JPH0581430B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flexible resin mandrel used for manufacturing hoses, and particularly to an apparatus for manufacturing a resin mandrel having a highly accurate outer diameter.

[Conventional technology]

Conventionally, a device as shown in Fig. 2 has been used to manufacture resin mandrels. Raw resin pellets are fed into a hopper dryer 2 of an extruder 1, and while being heated and melted by the extruder 1, the molten resin is produced by rotating a screw. 4 is continuously extruded from an extrusion head 3, passed through a sizing die 5 of a predetermined inner diameter, and formed into a circular cross-section, and then cooled in a cooling water tank 6. The method used is to pick it up. The resin mandrel 8 that has come out of the take-up machine 7 is wound onto a winding plate or the like by a wind-up machine 9.

The outer diameter φ of the resin mandrel 8 manufactured in this manner is primarily determined by the relationship between the inner diameter of the sizing die 5 and the drawing speed of the resin mandrel 8 by the drawing machine 7. Therefore, in the past, the resin mandrel 8 was wound while being taken off at a taking-off speed determined empirically according to the inner diameter of the sizing die 5.
The outer diameter dimension was controlled by actually measuring the outer diameter φ with a caliper or the like, and finely adjusting the take-up speed sequentially according to the obtained outer diameter measurement value.

The outer diameter φ of the resin mandrel actually obtained by such conventional outer diameter size control cannot be strictly constant; for example, when the standard value of the outer diameter φ is 7.1 mm, there is a large variation of about ±0.10 mm. Ta.

However, as the performance of automobiles has improved recently, there has been a tendency to place more emphasis on the inner diameter of hoses used in high-pressure fuel injection hoses, etc., and for this reason, there is a need to improve the accuracy of the outer diameter dimensions of resin mandrels used for manufacturing hoses. It became like that.

In order to manufacture hoses with the desired high-precision inner diameter, resin mandrels manufactured using conventional methods cannot be used in areas where the outer diameter exceeds a specified tolerance, resulting in an extremely low mandrel manufacturing yield. It was hot.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION In view of the conventional circumstances, it is an object of the present invention to provide an apparatus that can easily manufacture a resin mandrel having a highly accurate outer diameter.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a resin mandrel manufacturing apparatus in which a molten resin continuously extruded from an extruder is molded into a circular cross section through a sizing die, and the resin mandrel obtained by cooling is continuously taken off by a take-off machine. A first outer diameter measuring device that measures the outer diameter of the resin mandrel after cooling is used, and the measured outer diameter of the resin mandrel is compared with a predetermined reference value,
a first controller that increases or decreases the take-up speed in accordance with an increase or decrease from a reference value; a second outer diameter measuring device that measures the outer diameter of the molten resin between the extrusion head and the sizing die of the extruder; , a second control device that compares the measured outer diameter of the molten resin with a predetermined reference value and reduces or increases the amount of molten resin discharged from the extruder in accordance with the increase or decrease from the reference value. Features.

[Effect]

As mentioned above, the outer diameter φ of the resin mandrel is primarily determined by the relationship between the inner diameter of the sizing die and the take-up speed of the resin mandrel, but since the molten resin to be extruded is flexible, the The molten resin is drawn into the sizing die while its outer diameter gradually decreases, and the outer diameter D at a predetermined position between the two also fluctuates due to subtle changes in the discharge rate of the extruder. It was found that the outer diameter φ of the resin mandrel was influenced by

Therefore, in the present invention, in addition to the usual control of the take-up speed of the resin mandrel, the outer diameter D of the molten resin between the extrusion head and the sizing die is measured, and this value is always kept at a constant reference value. By controlling the amount of molten resin discharged so that This allows quick control and management, and as a result, it has become possible to easily manufacture resin mandrels with extremely high outside diameter accuracy, without requiring human labor, compared to conventional methods.

As the outer diameter measuring device, an optical scanning dimension measuring device or the like can be used, which uses a light receiving section to detect the shadow of a parallel-scanned light beam of a semiconductor laser or the like hitting the resin mandrel or molten resin. Further, as the control device, a commercially available computer control device can be used, but a control device that performs a PI or PID control operation is particularly preferred.

〔Example〕

A specific example of the present invention will be explained with reference to FIG.

The main body of this resin mandrel manufacturing apparatus is the same as the conventional one, and is a resin extruder equipped with a hopper dryer 2 into which raw resin pellets are input, and an extrusion head 3 which continuously extrudes molten resin 4 by rotating a screw. 1. A sizing die 5 with a predetermined inner diameter that molds the molten resin 4 extruded from the extruder 1 into a circular cross section, a cooling water tank 6 provided continuously to the sizing die 5, and a resin mandrel 8 obtained by cooling the resin mandrel 8 continuously. It consists of a take-up machine 7 for take-up, and a winder 9 for a resin mandrel 8 installed behind the take-off machine 7.

Furthermore, in this device, a cooling water tank 6 and a take-up machine 7 are provided.
During the first step, the outer diameter φ of the resin mandrel 8 is measured.
A first controller 11 comprising an outer diameter measuring device 10 compares the obtained outer diameter measurement value with a predetermined reference value in a first control device 11 consisting of a commercially available PID control device, and generates a control signal according to an increase or decrease from the reference value. By changing the rotation speed of the motor of the take-up machine 7, the take-up speed is increased or decreased. The withdrawal speed may be controlled sequentially, but in this device, if the withdrawal speed is set to an appropriate value first, it can be kept constant from then on, and the outer diameter accuracy can be maintained by controlling the outer diameter of the molten resin 4 as described below. A resin mandrel 8 having a sufficiently high value can be obtained.

Further, a second outer diameter measuring device 12 is provided at a predetermined position between the extrusion head 3 and the sizing die 5 of the extruder 1, and measures the outer diameter D of the molten resin 4. Second
The outer diameter measurement value of the molten resin 4 measured by the outer diameter measuring device 12 is transferred to the second control device 1 which is a commercially available PID control device.
3, the screw rotation speed of the extruder 1 is changed by a control signal according to the increase or decrease from the reference value, and the amount of molten resin discharged from the extruder 1 is decreased or increased. It's becoming like that.

According to the apparatus of the present invention, the outer diameter D of the molten resin 4 can be controlled with an accuracy of about ±0.2 mm with respect to the reference value, and therefore the outer diameter φ of the resin mandrel can be controlled with an accuracy of about ±0.035 mm with respect to the reference value. It can be managed with much higher precision than before! Moreover, by setting the distance between the extrusion head 3 of the extruder 1 and the sizing die 5 to 30 to 90 mm, minute changes in the amount of molten resin discharged can be absorbed during this time, eliminating deviations in control timing. The outer diameter D of the molten resin 4 and, in turn, the outer diameter φ of the resin mandrel can be controlled with even higher precision.

Using the above device, measure the distance between the extrusion head 3 with an extrusion diameter of approximately 14 mm and the sizing die 5 with an inner diameter of 7.5 mm.
45 mm, and a polyester resin mandrel with an outer diameter standard value of 7.1 mm was manufactured. First, while measuring the outer diameter φ of the resin mandrel 8 with the first outer diameter measuring device 10, the first controller 11 automatically increases or decreases the take-up speed, and when the resin mandrel 8 with an outer diameter of 7.1 mm is obtained. The withdrawal speed was fixed. The outer diameter dimensional accuracy of the resin mandrel 8 obtained at this stage is approximately 7.1±
It was 0.10mm. Next, the outer diameter D of the molten resin 4 is measured by the second outer diameter measuring device 12 installed at a position 20 mm from the extrusion head 3 while keeping the take-up speed fixed, and the screw rotation of the extruder 1 is controlled by the second controller 13. The amount of molten resin discharged was controlled by automatically changing the number. The outer diameter D of the molten resin 4 is 12 to 14 mm before starting control.
Although there was some variation within the range of
The outside diameter of the resin mandrel 8 obtained was 7.1 mm ^+0.04 _-0.03 mm, which was extremely high precision.

〔Effect of the invention〕

According to the apparatus of the present invention, it is possible to automatically manage the outside diameter of the molten resin from the extruder as well as the take-up speed of the resin mandrel, and easily manufacture a resin mandrel having an extremely highly accurate outside diameter. .

Moreover, even when changing the outer diameter depending on the type of resin mandrel being manufactured, the setting of the take-up speed, the discharge amount of molten resin, and the management of the outer diameter can be done automatically.
Since the process is carried out quickly and accurately, it is possible to easily switch to manufacturing other types of resin mandrels with high outer diameter accuracy in a short time.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a high-precision resin mandrel manufacturing apparatus according to a specific example of the present invention, and FIG.
The figure is a schematic diagram of a conventional resin mandrel manufacturing apparatus. 1...Extruder, 2...Hopper dryer, 3
... Extrusion head, 4 ... Molten resin, 5 ... Sizing die, 6 ... Cooling water tank, 7 ... Taking machine, 8 ...
... Resin mandrel, 9 ... Winding machine, 10 ... 1st
Outer diameter measuring device, 11...first control device, 12...second outer diameter measuring device, 13...second control device.

Claims (1)

[Scope of Claims] 1. In a resin mandrel manufacturing apparatus in which a molten resin continuously extruded from an extruder is molded into a circular cross-section through a sizing die, and the resin mandrel obtained by cooling is continuously taken up by a take-up machine, a first outer diameter measuring device for measuring the outer diameter of the resin mandrel;
A first control device that compares the measured outer diameter of the resin mandrel with a predetermined reference value and increases or decreases the take-up speed according to the increase or decrease from the reference value, and an extrusion head and a sizing die of the extruder. A second outer diameter measuring device is used to measure the outer diameter of the molten resin, and the outer diameter measurement value of the molten resin is compared with a predetermined reference value, and the molten resin of the extruder is adjusted depending on the increase or decrease from the reference value. 1. A high-precision resin mandrel manufacturing apparatus, comprising: a second control device that reduces or increases the discharge amount. 2. Claim 1, characterized in that the distance between the extrusion head of the extruder and the sizing die is 30 to 90 mm.
The described high-precision resin mandrel manufacturing equipment.