Hollow valve partial annealing machine

Abstract

Provided is a machine for partially annealing a friction pressure welding part of a hollow valve, characterized in that only a friction pressure welding part and a part thermally affected by friction pressure welding are annealed using a heating coil of a high-frequency heating system.

Description

[Technical Field]

[0001] The present invention relates to a partial annealing machine for annealing only the friction-welded portion and the heat-affected zone caused by friction welding as an annealing method after friction welding of the head member and shaft member of a hollow engine valve. [Background technology]

[0002] Conventionally, the annealing method used after friction welding of the head and shaft members of hollow valves has been batch processing in a heat treatment furnace. In this batch processing, hundreds to thousands of hollow valves are placed in a heat treatment furnace at the same time, and annealed at 600°C for about 1.5 hours using, for example, propane gas as a heat source. Summary of the Invention [Problem to be solved by the invention]

[0003] However, in batch processing using this heat treatment furnace, temperature control is limited to the temperature inside the furnace, and unless the temperature throughout the furnace is kept uniform, the annealing effect cannot be achieved. This means that temperature control is required for each amount of material put into the furnace, and there is a problem in that the temperature of the hollow valve itself cannot be controlled. Furthermore, batch processing using a heat treatment furnace requires time for loading hollow valves into the heat treatment furnace, performing the annealing operation, and then removing the hollow valves from the heat treatment furnace after annealing, which has been cited as a problem in that this process must be carried out outside of the hollow valve manufacturing process. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a partial annealing machine for hollow valves that can control the temperature of the hollow valves themselves and can perform in-line annealing of friction welded portions. [Means for solving the problem]

[0004] According to the present invention, the above problem is solved as follows. (1) This invention relates to a partial annealing machine for hollow valves, which is an annealing machine for annealing friction-welded portions of hollow valves, characterized in that it anneals only the friction-welded portions and heat-affected zones caused by friction welding.

[0005] (2) The invention relates to the partial annealing machine for hollow valves as described in (1) above, characterized in that the partial annealing machine is equipped with a heating coil using a high-frequency heating method.

[0006] (3) The invention relates to the partial annealing machine for hollow valves described in (1) or (2), characterized in that the heating cycle during partial annealing of the friction welded portion is managed using two radiation thermometers, one for temperature control and the other for temperature monitoring.

[0007] (4) The invention relates to the partial annealing machine for hollow valves described in (1) above, characterized in that the annealing temperature in the heating cycle during partial annealing of the friction welded portion is 700°C to 800°C, preferably 730°C to 780°C, and more preferably 740°C to 760°C.

[0008] (5) An invention relating to a temperature control system for a partial annealing machine for hollow valves, characterized in that the upper and lower limit temperatures for temperature monitoring in the heating cycle during partial annealing of hollow valves are 750±5°C. [Effects of the Invention]

[0009] According to the invention described in (1) above, it is possible to anneal only the friction-welded portion of the hollow valve itself and the heat-affected portion caused by the friction welding. This allows the hollow valve to be carried into the partial annealing machine, annealed, and then carried out in a short time, thereby realizing in-line annealing operations.

[0010] According to the invention described in (2) above, by adopting the high-frequency heating method, it has become possible to raise the temperature to the annealing temperature in about 2 seconds and to maintain the temperature in 8 seconds, and it has become possible to realize all of the operations of carrying the hollow valve into the partial annealing machine, raising the temperature, maintaining the temperature, and carrying it out within about 20 seconds.

[0011] According to the invention described in (3) above, one radiation thermometer controls the temperature of the temperature-raising operation and the temperature-keeping operation, and the other radiation thermometer monitors this temperature control, thereby ensuring that the temperature control is performed within the range of the upper and lower limit temperatures of the monitored temperature, thereby making it possible to ensure the annealing operation.

[0012] According to the invention described in (4) above, the high-frequency heating method is used, and the heating and temperature-holding time is short, so the annealing temperature is set relatively high to effectively remove residual stress from the friction-welded portion. In particular, by setting the annealing temperature at 740°C to 760°C, residual stress can be effectively removed.

[0013] According to the invention described in (5) above, by setting the upper and lower limit temperatures of the monitored temperature within the range of 750±5°C, it is possible to ensure temperature control of partial annealing and ensure the partial annealing operation. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a plan view of a partial annealing machine according to the present invention. [Figure 2] FIG. 1 is a side view of a partial annealing machine according to the present invention. [Figure 3] 3 is a diagram showing operations performed in the partial annealing machine body of the present invention. FIG. [Figure 4] FIG. [Figure 5] FIG. 2 is a perspective view of the heating coil assembly. [Figure 6] FIG. 2 is a diagram showing the annealing process of the partial annealing machine of the present invention. [Figure 7] 1 is an annealing temperature profile of a partial annealing machine of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same parts are designated by the same reference numerals.

[0016] 1 shows the overall configuration of a partial annealing machine 100 of the present invention for friction-welding the head member and shaft member of a hollow engine valve (hereinafter referred to as "work") and then partially annealing the friction-welded portion of the work 1. The partial annealing machine 100 is composed of a partial annealing machine main body 110, an operation panel 50, a control panel 60, a high-frequency power source 70, and a matching box 80.

[0017] As shown in FIG. 2, the partial annealing machine main body 110 includes a heating coil assembly 10, a first radiation thermometer 20, a second radiation thermometer 25, a work lifting unit 30, a stand 40, and the like.

[0018] The operation panel 50 displays the frequency of the high frequency power supplied during annealing, the output value of the heating power, and the measured temperature / control setting temperature / monitored temperature of the radiation thermometers 20 and 25. The output value of the heating power is changed using the operation panel 50.

[0019] The control panel 60 accommodates electrical control devices, electrical devices, electrical components, etc. for electrically controlling the partial annealing machine.

[0020] The high-frequency power supply 70 is a power supply that supplies high-frequency alternating current to the heating coil 11 (see FIG. 4) incorporated in the heating coil ASSY 10 in order to generate a high-frequency electromagnetic field in the heating coil 11. A matching box 80 is provided to prevent voltage and current bounce so that the alternating current flows efficiently from the high-frequency power supply 70 to the heating coil 11.

[0021] 1, a cooling water circulator 90 is provided in the vicinity of the partial annealing machine 100 in order to supply cooling water used in the heating coil 11. The cooling water circulator 90 ensures the supply temperature of the cooling water as well as the quality of the water.

[0022] 3 shows the operations (1) to (5) performed in the partial annealing machine main body 110. In the partial annealing machine main body 110, the operation of partially annealing the friction-welded portion of the workpiece 1, which is the purpose of the partial annealing machine, is performed in the following order: (1) workpiece loading, (2) workpiece inversion and installation in the lifting unit, (3) workpiece lifting and partial annealing, (4) workpiece lowering and workpiece inversion, and (5) workpiece removal. Each operation will be explained below.

[0023] (1) Workpiece loading The partial annealing process of the friction welded portion of the workpiece 1 follows the friction welding process of the umbrella member and shaft member, the deburring process of the friction welded portion, and the cleaning process. From the cleaning process, the workpieces 1 are clamped one by one in the workpiece loading hand chuck 31 and sent to the partial annealing machine. At this time, the workpieces 1 are clamped in the workpiece loading hand chuck 31 with the umbrella portion facing up.

[0024] (2) Installed in the workpiece inversion and lifting unit The workpiece 1 sent to the partial annealing process is sandwiched between the workpiece setting inversion unit 32, rotated 180° so that the head portion faces downward, and set on the workpiece lifting unit 30. Two workpieces 1 are set on the workpiece lifting unit 30. The number of workpieces 1 set on the workpiece lifting unit 30 may be one, three, or more depending on the production capacity of hollow engine valves.

[0025] (3) Workpiece lifting and partial annealing In the partial annealing machine main body 110, the heating coil ASSY 10 is installed at a position where, when the work lifting unit 30 on which two workpieces 1 are placed rises, the shaft portions of the two workpieces 1 are automatically inserted into the coil 15 of the heating coil 11. When the work lifting unit 30 rises while gripping the head portions of the workpieces 1 and the shaft portions of the two workpieces 1 are inserted into the workpiece insertion portions 18c, 18d of the heating coil ASSY 10, partial annealing begins. Temperature control during partial annealing is performed by a first radiation thermometer 20, and temperature monitoring during partial annealing is performed by a second radiation thermometer 25. Details of the heating coil 11 and the heating coil ASSY 10 will be described below using Figures 4 and 5, and details of temperature control during partial annealing will be described below using Figures 6 and 7.

[0026] (4) Workpiece lowering and workpiece inversion When the partial annealing operation of the friction welded portion is completed, the work lifting unit 30 descends, and the work 1 is clamped by the work removal inversion unit 33, rotated 180 degrees so that the umbrella portion is facing up, and placed on the work removal conveyor 34.

[0027] (5) Work removal The workpiece 1 is sent to the final inspection process by the workpiece discharge conveyor 34. During the inspection process, the head portion of the workpiece 1 is supported by the workpiece discharge conveyor 34, and the shaft portion is transported in a hanging-down state, so that the temperature of the friction-welded portion after partial annealing can be cooled by air.

[0028] 4 is a perspective view of the heating coil 11. The heating coil 11 includes a coil plate 12, a coil body 13, and a coil tube 14, and the coil tube 14 forms two coils 15.

[0029] The coil plate 12 is a part to which high frequency power for generating an electromagnetic field is supplied from a high frequency power supply 70, and the coil body part 13 connected to it supports the coil tube 14 and also plays a role in removing heat generated in the heating coil 11 by flowing cooling water through the coil body part 13. The material used for the coil plate 12 and the coil body part 13 is ordinary phosphorus deoxidized copper.

[0030] The coil body portion 13 has a cooling water inlet 16a for receiving cooling water and a cooling water outlet 16b for discharging cooling water, so that cooling water at a constant temperature flows through the coil body portion 13. This cooling water is supplied from a cooling water circulation device 90, and the cooling water that passes through the coil body portion 13 returns to the cooling water circulation device 90.

[0031] The coil tube 14 is inserted into and soldered to the tip of the coil body 13, and the surface of the tube is coated with insulating glass cloth. The material of the coil tube 14 is ordinary phosphorus-deoxidized copper.

[0032] The coil 15 generates a high-frequency electromagnetic field, which generates an induced current through electromagnetic induction in the workpiece 1 inserted into the coil 15, and the resulting Joule heat heats the workpiece 1 to the annealing temperature in a short time. In FIG. 4, the coil tube 14 is provided with two coils 15, but it may be provided with one coil, or three or more coils. This can be determined appropriately depending on the production capacity of hollow engine valves.

[0033] A Teflon (registered trademark) sheet 17 is sandwiched between the center of the coil plate 12 and the coil body 13 to insulate against short circuits of AC current in the heating coil 11. Assembling the heating coil 11 with this Teflon sheet 17 sandwiched between them not only provides an insulating effect, but also allows the heating coil 11 to be clamped and positioned.

[0034] 5 is a perspective view of the heating coil holder 18. The heating coil holder 18 forms the heating coil ASSY 10 by accommodating the heating coil 11. The heating coil 11 is attached to a holder plate 18a with screws, and the holder cover 18b is then placed over the heating coil ASSY 10. The holder plate 18a and the holder cover 18b are provided with workpiece insertion portions 18c and 18d for inserting the shaft portion of the workpiece 1 when the workpiece 1 is partially annealed.

[0035] The reason why the heating coil 11 is accommodated in the heating coil holder 18 and then installed in the partial annealing machine 100 is to prevent contact problems with the heating coil 11. That is, this is to prevent contact between the workpiece 1 and the coil 15 when inserting the workpiece 1 into the coil 15, and to prevent objects around the heating coil 11 from directly contacting the heating coil 11 while the partial annealing machine 100 is in operation.

[0036] The entire heating coil holder 18 is made of polyphenylene sulfide resin, a high-performance engineering plastic that is characterized by excellent heat resistance, flame retardancy, mechanical properties, dimensional stability, chemical resistance, and the like.

[0037] Fig. 6 shows the heating cycle during partial annealing in the partial annealing machine 100, and Fig. 7 shows the temperature profile of the friction-welded portion of the workpiece 1 during partial annealing. In Fig. 6, the 1st side shows the heating cycle for temperature control, and the 2nd side shows the heating cycle for temperature monitoring. The temperature profile of the friction-welded portion of the workpiece 1 during partial annealing in Fig. 7 shows the relationship between time and temperature in the heating cycle for temperature control on the 1st side of Fig. 6.

[0038] In the first heating cycle in Figure 6, "heating output [100%]" is a heating cycle that heats the friction welded part of Work 1 at 100% output, raising the temperature from room temperature to the set temperature of 750°C. By using high-frequency heating, it is possible to raise the temperature to 750°C in about 2 seconds (see Figure 7).

[0039] When the "Set temperature [750°C]" reaches the set temperature of 750°C through high-frequency heating, the 1st side starts a heat-keeping cycle, and the 2nd side starts temperature monitoring for the heat-keeping cycle. The 2nd side's "Upper and lower limit temperatures [750±5°C]" have upper and lower temperature monitoring limits of 750±5°C, and if the 1st side's heat-keeping temperature deviates from either the upper or lower limit, an alarm is sounded and the heat-keeping cycle is stopped.

[0040] "Keep warm temperature [749°C]" indicates that the temperature control is performed at 749°C during the keep warm cycle, and "Keep warm output / OFF output [70% / 30%]" indicates that the keep warm control during the keep warm cycle is performed on / off, with the output at 70% and 30%. Also, "Keep warm time [8 seconds]" indicates that the temperature is kept at 749°C for 8 seconds (see Figure 7).

[0041] From the temperature profile during partial annealing in Figure 7, The workpiece (hollow valve) is carried into the partial annealing machine. The workpiece is inserted into the heating coil by the workpiece lifting unit. Partial annealing begins, - Insert the food into the heating coil until the warming time [8 seconds] ends. The workpiece is removed from the heating coil by the workpiece lifting device. - Carried out from the partial annealing machine, This shows that the inspection is completed within approximately 20 seconds. During the transportation on the workpiece discharge conveyor 34 until the next inspection process, the temperature of the friction-welded portion is cooled by contact with the atmosphere. [Explanation of symbols]

[0042] 1 Work 10 Heating coil assembly 11 Heating coil 12 Coil Plate 13 Coil body 14 Coil Tube 15 coils 16a Cooling water inlet 16b Cooling water outlet 17 Teflon sheet 18 Heating coil holder 18a Holder plate 18b Holder cover 18c, 18d Work insertion part 20 1st radiation thermometer 25 2st radiation thermometer 30 Work lifting unit 31 Workpiece loading hand chuck 32 Workpiece installation inversion unit 33 Workpiece removal inversion unit 34 Work unloading conveyor 40 Mounting stand 50 Control panel 60 Control Panel 70 High frequency power supply 80 Matching Boxes 90 Cooling water circulation system 100 Partial annealing machine 110 Partial annealing machine body

Claims

1. 1. A partial annealing machine for annealing a friction-welded portion of a hollow valve, the annealing machine comprising: a workpiece installation inversion unit that inverts the hollow valve; a workpiece lifting unit that raises and lowers the hollow valve; and a workpiece removal inversion unit that removes the hollow valve from the workpiece lifting unit, the machine annealing only the friction-welded portion and a heat-affected zone caused by friction welding.

2. 2. The partial annealing machine for hollow valves according to claim 1, wherein the partial annealing machine is provided with a heating coil using a high-frequency heating method.

3. 3. The partial annealing machine for hollow valves according to claim 1, wherein temperature control in the heating cycle during partial annealing of the friction welded portion is performed by using two radiation thermometers, one of which controls the temperature and the other of which monitors the temperature.

4. 2. The partial annealing machine for hollow valves according to claim 1, wherein the annealing temperature in the heating cycle during partial annealing of the friction-welded portion is 700°C to 800°C, preferably 730°C to 780°C, and more preferably 740°C to 760°C.

5. 2. The partial annealing machine for hollow valves according to claim 1, wherein the upper and lower limit temperatures for monitoring the temperature in the heating cycle during partial annealing of hollow valves are 750±5°C.

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