Heating barrel insulation method and device for injection molding machine

Abstract

To ensure good responsiveness during temperature control while maintaining heating and cooling functions including good insulation to improve mass productivity by shortening a molding cycle and improve yield rate by reducing defective products.SOLUTION: A heating barrel insulation device includes: a heat insulating layer part 4 that is attached to an outer periphery 3f of a heating part 3 and has a vacuum controlled space 5 formed therein; vacuum means 6 for enabling the vacuum controlled space 5 to be evacuated; sealing means 7 for sealing the vacuum controlled space 5; and sealing release means 8 for releasing the sealing of the vacuum controlled space 5. During temperature control of a heating barrel 2, the sealing means 7 or the sealing release means 8 is switched and controlled in accordance with a state of the temperature control, and at least the vacuum controlled space 5 is switched to a vacuum insulation mode Mv or a vacuum insulation release mode Mr.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for insulating a heater barrel of an injection molding machine that is suitable for use in insulating the heater barrel of an injection molding machine, and a heater barrel insulating device used for carrying out said method. [Background technology]

[0002] In general, an injection unit that constitutes an injection molding machine is equipped with a heating barrel that plasticizes the resin material that is fed in, and since the temperature control of this unit requires accuracy and responsiveness, the heating barrel is equipped with a heating section equipped with a band heater or the like on its outer periphery, and is also equipped with a cooling section equipped with a jacket or the like that has an air-cooling function. Known examples of injection molding machines equipped with such heating and cooling means include the temperature control device for an injection molding machine described in Patent Document 1 and the injection unit described in Patent Document 2.

[0003] The temperature control device of the injection molding machine in Patent Document 1 aims to realize a temperature control device that controls the cooling function and heating function in a coordinated manner, performs highly stable control that avoids hunting phenomena and the like, and is excellent in energy saving while ensuring high control accuracy. The device is equipped with a molding machine controller that detects the heating temperature of a specific part in the heating barrel using a temperature sensor, and controls the heating section that heats the specific part and the cooling section that cools the specific part so that the detected temperature becomes a preset temperature. The device is also equipped with a PID control system that calculates the deviation value between the detected temperature and the set temperature, performs PID control so that this deviation value becomes zero, and outputs only one of the relatively larger operation amounts, namely, a heating operation amount generated from an I operation output, a D operation output, the deviation value, and a heating side proportional band and used to control the heating section, and a cooling operation amount generated from an I operation output, a D operation output, the deviation value, and a cooling side proportional band and used to control the cooling section, to the corresponding heating section or cooling section.

[0004] In addition, the injection device in Patent Document 2 is an injection device in which a heating cylinder is divided into a plurality of zones in the axial direction, and each zone is equipped with a plurality of band heaters wrapped around the outer periphery of the heating cylinder, a plurality of insulating covers provided on the outside of the band heaters, and a cooling means for independently supplying air from the outside to each insulating cover, so that each zone is independently temperature controlled. The injection device is equipped with a predetermined suction means and a Stirling engine, and the suction means is adapted to suck air from each insulating cover, and the Stirling engine is configured to be driven using the sucked air as a heat source to generate electricity. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-083867 A [Patent Document 2] JP 2016-112775 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the conventional injection molding machine equipped with the above-mentioned heating and cooling means has the following problems to be solved.

[0007] That is, in this type of injection molding machine, temperature control is performed by switching between a heating means and a cooling means, so basically, it is necessary to switch between the heating means and the cooling means and to directly transmit the heating temperature from the heating means and the cooling temperature from the cooling means to the heating barrel to perform temperature control of the heating side and temperature control of the cooling side.

[0008] On the other hand, since the target temperature for the heating cylinder must be maintained at a high temperature of several hundred degrees Celsius, not only the capacity of the heating means but also the heat insulation capacity of the heat retention means, i.e., the insulation means, is important. Usually, an insulation cover or the like is used as the insulation means, and if an insulation cover is attached to increase the insulation, it works advantageously during heating (when the temperature rises), but on the other hand, as a side effect, the responsiveness when switching from heating to lowering the temperature is greatly reduced. In particular, if the high temperature continues for a long time, it can cause molding defects such as resin burning.

[0009] As described above, in an injection molding machine equipped with a conventional heating / cooling means, it is not easy to improve responsiveness during temperature control while maintaining good heating and cooling functions, and there has been a demand for an improvement in the heating / cooling means that can improve both of these capabilities, i.e., the insulation capability and the ability to provide high responsiveness in temperature control.

[0010] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a method and device for insulating a heater barrel of an injection molding machine which solves the problems existing in the background art. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, the heating barrel insulation method of the injection molding machine 1 according to the present invention is characterized in that, when insulating at least a heating barrel 2 equipped with a heating section 3, a heat insulating layer section 4 is provided in advance on an outer periphery 3f of the heating section 3 and has a vacuum-controlled space 5 formed therein, a vacuum means 6 for making the vacuum-controlled space 5 evacuable, a sealing means 7 for making the vacuum-controlled space 5 sealable, and a sealing release means 8 for releasing the sealing of the vacuum-controlled space 5, and during temperature control of the heating barrel 2, the sealing means 7 or the sealing release means 8 are switched in response to the state of temperature control to switch at least the vacuum-controlled space 5 to a vacuum insulation mode Mv or a vacuum insulation release mode Mr.

[0012] In addition, in order to solve the above-mentioned problems, the heated barrel insulation device 10 of the injection molding machine 1 of the present invention is characterized in that, when configuring a heated barrel insulation device that insulates at least a heated barrel 2 equipped with a heating section 3, it is provided with an insulation layer section 4 that is attached to the outer periphery 3f of the heated section 3 and has a vacuum controlled space 5 formed therein, a vacuum means 6 that makes the vacuum controlled space 5 vacuumable, a sealing means 7 that makes the vacuum controlled space 5 sealable, a sealing release means 8 that releases the sealing of the vacuum controlled space 5, and a molding machine controller 11 that switches and controls the sealing means 7 or the sealing release means 8 in accordance with the state of the temperature control during temperature control of the heated barrel 2, and switches at least the vacuum controlled space 5 to a vacuum insulation mode Mv or a vacuum insulation release mode Mr.

[0013] In this case, according to a preferred embodiment of the invention, when implementing the heating barrel insulation method, during heating control in which the heating unit 3 is turned ON to heat the heating barrel 2, the mode can be switched to the vacuum insulation mode Mv, and during cooling control in which the heating unit 3 is turned OFF to release the heating of the heating barrel 2, the mode can be switched to the vacuum insulation release mode Mr. At this time, during cooling control, the inside of the vacuum control space 5 can be sucked by the vacuum means 6, and the outside air Ao can be circulated through the vacuum control space 5. On the other hand, when configuring the heating barrel insulation device 10, the vacuum means 6 can be a vacuum pump 6p that sucks the inside of the vacuum control space 5. In addition, the heating unit 3 can be a band heater 3b..., and the insulation layer part 4 can be configured in a band shape that covers all or part of the outer circumferential surface 3bf... of the band heater 3b... and has a ring-shaped vacuum control space 5 inside. Furthermore, the sealing means 7 can be a check valve 7v connected between the vacuum-controlled space 5 and the vacuum means 6, and the sealing release means 8 can be an on-off valve 8v connected between the vacuum-controlled space 5 and the atmosphere Ao. Effect of the Invention

[0014] According to the heater barrel insulating method and heater barrel insulating device 10 of the injection molding machine M according to the present invention, the following remarkable effects are obtained.

[0015] (1) The heat insulating layer 4 is attached to the outer periphery 3f of the heating section 3 and has a vacuum controlled space 5 formed therein, a vacuum means 6 for making the vacuum controlled space 5 evacuable, a sealing means 7 for making the vacuum controlled space 5 sealable, and a sealing release means 8 for releasing the sealing of the vacuum controlled space 5. The sealing means 7 or the sealing release means 8 are switched and controlled in response to the state of temperature control to switch at least the vacuum controlled space 5 to the vacuum insulation mode Mv or the vacuum insulation release mode Mr, so that good responsiveness during temperature control can be ensured while maintaining the heating function and cooling function including good heat insulation. This allows for improved mass productivity by shortening the molding cycle and improved yield rate by reducing defective products.

[0016] (2) In a preferred embodiment, when implementing the heating barrel insulation method, during heating control in which the heating unit 3 is turned ON to heat the heating barrel 2, the mode is switched to the vacuum insulation mode Mv, and during cooling control in which the heating unit 3 is turned OFF to release the heating of the heating barrel 2, the mode is switched to the vacuum insulation release mode Mr. This can be utilized for the normal temperature control sequence related to the temperature control of the heating barrel 2, thereby enabling optimal temperature control of the heating barrel 2 to be realized.

[0017] (3) In a preferred embodiment, during cooling control, the inside of the vacuum-controlled space 5 is suctioned by the vacuum means 6 and outside air Ao is circulated through the vacuum-controlled space 5, thereby achieving a cooling function through the air-cooling effect.

[0018] (4) In a preferred embodiment, when constructing the heating barrel insulation device 10, if a vacuum pump 6p that sucks the inside of the vacuum controlled space 5 is used as the vacuum means 6, the suction action on the vacuum controlled space 5 can be reliably achieved, so that the mode can be easily switched to the vacuum insulation mode Mv. Furthermore, when switched to the vacuum insulation release mode Mr, the mode can also be used as a blower function for circulating the outside air Ao, so that the air cooling function can be easily achieved.

[0019] (5) In a preferred embodiment, by using a band heater 3b in the heating section 3, a heating section 3 similar to a conventional heating section using a band heater 3b can be constructed. This can be easily implemented without making any particular changes to the configuration or layout of the heating section 3.

[0020] (6) In a preferred embodiment, the insulating layer 4 is configured in a band shape that covers all or part of the outer peripheral surface 3bf of the band heater 3b and has a ring-shaped vacuum control space 5 therein. This can be implemented without significantly changing the overall radial size of the heating barrel 2, thereby avoiding unnecessary complication and increase in size of the injection molding machine 1.

[0021] (7) In a preferred embodiment, the sealing means 7 includes a check valve 7v connected between the vacuum control space 5 and the vacuum means 6. This makes it possible to configure the sealing means 7 simply by adding the check valve 7v, thereby contributing to easier implementation and lower costs of the sealing means 7.

[0022] (8) In a preferred embodiment, the seal releasing means 8 includes an on-off valve 8v connected between the vacuum-controlled space 5 and the atmosphere Ao. This can be achieved by simply adding the on-off valve 8v to the seal releasing means 8, which can contribute to facilitating the implementation of the seal releasing means 8 and reducing costs. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of an entire control system including a cross-sectional side view of an injection unit in an injection molding machine equipped with a heater barrel insulation device according to a preferred embodiment of the present invention; [Diagram 2] Overall system diagram of the heating barrel insulation device, [Diagram 3] FIG. 2 is a sectional front view showing an outline of the state in which the heating barrel insulation device is attached to the heating barrel; [Figure 4] FIG. 2 is a cross-sectional side view showing an outline of the state in which the heating barrel insulation device is attached to the heating barrel; [Diagram 5] FIG. 2 is an external perspective view showing each component of the heating barrel insulation device; [Figure 6]A flowchart for sequentially explaining a heater barrel insulation method according to a preferred embodiment of the present invention. [Figure 7] FIG. 2 is an explanatory diagram of the operation of the vacuum insulation mode when carrying out the heating barrel insulation method; [Figure 8] FIG. 2 is an explanatory diagram of the operation of the vacuum insulation release mode when carrying out the heating barrel insulation method; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0025] First, an outline of an injection molding machine 1 equipped with a heater barrel insulation device 10 according to this embodiment will be described with reference to FIG.

[0026] 1, 1i denotes an injection device, and this injection device 1i and a mold clamping device (not shown) constitute an injection molding machine 1. The injection device 1i includes a heating barrel 2, which includes an injection nozzle 2n at its front end, and a rear end of the heating barrel 2 is connected to a material supplying section 21 including a hopper 21h for feeding a resin material into the heating barrel 2. A screw 22 is inserted into the heating barrel 2, and a rear end of the screw 22 extends rearward from the material supplying section 21 to be connected to a screw driving section 23 (not shown in detail) for driving the screw 22 to rotate and move forward and backward.

[0027] The outer peripheral surface 2f of the heating cylinder 2 and the outer peripheral surface 2nf of the injection nozzle 2n are provided with a plurality of heating parts 3... arranged in sequence along the axial direction Fs. That is, five heating parts 3... are provided, which are respectively attached to the injection nozzle 2n, the front part of the heating cylinder 2, the middle part of the heating cylinder 2, the rear part of the heating cylinder 2, and the rearmost part of the heating cylinder 2. Each heating part 3... uses a band heater 3b... that has a heating element built in and is wrapped around the outer peripheral surface 2f... and 2nf. In this way, if the band heater 3b... is used for the heating part 3, a heating part 3 similar to the conventional one using the band heater 3b... can be configured, so that it can be easily implemented without particularly changing the configuration or layout of the heating part 3 side. Meanwhile, a heat insulating layer part 4... is attached to the outer peripheral surface 3f... of each heating part 3.... Each heat insulating layer part 4... constitutes the heating barrel insulation device 10 according to this embodiment, which is the main part of the present invention.

[0028] Next, the configuration of the heater barrel insulation device 10 according to this embodiment will be specifically described with reference to Figs.

[0029] As shown in Figs. 1 to 3, the above-mentioned heating barrel insulation device 10 includes a total of five heat insulating layers 4... attached to the outer circumferential surface 3f... of each heating section 3.... The heat insulating layer 4 (the same applies to the other heat insulating layers 4...) covers all or part of the outer circumferential surface 3bf of the band heater 3b and is configured in a band shape having a ring-shaped vacuum control space 5 inside. By configuring the heat insulating layer 4 in this way, it can be implemented without significantly changing the overall radial size of the heating barrel 2, so that unnecessary complication and size increase of the injection molding machine 1 can be avoided.

[0030] 5(a)-(c) show external perspective views of each component that constitutes the thermal insulation layer 4. Note that (d) shows the band heater 3b. (a) shows the outer panel portion 25 that constitutes the outermost portion of the thermal insulation layer 4, (b) shows the vacuum-controlled space forming panel 26 that is disposed inside the outer panel portion 25, and (c) shows the inner panel portion 27 that is disposed inside the vacuum-controlled space forming panel 26 and abuts against the outer peripheral surface 3bf of the band heater 3b.

[0031] In this case, the outer panel portion 25, the vacuum-controlled space forming panel 26, and the inner panel portion 27 can each be formed using a single stainless steel panel having a thickness of about 1-2 mm. The outer panel portion 25 is formed as a single rectangular piece, and a pair of round-bar-shaped bolt insertion rods 25s, 25t are fixed to both ends in the longitudinal direction (circumferential direction) by welding or the like, and a first connecting pipe portion 25i and a second connecting pipe portion 25o, which protrude outward from the outer peripheral surface and communicate with the inner peripheral surface, are fixed near the bolt insertion rods 25s, 25t. The vacuum-controlled space forming panel 26 is formed as a rectangular frame as a whole, and near one end in the longitudinal direction (circumferential direction), there are formed lead-out holes 26x... through which a plurality of cable lead-out pipes 3bx... (see (d)) for leading out the cables of the band heater 3b are inserted. The inner panel portion 27 is formed as a single rectangular piece as a whole.

[0032] The outer panel portion 25, the vacuum-controlled space forming panel 26, and the inner panel portion 27 are laminated as shown in Figures 3 and 4. This forms a panel-like heat insulating layer portion 4, and inside the panel portion 25, a ring-shaped hollow air jacket that is sealed except for the first connecting pipe portion 25i and the second connecting pipe portion 25o, i.e., the vacuum-controlled space 5, is formed.

[0033] Since the heat insulating layer 4 has a vacuum control space 5 inside, it can be realized in various forms. For example, the inner surface side (inner panel portion 27 side) of the heat insulating layer 4 is attached to the outer peripheral portion 3f of the heating portion 3 attached to the heating cylinder 2, so that the inner diameter of the inner surface side of the heat insulating layer 4 is formed to be a size that fits this outer peripheral portion 3f, and thus the heat insulating layer 4 may be assembled integrally in advance by welding or the like, or the outer panel portion 25 and the vacuum control space forming panel 26, or the vacuum control space forming panel 26 and the inner panel portion 27 may be integrally formed. In addition, when attaching to the outer peripheral portion 3f of the heating portion 3, the inner panel portion 27, the vacuum control space forming panel 26, and the outer panel portion 25 may be stacked in this order, and the bolt insertion rods 25s and 25t of the outer panel portion 25 may be tightened and fixed by bolts and nuts B.... In this case, packing or the like may be interposed as necessary to prevent air leakage.

[0034] Next, the configuration of the heater barrel insulation device 10 other than the insulation layer portion 4 will be described mainly with reference to FIG. 1 and FIG.

[0035] 2, one end of check valves 7v constituting the sealing means 7 is connected to the second connecting pipes 25o of each of the heat insulating layers 4, and the other ends of the check valves 7v are joined together to be connected to the suction port of the vacuum pump 6p constituting the vacuum means 6. Reference numeral 31 denotes a motor that drives the vacuum pump 6p.

[0036] In this way, by using a check valve 7v connected between the vacuum controlled space 5 and the vacuum means 6 as the sealing means 7, the sealing means 7 can be constructed simply by adding the check valve 7v, which contributes to easier implementation and lower costs related to the sealing means 7. Furthermore, by using a vacuum pump 6p that sucks the inside of the vacuum controlled space 5 as the vacuum means 6, the suction action on the vacuum controlled space 5 can be reliably achieved, making it easy to switch to the vacuum insulation mode Mv. Furthermore, when switching to the vacuum insulation release mode Mr, it can also be used as a blower function to circulate the outside air Ao, making it easy to realize the air cooling function.

[0037] 2, one end of an on-off valve 8v using a solenoid valve constituting the seal releasing means 8 is connected to the first connecting pipe portion 25i of the thermal insulation layer 4 (the same is true for the other thermal insulation layer portions 4, etc.), and the other end of the on-off valve 8v is opened to the atmosphere Ao. As a result, the on-off valve 8v is connected between the vacuum-controlled space 5 and the atmosphere Ao. In this way, if the on-off valve 8v is used as the seal releasing means 8, the seal releasing means 8 can be constructed simply by adding the on-off valve 8v, which contributes to easier implementation and lower costs.

[0038] The cable of the band heater 3b constituting the heating unit 3 is led out through cable lead-out pipes 3bx... and connected to the output side of the power supply unit 32. 33... indicate temperature sensors (thermocouples) that detect the temperatures of each part of the heating barrel 2 including the injection nozzle 2n, i.e., the injection nozzle and the front, middle, rear and rearmost parts of the heating barrel.

[0039] The power supply unit 32, the vacuum pump 6p, and each on-off valve 8v are connected to an output port of the molding machine controller 11, and each temperature sensor 33 is connected to a sensor input port of the molding machine controller 11. The molding machine controller 11 basically includes a controller body having built-in hardware such as a CPU, and also includes an internal memory such as a hard disk managed by the controller body. Therefore, the molding machine controller 11 is configured as a computer system and has a function of controlling the entire injection molding machine 1. The molding machine controller 11 also includes a sequence control program for executing the heating barrel insulation method according to this embodiment, and also includes peripheral devices such as a display (not shown).

[0040] Next, the heater barrel insulation method according to this embodiment will be described mainly according to the formula chart shown in FIG. 6 with reference to FIGS.

[0041] Assume that the injection molding machine 1 is currently in a stopped state (step S1). In this state, the vacuum pump 6p and the band heaters 3b are in the OFF position, and the on-off valve 8v is in the closed position Sc. In this state, it is assumed that a heating command is output from the molding machine controller 11 (step S2).

[0042] As a result, the vacuum pump 6p is turned ON and the band heaters 3b are turned ON (steps S3 and S4). As a result, as shown in FIG. 7, the air A inside the vacuum-controlled space 5 is sucked by the vacuum pump 6p, and the inside of the vacuum-controlled space 5 is switched to the vacuum insulation mode Mv in which the vacuum control space 5 is in a vacuum state. At this time, when a predetermined vacuum state is reached, the vacuum pump 6p may be turned OFF as necessary. Even in this case, the check valves 7v are connected to the second connecting pipes 25o, so that the vacuum-controlled space 5 is kept sealed. That is, the first connecting pipes 25i are kept closed by the opening / closing valves 8v, so that the vacuum state of the vacuum-controlled space 5 is maintained.

[0043] Furthermore, the heating barrel 2 is heated by the ON position of the band heaters 3b, and the detected temperatures of the temperature sensors 33 are provided to the molding machine controller 11, so that the molding machine controller 11 monitors the temperature rise state of the heating barrel 2 (step S5). Then, when the detected temperature reaches a preset predetermined temperature target value, a temperature control process is executed by PID control (feedback control) for the temperature to maintain the temperature target value (steps S6 and S7).

[0044] On the other hand, once the temperature has stabilized, a predetermined molding process, i.e., production process, can be carried out. When the production process is completed, necessary termination processes such as stopping the operation of the injection molding machine 1 are carried out (steps S8 and S9).

[0045] On the other hand, assume that during production processing, the temperature of the heating barrel 2 rises excessively, and a cooling command is output from the molding machine controller 11 (steps S8, S10). As a result, the on-off valve 8v is controlled to switch to the open position So, and the band heaters 3b... are controlled to switch to the OFF position (steps S11, S12). Also, if the vacuum pump 6p is OFF, it is switched to ON (step S13).

[0046] 8, the outside air Ao flows into the vacuum-controlled space 5 through the on-off valve 8v, and the vacuum-controlled space 5 is switched to the vacuum insulation release mode Mr. Moreover, the inside of the vacuum-controlled space 5 is sucked by the vacuum pump 6p, so that the outside air Ao flows inside the vacuum-controlled space 5. That is, a cooling function by air-cooling effect can be realized.

[0047] In this way, when implementing the heating barrel insulation method, during heating control when the heating unit 3 is turned ON to heat the heating barrel 2, control is performed to switch to the vacuum insulation mode Mv, and during cooling control when the heating unit 3 is turned OFF to release the heating of the heating barrel 2, control is performed to switch to the vacuum insulation release mode Mr. This can be utilized for the normal temperature control sequence related to the temperature control of the heating barrel 2, thereby achieving optimal temperature control for the heating barrel 2.

[0048] Therefore, according to the heating barrel insulation method (heating barrel insulation device 10) of the injection molding machine 1 according to this embodiment, the insulation layer part 4, which is attached to the outer periphery 3f of the heating part 3 and has a vacuum control space 5 formed therein, the vacuum means 6 for making the vacuum control space 5 vacuum, the sealing means 7 for making the vacuum control space 5 sealable, and the sealing release means 8 for releasing the sealing of the vacuum control space 5 are provided, and the sealing means 7 or the sealing release means 8 are switched and controlled according to the state of the temperature control, and at least the vacuum control space 5 is switched to the vacuum insulation mode Mv or the vacuum insulation release mode Mr, so that good responsiveness during temperature control can be ensured while maintaining the heating function and cooling function including good insulation function. This allows for the improvement of mass productivity by shortening the molding cycle and the improvement of the yield rate by reducing defective products.

[0049] Although the preferred embodiment has been described in detail above, the present invention is not limited to such an embodiment, and the detailed configuration, shape, material, quantity, numerical values, etc. can be changed, added, or deleted as desired without departing from the gist of the present invention.

[0050] For example, in the embodiment, the case where the present invention is applied to the heating cylinder 2 equipped with the heating unit 3 is illustrated, but the present invention can be applied to the heating cylinder 2 equipped with both the heating unit 3 and the cooling unit. In this case, during cooling control, the vacuum means 6 may be stopped and only the vacuum state may be released. That is, only the vacuum state of the vacuum control space 5 may be released, and it is not necessary to circulate the outside air Ao through the vacuum control space 5. Furthermore, during cooling control, the vacuum pump 6p may not be used, and a blowing means using a fan or the like may be used. In addition, when implementing the heating cylinder insulation method, it is desirable to control the switching to the vacuum insulation mode Mv during heating control in which the heating unit 3 is turned ON to heat the heating cylinder 2, and to control the switching to the vacuum insulation release mode Mr during cooling control in which the heating unit 3 is turned OFF to release the heating of the heating cylinder 2, but it is also possible to use only the vacuum insulation mode Mv or only the vacuum insulation release mode Mr. On the other hand, various vacuum pumps 6p can be used for the vacuum means 6, and can be replaced with means having similar functions. Furthermore, although a check valve 7v is used in the sealing means 7 and an on-off valve 8v is used in the sealing release means 8, a control valve may be connected if necessary so that the vacuum level can be appropriately adjusted. [Industrial Applicability]

[0051] The heater barrel insulating method and heater barrel insulating device according to the present invention can be used to insulate heater barrels provided in various injection molding machines. [Explanation of symbols]

[0052] 1: injection molding machine, 2: heating cylinder, 3: heating section, 3f: outer periphery of heating section, 3b: band heater, 3bf: outer periphery of band heater, 4: heat insulating layer, 5: vacuum control space, 6: vacuum means, 6p: vacuum pump, 7: sealing means, 7v: check valve, 8: sealing release means, 8v: opening and closing valve, 10: heating cylinder heat insulating device, 11: molding machine controller, Mv: vacuum insulation mode, Mr: vacuum insulation release mode, Ao: outside air

Claims

1. This method of insulating a heater barrel of an injection molding machine for insulating at least a heater barrel equipped with a heater section comprises the steps of: providing an insulating layer section attached to the outer periphery of the heater section and forming a vacuum-controlled space therein; vacuum means for making the vacuum-controlled space vacuum-capable; sealing means for making the vacuum-controlled space sealable; and sealing release means for releasing the seal of the vacuum-controlled space; and during temperature control of the heater barrel, switching control of the sealing means or the sealing release means is performed in accordance with the state of temperature control, thereby switching at least the vacuum-controlled space to a vacuum insulation mode or a vacuum insulation release mode.

2. 2. The method for insulating a heater barrel of an injection molding machine according to claim 1, wherein during heating control in which the heating unit is turned ON to heat the heater barrel, control is performed to switch to the vacuum insulation mode, and during cooling control in which the heating unit is turned OFF to release the heating of the heater barrel, control is performed to switch to the vacuum insulation release mode.

3. 3. The method for insulating a heater barrel of an injection molding machine according to claim 2, wherein, during the cooling control, the inside of the vacuum controlled space is sucked by the vacuum means and outside air is circulated through the vacuum controlled space.

4. A heater barrel insulation device for an injection molding machine that insulates at least a heater barrel equipped with a heating section, comprising: an insulation layer section attached to the outer periphery of the heater section and forming a vacuum-controlled space inside; a vacuum means for making the vacuum-controlled space vacuum-capable; a sealing means for making the vacuum-controlled space sealable; a sealing release means for releasing the seal of the vacuum-controlled space; and a molding machine controller that, during temperature control of the heater barrel, switches and controls the sealing means or the sealing release means in response to the state of the temperature control, and switches at least the vacuum-controlled space to a vacuum insulation mode or a vacuum insulation release mode.

5. 5. The heater barrel heat insulating device for an injection molding machine according to claim 4, wherein the vacuum means is a vacuum pump for sucking the inside of the vacuum control space.

6. 5. The heater barrel heat insulating device for an injection molding machine according to claim 4, wherein the heating section uses a band heater.

7. 7. The heater barrel insulation device of an injection molding machine according to claim 6, wherein the insulation layer portion is configured in a band shape covering all or part of the outer circumferential surface of the band heater and having a ring-shaped vacuum control space therein.

8. 5. The heater barrel heat insulating device for an injection molding machine according to claim 4, wherein said sealing means comprises a check valve connected between said vacuum control space and said vacuum means.

9. 5. The heater barrel heat insulating device for an injection molding machine according to claim 4, wherein said sealing release means is an opening and closing valve connected between said vacuum controlled space and the atmosphere.

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