JPH0952267A - Dual rod hydraulic cylinder device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give stable mold clamping force to a mold by equally setting a channel distance from a return port to the rear pressure chambers of paired pistons. SOLUTION: When clamping hydraulic cylinder is clamped by high pressure, the distances of channels 81, 61, 62a from a return port P2 to a pressure chamber 56b are equally set to the distances of channels 81, 61, 62b from a return port P2 to another pressure chamber. Accordingly, when hydraulic oil is press injected to the port P2 in the cylinder, a pair of piston rods PR1 , PR2 are operated in the compressing direction by the same amount at the same timing. Thus, the moving mold of the mold is strongly brought into pressure contact with the stationary mold and the mold is clamped.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hydraulic cylinder device for applying a mold clamping force to a mold.

[0002]

2. Description of the Related Art Conventionally, a composite type injection molding apparatus has a mold clamping device for opening and closing a mold for injection molding, and an injection section for filling the mold with a material such as synthetic resin melted and heated. It is configured integrally with the unit. In such an injection molding apparatus, for example, when a mold clamping force is applied to maintain a closed state, the upper mold is pressed against the lower mold as stably as possible. It is desirable to apply an even force to.

However, if a plurality of ordinary hydraulic cylinders are used to realize this, a lot of space is required to accommodate the plurality of hydraulic cylinders, resulting in an increase in size of the apparatus.

[0004]

SUMMARY OF THE INVENTION The present invention is based on the above-mentioned consciousness of the problem in the conventional injection molding apparatus and is capable of giving a stable mold clamping force to the mold and suppressing the increase of the accommodation space of the hydraulic cylinder as much as possible. An object is to provide a rod hydraulic cylinder device.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a pair of piston cylinder chambers formed in parallel with each other in a single cylinder body; A pair of piston bodies that respectively form pressure chambers; a pair of piston rods that are respectively fixed to the pair of piston bodies and are not coupled to each other;
A going port and a returning port, which are opened in the cylinder body and communicate with one and the other of the pressure chambers in front of and behind the pair of piston bodies, respectively; flow path distances from this going port to the front pressure chambers of the pair of piston bodies, respectively. Are set to be equal; and flow path distances from the return port to the rear pressure chambers of the pair of piston bodies are set to be equal to each other.

A pair of outgoing ports are formed directly in the cylinder body so as to correspond to the pair of piston bodies, and one return port opens one in the cylinder body, and a pair of pressure chambers are provided through the passage in the cylinder body. Can be connected to.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to illustrated embodiments. 2 is a plan view showing a base and a slide table of a slide molding apparatus using a dual rod hydraulic cylinder device according to the present invention, and FIG. 1 is a side sectional view taken along line II of FIG. 2 (however, an injection unit is shown). Is not shown in FIG. 2, but is shown in FIG. 1).

In FIG. 1, the slide molding apparatus 10 is
A horizontally long base 11 (see FIG. 2), a slide table 12 that reciprocates linearly on the base 11, and two molds 13a and 13b (see FIG. 4) provided on the slide table 12. It has one mold opening / closing mechanism 15 for opening and closing the molds 13a and 13b at a specific position. The slide molding device 10 further includes one injection unit 16 for injecting a resin material into the molds 13a and 13b closed by the mold opening / closing mechanism 15 and clamped by the clamp mechanism 17a or 17b, and the slide table 12
It has two clamp mechanisms 17a and 17b, which are provided correspondingly to the respective dies 13a and 13b, and which apply a clamping force to the respective dies 13a and 13b. The molds 13a and 13b each include a moving mold 36 and a fixed mold 37.

The slide table 12 slides in the left-right direction in FIG. 2 by engaging a slide rail 19 provided along the longitudinal direction of the base 11 with a guide groove 14 formed along the same direction. It is movably supported. As shown in FIG. 1, the slide rail 19 has a cross section T having a wide top portion.
The slide table 12 is formed in a letter shape, and the T-shaped portion is engaged with the corresponding step portion of the guide groove 14 to prevent the slide table 12 from coming off.

As shown in FIG. 2, on the right side of the base 11,
A table drive hydraulic cylinder 20 is provided. In this table-driving hydraulic cylinder 20, the tip end portion of the piston rod 20 a is attached to the right end portion of the slide table 12. Therefore, when the table driving hydraulic cylinder 20 operates based on a signal from a control unit (not shown) such as a computer to expand / contract the piston rod 20a, the slide table 12 moves on the base 11
The two dies 13a and 13b move straight in a reciprocating direction.

The slide table 12 also includes a mold 13.
It has mounting parts 12a and 12b on which a and 13b are mounted. The mounting portions 12a and 12b are the mold 13 to be mounted.
In order to separate a and 13b by a predetermined distance, they are provided in the moving direction of the slide table 12 by a predetermined distance. The slide table 12 includes a mold 13a and an injection unit 1
6, a first supply position where the melted molding material can be supplied from the injection unit 16 and a mold 13b located below the injection unit 16 and the melted molding material can be supplied from the injection unit 16. It is moved to the second supply position.

In the direction orthogonal to the moving direction of the slide table 12, the moving mold 13a or 13b is
A pair of die clamps 21a and 21b, which is sandwiched and held at a position corresponding to the upper injection unit 16, is provided so as to face each other. The die clamps 21a and 21b have the same configuration, and are brought into contact with the lower step portion 22 of the fixed die 37 of the die 13a or 13b from above to make the die 13
Each has a clamp claw 23 for restricting the movement of a or 13b.

The die clamps 21a and 21b are respectively
A hydraulic cylinder 25 that operates based on a signal from a control unit (not shown) is configured to move forward and backward in the vertical direction in FIG. 2 (the horizontal direction in FIG. 1) at the same timing. The clamp claw 23 is moved by the operation of the hydraulic cylinder 25 so that the mounting portion 1
While advancing toward the die 13a or 13b on the 2a, it rotates downward and presses the lower step portion 22 from above. Further, when retracting from the placing portion 12a, the lower step portion 22 is released by rotating upward. With such a configuration, the die clamps 21a and 21b are attached to the slide table 12
When moving the mold 13a or 13b held above, the clamp claw 23 is retracted from above the lower step portion 22 to release the mold 13a or 13b, and the mold 13b or 13b is released.
When a is fixed at a position below the injection unit 16, the clamp claw 23 can be advanced onto the lower step portion 22 to press the mold 13a or 13b.

As shown in FIGS. 1 to 5, the mounting portion 12
The clamp mechanism 17a is provided corresponding to a, and the clamp mechanism 17b is provided corresponding to the mounting portion 12b. The clamp mechanism 17a includes clamp hydraulic cylinders 27 and 28, 29 and 30 that are opposed to each other in a direction orthogonal to the direction of linear movement of the slide table 12. Further, the clamp mechanism 17b has clamping hydraulic cylinders 31 and 32, and 33 and 34 that oppose each other in a direction orthogonal to the direction of linear movement of the slide table 12. Between the clamping hydraulic cylinders 27 and 29, and between 28 and 30, when the mold 13a mounted on the mounting portion 12a is located directly below the injection unit 16, the clamp claws 23 of the die clamps 21a and 21b are provided. Are arranged so as to approach the slide table 12 by a predetermined distance in the direction of straight movement of the table 12. Similarly, the clamp hydraulic cylinders 31 and 33, and 32 and 34 are also arranged at a predetermined distance in the direction of linear movement of the slide table 12.

Each of the clamping hydraulic cylinders 27 to 34 has a pair of piston rods PR ₁ and PR ₂ provided in parallel with each other in a single cylinder body CB. The tips of the piston rods PR ₁ and PR ₂ of the clamping hydraulic cylinders 27 to 30 are fixed to the four corners of the mold clamping plate 35a that directly applies the mold clamping force to the mold 13a. The tip end portions of the piston rods PR ₁ and PR ₂ of the clamping hydraulic cylinders 31 to 34 are fixed to the four corners of the mold clamping plate 35b that directly applies the mold clamping force to the mold 13b.

The clamping hydraulic cylinders 27 to 30 and 31 to 34 which constitute the dual rod hydraulic cylinder device.
Are configured so that they are simultaneously driven to expand and contract by the same amount by a common hydraulic drive system. Since all of the clamp hydraulic cylinders 27 to 34 have the same structure, the clamp hydraulic cylinder 28 is represented by the structure shown in FIG.
This will be described with reference to FIG.

As shown in FIGS. 6 and 7, the hydraulic cylinder 28 for clamping has a pair of piston cylinder chambers 5 formed in parallel with each other inside a vertically elongated single cylinder body CB.
It has 6, 57. The clamp hydraulic cylinder 28 is also slidably fitted in the piston cylinder chamber 56, and has a piston body 59 that forms pressure chambers 56a and 56b in the front and rear thereof.
And a piston body 60 slidably fitted in the piston cylinder chamber 57 and forming pressure chambers 57a and 57b in front and rear thereof,
A pair of piston rods PR ₁ and P ₁ fixed to the pair of piston bodies 59 and 60, respectively, but not coupled to each other.
R ₂ and. The piston cylinder chamber 56 described above
The front means the lower part of the piston body 59 in FIG. 7, and the rear means the upper part of the piston body 59. The front of the piston cylinder chamber 57 means the lower part of the piston body 60 in the same figure, and the rear means the upper part of the piston body 60.

The hydraulic cylinder 28 for clamping has a going port P ₁ communicating with a pressure chamber 56a in front of the piston body 59, which is opened in the cylinder body CB, and a pressure chamber 5 in the rear.
It has a return port P ₂ communicating with 6b. The clamping hydraulic cylinder 28 further has a going port P ₃ opened to the cylinder body CB and communicating with a pressure chamber 57a in front of the piston body 60, and a return port P ₂ communicating with the pressure chamber 57b in the rear. ing. Outbound ports P ₁ and P
₃ is directly bored in the cylinder body CB so as to correspond to the pair of piston bodies 59 and 60, respectively. Further, the return port P ₂ communicating with the pressure chambers 56b and 57b is composed of one opening formed directly in the cylinder body CB. The single return port P ₂ is connected to the pair of pressure chambers 56b through the flow passages (passages) 81, 61, 76, 62a and the flow passages (passages) 81, 61, 76, 62b in the cylinder body CB. And 57b, respectively.

The distance of the flow path 80a from the going port P ₁ to the pressure chamber 56a in front of the piston body 59 and the distance of the flow path 80b from the going port P ₃ to the pressure chamber 57a in front of the piston body 60 are both a (see FIG. 10) are set equally. Also, the flow paths 81, 61, ₇ from the return port P ₂ to the pressure chamber 56b behind the piston body 59.
6, 62a distance and return port P ₂ to piston body 6
0, the flow paths 81, 61, 76 leading to the pressure chamber 57b behind,
The distances of 62b are set to be equal. The clamping hydraulic cylinders 27 to 34 have their mold clamping forces arbitrarily controlled by an electromagnetic proportional pressure reducing valve (not shown).

Counterbores for fitting O-rings (not shown) for sealing are formed in the outgoing ports P ₁ , P ₃ and the return port P ₂ , respectively. When fixed to the slide table 12, the O-ring is for connecting the flow path on the table 12 side and the ports P ₁ , P ₂ , P ₃ in an oil-tight manner. In addition, reference numerals 67 and 68 in FIG. 6 denote rod covers (plugs) that close the upper portion of the cylinder body CB, 75 denotes a head cover that closes the lower portion of the cylinder body CB, 69 denotes a rod seal, 70 denotes an O ring, and 73 denotes a piston seal. Is. Furthermore, FIG. 1 and FIG.
Reference numeral 90 is a port for supplying hydraulic oil to the clamp hydraulic cylinders 27 to 30 through the flow path in the slide table 12 and draining the hydraulic oil from the cylinders 27 to 30, and 91 is hydraulic oil. , Ports for supplying hydraulic fluid to the clamping hydraulic cylinders 31 to 34 through the flow path in the slide table 12 and draining from the cylinders 31 to 34.

The cylinder body CB integrally has, at its lower portion, an overhanging portion 63 for fixing the cylinder body to the slide table 12. The outgoing ports P ₁ and P ₃ and the return port P ₂ are directly bored in the overhanging portion 63 which is a part of the cylinder body CB. A parallel key 6 is provided below the outgoing ports P ₁ and P ₃ for positioning when the cylinder body is fixed to the slide table 12.
3a is provided. Reference numeral 58 in FIG. 6 is a screw hole used when fixing the cylinder body CB to the slide table 12, and reference numeral 90 is a seal member.

With the above structure, the hydraulic cylinder 28 for clamping, that is, the hydraulic cylinders 27 to 34 for clamping, receives hydraulic oil (pressure oil) from a hydraulic device (not shown) and is press-fitted into the ports P ₁ and P _3. Then, extension driving is performed by the same amount at the same timing (see FIG. 7). Further, when the hydraulic oil from the hydraulic device is press-fitted into the return port P ₂ , the clamping hydraulic cylinders 27 to 34 are driven in the contracting direction by the same amount at the same timing. The clamp mechanisms 17a and 17b are moved by the clamp hydraulic cylinders 27 to 34 operating in this way to the molded product take-out position shown by the two-dot chain line in FIG. 1 and the mold clamping position shown by the solid line in FIG. Reference numeral 18 in FIG. 5 is a pipe for temperature control of the molds 13a and 13b.

On the other hand, FIG. 3 shows the mold clamping plates 35a and 35a.
The state which looked at b from the back surface is shown. As shown in the figure,
The mold clamping plates 35a and 35b are each formed in a rectangular shape in plan view having the same shape as each other.
A nozzle opening 39a for inserting 6 is provided, and two fixing holes 40 are provided at four corners. This fixing hole 40 is
It is for inserting and fixing the tip ends of the piston rods PR ₁ , PR ₂ . Further, the mold clamping plates 35a and 35
b has fixed annular members 39 and 38 at the upper and lower portions of the nozzle port 39a, respectively, and a pair of notches 45 facing each other in the direction orthogonal to the direction of straight movement of the slide table 12 (the horizontal direction in FIG. 3). Have respectively. The notch 45 is used to bring the clamp claws 43 of the die clamps 41a and 41b that move up and down together with the injection unit 16 toward the ends of the movable mold 36 that overlaps the mold clamping plates 35a and 35b.

In FIG. 1, an elevating part 44 is an injection unit 16 and a pair of die clamps 4 forming a mold opening / closing mechanism 15.
1a and 41b are integrally movable up and down. The injection unit 16 has an injection nozzle 26 for injecting a melt-molded resin material into the mold 13a or 13b, an air blow 24, and a nozzle shutter 8. When the injection nozzle 26 descends toward the mold 13a or 13b held by the clamp mechanism 17a or 17b, it is connected to the nozzle port 48 of the mold 13a or 13b. The elevating unit 44 is operated by a hydraulic cylinder (not shown) that operates based on a signal from a control unit (not shown).
The mold 13a or 13b located at the first or second supply position is configured to be movable up and down to a lowered position where the molten molding material can be supplied, and a rising position where the movable mold 36 is lifted by the clamp claw 43. .

The die clamps 41a and 41b are respectively moved in the vertical direction in FIG. 3 (the horizontal direction in FIG. 1) by a hydraulic cylinder 42 which operates based on a signal from a control section (not shown).
It is configured to advance and retreat at the same timing. The die clamps 41a and 41b are provided so as to face each other in a direction orthogonal to the moving direction of the slide table 12, and the molds 13a and 13b are located directly below the injection unit 16.
The clamp claw 43 for lifting the moving die 36 of
Have each.

As shown in FIG. 12, the movable mold 36 and the fixed mold 37 constituting the mold 13a (or 13b) are composed of a plurality of lens molding upper molds 46 and a lower mold 47, and an injection unit 16.
A nozzle port 48 that receives the supply of the melt-molded resin material from the resin mold is formed, and a resin passage 50 that guides the melt-molded resin material supplied to the nozzle port 48 into a molding space 49 formed by the lens-molding upper mold 46 and the lower mold 47. . Reference numeral 51 in FIG. 12 is a gate, reference numeral 52 in FIG. 13 is a hopper, 53 is an injection screw in the injection nozzle 26, and 54 is a molten resin chamber.

The hydraulic cylinder (not shown) for driving the mold opening / closing mechanism 15 provided in the elevating part 44, the clamping hydraulic cylinders 27-34 for driving the clamp mechanisms 17a and 17b, and the slide table 12 described above are provided. The table-driving hydraulic cylinder 20 and the like for moving are connected to a hydraulic device (not shown), and are driven by the hydraulic device. The hydraulic system is sequentially controlled by the control unit (not shown) including a computer and the like.

In the slide molding apparatus, the molds 13a and 13b placed on the slide table 12 are independently cycled for mold clamping, mold opening and mold clamping, and the injection unit 16 is The cycle of nozzle connection, filling, nozzle separation, movement, and nozzle connection is repeated.

The above cycle will be described in detail. The slide table 12 of the slide forming apparatus in this embodiment.
Is as shown in FIG. 2 before the injection molding process. That is, the slide table 12 on which the molds are not placed on the placing portions 12a and 12b is moved to the right in FIG. 2, and the placing portion 12a is positioned at a position corresponding to the die clamps 21a and 21b. There is. In this state, the clamping hydraulic cylinders 27 to 3 below the mold clamping plate 35a.
The mold 13a is inserted into the space surrounded by 0, and the mold 13a is inserted into the space surrounded by the clamping hydraulic cylinders 31 to 34 below the mold clamping plate 35b.
b is mounted on the mounting parts 12a and 12b, respectively. FIG.
Although not shown in the drawing, the hydraulic cylinders 27-34 for clamping
Mold clamping plates 35a and 35b are fixed to the respective tip portions.

In the initial state, the dies 13a and 13b are restricted from moving by the relatively light actuation of the clamp mechanisms 17a and 17b, and the dies 13a are further
With the clamp claws 23 of the die clamps 21a and 21b positioned below the injection unit 16, the lower step portion 22 is formed.
And is fixed on the mounting portion 12a. From this initial state, the injection molding process is started by operating a predetermined switch.

Next, this injection molding process will be described with reference to the time chart of FIG. 14 showing an operation example of the present slide molding apparatus.

On the mold 13a side, first, the molded product molded in the previous step is taken out of the mold 13a, a hydraulic cylinder (not shown) is operated to lower the elevating part 44, and the clamping hydraulic cylinder 27 is used. It outputs a signal for retracting and operating ~ 30. Then, hydraulic oil from a hydraulic device (not shown) is supplied to the return port P ₂ of each of the clamping hydraulic cylinders 27 to 30 via the port 90, and the pressure ports 56 a and 57 b are supplied from the outgoing ports P ₁ and P _3. The hydraulic oil inside is drained and the hydraulic cylinders for clamping 27-3
0 is shortened by high pressure. In this case, the distance of the flow paths 81, 61, 76, 62a from the return port P ₂ to the pressure chamber 56b and the flow path 8 from the return port P ₂ to the pressure chamber 57b.
Since the distances 1, 61, 76 and 62b are set equal, the hydraulic cylinders 27 to 30 for clamping have the same piston rods PR ₁ and PR ₂ when hydraulic oil is press-fitted into the return port P _2. Operate the same amount in the contraction direction at the timing. As a result, the mold clamping plate 35a is strongly lowered, and the moving mold 36 of the mold 13a is moved to the fixed mold 3.
7 is strongly pressed and the mold is clamped.

Further, the nozzle shutter 8 is opened, the injection nozzle 26 is connected to the nozzle opening 39a of the mold clamping plate 35a, and the molten molding resin material is filled in the mold 13a. When the filling is completed, the injection nozzle 26 is raised with respect to the elevating part 44 and separated from the mold 13a, and the nozzle shutter 8
Close. Even after this, the hydraulic cylinders for clamping 27-3
Hold 0 to maintain the mold clamping force. Then, the molding condition on the computer is changed for the next mold 13b while the injection nozzle 26 is positioned above the mold 13a.
The molding conditions are a number of parameters such as the amount of resin, the moving speed of the injection screw 53 at the time of injecting the molten resin, and the pressure applied to the screw 55, and are stored in a storage device (not shown). Such a nozzle delay step can be shortened in time depending on molding conditions.

Further, the amount of resin under this molding condition is measured and stored in the injection unit 16. In order to prepare for the next injection, as shown in FIG. 13, the injection screw 53 in the injection nozzle 26 is rotated and retracted so that the hopper 5
It is a work of heating and melting the resin material from 2 and storing it in the molten resin chamber 54. The measured resin amount is the injection screw 53
It is detected by monitoring the position of.

Then, the die clamps 21a and 21b are retracted to release the lower step portion 22 of the mold 13a, and the elevating portion 44 that retracts the injection nozzle 26 is raised (retracted) to move the table driving hydraulic cylinder. 20 is extended to move the slide table 12 straight to the left in FIG. 5, and this time the mold 13b is positioned directly below the injection unit 16. The lower step 22 of the mold 13b is moved to the die clamp 21a,
The clamp claw 23 of 21b presses and fixes. During this time, the mold 13a located at the position below the injection unit 16 has the clamping hydraulic cylinders 27 to 30.
By the holding pressure by, the cooling is performed for a predetermined time while maintaining a predetermined mold clamping force. During this cooling process, the other mold 1
Processes such as injection for 3b are performed.

Further, after a lapse of a predetermined time required for cooling (after completion of cooling), the die clamps 21a and 21b are retracted to release the lower step portion 22 of the die 13b, and this time, the table driving hydraulic cylinder 20 is opened. The contraction operation is performed, the slide table 12 is moved to the right in FIG. 5, and the mold 13b is
The mold 13a is removed from the position below the injection nozzle 26 for cooling, and the mold 13a is positioned directly below the injection nozzle 26. Then, the elevating part 44 is attached to the die clamps 41a, 41b.
While moving backward, lower it. At this time, the pair of clamp claws 43 facing each other pass through the notches 45 facing each other in the mold clamping plate 35a downward, and then the die clamp 41a,
By the operation of 41b, they approach each other and come into contact with the lower part of the moving mold 36.

At this point, the clamp hydraulic cylinder 27
It outputs a signal for extending the .about.30. Then, hydraulic oil from a hydraulic device (not shown) is supplied to the going ports P ₁ and P ₃ of the clamping hydraulic cylinders 27 to ₃₀ via the port 90, and the return port P ₂
The hydraulic oils in the pressure chambers 56b and 57b are respectively drained from the hydraulic pressure cylinders 56b and 57b, and the clamping hydraulic cylinders 27 to 30 are extended to release the mold clamping force. In this case, the distance of the flow path 80a from the going port P ₁ to the pressure chamber 56a in front of the piston body 59, and the going port P ₃ to the piston body 60.
Is set to be equal to the distance of the flow path 80b to the pressure chamber 57a in front of the clamp hydraulic cylinders 27-.
When the hydraulic oil goes to each of the ports 30 and 30 and is press-fitted into the ports P ₁ and P ₃ , the piston rods 30 extend the piston rods PR ₁ and PR ₂ by the same amount at the same timing.

After that, the elevating part 44 is raised to move the mold 1
The moving mold 36 of 3a is lifted together with the mold clamping plate 35a to be separated from the fixed mold 37, the mold 13a is opened, and the molded product is taken out from this mold 13a. After this, the injection molding process is repeated from the beginning.

On the other hand, on the mold 13b side, the injection process is performed as follows. That is, the mold 13b is removed from the position directly below the injection unit 16 and is cooled while the process of taking out the molded product to the process of raising the elevating part 44 is performed on the mold 13a side. Then, the slide table 12 is operated by the operation of the table driving hydraulic cylinder 20.
Is moved to the left in FIG. 5, so the mold 13b has completed cooling.
Is located directly below the injection unit 16. In this state, the elevating part 44 is lowered while the die clamps 41a and 41b are retracted. At this time, the pair of opposing clamp claws 43 pass downward through the opposing notches 45 of the mold clamping plate 35b, and then the die clamps 41a, 4a, 4b.
By the operation of 1b, they approach each other and come into contact with the lower part of the moving mold 36.

At this point, the clamp hydraulic cylinder 31
Outputs a signal for extending operation of ~ 34. Then, the working oil is supplied to the going ports P ₁ and P ₃ of the clamping hydraulic cylinders 31 to 34 through the port 90, and the working oil in the pressure chambers 56b and 57b is drained from the returning port P ₂ respectively. Then, the clamping hydraulic cylinders 31 to 34 are extended and the mold clamping force is released. Also in this case, the clamping hydraulic cylinders 27 to 30
Clamping hydraulic cylinders 31-34
When the hydraulic oil goes into the ports P ₁ and P ₃ respectively, the piston rods PR ₁ and PR ₂ are extended by the same amount at the same timing. At the same time as this, the elevating part 44 is raised, the moving mold 36 of the mold 13b is lifted together with the mold clamping plate 35b and separated from the fixed mold 37, the mold 13b is opened, and molding is performed from this mold 13b. Take out the item.

Thereafter, the elevating part 44 is lowered, and at the same time,
The hydraulic cylinders 31 to 34 for clamping are contracted and operated.
To output the signal. Then, the hydraulic cylinder for each clamp
Return port P of Da 31-34₂ Via port 91
Hydraulic oil is supplied, going port P₁ And P_Three To pressure chamber 5
The hydraulic oils in 6a and 57a are drained,
The hydraulic cylinders 31 to 34 for ramps are compressed at high pressure.
Also in this case, the clamp hydraulic cylinders 27 to 30
The hydraulic cylinders 31-34 for clamping are
In each case, hydraulic oil is returned to port P₂ When pressed into
Ton rod PR ₁ , PR₂ Same amount at the same timing
Activate the contraction. As a result, the mold clamping plate 35b is strong.
And the moving die 36 of the die 13b is moved down to the fixed die 3
7 is strongly pressed and the mold is clamped.

Further, the nozzle shutter 8 is opened, the injection nozzle 26 is connected to the nozzle opening 39a of the mold clamping plate 35b, and the molten molding resin material is filled in the mold 13b. When the filling is completed, the injection nozzle 26 is raised with respect to the elevating part 44 to separate from the mold 13b, and the nozzle shutter 8
Close. And after this, the hydraulic cylinder for clamping 3
The pressure of 1 to 34 is maintained to maintain the mold clamping force.

With the injection nozzle 26 positioned above the mold 13b, the molding conditions on the computer are changed for the next mold 13a. The resin amount according to this molding condition is measured and stored in the injection unit 16. Then, the die clamps 21a and 21b are retracted to move the lower step portion 22 of the die 13b.
Lifting and lowering part 44 releasing the injection nozzle 26 and retracting the injection nozzle 26.
To raise (back). Further, the table driving hydraulic cylinder 20 is contracted to move the slide table 12 straight to the right in FIG. 5, and this time the mold 13a is positioned directly below the injection unit 16, and the lower step 2 of the mold 13a is moved.
2 is pressed and fixed by the clamp claws 23 of the die clamps 21a and 21b. The mold 13b, which is located below the injection unit 16, maintains a predetermined mold clamping force by the holding pressure by the hydraulic cylinders 31 to 34 for clamping, and is cooled for a predetermined time. Processes such as injection are performed on the mold 13a.

As described above, according to the clamping hydraulic cylinders 27 to 30, 31 to 34 of the present invention, the mold 13 is
It is possible to apply a uniform force to a and 13b through the mold clamping plates 35a and 35b to provide a stable mold clamping force, and also to have two piston rods P included in each.
R ₁ and PR ₂ can be operated in the same amount at the same timing without using a complicated hydraulic circuit. Therefore, as compared with the case where a large number of hydraulic cylinders each having only one piston rod are used, it is possible to suppress an increase in the accommodation space of the hydraulic cylinders.

[0045]

As described above, according to the present invention, it is possible to provide a dual rod hydraulic cylinder device that can apply a stable mold clamping force to a mold and can suppress an increase in the accommodation space of the hydraulic cylinder as much as possible. can do.

[Brief description of drawings]

FIG. 1 shows a main part of an embodiment of a slide molding apparatus using a dual rod hydraulic cylinder device according to the present invention.
2 is a view seen in the direction of arrow II in FIG.

FIG. 2 is an arrow in FIG. 5, showing a main part of the slide molding apparatus.
It is a view seen from the direction II-II.

FIG. 3 is an arrow in FIG. 5, showing a main part of the slide molding apparatus.
It is the figure which looked at III-III direction.

FIG. 4 is a side view showing a main part of the slide molding apparatus.

FIG. 5 is a side view showing a main part of the slide molding apparatus.

FIG. 6 is a front sectional view showing a structure of a hydraulic cylinder for clamping according to the present invention.

FIG. 7 is a front cross-sectional view showing a state of the clamping hydraulic cylinder during an extension operation.

FIG. 8 is a front view showing the clamp hydraulic cylinder.

FIG. 9 is a side view showing the clamp hydraulic cylinder.

FIG. 10 is a side view showing a state of a flow path of the clamp hydraulic cylinder.

FIG. 11 is a plan view showing the clamp hydraulic cylinder.

FIG. 12 is a schematic view showing an example of a forming die provided on a fixed die and a moving die.

FIG. 13 is a schematic cross-sectional view of an injection nozzle portion of an injection unit.

FIG. 14 is a diagram showing an operation example of the embodiment of the slide molding apparatus.

[Explanation of symbols]

27 28 Clamp hydraulic cylinder (dual rod hydraulic cylinder device) 29 30 Clamp hydraulic cylinder (dual rod hydraulic cylinder device) 31 32 Clamp hydraulic cylinder (dual rod hydraulic cylinder device) 33 34 Clamp hydraulic cylinder (dual rod hydraulic cylinder device) Device) 57 57 Piston cylinder chamber 56a 57a Pressure chamber (front pressure chamber) 56b 57b Pressure chamber (rear pressure chamber) 59 60 Piston body 62a 62b 61 76 81 Flow path (cylinder body internal passage) 63 Cylinder fixing member 80a 80b Flow Road CB Cylinder body P ₁ P ₃ Go port P ₂ Return port PR ₁ PR ₂ Piston rod

Claims (2)

[Claims] 1. A pair of piston cylinder chambers formed in parallel with each other in a single cylinder body; a pair of piston bodies slidably fitted in the piston cylinder chambers and forming pressure chambers in the front and rear thereof, respectively. A pair of piston rods that are respectively fixed to the pair of piston bodies and are not coupled to each other; go ports that are opened in the cylinder body and that communicate with one and the other of the pressure chambers in front of and behind the pair of piston bodies, respectively. Return port; The flow path distance from the going port to the front pressure chambers of the pair of piston bodies is set to be equal; and the flow path from the return port to the rear pressure chambers of the pair of piston bodies. The distances are set equal;
A dual rod hydraulic cylinder device. 2. The cylinder according to claim 1, wherein a pair of outgoing ports are formed directly in the cylinder body so as to correspond to the pair of piston bodies, and one return port is opened in the cylinder body,
A dual rod hydraulic cylinder device communicating with a pair of pressure chambers via a passage in the cylinder body.