JP2009161785A - Heat treatment equipment for sizing press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide heat treatment equipment for continuously quenching machine parts made of ferrous sintered alloy and satisfactorily sizing the parts using a sizing press while a temperature not lower than the martensitic transformation starting point and not higher than the austenitizing temperature is maintained and to make it possible to attain correct and smooth operation of a conveying system and prevent the damage of a workpiece during conveyance by preventing the occurrence of scooping motion during the operation of devices constituting the conveying system. <P>SOLUTION: Continuous heat treatment equipment includes a quenching conveying system 4 by which a workpiece W heated in a heating furnace 1 is fed into a quenching oil tank 12 and then drawn up out of the tank. With respect to a feeding mechanism 13, a rotary table 15 and a take-out device, each constituting the quenching conveying system, a horizontal cylinder 13a as a drive source of the feeding mechanism 13, a drive source of the rotary table 15, and a lifting mechanism of the take-out device are constituted of a hydraulic cylinder, a servo motor 15a, and a ball screw and a servomotor, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat treatment facility for a sizing press for continuously and smoothly performing heat treatment and sizing of a machine part formed of an iron-based sintered alloy.

  Machine parts made of iron-based sintered alloys that increase the strength and hardness by heat treatment, when subjected to heat treatment after sizing or coining, the residual stress during sizing and coining is released in the heat treatment process, resulting in a significant reduction in dimensional accuracy To do. Therefore, in order to eliminate the problem, the present applicant heated an iron-based sintered body having a martensite transformation start point (Ms point) in a temperature range of 50 to 350 ° C. at a temperature (Ael point) higher than the austenitizing temperature. The following patent describes a method of sizing or coining after quenching at a cooling rate at which martensitic transformation appears after austenite formation, and when the temperature of the quenched body reaches a temperature range between the Ms point and the Ael point. Patent Document 2 proposes a warm sizing facility that is proposed by Document 1 and further includes a heat treatment apparatus for carrying out the method.

  The sizing equipment proposed in Patent Document 2 conveys workpieces supplied to the sizing press through the supply unit, the heating furnace, the cooling unit, and the discharge unit one by one from the supply unit to the press input unit. A continuous heat treatment apparatus (a heat treatment facility for sizing press referred to in the present invention) provided with a conveying apparatus for conveying the workpieces one by one in synchronization with the sizing process.

Specifically, the transport device of this equipment includes a transport mechanism (for example, a belt conveyor) that intermittently feeds the work in the heating device, and a cooling unit connected to the outlet of the heating device with the work at the head position on the transport mechanism. An input mechanism for charging into the oil filling tank, a work holder provided in the quenching oil tank, a rotary table for moving the work holder alternately between the work receiving part and the take-out part in the quenching oil tank, and the take-out part A quench transfer device combined with a take-out device that takes out the workpiece holder moved from the quenching oil tank, and a discharge device that receives the work taken out from the quench oil tank and moves it to the press input unit, The charging mechanism, the rotary table, and the take-out device that make up the quenching and conveying device are all driven by an air cylinder that uses compressed air as a power source, Chueta, it has been performed in an air equipment such as an air chuck. Further, the operation of the transfer device is time-controlled, and the movement of each part is synchronized with the sizing processing time.
JP-A-7-138613 JP 2004-137539 A

  Air has a higher compression ratio than liquid. For this reason, the throwing mechanism and the lifting mechanism using the air device as a drive source are likely to be caught in an awkward movement (so-called squeezing), and the work may not be smoothly taken out from the quenching oil tank.

  In addition, when the operation speed of the air device is increased, it is necessary to physically perform the stop operation using a stopper or the like, and the impact at the time of the stop increases, so that the workpiece is easily deformed or damaged. For example, when the rotary table in the quenching oil tank is rotated at a high speed and suddenly stopped by the stopper, the work stored in the work holder moves by inertia and collides with the inner wall of the holder. Even when the workpiece holder is taken out of the quenching oil tank with the lifting mechanism, if the lifting mechanism is moved at a high speed and stopped suddenly, the workpiece will jump in the workpiece holder and an impact will be applied to the workpiece, which will be deformed or damaged. Cause.

  In addition, timing of the operation of the devices to be interlocked with each other when the air device is crushed occurs, and since the time control of the transfer device is performed, the stability of the operation of each device is impaired. For this reason, troubles such as the conveyance becoming unstable and uncertain and having to stop the conveyance device occur, leading to a reduction in the operating rate of the heat treatment equipment.

  An object of the present invention is to solve the above-mentioned problems and to prevent the operation rate of the heat treatment equipment from being lowered and to prevent damage to the work so that the operation of the transfer device is performed accurately and smoothly.

  In order to solve the above problems, in the present invention, among the devices constituting the quenching and conveying apparatus of the heat treatment facility disclosed in Patent Document 2, the drive source of the input mechanism is a hydraulic cylinder (or electric cylinder), The rotary table drive source is constituted by a servo motor, and the lifting mechanism of the take-out device is constituted by a servo motor and a ball screw.

  It is preferable to use a gas (denaturing gas such as nitrogen gas) that becomes a non-oxidizing atmosphere inside the heating furnace of the heat treatment equipment.

The hydraulic cylinder or electric cylinder is used as the drive source for the charging mechanism included in the quenching transfer device, the servo motor is used as the drive source for the rotary table, and the lifting mechanism of the take-out device is composed of a servo motor and a ball screw. The feeding mechanism, the rotary table, and the lifting mechanism are not sucked during operation. Accordingly, there is no timing deviation of the operation due to the device scrambling. For this reason, the movement of the entire transfer apparatus is harmonized, the transfer apparatus is not stopped, and the operating rate of the heat treatment equipment is improved.

  In addition, hydraulic cylinders, electric cylinders, and servo motors can be stopped slowly by controlling their speed, so that no impact is applied to the workpiece being processed, and there is no problem of deformation or damage to the workpiece due to impact at the time of stopping. Can do.

Embodiments of a heat treatment facility for a sizing press according to the present invention will be described below with reference to FIGS.
Based on An exemplary heat treatment facility includes a heating furnace 1, a cooling unit 2 connected to the outlet of the heating furnace, a transport mechanism 3 drawn into the heating furnace 1, and a quenching transport device 4 provided in the cooling unit 2. And a discharge device 5 for conveying the workpiece W (a machine part formed of an iron-based sintered alloy) W received from the quenching and conveying device 4 toward the press-in portion 6. The workpiece W moved to the press input unit 6 is supplied to a sizing press 7 and subjected to a sizing process.

  The heating furnace 1 has a stirring fan 8 for uniforming the temperature distribution inside and a heat source 9 for heating, and the internal temperature can be controlled. The heat source 9 of the heating furnace 1 can employ an electric heater, an induction heating device, or the like.

  The cooling unit 2 has a cooling chamber 2a covered with a cover 10, and a quenching oil tank 12 having a guide 11 is provided inside the cooling chamber 2a. Moreover, the inside of the cooling chamber 2a is made into a non-oxidizing atmosphere using the same atmospheric gas as the heating furnace 1.

  The transport mechanism 3 employed here is a heat-resistant conveyor using a metal mesh belt, and intermittently feeds the supplied workpiece W and moves it toward the furnace outlet. The illustrated transport mechanism 3 transports the workpieces W in two rows, but the workpieces can be transported in a single row.

  The quenching / conveying device 4 includes a loading mechanism 13, a work holder 14, a rotary table 15, and a take-out device 16.

  The feeding mechanism 13 is provided with two sets of the same ones corresponding to the workpieces transported in two rows, and carries the workpieces alternately. The throwing mechanism 13 has a horizontal cylinder 13a and a vertical cylinder 13b serving as driving sources. The scraper 13c is driven by the two cylinders, and the workpiece W is scraped off and thrown into the quenching oil tank 12. . The horizontal cylinder 13a of the drive source adopted for the closing mechanism 13 is a hydraulic cylinder (an electric cylinder may be adopted instead), and the speed can be controlled by the controller. hard. Since the vertical cylinder 13b does not require fine movement, an air cylinder may be used.

  The rotary table 15 supports the workpiece holder 14, and rotates the workpiece by a predetermined angle with the vertical axis as a fulcrum, and moves the workpiece holder 14 that has received the workpiece to the take-out portion. The rotary table 15 uses a servo motor 15a as a drive source.

  The take-out device 16 includes a holder 17 that holds the workpiece holder 14 on the rotary table 15 when the workpiece is taken out from the quenching oil tank, an elevating mechanism 18 that moves the holder 17 up and down, and a tilting mechanism 19 that tilts the holder 17. It has. Since the holder 17 does not give an impact to the workpiece, an air chuck that is advantageous in terms of cost may be used. The elevating mechanism 18 combines a ball screw 18a and a servo motor 18b that rotates the ball screw, connects a support member 18d to a slider 18c that is screwed to the ball screw 18a, and attaches a holder 17 to the support member 18d. . The slider 18c moves up and down by forward and reverse rotation of the ball screw 18a, and the holding tool 17 enters the quenching oil tank 12 and grips the work receiving tool 14 when lowered.

  The discharge device 5 is constituted by a belt conveyor (also a conveyor using a metal mesh belt), and the work W that has exited the cooling chamber 2a is sent to the press input unit 6 one by one by the discharge device 5. . The discharge device (belt conveyor) 5 is covered with a cover 20 except for the inlet and outlet in order to maintain the temperature of the workpiece W. When the conveying distance by the discharge device 5 is long, it is preferable to introduce hot air generated by the hot air generator 21 into the cover 20. An electric heater, a gas burner, or the like can be used in place of the hot air generator 21. Even in such a case, the internal temperature of the cover 20 can be kept constant and the temperature drop of the workpiece W can be suppressed.

  The sizing press 7 is a well-known facility in which a die set having a sizing die is attached to a press machine. The mold of the sizing press 7 may be either one having a forced cooling function or one having no forced cooling function.

  The workpiece W moved to the press input unit 6 may be transferred to the sizing press 7 manually, or the operation may be mechanized using a robot hand or the like.

  Further, in order to prevent the work from being damaged on the surfaces of the guide 11, the work holder 14, the shooter 16 a, and the press-in portion 6, which are in contact with the work while falling, for example, heat resistance such as silicon resin or fluororesin is used. It is advisable to paste some cushioning material.

  As described in Patent Document 2, the heat treatment equipment configured as described above feeds the work W placed on the transport mechanism 3 in the work supply unit S to the heating furnace 1 and heats it to a target temperature of, for example, about 850 ° C. Next, when the workpiece W heated to the target temperature reaches a predetermined position, the throwing mechanism 13 is operated, and the workpiece W at the head position on the conveyor is quenched in the quenching oil tank 12 by the scraping tool 13c that moves downward and forward. Scrap it off. Since the input mechanism 13 uses a hydraulic cylinder as a drive source, it can perform a smooth input without crushing. After confirming the input by the second input mechanism, the transport mechanism 3 is driven to move the next workpiece W to the leading position of the conveyor, and waits until the next input instruction is received together with the returned input mechanism 13.

  The workpiece W dropped into the quenching oil tank 12 is guided by the guide 11 and is stored in the workpiece holder 14 below the oil level. The workpiece W is taken out from the quenching oil tank 12 after a predetermined quenching time has elapsed. The quenching time is controlled to stabilize the quality of the workpiece.

  Here, the work W is taken out from the quenching oil tank 12 in the following procedure. That is, the rotary table 15 in which the workpiece W is accommodated in the workpiece holder 14 that has been waiting in the workpiece receiving portion is driven, the holder 17 is operated, and the workpiece holder 14 is gripped by the holder 17. Thereafter, the elevating mechanism 18 is operated, and the workpiece W is pulled up onto the quenching oil tank 12 together with the workpiece holder 14.

  The stop of the rotary table 15 and the lifting by the elevating mechanism 18 during the take-out process are performed by controlling the rotation of the servo motors 15a and 18b serving as driving sources, and no impact is applied to the workpiece.

  The work W pulled up onto the quenching oil tank 12 is moved onto the discharging mesh belt conveyor of the discharging device 5 by tilting the work receiving member 14 and sent to the press input unit 6.

  The conveyance mechanism 3, the quenching conveyance device 4, and the discharge device 5 of the conveyance device that moves the workpiece W from the supply unit to the press input unit may be feedback control that is controlled by cycle time.

  The workpiece W sent to the press input unit 6 is set on the sizing press 7 by an operator or a robot hand and subjected to sizing processing. Since the sizing process is preferably performed while the workpiece W is maintained at a temperature of 180 ° C. or higher, as proposed in Patent Document 2, the workpiece W leaves the quenching oil tank 12 and immediately before the sizing is performed. It is preferable to determine whether or not the sizing is possible based on whether the time exceeds the target time. It may be possible to determine whether or not sizing is possible by measuring the temperature of the workpiece just before it is put into the sizing press with a radiation thermometer, etc. By using such a method, sizing work that has a high defect occurrence rate and is wasted Can be made.

The top view which simplifies and shows embodiment of the heat processing equipment of this invention Sectional drawing along the AA line of FIG. Sectional drawing along the BB line of FIG. Sectional view along line CC in FIG. Sectional drawing along the DD line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Cooling part 2a Cooling chamber 3 Conveying mechanism 4 Quenching conveying apparatus 5 Discharging apparatus 6 Press input part 7 Sizing press 8 Stirring fan 9 Heat source 10 Cover 11 Guide oil quenching tank 13 Input mechanism 13a Horizontal cylinder 13b Vertical cylinder 13c Scraping tool 14 Work receiving tool 15 Rotary table 15a Servo motor 16 Picking device 16a Shutter 17 Holding tool 18 Lifting mechanism 18a Ball screw 18b Servo motor 18c Slider 18d Support member 19 Tilt mechanism 20 Cover 21 Hot air generator

Claims (2)

There is a transport device that transports workpieces (W) supplied to the sizing press (7) from the heating furnace (1) of the continuous heat treatment device through the cooling unit (2) one by one toward the press input unit (6). And
The conveying device (3) intermittently feeds the workpiece (W) in the heating furnace (1), and the workpiece (W) at the head position on the conveying mechanism is a quenching oil tank of the cooling unit (2). (12) An input mechanism (13) to be put into the inside, a rotary table (15) for moving the work holder (14) to the take-out section in the quenching oil tank (12), and a work holder moved to the take-out section A quenching transfer device (4) combined with a take-out device (16) for taking out a quenching oil tank (12),
It is configured by combining a discharge device (5) that receives the workpiece (W) taken out from the quenching oil tank (12) and moves it to the press input section (6),
The drive mechanism of the input mechanism (13) is a hydraulic cylinder or an electric cylinder, the drive source of the rotary table (15) is a servo motor (15a), and the lifting mechanism (18) of the take-out device (16) is a servo motor (18a). ) And a ball screw (18b).   The heat treatment equipment for a sizing press according to claim 1, wherein the inside atmosphere of the heating furnace (1) is a non-oxidizing atmosphere.

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