JPH07108542B2 - Injection machine injection machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection device of an injection molding machine equipped with an injection cylinder incorporating an injection piston having a screw at its tip.

[0002]

2. Description of the Related Art Generally, an injection molding machine comprises a mold device and an injection device. FIG. 4 shows a conventional injection device, in particular, an injection cylinder 51 having a double rod type injection piston 52 built therein and a front oil chamber 5 in front of the piston body 52m.
3f shows the injection device 50 in which the pressure receiving areas of the rear oil chamber 53r are the same. In this type of injection device 50, if the hydraulic pump 56 and the oil tank 57 are connected to the front oil chamber 53f and the rear oil chamber 53r of the injection cylinder 51 via the four-port servo valve 55, meter-in control and meter-out control are performed. Can be simultaneously performed, high responsiveness and stability can be ensured during speed control of the screw 58 coupled to the front end of the injection piston 52, and highly accurate control can be realized. Incidentally, 59 is a central processing unit,
The speed (speed detection value) is calculated from the position detection value obtained from the position sensor 60 that detects the position of the screw 58, and control information is generated based on this speed detection value and the speed setting value set by the setting unit 61. , And to the control input section of the servo valve 55 via the amplifier 62. Thereby, speed feedback control is performed so that the speed of the screw 58 becomes the speed set value.

[0003]

However, the above-mentioned conventional injection device 50 has a double rod type injection piston 52,
That is, since the piston body portions 52m are provided with the piston rod portions 52f and 52r having the same diameter at both ends, the entire length of the injection cylinder 51 including the piston rod portions 52f and 52r in the front-rear direction is significantly increased, and the entire injection molding machine is large. There was a problem that caused the change. Also, normally, this type of injection cylinder 51
An oil motor for rotating the injection piston 52 is attached to the rear end, but the rear piston rod portion 52r projects rearward from the rear end of the injection cylinder 51, which complicates the mounting structure of the oil motor. was there.

The present invention solves the problems existing in the prior art as described above. The length of the injection molding machine is shortened by shortening the length in the front-rear direction, and the assembling property is improved by simplifying the structure. Another object of the present invention is to provide an injection device of an injection molding machine that can reduce the cost.

[0005]

The present invention is directed to an injection piston 3
In constructing the injection device 1 of the injection molding machine including the injection cylinder 2 having a built-in cylinder, in particular, the inner cylinder portion 5 having the rear end opened is formed inside the single rod type injection piston 3, and the injection cylinder 2 The fixed piston portion 6 that is inserted into the inner cylinder portion 5 is provided at the inner rear end, and the pressure receiving area Sf of the front oil chamber 2f and the inner cylinder portion of the injection cylinder 2 located in front of the piston body portion 3m of the injection piston 3 are 5, the pressure receiving area Si of the inner oil chamber 5i is the same.

In this case, the injection device 1 is provided with a rotary drive portion 7 at the outer rear end of the injection cylinder 2, and the rotary shaft portion 7s of the rotary drive portion 7 is rotatably penetrated into the fixed piston portion 6. The tip end side of the rotary shaft portion 7s can be spline-coupled to the injection piston 3. Further, the fixed piston portion 6 may be provided with an oil passage 8 for supplying or discharging oil to / from the inner oil chamber 5i. Furthermore, the injection piston 3 has a tubular body portion 9 and a shaft body portion 10 rotatably supported inside the tubular body portion 9, and the tip end side of the rotary shaft portion 7s is splined to the shaft body portion 10. It can also be configured.

[0007]

According to the injection device 1 of the injection molding machine of the present invention, the inner cylinder portion 5 having the rear end opened is formed inside the injection piston 3, and the inner cylinder portion is formed at the inner rear end of the injection cylinder 2. The injection piston 3 can be configured as a single rod type because the fixed piston portion 6 that is inserted into the piston 5 is provided. Therefore, the piston rod portion on the rear side is unnecessary, and the entire length of the injection cylinder 2 including the injection piston 3 can be shortened accordingly. Further, since the piston rod portion of the injection piston 3 does not project from the rear end of the injection cylinder 2, the rotary drive unit 7 such as an oil motor can be directly attached to the outer rear end surface of the injection cylinder 2, and no special attachment structure is required. Becomes

On the other hand, since the pressure receiving area Sf of the front oil chamber 2f in the injection cylinder 2 located in front of the injection piston 3 and the pressure receiving area Si of the inner oil chamber 5i in the inner cylinder portion 5 are the same, for example, the front oil chamber If a hydraulic pump and an oil tank are connected to 2f and the inner oil chamber 5i via a servo valve, meter-in control and meter-out control can be performed at the same time.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, the principle configuration and operation including the control system of the injection apparatus 1 according to the present invention will be described with reference to FIG.

Reference numeral 2 is an injection cylinder, which contains a single rod type injection piston 3. The injection piston 3 has a piston rod portion 3s and a piston body portion 3m. The piston rod portion 3s projects forward from the front end of the injection cylinder 2 and the screw 4 is coupled to the front end of the piston rod portion 3s.

Further, an inner cylinder portion 5 having a rear end opened is formed inside the injection piston 3, and a fixed piston portion 6 which is inserted into the inner cylinder portion 5 is provided at the inner rear end of the injection cylinder 2. As a result, the front oil chamber 2 is provided inside the injection cylinder 2 located in front of the piston body 3m.
f is provided, and an inner oil chamber 5i is provided inside the inner cylinder portion 5. Further, the pressure receiving area Sf of the front oil chamber 2f and the pressure receiving area Si of the inner oil chamber 5i are selected to be the same according to the present invention.

On the other hand, 21 is a four-port servo valve, and the front oil chamber 2f and the inner oil chamber 5i are connected to the hydraulic pump 22 and the oil tank 23 via the servo valve 21. Also,
Reference numeral 24 denotes a central processing unit. The central processing unit 24 has, as input information, a pressure detection value from a pressure sensor 25 attached to the front oil chamber 2f, a pressure detection value from a pressure sensor 26 attached to the inner oil chamber 5i, and Position sensor 2 attached to the screw 4 side
The position detection value from 7 is added and the setting unit 28
Various setting values such as a pressure setting value, a position setting value, and a speed setting value are given from. On the other hand, the central processing unit 24 gives control information for performing feedback control to the control input unit of the servo valve 21 via the amplifier 29.

Therefore, if the servo valve 21 is switched to the symbol on the left side or the right side, the pressure oil of the hydraulic pump 22 is changed to the front oil chamber 2.
f or the internal oil chamber 5i is selectively supplied, and the injection piston 3, that is, the screw 4 moves backward or forward. At this time, the central processing unit 24 obtains the speed (speed detection value) of the screw 4 by differentiating the position detection value from the position sensor 27,
The control information based on the deviation from the speed setting value is generated and given to the control input section of the servo valve 21. As a result, the sprue built in the servo valve 21 is displaced by the stroke amount corresponding to the size of the control information, and the speed feedback control is performed. In this case, flow rate control, that is, meter-in control and meter-out control is performed for both supply and discharge of pressure oil to the injection cylinder 2, and, for example, high responsiveness and stability during speed control of the injection process. Can be secured, and high-accuracy control (positioning accuracy, etc.) can be realized.

Next, the main body structure which constitutes the main part of the injection device 1 according to the present invention will be described more specifically with reference to FIG.

Reference numeral 31 is an injection cylinder block having a rear end opening which constitutes the injection cylinder 2, and the rear end opening is closed by a cylinder cover 32. The injection cylinder 2 has a built-in injection piston 3, and the injection piston 3 penetrates the front end portion 2a of the injection cylinder 2 and projects forward.
s and a piston body 3m integrally formed at the rear of the piston rod 3s. As a result, the front oil chamber 2f is provided inside the injection cylinder 2 located in front of the piston body 3m. Also, the piston rod part 3s
The rear end of the screw 4 is attached to the front end of the screw holding ring 33.
And using the screw split ring 34. In addition,
Reference numeral 35 is a heating cylinder through which the screw 4 is inserted, and is supported by the front part of the injection cylinder block 31.

On the other hand, an inner cylinder portion 5 is formed inside the injection piston 3 and is closed by a piston cover 36.
Further, the fixed piston portion 6 is provided on the inner surface of the cylinder cover 32.
Is integrally formed, and the fixed piston portion 6 is formed by the inner cylinder portion 5
To insert. As a result, the inner oil chamber 5i is provided inside the inner cylinder portion 5. Furthermore, the cylinder cover 3
An oil passage 8 extending from the outer side surface to the tip end surface of the fixed piston portion 6 is provided inside 2, and a bearing hole 32h through which a rotary shaft portion 7s described later is inserted is provided at the center.

On the other hand, on the rear end surface of the cylinder cover 32 which is the outer rear end of the injection cylinder 2, an oil motor 7m constituting the rotary drive unit 7 is mounted. The oil motor 7m has a rotating shaft portion 7s. The rotating shaft portion 7s rotatably penetrates the bearing hole 32h of the cylinder cover 32, and the spline shaft portion 37 formed on the tip side thereof is attached to the injection piston 3. The spline ring 38 is spline-coupled. In addition, 39 is a manifold for connecting the oil passage 8 (inner oil chamber 5i) and the front oil chamber 2f to the servo valve 21, and 40 is an air breather.

According to the present invention, the pressure receiving area Sf of the front oil chamber 2f and the pressure receiving area Si of the inner oil chamber 5i are selected to be the same. Therefore, if the pressure oil is selectively supplied to the front oil chamber 2f or the inner oil chamber 5i, the screw 4 moves backward or forward, and if the oil motor 7m is operated, the rotating shaft portion 7s rotates, Further, the screw 4 rotates via the injection piston 3.

Since the injection device 1 is constructed in this way,
The rear piston rod portion of the injection piston 3 is practically unnecessary and does not project from the rear end of the injection cylinder 2. Therefore, the entire length of the injection cylinder 2 including the injection piston 3 in the front-rear direction can be shortened by that amount, and the overall size of the injection molding machine can be reduced. Further, since the oil motor 7m can be directly attached to the outer rear end surface of the injection cylinder 2, no special attachment structure is required.
Therefore, the assembling property can be improved and the cost can be reduced by simplifying the structure.

On the other hand, FIG. 3 shows a modified embodiment according to the present invention. In FIG. 3, the same parts as those in FIG. 2 are designated by the same reference numerals to clarify the configuration thereof, and detailed description thereof will be omitted.

The modified embodiment relates to a structural modification of the injection piston 3. That is, in the embodiment shown in FIG. 2, the injection piston 3 rotates together with the rotation of the rotary shaft portion 7s in the oil motor 7m, but in the modified embodiment, the injection piston 3 is connected to the tubular portion 9 and the tubular portion 9. The shaft body 10 is rotatably supported inside, and the shaft body 10
In addition, the tip side of the rotating shaft portion 7s is spline-coupled. Therefore, in the case of the modified embodiment, only the shaft body portion 10 rotates due to the rotation of the rotary shaft portion 7s, and the piston body portion 3
The cylindrical portion 9 having m has the advantage that it does not rotate. The screw 4 is coupled to the shaft portion 10. 41 and 4 in FIG.
Reference numerals 2 and 43 are bearings, and 44 is a bearing pressing block.

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment,
The detailed configuration, shape, and the like can be arbitrarily changed without departing from the scope of the present invention.

[0024]

As described above, in the injection apparatus of the injection molding machine according to the present invention, the inner cylinder portion having the rear end opened is formed inside the single rod type injection piston, and the inner rear end of the injection cylinder is Since the fixed piston portion that is inserted into the inner cylinder portion is provided, and the pressure receiving area of the front oil chamber and the pressure receiving area of the inner oil chamber in the inner cylinder portion of the injection cylinder located in front of the piston body portion of the injection piston are made the same. It has the following remarkable effects.

Since the rear piston rod portion of the injection piston is virtually unnecessary, the entire length of the injection cylinder including the injection piston in the front-rear direction can be shortened accordingly.
It is possible to reduce the size of the entire injection molding machine.

Since a rotation drive unit such as an oil motor can be directly attached to the outer rear end surface of the injection cylinder,
No special mounting structure is required, and the assembling property can be improved and the cost can be reduced by simplifying the structure.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram including a control system of an injection device according to the present invention,

FIG. 2 is a vertical sectional side view of a main body structure of the injection device,

FIG. 3 is a vertical sectional side view of a main body structure according to a modified embodiment of the injection device,

FIG. 4 is a principle configuration diagram including a control system of an injection device according to a conventional technique,

[Explanation of symbols]

 1 Injection Device 2 Injection Cylinder 2f Front Oil Chamber 3 Injection Piston 3m Piston Body 4 Screw 5 Inner Cylinder 5i Inner Oil Chamber 6 Fixed Piston 7 Rotation Drive 7s Rotation Shaft 8 Oil Passage 9 Tubular Body 10 Shaft Body

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hiroo Okubo Hiroo Okubo 2110 Nanjo, Osaka Castle, Hanashina-gun, Nagano Prefecture Nissei Jushi Kogyo Co., Ltd. (56) Bibliography Sho 62-199511

Claims (4)

[Claims] 1. An injection device of an injection molding machine comprising an injection cylinder having a built-in injection piston, wherein an inner cylinder portion having a rear end opening is formed inside a single rod type injection piston, and an inner rear end of the injection cylinder. In addition, the fixed piston part that is inserted into the inner cylinder part is provided, and the pressure receiving area of the front oil chamber in the injection cylinder located in front of the piston body of the injection piston is made equal to the pressure receiving area of the inner oil chamber in the inner cylinder part. An injection device of an injection molding machine, which is characterized in that 2. A rotation drive section is provided at an outer rear end of the injection cylinder, the rotation shaft section of the rotation drive section is rotatably penetrated into the fixed piston section, and the tip end side of the rotation shaft section is injected into the injection piston. The injection device of the injection molding machine according to claim 1, wherein the injection device is a spline connection. 3. The injection piston has a tubular body and a shaft body which is rotatably supported inside the tubular body, and the tip end side of the rotary shaft is splined to the shaft body. The injection device of the injection molding machine according to claim 1. 4. The injection device of an injection molding machine according to claim 1, wherein the fixed piston portion is provided with an oil passage for supplying or discharging oil to / from the inner oil chamber.