Thermocouple mounting structure, machine equipment with the same, and method of installing thermocouple mounting structure

Abstract

To provide a thermocouple mounting structure that allows for more reliable removal of a thermocouple retainer from the cylinder.SOLUTION: The thermocouple mounting structure 5 is attached to a cylinder 32 for heating and melting material. The thermocouple mounting structure 5 comprises an intermediate mounting member 52 having an external thread groove 52A on its outer surface that engages with a screw hole 38 provided in the cylinder 32, and an internal thread groove 52B on its inner surface, and a thermocouple retainer 51 that is screwed into the internal thread groove 52B of the intermediate mounting member 52 and holds a thermocouple 4. The intermediate mounting member 52 is made of a different material from the thermocouple retainer 51.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a thermocouple mounting structure, a mechanical device including the same, and a method for installing the thermocouple mounting structure. [Background technology]

[0002] An injection molding machine is equipped with a cylinder for heating and melting the material to be injected. A thermocouple is attached to the cylinder to monitor the temperature of the cylinder. Patent Document 1 describes a thermocouple attachment structure. A screw hole is provided in the cylinder, and a hollow thermocouple holder is screwed into the screw hole. The thermocouple is inserted into the hollow part of the thermocouple holder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-333372 A Summary of the Invention [Problem to be solved by the invention]

[0004] The thermocouple holder may be removed from the cylinder for inspection, etc. The thermocouple holder is screwed to the cylinder, so it can usually be easily removed from the cylinder. However, if the cylinder is exposed to high temperatures for an extended period of time, the male threads of the thermocouple holder may seize, making it impossible to remove the thermocouple holder. In that case, a process such as forcibly removing the thermocouple holder by machining may be required.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a thermocouple mounting structure that enables a thermocouple holder to be more reliably removed from a cylinder. [Means for solving the problem]

[0006] The thermocouple mounting structure includes an intermediate mounting member having an outer thread groove on its outer surface that meshes with a threaded hole provided in the cylinder and an inner thread groove on its inner surface, and a thermocouple holder that is screwed into the inner thread groove of the intermediate mounting member and holds the thermocouple. The intermediate mounting member is made of a different material from the thermocouple holder. Effect of the Invention

[0007] According to the present invention, it is possible to provide a thermocouple mounting structure that enables a thermocouple holder to be more reliably removed from a cylinder. [Brief description of the drawings]

[0008] [Figure 1] 1 is a front view of an injection molding machine according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an enlarged view of part A in FIG. 1 showing a thermocouple and its mounting structure. [Diagram 3] FIG. 4 is a cross-sectional view of the intermediate mounting member. [Figure 4] FIG. [Diagram 5] 13A and 13B are diagrams showing modified examples of the mounting structure of a thermocouple. [Figure 6] 13 is a diagram showing a thermocouple mounting structure according to Modification 1. FIG. [Figure 7] FIG. 11 is a cross-sectional view of an intermediate mounting member of Modified Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Overall configuration of injection molding machine> FIG. 1 shows a schematic front view of an injection molding machine 1 according to a first embodiment. The injection molding machine 1 is a horizontal metal injection molding machine that injects molten metal such as magnesium or aluminum. The injection molding machine 1 is generally composed of a clamping device 2 that clamps a mold, and an injection device 3 that heats, melts, and injects the metal material to be injected. The metal material that is heated, melted, and injected is sometimes called molten metal. In the following explanation, the X direction refers to the axial direction of the cylinder 32. Terms such as "front" and "rear" are defined based on the injection direction.

[0010] <Mold clamping device 2> The mold clamping device 2 includes a fixed platen 21 fixed on a bed (not shown) to which a fixed mold M1 is attached, and a movable platen 22 slidable on the bed to which a movable mold M2 is attached. A mold clamping housing (not shown) slidable on the bed is provided on the opposite side of the fixed platen 21 with respect to the movable platen 22, and the fixed platen 21 and the mold clamping housing are connected by a plurality of tie bars 23. A link mechanism (not shown) for opening and closing the mold is provided between the movable platen 22 and the mold clamping housing. The link mechanism is driven by an electric ball screw. Instead of the link mechanism, a hydraulic mold clamping cylinder may be provided. A cavity M3 is formed between the fixed mold M1 and the movable mold M2 and is filled with molten metal.

[0011] <Injection device 3> The injection device 3 is provided on a base (not shown). The injection device 3 includes a hollow cylinder 32 for heating and melting the metal material to be injected, a screw 33 housed in the cylinder 32, and a drive mechanism 34 for driving the screw 33. The screw 33 is driven to rotate by the drive mechanism 34 and is driven in the X direction (moves back and forth). A heater 39 for heating and melting the metal material is wound around the outer periphery of the cylinder 32. As shown in FIG. 2, the heater 39 is covered with a heat insulating material 40.

[0012] The cylinder 32 is roughly divided into a supply section P1, a compression section P2, and a metering section P3 from the rear to the front. A hopper 36 is provided in the supply section P1, and the metal material in pellet form is supplied thereto. The metal material is sent to the compression section P2 while receiving residual heat from a heater 39. The metal material is compressed, heated, and kneaded in the compression section P2 to become molten, and is then transported to the metering section P3. The metering section P3 measures the molten metal to be injected in one injection cycle (shot). The screw 33 is provided with a screw head 35 at its tip in the X direction. An injection nozzle 37 is attached to the tip of the cylinder 32 to supply molten metal to the cavity M3.

[0013] <Thermocouple 4 and its mounting structure 5> FIG. 2 is an enlarged view of part A in FIG. 1 showing the thermocouple 4 and its mounting structure 5, and FIG. 3 is an exploded view of the thermocouple 4 and its mounting structure 5. A plurality of thermocouples 4 for measuring and controlling the cylinder temperature are attached to the cylinder 32. As shown in FIG. 1, a thermocouple 4 is provided for each heater control zone (not shown) of the cylinder 32. One thermocouple 4 may control one heater 39, or multiple heaters 39 (e.g., two or three). In addition to the control thermocouple 4, a spare thermocouple may be attached to detect abnormal heating, etc. The thermocouple 4 is attached to the cylinder 32 by a thermocouple mounting structure 5.

[0014] The thermocouple mounting structure 5 has a thermocouple holder 51 that holds the thermocouple 4, a threaded hole 38 (see FIG. 3) of the thermocouple holder 51 provided in the cylinder 32, and an intermediate mounting member 58. The threaded hole 38 has a threaded hole portion 38A that extends from the outer surface of the cylinder 32 to the inside of the cylinder 32, and a small diameter portion 38B that is coaxial with the threaded hole portion 38A and has a smaller diameter than the threaded hole portion 38A. A female thread 38C is provided on the inner surface of the threaded hole portion 38A.

[0015] 2 and 3, the thermocouple holder 51 is a hollow cylindrical member having a male screw 51A at its tip. The thermocouple holder 51 is attached to the cylinder 32 via an intermediate mounting member 52. The thermocouple holder 51 extends outward from the cylinder 32 through through holes 39A and 40A provided in the heater 39 and the thermal insulation material 40, respectively. The thermocouple 4 is inserted into the hollow portion of the thermocouple holder 51 and further into the small diameter portion 38B of the screw hole 38, with one end contacting the bottom portion 38D of the screw hole 38. The thermocouple 4 extends outward from the thermocouple holder 51, and a lead wire 41 extends from the other end on the outer side.

[0016] A cap member 58 is provided at the tip of the thermocouple holder 51, and the cap member 58 is fixed to the thermocouple holder 51 by a screw (not shown) provided on the inner surface. The cap member 58 is a cylindrical member, and one end is provided with a bottom 58B having an opening 58A through which the thermocouple 4 passes, and the other end is an open end 53C.

[0017] A coil spring 53 is wound around the thermocouple 4. One end 53A of the coil spring 53 has a larger diameter than other portions. The coil spring 53 is inserted into an opening 58A from the open end 53C side of a cap member 58, and the expanded end 53A is held on the inner surface of a bottom portion 58B of the cap member 58. A cylindrical spring adjustment fitting 54 is provided around the thermocouple 4, and the coil spring 53 is inserted between the thermocouple 4 and the spring adjustment fitting 54. The other end 53B of the spring is fixed to the thermocouple 4 with a screw 55 via the spring adjustment fitting 54.

[0018] Applying a tensile force to the coil spring 53 causes one end 53A of the coil spring 53 to come into close contact with the inner surface of the bottom 58B of the cap member 58. This tensile force causes the coil spring 53 to apply a downward force (elastic restoring force) to the thermocouple 4 at the portion where the thermocouple 4 is fixed to the spring adjustment fitting 54. This allows the tip of the thermocouple 4 to stably contact the bottom 38D of the screw hole 38, making it possible to measure the cylinder temperature with high accuracy. The elastic restoring force of the coil spring 53 can be adjusted by the position of the spring adjustment fitting 54.

[0019] <Intermediate mounting member 52> In general, if a structure having a screw hole and a screw that engages with the screw hole are kept at high temperature for a long period of time, the screw is likely to seize. In particular, if the structure having a screw hole and the screw are made of the same material and a large load is applied to the contact surface between the screw and the structure, adhesion and seizing are likely to occur. In the case of the metal injection molding machine 1 of this embodiment, the cylinder temperature reaches 600 to 700°C. The thermocouple 4 and the thermocouple holder 51 may be removed from the cylinder 32 for the purpose of maintenance of the cylinder 32, etc. If the male thread 51A of the thermocouple holder 51 seizes and the thermocouple holder 51 cannot be removed, not only will maintenance be hindered, but it may also be necessary to install a new thermocouple 4 in another location on the cylinder 32.

[0020] Therefore, in the thermocouple mounting structure 5 of the present embodiment, an intermediate mounting member 52 made of a different material from that of the thermocouple holder 51 is interposed between the screw hole 38 provided in the cylinder 32 and the thermocouple holder 51. "Different material" means that the element with the highest component ratio in the intermediate mounting member 52 is different from the element with the highest component ratio in the thermocouple holder 51.

[0021] Fig. 4 is an enlarged view of part B in Fig. 2, showing the intermediate mounting member 52, the thermocouple holder 51, and the cylinder 32, and Fig. 5 is a perspective view of the intermediate mounting member 52. The intermediate mounting member 52 is made by winding a wire rod with a diamond-shaped cross section into a coil shape. Adjacent turns are in close contact or have a small gap between them, and the intermediate mounting member 52 is formed into a generally hollow cylindrical or coil shape as a whole.

[0022] The outer surface of the intermediate mounting member 52 has an outer thread groove 52A that meshes with the threaded hole portion 38A of the threaded hole 38 of the cylinder 32, and the inner surface of the intermediate mounting member 52 has an inner thread groove 52B that meshes with the male thread 51A of the thermocouple holder 51. The intermediate mounting member 52 is screwed into the threaded hole 38 of the cylinder 32 using a dedicated tool, and then the thermocouple holder 51 is screwed into the inner thread groove 52B of the intermediate mounting member 52.

[0023] The intermediate mounting member 52 and the thermocouple holder 51 are made of metal, but are made of different materials. In this embodiment, the thermocouple holder 51 is made of a general steel material, and the intermediate mounting member 52 is made of a nickel alloy. That is, the metal element with the highest component ratio in the intermediate mounting member 52 is nickel, and the metal element with the highest component ratio in the thermocouple holder 51 is iron. The nickel alloy is preferable because it has excellent high-temperature durability.

[0024] <Effects of this embodiment> The effects of this embodiment will be described. The seizure of the male thread 51A of the thermocouple holder 51 can be suppressed, for example, by making the thermocouple holder 51 from a nickel alloy. However, nickel alloys are expensive. In this embodiment, it is only necessary to attach the intermediate mounting member 52, and the intermediate mounting member 52 may be a commercially available product, so additional costs can be suppressed. An example of a commercially available product is Recoil (registered trademark) "Inconel X-750" from Ikeda Metal Mining Co., Ltd. Although commercially available products are used as members for reinforcing or repairing female threads, in this embodiment, they are used to suppress seizure of the threads.

[0025] Since the cylinder 32 is made of steel, the intermediate mounting member 52 and the cylinder 32 are also made of different materials. Therefore, seizure is unlikely to occur between the outer screw groove 52A of the intermediate mounting member 52 and the screw hole 38 of the cylinder 32. In the unlikely event that seizure occurs between the inner screw groove 52B of the intermediate mounting member 52 and the male screw 51A of the thermocouple holder 51 and the thermocouple holder 51 becomes unable to rotate relative to the cylinder 32, there is a possibility that the intermediate removal member may be able to rotate relative to the screw hole 38 of the cylinder 32.

[0026] Therefore, even if the thermocouple holder 51 cannot be removed alone from the intermediate mounting member 52, it may be possible to remove the thermocouple holder 51 together with the intermediate mounting member 52. In this manner, in this embodiment, the means for removing the thermocouple holder 51 from the cylinder 32 is made redundant, thereby improving reliability.

[0027] <Variation 1> Fig. 6 is a view similar to Fig. 2 but showing a first modified example of this embodiment. In this modified example, the method of fixing the thermocouple 4 to the thermocouple holder 51 is different. The coil spring 53 is provided on the cylinder 32 side of the cap member 58. The thermocouple 4 is provided with a receiving portion 42 for the coil spring 53, and one end of the coil spring 53 is held by the receiving portion 42 and the other end is held by a bottom portion 58B of the cap member 58. The cap member 58 has a claw portion 56 that protrudes radially inward, and the thermocouple holder 51 has a hook 57 that protrudes radially outward.

[0028] When a coil spring 53 is attached between the cap member 58 and the receiving portion 42 and the cap member 58 is pressed into the cylinder 32, the coil spring 53 is compressed and the thermocouple 4 is pressed into the screw hole 38. When the cap member 58 is rotated, the claw portion 56 is caught by the hook 57 (bayonet lock system). In this modified example, an intermediate mounting member 52 similar to that of the above embodiment is provided, and the thermocouple holder 51 is fixed to the intermediate mounting member 52 in the same manner.

[0029] <Variation 2> 7 is a cross-sectional view of an intermediate mounting member 152 according to Modification 2 of this embodiment. The intermediate mounting member 152 is a hollow cylindrical member, and has an outer screw groove 152A on its outer surface that meshes with the screw hole portion 38A of the screw hole 38 of the cylinder 32, and an inner screw groove 152B on its inner surface that meshes with the male screw 51A of the thermocouple holder 51. Unlike the above embodiment, the intermediate mounting member 152 is not wound with wire, but is a hollow cylindrical member with threads machined on both sides. The intermediate mounting member 152 is formed of, for example, a nickel alloy. Such an intermediate mounting member 152 also has the same effects as the intermediate mounting member 52.

[0030] Although this embodiment relates to a thermocouple mounting structure for a metal injection molding machine, the present invention is not limited thereto. For example, the present invention is also applicable to a resin injection molding machine. The present invention is also applicable to a resin or metal extruder. The present invention is applicable to a machine having a cylinder for heating and melting a material, a thermocouple mounting structure attached to the cylinder, and a thermocouple attached to the mounting structure.

[0031] The present invention can also be applied to the modification of the above-mentioned mechanical device. When the thermocouple holder 51 is directly screwed into the screw hole 38 of the cylinder 32, the thermocouple mounting structure 5 of the present invention can be applied in the following procedure to reduce the possibility of the thermocouple holder 51 becoming seized.

[0032] First, the thermocouple 4 and the thermocouple holder 51 are removed from the cylinder 32. Next, the above-mentioned intermediate mounting member 52 (or 152) is attached to the threaded hole 38 of the cylinder 32. Next, the intermediate mounting member 51 is attached to the cylinder 32 by engaging the outer screw groove 52A with the threaded hole 38 provided in the cylinder 32. Next, the thermocouple holder 51, the coil spring 53, the cap member 58, and the thermocouple 4 are attached. At this time, since the threaded hole 38 of the cylinder 32 is effectively reduced in size by the amount of the intermediate mounting member 52 provided, it may be desirable to use thermocouple holder 51 and thermocouple 4 with smaller diameters than those originally provided.

[0033] (Additional Note) This specification includes the following disclosure. [Configuration 1] A mounting structure for a thermocouple attached to a cylinder for heating and melting a material, comprising: an intermediate mounting member having an outer surface with an outer screw groove that engages with a screw hole provided in the cylinder and an inner surface with an inner screw groove; a thermocouple holder that is screwed into the inner screw groove of the intermediate mounting member and holds a thermocouple; having The intermediate mounting member is made of a material different from that of the thermocouple holder. [Configuration 2] 2. The thermocouple mounting structure according to claim 1, wherein the thermocouple holder and the intermediate mounting member are made of metal, and the metal element having the highest component ratio of the intermediate mounting member is different from the metal element having the highest component ratio of the thermocouple holder. [Configuration 3] 3. The thermocouple mounting structure according to claim 2, wherein the metal element having the highest composition ratio in the intermediate mounting member is nickel, and the metal element having the highest composition ratio in the cylinder is iron. [Configuration 4] 2. The thermocouple mounting structure according to claim 1, wherein the intermediate mounting member is made of a material different from that of the cylinder. [Configuration 5] 5. The thermocouple mounting structure according to any one of claims 1 to 4, wherein the intermediate mounting member is a member in which a wire having a diamond-shaped cross section is wound into a coil shape. [Configuration 6] A thermocouple mounting structure according to any one of configurations 1 to 5, The cylinder; A thermocouple attached to the mounting structure; A mechanical device having the above construction. [Configuration 7] 7. The machine of claim 6, wherein the machine is an injection molding machine. [Method 1] A method for installing a thermocouple mounting structure on a cylinder for heating and melting a material, comprising the steps of: (A) attaching an intermediate mounting member having an outer thread groove on an outer surface and an inner thread groove on an inner surface to the cylinder by engaging the outer thread groove with a threaded hole provided in the cylinder; (B) screwing a thermocouple holder that holds a thermocouple into the inner screw groove of the intermediate mounting member; having The intermediate mounting member is made of a different material than the thermocouple holder. [Explanation of symbols]

[0034] 1 injection molding machine 4 Thermocouples 5 Thermocouple mounting structure 32 cylinders 38 screw holes 51 Thermocouple holder 52, 152 Intermediate mounting member 52A, 152A Outer Thread Groove 52B,152B Internal thread groove

Claims

1. A mounting structure for a thermocouple attached to a cylinder for heating and melting a material, comprising: an intermediate mounting member having an outer surface with an outer screw groove that engages with a screw hole provided in the cylinder and an inner surface with an inner screw groove; a thermocouple holder that is screwed into the inner screw groove of the intermediate mounting member and holds a thermocouple; having The intermediate mounting member is made of a material different from that of the thermocouple holder.

2. 2. The thermocouple mounting structure according to claim 1, wherein the thermocouple holder and the intermediate mounting member are made of metal, and the metal element having the highest component ratio of the intermediate mounting member is different from the metal element having the highest component ratio of the thermocouple holder.

3. 3. The thermocouple mounting structure according to claim 2, wherein the metallic element having the highest composition ratio in the intermediate mounting member is nickel, and the metallic element having the highest composition ratio in the cylinder is iron.

4. 2. The thermocouple mounting structure according to claim 1, wherein the intermediate mounting member is made of a material different from that of the cylinder.

5. 5. The thermocouple mounting structure according to claim 1, wherein the intermediate mounting member is a member formed by winding a wire having a rhombic cross section in a coil shape.

6. The thermocouple mounting structure according to any one of claims 1 to 4, The cylinder; A thermocouple attached to the mounting structure; A mechanical device having the above construction.

7. The machine of claim 6, wherein the machine is an injection molding machine.

8. A method for installing a thermocouple mounting structure on a cylinder for heating and melting a material, comprising the steps of: (A) attaching an intermediate mounting member having an outer thread groove on an outer surface and an inner thread groove on an inner surface to the cylinder by engaging the outer thread groove with a threaded hole provided in the cylinder; (B) screwing a thermocouple holder that holds a thermocouple into the inner screw groove of the intermediate mounting member; having The intermediate mounting member is made of a different material than the thermocouple holder.

Images