JP3930160B2 - Method and apparatus for controlling forging die - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for controlling a forging die in which a forging material is loaded in a cavity and forging can be performed under the pressurizing action of a punch.
[0002]
[Prior art]
Conventionally, a forging material is inserted into a cavity formed in an upper die and a lower die joined together, and the forging material is forged into a predetermined shape by applying pressure to the forging material via a punch. Forging dies to be molded are known.
[0003]
By the way, the present applicant has proposed a forging die apparatus provided with a buffer mechanism for absorbing a surplus displacement amount until the punch comes into contact with the lower die and reaches the bottom dead center (Japanese Patent Application No. Hei. 9-335923).
[0004]
This buffer mechanism has a piston that is displaceably provided along a pressure chamber filled with a pressure fluid (pressure oil), and the punch is brought into contact with the lower die under the displacement action of the piston, and the bottom dead center. The surplus displacement amount until the pressure reaches the pressure chamber is suitably absorbed by the pressure fluid (pressure oil) filled in the pressure chamber.
[0005]
[Problems to be solved by the invention]
The present invention has been made in connection with the above proposal, and prevents the mold from being damaged even when the upper mold and the lower mold come into contact with each other when the forging material is not loaded in the cavity. An object of the present invention is to provide a method and apparatus for controlling a forging die capable of improving the durability of the die.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention is provided with a buffer mechanism for absorbing a surplus displacement amount from when the first mold member and the second mold member come into contact with each other until reaching the bottom dead center. A method for controlling a forging die,
  The first mold memberAfter the forging material is loaded into the cavity provided in the first die member, the punch provided on the second mold member is displaced, the punch comes into contact with the forging material, and forging molding for the forging material is started.Before the first mold member and the second mold member come into contact with each other, it is detected whether or not the pressure of the pressure fluid filled in the pressure chamber constituting the buffer mechanism has reached the initial set pressure in the initial stage of molding. When the pressure fluid does not reach the initial set pressure, the pressure fluid filled in the pressure chamber is forcibly led out to the outside because the forging material is not loaded.
[0007]
In this case, the pressure fluid filled in the pressure chamber is made of pressure oil, and the pressure fluid is led out by energizing the electromagnetic valve to release the relief pressure of the relief valve.
[0008]
Further, when the pressure of the pressure fluid filled in the pressure chamber is detected and the pressure fluid is out of a predetermined filling pressure range, the relative displacement between the first mold member and the second mold member is stopped. The
[0009]
  further,After the punch comes into contact with the forging material and starts forging the forging material,The first mold member and the second mold member;IsThe abutment load when contactingBy load sensorDetectBased on a detection signal derived from the load sensor, it is determined whether or not the forging material has been forged to a predetermined thickness.
[0010]
Furthermore, the relief pressure of the pressure fluid in the pressure chamber from the time when the first die member and the second die member come into contact until reaching the bottom dead center is detected, and the relief pressure is within a predetermined range. If it is outside, the relative displacement between the first mold member and the second mold member is stopped.
[0011]
The air mixed in the pressure fluid in the pressure chamber is removed to the outside together with the pressure fluid leaking from the pressure chamber under the urging action of the air vent circuit.
[0012]
  Furthermore, the present invention provides the forging material by relatively displacing the first die member and the second die member and applying pressure to the forging material loaded in the cavity.AgainstForgingIs started and the first mold member and the second mold member are brought into contact with each other before reaching the bottom dead center.A control device for a forging die,
  The first mold member and the second mold member are relatively displaced, and the first mold member and the second mold member are brought into contact with each other by the action of the pressure fluid filled in the pressure chamber, and then the bottom dead center is reached. A buffer mechanism that absorbs the amount of displacement of the surplus until it reaches,
  Pressure detecting means for detecting the pressure of the pressure fluid filled in the pressure chamber;
  Based on the detection signal output from the pressure detection means, the pressure of the pressure fluid filled in the pressure chamber constituting the buffer mechanism isThe first mold member and the second mold member are in contact with each other after the forging process for the forging material is started.A pressure fluid control means for deriving the pressure fluid filled in the pressure chamber to the outside as if the forging material is not loaded when the initial set pressure in the initial stage of molding is not reached;
  It is characterized by providing.
[0013]
In this case, the pressure fluid control means includes a relief valve having an inlet port communicating with the pressure chamber, and an electromagnetic valve connected to the relief port of the relief valve and releasing the relief pressure of the relief valve under a switching action. Is included.
[0014]
The pressure detecting means comprises a pressure sensor, and a load sensor for detecting whether or not the first mold member and the second mold member are in contact with each other is provided separately from the pressure sensor.
[0015]
In addition, an air vent circuit for removing air mixed in the pressure fluid composed of the pressure oil in the pressure chamber is provided, and the air mixed in the pressure fluid is removed from the pressure chamber under the urging action of the air vent circuit. It is preferable to lead out together with the leaked pressure fluid. In addition, it is preferable to provide a pressure control valve for controlling the pressure of the pressure fluid supplied to the relief chamber of the relief valve.
[0016]
According to the present invention, if the pressure of the pressure fluid filled in the pressure chamber does not reach the initial set pressure in the initial stage of molding through the pressure fluid control means, the forging material is assumed to be unloaded. The pressure fluid filled in the pressure chamber is led out to the outside. Therefore, even if the upper die and the lower die come into contact with each other when the forging material is not loaded in the cavity, the die is not damaged and the durability of the die is improved.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The forging die control method according to the present invention will be described in detail below with reference to the accompanying drawings by giving a preferred embodiment in relation to a control device for carrying out the same.
[0018]
FIG. 1 shows a forging die 11 in which a hydraulic control apparatus 10 according to the present embodiment is incorporated.
[0019]
The forging die 11 includes a first die holder 14 in which a plurality of guide means 12a to 12d are erected in the vicinity of the four corners, and a second die layer provided in a laminated manner at the center of the first die holder 14. A die holder 16 and a third die holder 18 are included.
[0020]
An integrally formed thick press-fitting ring 20 is fixed on the second die holder 16 via fastening means 22, and a thin-walled sleeve 24 is inserted into the hole of the press-fitting ring 20. Thus, the upper die 26 and the lower die 28 are joined together.
[0021]
In the annular recess 30 formed on the upper side of the press-fitting ring 20, a first ring body 34 having a hole 32 formed therein, a second ring body 36 fitted on the first ring body 34, and A fastening ring 38 for holding the first ring body 34 and the second ring body 36 is provided. The first ring body 34 and the second ring body 36 are formed on the upper side of the press-fitting ring 20 and are press-fitted with good concentricity into a hole 37 concentrically processed with a cavity 46 described later. In this case, the first ring body 34 and the second ring body 36 may be integrally formed as a ring body without being configured separately.
[0022]
A top plate of the upper die 26 and the sleeve 24 is provided with a first plate 44 that regulates a displacement amount of the punch 40 by abutting with a second plate 42 that is integrally displaced with the punch 40 described later. The upper die 26 and the lower die 28 including the first plate 44 function as a first mold member.
[0023]
As shown in FIG. 4, the first plate 44 is provided with a load sensor 45 that detects whether or not the forming load by the punch 40 is reliably applied to the forging material. In this case, the load sensor 45 detects that the second plate 42 that is displaced integrally with the punch 40 has hit the first plate 44, and introduces a detection signal output from the load sensor 45 to a controller (not shown). Thus, the controller determines whether the first plate 44 and the second plate 42 are in contact with each other and the displacement amount of the punch 40 is restricted, and the forging material is forged to a predetermined thickness.
[0024]
The first ring body 34 is in a state of being strongly tightened toward the center by a second ring body 36 formed of, for example, a super hard material and subjected to a shrink fitting process. Further, the first ring body 34 and the second ring body 36 are press-fitted into a hole 37 concentrically processed with the cavity 46, and the taper portion of the fastening ring 38 is screwed into the screw hole of the press-fit ring 20. By being tightened, the cavity 46 is integrally joined to the recess 30 of the press-fitting ring 20 with good concentricity.
[0025]
In this case, a cavity 46 is formed by the upper die 26 and the lower die 28, and a knockout pin 48 for extruding a forged product is formed in the second die holder 16 and the third die holder 18 on the lower side of the cavity 46. It is arranged along the portion 50 so as to freely advance and retract. The cavity 46 is filled with a secondary molded product 52 as shown in FIG. 8 as a forging material.
[0026]
Above the press-fitting ring 20, there is provided an elevating part 54 that is connected to a ram of a mechanical press (not shown) and is displaced along the vertical direction integrally with the ram under the driving action of the mechanical press.
[0027]
This lifting part 54 starts forging forming when the punch 40 comes into contact with the forging material, and ends the forging forming for the forging material by contacting the upper die and the lower die before reaching the bottom dead center, Thereafter, a buffer mechanism 56 for absorbing a surplus displacement until reaching the bottom dead center is provided.
[0028]
The buffer mechanism 56 has a pressure chamber 58 formed therein, and has a bottomed cylindrical block body 62 having a piston 60 provided so as to be displaceable in the vertical direction along the pressure chamber 58, and the block body 62. It includes a set of connecting blocks 66a and 66b that are liquid-tightly connected and in which a passage 64 communicating with the pressure chamber 58 is formed. A ring-shaped stopper 68 for preventing the piston 60 from descending is fixed to the bottom surface of the block body 62.
[0029]
A ring-shaped high-pressure packing 72, a low-pressure packing 74, and a wear plate 76 are mounted on the outer periphery of the piston 60 via an annular groove. A punch plate 78 is fixed to the bottom surface of the piston 60, and the punch 40 is fixed to the punch plate 78 via a holder 80 surrounding a part of the outer peripheral surface. A guide sleeve 82 made of a cylindrical metal material is fitted on the outer periphery of the holder 80, and a second plate 42 is fixed to the bottom surface of the holder 80.
[0030]
The guide sleeve 82 is preferably formed of a metal material such as SKD11, FC25, or FC30, and the first ring body 34 is preferably formed of a material harder than the guide sleeve 82.
[0031]
The holder 80 including the punch 40, the guide sleeve 82, the second plate 42, and the like function as a second mold member. The punch 40 is provided so as to be displaceable along the vertical direction integrally with the elevating part 54 under the guiding action of the plurality of guide means 12 a to 12 d erected on the first die holder 14.
[0032]
As shown in FIG. 1, the hydraulic control device 10 according to the present embodiment is fixed to one connection block 66a via a seal member 100, and a pipe line such as a tube is connected to the hydraulic control device 10. The hydraulic pressure source 102 is connected via
[0033]
As shown in FIG. 3, the hydraulic control device 10 includes a relief valve 104, and the relief valve 104 has an inlet port 106 communicating with a pressure chamber 58 in which a piston 60 is accommodated via a passage 64, and a discharge valve. The outlet port 112 communicates with the tank 110 of the hydraulic power source 102 via the passage 108, and the relief port 116 supplies the relief pressure to a relief chamber (not shown) via the relief pressure supply passage 114.
[0034]
In the middle of the passage 64, a supply passage 118 is connected to supply pressure oil stored in the tank 110 of the hydraulic power source 102 to the pressure chamber 58 via a check valve 117 for pilot operation. A pressure sensor (pressure detection means) 121 for detecting the hydraulic pressure of the pressure oil in the pressure chamber 58 is connected via the. In place of the pressure sensor 121, a set of pressure sensors (not shown) is used, detection signals output from the set of pressure sensors are introduced into a controller (not shown), and AND of the set of detection signals is calculated. Alternatively, it may be detected.
[0035]
In the relief valve 104, the inlet port 106 and the outlet port 112 communicate with each other when the hydraulic pressure of the pressure oil filled in the pressure chamber 58 exceeds the hydraulic pressure of the pressure oil filled in the relief chamber and a valve body (not shown) is displaced. On the other hand, when the hydraulic pressure of the pressure oil filled in the pressure chamber 58 is equal to or lower than the hydraulic pressure of the pressure oil filled in the relief chamber, the valve closed state in which the communication between the inlet port 106 and the outlet port 112 is blocked. It is comprised so that it may become.
[0036]
A high pressure accumulator 124 is connected to the passage 120 branched from the relief pressure supply passage 114 via a check valve 122 for pilot operation, and a low pressure accumulator is connected to the passage 126 branched from the discharge passage 108. 128 is connected. The low-pressure accumulator 128 is connected to the supply passage 118 via a check valve 123 for pilot operation. The low-pressure accumulator 128 is preferably a large-capacity piston type, and the high-pressure accumulator 124 is preferably a balloon type.
[0037]
The check valve 122 is normally in a valve open state, and has a function of protecting the high pressure accumulator 124 by holding the internal pressure of the high pressure accumulator 124 by closing the valve under a pilot pressure supply operation. .
[0038]
The pressure chamber 58 is connected to an input side of an air vent circuit 127 for removing air mixed in the pressure oil filled in the pressure chamber 58 via a passage 125, and an output side of the air vent circuit 127 is It is connected to the discharge passage 108 via the passage 129.
[0039]
This air vent circuit 127 has an air vent valve 131 made up of a normally open type electromagnetic valve, and when the air vent valve 131 is in an open state, the pressure is released together with a small amount of pressure oil leaking from the pressure chamber 58. It functions to discharge air mixed in oil to the tank 110 through the discharge passage 108. As a result, the air in the pressure oil filled in the pressure chamber 58 is removed.
[0040]
The relief pressure supply passage 114 is guided by the pressure oil stored in the relief chamber of the relief valve 104 to the discharge passage 108 under the switching action of the relief pressure release valve 133 formed of an electromagnetic valve. A relief pressure release circuit 135 is provided to make the relief set pressure of the valve 104 zero. A passage 137 communicating with the relief pressure supply passage 114 is connected to the input side of the relief pressure release valve 133, while a passage 139 communicating with the discharge passage 108 is connected to the output side. Reference numeral 141 indicates a check valve.
[0041]
In this case, the relief valve 104, the relief pressure relief valve 133, and a controller (not shown) function as pressure fluid control means.
[0042]
The hydraulic source 102 includes a tank 110 in which pressure oil is stored, a first hydraulic pump 132 that feeds pressure oil through a supply passage 118 under the driving action of the electric motor 130, and under the driving action of the electric motor 130. And a second hydraulic pump 134 for supplying pressure oil to the relief chamber of the relief valve 104 via the relief pressure supply passage 114.
[0043]
A pressure control valve 136 for controlling the relief pressure of the relief valve 104 based on a relief pressure control signal introduced from a controller (not shown) is interposed between the second hydraulic pump 134 and the relief valve 104. .
[0044]
The forging die 11 incorporating the hydraulic control device 10 according to the embodiment of the present invention is basically configured as described above. Next, forging by the forging die 11 The material forming process will be described. In addition, the case where the outer cup which comprises a constant velocity joint as a forging product is forge-molded is demonstrated below as an example.
[0045]
By subjecting the cylindrical billet 84 as shown in FIG. 5 to primary forging by a mold device (not shown), the diameters are different via the intermediate step as shown in FIG. A primary molded product 86 is obtained. Subsequently, after preforming the primary molded product 86 (see FIG. 7), secondary forging is performed by another mold device (not shown), which is shown in FIG. A secondary molded product 52 composed of the cup portion 88 and the shaft portion 90 is obtained. The forging die 11 is further subjected to the third forging by using the second molded product 52 as a forging material.
[0046]
First, as a preparatory work, the upper die 26, the lower die 28, the sleeve 24, the press-fit ring 20 and the like are integrally assembled in a state where the guide sleeve 82 is inserted into the hole 32 of the first ring body 34, thereby The punch 40 is positioned with respect to the cavity 46 formed in the die 26 and the lower die 28.
[0047]
The pressure chamber 58 is filled with pressure oil having a predetermined hydraulic pressure through the supply passage 118 and the passage 64 under the driving action of the first hydraulic pump 132. In addition, pressure oil is supplied to the relief chamber (not shown) of the relief valve 104 through the relief pressure supply passage 114 under the driving action of the second hydraulic pump 134 to set a predetermined relief pressure. The relief set pressure is controlled by a pressure control valve 136 based on a relief pressure control signal introduced from a controller (not shown).
[0048]
Furthermore, when a protection circuit (overload mechanism) (not shown) is activated when an overload occurs, it takes time to return to the normal operation state, and continuous forging cannot be performed. The molding load for the forging material is set so as to be supported by the pressure oil filled in the pressure chamber 58.
[0049]
Next, in a state where the punch 40 is disposed at a rising position (initial position) (not shown), the secondary molded product 52 which is a forging material is loaded into the cavity 46. Then, the punch 40 is lowered integrally with the elevating part 54 connected to the ram under the driving action of a mechanical press (not shown), and the forging is started when the state shown in FIG. 1 is obtained.
[0050]
When the punch 40 is lowered integrally with the elevating part 54, the lateral load is favorably absorbed by the plurality of guide means 12 a to 12 d provided between the elevating part 54 and the first die holder 14. The punch 40 can be smoothly press-fitted into the centers of the holes 32 of the first and second ring bodies 34 and 36 disposed coaxially with the cavity 46 via the guide sleeve 82.
[0051]
When starting forging, the guide sleeve 82 fitted on a part of the outer peripheral surface of the punch 40 is guided by an annular groove (not shown) formed at the upper end of the hole 32 of the first ring body 34. When the punch 40 is further lowered, the punch 40, the holder 80 and the guide sleeve 82 are integrally displaced while being press-fitted into the hole 32 of the first ring body 34.
[0052]
Here, the relationship between the displacement of the punch 40 and the pressure oil filled in the pressure chamber 58 is shown in FIG. In FIG. 9, a curve A indicated by a solid line is a displacement amount of the punch 40 that is integrally displaced with the ram under the driving action of a mechanical press (not shown), and a curve B indicated by a two-dot chain line is filled in the pressure chamber 58. The pressure value (hydraulic pressure) of the pressurized oil, and the curve C indicated by the alternate long and short dash line is the separation distance D between the second plate 42 provided on the displacement side and the first plate 44 provided on the fixed side (see FIG. 1). Respectively.
[0053]
A ram of a mechanical press (not shown) is displaced downward from a predetermined ascending position, and the punch 40, the second plate 42 and the like are lowered integrally with the ram, whereby the first plate 44 on the fixed side. And the distance D between the second plate 42 on the displacement side gradually decreases. Note that the piston 60 is held by the stopper 68 and is prevented from being displaced downward, and the hydraulic pressure of the pressure oil filled in the pressure chamber 58 is a load applied to the punch 40 after the start of molding. As it increases, it gradually rises.
[0054]
Immediately before the punch 40 further descends and reaches the bottom dead center from the state shown in FIG. 1, the second plate 42 contacts the first plate 44, that is, the separation distance D between the first plate 44 and the second plate 42. Is 0, the displacement of the punch 40 toward the lower side is regulated, the thickness of the forging material is regulated precisely, and the forging is completed.
[0055]
Further, when the punch 40 is lowered by a small distance and the hydraulic pressure in the pressure chamber 58 reaches the relief set pressure, the relief valve 104 is opened, and the pressure oil in the pressure chamber 58 is discharged to the outside and the piston 60 is discharged. 2 reaches the state shown in FIG.
[0056]
Thus, the dimension of the bottom thickness T (see FIG. 10) of the cup portion 94 of the outer cup obtained as the forged product 92 is the first plate provided on the second plate 42 provided on the punch 40 side and the press-fit ring 20 side. It is determined by contact with the plate 44. Therefore, the dimension of the bottom thickness T of the cup portion 94 of the outer cup obtained as the forged product 92 does not vary, and the dimensional accuracy of the bottom thickness T of the cup portion 94 is maintained with high accuracy.
[0057]
In this way, the punch 40 is lowered and reaches the molding end position shown in FIG. 2 from the molding start position shown in FIG. 1, and the forging material is passed through the punch 40, the lower die 28 and the upper die 26. The forging material is plastically flowed along the shape of the cavity 46.
[0058]
After the forging is completed, the punch 40 is raised to the initial position integrally with the elevating part 54 connected to the ram under the drive action of the mechanical press, so that the punch 40, the holder 80 and the guide sleeve 82 are in the first position. It separates from the hole part 32 of the ring body 34, and will be in the standby state of the next process. Then, the forged product 92 (see FIG. 10) is taken out under the displacement action of the knockout pin 48.
[0059]
Next, the operation and effect of the hydraulic control apparatus 10 including the air vent circuit 127 and the relief pressure relief circuit 135 will be described with reference to the flowchart shown in FIG.
[0060]
It is assumed that the pressure chamber 58 is previously filled with pressure oil having a predetermined hydraulic pressure through the supply passage 118 and the passage 64 under the driving action of the first hydraulic pump 132 (step S1).
[0061]
In addition, the air vent valve 131 of the air vent circuit 127 is deenergized so that the valve is opened in advance. Therefore, the air mixed in the pressure oil filled in the pressure chamber 58 is discharged to the tank 110 through the passage 125, the passage 129 and the discharge passage 108 together with a small amount of pressure oil leaking from the pressure chamber 58. As a result, The air in the pressure oil filled in the pressure chamber 58 is surely removed.
[0062]
After such preparatory work is completed, a controller (not shown) energizes the electromagnetic valve to close the air vent valve 131 (step S2).
[0063]
When the air vent valve 131 is closed, the pressure sensor 121 detects the filling pressure of the pressure oil filled in the pressure chamber 58 (see FIG. 12) and derives the detection signal to a controller (not shown). The controller determines whether or not the filling pressure of the pressure oil in the pressure chamber 58 is equal to or higher than a set pressure based on the detection signal (step S3). If the filling pressure is less than the set pressure, the controller drives to a mechanical press (not shown). Deriving a stop signal. As a result, the mechanical press immediately stops its operation, whereby the punch 40 is held in a state stopped at the top dead center (step S4). If the pressure oil filling pressure in the pressure chamber 58 is equal to or higher than the set pressure, the process proceeds to step S5.
[0064]
In step S5, the punch 40 descends under the driving action of the mechanical press, and molding of the forging material starts, whereby the hydraulic pressure of the pressure oil in the pressure chamber 58 increases. In this case, the pressure sensor 121 detects the hydraulic pressure of the pressure oil in the pressure chamber 58 at the initial stage of molding (see FIG. 12), and derives the detection signal to a controller (not shown). The controller determines from the detection signal whether the hydraulic pressure of the pressure oil in the pressure chamber 58 at the initial stage of molding has increased to an initial set hydraulic pressure (step S6), and the hydraulic pressure of the pressure oil in the pressure chamber 58. Is not increased to the initial set oil pressure, an energizing signal is derived to the relief pressure relief valve 133 on the assumption that no forging material is loaded in the cavity 46, and the relief pressure relief valve 133 is turned on. As a result, the relief control pressure of the relief valve 104 is released (step S7).
[0065]
That is, the valve position of the relief pressure relief valve 133 is switched, and the pressure oil stored in the relief chamber of the relief valve 104 is tanked via the passage 137, the relief pressure relief valve 133 and the passage 139 through the discharge passage 108. 110 is discharged. Accordingly, the relief control pressure is rapidly reduced to zero, and the relief valve 104 is opened. When the valve position of the relief pressure release valve 133 is switched, the pilot pressure is supplied to the check valve 122, the check valve 122 is closed, and the internal pressure of the high pressure accumulator is maintained at a predetermined pressure.
[0066]
When the relief valve 104 is opened, the inlet port 106 and the outlet port 112 communicate with each other. Under the driving action of the low pressure accumulator 128, a large volume of pressure oil filled in the pressure chamber 58 is used for the low pressure. Inhaled into the accumulator 128. As a result, the flow resistance when a large volume of pressurized oil filled in the pressure chamber 58 flows out along the discharge passage 108 can be reduced, and the generation of surge pressure (see FIG. 9) can be prevented. it can.
[0067]
In this case, the forging material is not loaded, and the pressure oil supporting load of the piston 60 acts on the contact portion between the first plate 44 and the second plate 42, but the relief valve 104 is in the valve open state. As a result, when the relief pressure of the relief valve 104 becomes zero, the pressure oil supporting load applied to the contact portion between the first plate 44 and the second plate 42 becomes zero. There is no impact or damage. At that time, a controller (not shown) regards that the forging material is abnormally loaded, raises the punch 40 under the drive action of the mechanical press, and stops when the top dead center is reached (step S8).
[0068]
Next, when the hydraulic pressure of the pressure oil in the pressure chamber 58 has increased to the initial set hydraulic pressure in the initial stage, the load sensor 45 determines whether a predetermined forming load is applied to the forging material by the punch 40. (Step S9).
[0069]
In other words, the load sensor 45 detects that the first plate 44 and the second plate 42 have come into contact with each other reliably, and the load sensor 45 derives a detection signal to a controller (not shown). Based on the detection signal, the controller determines whether or not the first plate 44 and the second plate 42 have abutted with a predetermined load or more and the forging material has been forged to a predetermined thickness.
[0070]
For example, as indicated by a solid line in FIG. 13, when the output of the load sensor 45 changes in a mountain shape in response to a change in the hydraulic pressure of the pressure oil in the pressure chamber 58, the controller 42 is abutted with a predetermined load or more, and it is determined that the thickness dimension of the forging material is regulated to the predetermined thickness dimension by the contact of the mold.
[0071]
On the other hand, the forming load on the forging material is higher than the pressure oil support load, and the output of the load sensor 45 corresponding to the hydraulic pressure change of the pressure in the pressure chamber 58 is linear as shown by the broken line in FIG. In the case of flatness, the controller determines that the pressure oil is relieved without the first plate 44 and the second plate 42 contacting each other, and the thickness dimension of the forging material is not regulated by the contact of the mold.
[0072]
In addition, the controller which is not shown in figure can make the thickness dimension with respect to the forging raw material still more accurate by feedback-controlling a relief pressure based on the detection signal output from the said load sensor 45. FIG. That is, the controller derives a relief pressure control signal corresponding to the detection signal output from the load sensor 45 to the pressure control valve 136, and controls the relief pressure corresponding to the abutting load, so that the forging material The thickness can be regulated with high accuracy.
[0073]
When the contact of the mold is not detected by the detection signal output from the load sensor 45, the controller considers that the contact of the mold is abnormal, and outputs a drive stop signal to a mechanical press (not shown). Stops at the top dead center (step S10). When a predetermined molding load is applied, the process proceeds to the next step S11.
[0074]
Next, a forming load is applied to the forging material by the punch 40, and before the punch 40 reaches the bottom dead center, the pressure sensor 121 detects the relief set pressure in the pressure chamber 58 (see FIG. 12). ), A detection signal is derived to a controller (not shown). A controller (not shown) determines whether or not the relief set pressure is within a predetermined range based on the detection signal (step S11).
[0075]
When the relief set pressure is not within the predetermined range, a drive stop signal is output to a mechanical press (not shown), and the punch 40 is raised and then stopped at the top dead center (step S12). When it is determined that the relief set pressure is within the predetermined range, the process proceeds to the next step S13.
[0076]
In the next step S13, the pressure oil in the pressure chamber 58 is relieved under the displacement action of the piston 60 and the punch 40 reaches the bottom dead center, and then rises toward the top dead center. In addition, while the punch 40 reaches the top dead center after reaching the bottom dead center, the pressure chamber 58 is again filled with the pressure oil through the supply passage 118, and the piston 60 is initialized. Then, the solenoid valve is deactivated by a controller (not shown), and the air vent valve 131 is opened (steps S14 to S17).
[0077]
By continuing such a process, forging can be continuously performed on the forging material.
[0078]
In the present embodiment, it is detected that the forging material is not loaded in the cavity 46 at the stage of initial increase in hydraulic pressure, and the pressure oil support load is made zero by switching the valve position of the relief pressure relief valve 133. An overload is prevented from being applied to the mold when the first plate 44 and the second plate 42 come into contact with each other. As a result, in the present embodiment, it is possible to avoid the occurrence of stress in the mold, to prevent the mold from being damaged, and to improve the durability of the mold.
[0079]
Further, in the present embodiment, the fluctuation due to the extension of the frame of the mechanical press (not shown), the connecting rod, etc., which usually causes the fluctuation of the thickness dimension of the forging material, is absorbed as the change in the stroke amount of the piston 60, Moreover, since the material thickness dimension is defined by the contact between the upper mold and the lower mold, it is not affected by the extension of the frame or the like.
[0080]
In this embodiment, the outer cup that constitutes the constant velocity joint is used as a forging material, but the present invention is not limited to this. For example, a stepped component (not shown), a stepped gear, etc. Of course, the present invention can be applied to various forged molded products that require dimensional accuracy in the thickness direction.
[0081]
In addition, in the present embodiment, the buffer mechanism 56 is provided in the lifting part 54 on the displacement side, but the present invention is not limited to this, and the buffer mechanism 56 is provided on the fixed side such as the upper die 26 and the lower die 28. It may be provided.
[0082]
【The invention's effect】
According to the present invention, the following effects can be obtained.
[0083]
That is, when the forging material is not loaded in the cavity, the mold can be prevented from being damaged even if the upper mold and the lower mold come into contact with each other, and the durability of the mold can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a forging die incorporating a hydraulic control apparatus according to an embodiment of the present invention.
FIG. 2 is an operation explanatory view showing a state where the punch is lowered from the forging forming start position shown in FIG. 1 and the forging is finished.
FIG. 3 is a schematic configuration diagram of a hydraulic control apparatus according to an embodiment of the present invention.
4 is a partially enlarged sectional view of the forging die shown in FIG. 1. FIG.
FIG. 5 is an explanatory view showing a manufacturing process of an outer cup constituting a constant velocity joint.
FIG. 6 is an explanatory view showing a manufacturing process of an outer cup constituting a constant velocity joint.
FIG. 7 is an explanatory view showing a manufacturing process of an outer cup constituting a constant velocity joint.
FIG. 8 is an explanatory view showing a manufacturing process of an outer cup constituting a constant velocity joint.
FIG. 9 is an explanatory diagram showing the relationship between the amount of punch displacement and the pressure value of pressure oil.
FIG. 10 is an explanatory view showing the dimension of the bottom thickness of the cup of the outer cup obtained as a forged product.
FIG. 11 is a flowchart illustrating the operation of the hydraulic control apparatus according to the present embodiment.
FIG. 12 is an explanatory diagram showing the relationship between the oil pressure of the pressure oil filled in the pressure chamber and time.
FIG. 13 is an explanatory diagram showing an output of a load sensor corresponding to a change in hydraulic pressure in the pressure chamber when the first plate and the second plate are in contact with each other and not in contact.
[Explanation of symbols]
10 ... Hydraulic controller 11 ... Die for forging
12a to 12d ... guide means 14, 16, 18 ... die holder
20 ... Press-fit ring 26, 28 ... Dice
34, 36 ... Ring body 40 ... Punch
42, 44 ... Plate 45 ... Load sensor
46 ... Cavity 54 ... Elevating part
56 ... Buffer mechanism 58 ... Pressure chamber
60 ... Piston 62 ... Block body
64, 119, 120, 125, 126, 129, 137, 139 ... passage
102 ... Hydraulic power source 104 ... Relief valve
106 ... Inlet port 108 ... Passage for discharge
110 ... Tank 112 ... Outlet port
114 ... relief pressure supply passage 116 ... relief port
118 ... Supply passage 121 ... Pressure sensor
127 ... Air bleeding circuit 131 ... Air bleeding valve
133 ... Relief pressure relief valve 135 ... Relief pressure relief circuit
136 ... Pressure control valve

Claims (13)

A method for controlling a forging die provided with a buffer mechanism for absorbing a surplus displacement amount from when the first die member and the second die member come into contact with each other until reaching the bottom dead center,
A forging material is loaded into a cavity provided in the first die member , and a punch provided in the second die member is displaced so that the punch comes into contact with the forging material and forging is performed on the forging material. front from the start and the first mold member and the second mold member abuts the pressure of the pressure fluid filled in the pressure chamber constituting the buffer mechanism has reached the initial setting pressure in molding the early stages If the pressure fluid does not reach the initial set pressure, the pressure fluid filled in the pressure chamber is forcibly led out to the outside as if the forging material is not loaded. A method for controlling a forging die characterized by the above. The method of claim 1, wherein
The method for controlling a forging die, wherein the pressure fluid filled in the pressure chamber is led out by energizing an electromagnetic valve to release a relief pressure of the relief valve. The method according to claim 1 or 2, wherein
The method for controlling a forging die, wherein the pressure fluid comprises pressure oil. The method according to claim 1 or 2, wherein
Detecting the pressure of the pressure fluid filled in the pressure chamber, and stopping the relative displacement between the first mold member and the second mold member when the pressure fluid is out of a predetermined filling pressure range. A method for controlling a forging die. The method according to any one of claims 1 to 4,
After the punch comes into contact with the forging material and starts forging with respect to the forging material , the abutment load when the first die member and the second die member come into contact is detected by a load sensor, and the load A method for controlling a forging die, wherein it is determined whether or not the forging material has been forged to a predetermined thickness based on a detection signal derived from a sensor . The method according to any one of claims 1 to 5,
When the relief pressure of the pressure fluid in the pressure chamber from when the first die member and the second die member come into contact until reaching the bottom dead center is detected and the relief pressure is outside a predetermined range, A method for controlling a forging die, wherein the relative displacement between the first die member and the second die member is stopped. The method according to any one of claims 1 to 6,
The method for controlling a forging die, wherein the air mixed in the pressure fluid in the pressure chamber is removed to the outside together with the pressure fluid leaking from the pressure chamber. By forcibly displacing the first die member and the second die member and applying pressure to the forging material loaded in the cavity, forging molding for the forging material is started and the bottom dead center is reached. A control device for a forging die for bringing the first die member and the second die member into contact with each other before reaching ,
The first mold member and the second mold member are relatively displaced, and the first mold member and the second mold member are brought into contact with each other by the action of the pressure fluid filled in the pressure chamber, and then the bottom dead center is reached. A buffer mechanism that absorbs the amount of displacement of the surplus until it reaches,
Pressure detecting means for detecting the pressure of the pressure fluid filled in the pressure chamber;
Based on the detection signal output from the pressure detection means, the pressure of the pressure fluid filled in the pressure chamber constituting the buffer mechanism is changed between the first die member and the first die member after the forging forming for the forging material is started. Pressure fluid control for deriving the pressure fluid filled in the pressure chamber to the outside on the assumption that the forging material is not loaded when the initial set pressure at the initial stage of molding before the contact with the mold 2 member has not been reached Means,
A control device for a forging die, comprising: The apparatus of claim 8.
The pressure fluid control means includes a relief valve having an inlet port communicating with the pressure chamber, and an electromagnetic valve connected to the relief port of the relief valve and releasing the relief pressure of the relief valve under a switching action. Forging die control device characterized by the above. The device according to claim 8 or 9,
The forging die control device according to claim 1, wherein the pressure fluid comprises pressure oil. The device according to any one of claims 8 to 10,
The forging metal, wherein the pressure detecting means comprises a pressure sensor, and a load sensor for detecting whether or not the first mold member and the second mold member are in contact with each other is provided separately from the pressure sensor. Mold control device. 12. The device according to any one of claims 8 to 11,
An air vent circuit for removing air mixed in the pressure fluid in the pressure chamber is provided, and under the biasing action of the air vent circuit, the air mixed in the pressure fluid together with the pressure fluid leaking from the pressure chamber A control device for a forging die, which is led out to the outside. The apparatus of claim 9.
A forging die control apparatus, comprising a pressure control valve for controlling the pressure of the pressure fluid supplied to the relief chamber of the relief valve.

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