenoid CBSOL is excited so that the core cylinder is operated backward (see FIG. 4). After the set time T ₂ of the timer CFT1 has elapsed, CFT1 contact line No. is operated ON, the timer CBST1 operates. After the set time T ₃ of the timer CBST1 has elapsed, CBST1 contact line No. is operated ON, the timer CBT1 operates ON. When this timer CBT1 is input, the contact CBT1 of the line No. is turned on, the internal relay 1CFS is turned on, and the solenoid CFSOL is operated to move the core cylinder to the entry side.
(See FIG. 4). Set time of this timer CBT1
After the T ₄ has elapsed, CBT1 contact line No. is operated ON,
The core timer delay timer CFST1 operates. This timer CFS
After the set time T ₅ of the T1 has elapsed, CFST1 timer contact line No. is operated ON, the residual pressure removal cycle is repeated.

Here, the counter CC of the line number accumulates the number of times for each residual pressure removal cycle, and when the set number of times is reached, the CC contact of the line number is turned off to complete the residual pressure removal control. The line Nos. And are for a plurality of core cylinders.

Thus, according to the present invention, as shown in FIG.
In the hydraulic circuit of the core cylinder, when the hydraulic pump is stopped after the operation, the directional control valve is operated at a fixed timing to the core return side and the core entrance side in a plurality of cycles, respectively, so that the hydraulic circuit Residual pressure can be effectively removed.

The sequence control for the residual pressure removal control described above shows one embodiment of the method of the present invention, and the present invention is not limited to the above-described embodiment, and may be variously controlled without departing from the spirit of the present invention. It is needless to say that the design can be changed.

〔The invention's effect〕

As is apparent from the above-described embodiment, according to the present invention, in a mold apparatus such as a die-casting machine, a joint having an automatic sealing mechanism in which a required hydraulic pipe in a hydraulic circuit of a core cylinder is provided in advance when replacing a mold. In the case of attaching and detaching by a pipe, the direction switching valves for controlling the core cylinder provided in the hydraulic circuit are operated at predetermined timings with the piston rods on the core returning side and the core entering side, respectively, so that the hydraulic circuit has Effectively removes residual pressure when stopping the hydraulic pump after operation, prevents oil leakage in the state of jetting due to residual pressure when disconnecting the joint pipe, and smoothly operates the valve body when connecting the joint pipe. The removal of residual pressure of these core cylinders can also be performed programmably using a programmable sequence controller. Therefore, the effect contributing to automation of the mold changing operation is extremely large.

[Brief description of the drawings]

FIG. 1 is a main part system diagram of a core cylinder hydraulic circuit for implementing a residual pressure removing method according to the present invention, and FIG. 2 is a sequence control circuit for operating the core cylinder control directional switching valve shown in FIG. FIG. 3 is a diagram showing a relay ladder circuit set in a programmable sequence controller for programmably controlling the sequence control circuit shown in FIG. 2, and FIG. 4 is a time chart showing operating characteristics of the directional control valve shown in FIG. FIG. 5 is a sectional view of a joint pipe used in the hydraulic circuit of the core cylinder. 10 ... female fitting pipe, 12 ... male fitting pipe 14 ... fitting ball, 16 ... spring 18 ... sleeve, 20 ... circumferential groove 22 ... O-ring, 24, 26 ... valve Body 28, 30 Spring, 32, 34 Tapered surface (valve side) 36, 38 Tapered surface (joint tube side) 40 Core core, 42, 44 Joint tube 46 Direction change Valve, 48 Check valve 50 Hydraulic pump CFSOL Core insert solenoid CBSOL Core return solenoid CPDR Pump operation confirmation relay CPDT Timer (T ₁ ) CFT1 Timer (T ₂ ) CBST1 …… Timer (T ₃ ) CBT1 …… Timer (T ₄ ) CBST1 …… Timer (T ₅ ) CC …… Counter

Claims (1)

(57) [Claims] 1. A core cylinder and a direction switching valve for controlling a hydraulic pressure of the core cylinder. The core cylinder is detachably attached to a die apparatus such as a die casting machine through a joint pipe capable of automatically sealing. In the method for removing the residual pressure of the hydraulic circuit of the core cylinder by operating the directional switching valve when the hydraulic pump is stopped after the operation of the hydraulic pump, this state is first detected when the hydraulic pump is stopped after the operation. The activated relay contact is turned ON for a certain time (T1) to delay the start of the operation of the core cylinder for a certain time (T1), and then, after the delayed fixed time (T1) has elapsed, the core cylinder is moved to the return side. A relay that excites the solenoid to excite the solenoid so that it turns ON for a certain time (T2), and then energizes the solenoid so that the core cylinder moves to the entry side after the elapse of a certain time (T3) The point until the point is turned on for a fixed time (T4) and then immediately after the fixed time (T5) elapses, the relay contact for energizing the solenoid so as to return the core cylinder to the return side again for a fixed time (T2) is turned on. A method for removing residual pressure in a core cylinder hydraulic circuit, comprising repeating an operation cycle consisting of a fixed time (T2) to (T5) several times sequentially.