JP2017061008A - Manufacturing method of molded body, manufacturing method of oxygen sensor, and manufacturing method of spark plug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity of a molded body.SOLUTION: In a manufacturing method of a molded body, each of grindstones 12, 13 comprises: tip end grinding parts 71, 81 which grind a portion of a workpiece corresponding to a tip end of the molded body; and side face grinding parts 72, 82 which grind a portion of the workpiece corresponding to a side face of the molded body. In the manufacturing method of the molded body, tip end griding faces 71a, 81a of the tip end griding parts 71, 81 in contact with the workpiece are formed to protrude from end parts 72b, 82b of the side face griding faces 72a, 82a of the side face grinding parts 72, 82 in contact with the workpiece. The manufacturing method of the molded body includes a slanting-moving step. The slanting-moving step is a step of moving the grindstones 12, 13 from a state that the grindstones 12, 13 do not contact with the workpiece to the workpiece along a slanting-moving direction that is slanting against a rotation axis RA so that the grindstones 12, 13 contact with the workpiece to grind the workpiece by the grindstones 12, 13.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a method for manufacturing a molded body ground with a grindstone, and an oxygen sensor and a spark plug manufacturing method including the molded body.

  2. Description of the Related Art Conventionally, there is known a grinding apparatus that manufactures a molded body by processing a workpiece by grinding the workpiece with a grindstone while rotating the workpiece about a preset rotation axis (for example, Patent Document 1). reference).

JP 2010-198951 A

  When forming the sensing element of the oxygen sensor and the insulator of the spark plug with a grinding device, it is necessary to move the grindstone at a low speed in order to prevent the workpiece from being broken or cracked. There is a problem that the processing time becomes long.

  This invention is made | formed in view of such a problem, and it aims at improving the productivity of a molded object.

  The present invention made to achieve the above object provides a method for producing a molded body formed by grinding a workpiece to be processed, which is a member to be processed, with a grindstone while rotating around a preset rotation axis. It is.

  Moreover, in the manufacturing method of the molded object of this invention, a grindstone grinds the front-end grinding part which grinds the part corresponding to the front-end | tip of a molded object in a workpiece, and the part corresponding to the side surface of a molded object in a workpiece. A tip grinding surface that is a surface that contacts the workpiece in the tip grinding portion and protrudes from an end of the side grinding surface that is a surface that contacts the workpiece in the side grinding portion. Has been.

  And the manufacturing method of the molded object of this invention is equipped with an oblique movement grinding process. In the oblique movement grinding process, the grindstone is moved by moving the grindstone so as to approach the workpiece along an oblique movement direction oblique to the rotation axis from a state where the grindstone is not in contact with the workpiece. A workpiece is brought into contact with the workpiece and the workpiece is ground with a grindstone.

  In the method of manufacturing a molded body of the present invention configured as described above, the distance between the grindstone and the workpiece to be necessary for preventing the grindstone from coming into contact with the workpiece is perpendicular to the rotation axis. By moving the grindstone along the direction, the grindstone can be shortened compared to the case where the grindstone and the workpiece are brought into contact with each other. For this reason, the manufacturing method of the molded object of this invention can shorten the time required in order to move a grindstone, and can improve the productivity of a molded object.

  Further, in the method for producing a molded body of the present invention, the grindstone is a portion in which the end portion of the grindstone tip grinding surface that is not connected to the end portion of the side grinding surface corresponds to the tip of the molded body in the workpiece. It may be formed so as to coincide with the rotation axis or to protrude beyond the rotation axis when grinding. Thus, when the tip grinding surface coincides with the rotation axis or is formed so as to protrude beyond the rotation axis, the occurrence of a situation in which the portion corresponding to the tip of the molded body in the workpiece is not ground is avoided. be able to. Furthermore, the longer the tip grinding surface protrudes beyond the rotation axis, the more the grinding stone is covered when the grinding wheel is brought into contact with the workpiece by moving the grinding wheel along a direction perpendicular to the rotation axis. The distance between the grindstone and the workpiece to be processed so as not to come into contact with the workpiece is increased. For this reason, the manufacturing method of the molded object of this invention is suitable when the front-end grinding surface is formed so that it may protrude beyond a rotating shaft.

  Further, in the method for producing a molded body according to the present invention, when the grindstone includes a roughing grindstone and a finishing grindstone, the oblique movement grinding step includes at least one of the rough grinding grinding step and the finish grinding step. It may be included. The roughing grindstone is a grindstone that grinds a workpiece to have a preset roughing shape. The finishing grindstone is a grindstone that grinds a workpiece to have a preset finish shape. The rough grinding step is a step of grinding a workpiece by moving the roughing grindstone in the oblique movement direction. The finish grinding step is a step of grinding the workpiece by moving the finish grindstone in the oblique movement direction.

The method for producing a molded body of the present invention configured as described above can improve the productivity of the molded body when grinding a workpiece using both a roughing grindstone and a finishing grindstone.
In addition, the oxygen sensor manufacturing method for manufacturing a molded body to be a detection element of the oxygen sensor by the manufacturing method of the present invention has the same effect as the manufacturing method of the molded body of the present invention. Can be improved.

  In addition, since the spark plug manufacturing method for manufacturing a molded body to be an insulator of the spark plug by the manufacturing method of the present invention has the same effects as the manufacturing method of the molded body of the present invention, the productivity of the spark plug is increased. Can be improved.

2 is a cross-sectional view showing a configuration of an oxygen sensor 101. FIG. FIG. 3 is a plan view showing the periphery of a turntable 11 of the grinding device 1. 1 is a block diagram showing a schematic configuration of a grinding apparatus 1. FIG. It is a flowchart which shows a grinding process. It is a figure which shows the movement pattern of a grindstone, and the diagonal movement of a grindstone. It is a front view which shows the unground workpiece | work WK1, the rough-cut workpiece | work WK2, and the finishing workpiece | work WK3 of a detection element. It is a front view which shows the shape of the grindstones 12 and 13 of 1st Embodiment. It is a figure which shows the distance in the case of moving the grindstones 12 and 13 along the orthogonal | vertical direction and the diagonal movement direction with respect to the rotating shaft RA. FIG. 2 is a front view showing a spark plug 201 with a part thereof broken. It is a front view which shows the rough cutting workpiece WK11 and the finishing workpiece WK12 of an insulator.

(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings.
An oxygen sensor 101 according to an embodiment to which the present invention is applied includes a detection element 102, a ceramic heater 103, and a casing 104, as shown in FIG. In FIG. 1, the oxygen sensor 101 is shown such that the front end side is the lower side and the rear end side is the upper side.

The detection element 102 is formed in a bottomed cylindrical shape that extends in the axial direction (vertical direction in FIG. 1) and has a closed end by a solid electrolyte body mainly composed of ZrO ₂ . The ceramic heater 103 is formed in a rod shape and is disposed in the detection element 102 to heat the detection element 102. The casing 104 is a member for housing the internal structure of the oxygen sensor 101 and fixing the oxygen sensor 101 to an attachment portion such as an exhaust pipe.

  The casing 104 holds the detection element 102 and extends the detection part 125 at the front end thereof into the exhaust pipe or the like, and extends to the upper part of the metal shell 105 so that the reference gas is between the detection element 102 and the casing 104. And an outer cylinder 106 forming a space.

  The metal shell 105 has a cylindrical main body. The metal shell 105 includes a support member 151 that supports the detection element 102 from below, a filling member 152 made of talc powder that fills the upper portion of the support member 151, a sleeve 153 that presses the filling member 152 from above, and the like. To house.

  In other words, a step portion 154 that protrudes inward is provided on the inner periphery on the lower end side of the metal shell 105, and the support member 151 is supported by the step portion 154 via the packing 155, thereby detecting the detection element. 102 is supported from below. A filling member 152 is disposed between the inner peripheral surface of the metal shell 105 on the upper side of the support member 151 and the outer peripheral surface of the detection element 102, and a cylindrical sleeve 153 and a packing 156 are sequentially placed on the upper side of the filling member 152. The upper end portion of the metal shell 105 is crimped inward (downward) while being inserted coaxially. Thereby, the filling member 152 is pressurized and filled, and the detection element 102 is firmly fixed to the metal shell 105.

  In addition, on the outer periphery on the lower end side of the metal shell 105, metal double protectors 157 and 158 having a plurality of holes and covering the protruding portion of the detection element 102 are attached by welding.

The outer cylinder 106 is attached to the metal shell 105 by being welded with the upper portion of the metal shell 105 fitted in the lower end opening thereof.
An insulating separator 107 formed in a cylindrical shape with ceramic is inserted in the vicinity of the upper end opening of the outer cylinder 106.

  The separator 107 has a flange portion 171 protruding outward in the radial direction on the outer peripheral surface near the center in the axial direction. The separator 107 is held inside the outer cylinder 106 via a metal cylindrical holding member 108 that is engaged with the flange portion 171.

  The separator 107 also includes a plurality of insertion holes 174 that penetrate from the rear end surface 172 toward the front end surface 173, and a recess 175 formed in the front end surface 173 so as to accommodate the rear end portion 131 of the ceramic heater 103. . The separator 107 includes a terminal fitting 109 extending from the outer electrode 126 disposed on the outer peripheral surface of the detection element 102 to the tip of the lead wire 121, and an inner electrode 127 disposed on the inner peripheral surface of the detection element 102. The terminal fitting 110 extending to the tip is accommodated in different insertion holes 174 to maintain the insulation between the terminal fitting 109 and the terminal fitting 110 and the insulation between the terminal fitting 109, 110 and the outer tube 106. Yes.

The upper opening of the outer cylinder 106 is closed by a grommet 111 made of fluorine resin, and lead wires 121 and 122 are disposed through the grommet 111.
Next, a method for forming the detection element 102 will be described.

As shown in FIG. 2, the grinding device 1 of the embodiment to which the present invention is applied includes a turntable 11, grindstones 12 and 13, and presser rollers 14 and 15.
The turntable 11 is a member formed in a circular plate shape. The turntable 11 is attached so as to be rotatable around a central axis perpendicular to the circular surface (see the rotation directions RD1 and RD2).

  The turntable 11 includes a plurality (six in this embodiment) of support pins 25 for supporting the workpiece. The support pins 25 are members that protrude from the surface of the turntable 11, and are arranged at regular intervals (every 60 ° in the present embodiment) along the circumferential direction at the outer peripheral end of the surface of the turntable 11. The workpiece is rotated about the support pin 25 as the rotation axis RA (refer to the rotation axis RA in FIGS. 7A and 7B) by inserting the support pin 25 into the recess formed in the work. It is supported by support pins 25 as possible.

  The grindstone 12 grinds a workpiece formed in a cylindrical shape by a solid electrolyte body (see the unground workpiece WK1 in FIG. 6) into a preset detection element rough shape (see the rough workpiece WK2 in FIG. 6). Is for. The grindstone 12 is a columnar member whose circumferential surface is shaped into a shape corresponding to the detecting element rough shape. As shown in FIG. 7A, the grindstone 12 includes a tip grinding portion 71 that grinds a portion corresponding to the tip of the detection element 102 and a side grinding portion 72 that grinds a portion corresponding to the side surface of the detection element 102. Prepare. The tip grinding part 71 and the side grinding part 72 are respectively provided with a tip grinding surface 71a and a side grinding surface 72a in contact with the workpiece. The tip grinding surface 71a is formed so as to protrude from the end portion 72b of the side grinding surface 72a. Furthermore, the tip grinding surface 71a is formed so as to protrude beyond the rotation axis RA when a portion corresponding to the tip of the detection element 102 is ground.

  As shown in FIG. 2, the grindstone 12 is attached so as to be rotatable about its cylindrical axis (see the rotation direction RD3). Moreover, the grindstone 12 is attached so that it can approach the outer periphery of the turntable 11 along the radial direction of the turntable 11, or can move away from the outer periphery of the turntable 11 (refer to the moving direction MD1). Hereinafter, the movement approaching the outer periphery of the turntable 11 is referred to as forward movement, and the movement away from the outer periphery of the turntable 11 is referred to as backward movement.

  The grindstone 13 is used to grind the workpiece ground to the detection element rough shape (see the rough workpiece WK2 in FIG. 6) into a preset detection element finish shape (see the finished workpiece WK3 in FIG. 6). is there. The grindstone 13 is a cylindrical member whose circumferential surface is shaped into a shape corresponding to the detection element finish shape. As shown in FIG. 7B, the grindstone 13 includes a tip grinding portion 81 that grinds a portion corresponding to the tip of the detection element 102 and a side grinding portion 82 that grinds a portion corresponding to the side surface of the detection element 102. Prepare. The tip grinding part 81 and the side grinding part 82 are respectively provided with a tip grinding surface 81a and a side grinding surface 82a in contact with the workpiece. The tip grinding surface 81a is formed so as to protrude from the end portion 82b of the side grinding surface 82a. Furthermore, the tip grinding surface 81a is formed so as to protrude beyond the rotation axis RA when a portion corresponding to the tip of the detection element 102 is ground.

  As shown in FIG. 2, the grindstone 13 is attached so as to be rotatable about its cylindrical axis (see the rotation direction RD4). Further, the grindstone 13 is attached at a position different from the grindstone 12 so as to approach the outer periphery of the turntable 11 or move away from the outer periphery of the turntable 11 along the radial direction of the turntable 11 ( See moving direction MD2).

  The presser roller 14 is a cylindrical member, and is disposed above the turntable 11 so as to face the grindstone 12. The presser roller 14 is attached so as to be rotatable about its cylindrical axis (see the rotation direction RD5). The presser roller 14 is attached so as to be able to approach the grindstone 12 or move away from the grindstone 12 along the radial direction of the turntable 11 (see the moving direction MD3).

  The presser roller 15 is a columnar member, and is disposed above the turntable 11 so as to face the grindstone 13. The presser roller 15 is attached so as to be rotatable about its cylindrical axis (see the rotation direction RD6). The presser roller 15 is attached so as to be able to approach the grindstone 13 or move away from the grindstone 13 along the radial direction of the turntable 11 (see the moving direction MD4).

  As shown in FIG. 3, the grinding device 1 further includes a supply take-out unit 16, a drive unit 17, a drive mechanism 18, a detection device 19, a display device 20, an input device 21, and a control device 22. Prepare.

The supply / extraction unit 16 supplies the work received from the process equipment (hereinafter referred to as pre-process equipment) before the grinding apparatus 1 to the turntable 11 and the work after the grinding by the grinding apparatus 1 is performed. Is taken out from the turntable 11. The supply / withdrawing unit 16 supports an unground workpiece (see the unground workpiece WK1 in FIG. 6) formed in a bottomed cylindrical shape whose tip is closed by a solid electrolyte body mainly composed of ZrO ₂ . The workpiece is supplied to the turntable 11 by inserting it into

The drive unit 17 includes motors 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, and 42.
The motor 31 is a driving source that supplies a driving force for rotating the turntable 11. The motor 32 is a driving source that supplies a driving force for rotating the grindstone 12. The motor 33 is a driving source that supplies a driving force for moving the grindstone 12 back and forth with respect to the turntable 11. The motor 34 is a driving source that supplies a driving force for moving the grindstone 12 up and down with respect to the turntable 11.

  The motor 35 is a driving source that supplies a driving force for rotating the grindstone 13. The motor 36 is a driving source that supplies a driving force for moving the grindstone 13 back and forth with respect to the turntable 11. The motor 37 is a drive source that supplies a drive force for moving the grindstone 13 up and down relative to the turntable 11.

  The motor 38 is a driving source that supplies a driving force for rotating the presser roller 14. The motor 39 is a driving source that supplies a driving force for moving the presser roller 14 back and forth with respect to the grindstone 12. The motor 40 is a driving source that supplies a driving force for rotating the presser roller 15. The motor 41 is a drive source that supplies a drive force for moving the presser roller 15 back and forth with respect to the grindstone 13. The motor 42 is a driving source that supplies a driving force for moving the supply / extraction unit 16.

  The drive mechanism 18 includes a rotation mechanism 51, a rotation mechanism 52, movement mechanisms 53 and 54, a rotation mechanism 55, movement mechanisms 56 and 57, a rotation mechanism 58, a movement mechanism 59, a rotation mechanism 60, and a movement. A mechanism 61 and a moving mechanism 62 are provided.

  The rotation mechanism 51 transmits the driving force of the motor 31 to the turntable 11 to rotate the turntable 11. The rotation mechanism 52 transmits the driving force of the motor 32 to the grindstone 12 to rotate the grindstone 12. The moving mechanism 53 transmits the driving force of the motor 33 to the grindstone 12 to move the grindstone 12 forward or backward. The moving mechanism 54 transmits the driving force of the motor 34 to the grindstone 12 to move the grindstone 12 up or down.

  The rotating mechanism 55 transmits the driving force of the motor 35 to the grindstone 13 to rotate the grindstone 13. The moving mechanism 56 transmits the driving force of the motor 36 to the grindstone 13 to move the grindstone 13 forward or backward. The moving mechanism 57 transmits the driving force of the motor 37 to the grindstone 13 to move the grindstone 13 up or down.

  The rotating mechanism 58 transmits the driving force of the motor 38 to the presser roller 14 to rotate the presser roller 14. The moving mechanism 59 transmits the driving force of the motor 39 to the pressing roller 14 to move the pressing roller 14 forward or backward. The rotation mechanism 60 transmits the driving force of the motor 40 to the presser roller 15 to rotate the presser roller 15. The moving mechanism 61 transmits the driving force of the motor 41 to the press roller 15 to move the press roller 15 forward or backward.

  The movement mechanism 62 transmits the driving force of the motor 42 to the supply / extraction unit 16 to move the supply / extraction unit 16. Specifically, when the moving mechanism 62 receives a workpiece from the previous process facility, the moving mechanism 62 takes out the supply to the vicinity of the support pin 25 located at a preset workpiece supply position (see the workpiece supply position SP in FIG. 2). The unit 16 is moved. Further, after the grinding by the grinding device 1, the moving mechanism 62 starts from the vicinity of the support pin 25 located at a preset workpiece removal position (see the workpiece supply position EP in FIG. 2). The supply / withdrawing unit 16 is moved to a later process facility (hereinafter referred to as a later process facility).

When a workpiece is supplied from the previous process equipment to the supply / extraction unit 16, the detection device 19 outputs a workpiece detection signal indicating that fact.
The display device 20 includes a display screen (not shown), and displays various images on the display screen.

  The input device 21 includes a touch panel installed on the display screen of the display device 20 and a switch installed around the display screen of the display device 20. The input device 21 outputs input operation information for specifying an input operation performed by a user via a touch panel and a switch.

  The control device 22 is mainly composed of a microcomputer including a CPU 66, a ROM 67, a RAM 68, a signal input / output unit 69, and the like. The control device 22 executes various processes based on the input from the input device 21 and controls the drive unit 17 and the display device 20.

  When the detection device 19 detects that the workpiece has been supplied from the previous process equipment to the supply / extraction unit 16, the control device 22 drives the motor 42 to move the supply / extraction unit 16 to the vicinity of the workpiece supply position SP. . Further, when the supply / extraction unit 16 takes out the workpiece at the workpiece supply position EP, the control device 22 drives the motor 42 to move the supply / extraction unit 16 to the post-process equipment.

In addition, the control device 22 performs a grinding process. Here, the procedure of the grinding process will be described. This grinding process is a process repeatedly executed during the operation of the control device 22.
When this grinding process is executed, the CPU 66 of the control device 22 first determines whether or not the work is supplied to the turntable 11 by the supply / extraction unit 16 in S10 as shown in FIG. Here, when the work is not supplied (S10: NO), the process of S10 is repeated to wait until the work is supplied.

  When the workpiece is supplied (S10: YES), in S20, the support pin 25 supporting the unground workpiece is positioned between the grindstone 12 and the pressing roller 14 (hereinafter, rough cutting workpiece position). The turntable 11 is rotated so as to be disposed at the same time.

  In step S30, the presser roller 14 disposed at the roughing roller standby position set in advance so as not to come into contact with the work when the turntable 11 is rotating is set so that the presser roller 14 comes into contact with the work. Are moved forward so as to be arranged at a preset roughing roller position. When the presser roller 14 moves to the roughing roller position, the rotating presser roller 14 comes into contact with the workpiece, and the workpiece rotates about the support pin 25 as the rotation axis. The press rollers 14 and 15 start to rotate when the grinding apparatus 1 is started, and thereafter continue to rotate constantly. That is, the press rollers 14 and 15 are rotating even in a standby state in which the grinding apparatus 1 is not grinding a workpiece.

  Thereafter, in S40, the grindstone 12 arranged at the roughing grindstone standby position set in advance so as not to come into contact with the workpiece when the turntable 11 is rotating is moved forward in a preset roughing movement pattern. Let Thereby, the rotating grindstone 12 comes into contact with the workpiece, and the workpiece is ground by the grindstone 12 into the detecting element rough shape. The grindstones 12 and 13 start to rotate when the grinding apparatus 1 is started, and then continue to rotate constantly. That is, the grindstones 12 and 13 are rotating even in a standby state in which the grinding apparatus 1 is not grinding a workpiece.

As shown in FIG. 5A, the rough cutting movement pattern sequentially executes an oblique movement process, an initial cutting process, an intermediate cutting process, and a final cutting process.
In the oblique movement step, the grindstone is approached from the roughing grindstone standby position P1 set above the workpiece toward the preset initial sharpening position P2 located obliquely below the roughening grindstone standby position P1. 12 (refer to the movement direction MD11 in FIG. 5A and the movement direction MD21 in FIG. 5B). When the grindstone 12 moves to the vicinity of the initial cutting position P2, the grindstone 12 and the workpiece come into contact with each other and grinding is performed. In the oblique movement process, the grindstone 12 is moved at a preset oblique movement speed V1.

  The initial cutting process is a process of moving the grindstone 12 from the initial cutting position P2 toward the workpiece toward the preset intermediate cutting position P3 (see the moving direction MD12). The intermediate cutting position P3 has the same height as the initial cutting position P2, and is set to be closer to the workpiece than the initial cutting position P2. In the initial cutting process, the grindstone 12 is moved at a preset initial cutting speed V2.

  The intermediate cutting step is a step of moving the grindstone 12 from the intermediate cutting position P3 toward the preset final cutting position P4 so as to approach the workpiece (see the moving direction MD13). The final cutting position P4 has the same height as the intermediate cutting position P3, and is set to be closer to the workpiece than the intermediate cutting position P3. In the intermediate cutting step, the grindstone 12 is moved at a preset intermediate cutting speed V3.

  The final cutting step is a step of moving the grindstone 12 from the final cutting position P4 toward the workpiece toward the preset end position P5 (see the moving direction MD14). The end position P5 has the same height as the final cutting position P4, and is set to be closer to the workpiece than the final cutting position P4. In the final cutting process, the grindstone 12 is moved at a preset final cutting speed V4. Then, when the grindstone 12 reaches the end position P5, the process of S40 is ended.

  When the process of S40 is completed, the presser roller 14 and the grindstone 12 are moved backward in S50 as shown in FIG. As a result, the presser roller 14 moves to the roughing grindstone standby position, and the grindstone 12 moves to the roughing grindstone standby position.

  Next, in S60, the support pin 25 supporting the workpiece ground in the detection element rough shape is disposed at a position between the grindstone 13 and the presser roller 15 (hereinafter referred to as a finishing workpiece position). Then, the turntable 11 is rotated.

  In step S70, the presser roller 15 disposed at the finishing roller standby position set in advance so as not to come into contact with the work when the turntable 11 is rotating is set so that the presser roller 15 comes into contact with the work. It is moved forward so as to be arranged at a preset finishing roller position. When the presser roller 15 moves to the finishing roller position, the rotating presser roller 15 comes into contact with the workpiece, and the workpiece rotates about the support pin 25 as the rotation axis.

  Thereafter, in S80, the grindstone 13 placed at the finishing grindstone standby position set in advance so as not to contact the workpiece when the turntable 11 is rotating is moved forward in a preset finishing movement pattern. Let Thereby, the rotating grindstone 13 comes into contact with the workpiece, and the workpiece is ground into a finished shape by the grindstone 13.

As shown in FIG. 5A, this finishing movement pattern sequentially executes an oblique movement process, an initial cutting process, an intermediate cutting process, and a final cutting process.
In the oblique movement process, the grindstone is approached from the finishing grindstone standby position P11 set above the workpiece toward the workpiece toward a preset initial cutting position P12 located obliquely below the finishing grindstone standby position P11. 13 is a step of moving 13 (see movement direction MD11). When the grindstone 13 moves to the initial cutting position P12, the grindstone 13 and the workpiece come into contact with each other and grinding is started. In the oblique movement process, the grindstone 13 is moved at a preset oblique movement speed V11.

  The initial cutting step is a step of moving the grindstone 13 from the initial cutting position P12 toward the preset intermediate cutting position P13 so as to approach the workpiece (see the moving direction MD12). The intermediate cutting position P13 has the same height as the initial cutting position P12, and is set to be closer to the workpiece than the initial cutting position P12. In the initial cutting process, the grindstone 13 is moved at a preset initial cutting speed V12.

  The intermediate cutting process is a process in which the grindstone 13 is moved from the intermediate cutting position P13 toward the workpiece toward the preset final cutting position P14 (see the moving direction MD13). The final cutting position P14 has the same height as the intermediate cutting position P13, and is set to be closer to the workpiece than the intermediate cutting position P13. In the intermediate cutting step, the grindstone 13 is moved at a preset intermediate cutting speed V13.

  The final cutting step is a step of moving the grindstone 13 from the final cutting position P14 toward the preset end position P15 so as to approach the workpiece (see the moving direction MD14). The end position P15 has the same height as the final cutting position P14, and is set to be closer to the workpiece than the final cutting position P14. In the final cutting process, the grindstone 13 is moved at a preset final cutting speed V14. Then, when the grindstone 13 reaches the end position P15, the process of S80 is ended.

  When the process of S80 is completed, as shown in FIG. 4, the presser roller 15 and the grindstone 13 are moved backward in S90, and the grinding process is temporarily terminated. As a result, the presser roller 15 moves to the finishing roller standby position, and the grindstone 13 moves to the finishing grindstone standby position.

  In the manufacturing method of the detection element 102 configured as described above, the grindstones 12 and 13 are respectively the front end grinding portions 71 and 81 for grinding the part corresponding to the front end of the detection element 102 in the work, and the side surface of the detection element 102 in the work. And side grinding portions 72 and 82 for grinding portions corresponding to. And in the manufacturing method of the detection element 102, the front-end grinding surfaces 71a and 81a which contact a workpiece | work in the front-end grinding parts 71 and 81 are the edge parts 72b of the side grinding surfaces 72a and 82a which contact a workpiece | work in the side grinding parts 72 and 82. , 82b so as to protrude.

  And the manufacturing method of the detection element 102 is equipped with the diagonal movement process. In the oblique movement process, the grindstones 12 and 13 are moved from the state where the grindstones 12 and 13 are not in contact with the workpiece so that the grindstones 12 and 13 are moved closer to the workpiece along an oblique movement direction oblique to the rotation axis RA. The workpieces 12 and 13 are brought into contact with the workpiece, and the workpiece is ground with the grindstones 12 and 13 (S40, S80).

  As described above, the manufacturing method of the detection element 102 is such that the distance between the grindstones 12 and 13 and the work necessary for preventing the grindstones 12 and 13 from contacting the work is a direction perpendicular to the rotation axis RA. By moving the grindstones 12 and 13 along, the grindstones 12 and 13 can be shortened compared to the case where the workpiece is brought into contact with the workpiece. For example, as shown in FIG. 8A, when moving the grindstones 12 and 13 along the direction perpendicular to the rotation axis RA, the grindstones necessary for preventing the grindstones 12 and 13 from coming into contact with the workpiece. The distance DW1 between the workpieces 12 and 13 and the workpiece needs to be longer than the length at which the tip grinding surfaces 71a and 81a protrude from the side grinding surfaces 72a and 82a. On the other hand, as shown in FIG. 8B, when the grindstones 12 and 13 are moved along the oblique movement direction that is inclined with respect to the rotation axis RA, the grindstones 12 and 13 are prevented from coming into contact with the workpiece. The distance DW2 between the grindstones 12 and 13 required for the workpiece and the workpiece is shorter than the length at which the tip grinding surfaces 71a and 81a protrude from the side grinding surfaces 72a and 82a. For this reason, the manufacturing method of the detection element 102 can shorten the time required to move the grindstones 12 and 13, and can improve the productivity of the detection element 102.

  Further, as shown in FIG. 8A, when the grindstones 12 and 13 are moved along a direction perpendicular to the rotation axis RA, the workpieces are moved from a position where the grindstones 12 and 13 are not in contact with the workpiece. The moving distance DS1 for moving the grindstones 12, 13 to the position where grinding is completed needs to be longer than the length at which the tip grinding surfaces 71a, 81a protrude from the side grinding surfaces 72a, 82a. On the other hand, as shown in FIG. 8B, when the grindstones 12 and 13 are moved along the oblique movement direction that is oblique to the rotation axis RA, the grindstones 12 and 13 are not in contact with the workpiece. The moving distance DS2 for moving the grindstones 12, 13 to a position where the grinding of the workpiece is completed is shorter than the length at which the tip grinding surfaces 71a, 81a protrude from the side grinding surfaces 72a, 82a. For this reason, the manufacturing method of the detection element 102 can shorten the time required to move the grindstones 12 and 13, and can improve the productivity of the detection element 102.

  Moreover, in the manufacturing method of the detection element 102, the grindstones 12 and 13 are end portions 71b and 81b on the side of the front-end grinding surfaces 71a and 81a of the grindstones 12 and 13 that are not connected to the side grinding surfaces 72a and 82a. 7 (see FIG. 7A and FIG. 7B) is formed so as to protrude beyond the rotation axis RA when a portion of the workpiece corresponding to the tip of the detection element 102 is ground. As described above, when the tip grinding surfaces 71a and 81a are formed so as to protrude beyond the rotation axis RA, it is possible to avoid a situation in which a portion corresponding to the tip of the detection element 102 in the workpiece is not ground. . Further, as the length of the tip grinding surfaces 71a and 81a protruding beyond the rotation axis RA is larger, the grindstones 12 and 13 are brought into contact with the workpiece by moving the grindstone along a direction perpendicular to the rotation axis RA. In this case, the distance between the grindstones 12 and 13 and the work necessary for preventing the grindstones 12 and 13 from coming into contact with the work becomes longer. For this reason, the manufacturing method of the detection element 102 is suitable when the tip grinding surfaces 71a and 81a are formed so as to protrude beyond the rotation axis RA.

  In the embodiment described above, the unground workpiece WK1 and the rough workpiece WK2 are the workpieces in the present invention, the detection element 102 is the molded body in the present invention, and the oblique movement process in the processes of S40 and S80 is the oblique movement grinding process in the present invention. It is.

  Further, the grindstone 12 is the roughing grindstone in the present invention, the grindstone 13 is the finishing grindstone in the present invention, the oblique movement process of S40 is the rough grinding process in the present invention, and the oblique movement process in S80 is the finish grinding in the present invention. It is a process.

(Second Embodiment)
A second embodiment of the present invention will be described below with reference to the drawings.
The spark plug 201 of the embodiment to which the present invention is applied includes an insulator 202, a metal shell 203, a center electrode 204, a ground electrode 205, and a terminal metal fitting 206, as shown in FIG. In FIG. 9, the front end side of the spark plug 201 is shown as the lower side, and the rear end side is shown as the upper side.

  The insulator 202 is a member formed by firing alumina or the like, and is formed in a cylindrical shape extending in the axial direction DA. The insulator 202 is formed with a shaft hole 221 that penetrates along the axial direction DA. On the inner peripheral wall of the shaft hole 221, a step portion 221a that protrudes radially inward is formed.

  The insulator 202 includes a flange portion 222, a rear end side body portion 223, a front end side body portion 224, and a leg length portion 225. The flange portion 222 is a portion formed in an annular shape extending outward from the outer periphery of the insulator 202 along the radial direction. The rear end side body portion 223 is a portion formed in a cylindrical shape extending in the axial direction DA on the rear end side from the flange portion 222. The front end side body portion 224 is a portion formed in a cylindrical shape extending in the axial direction DA on the front end side with respect to the flange portion 222. The front end side body part 224 is formed so that the outer diameter thereof is smaller than the outer diameter of the rear end side body part 223. The long leg portion 225 is a portion formed in a cylindrical shape extending in the axial direction DA on the distal end side with respect to the distal end side body portion 224. The long leg portion 225 is formed such that its outer diameter is smaller than the outer diameter of the distal end side body portion 224. Further, the long leg portion 225 is formed so that the outer diameter decreases from the rear end side toward the front end side.

  The metal shell 203 is a member for fixing the spark plug 201 to the engine head, and is formed in a cylindrical shape from a metal such as low carbon steel. The metal shell 203 includes a through hole 203a penetrating along the axial direction DA. The metal shell 203 includes a screw portion 231, a seat portion 232, a screw neck 233, a tool engaging portion 234, and a caulking portion 235.

  The screw portion 231 is a cylindrical portion extending in the axial direction DA, and a male screw is formed on the outer periphery thereof. On the inner peripheral wall of the screw portion 231, a step portion 231 a that protrudes radially inward is formed. The seat portion 232 is a portion formed in a cylindrical shape extending in the axial direction DA on the rear end side of the screw portion 231. The seat portion 232 is formed so that its outer diameter is larger than the outer diameter of the screw portion 231.

  The screw neck 233 is a part disposed between the screw part 231 and the seat part 232. The screw neck 233 is formed so that the outer diameter thereof is substantially the same as the outer diameter of the screw portion 231. A gasket 211 formed in an annular shape is fitted into the screw neck 233. When the spark plug 201 is attached to the engine head mounting portion, the gasket 211 is crushed and deformed between the seat portion 232 and the engine head mounting portion. As a result, the gasket 211 is in close contact with the seat portion 232 and the mounting portion of the engine head, and airtightness between the spark plug 201 and the engine head is ensured.

  The tool engaging portion 234 extends outward in the radial direction on the rear end side from the seat portion 232, and has an outer periphery formed in a hexagonal plate shape. The tool engagement portion 234 is a part for fitting an attachment tool such as a wrench when attaching the spark plug 201 to the engine head.

  The caulking portion 235 is a member that protrudes from the rear end side of the tool engaging portion 234 toward the rear end side, and is bent inward to hold the insulator 202 in the metal shell 203.

  The insulator 202 is inserted into the through hole 203 a of the metal shell 203. The insulator 202 has a stepped portion 202a formed between the front end side body portion 224 and the leg long portion 225 supported by the stepped portion 231a of the screw portion 231 through the packing 212, so that Be contained. Further, packings 213 and 214 formed in an annular shape are inserted between the inner peripheral surface of the metal shell 203 and the outer peripheral surface of the insulator 202 on the upper side of the flange 222 of the insulator 202, and the packing 213 and The talc powder 215 is filled between the packing 214. In this state, when the caulking portion 235 is caulked, the insulator 202 is pressed toward the distal end side through the packing 214, the talc powder 215, and the packing 213. Thereby, the insulator 202 is firmly fixed to the metal shell 203.

  The center electrode 204 includes an electrode base material 241 and a core material 242. The electrode base material 241 is a member formed in a rod shape from nickel or an alloy containing nickel as a main component. The core material 242 is a member formed of copper or an alloy containing copper as a main component, and is embedded in the electrode base material 241. The center electrode 204 is formed in a columnar shape as a whole, and is formed so that the end surface on the tip side is flat. An electrode tip 243 is joined to the tip of the center electrode 204. The electrode tip 243 is a member made of an alloy mainly composed of a noble metal (for example, iridium) and formed in a columnar shape.

  The center electrode 204 is inserted into the shaft hole 221 in the leg long portion 225 of the insulator 202, and is fixed to the insulator 202 so that the tip of the center electrode 204 protrudes from the tip of the insulator 202. The center electrode 204 is electrically connected to the terminal fitting 206 via the sealing materials 217 and 218 inserted in the shaft hole 221 and the resistor 219. The sealing materials 217 and 218 are, for example, a mixture of silver, copper, or a metal such as an alloy containing copper as a main component and glass. The resistor 219 is formed in a cylindrical shape by mixing, for example, carbon, ceramic, and glass. The sealing material 217 is filled in the shaft hole 221 on the rear end side of the center electrode 204. The resistor 219 is disposed in the shaft hole 221 on the rear end side with respect to the sealing material 217. The sealing material 218 is filled in the shaft hole 221 on the rear end side of the resistor 219.

  The ground electrode 205 is a member formed in an L shape from a metal having high corrosion resistance (for example, a nickel alloy). The ground electrode 205 is installed such that one end thereof is connected to the tip of the threaded portion 231 of the metal shell 203 by welding and the other end faces the tip of the center electrode 204 on the axis AL. A noble metal tip 251 is joined to the other end of the ground electrode 205. The noble metal tip 251 is a member made of a noble metal (for example, platinum alloy) in a cylindrical shape, and is installed so as to face the electrode tip 243 on the axis AL.

  The terminal fitting 206 is a member formed of a metal such as low carbon steel. The terminal fitting 206 is inserted into the shaft hole 221 in the rear end body portion 223 of the insulator 202 and fixed to the insulator 202 so that the end on the rear end side protrudes from the rear end of the insulator 202. Is done. The end of the terminal fitting 206 on the front end side is in contact with the sealing material 218, whereby the terminal fitting 206 is electrically connected to the center electrode 204.

Next, a method for forming the insulator 202 will be described.
The grinding apparatus 1 according to the second embodiment is different from the first embodiment in that the shapes of the grindstones 12 and 13 are changed.

  The grindstone 12 of the second embodiment is for grinding a workpiece formed in a cylindrical shape by firing alumina or the like into a predetermined insulator roughing shape (see the roughing workpiece WK11 in FIG. 10). is there. The grindstone 12 is a columnar member whose circumferential surface is formed into a shape corresponding to the shape of roughened insulator.

  The grindstone 13 of the second embodiment grinds a workpiece ground to an insulator roughing shape (see the roughing workpiece WK11 in FIG. 10) to a preset insulator finishing shape (see the finished workpiece WK12 in FIG. 10). Is to do. The grindstone 13 is a cylindrical member whose circumferential surface is formed into a shape corresponding to the insulator finish shape.

  The manufacturing method of the insulator 202 configured as described above is the same manufacturing method as that of the first embodiment, and the productivity when the insulator 202 is manufactured using the grindstones 12 and 13 can be improved.

In the embodiment described above, the insulator 202 is a molded body in the present invention.
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, As long as it belongs to the technical scope of this invention, a various form can be taken.

  For example, in the above embodiment, the tip grinding surfaces 71a and 81a are formed so as to protrude beyond the rotation axis RA. However, the end portions 71b and 81b of the tip grinding surfaces 71a and 81a may be formed so as to coincide with the rotation axis RA when grinding a portion corresponding to the tip of the detection element 102 in the workpiece. Good.

DESCRIPTION OF SYMBOLS 1 ... Grinding device, 11 ... Turntable, 12 ... Grinding wheel, 13 ... Grinding wheel, 14 ... Roller, 15 ... Roller, 16 ... Drive part, 17 ... Drive mechanism, 18 ... Display device, 19 ... Input device, 20 ... Control device 71, 81 ... tip grinding part, 71a, 81a ... tip grinding surface, 71b, 81b ... end part, 72, 82 ... side grinding part, 72a, 82a ... side grinding surface, 72b, 82b ... end part, 101 ... oxygen Sensor 102 Detecting element 201 Spark plug 202 Insulator WK1 Unground workpiece WK11 Roughing workpiece WK12 Finishing workpiece WK2 Roughing workpiece WK3 Finishing workpiece

Claims (5)

A method of manufacturing a molded body formed by grinding with a grindstone while rotating a workpiece to be processed around a preset rotation axis,
The grindstone includes a tip grinding portion for grinding a portion corresponding to the tip of the molded body in the workpiece, and a side grinding portion for grinding a portion corresponding to the side surface of the molded body in the workpiece. A tip grinding surface that is a surface in contact with the workpiece in the tip grinding portion is formed so as to protrude from an end of a side grinding surface that is a surface in contact with the workpiece in the side grinding portion,
The grindstone is moved from the state where the grindstone is not in contact with the workpiece to move toward the workpiece along an oblique movement direction that is inclined with respect to the rotation axis. The manufacturing method of the molded object characterized by including the oblique movement grinding process which contacts the process member and grinds the to-be-processed member with the said grindstone. In the grindstone, the end of the grindstone that is not connected to the end of the side grinding surface of the grinded surface of the grindstone is grinding a portion corresponding to the tip of the molded body in the workpiece. 2. The method for producing a molded body according to claim 1, wherein the molded body is sometimes formed so as to coincide with the rotating shaft or protrude beyond the rotating shaft. The grindstone includes a roughing grindstone that grinds the workpiece to a preset roughing shape, and a finishing grindstone that grinds the workpiece to a preset finish shape,
The oblique movement grinding step includes at least a rough grinding step of grinding the workpiece by moving the roughing grindstone in the oblique movement direction, and moving the finishing grindstone in the oblique movement direction. The method for producing a molded body according to claim 1, comprising any one of a finish grinding step of grinding a workpiece.   The manufacturing method of the oxygen sensor characterized by manufacturing the molded object used as the detection element of an oxygen sensor with the manufacturing method of any one of Claims 1-3.   The manufacturing method of the spark plug characterized by manufacturing the molded object used as the insulator of a spark plug with the manufacturing method of any one of Claims 1-3.

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