JP2006001768A - Glass forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass forming apparatus capable of performing precise glass forming by accurately controlling pressing force by a mold. <P>SOLUTION: In the glass forming apparatus, a load detector 8d is attached between a fixed shaft 2a and an upper mold 4 and disposed in a forming chamber 17. Thereby the load detector 8d is not influenced by pressure reduction in the forming chamber 17. Between the load detector 8d and the upper mold 4, a cooling member 31 is disposed, and further, the forming chamber 17 is partitioned into a part surrounded by transparent quartz tubes 16 and housing the upper mold 4 and a lower mold 11, and a part surrounded by a cooling chamber 52 and housing the load detector 8d, by the cooling member 31, a flange 32 and a separating plate 54, thus suppressing the temperature rise of the load detector 8d. Also cooling piping 34 and gas piping 41 are bent in their mid-stream in a loop-like form so as not to influence the load measurement by the load detector 8d. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a glass molding apparatus, and more particularly to a glass molding apparatus suitable for manufacturing a glass molded product that requires high shape accuracy such as a precision glass lens.

  FIG. 4 shows an example of a conventional glass forming apparatus.

  The fixed shaft 2 is fixed to the upper part of the apparatus frame 1 and extends downward. An upper mold 4 (fixed mold) is attached to the lower end of the fixed shaft 2 via a ceramic heat insulating cylinder 3. A screw jack 8 and a servo motor 8a serving as a driving source for the screw jack 8 are accommodated in the lower portion of the apparatus frame 1. The moving shaft 9 is connected to the screw jack 8 via a load detector 8b at the lower end thereof, and extends upward so as to face the fixed shaft 2. A lower die 11 (moving type) is attached to the upper end of the moving shaft 9 via a ceramic heat insulating cylinder 10.

  The upper die 4 and the lower die 11 are metal die plates 5 and 12, cores 6 and 13 made of ceramics or superalloy, and the cores 6 and 13 are fixed to the die plates 5 and 12 and part of the die. It is comprised from the fixed die 7 and the moving die | dye 14 which comprise.

  An upper plate 15 that is moved up and down by a driving device (not shown) is slidably attached to the fixed shaft 2 while maintaining an airtight state. A transparent quartz tube 16 surrounding the periphery of the upper mold 4 and the lower mold 11 is attached to the upper plate 15 to form a molding chamber 17. Further, an outer cylinder 18 surrounding the transparent quartz tube 16 is attached to the upper plate 15, and a lamp unit 19 is provided along the inner wall of the outer cylinder 18.

  The lamp unit 19 ejects cooling air toward the outer peripheral surface of the infrared lamp 20, a reflection mirror 21 disposed behind the infrared lamp 20, a water cooling pipe 22 for cooling the reflection mirror 21, and the transparent quartz tube 16. Air cooling means (not shown).

Inside the fixed shaft 2 and the moving shaft 9, gas supply paths 23 and 24 for filling the inside of the molding chamber 17 with an inert gas such as N ₂ gas or cooling the upper mold 4 and the lower mold 11 are provided. Is provided. The upper plate 15 is also provided with a gas supply path 25, and an inert gas is supplied into the molding chamber 17. The inert gas supplied to the molding chamber 17 is discharged from an exhaust port 26 formed in the intermediate plate 1 a that forms the lower portion of the molding chamber 17.

  When forming using this glass forming apparatus, the temperature of the lower mold 11 (not shown but the same applies to the upper mold 4) is detected by the thermocouple 27, and the output of the lamp unit 19 is output by the control apparatus 28. The upper die 4 and the lower die 11 and the glass material 30 are heated by controlling the speed, torque and rotation amount of the servo motor 8a by the control device 28 in association with the detected temperature, so that the moving shaft 9 is previously set. Move according to the set program.

  At this time, the control of the pressing force between the upper die 4 and the lower die 11 is such that the load transmitted from the screw jack 8 to the moving shaft 9 is detected by the load detector 8b, and the load becomes a predetermined value. I was doing it.

However, in such a glass forming apparatus, since the load detector 8b is attached to the lower end portion of the moving shaft 9 and is located outside the forming chamber 17, there are the following problems with respect to detection accuracy of the pressing force. It was. That is, when the pressure in the molding chamber 17 is reduced during molding, the moving shaft 9 is pulled upward to affect the measurement value by the load detector 8b, and thereby the measurement value by the load detector 8b, the upper mold 4 and the lower mold. An error occurs between the pressing forces applied during the period 11, and as a result, the pressing force cannot be accurately controlled.
JP-A-8-208243

  The present invention was made to solve the problems in the conventional glass forming apparatus as described above, and the object of the present invention is to increase the measurement accuracy of the pressing force applied between the molds, thereby An object of the present invention is to provide a glass forming apparatus capable of performing more precise glass forming.

The glass forming apparatus of the present invention is
A molding chamber;
A stationary mold and a movable mold arranged to face each other in the molding chamber;
A fixed shaft that supports the fixed mold from the back side;
A moving shaft that supports the movable mold from the back side;
A drive device for moving the moving axis with respect to the fixed mold by speed, load or position control according to a preset program;
A heating device for heating the stationary mold, the movable mold and the glass material put between them;
Gas supply means for supplying an inert gas into the molding chamber;
An evacuation device for depressurizing the molding chamber;
A load detector for detecting a pressing force acting between the fixed mold and the movable mold;
In a glass forming apparatus comprising:
The load detector is inserted either between the fixed shaft and the fixed mold or between the movable shaft and the movable mold, and is arranged in the molding chamber.

  According to the glass molding apparatus of the present invention, since the load detector is arranged in the molding chamber, pressure fluctuations in the molding chamber do not affect the output of the load detector, and the upper and lower molds are not affected. The measurement accuracy of the pressing force can be increased.

  Preferably, a cooling member is inserted between the fixed type or the movable type and the load detector, and a path through which the cooling water circulates is formed inside the cooling member. By comprising in this way, the inflow of the heat | fever from the said fixed type | mold or a moving type | mold to the said load detector can be suppressed.

  Preferably, a cooling water pipe is connected between the fixed shaft or the moving shaft and the cooling member, and the cooling water is passed from the cooling water flow path provided in the fixed shaft or the moving shaft through the cooling water pipe. And introduced into the cooling member. In that case, it is preferable to form a loop in the middle of the cooling water pipe, thereby generating a large reaction force in the cooling water pipe due to a variation in the distance between the fixed shaft or moving shaft and the cooling member. So that it can be absorbed without letting go.

  Preferably, cooling water stabilization means for suppressing fluctuations in the supply pressure and flow rate of the cooling water is further provided.

  Preferably, a flange is inserted between the fixed mold or the movable mold and the cooling member, a path through which an inert gas flows is provided inside the flange, and the inert gas is introduced into the fixed shaft or the movable shaft. A gas pipe for introducing into the inside of the flange is provided from the provided gas flow path. In that case, the gas is so introduced that the inert gas is introduced into the molding chamber via the gas flow path provided in the fixed shaft or the moving shaft, the gas pipe, and the path inside the flange. A supply means is comprised.

  Even in this case, it is preferable that the middle of the gas pipe is formed in a loop shape, thereby generating a large reaction force in the gas pipe due to a variation in the distance between the fixed shaft or the moving shaft and the cooling member. So that it can be absorbed without letting go.

  Preferably, there is further provided a pressure flow control valve for increasing the supply pressure and flow rate of the inert gas supplied into the cooling member by gradient control for gradually increasing the supply pressure and flow rate. Preferably, the molding chamber is divided into a first part that accommodates the fixed mold and the movable mold and a second part that accommodates the load detector, and the heating device is limited to the first part. Deploy. By comprising in this way, the inflow of the heat | fever to the said load detector can further be suppressed.

  More preferably, the molding chamber is configured so that the wall surface can be cooled in the second portion.

  Preferably, the first part and the second part of the molding chamber are configured to be supplied with an inert gas separately.

  According to the present invention, as described above, the load detector is attached to either the fixed shaft and the fixed mold or between the movable shaft and the movable mold and is disposed in the molding chamber. Is not affected by the reduced pressure in the molding chamber. For this reason, it becomes possible to measure the pressing force of the mold more accurately and to control it more accurately, and to perform precise glass molding such as a minute glass lens.

  Next, the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an example of a glass forming apparatus according to the present invention. In the figure, 2a is a fixed shaft, 9 is a moving shaft, 4 is an upper die (fixed die), 11 is a lower die (moving die), 8c is a servo motor (driving device), 8d is a load detector, and 17 is a molding chamber. , 19 is a lamp unit (heating device), 31 is a cooling member, 32 is a flange, 34 and 35 are cooling water pipes, 38 is a pressure flow control valve (cooling water stabilization means), 41 is a gas pipe, and 43 is a pressure flow rate. A control valve 58 represents a vacuum exhaust device.

  In FIG. 1, the upper mold 4 and the lower mold 11, the heat insulating cylinders 3, 10, the moving shaft 9, the lamp unit 19, and the thermocouple 27 are the same as those shown in FIG. Is omitted.

  In FIG. 1, the moving shaft 9 is directly connected to the servo motor 8c at the lower end. Similarly to the servo motor 8a previously shown in FIG. 4, the servo motor 8c controls the speed, torque and rotation amount according to a program preset by the control device 28a, and moves the moving shaft 9.

  A load detector 8d such as an S-shaped load cell is attached to the lower end of the fixed shaft 2a. The lower end of the load detector 8d is connected to the heat insulating cylinder 3 via the cooling member 31 and the flange 32.

  As shown in the plan view of FIG. 2, the cooling member 31 has a shape in which two portions of the disk are cut out, and has a cooling water passage 33 inside. One ends of cooling water pipes 34 and 35 are connected to the inlet and outlet of the cooling water flow path 33, respectively. As shown in FIG. 3, these cooling water pipes 34 and 35 are bent in a loop in the middle, and the other ends of these cooling water pipes 34 and 35 pass through the fixed shaft 2a up and down. It is connected to the lower end of each (not shown).

  An inlet cooling water pipe 36 and an outlet cooling water pipe 37 are connected to the upper end of the cooling water flow path in the fixed shaft 2a. The inlet cooling water pipe 36 is connected with a pressure flow control valve 38 for stabilizing the pressure and flow rate of the cooling water supplied to the cooling member 31 by suppressing fluctuations. The pressure flow control valve 38 can be configured to control the set value by the control device 28a. Instead of the pressure flow control valve 38, a buffer tank or the like can be used to suppress fluctuations in the pressure and flow rate of the cooling water.

  The flange 32 is inserted between the cooling member 31 and the heat insulating cylinder 3, and a gas supply path 40 is provided therein. As shown in FIG. 1, the gas supply path 40 has one end opened in the internal space of the heat insulating cylinder 3 and the other end opened in a notch portion of the cooling member 31 (see FIG. 2). One end of a gas pipe 41 bent in the middle of a loop is connected to the other end of the gas supply path 40 in the same manner as the cooling water pipes 34 and 35 shown in FIG. Is connected to the lower end of a gas supply passage (not shown) provided in parallel to the cooling water passage in the fixed shaft 2a. An inert gas supply pipe 42 is connected to the upper end of the gas supply path in the fixed shaft 2a.

  A pressure flow control valve 43 is connected to the inert gas supply pipe 42. The pressure flow control valve 43 operates in response to a command from the control device 28a, controls the supply stop of the inert gas and the supply pressure flow according to the program, and at the start of the supply of the inert gas, is a so-called soft start. The supply pressure and flow rate of the inert gas are increased by gradient control.

  In addition to the two cooling water passages (not shown) and one gas supply passage (not shown) described above, the fixed shaft 2a includes a cooling water circulation passage (for cooling the fixed shaft 2a) ( (Not shown) is provided.

  An upper plate 51 that is moved up and down by the driving device 50 is slidably attached to the fixed shaft 2a while maintaining an airtight state. As shown in FIG. 1, the upper plate 51 has a cylindrical shape that surrounds the outer periphery of the load detector 8 d and reaches the position where the lower end surrounds the outer periphery of the cooling member 31 when the molding chamber 17 described later is closed. A cooling chamber 52 is hermetically attached. The cooling chamber 52 is provided with a cooling water circulation path 53.

  At the lower end of the cooling chamber 52, a ring-shaped separation plate 54 that extends outward from the lower end is airtightly attached. A transparent quartz tube 16 is attached to the separation plate 54 so as to surround the upper mold 4 and the lower mold 11. The lower end of the transparent quartz tube 16 is hermetically pressed against the upper surface of the base ring 55 attached to the intermediate plate 1 a to form a molding chamber 17.

  The molding chamber 17 communicates with the internal space of the cooling chamber 52 above the flange 32 and the separation plate 54, and is formed so as to keep the internal space of the cooling chamber 52 equal to the pressure in the molding chamber 17. Has been. Hereinafter, it is assumed that the internal space of the cooling chamber 52 is a part of the molding chamber 17. That is, the molding chamber 17 is divided into a part surrounded by the transparent quartz tube 16 and accommodating the upper mold 4 and the lower mold 11 and a part surrounded by the cooling chamber 52 and accommodating the load detector 8d. A cooling water circulation path 56 is provided inside the base ring 55, and the lamp unit 19 is attached to the separation plate 54.

  The base ring 55 is provided with an exhaust port 57 and connects the molding chamber 17 to the vacuum exhaust device 58. Further, the upper plate 51 is provided with a gas supply path 59 for supplying an inert gas to a portion surrounded by the cooling chamber 52 and accommodating the load detector 8d, and the cooling chamber 52 is evacuated from the same portion. An exhaust port 60 for exhausting inert gas by the exhaust device 58 is provided.

Next, the operation procedure of this apparatus will be described. First, the inside of the molding chamber 17 is once evacuated and then purged with high-purity N ₂ gas. This prevents oxidation of the mold that occurs during continuous heating. After purging with N ₂ gas, the upper mold 4, the lower mold 11 and the glass material 30 are heated to a temperature range in which the lamp unit 19 can form the lamp. After reaching the predetermined temperature, the output of the lamp unit 19 is controlled by the control device 27a based on the output result of the thermocouple 27 so as to maintain the predetermined temperature. During the above, the lower mold and the upper mold are physically separated.

Here, vacuum forming will be described. This is a process performed to improve the transfer accuracy from the mold to the molded product. When forming in an N ₂ atmosphere as usual, an N ₂ gas reservoir is formed between the glass material 30 and the cores 6 and 13, and in the case of a convex lens, the gas reservoir is formed at the apex of the lens. In order to prevent this, the above vacuum forming is performed in vacuum. The evacuation is performed in a state where the glass material 30 is sandwiched between the upper and lower cores 6 and 13. Of course, at the time of molding, the output of the servo motor 8c is controlled so that a constant pressing force is applied based on information from the load detector 8d.

  However, during evacuation, due to a pressure difference between the inside and outside of the molding chamber, a force is applied to the lower shaft 9 upward and the upper shaft 2a (2) downward.

  Here, when the load detector 8b is in the position shown in FIG. 4, the load value detected by the lower shaft being pulled upward is smaller than the force actually applied to the glass material 30. .

  That is, the servo motor works to move the lower shaft 9 further upward.

  However, in reality, the glass material has a force to pull the lower shaft upward, so that an extra load is applied, and the glass material must work in the direction of lowering the shaft.

  However, if the load detector 8d is at the position shown in FIG. 1, the detector 8d detects the force that lifts the lower shaft upward, and guides the servo motor in the direction of lowering the load (lowering the shaft). Therefore, it is possible to measure and control the breath force applied to the glass material itself with higher accuracy than in the past.

In the case of vacuum forming, after the forming is completed, N ₂ gas is introduced into the forming chamber with the glass material 30 sandwiched between the upper and lower molds, and cooling and purging in the forming chamber are performed. At this time, the vertical shaft is pushed upward and downward, respectively. As a result, the BRESCA applied to the glass material must be increased, but if the detector is at the position 8b in FIG. 4, the measured value during cooling increases, and the servo motor is controlled in the direction of lowering the presser. End up.

  As a result, the force applied to the glass material is further reduced, resulting in molding that is completely different from reality.

However, the load detector 8d is easily affected by heat by being disposed in the molding chamber 17. However, this is because the separation plate 54, the flange 32 and the cooling member 31 suppress the influence of the infrared lamp 20, the cooling member 31 prevents heat transfer from the mold assembly 4, and the cooling chamber 52 further reduces the load detector 8 d. The temperature of the load detector 8d can be prevented from rising by suppressing the ambient temperature of the gas and further supplying an inert gas such as N ₂ gas from the gas supply path 59, thereby being sensitive to temperature. It is possible to achieve more precise pressing force control by using the highly sensitive load detector 8d.

  Note that the cooling water pipes 34 and 35 and the gas pipe 41 can be prevented from adversely affecting the load measurement of the load detector 8d by bending the middle in a loop.

  Further, changes in the pressure and flow rate of the cooling water supplied and discharged to the cooling member 31 through the cooling water pipes 34 and 35 adversely affect the output of the load detector 8d, and further, through the gas pipe 41, the flange 32 and the like, the molding chamber. If the supply of the inert gas supplied to 17 is abrupt, this also adversely affects the output of the load detector 8d. These are stabilized by suppressing fluctuations in the pressure and flow rate of the cooling water supplied to the cooling member 31 by the pressure flow control valve 38 provided in the inlet cooling water pipe 36, and further provided in the inert gas supply pipe 42. This can be solved by controlling the supply pressure and flow rate of the inert gas by the flow rate control valve 43 and so-called soft start.

  In the example shown in FIG. 1, the load detector 8d is inserted between the fixed shaft 2a and the upper mold 4 and disposed in the molding chamber 17, but the present invention is limited to such a form. Instead, various modifications may be made such that the load detector 8d may be inserted between the moving shaft 9 and the lower mold 11 and disposed in the molding chamber 17, for example.

The schematic block diagram which shows the example of the glass forming apparatus based on this invention. The top view of the cooling member in FIG. The left view of the cooling water piping in FIG. The schematic block diagram which shows the conventional glass forming apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Device frame, 2, 2a ... Fixed axis | shaft 3, 10, ... Thermal insulation cylinder, 4 ... Upper mold | type (fixed mold | type), 11 ... Lower mold | type (movable type), 5, 12 ... Die plate, 6, 13 ... Core, 7 ... Fixed die, 14 ... Moving die, 8a, 8c ... Servo motor, 8b, 8d ... Load detector, 9 ... -Moving shaft, 15 ... upper plate, 16 ... transparent quartz tube, 17 ... molding chamber, 18 ... outer cylinder, 19 ... lamp unit (heating device), 20 ... infrared lamp , 21 ... reflection mirror, 22 ... water-cooled pipe, 23, 24, 25 ... gas supply path, 26 ... exhaust port, 27 ... thermocouple, 28, 28a ... control device, 30 ... Glass material, 31 ... Cooling member, 32 ... Flange, 33 ... Cooling water flow path, 34, 35 ... Cooling water Pipe, 36 ... Inlet cooling water pipe, 37 ... Outlet cooling water pipe, 38 ... Pressure flow control valve (cooling water stabilization means), 40 ... Gas supply path, 41 ... Gas pipe 42 ... Inert gas supply piping, 43 ... Pressure flow control valve, 50 ... Drive device, 51 ... Upper plate, 52 ... Cooling chamber, 53 ... Cooling water circulation path, 54 ... Separation plate, 55 ... Base ring, 56 ... Cooling water circulation path, 57 ... Exhaust port, 58 ... Vacuum exhaust device, 59 ... Gas supply channel, 60 ... Exhaust port .

Claims (10)

A molding chamber;
A stationary mold and a movable mold arranged to face each other in the molding chamber;
A fixed shaft that supports the fixed mold from the back side;
A moving shaft that supports the movable mold from the back side;
A drive device for moving the moving axis with respect to the fixed mold by speed, load or position control according to a preset program;
A heating device for heating the stationary mold, the movable mold and the glass material put between them;
Gas supply means for supplying an inert gas into the molding chamber;
An evacuation device for depressurizing the molding chamber;
A load detector for detecting a pressing force acting between the fixed mold and the movable mold;
In a glass forming apparatus comprising:
The glass forming apparatus, wherein the load detector is inserted between either the fixed shaft and the fixed mold or between the movable shaft and the movable mold, and is disposed in the molding chamber.   The glass forming apparatus according to claim 1, wherein a cooling member in which a path through which cooling water circulates is formed is inserted between the fixed mold or the movable mold and the load detector.   A cooling water pipe is provided for introducing the cooling water from the cooling water flow path provided in the fixed shaft or the moving shaft into the cooling member, and the cooling water pipe is formed in a loop shape in the middle. The glass forming apparatus according to claim 2, wherein the glass forming apparatus is formed so as to be able to absorb a variation in a distance between the fixed shaft or the moving shaft and the cooling member.   The glass forming apparatus according to claim 3, further comprising cooling water stabilizing means for suppressing fluctuations in the supply pressure and flow rate of the cooling water. A flange that is inserted between the fixed type or the movable type and the cooling member and in which a path through which an inert gas flows is formed;
A gas pipe for introducing an inert gas into the flange from a gas flow path provided in the fixed shaft or the moving shaft;
The gas supply means introduces an inert gas into the molding chamber through the gas flow path provided in the fixed shaft or the moving shaft, the gas pipe, and the path inside the flange. It is comprised by these, The glass forming apparatus of Claim 2 characterized by the above-mentioned.   6. The gas pipe according to claim 5, wherein a part of the gas pipe is formed in a loop shape so as to absorb a variation in a distance between the fixed shaft or the moving shaft and the cooling member. Glass forming equipment.   The glass forming apparatus according to claim 6, further comprising a pressure / flow rate control valve for increasing a supply pressure and a flow rate of the inert gas supplied into the cooling member by gradient control.   The molding chamber is divided into a first part that accommodates the fixed mold and the movable mold and a second part that accommodates the load detector, and the heating device is disposed only in the first part. The glass forming apparatus according to claim 1, wherein   The glass forming apparatus according to claim 8, wherein the forming chamber is configured such that a wall surface of the second portion can be cooled.   The glass forming apparatus according to claim 8, wherein the first portion and the second portion of the forming chamber are configured to be supplied with an inert gas separately.

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