Support system and method for removing end cap

Abstract

To reduce a torque required to loosen a bolt as a fastener.SOLUTION: A support system (10A, 10B) includes: a temperature detection section (20) that detects a temperature of one or both of an end cap (3) and a fastener (B); and a control section (40) that suggests removing the fastener (B) if detected temperatures (T1, T2) detected by the temperature detection section (20) satisfy a predetermined work start temperature (Te) condition.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method of removing an end cap that closes an open end provided with a nozzle of a heating cylinder from the heating cylinder in an injection device.

Background Art

[0002] In an injection device, a bolt as a fastener for fixing an end cap to a heating cylinder is tightened with a large torque so that the molten resin inside the heating cylinder does not leak to the outside under the injection pressure in the injection process. Therefore, when removing the end cap from the heating cylinder, it is necessary to apply a large torque to the bolt, and the operation of applying a large torque is likely to be unstable. Therefore, in consideration of safety, it is desired to reduce the torque applied.

[0003] Patent Document 1 proposes a method for attaching and detaching an end cap from a heating cylinder. In this proposal, the end cap is formed into a semi-circular shape divided into two approximately at the center, and the end cap is fixed through a seat plate in which one end of each is pivotally attached so as to be openable and closable.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the proposal of Patent Document 1, since the end cap can be attached to and detached from the heating cylinder without removing all the bolts fixing the end cap to the heating cylinder, the labor for attaching and detaching the end cap can be reduced. However, also in Patent Document 1, it is still necessary to apply a large torque to loosen the bolt. From the above, an object of the present invention is to reduce the torque required to loosen a fastener, typically a bolt.

Means for Solving the Problem

[0006] The present invention is an assistance system that functions when removing an end cap fixed by a fastener from a heating cylinder of an injection device, a temperature detection unit that detects the temperature of one or both of the end cap and the fastener, and a control unit that suggests the removal of the fastener if the detected temperature detected by the temperature detection unit satisfies the condition of a predetermined work start temperature.

[0007] The assistance system of the present invention preferably includes a cooling unit having a cooling unit provided on the end cap and a supply source that supplies a cooling medium to the cooling unit, and the control unit preferably operates the supply source so that the cooling medium is supplied to the cooling unit if the detected temperature satisfies the condition of a predetermined cooling start temperature, and executes cooling of the end cap by the cooling unit.

[0008] Preferably, a fastener heater inserted into the fastener is provided, and the control unit preferably instructs heating of the fastener heater while the cooling of the end cap is being executed.

[0009] The control unit preferably sets a work start temperature higher than the heat distortion temperature of the residual resin left in the heating cylinder and compares it with the detected temperature.

[0010] The control unit preferably sets the work start temperature within a temperature range of ±20°C with respect to the melting point or flow start point of a partial component or the main component of the residual resin.

[0011] The control unit preferably If the temperature difference between the detected temperature T1 of the end cap and the detected temperature T2 of the fastener by the temperature detection unit satisfies the condition of a predetermined operation start temperature difference, it suggests the removal of the fastener. Comprising a fastener heater inserted into the fastener, The control unit, After instructing the heating of the fastener heater, if the temperature difference (T2 - T1) between the detected temperature T1 and the detected temperature T2 satisfies the condition of a predetermined operation start temperature difference, it suggests the removal of the fastener.

[0012] The present invention is a method for removing an end cap fixed by a fastener from a heating cylinder of an injection device, A first step of detecting the temperature of one or both of the end cap and the heating cylinder, If the detected temperature detected in the first step satisfies the condition of a predetermined operation start temperature, a second step of performing an operation of loosening the fastener is provided.

Effect of the Invention

[0013] According to the support system of the present invention, if the detected temperature at one or both of the end cap and the fastener satisfies the condition of a predetermined operation start temperature, it suggests the removal of the fastener. Therefore, according to the support system of the present invention, in the subsequent operation, the torque applied to the fastener when loosening the fastener can be reduced.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. This embodiment relates to a method for removing an end cap that seals an opening end where a nozzle of a heating cylinder is provided from the heating cylinder and a support system for smoothly performing this method. The removal method according to this embodiment aims to reduce the torque applied to a bolt when removing an end cap fixed to the heating cylinder by a bolt, which is an example of a fastener. This embodiment includes two, the first embodiment and the second embodiment. First, after explaining the schematic configuration of the end cap including the heating cylinder and the reason why the applied torque can be reduced, which are common to the two embodiments, the first embodiment and the second embodiment will be described in this order.

[0016] 〔Explanation of Common Matters〕 [Configuration of End Cap and Heating Cylinder: Refer to FIGS. 1, 2, and 3] The end cap 3, together with the heating cylinder 5, constitutes the injection device 1 and is fixed to one open end of the heating cylinder 5 by a plurality of fixing bolts B. Although the injection nozzle 7 is integrally formed with the end cap 3 in FIGS. 1 and 2, typically the injection nozzle 7 manufactured separately from the end cap 3 is fixed to the end cap 3 by means such as fastening. As an example, the fixing bolt B as a fastener is a bolt with a hexagonal hole tightened, but it is not limited to this and other forms of bolts can also be used, or a hub bolt type fastener can be adopted in which a bolt is provided on the side of the heating cylinder 5 and the end cap 3 is fixed with a nut. Inside the heating cylinder 5, the end cap 3, and the injection nozzle 7, a resin passage 4 is provided through which the molten resin plasticized by the rotational movement of the screw 9 provided inside the heating cylinder 5 passes toward the molding cavity of a mold (not shown). The heating cylinder 5 is provided with a heater (not shown) for plasticizing the raw material resin.

[0017] The end cap 3 is fixed to one end side of the heating cylinder 5 by fixing bolts B, which are fasteners, at a plurality of locations in the circumferential direction, four locations in FIG. 1 as an example. Bolt holes 3A through which the fixing bolts B penetrate are formed in the end cap 3, and female threads that mesh with the male threads of the fixing bolts B are formed in the heating cylinder 5. During injection molding, the fixing bolts B are tightened with a large torque so that the molten resin does not leak to the outside from the butting portion of the end cap 3 and the heating cylinder 5. Therefore, when removing the end cap 3 from the heating cylinder 5 during maintenance inspection of the injection device 1, for example, it is necessary to apply a large torque to the fixing bolts B to loosen them. This embodiment proposes a method for reducing the torque required to loosen the fixing bolts B.

[0018] [Reduction of torque for loosening fixing bolts B: Refer to FIGS. 2 and 3] When removing the end cap 3 from the heating cylinder 5, the temperature of the end cap 3 is lowered. By this temperature reduction, the torque T required to loosen the fixing bolts B can be reduced. This is the gist of this embodiment.

[0019] Assume that the end cap 3 is fixed to the heating cylinder 5 by the fastening force F (hereinafter referred to as the fastening force) by the fixing bolt B (Fig. 2). Let the dimension of the end cap 3 in the axial direction C be L. Also, let the amount of shrinkage (compression amount) of the end cap 3 due to the fastening force F and the spring constant, and the amount of elongation and the spring constant of the fixing bolt B due to the fastening force F be as follows. Shrinkage amount of the end cap 3: L1 Spring constant of the end cap 3: K1 Elongation amount of the fixing bolt B: L2 Spring constant of the fixing bolt B: K2

[0020] Since the compressive force of the end cap 3 and the fastening force F of the fixing bolt B are in balance, Equation (1) holds.

[0021] When the end cap 3 is cooled from this state, the end cap 3 shrinks by L11 due to thermal contraction in the axial direction C. Therefore, the remaining shrinkage amount L after cooling remaining in the end cap 3 C is as shown in Equation (2). As a result, the remaining fastening force F11 remaining in the fixing bolt B is as shown in Equation (3). Since the compressive force of the end cap 3 and the fastening force F of the fixing bolt B are in balance, the remaining fastening force F21 remaining in the fixing bolt B is as shown in Equation (4). In Equation (3), since L11 is a positive number, it becomes as shown in Equation (5).

[0022] An abutting load Cf is generated between the thread 3T of the end cap 3 and the thread BT of the fixing bolt B, and the resistance force for loosening the fixing bolt B is the frictional force Sf between the thread 3T and the thread BT. Since this frictional force Sf of the thread is caused by the fastening force F of the fixing bolt B, if the fastening force of the fixing bolt B can be reduced, the frictional force Sf of the thread can be reduced. The tightening force is the force (compressive force) that the bolt crushes (compresses) the fastened object by the thrust force of the screw (the force that advances into the nut). That is, the greater the elongation of the bolt and the compression of the fastened object, the greater the tightening force, and the smaller the elongation of the bolt and the compression of the fastened object, the smaller the tightening force. Therefore, by cooling the end cap 3, the end cap 3 contracts, so the remaining tightening force (F11, F21) can be reduced by cooling the end cap 3. As a result, the frictional force (surface pressure) Sf, which is the resistance to loosening the fixing bolt B, is reduced, and the torque T required to loosen the fixing bolt B can be reduced.

[0023] F = K1 * L1 = K2 * L2 …(1) L C = L1 - L11 …(2) F11 = K1 * (L1 - L11) …(3) F21 = F11 < F …(4) L1 - L11 < L1, F11 < F …(5)

[0024] Furthermore, as shown in the second embodiment described later, when the fixing bolt heater 38 is heated while being fitted into the fixing bolt B, if the amount of thermal expansion in the axial direction C of the fixing bolt B is L22, the remaining amount of shrinkage of the end cap 3 is further reduced and becomes as shown in Equation (6), and the remaining tightening force F12 of the fixing bolt B becomes as shown in Equation (7). Therefore, since F12 < F11, the tightening force of the fixing bolt B is further reduced. In this way, in addition to cooling the end cap 3, heating the fixing bolt B can further reduce the torque applied to the fixing bolt B, making it easier to loosen the fixing bolt B.

[0025] L1 - (L11 + L22) …(6) F12 = K1 * (L1 - (L11 + L22))…(7)

[0026] 〔First Embodiment: Refer to FIGS. 4 and 5〕 The injection device 1 according to the first embodiment will be described with reference to FIGS. 4 and 5. In addition to the elements described as common matters, the injection device 1 includes an assistance system 10A that functions when removing the fixing bolt B. The assistance system 10A includes a temperature detection unit 20 that detects the temperatures of the end cap 3 and the fixing bolt B, a cooling unit 30 that has a circulation path for supplying a cooling medium CM to the end cap 3, and a control unit 40 that controls the operation of the cooling unit 30 based on the detected temperatures acquired from the temperature detection unit 20.

[0027] [Temperature detection unit 20: Refer to FIG. 4] The temperature detection unit 20 includes a first temperature sensor 21 attached to the end cap 3 to detect the temperature of the end cap 3 (first detected temperature T1), and a second temperature sensor 23 attached to at least one fixing bolt B to detect the temperature of the fixing bolt B (second detected temperature T2). The temperature detection is continuously performed before removing the fixing bolt B from the end cap 3 and the heating cylinder 5. The first detected temperature T1 detected by the first temperature sensor 21 and the second detected temperature T2 detected by the second temperature sensor 23 are sent to a temperature management unit 41 related to the temperature management of the control unit 40.

[0028] The first temperature sensor 21 may be provided at only one location of the end cap 3, or may be provided at a plurality of locations of the end cap 3. Also, the second temperature sensor 23 may be provided at only one of the plurality of fixing bolts B, or may be provided at each of the plurality of fixing bolts B.

[0029] [Cooling unit 30: Refer to FIG. 4] The cooling unit 30 includes a cooling unit 31 that cools the end cap 3 with the supplied cooling medium CM, a storage tank 33 that stores the cooling medium CM supplied to the cooling unit 31, a circulation path 35 of the cooling medium CM that connects the cooling unit 31 and the storage tank 33, and a circulation pump 37 that circulates the cooling medium CM in the circulation path 35.

[0030] The cooling unit 31 includes a housing 31A fixed to the end cap 3, and a heat transfer tube 31B that penetrates the housing 31A and through which a cooling medium CM flows inside. The cooling unit 31 cools the end cap 3 by heat exchange between the cooling medium CM flowing through the heat transfer tube 31B and the end cap 3 via the housing 31A. The housing 31A and the heat transfer tube 31B are made of a metal material with excellent thermal conductivity such as copper, copper alloy, aluminum, or aluminum alloy. In particular, it is preferable that the cooling unit 31 is made of these metal materials and is manufactured by casting the heat transfer tube 31B into the housing 31A, as it facilitates the handling and installation of the cooling unit 31 by the operator. The form in which the cooling unit 31 is provided on the end cap 3 is arbitrary. For example, the cooling unit 31 may be integrally formed in an annular shape continuously on the outer peripheral surface of the end cap 3, or a plurality of cooling units 31 may be provided at intervals on the outer peripheral surface of the end cap 3.

[0031] The circulation path 35 includes a forward path 35A through which the cooling medium CM stored in the storage tank 33 flows toward the cooling unit 31, and a return path 35B through which the cooling medium CM that has passed through the heat transfer tube 31B of the cooling unit 31 and has undergone heat exchange flows toward the storage tank 33. The circulation pump 37 is provided in the forward path 35A of the circulation path 35. It pumps up the cooling medium CM from the storage tank 33 and pumps the cooling medium CM toward the heat transfer tube 31B of the cooling unit 31. The pumped cooling medium CM returns to the storage tank 33 through the return path 35B after passing through the cooling unit 31. At this time, the cooling medium CM returned to the storage tank 33 through the return path 35B is cooled by a heat exchanger such as a cooling tower (not shown). By operating the circulation pump 37 in this way, the cooling medium CM circulates through the circulation path 35. The operation of the circulation pump 37 is controlled by the pump management unit 43 of the control unit 40. The cooling unit 31 and the storage tank 33 form a part of the circulation path 35 of the cooling medium CM.

[0032] [Control unit 40: Refer to FIG. 4] The control unit 40 includes a temperature management unit 41 that acquires the first detected temperature T1 from the first temperature sensor 21 and the second detected temperature T2 from the second temperature sensor 23, and a pump management unit 43 that controls the operation of the circulation pump 37 based on the temperature management information acquired from the temperature management unit 41. The control unit 40 is composed of a computer device and includes input means such as a keyboard and a touch panel, and display means for displaying character information, graphic information, and the like.

[0033] [Temperature management unit 41] The temperature management unit 41 is responsible for a first management for determining the start of cooling of the end cap 3 and a second management for determining the start of removal of the end cap 3. The temperature management unit 41 proceeds with the first management first and then shifts to the second management. In addition to holding the cooling start temperature Ts for the first management, the temperature management unit 41 holds the work start temperature Te for the second management. The cooling start temperature Ts and the work start temperature Te are preset and recorded in the temperature management unit 41.

[0034] As the first management, the temperature management unit 41 compares the acquired first detected temperature T1 with the cooling start temperature Ts. If the first detected temperature T1 has reached the cooling start temperature Ts, it notifies the pump management unit 43 that the condition for starting cooling is satisfied as an operation start command C1. Further, as the second management, the temperature management unit 41 compares the acquired first detected temperature T1 with the work start temperature Te. If the first detected temperature T2 has reached the work start temperature Te, it issues a notification prompting the start of the removal work of the end cap 3. Also, if the first detected temperature T2 has reached the work start temperature Te, the temperature management unit 41 can notify the pump management unit 43 that the condition for starting work is satisfied as an operation stop command C2 for the circulation pump 37. Here, the first detected temperature T1 is used, but the first detected temperature T1 can be replaced with the second detected temperature T2, or both the first detected temperature T1 and the second detected temperature T2 can be used. The procedure described later adopts an example of using both.

[0035] When the pump management unit 43 acquires the operation start command C1 from the temperature management unit 41, it controls the circulation pump 37 so that the circulation pump 37 operates. When the circulation pump 37 starts operating, the cooling medium CM flows through the circulation path 35, and the cooling of the end cap 3 is started. When the pump management unit 43 acquires the operation stop command C2 from the temperature management unit 41, it controls the circulation pump 37 so that the circulation pump 37 stops operating. When the circulation pump 37 stops operating, the cooling of the end cap 3 is stopped.

[0036] [Control procedure of support system 10A: Refer to FIGS. 5 and 9] The control procedure when removing the end cap 3 by the support system 10A will be described. This control procedure is executed by the control unit 40 acquiring the first detection temperature T1 and the second detection temperature T2 from the temperature detection unit 20 and sending an operation command to the cooling unit 30 based on the acquired information. Note that the following control procedure is shown as graph A in FIG. 9 which is a diagram, so please refer to it together.

[0037] <Temperature confirmation of end cap 3 / heating cylinder 5: FIGS. 5 S101, S102> The control unit 40 determines whether at least one of the first detection temperature T1 by the first temperature sensor 21 and the second detection temperature T2 by the second temperature sensor 23 has reached the cooling start temperature Ts. That is, the control unit 40 determines T1 ≥ Ts or T2 ≥ Ts. This determination is made to ensure the removal of the end cap 3 from the heating cylinder 5 as described below.

[0038] After the forming operation is completed, the end cap 3 is removed. However, resin inevitably remains inside the heating cylinder 5 after the forming operation is completed. If the residual resin existing across the end cap 3 and the heating cylinder 5 is solidified, the end cap 3 can be regarded as being joined to the heating cylinder 5 by a resin adhesive. Then, even if the fixing bolt B is removed, it is not easy to remove the end cap 3 from the heating cylinder 5. Therefore, in order to confirm that the residual resin is in a molten state and not solidified, a determination is made as to whether at least one of the first detection temperature T1 and the second detection temperature T2 has reached the cooling start temperature Ts.

[0039] Since the cooling start temperature Ts serves as a criterion for determining whether the residual resin is in a molten state, it can be set according to the material of the resin material used for injection molding. However, the cooling start temperature Ts can also be set to a constant value based on the resin material with the highest melting point or flow start point among the resin materials used for injection molding.

[0040] If at least one of the first detection temperature T1 and the second detection temperature T2 has reached the cooling start temperature Ts, the process proceeds to the next procedure related to the cooling of the end cap 3 (S101 Y). If at least one of the first detection temperature T1 and the second detection temperature T2 has not reached the cooling start temperature Ts, while heating the heating cylinder 5, this determination is continued (S101 N, S102). For heating the heating cylinder 5, the heater provided in the heating cylinder 5 can be used to melt the raw material resin for injection molding.

[0041] If the end cap 3 is removed before the passage of time since the end of the forming operation, the residual resin is still in a molten state. However, if a considerable amount of time has passed since the end of the forming operation due to circumstances, the residual resin may have solidified. In this case, it is determined that at least one of the first detection temperature T1 and the second detection temperature T2 has not reached the cooling start temperature Ts, but the heating cylinder 5 can also be heated prior to this determination. That is, in the present embodiment, the determination can also be made after heating the heating cylinder 5 in advance until it reaches the cooling start temperature Ts.

[0042] Here, both the first detection temperature T1 and the second temperature information T2 are acquired for determination, but determination may be made by acquiring only one of the first detection temperature T1 and the second temperature information T2. That is, it is only necessary to ensure that the solidification of the residual resin does not prevent the end cap 3 from being removed from the heating cylinder 5.

[0043] [Cooling of End Cap 3: Fig. 5 S103, S105] If at least one of the first detection temperature T1 and the second detection temperature T2 has reached the cooling start temperature Ts, the control unit 40 performs control for cooling the end cap 3 as follows. The following control and determination are to determine whether the end cap 3 is cooled to such an extent that the fixed bolt B can be removed without force.

[0044] When the first detection temperature T1 reaches the cooling start temperature Ts, the temperature management unit 41 of the control unit 40 notifies the pump management unit 43 of this fact as the operation start command C1. When the pump management unit 43 acquires the operation start command C1, it instructs the circulation pump 37 to start operation. When the operation of the circulation pump 37 is started, the cooling medium CM flows through the circulation path 35, and the cooling unit 31 cools the end cap 3 (S103).

[0045] When the cooling medium CM starts to circulate through the circulation path 35, the temperature management unit 41 of the control unit 40 acquires the first detection temperature T1 by the first temperature sensor 21 and compares it with the work start temperature Te (S105). If the first detected temperature T1 has dropped to the operation start temperature Te (S103 Y, T1 ≤ Te), the temperature management unit 41 issues a notification as an indication that the precondition for the operation of loosening the fixing bolt B and removing the end cap 3 is satisfied (S107). For example, the control unit 40 can visually notify character information such as "Please start the operation of loosening the fixing bolt B and removing the end cap 3" on a display provided in the control unit 40. Instead of or in addition to this visual information, the same text can be notified as voice. Furthermore, it is also possible to notify that the operation of removing the fixing bolt B is about to start by emitting light.

[0046] If the first detected temperature T1 has dropped to the operation start temperature Te, in addition to the above, the temperature management unit 41 can also notify the pump management unit 43 to that effect. When the pump management unit 43 acquires the information to that effect, it instructs the circulation pump 37 to stop. However, it is not necessary to immediately stop the circulation pump 37, and the operation may be stopped after continuing the operation of the circulation pump 37. This is because even if the first detected temperature T1 has dropped significantly below the operation start temperature Te by continuing the cooling, it does not interfere with the removal of the fixing bolt B.

[0047] [Criteria for setting the operation start temperature Te] The operation start temperature Te is not limited to a specific temperature as long as the torque applied when loosening the fixing bolt B can be reduced by contracting the end cap 3 in the axial direction C. However, there is a preferable temperature in relation to the residual resin. It is preferable to remove the fixing bolt B when the temperature of the end cap 3 (the first detected temperature T1) is higher than the heat distortion temperature Tf of the residual resin in the heating cylinder 5. The heat distortion temperature is also referred to as the temperature of deflection under load and is specified for various resins. The preferable operation start temperature Te is set in the range of the melting point ±20°C for crystalline resins and in the range of the flow start point ±20°C for amorphous resins.

[0048] The reasons for setting the operation start temperature Te within the preferred range as described above are as follows. Reason 1: To remove the end cap 3 from the heating cylinder 5, it is necessary to peel the end cap 3 from the residual resin in the heating cylinder 5. However, when the temperature of the residual resin is in a solidified state lower than the heat distortion temperature, the residual resin adheres firmly to the end cap and it is not easy to peel it off. Reason 2: When the cooling medium CM is at a temperature around room temperature, if the operation start temperature Te is lower than the heat distortion temperature of the residual resin, the temperature difference from the cooling medium CM becomes small. Then, the temperature drop rate of the end cap 3 decreases, the cooling time becomes longer, and the working efficiency becomes low.

[0049] Reason 3: If the end cap 3 is cooled down to a temperature below the heat distortion temperature, even if the fixing bolt B is removed, due to Reason 1 above, in order to remove the end cap 3, it is necessary to reheat the end cap temperature to a temperature above the heat distortion temperature, resulting in poor working efficiency. Reason 4: The molten resin adhering to the metal is likely to peel off from the metal around the temperature at which it solidifies or deforms. Specifically, as the resin that has advanced in melting penetrates into the minute irregularities on the metal surface, the adhesion between the metal and the molten resin becomes stronger and it becomes difficult to peel off. However, as the temperature decreases from the molten state to near the melting point for crystalline resins and near the glass transition point for amorphous resins, due to shrinkage and increase in viscosity of the resin material, the resin material that had penetrated into the minute recesses on the metal surface rises, creating a gap between the metal surface. As a result, around the melting point for crystalline resins and around the flow start point for amorphous resins, it becomes easier to peel off from the surface of the end cap.

[0050] [Effects according to the first embodiment] According to the support system 10A, by cooling and thermally shrinking the end cap 3 tightened by the fixing bolt B, the amount of shrinkage of the end cap 3 can be reduced. As a result, the amount of elongation of the fixing bolt B due to the fastening force (screw thrust) generated in the fixing bolt B when the end cap 3 is attached is also reduced. Then, since the surface pressure (frictional force Sf) generated on the thread is reduced, the torque required to loosen the fixing bolt B can be reduced.

[0051] According to the support system 10A, before cooling the end cap 3, it is confirmed that the residual resin is in a molten state. Therefore, according to the support system 10A, after removing the fixing bolt B, the removal of the end cap 3 can be ensured.

[0052] 〔Second Embodiment: Refer to FIGS. 6, 7, 10, and 11〕 The support system 10B according to the second embodiment will be described with reference to FIGS. 6 and 7. In addition, since the diagram corresponding to FIG. 9 of the first embodiment is shown in graph B of FIG. 10, please refer to it together. As shown in FIG. 6, the support system 10B, in addition to the configuration of the support system 10A, has a rod-shaped fixing bolt heater 38 inserted into the fixing bolt B. The fixing bolt heater 38 generates heat in parallel with the cooling of the end cap 3 by the cooling medium CM, and heats and raises the temperature of the fixing bolt B (FIG. 7 S106).

[0053] When the temperature of the fixing bolt B is increased by the heating heater 38, the fixing bolt B thermally expands in its axial direction C. Therefore, the amount of elongation due to the fastening force of the fixing bolt B also decreases compared to before heating. Specifically, for example, assume that the length of the fixing bolt B in the unloaded state at room temperature is 100 cm, and the elongation due to the fastening force is 5 mm. In this case, the fastening force F, which is the tensile force applied to the fixing bolt B, is F = K2 * 5 mm according to Equation (1). At this time, assume that the temperature of the fixing bolt B is increased and the thermal expansion amount in the axial direction C becomes 3 mm. Then, the length of the fixing bolt B in the unloaded state is 103 mm (= 100 mm at room temperature + 3 mm of thermal expansion). On the other hand, before the temperature increase, the fixing bolt B was stretched to 105 mm (= 100 mm at room temperature + 5 mm of elongation due to the fastening force) by fastening. Therefore, the amount of elongation of the fixing bolt B due to the fastening force after the temperature increase is 2 mm (= 105 mm - 103 mm). The fastening force F generated in the fixing bolt B at this time is F = K2 * 2 mm according to Equation (1), which is a tensile force smaller than the fastening force F (K1 * 5 mm) generated during fastening at room temperature. As a result, the tensile force generated in the fixing bolt B also decreases, so the surface pressure generated on the thread further decreases, and the torque required to loosen the fixing bolt B can be further reduced.

[0054] In addition to the above, as long as the gist of the present invention is not deviated from, it is possible to select the configurations listed in the above embodiments or to appropriately change them to other configurations. In the above embodiment, the end cap 3 was cooled using the cooling medium CM. However, the present invention can also cool the end cap 3 without using the cooling medium CM. For example, when air conditioning is performed by an air conditioner or the like, or when the ambient temperature is low due to low temperatures in winter, etc., it is possible to cool the end cap 3 without using the cooling medium CM. In this case, the end cap 3 can also be cooled by heat radiation.

[0055] As shown in FIG. 8, an end cap heating heater 39 can be incorporated in the cooling unit 31. The end cap heating heater 39 is used to heat the end cap 3 when the end cap 3 has not reached the cooling start temperature Ts.

[0056] As described above, both the first embodiment and the second embodiment reduce the torque required when loosening the fixing bolt B by providing a difference in thermal expansion amount between the end cap 3 and the fixing bolt B. Then, in order to provide the difference in thermal expansion amount, both the first embodiment and the second embodiment reduce the dimension of the end cap 3 in the axial direction C by cooling the end cap 3, and in addition, the second embodiment increases the dimension of the fixing bolt B in the axial direction C. The present invention can also adopt only increasing the dimension of the fixing bolt B in the axial direction C as shown in the graph C of FIG. 10.

[0057] In the graph C of FIG. 10, when removing the end cap 3 after injection molding, the detected temperature T1 of the end cap 3 decreases due to natural cooling, while the fixing bolt heater 38 provided on the fixing bolt B generates heat. Then, the control unit 40 calculates the difference (T2 - T1) between the detected temperature T1 and the detected temperature T2, compares this difference with the working start temperature difference ΔT, and if the difference (T2 - T1) satisfies the condition regarding the working start temperature, that is, the condition (T2 - T1) ≧ ΔT, the control unit 40 can issue a suggestion to loosen the fixing bolt B. Further, since the temperature of the end cap 3 is decreasing, the fixing bolt B in contact with the end cap 3 is also deprived of a certain amount of heat by the end cap 3. Therefore, when the size and capacity of the bolt heater 38 cannot be increased, as shown in the graph D of FIG. 11, the temperature of the fixing bolt B may drop even when heated by the bolt heater 38. Even in this case, the control unit 40 calculates the difference (T2 - T1) between the detected temperature T1 and the detected temperature T2, compares this difference with the working start temperature difference ΔT, and if the difference (T2 - T1) satisfies the condition regarding the working start temperature, that is, the condition (T2 - T1) ≧ ΔT, the control unit 40 can issue a suggestion to loosen the fixing bolt B.

[0058] In the case of the second embodiment, as conditions regarding the working start temperature, as shown in FIG. 10, it is possible to adopt one or both of the conditions that the difference (T2 - T1) regarding the working start temperature satisfies (T2 - T1) ≧ ΔT, and that, as in S105 shown in FIG. 7, the first detected temperature T1 satisfies the condition of the cooling start temperature Te.

Explanation of Signs

[0059] 1 Injection device 3 End cap 4 Resin passage 5 Heating cylinder 7 Injection nozzle 9 Screw 10A Support system 10B Support system 20 Temperature detection unit 21 First temperature sensor 23 Second temperature sensor 30 Cooling unit 31 Cooling unit 31A Housing 31B Heat transfer pipe 33 Storage tank 35 Circulation path 35A Forward path 35B Return path 37 Circulation pump 38 Fixed bolt heating heater 39 End cap heating heater 40 Control unit 41 Temperature management unit 43 Pump management unit

Claims

1. An assistance system that functions when removing an end cap fixed with a fastener from a heating cylinder of an injection device, a temperature detection unit that detects the temperature of one or both of the end cap and the fastener, and a control unit that suggests removal of the fastener if the detected temperature detected by the temperature detection unit satisfies a condition of a predetermined operation start temperature. Assistance system.

2. A cooling unit provided with a cooling unit provided on the end cap and a supply source that supplies a cooling medium to the cooling unit, The control unit, controls the supply of the cooling medium to the cooling unit based on the detected temperature detected by the temperature detection unit, The assistance system according to claim 1.

3. The control unit, if the detected temperature satisfies a condition of a predetermined cooling start temperature, operates the supply source so that the cooling medium is supplied to the cooling unit, and executes cooling of the end cap by the cooling unit, The assistance system according to claim 2.

4. A fastener heater that is fitted into the fastener, The control unit, during the execution of cooling of the end cap, instructs heating of the fastener heater, The assistance system according to claim 2.

5. The control unit, sets the operation start temperature higher than the heat distortion temperature of the residual resin left in the heating cylinder, and compares it with the detected temperature, The assistance system according to claim 2.

6. The control unit, sets the operation start temperature in a temperature range of ±20°C with respect to the melting point or flow start point of a partial component or main component of the residual resin, The assistance system according to claim 5.

7. The control unit, if the temperature difference between the detected temperature T1 of the end cap and the detected temperature T2 of the fastener by the temperature detection unit satisfies a condition of a predetermined operation start temperature difference, suggests removal of the fastener, The assistance system according to claim 1.

8. A fastener heater that is fitted into the fastener, The control unit, after instructing heating of the fastener heater, if the temperature difference (T2 - T1) between the detected temperature T1 and the detected temperature T2 satisfies a condition of a predetermined operation start temperature difference, suggests removal of the fastener, The assistance system according to claim 7.

9. A method for removing an end cap fixed with a fastener from a heating cylinder of an injection device, A first step of detecting the temperature of one or both of the end cap and the heating cylinder; A second step of performing an operation of loosening the fastener if the detected temperature detected in the first step satisfies a condition of a predetermined operation start temperature; A method for removing an end cap including the above.

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