JP5584881B2 - Spark sintering equipment - Google Patents

Description

  The present invention relates to a discharge sintering apparatus. More specifically, the present invention relates to a discharge sintering apparatus that can perform bonding or sintering with higher thermal efficiency and higher accuracy in a discharge sintering apparatus in which a turntable on which a plurality of workpieces can be placed is provided in a vacuum chamber.

  As a technology related to the invention of the present application, there is an electric pressure sintering apparatus in which a rotary table as described in Patent Document 1 is provided in a vacuum chamber.

  The current-pressure sintering apparatus (1) described in Patent Document 1 is an improvement over the conventional tunnel-type continuous sintering apparatus in which a preheating chamber, a sintering chamber, and a cooling chamber each kept in a vacuum are linearly provided. This is characterized in that the structure of the apparatus is simplified by performing preheating, sintering and cooling steps in one vacuum chamber (2).

More specifically, the sintering mold (80) disposed on the rotary table (5) in the energization pressure sintering apparatus (1) includes a hollow cylindrical mold (81) and a mold (81). It consists of a pair of upper and lower dies (82, 83) that fit into a cylindrical portion, and in the hollow portion formed by the mold (81) and a pair of upper and lower dies (82, 83), copper, nickel as a sintered material, After being filled with powder such as alumina (Al ₂ O ₃ ), it is compressed by the upper and lower pressure electrodes (26, 27) and is electrically sintered.

JP 2002-105507 A

  However, the energizing pressure sintering apparatus described in Patent Document 1 has a problem that the temperature of the vacuum chamber (2) rises due to radiant heat from the mold (81) that has become a high temperature during sintering.

  Further, the radiant heat from the mold causes thermal energy during sintering to be dissipated from the vacuum chamber to the outside, thereby reducing thermal efficiency.

  Further, the heat of the mold that has reached a high temperature is transferred from the sintering mold holding portion (60) to the rotary table by heat conduction, and the rotary table and the shaft (6) of the rotary table are thermally deformed to perform high-precision sintering or bonding. There is also a problem that cannot be done.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a discharge sintering apparatus equipped with a turntable in which a plurality of workpieces can be placed in a vacuum chamber. It is an object of the present invention to provide a discharge sintering apparatus that can perform sintering or bonding with high thermal efficiency and high accuracy.

  The discharge sintering apparatus according to claim 1, as means for solving the above-described problem, includes a vacuum chamber for sealing a workpiece, and pressurizing and bonding the workpiece in the vertical direction in the vacuum chamber. In a discharge sintering apparatus comprising a pair of upper and lower electrodes and a turntable provided at an upper part of a rotating shaft and having a peripheral portion rotating and passing horizontally between the pair of upper and lower electrodes, the pair of upper and lower electrodes are disposed on the periphery of the turntable. A through hole through which one lower electrode of the electrode can freely pass is provided at a predetermined interval in the circumferential direction, and a lower spacer holding portion for holding the conductive lower spacer so as to be movable up and down is provided above the through hole. A workpiece positioning member is detachably provided on the lower spacer held by the lower spacer holding portion, and a heat insulating cover is provided on the turntable to surround and surround the workpiece positioning member. Serial positioned between the upper and lower pair of electrodes said and is characterized in that the workpiece pressure sintering or bonding.

  The electric discharge sintering apparatus according to claim 2 is the electric discharge sintering apparatus according to claim 1, wherein radiant heat from the workpiece is measured outside the vacuum chamber on the workpiece positioning member and the heat insulating cover. It is characterized by providing a measurement peephole that passes through the instrument.

  According to a third aspect of the present invention, in the electric discharge sintering apparatus according to the second aspect, the peephole for measurement is a long hole extending in the vertical direction.

  The electric discharge sintering apparatus according to claim 4 is the electric discharge sintering apparatus according to claim 3, wherein the heat insulating cover is provided so as to be divided in two in the vertical direction, and the vertical direction from above to the workpiece positioning member. The slit is provided.

The discharge sintering apparatus according to claim 5 is the discharge sintering apparatus according to claim 1, wherein a cooling water supply path and a cooling water drainage path communicating from below to the upper end of the rotating shaft are provided, and the cooling water is provided. It flows in from the lower part of a supply path, and flows out from the lower part of the said cooling water drainage path via the cooling water circulation path provided in the circumference | surroundings of the said through-hole.

  According to the present invention, since the heat insulation cover for keeping the work material is provided around the work material holder, the radiant heat of the heat insulation cover whose temperature is increased by the radiant heat from the work material is returned to the work material. Therefore, energy and heating time required for heating the workpiece can be shortened.

  In addition, a cylindrical workpiece positioning member that fills workpieces is detachably fitted and attached to the lower spacer provided on the turntable, so it can be joined with high accuracy when joining multiple workpieces. can do. In addition, since the workpiece positioning member is provided with a longitudinal slit, the workpiece positioning member is not damaged even if the workpiece is thermally expanded.

  Moreover, by providing the heat insulation cover around the workpiece holder, the radiant heat to the vacuum chamber is reduced, and the temperature rise of the vacuum chamber can be suppressed. This increases the cooling efficiency of the vacuum chamber. In addition, a measurement peephole is provided in the workpiece positioning member and the heat insulation cover to detect the radiant heat from the workpiece from the outside of the vacuum chamber, so that the temperature of the workpiece can be measured from the outside of the vacuum chamber. can do.

  Since the heat insulating cover arranged around the workpiece positioning member is provided so as to be divided into two in the vertical direction, it can be easily installed on the turntable in a narrow vacuum chamber.

  In addition, since the turntable cooling water passage that flows into the turntable from the lower part of the rotating shaft of the turntable and flows out from the lower part of the rotating shaft via the cooling water circulation passage provided in the turntable is provided, Both shafts can be efficiently cooled simultaneously, and thermal distortion of the turntable during sintering or joining can be suppressed.

The front view of the electric discharge sintering apparatus which concerns on this invention. The figure which fractured | ruptured and showed in the side view of FIG. AA sectional drawing in FIG. BB sectional drawing in FIG. CC sectional drawing in FIG. DD sectional drawing in FIG. FIG. 7 is a top view of FIG. 6.

  Embodiments of the present invention will be described below with reference to the drawings.

  Embodiments of the present invention will be described with reference to the drawings. 1 and 2 are a front view and a side view of a discharge sintering apparatus 1 according to the present invention, and FIG. 2 is a schematic explanatory view of a vacuum chamber 3 for performing sintering or joining.

  As shown in FIGS. 1 and 2, the electric discharge sintering apparatus 1 includes an electric discharge sintering apparatus body 5 including the vacuum chamber 3 and a power supply apparatus 7 for electric discharge sintering. The vacuum chamber 3 is integrally fixed to the electric discharge sintering apparatus main body 5 by appropriate coupling means such as welding.

  Referring also to FIG. 3, the vacuum chamber 3 is a cylindrical hermetic container extending horizontally, and the side wall of the vacuum chamber 3 has a double structure having an inner wall 9 and an outer wall 11. The cooling water 13 is circulated between the inner wall 9 and the outer wall 11 so as to be cooled to about room temperature.

  The vacuum chamber 3 is fixed below the vacuum chamber 3 to a vacuum chamber support plate 14 provided integrally with the main body 5 of the spark sintering apparatus, for example, by welding.

  An upper electrode guide 15 penetrating in the vertical direction into the vacuum chamber 3 is provided above the vacuum chamber 3, and an upper electrode 17 is fitted to the upper electrode guide 15 so as to be movable up and down. The upper electrode guide 15 and the upper electrode 17 are airtightly provided by a seal member. An upper spacer 18 made of graphite is mounted on the lower surface of the upper electrode 15 by appropriate means.

  A cylinder support member 21 fixed to a plurality of support rods 19 erected from the vacuum chamber support plate 14 is provided above the vacuum chamber 3. The cylinder support member 21 is provided with an upper hydraulic cylinder 23 having a piston rod that can be protruded and retracted downward. The upper end of the upper electrode 17 is connected to the piston rod of the upper hydraulic cylinder 23. .

  In the above configuration, the upper electrode 17 can be moved up and down to an appropriate position in the vacuum chamber 3 by operating the upper hydraulic cylinder 23.

  On the other hand, a lower electrode 25 facing the upper electrode 17 is provided below the upper electrode 17 so as to be moved up and down by a lower hydraulic cylinder 27. Similar to the upper electrode 17, the lower electrode 25 is provided so as to be movable up and down and airtight in a lower electrode guide (not shown) penetrating vertically into the vacuum chamber 3.

  The lower hydraulic cylinder 27 is provided on a cylinder support member 31 fixed to a support rod 29 extending downward from the vacuum chamber support plate 14.

  In the above configuration, by operating the lower hydraulic cylinder 27, the lower electrode 25 can be moved up and down to an appropriate position in the vacuum chamber 3.

  2 and 3 together, a bearing support block 33 is integrally provided at the lower portion of the vacuum chamber 3. A bearing housing 39 that supports a rotating shaft 37 of a circular turntable 35 that rotates horizontally inside the vacuum chamber 3 is attached to the bearing support block 33.

  The bearing housing 39 has a through hole 41 having a diameter slightly larger than that of the rotating shaft 37, and a stepped hole 43 having a diameter larger than that of the through hole 41 is provided on the upper portion of the through hole 41. A hooked bush 45u with which the rotary shaft 37 is rotatably engaged is fitted in the stepped hole 43.

  The upper portion of the rotating shaft 37 is formed to have a slightly larger diameter than the engaging portion with the flanged bush 45u. The turntable 35 is attached to a flange 37 f at the upper end of the rotating shaft 37 with a plurality of bolts 32. A positioning key 40 is engaged between the turntable 35 and the flange 37f, and relative rotation between the rotary shaft 37 and the turntable 35 is restricted.

  A thrust bearing 47u that receives a downward thrust load of the rotary shaft 37 is provided on the bushed bush 45u, and the lower surface of the large-diameter portion of the rotary shaft 37 is in contact with the thrust bearing 47u. Match.

  The bushed bushing 45u and the thrust bearing 47u are fixed to the upper portion of the bearing housing 39 by an annular bearing retainer 49. The bearing holder 49 and the rotary shaft 37 are airtightly provided by a seal member.

  Like the upper part of the bearing housing 39, a bushed bushing 45 l and a thrust bearing 47 l that engage with the rotary shaft 37 are fixed to the bearing support block 33 by a presser nut 51. It is.

  In the above configuration, the rotary shaft 37 is rotatably supported by the hooked bush 45 (u, l), and the downward thrust load applied to the rotary shaft 37 is transmitted through the thrust bearing 47u and the hooked bush 45u. And supported by the bearing support block 33.

  As shown in FIG. 3, the rotating shaft 37 extends downward from the bearing support block 33, and a lower end portion of the rotating shaft 37 is connected to a geared motor via a known coupling 53 and a torque limiter 55. It is connected to an output shaft 58 of 57 through an appropriate conduction mechanism. The geared motor 57 is attached to the cylinder support member 31 at an appropriate position.

  A cover 59 through which the rotary shaft 37 can be inserted is provided at the lower part of the bearing housing 39. On the lower surface of the cover 59, an annular cooling water drain port 61 and a cooling water supply port 63 into which the rotary shaft 37 is rotatably fitted are attached to the cover 59 via a fixing plate 65. .

  The turntable 35 has a structure in which an annular heat insulating cover base 38 is integrally joined on a turntable base 36. Coaxial through holes 67a and 67b through which the lower electrode 25 can pass are provided at predetermined intervals in the circumferential direction on the turntable base 36 and the heat insulating cover base 38 at the periphery of the turntable 35, respectively. is there. In the embodiment, the circumferences are arranged at equal intervals, that is, at intervals of 90 degrees.

  An engagement hole 95 for holding the lower spacer 93 so as to be movable up and down is provided as a lower spacer holding portion in the upper portion of the through hole 67b provided in the heat insulating cover base 38 of the turntable 35. The lower spacer 93 is disposed between the lower electrode 25 and the workpiece W, and the material needs to have conductivity and heat resistance. In the examples, graphite is used, but it is not limited to graphite.

  When a plurality of workpieces W are placed on the lower spacer 93 for joining, a cylindrical workpiece positioning member 97 is used to make the joining position accurate. The workpiece positioning member 97 has a cylindrical shape that engages with the contour of the workpiece W. By inserting a plurality of workpieces W, for example, a plurality of workpieces as shown in FIG. W1, W2 and W3 can be aligned coaxially. Further, in the case of sintering, an upper punch is inserted into the W1 portion of the workpiece positioning member 97, a mold portion containing powder to be sintered is inserted into the W2 portion, and a lower punch is inserted into the W3 portion. Further, two sets of W (1, 2, 3) set can be placed in the workpiece positioning member 97 and simultaneously sintered in series.

  The lower spacer 93 is provided with a positioning hole 98 that engages with the bottom of the workpiece positioning member 97 with the workpiece W inserted therein. The positioning hole 98 is provided coaxially with the upper and lower electrodes (17, 25).

  Referring to FIGS. 6 and 7, the workpiece positioning member 97 is provided with a vertical slit 99 from the top to the bottom and a measurement peep hole 101 made of a long hole. Note that high-heat-resistant graphite is suitable for the material for the workpiece positioning member 97. By providing the slit, the workpiece positioning member 97 is not broken even if the workpiece W expands during the joining process.

  A heat insulating cover tray 71 on which a cylindrical heat insulating cover 69 (a, b) that can be divided into two semicircles in the longitudinal direction surrounding the workpiece positioning member 97 is provided. 73 is fixed. Further, the heat insulation cover 69 is provided with a measurement peep hole 102 made of the same elongated hole at the same height as the measurement peep hole 101 of the workpiece positioning member 97. Although both the heat insulating cover 69 and the heat insulating cover tray 71 are made of graphite, which is a high heat resistant material, ceramics may be used.

  In order to electrically insulate between the turntable 35 and the rotating shaft 37, an insulating sheet 79 is inserted between the turntable base 36 and the flange 37 f of the rotating shaft 37, and the turntable 35 is connected to the rotating shaft 37. An insulator is also inserted between the bolt 32 and the turntable 35 that are fixed to the base plate.

  In order to electrically insulate between the heat insulation cover 69 and the turntable 35, a ceramic washer 75 is inserted between the heat insulation cover 69 and the bolt 73 and between the heat insulation cover tray 71 and the heat insulation cover base 38. Between the bolt 73 and the heat insulating cover tray 71, a ceramic bush 77 is inserted.

  The workpiece positioning member 97 is in contact with the workpiece W (1, 2, 3), but since the contact pressure is weak, the electrical resistance between the two is high. Further, although the workpiece positioning member 97 is in contact with the lower spacer 93, since it does not receive pressure from the electrode 17, its contact resistance is also large. Therefore, the current flowing from the electrode 17 flows through the workpiece W (1, 2, 3) to the lower spacer 93, and the current passing through the workpiece positioning member 97 is negligibly small.

  The electrical insulation means as described above can prevent a current from flowing to the geared motor 57 via the rotating shaft 37 even if the heat retaining cover 69 contacts the upper electrode 17.

The heat retaining effect of the graphite heat retaining cover 69 will be described. All objects emit heat energy from their surface, and the amount of heat increases rapidly as the temperature of the object increases. The amount of heat radiated is given by the following equation called the Stefan-Boltzmann law.
(Equation 1)
Q = 4.88 · ε · (T / 100) ⁴ (1)
Here, Q: the amount of heat radiated from the unit area of the solid surface (Kcal), T: absolute temperature, ε: the correction coefficient due to the type and surface state of the object, the black body is the highest and is almost 1.

  As can be seen from the equation (1), the energy of the radiant heat is released in proportion to the fourth power of the temperature. Giving this amount of heat to the vacuum chamber 3 and throwing it out of the system is a waste of energy. The thermal energy radiated from the workpiece W is first absorbed by the workpiece positioning member 97. The workpiece positioning member 97 that has reached a high temperature radiates heat to the inner workpiece W and the outer heat retaining cover 69 (a, b). When the temperature of the heat insulating cover 69 (a, b) rises, the heat insulating cover 69 (a, b) emits radiant heat to the inside and the outside.

In the embodiment of the present invention, a graphite workpiece positioning member 97 and a heat retaining cover 69 (a, b) having the highest radiation efficiency are used. During actual processing, when the temperature of the workpiece W was 1800 ° C, the temperature of the heat insulating cover 69 (a, b) was about 500 ° C. That is, since the amount of radiant heat is proportional to the fourth power of the absolute temperature T, it becomes (T / 3.6) ⁴ , which is about 1 / 170th smaller.

  Next, the cooling means for the turntable 35 will be described.

  The rotating shaft 37 is provided with a cooling water supply path 81 (a, b) and a cooling water drainage path 83 (a, b) communicating from the lower side to the upper end. The cooling water supply path 81 (a, b) is provided at its lower end with a water receiving port 84 opened to the side of the rotary shaft 37, and at the lower end of the cooling water drainage path 83 (a, b), the rotary shaft 37. A drain port 86 opened to the side is provided.

  A cooling water circulation path 68 communicating with the cooling water supply path 81 (a, b) and the cooling water drainage path 83 (a, b) is provided around the through hole 67 b of the heat insulating cover base 38. The cooling water supply port 63 and the cooling water drain port 61 are arranged in accordance with the positions of the water receiving opening and the drain opening. Further, the positions of the water receiving opening and the drain opening are provided in positions that are separated in the vertical direction so as not to communicate with each other and in a direction orthogonal to each other.

  The inner periphery of the cooling water supply port 63 and the cooling water drain port 61 is provided with an annular groove that opens to the rotating shaft 37, and the cooling water supplied from a pump (not shown) Even if 37 rotates, it is always supplied to the cooling water supply path 81 (a, b). Similarly, drainage from the cooling water drainage channel 83 (a, b) can always be discharged even if the rotary shaft 37 rotates.

  The cover 59 is restricted from rotating relative to the rotary shaft 37 by a key 85 provided on the bearing support block 33. Therefore, even if the rotating shaft 37 rotates, the cooling water supply port 63, the cooling water drain port 61, and the fixing plate 65 fixed to the cover 59 do not move.

  As a means for detecting the rotational position of the turntable 35, for example, a disk-shaped detected body 87 having a gear-shaped groove on the outer periphery is provided on the rotating shaft 37, and the rotation angle of the detected body 87 is detected. A non-contact position detection sensor 89 is provided on the bracket 91 fixed to the fixed plate 65.

  In the above configuration, the turntable 35 can be rotationally positioned at a desired position by appropriately rotating the geared motor 57 under the control of a control device (not shown). In addition, the torque limiter 55 can prevent overload on the geared motor 57.

  Referring to FIG. 4, the left side surface (upper side in FIG. 4) of the vacuum chamber 3 is provided with the presence / absence of the workpiece W and a viewing window 103 for temperature measurement. In addition, on the right side surface (lower side in FIG. 4) of the vacuum chamber 3, a photodetector 105 for detecting the presence or absence of the workpiece W is provided at a position facing the viewing window 103.

  A projector 107 is attached to the viewing window 103. The projector 107 is mounted at a position where the projected light beam 109 passes through the axial center O (processing center) of the upper electrode 17 and the lower electrode 25, and the workpiece positioning member 97 on the turntable 35 and the heat retaining member. The position is set so as to pass through the measurement peep holes (101, 102) provided in the cover 69a.

  Therefore, the presence or absence of the workpiece W is determined by whether or not the light beam 109 projected from the light detector 105 is detected by the light detector 105. Further, if the light thermometer 111 is installed instead of the projector 105, the temperature of the workpiece W can be measured.

  Further, a viewing window 115 for checking with the naked eye is provided on the door 113 on the front side (left side in FIG. 4) of the vacuum chamber 3 at a position where the heat insulation cover 69a at the processing center can be seen. Thereby, the presence or absence of the workpiece W can be confirmed with the naked eye.

  Next, a case where a plurality of workpieces W1, W2, and W3 are joined will be described with reference to FIGS.

  The front door 113 provided on the front side (left side in FIG. 2) of the vacuum chamber 3 is opened, a lower spacer 93 is set on the turntable 35, and a workpiece W (in this embodiment, joined to the lower spacer 93). A workpiece positioning member 97 loaded with three workpieces (W1 to W3) is mounted. Next, the heat insulating cover 69 (a, b) is set around the workpiece positioning member 97.

  Next, the front door 113 of the vacuum chamber 3 is closed, and the air in the vacuum chamber 3 is exhausted to a set vacuum level.

  In a state where the upper electrode 17 is at the upper limit position above the workpiece W and the lower electrode 25 is at the lower limit position below R from the turntable 35, the turntable 35 is rotationally driven to process the set workpiece W Position to position.

  Next, the lower electrode 25 is raised to raise the lower spacer 93 to a machining position separated from the turntable 35, and the upper electrode 17 is lowered to bring the workpiece W to the lower electrode 25 with an appropriate pressure. In the sandwiched state, the power supply device 7 is activated to start the joining process.

  During the joining process described above, the turntable 35 and the rotary shaft 37 are cooled by circulating cooling water from a cooling water supply means (not shown), so that the turntable 35 is not thermally deformed.

  When the joining process is completed, the upper electrode 17 is raised, the lower electrode 25 is lowered, the turntable 35 is sequentially rotated, and the next joining process is performed in the above-described process. The product for which the joining process has been completed is taken out after the front door 113 is opened after cooling.

DESCRIPTION OF SYMBOLS 1 Electric discharge sintering apparatus 3 Vacuum chamber 5 Electric discharge sintering apparatus main body 7 Power supply apparatus 9 Inner wall 11 Outer wall 13 Cooling water 14 Vacuum chamber support plate 15 Upper electrode guide 17 Upper electrode 18 Upper spacer 19 Support rod 21 Cylinder support member 23 Upper hydraulic cylinder 25 Lower electrode 27 Lower hydraulic cylinder 29 Support rod 31 Cylinder support member 32, 73 Bolt 33 Bearing support block 35 Turntable 36 Turntable base 37 Rotating shaft 37f Flange 38 Thermal insulation cover base 39 Bearing housing 40 Positioning key 41 Through hole 43 Stage With hole 45 (u, l) With bush 47 (u, l) Thrust bearing 49 Bearing holder 51 Holding nut 53 Coupling 55 Torque limiter 57 Geared motor 58 Output shaft 59 Cover 61 Cooling Water drainage port 63 Cooling water supply port 65 Fixed plate 67 (a, b) Through hole 68 Cooling water circulation path 69 (a, b) Thermal insulation cover 71 Thermal insulation cover tray 75 Washer 77 Bush 79 Insulation sheet 81 (a, b) Cooling water Supply path 83 (a, b) Cooling water drainage path 84 Receiving port 85 Key 86 Drainage port 87 Target object 89 Position detection sensor 91 Bracket 93 Lower spacer 95 Engagement hole 97 Workpiece positioning member 98 Positioning hole 99 Slit 101, 102 Measurement Peephole 103, 115 Peeping Window 105 Photodetector 107 Projector 109 Beam 111 Photothermometer 113 Door W Workpiece

Claims (5)

  A vacuum chamber that seals the workpiece, a pair of upper and lower electrodes that pressurize and sinter or join the workpiece in the vertical direction in the vacuum chamber, and a pair of upper and lower electrodes provided on an upper portion of the rotation shaft. In a spark sintering apparatus comprising a turntable that rotates and passes horizontally between electrodes, a through hole through which one lower electrode of the pair of upper and lower electrodes can pass is provided in the circumferential direction at a predetermined interval in the periphery of the turntable. In addition, a lower spacer holding part is provided above the through hole so that the conductive lower spacer can be moved up and down, and the workpiece positioning member can be attached to and detached from the lower spacer held by the lower spacer holding part. And a heat insulating cover that separates and surrounds the workpiece positioning member on the turntable, and pressurizes and sinters the workpiece positioned between the pair of upper and lower electrodes. Discharge sintering apparatus characterized by bonding.   2. The discharge firing according to claim 1, wherein a measurement peephole is provided in the workpiece positioning member and the heat insulating cover to allow radiant heat from the workpiece to pass to a measuring instrument outside the vacuum chamber. Bonding device.   The discharge sintering apparatus according to claim 2, wherein the peephole for measurement is a long hole extending in the vertical direction.   4. The electric discharge sintering apparatus according to claim 3, wherein the heat insulating cover is provided so as to be split into two in the vertical direction, and a vertical slit is provided from above to the workpiece positioning member. A cooling water supply path and a cooling water drainage path communicating from below to the upper end of the rotating shaft are provided, and the cooling water supply path flows from the lower part of the cooling water supply path and passes through the cooling water circulation path provided around the through hole. The discharge sintering apparatus according to claim 1, wherein the discharge sintering apparatus flows out from a lower part of the cooling water drainage channel.

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